Space

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Lawmakers writing NASA’s budget want a cheaper upper stage for the SLS rocket


Eliminating the Block 1B upgrade now would save NASA at least $500 million per year.

Artist’s illustration of the Boeing-developed Exploration Upper Stage, with four hydrogen-fueled RL10 engines. Credit: NASA

Not surprisingly, Congress is pushing back against the Trump administration’s proposal to cancel the Space Launch System, the behemoth rocket NASA has developed to propel astronauts back to the Moon.

Spending bills making their way through both houses of Congress reject the White House’s plan to wind down the SLS rocket after two more launches, but the text of a draft budget recently released by the House Appropriations Committee suggests an openness to making some major changes to the program.

The next SLS flight, called Artemis II, is scheduled to lift off early next year to send a crew of four astronauts around the far side of the Moon. Artemis III will follow a few years later on a mission to attempt a crew lunar landing at the Moon’s south pole. These missions follow Artemis I, a successful unpiloted test flight in 2022.

After Artemis III, the official policy of the Trump administration is to terminate the SLS program, along with the Orion crew capsule designed to launch on top of the rocket. The White House also proposed canceling NASA’s Gateway, a mini-space station to be placed in orbit around the Moon. NASA would instead procure commercial launches and commercial spacecraft to ferry astronauts between the Earth and the Moon, while focusing the agency’s long-term gaze toward Mars.

CYA EUS?

House and Senate appropriations bills would preserve SLS, Orion, and the Gateway. However, the House version of NASA’s budget has an interesting paragraph directing NASA to explore cheaper, faster options for a new SLS upper stage.

NASA has tasked Boeing, which also builds SLS core stages, to develop an Exploration Upper Stage for debut on the Artemis IV mission, the fourth flight of the Space Launch System. This new upper stage would have large propellant tanks and carry four engines instead of the single engine used on the rocket’s interim upper stage, which NASA is using for the first three SLS flights.

The House version of NASA’s fiscal year 2026 budget raises questions about the long-term future of the Exploration Upper Stage. In one section of the bill, House lawmakers would direct NASA to “evaluate alternatives to the current Exploration Upper Stage (EUS) design for SLS.” The committee members wrote the evaluation should focus on reducing development and production costs, shortening the schedule, and maintaining the SLS rocket’s lift capability.

“NASA should also evaluate how alternative designs could support the long-term evolution of SLS and broader exploration goals beyond low-Earth orbit,” the lawmakers wrote. “NASA is directed to assess various propulsion systems, stage configurations, infrastructure compatibility, commercial and international collaboration opportunities, and the cost and schedule impacts of each alternative.”

The SLS rocket is expensive, projected to cost at least $2.5 billion per launch, not counting development costs or expenses related to the Orion spacecraft and the ground systems required to launch it at Kennedy Space Center in Florida. Those figures bring the total cost of an Artemis mission using SLS and Orion to more than $4 billion, according to NASA’s inspector general.

NASA’s Block 1B version of the SLS rocket will be substantially larger than Block 1. Credit: NASA

The EUS is likewise an expensive undertaking. Last year, NASA’s inspector general reported that the new upper stage’s development costs had ballooned from $962 million to $2.8 billion, and the Boeing-led project had been delayed more than six years. The version of the SLS rocket with the EUS, known as Block 1B, is supposed to deliver a 40 percent increase in performance over the Block 1 configuration used on the first three Space Launch System flights. Overall, NASA’s inspector general projected Block 1B’s development costs to total $5.7 billion.

Eliminating the Block 1B upgrade now would save NASA at least $500 million per year, and perhaps more if NASA could also end work on a costly mobile launch tower specifically designed to support SLS Block 1B missions.

NASA can’t go back to the interim upper stage, which is based on the design of the upper stage that flew on United Launch Alliance’s (ULA’s) now-retired Delta IV Heavy rocket. ULA has shut down its Delta production line, so there’s no way to build any more. What ULA does have is a new high-energy upper stage called Centaur V. This upper stage is sized for ULA’s new Vulcan rocket, with more capability than the interim upper stage but with lower performance than the larger EUS.

A season of compromise, maybe

Ars’ Eric Berger wrote last year about the possibility of flying the Centaur V upper stage on SLS missions.

Incorporating the Centaur V wouldn’t maintain the SLS rocket’s lift capability, as the House committee calls for in its appropriations bill. The primary reason for improving the rocket’s performance is to give SLS Block 1B enough oomph to carry “co-manifested” payloads, meaning it can launch an Orion crew capsule and equipment for NASA’s Gateway lunar space station on a single flight. The lunar Gateway is also teed up for cancellation in Trump’s budget proposal, but both congressional appropriations bills would save it, too. If the Gateway escapes cancellation, there are ways to launch its modules on commercial rockets.

Blue Origin also has an upper stage that could conceivably fly on the Space Launch System. But the second stage for Blue Origin’s New Glenn rocket would be a more challenging match for SLS for several reasons, chiefly its 7-meter (23-foot) diameter—too wide to be a drop-in replacement for the interim upper stage used on Block 1. ULA’s Centaur V is much closer in size to the existing upper stage.

The House budget bill has passed a key subcommittee vote but won’t receive a vote from the full appropriations committee until after Congress’s August recess. A markup of the bill by the House Appropriations Committee scheduled for Thursday was postponed after Speaker Mike Johnson announced an early start to the recess this week.

Ars reported last week on the broad strokes of how the House and Senate appropriations bills would affect NASA. Since then, members of the House Appropriations Committee released the text of the report attached to their version of the NASA budget. The report, which includes the paragraph on the Exploration Upper Stage, provides policy guidance and more detailed direction on where NASA should spend its money.

The House’s draft budget includes $2.5 billion for the Space Launch System, close to this year’s funding level and $500 million more than the Trump administration’s request for the next fiscal year, which begins October 1. The budget would continue development of SLS Block 1B and the Exploration Upper Stage while NASA completes a six-month study of alternatives.

The report attached to the Senate appropriations bill for NASA has no specific instructions regarding the Exploration Upper Stage. But like the House bill, the Senate’s draft budget directs NASA to continue ordering spares and long-lead parts for SLS and Orion missions beyond Artemis III. Both versions of the NASA budget require the agency to continue with SLS and Orion until a suitable commercial, human-rated rocket and crew vehicle are proven ready for service.

In a further indication of Congress’ position on the SLS and Orion programs, lawmakers set aside more than $4 billion for the procurement of SLS rockets for the Artemis IV and Artemis V rockets in the reconciliation bill signed into law by President Donald Trump earlier this month.

Congress must pass a series of federal appropriations bills by October 1, when funding for the current fiscal year runs out. If Congress doesn’t act by then, it could pass a continuing resolution to maintain funding at levels close to this year’s budget or face a government shutdown.

Lawmakers will reconvene in Washington, DC, in early September in hopes of finishing work on the fiscal year 2026 budget. The section of the budget that includes NASA still must go through a markup hearing by the House Appropriations Committee and pass floor votes in the House and Senate. Then the two chambers will have to come to a compromise on the differences in their appropriations bill. Only then can the budget be put to another vote in each chamber and go to the White House for Trump’s signature.

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Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

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SpaceX launches a pair of NASA satellites to probe the origins of space weather


“This is going to really help us understand how to predict space weather in the magnetosphere.”

This artist’s illustration of the Earth’s magnetosphere shows the solar wind (left) streaming from the Sun, and then most of it being blocked by Earth’s magnetic field. The magnetic field lines seen here fold in toward Earth’s surface at the poles, creating polar cusps. Credit: NASA/Goddard Space Flight Center

Two NASA satellites rocketed into orbit from California aboard a SpaceX Falcon 9 rocket Wednesday, commencing a $170 million mission to study a phenomenon of space physics that has eluded researchers since the dawn of the Space Age.

The twin spacecraft are part of the NASA-funded TRACERS mission, which will spend at least a year measuring plasma conditions in narrow regions of Earth’s magnetic field known as polar cusps. As the name suggests, these regions are located over the poles. They play an important but poorly understood role in creating colorful auroras as plasma streaming out from the Sun interacts with the magnetic field surrounding Earth.

The same process drives geomagnetic storms capable of disrupting GPS navigation, radio communications, electrical grids, and satellite operations. These outbursts are usually triggered by solar flares or coronal mass ejections that send blobs of plasma out into the Solar System. If one of these flows happens to be aimed at Earth, we are treated with auroras but vulnerable to the storm’s harmful effects.

For example, an extreme geomagnetic storm last year degraded GPS navigation signals, resulting in more than $500 million in economic losses in the agriculture sector as farms temporarily suspended spring planting. In 2022, a period of elevated solar activity contributed to the loss of 40 SpaceX Starlink satellites.

“Understanding our Sun and the space weather it produces is more important to us here on Earth, I think, than most realize,” said Joe Westlake, director of NASA’s heliophysics division.

NASA’s two TRACERS satellites launched Wednesday aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base, California. Credit: SpaceX

The launch of TRACERS was delayed 24 hours after a regional power outage disrupted air traffic control over the Pacific Ocean near the Falcon 9 launch site on California’s Central Coast, according to the Federal Aviation Administration. SpaceX called off the countdown Tuesday less than a minute before liftoff, then rescheduled the flight for Wednesday.

TRACERS, short for Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites, will study a process known as magnetic reconnection. As particles in the solar wind head out into the Solar System at up to 1 million mph, they bring along pieces of the Sun’s magnetic field. When the solar wind reaches our neighborhood, it begins interacting with Earth’s magnetic field.

The high-energy collision breaks and reconnects magnetic field lines, flinging solar wind particles across Earth’s magnetosphere at speeds that can approach the speed of light. Earth’s field draws some of these particles into the polar cusps, down toward the upper atmosphere. This is what creates dazzling auroral light shows and potentially damaging geomagnetic storms.

Over our heads

But scientists still aren’t sure how it all works, despite the fact that it’s happening right over our heads, within the reach of countless satellites in low-Earth orbit. But a single spacecraft won’t do the job. Scientists need at least two spacecraft, each positioned in bespoke polar orbits and specially instrumented to measure magnetic fields, electric fields, electrons, and ions.

That’s because magnetic reconnection is a dynamic process, and a single satellite would provide just a snapshot of conditions over the polar cusps every 90 minutes. By the time the satellite comes back around on another orbit, conditions will have changed, but scientists wouldn’t know how or why, according to David Miles, principal investigator for the TRACERS mission at the University of Iowa.

“You can’t tell, is that because the system itself is changing?” Miles said. “Is that because this magnetic reconnection, the coupling process, is moving around? Is it turning on and off, and if it’s turning on and off, how quickly can it do it? Those are fundamental things that we need to understand… how the solar wind arriving at the Earth does or doesn’t transfer energy to the Earth system, which has this downstream effect of space weather.”

This is why the tandem part of the TRACERS name is important. The novel part of this mission is it features two identical spacecraft, each about the size of a washing machine flying at an altitude of 367 miles (590 kilometers). Over the course of the next few weeks, the TRACERS satellites will drift into a formation with one trailing the other by about two minutes as they zip around the world at nearly five miles per second. This positioning will allow the satellites to sample the polar cusps one right after the other, instead of forcing scientists to wait another 90 minutes for a data refresh.

With TRACERS, scientists hope to pick apart smaller, fast-moving changes with each satellite pass. Within a year, TRACERS should collect 3,000 measurements of magnetic reconnections, a sample size large enough to start identifying why some space weather events evolve differently than others.

“Not only will it get a global picture of reconnection in the magnetosphere, but it’s also going to be able to statistically study how reconnection depends on the state of the solar wind,” said John Dorelli, TRACERS mission scientist at NASA’s Goddard Space Flight Center. “This is going to really help us understand how to predict space weather in the magnetosphere.”

One of the two TRACERS satellites undergoes launch preparations at Millennium Space Systems, the spacecraft’s manufacturer. Credit: Millennium Space Systems

“If we can understand these various different situations, whether it happens suddenly if you have one particular kind of event, or it happens in lots of different places, then we have a better way to model that and say, ‘Ah, here’s the likelihood of seeing a certain kind of effect that would affect humans,'” said Craig Kletzing, the principal investigator who led the TRACERS science team until his death in 2023.

There is broader knowledge to be gained with a mission like TRACERS. Magnetic reconnection is ubiquitous throughout the Universe, and the same physical processes produce solar flares and coronal mass ejections from the Sun.

Hitchhiking to orbit

Several other satellites shared the ride to space with TRACERS on Wednesday.

These secondary payloads included a NASA-sponsored mission named PExT, a small technology demonstration satellite carrying an experimental communications package capable of connecting with three different networks: NASA’s government-owned Tracking and Data Relay Satellites (TDRS) and commercial satellite networks owned by SES and Viasat.

What’s unique about the Polylingual Experimental Terminal, or PExT, is its ability to roam across multiple satellite relay networks. The International Space Station and other satellites in low-Earth orbit currently connect to controllers on the ground through NASA’s TDRS satellites. But NASA will retire its TDRS satellites in the 2030s and begin purchasing data relay services using commercial satellite networks.

The space agency expects to have multiple data relay providers, so radios on future NASA satellites must be flexible enough to switch between networks mid-mission. PExT is a pathfinder for these future missions.

Another NASA-funded tech demo named Athena EPIC was also aboard the Falcon 9 rocket. Led by NASA’s Langley Research Center, this mission uses a scalable satellite platform developed by a company named NovaWurks, using building blocks to piece together everything a spacecraft needs to operate in space.

Athena EPIC hosts a single science instrument to measure how much energy Earth radiates into space, an important data point for climate research. But the mission’s real goal is to showcase how an adaptable satellite design, such as this one using NovaWurks’ building block approach, might be useful for future NASA missions.

A handful of other payloads rounded out the payload list for Wednesday’s launch. They included REAL, a NASA-funded CubeSat project to investigate the Van Allen radiation belts and space weather, and LIDE, an experimental 5G communications satellite backed by the European Space Agency. Five commercial spacecraft from the Australian company Skykraft also launched to join a constellation of small satellites to provide tracking and voice communications between air traffic controllers and aircraft over remote parts of the world.

Photo of Stephen Clark

Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

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What exactly is Golden Dome? This Space Force general owes Trump an answer.


“Basically, I’ve been given 60 days to come up with the objective architecture.”

Gen. Michael Guetlein, overseeing the development of the Golden Dome missile defense system, looks on as President Donald Trump speaks in the Oval Office of the White House on May 20, 2025, in Washington, DC. Credit: Jim Watson/AFP via Getty Images

The newly installed head of the Pentagon’s Golden Dome missile defense shield, a monumental undertaking projected to cost $175 billion over the next three years, knows the clock is ticking to show President Donald Trump some results before the end of his term in the White House.

“We are going to try to craft a schedule to have incremental demonstrations every six months because we are on a short timeline,” said Gen. Michael Guetlein, who was confirmed by the Senate last week to become the military’s Golden Dome czar.

Speaking on Tuesday, his second day on the job leading the Golden Dome initiative, Guetlein said his team will “move out with a sense of urgency and move out with incremental wins” as the military races to meet Trump’s timeline.

Guetlein discussed his new job with retired Gen. John “Jay” Raymond, the first chief of the Space Force, at an event in Washington, DC, hosted by the Space Foundation.

Analysts and retired military officials doubt the Pentagon can achieve all of Trump’s Golden Dome promises by the end of 2028. It’s not yet clear what the Pentagon can finish in three years, but Guetlein said Thursday his team will deliver “a capability” on that schedule. “We’ve got to exploit anything and everything we’ve possibly got,” he said, echoing a tenet of Space Force policy to “exploit what we have, buy what we can, and build what we must.”

This means the Space Force will lean heavily on commercial companies, research labs, academia, and, in the case of Canada, international partners to build the Golden Dome.

“Golden Dome for America requires a whole-of-nation response to deter and, if necessary, to defeat attacks against the United States,” the Defense Department said in a statement Tuesday. “We have the technological foundation, national talent, and decisive leadership to advance our nation’s defenses. We are proud to stand behind Gen. Mike Guetlein as he takes the helm of this national imperative.”

President Trump signed an executive order in January calling for the development of a layered missile defense shield to protect the US homeland. He initially called the project the Iron Dome for America, named for Israel’s Iron Dome missile defense system. But Israel’s Iron Dome, which has proven effective against missile attacks from Iran and its proxies in the Middle East, only has to defend an area the size of New Jersey. The Pentagon’s system, now named Golden Dome, will ostensibly cover the entire United States.

Lay of the land

Advocates for the Golden Dome point to recent events to justify the program. These include Russia’s first use of an intermediate-range ballistic missile against Ukraine last year, and Ukraine’s successful drone attack on a Russian airbase last month. Waves of Iranian missile and drone attacks on Israel have tested the mettle of that country’s Iron Dome.

In the January 27 executive order, the White House said the military’s plan must defend against many types of aerial threats, including ballistic, hypersonic, and advanced cruise missiles, plus “other next-generation aerial attacks,” a category that appears to include drones and shorter-range unguided missiles.

This will require a network of sensors on the ground and in space, including heat-seeking sensors and radars to track incoming aerial threats, and interceptors based on the ground, at sea, and in space capable of destroying missiles at any point in flight—boost phase, midcourse, and during final approach to a target.

This illustration shows how the Missile Defense Agency’s HBTSS satellites can track hypersonic missiles as they glide and maneuver through the atmosphere, evading detection by conventional missile-tracking spacecraft, such as the Space Force’s DSP and SBIRS satellites. Credit: Northrop Grumman

The good news for backers of the Golden Dome program is that the Pentagon and commercial industry were developing most of these elements before Trump’s executive order. The Space Development Agency (SDA) launched a batch of prototype missile-tracking and data-relay satellites in 2023, pathfinders for a constellation of hundreds of spacecraft in low-Earth orbit that will begin launching later this year.

In some cases, the military has already fielded Golden Dome components in combat. The Army has operated the Patriot missile system since the 1980s and the Terminal High Altitude Area Defense (THAAD) interceptors for more than 15 years to defend against lower-level threats like small rockets, aircraft, and drones. The Navy’s Aegis Ballistic Missile Defense System uses sea-launched interceptors to target longer-range missiles in space.

The Missile Defense Agency manages the Ground-based Midcourse Defense (GMD) program, which consists of operational silo-launched missile interceptors based in Alaska and California that could be used to defend against a limited missile strike from a rogue state like North Korea.

GMD has cost approximately $70 billion to date and has worked a little more than half the time the military has tested it against a missile target. On the plus side, GMD has achieved four straight successful intercepts in tests since 2014. But despite its immense cost, GMD is antiquated and would not be effective against a large volley of missiles coming from another nuclear superpower, like China.

Golden Dome will bring all of these systems together, and add more to the mix in order to “double down on the protection of the homeland and protect our American citizens,” Guetlein said.

What’s next?

Guetlein identified several short-term priorities for what is officially called the “Office of Golden Dome for America.” One of them is to begin bringing together the military’s existing missile detection and tracking assets, ground- and sea-based interceptors, and the communication pathways, or “comm pipes,” to connect all the pieces in a sophisticated command-and-control network.

“That includes the sensors, that includes the shooters, as well as the comm pipes,” Guetlein said. “How do we bring all that to bear simultaneously in protection of the homeland, while utilizing the capabilities that are already there and not trying to re-create them?”

The Pentagon said in a statement Tuesday that Guetlein’s office will devise an “objective architecture” for the missile defense shield and “socialize” it by late September. This presumably means sharing some information about the architecture with Congress and the public. So far, Space Force officials have hesitated to provide any specifics, at least in public statements and congressional hearings. They often prefer to describe Golden Dome as a “system of systems” instead of something entirely new.

“Basically, I’ve been given 60 days to come up with the objective architecture. I owe that back to the Deputy Secretary of Defense in 60 days,” Guetlein said. “So, in 60 days, I’ll be able to talk in depth about, ‘Hey, this is our vision for what we want to get after for Golden Dome.'”

Although the major pieces of a layered anti-missile system like Golden Dome may appear obvious to anyone with a casual familiarity with missile defense and space—we just named a few of these elements above—the Trump administration has not published any document describing what the Pentagon might actually achieve in the next three years.

Despite the lack of detail, Congress voted to approve $25 billion as a down payment for Golden Dome in the Trump-backed “One Big Beautiful Bill” signed into law July 4. The bulk of the Golden Dome-related budget is earmarked for procurement of more Patriot and THAAD missile batteries, an increase in funding for SDA’s missile-tracking satellites, ballistic missile defense command-and-control networks, and development of “long-range kill chains” for combat targeting.

Two of the US Army’s THAAD missile batteries are seen deployed in Israel in this 2019 photo. Credit: US Army/Staff Sgt. Cory Payne

So, most of the funding allocated to Golden Dome over the next year will go toward bolstering programs already in the Pentagon’s portfolio. But the military will tie them all together with an integrated command-and-control system that can sense an adversarial missile launch, plot its trajectory, and then generate a targeting solution and send it to an interceptor on the ground or in space to eliminate the threat.

Eventually, military leaders want satellites to handle all of these tasks autonomously in space and do it fast enough for US or allied forces to respond to an imminent threat.

“We know how to get data,” a retired senior military official recently told Ars. “The question is, how do you fuse that data in real time with the characteristics of a fire control system, which means real-time feedback of all this data, filtering that data, filtering out sensors that aren’t helping as much as other ones, and then using that to actually command and control against a large-scale attack of diverse threats.

“I feel like those are still two different things,” said the official, who spoke on background with Ars. “It’s one thing to have all the data and be able to process it. It’s another thing to be able to put it into an active, real-time fire control system.”

Trump introduced Guetlein, the Space Force’s former vice chief of space operations, as his nominee for director of the Golden Dome program in an Oval Office event on May 20. At the time, Trump announced the government had “officially selected an architecture” for Golden Dome. That appears to still be the work in front of Guetlein and his team, which is set to grow with new hiring but will remain “small and flat,” the general said Tuesday.

Guetlein has a compelling résumé to lead Golden Dome. Before becoming the second-ranking officer in the Space Force, he served as head of Space Systems Command, which is responsible for most of the service’s acquisition and procurement activities. His prior assignments included stints as deputy director of the National Reconnaissance Office, program executive at the Missile Defense Agency, program manager for the military’s missile warning satellites, and corporate fellow at SpaceX.

Weapons in space

Guetlein identified command and control and the development of space-based interceptors as two of the most pressing technical challenges for Golden Dome. He believes the command-and-control problem can be “overcome in pretty short order.”

“I think the real technical challenge will be building the space-based interceptor,” Guetlein said. “That technology exists. I believe we have proven every element of the physics that we can make it work. What we have not proven is, first, can I do it economically, and then second, can I do it at scale? Can I build enough satellites to get after the threat? Can I expand the industrial base fast enough to build those satellites? Do I have enough raw materials, etc.?”

This is the challenge that ultimately killed the Strategic Defense Initiative (SDI) or “Star Wars” program proposed by former President Ronald Reagan in the 1980s as a way to counter the threat of a nuclear missile attack from the Soviet Union. The first concept for SDI called for 10,000 interceptors to be launched into Earth orbit. This was pared down to 4,600, then finally to fewer than 1,000 before the cancellation of the space-based element in 1993.

Thirty years ago, the United States lacked the technology and industrial capacity to build and launch so many satellites. It’s a different story today. SpaceX has launched more than 9,000 Starlink communications satellites in six years, and Amazon recently kicked off the deployment of more than 3,200 Internet satellites of its own.

Space-based interceptors are a key tenet of Trump’s executive order on Golden Dome. Specifically, the order calls for space-based interceptors capable of striking a ballistic missile during its boost phase shortly after launch. These interceptors would essentially be small satellites positioned in low-Earth orbit, likely a few hundred miles above the planet, circling the world every 90 minutes ready for commands to prevent nuclear Armageddon.

A Standard Missile 3 Block IIA launches from the Aegis Ashore Missile Defense Test Complex at the Pacific Missile Range Facility in Kauai, Hawaii, on December 10, 2018, during a test to intercept an intermediate-range ballistic missile target in space. Credit: Mark Wright/DOD

Reuters reported Tuesday that the Defense Department, which reportedly favored SpaceX to play a central role in Golden Dome, is now looking to other companies, including Amazon Kuiper and other big defense contractors. SpaceX founder Elon Musk has fallen out of favor with the Trump administration, but the company’s production line continues to churn out spacecraft for the National Reconnaissance Office’s global constellation of spy satellites. And it’s clear the cheapest and most reliable way to launch Golden Dome interceptors into orbit will be using SpaceX’s Falcon 9 rocket.

How many space-based interceptors?

“I would envision that there would be certainly more than 1,000 of those in orbit in different orbital planes,” said retired Air Force Gen. Henry “Trey” Obering III, a senior executive advisor at Booz Allen Hamilton and former commander of the Missile Defense Agency. “You could optimize those orbital planes against the Russian threat or Chinese threat, or both, or all the above, between Iran, North Korea, China, and Russia.”

In an interview with Ars, Obering suggested the interceptors could be modest in size and mass, somewhat smaller than SpaceX’s Starlink satellites, and could launch 100 or 200 at a time on a rocket like SpaceX’s Falcon 9. None of this capability existed in the Reagan era.

Taking all of that into account, it’s understandable why Guetlein and others believe Golden Dome is doable.

But major questions remain unanswered about its ultimate cost and the realism of Trump’s three-year schedule. Some former defense officials have questioned the technical viability of using space-based interceptors to target a missile during its boost phase, within the first few minutes of launch.

It’s true that there are also real emerging threats, such as hypersonic missiles and drones, that the US military is currently ill-equipped to defend against.

“The strategic threats are diversifying, and then the actors are diversifying,” the former military space official told Ars. “It’s no longer just Russia. It’s China now, and to a lesser extent, North Korea and potentially Iran. We’ll see where that goes. So, when you put that all together, our ability to deter and convince a potential adversary, or at least make them really uncertain about how successful they could be with a strike, is degraded compared to what it used to be.”

The official said the Trump administration teed up the Golden Dome executive order without adequately explaining the reasons for it. That’s a political failing that could come back to bite the program. The lack of clarity didn’t stop Congress from approving this year’s $25 billion down payment, but there are more key decision points ahead.

“I’m a little disappointed no one’s really defined the problem very well,” the retired military official said. “It definitely started out as a solution without a problem statement, like, ‘I need an Iron Dome, just like Israel.’ But I feel like the entire effort would benefit from a better problem statement.”

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Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

What exactly is Golden Dome? This Space Force general owes Trump an answer. Read More »

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Trump wants to “eliminate or expedite” environmental rules for rocket launches


Who cares about environmental impacts?

SpaceX, other commercial launch firms, have been seeking this change in policy.

In the background, a Falcon 9 rocket climbs away from Space Launch Complex 40 at Cape Canaveral Space Force Station, Florida. Another Falcon 9 stands on its launch pad at neighboring Kennedy Space Center awaiting its opportunity to fly.

The Trump administration is considering slashing rules meant to protect the environment and the public during commercial rocket launches, changes that companies like Elon Musk’s SpaceX have long sought.

A draft executive order being circulated among federal agencies, and viewed by ProPublica, directs Secretary of Transportation Sean Duffy to “use all available authorities to eliminate or expedite” environmental reviews for launch licenses. It could also, in time, require states to allow more launches or even more launch sites—known as spaceports—along their coastlines.

The order is a step toward the rollback of federal oversight that Musk, who has fought bitterly with the Federal Aviation Administration over his space operations, and others have pushed for. Commercial rocket launches have grown exponentially more frequent in recent years.

Critics warn such a move could have dangerous consequences.

“It would not be reasonable for them to be rescinding regulations that are there to protect the public interest, and the public, from harm,” said Jared Margolis, a senior attorney for the Center for Biological Diversity, a nonprofit that works to protect animals and the environment. “And that’s my fear here: Are they going to change things in a way that puts people at risk, that puts habitats and wildlife at risk?”

The White House did not answer questions about the draft order.

“The Trump administration is committed to cementing America’s dominance in space without compromising public safety or national security,” said White House spokesperson Kush Desai. “Unless announced by President Trump, however, discussion about any potential policy changes should be deemed speculation.”

The order would give Trump even more direct control over the space industry’s chief regulator by turning the civil servant position leading the FAA’s Office of Commercial Space Transportation into a political appointment. The last head of the office and two other top officials recently took voluntary separation offers.

The order would also create a new adviser to the transportation secretary to shepherd in deregulation of the space industry.

The draft order comes as SpaceX is ramping up its ambitious project to build a reusable deep-space rocket to carry people to Earth’s orbit, the moon and eventually Mars. The rocket, called Starship, is the largest, most powerful ever built, standing 403 feet tall with its booster. The company has hit some milestones but has also been beset by problems, as three of the rockets launched from Texas this year have exploded—disrupting air traffic and raining debris on beaches and roads in the Caribbean and Gulf waters.

The draft order also seeks to restrict the authority of state coastal officials who have challenged commercial launch companies like SpaceX, documents show. It could lead to federal officials interfering with state efforts to enforce their environmental rules when they conflict with the construction or operation of spaceports.

Derek Brockbank, executive director for the Coastal States Organization, said the proposed executive order could ultimately force state commissions to prioritize spaceport infrastructure over other land uses, such as renewable energy, waterfront development, or coastal restoration, along the coastline. His nonprofit represents 34 coastal states and territories.

“It’s concerning that it could potentially undermine the rights of a state to determine how it wants its coast used, which was the very fundamental premise of the congressionally authorized Coastal Zone Management Act,” he said. “We shouldn’t see any president, no matter what their party is, coming in and saying, ‘This is what a state should prioritize or should do.’”

SpaceX is already suing the California Coastal Commission, accusing the agency of political bias and interference with the company’s efforts to increase the number of Falcon 9 rocket launches from Vandenberg Space Force Base. The reusable Falcon 9 is SpaceX’s workhorse rocket, ferrying satellites to orbit and astronauts to the International Space Station.

The changes outlined in the order would greatly benefit SpaceX, which launches far more rockets into space than any other company in the US. But it would also help rivals such as Jeff Bezos’ Blue Origin and California-based Rocket Lab. The companies have been pushing to pare down oversight for years, warning that the US is racing with China to return to the moon—in hopes of mining resources like water and rare earth metals and using it as a stepping stone to Mars—and could lose if regulations don’t allow US companies to move faster, said Dave Cavossa, president of the Commercial Space Federation, a trade group that represents eight launch companies, including SpaceX, Blue Origin, and Rocket Lab.

“It sounds like they’ve been listening to industry, because all of those things are things that we’ve been advocating for strongly,” Cavossa said when asked about the contents of the draft order.

Cavossa said he sees “some sort of environmental review process” continuing to take place. “What we’re talking about doing is right-sizing it,” he said.

He added, “We can’t handle a yearlong delay for launch licenses.”

The former head of the FAA’s commercial space office said at a Congressional hearing last September that the office took an average of 151 days to issue a new license during the previous 11 years.

Commercial space launches have boomed in recent years—from 26 in 2019 to 157 last year. With more than 500 total launches, mostly from Texas, Florida, and California, SpaceX has been responsible for the lion’s share, according to FAA data.

But the company has tangled with the FAA, which last year proposed fining it $633,000 for violations related to two of its launches. The FAA did not answer a question last week about the status of the proposed fine.

SpaceX, Blue Origin, Rocket Lab, and the FAA did not respond to requests for comment.

Currently, the FAA’s environmental reviews look at 14 types of potential impacts that include air and water quality, noise pollution, and land use, and provide details about the launches that are not otherwise available. They have at times drawn big responses from the public.

When SpaceX sought to increase its Starship launches in Texas from five to 25 a year, residents and government agencies submitted thousands of comments. Most of the nearly 11,400 publicly posted comments opposed the increase, a ProPublica analysis found. The FAA approved the increase anyway earlier this year. After conducting an environmental assessment for the May launch of SpaceX’s Starship Flight 9 from Texas, the FAA released documents that revealed as many as 175 airline flights could be disrupted and Turks and Caicos’ Providenciales International Airport would need to close during the launch.

In addition to seeking to cut short environmental reviews, the executive order would open the door for the federal government to rescind sections of the federal rule that seeks to keep the public safe during launches and reentries.

The rule, referred to as Part 450, was approved during Trump’s first term and aimed to streamline commercial space regulations and speed approvals of launches. But the rule soon fell out of favor with launch companies, which said the FAA didn’t provide enough guidance on how to comply and was taking too long to review applications.

Musk helped lead the charge. Last September, he told attendees at a conference in Los Angeles, “It really should not be possible to build a giant rocket faster than paper can move from one desk to another.” He called for the resignation of the head of the FAA, who stepped down as Trump took office.

Other operators have expressed similar frustration, and some members of Congress have signaled support for an overhaul. In February, Rep. Brian Babin, R-Texas, and Rep. Zoe Lofgren, D-Calif., signed a letter asking the Government Accountability Office to review the process for approving commercial launches and reentries.

In their letter, Babin and Lofgren wrote they wanted to understand whether the rules are “effectively and efficiently accommodating United States commercial launch and reentry operations, especially as the cadence and technological diversity of such operations continues to increase.

The draft executive order directs the secretary of transportation to “reevaluate, amend, or rescind” sections of Part 450 to “enable a diversified set of operators to achieve an increase in commercial space launch cadence and novel space activities by an order of magnitude by 2030.”

The order also directs the Department of Commerce to streamline regulation of novel space activity, which experts say could include things like mining or making repairs in space, that doesn’t fall under other regulations.

Brandon Roberts and Pratheek Rebala contributed data analysis.

This story originally appeared on ProPublica.

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Nearly 3,000 people are leaving NASA, and this director is one of them

You can add another name to the thousands of employees leaving NASA as the Trump administration primes the space agency for a 25 percent budget cut.

On Monday, NASA announced that Makenzie Lystrup will leave her post as director of the Goddard Space Flight Center on Friday, August 1. Lystrup has held the top job at Goddard since April 2023, overseeing a staff of more than 8,000 civil servants and contractor employees and a budget last year of about $4.7 billion.

These figures make Goddard the largest of NASA’s 10 field centers primarily devoted to scientific research and development of robotic space missions, with a budget and workforce comparable to NASA’s human spaceflight centers in Texas, Florida, and Alabama. Officials at Goddard manage the James Webb and Hubble telescopes in space, and Goddard engineers are assembling the Nancy Grace Roman Space Telescope, another flagship observatory scheduled for launch late next year.

“We’re grateful to Makenzie for her leadership at NASA Goddard for more than two years, including her work to inspire a Golden Age of explorers, scientists, and engineers,” Vanessa Wyche, NASA’s acting associate administrator, said in a statement.

Cynthia Simmons, Goddard’s deputy director, will take over as acting chief at the space center. Simmons started work at Goddard as a contract engineer 25 years ago.

Lystrup came to NASA from Ball Aerospace, now part of BAE Systems, where she managed the company’s work on civilian space projects for NASA and other federal agencies. Before joining Ball Aerospace, Lystrup earned a doctorate in astrophysics from University College London and conducted research as a planetary astronomer.

Formal dissent

The announcement of Lystrup’s departure from Goddard came hours after the release of an open letter to NASA’s interim administrator, Transportation Secretary Sean Duffy, signed by hundreds of current and former agency employees. The letter, titled the “The Voyager Declaration,” identifies what the signatories call “recent policies that have or threaten to waste public resources, compromise human safety, weaken national security, and undermine the core NASA mission.”

Nearly 3,000 people are leaving NASA, and this director is one of them Read More »

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As White House talks about impounding NASA funding, Congress takes the threat seriously

This year, given the recent action on the budget measures, it is possible that Congress could pass Appropriations legislation for most of the federal government, including NASA before October 1.

Certainly there is motivation to do so, because the White House and its Office of Management and Budget, led by Russ Vought, has indicated that in absence of Appropriations legislation it is planning to take measures that would implement the Presidents Budget Request, which set significantly lower spending levels for NASA and other federal agencies.

For example, as Ars reported earlier this month, the principal investigators of NASA science missions that White House seeks to kill have been told to create termination plans that could be implemented within three months, beginning as soon as October 1.

Whether there is a continuing resolution, or shutdown, then, the White House appears likely to go to court to implement its spending priorities at federal agencies, including NASA.

Congress acknowledges the threat

This week the Ranking Members of House committee with oversight over NASA raised the alarm publicly about this in a letter to Sean Duffy, the Secretary of Transportation who was recently named interim administrator of NASA as well.

NASA appears to be acting in accordance with a fringe, extremist ideology emanating from the White House Office of Management and Budget that asserts a right to impound funds appropriated by Congress for the sake of executive branch priorities. Moreover, it now appears that the agency intends to implement funding cuts that were never enacted by Congress in order to “align” the agency’s present-day budget with the Trump Administration’s slash-and-burn proposed budget for the next fiscal year, with seemingly no concern for the devastation that will be caused by mass layoffs, widespread program terminations, and the possible closure of critical centers and facilities. These decisions are wrong, and they are not yours to make.

The letter reminds Duffy that Congress sets the budget, and federal agencies work toward those budget levels. However, the legislators say, NASA is moving ahead with funding freezes for various programs reducing employees across the agency. Approximately 2,700 employees have left the agency since the beginning of the Trump Administration.

As White House talks about impounding NASA funding, Congress takes the threat seriously Read More »

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After a partly successful test flight, European firm eyes space station mission

Last month, the parachutes on Hélène Huby’s small spacecraft failed to deploy, and the vehicle and its cargo crashed into the ocean on Earth.

It was both a success and a failure.

The success was that after Huby founded The Exploration Company in Europe, she managed to move nimbly with the “Mission Possible” spacecraft such that it cost less than $25 million to build and reached space in less than three years. The vehicle ticked off a number of successes in spaceflight before making a controlled descent through the atmosphere.

But at 26 km above the planet, as the spacecraft slowed to Mach one, The Exploration Company lost contact. Huby was not sure how this loss would be received in Europe, where failures in spaceflight have not been traditionally well-tolerated.

“What was interesting is the feedback I got in Europe,” Huby said in an interview this week at the company’s offices in Houston. “The German Space Agency, the French space agency, the European Space Agency said, OK, that’s a great achievement. For the time and money we spent, performing 80 percent of that mission was a good investment.”

No drop tests

After the spacecraft was lost on June 24, the company established an independent investigation team. Huby said it is “99 percent” confirmed there was a problem with the deployment of the parachutes, either the drogue chutes or the main parachutes. The fault was not with the provider of the parachutes themselves, US-based Airborne Systems, but the company’s mechanism, she said.

To save time and money, The Exploration Company did not conduct any drop tests. Such a campaign would have added millions of dollars to a program that was trying to be lean, plus a year of schedule to a mission attempting to move fast.

“We made a mistake, basically, to underestimate the risks,” she said. In retrospect, Huby added, the company could have done more testing on the ground.

Now the firm faces a big decision: How to proceed from here. One option is building another small spacecraft, similar to Mission Possible, for testing purposes. But there is limited commonality in the parachute system for this vehicle and the larger Nyx spacecraft the company is building for operational missions. So if the Mission Possible parachutes were to work, that would not guarantee success for Nyx.

After a partly successful test flight, European firm eyes space station mission Read More »

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Rocket Report: SpaceX won’t land at Johnston Atoll; new North Sea launch site


All the news that’s fit to lift

“Europe is seizing the opportunity to lead.”

NASA astronauts Mike Fincke (left) and Zena Cardman (right), the pilot and commander of NASA’s SpaceX Crew-11 mission to the International Space Station, view a Falcon 9 rocket ahead of their spaceflight. Credit: SpaceX

Welcome to Edition 8.03 of the Rocket Report! We are at an interesting stage in Europe, with its efforts to commercialize spaceflight. Finally, it seems the long-slumbering continent is waking up to the need to leverage private capital to drive down the costs of space access, and we are seeing more investment flow into European companies. But it is critical that European policymakers make strategic investments across the industry or companies like PLD Space, which outlined big plans this week, will struggle to get off the launch pad.

As always, we welcome reader submissions, and if you don’t want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets, as well as a quick look ahead at the next three launches on the calendar.

Avio celebrates freedom from Arianespace. Representatives from Italy, Germany, and France met at the European Space Agency headquarters last week to sign the Launcher Exploitation Declaration, which officially began the transfer of Vega C launch operation responsibilities from Arianespace to the rocket’s builder, Avio, European Spaceflight reports. “It is a historic step that reinforces our nation’s autonomy in access to space and assigns us a strategic responsibility towards Europe,” said Avio CEO Giulio Ranzo. “We are ready to meet this challenge with determination, and we are investing in technologies, expertise, and infrastructure to ensure a competitive service.”

A breaking of long-term partnerships … In addition to securing control over the full exploitation of the Vega launch vehicle family, Italy, through Avio, is also investing in what comes next. The country has committed more than 330 million euros to the development of the MR60 methalox rocket engine and two demonstrator vehicles. These, along with the MR10 engine being developed under the Vega E programme, will support Avio’s preparation of a future reusable launch vehicle. Historically, France, Germany, and Italy have worked together on European launch vehicles. This appears to be another step in breaking up that long-term partnership toward more nationalistic efforts.

PLD Space outlines grand ambitions. PLD Space, Spain’s sole contestant in the European Launcher Challenge, unveiled its long-term strategy at the company’s Industry Days event this week, Payload reports. The company is targeting a production rate of 32 Miura 5 launchers annually by 2030. To achieve this output, PLD plans to deepen its vertical integration, consolidate its supplier network, and begin to serialize its manufacturing process beginning in 2027.

Building up the supply chain … The company’s production plans also call for the parallel development of Miura Next, a heavy-lift vehicle capable of bringing 13 tons to orbit. However, the company will start with the Miura 5 vehicle, which PLD expects to launch for the first time from French Guiana in 2026. Since the beginning of 2024, PLD has invested a total of 50 million euros in its Miura 5 supply chain, consisting of 397 industrial partners, many of which are located in Spain and other European countries.  These plans are great, but sooner or later, the 14-year-old company needs to start putting rockets in space. (submitted by EllPeaTea)

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New consortium will study space plane. A UK-based space and defense consultant group, Frazer-Nash, will lead a program to design a vehicle and its integrated systems with the goal of building and flying a Mach 5-capable aircraft at the edge of space by early 2031. This so-called INVICTUS program was funded with a 7 million-euro grant from the European Space Agency and is seen as a stepping stone toward developing a reusable space plane that takes off and lands horizontally from a runway.

Seeking to lead a new era of flight … Over 12 months, INVICTUS has been tasked to deliver the concept and elements of the preliminary design of the full flight system. It will attempt to demonstrate the efficacy of hydrogen-fueled, precooled air-breathing propulsion at hypersonic speeds, technology that will ultimately enable horizontal take-off. “With INVICTUS, Europe is seizing the opportunity to lead in technologies that will redefine how we move across the planet and reach beyond it,” said Tommaso Ghidini, head of the Mechanical Department at the European Space Agency. (submitted by Jid)

ESA backs North Sea launch site. A private company developing a launch site in the North Sea, EuroSpaceport, has secured support from the European Space Agency. The company, founded five years ago, is developing a sea-based launch platform built on a repurposed offshore wind turbine service vessel, European Spaceflight reports. Rockets are envisioned to launch from a position 50 to 100 km offshore from the port of Esbjerg, in Denmark.

Seeing the forest for the trees … On Wednesday, EuroSpaceport announced that it had signed an agreement with the European Space Agency and Polish rocket builder SpaceForest to support the first launch from its Spaceport North Sea platform. The company will receive support from the agency through its Boost! Program. SpaceForest has been a recipient of Boost! funding, receiving 2.4 million euros in October 2024. SpaceForest said the mission will be used to verify the launch procedures of its Perun rocket under nominal suborbital conditions. (submitted by EllPeaTea)

Amazon and SpaceX, best frenemies? Maybe not, but for the time being, they appear to be friends of convenience. A Falcon 9 rocket launched from Florida’s Space Coast early on Wednesday with a batch of Internet satellites for Amazon’s Project Kuiper network, thrusting a rival one step closer to competing with SpaceX’s Starlink broadband service. With this launch, Amazon now has 78 Kuiper satellites in orbit, Ars reports. The full Kuiper constellation will consist of 3,232 satellites to provide broadband Internet service to most of the populated world, bringing Amazon in competition with SpaceX’s Starlink network.

Launch is not cheap … Kuiper is an expensive undertaking, estimated at between $16.5 billion and $20 billion by the industry analytics firm Quilty Space. Quilty has concluded that Amazon is spending $10 billion on launch alone, exceeding the company’s original cost estimate for the entire program. Amazon has booked more than 80 launches to deploy the Kuiper constellation, but the company didn’t turn to SpaceX until it had to. A shareholder lawsuit filed in 2023 accused Amazon founder Jeff Bezos and the company’s board of directors of breaching their “fiduciary duty” by not considering SpaceX as an option for launching Kuiper satellites. The plaintiffs in the lawsuit alleged Amazon didn’t consider the Falcon 9 due to an intense and personal rivalry between Bezos and SpaceX founder Elon Musk. Amazon bowed to the allegations and announced a contract with SpaceX for three Falcon 9 launches in December 2023 to provide “additional capacity” for deploying the Kuiper network.

NASA targets end of July for Crew-11. NASA said Monday that it and SpaceX were targeting July 31 for the flight of SpaceX’s Crew-11 mission to the orbiting outpost, Spaceflight Now reports. The mission is led by NASA astronaut Zena Cardman. She will be flying along with fellow NASA astronaut Mike Fincke, Japan Aerospace Exploration Agency (JAXA) astronaut Kimiya Yui and Roscosmos cosmonaut Oleg Platonov.

Pushing Dragon reuse … The mission was moved up from its previously planned August launch window to create more room in the manifest for the arrival of the Cargo Dragon flying the CRS-33 mission. That Dragon will perform a boost of the space station as a demonstration of some of the capabilities SpaceX will use on its US Deorbit Vehicle currently in work. Crew-11 will fly to the orbiting outpost on Crew Dragon Endeavour, which will be its sixth trip to the ISS. This will be the first Crew Dragon spacecraft to fly for a sixth time.

SpaceX won’t use Johnston Atoll for rocket cargo tests. Johnston Atoll, an unincorporated US territory and Pacific island wildlife refuge with a complicated military history, will no longer become a SpaceX reusable rocket test site, Popular Science reports. “The Department of the Air Force has elected to hold the preparation of the Johnston Atoll Environmental Assessment for a proposed rocket cargo landing demonstration on Johnston Atoll in abeyance while the service explores alternative options for implementation,” Air Force spokesperson Laurel Falls said.

Taking a toll on the atoll … Located roughly 860 miles southwest of Hawaii, Johnston Atoll has served as a base for numerous US military operations for over 90 years. Despite this, the atoll remains a home for 14 tropical bird species as part of the Pacific Remote Islands Marine National Monument. The site had been under consideration for tests as part of a military program to deliver cargo around the planet, using suborbital missions on rocket such as SpaceX’s Starship vehicle. The Johnston Atoll plans included the construction of two landing pads that were met with public backlash from wildlife experts and indigenous representatives. (submitted by Tfargo04)

Blue Origin confirms ESCAPADE is up next. On Thursday, Blue Origin said on social media that the second launch of its New Glenn rocket will carry NASA’s ESCAPADE mission as its primary payload. This launch will support ESCAPADE’s science objectives as the twin spacecraft progress on their journey to the Red Planet. Also onboard is a technology demonstration from @Viasat in support of @NASASpaceOps’ Communications Services Project.

Left unsaid was when the launch will occur … The social media post confirms a report from Ars in June, which said the ESCAPADE spacecraft was up next on New Glenn. Previously, the company has said this second launch will take place no earlier than August 15. However, that is less than one month away. Late September is probably the earliest realistic launch date, with October or November more likely for the second flight of the company’s large rocket.

Next three launches

July 19: Falcon 9 | Starlink 17-3 | Vandenberg Space Force Base, California | 03: 44 UTC

July 21: Falcon 9 | O3b mPOWER 9 & 10 | Cape Canaveral Space Force Station, Florida | 21: 00 UTC

July 22: Falcon 9 | NASA’s Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites | Vandenberg Space Force Base, California | 18: 05 UTC

Photo of Eric Berger

Eric Berger is the senior space editor at Ars Technica, covering everything from astronomy to private space to NASA policy, and author of two books: Liftoff, about the rise of SpaceX; and Reentry, on the development of the Falcon 9 rocket and Dragon. A certified meteorologist, Eric lives in Houston.

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the-iss-is-nearing-retirement,-so-why-is-nasa-still-gung-ho-about-starliner?

The ISS is nearing retirement, so why is NASA still gung-ho about Starliner?


NASA is doing all it can to ensure Boeing doesn’t abandon the Starliner program.

Boeing’s Starliner spacecraft atop a United Launch Alliance Atlas V rocket before a test flight in 2019. Credit: NASA/Joel Kowsky

Boeing’s Starliner spacecraft atop a United Launch Alliance Atlas V rocket before a test flight in 2019. Credit: NASA/Joel Kowsky

After so many delays, difficulties, and disappointments, you might be inclined to think that NASA wants to wash its hands of Boeing’s troubled Starliner spacecraft.

But that’s not the case.

The manager of NASA’s commercial crew program, Steve Stich, told reporters Thursday that Boeing and its propulsion supplier, Aerojet Rocketdyne, are moving forward with several changes to the Starliner spacecraft to resolve problems that bedeviled a test flight to the International Space Station (ISS) last year. These changes include new seals to plug helium leaks and thermal shunts and barriers to keep the spacecraft’s thrusters from overheating.

Boeing, now more than $2 billion in the hole to pay for all Starliner’s delays, is still more than a year away from executing on its multibillion-dollar NASA contract and beginning crew rotation flights to the ISS. But NASA officials say Boeing remains committed to Starliner.

“We really are working toward a flight as soon as early next year with Starliner, and then ultimately, our goal is to get into crew rotation flights with Starliner,” Stich said. “And those would start no earlier than the second crew rotation slot at the end of next year.”

That would be 11 years after Boeing officials anticipated the spacecraft would enter operational service for NASA when they announced the Starliner program in 2010.

Decision point

The next Starliner flight will probably transport only cargo to the ISS, not astronauts. But NASA hasn’t made any final decisions on the matter. The agency has enough crew rotation missions booked to fly on SpaceX’s Dragon spacecraft to cover the space station’s needs until well into 2027 or 2028.

“I think there are a lot of advantages, I would say, to fly the cargo flight first,” Stich said. “If we really look at the history of Starliner and Dragon, I think Dragon benefited a lot from having earlier [cargo] flights before the crew contract was let for the space station.”

One drawback of flying a Starliner cargo mission is that it will use up one of United Launch Alliance’s remaining Atlas V rockets currently earmarked for a future Starliner crew launch. That means Boeing would have to turn to another rocket to accomplish its full contract with NASA, which covers up to six crew missions.

While Boeing says Starliner can launch on several different rockets, the difficulty of adapting the spacecraft to a new launch vehicle, such as ULA’s Vulcan, shouldn’t be overlooked. Early in Starliner’s development, Boeing and ULA had to overcome an issue with unexpected aerodynamic loads discovered during wind tunnel testing. This prompted engineers to design an aerodynamic extension, or skirt, to go underneath the Starliner spacecraft on top of its Atlas V launcher.

Starliner has suffered delays from the beginning. A NASA budget crunch in the early 2010s pushed back the program about two years, but the rest of the schedule slips have largely fallen on Boeing’s shoulders. The setbacks included a fuel leak and fire during a critical ground test, parachute problems, a redesign to accommodate unanticipated aerodynamic forces, and a computer timing error that cut short Starliner’s first attempt to reach the space station in 2019.

This all culminated in the program’s first test flight with astronauts last summer. But after running into helium leaks and overheating thrusters, the mission ended with Starliner returning to Earth empty, while the spacecraft’s two crew members remained on the International Space Station until they could come home on a SpaceX Dragon spacecraft this year.

The outcome was a stinging disappointment for Boeing. Going into last year’s crew test flight, Boeing appeared to be on the cusp of joining SpaceX and finally earning revenue as one of NASA’s certified crew transportation providers for the ISS.

For several months, Boeing officials were strikingly silent on Starliner’s future. The company declined to release any statements on their long-term commitment to the program, and a Boeing program manager unexpectedly withdrew from a NASA press conference marking the end of the Starliner test flight last September.

Kelly Ortberg, Boeing’s president and CEO, testifies before the Senate Commerce, Science, and Transportation Committee on April 2, 2025, in Washington, DC. Credit: Win McNamee/Getty Images

But that has changed in the last few months. Kelly Ortberg, who took over as Boeing’s CEO last year, told CNBC in April that the company planned “more missions on Starliner” and said work to overcome the thruster issues the spacecraft encountered last year is “pretty straightforward.”

“We know what the problems were, and we’re making corrective actions,” Ortberg said. “So, we hope to do a few more flights here in the coming years.”

Task and purpose

NASA officials remain eager for Starliner to begin these regular crew rotation flights, even as its sole destination, the ISS, enters its sunset years. NASA and its international partners plan to decommission and scuttle the space station in 2030 and 2031, more than 30 years after the launch of the lab’s first module.

NASA’s desire to bring Starliner online has nothing to do with any performance issues with SpaceX, the agency’s other commercial crew provider. SpaceX has met or exceeded all of NASA’s expectations in 11 long-duration flights to the ISS with its Dragon spacecraft. Since its first crew flight in 2020, SpaceX has established a reliable cadence with Dragon missions serving NASA and private customers.

However, there are some questions about SpaceX’s long-term plans for the Dragon program, and those concerns didn’t suddenly spring up last month, when SpaceX founder and chief executive Elon Musk suggested on X that SpaceX would “immediately” begin winding down the Dragon program. The suggestion came as Musk and President Donald Trump exchanged threats and insults on social media amid a feud as the one-time political allies had a dramatic falling out months into Trump’s second term in the White House.

In a subsequent post on X, Musk quickly went back on his threat to soon end the Dragon program. SpaceX officials participating in NASA press conferences in the last few weeks have emphasized the company’s dedication to human spaceflight without specifically mentioning Dragon. SpaceX’s fifth and final human-rated Dragon capsule debuted last month on its first flight to the ISS.

“I would say we’re pretty committed to the space business,” said Bill Gerstenmaier, SpaceX’s vice president of build and flight reliability. “We’re committed to flying humans in space and doing it safely.”

There’s a kernel of truth behind Musk’s threat to decommission Dragon. Musk has long had an appetite to move on from the Dragon program and pivot more of SpaceX’s resources to Starship, the company’s massive next-generation rocket. Starship is envisioned by SpaceX as an eventual replacement for Dragon and the Falcon 9 launcher.

A high-resolution commercial Earth-imaging satellite owned by Maxar captured this view of the International Space Station on June 7, 2024, with Boeing’s Starliner capsule docked at the lab’s forward port (lower right). Credit: Satellite image (c) 2024 Maxar Technologies

NASA hopes commercial space stations can take over for the ISS after its retirement, but there’s no guarantee SpaceX will still be flying Dragon in the 2030s. This injects some uncertainty into plans for commercial space stations.

One possible scenario is that, sometime in the 2030s, the only options for transporting people to and from commercial space stations in low-Earth orbit could be Starliner and Starship. We’ll discuss the rationale for this scenario later in this story.

While the cost of a seat on SpaceX’s Dragon is well known, there’s low confidence in the price of a ticket to low-Earth orbit on Starliner or Starship. What’s more, some of the commercial outposts may be incompatible with Starship because of its enormous mass, which could overcome the ability of a relatively modest space station to control its orientation. NASA identified this as an issue with its Gateway mini-space station in development to fly in orbit around the Moon.

It’s impossible to predict when SpaceX will pull the plug on Dragon. The same goes with Boeing and Starliner. But NASA and other customers are interested in buying more Dragon flights.

If SpaceX can prove Starship is safe enough to launch and land with people onboard, Dragon’s days will be numbered. But Starship is likely at least several years from being human-rated for flights to and from low-Earth orbit. NASA’s contract with SpaceX to develop a version of Starship to land astronauts on the Moon won’t require the ship to be certified for launches and landings on Earth. In some ways, that’s a more onerous challenge than the Moon mission because of the perils of reentering Earth’s atmosphere, which Starship won’t need to endure for a lunar landing, and the ship’s lack of a launch abort system.

Once operational, Starship is designed to carry significantly more cargo and people than Falcon 9 and Dragon, but it’s anyone’s guess when it might be ready for crew missions. Until then, if SpaceX wants to have an operational human spaceflight program, it’s Dragon or bust.

For the International Space Station, it’s also Dragon or bust, at least until Boeing gets going. SpaceX’s capsules are the only US vehicles certified to fly to space with NASA astronauts, and any more US government payments to Russia to launch Americans on Soyuz missions would be politically unpalatable.

From the start of the commercial crew program, NASA sought two contractors providing their own means of flying to and from the ISS. The main argument for this “dissimilar redundancy” was to ensure NASA could still access the space station in the event of a launch failure or some other technical problem. The same argument could be made now that NASA needs two options to avoid being at the whim of one company’s decisions.

Stretching out

All of this is unfolding as the Trump administration seeks to slash funding for the International Space Station, cut back on the lab’s research program, and transition to “minimal safe operations” for the final few years of its life. Essentially, the space station would limp to the finish line, perhaps with a smaller crew than the seven-person staff living and working in it today.

At the end of this month, SpaceX is scheduled to launch the Crew-11 mission—the 12th Dragon crew mission for NASA and the 11th fully operational crew ferry flight to the ISS. Two Americans, one Japanese astronaut, and a Russian cosmonaut will ride to the station for a stay of at least six months.

NASA’s existing contract with SpaceX covers four more long-duration flights to the space station with Dragon, including the mission set to go on July 31.

One way NASA can save money in the space station’s budget is by simply flying fewer missions. Stich said Thursday that NASA is working with SpaceX to extend the Dragon spacecraft’s mission duration limit from seven months to eight months. The recertification of Dragon for a longer mission could be finished later this year, allowing NASA to extend Crew-11’s stay at the ISS if needed. Over time, longer stays mean fewer crew rotation missions.

“We can extend the mission in real-time as needed as we better understand… the appropriations process and what that means relative to the overall station manifest,” Stich said.

Boeing’s Starliner spacecraft backs away from the International Space Station on September 6, 2024, without its crew. Credit: NASA

Boeing’s fixed-price contract with NASA originally covered an unpiloted test flight of Starliner, a demonstration flight with astronauts, and then up to six operational missions delivering crews to the ISS. But NASA has only given Boeing the “Authority To Proceed” for three of its six potential operational Starliner missions. This milestone, known as ATP, is a decision point in contracting lingo where the customer—in this case, NASA—places a firm order for a deliverable. NASA has previously said it awards these task orders about two to three years prior to a mission’s launch.

If NASA opts to go to eight-month missions on the ISS with Dragon and Starliner, the agency’s firm orders for three Boeing missions and four more SpaceX crew flights would cover the agency’s needs into early 2030, not long before the final crew will depart the space station.

Stich said NASA officials are examining their options. These include whether NASA should book more crew missions with SpaceX, authorize Boeing to prepare for additional Starliner flights beyond the first three, or order no more flights at all.

“As we better understand the budget and better understand what’s in front of us, we’re working through that,” Stich said. “It’s really too early to speculate how many flights we’ll fly with each provider, SpaceX and Boeing.”

Planning for the 2030s

NASA officials also have an eye for what happens after 2030. The agency has partnered with commercial teams led by Axiom, Blue Origin, and Voyager Technologies on plans for privately owned space stations in low-Earth orbit to replace some of the research capabilities lost with the end of the ISS program.

The conventional wisdom goes that these new orbiting outposts will be less expensive to operate than the ISS, making them more attractive to commercial clients, ranging from pharmaceutical research and in-space manufacturing firms to thrill-seeking private space tourists. NASA, which seeks to maintain a human presence in low-Earth orbit as it turns toward the Moon and Mars, will initially be an anchor customer until the space stations build up more commercial demand.

These new space stations will need a way to receive cargo and visitors. NASA wants to preserve the existing commercial cargo and crew transport systems so they’re available for commercial space stations in the 2030s. Stich said NASA is looking at transferring the rights for any of the agency’s commercial crew missions that don’t fly to ISS over to the commercial space stations. Among NASA’s two commercial crew providers, it currently looks more likely that Boeing’s contract will have unused capacity than SpaceX’s when the ISS program ends.

This is a sweetener NASA could offer to its stable of private space station developers as they face other hurdles in getting their hardware off the ground. It’s unclear whether a business case exists to justify the expense of building and operating a commercial outpost in orbit or if the research and manufacturing customers that could use a private space station might find a cheaper option in robotic flying laboratories, such as those being developed by Varda Space Industries.

A rendering of Voyager’s Starlab space station. Credit: Voyager Space

NASA’s policies haven’t helped matters. Analysts say NASA’s financial support for private space station developers has lagged, and the agency’s fickle decision-making on when to retire the International Space Station has made private fundraising more difficult. It’s not a business for the faint-hearted. For example, Axiom has gone through several rounds of layoffs in the last year.

The White House’s budget request for fiscal year 2026 proposes a 25 percent cut to NASA’s overall budget, but the funding line for commercial space stations is an area marked for an increase. Still, there’s a decent chance that none of the proposed commercial outposts will be flying when the ISS crashes back to Earth. In that event, China would be the owner and operator of the only space station in orbit.

At least at first, transportation costs will be the largest expense for any company that builds and operates a privately owned space station. It costs NASA about 40 percent more each year to ferry astronauts and supplies to and from the ISS than it does to operate the space station. For a smaller commercial outpost with reduced operating costs, the gap will likely be even wider.

If Boeing can right the ship with Starliner and NASA offers a few prepaid crew missions to private space station developers, the money saved could help close someone’s business case and hasten the launch of a new era in commercial spaceflight.

Photo of Stephen Clark

Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

The ISS is nearing retirement, so why is NASA still gung-ho about Starliner? Read More »

congress-moves-to-reject-bulk-of-white-house’s-proposed-nasa-cuts

Congress moves to reject bulk of White House’s proposed NASA cuts

Fewer robots, more humans

The House version of NASA’s fiscal year 2026 budget includes $9.7 billion for exploration programs, a roughly 25 percent boost over NASA’s exploration budget for 2025, and 17 percent more than the Trump administration’s request in May. The text of the House bill released publicly doesn’t include any language explicitly rejecting the White House’s plan to terminate the SLS and Orion programs after two more missions.

Instead, it directs NASA to submit a five-year budget profile for SLS, Orion, and associated ground systems to “ensure a crewed launch as early as possible.” A five-year planning budget seems to imply that the House committee wants SLS and Orion to stick around. The White House budget forecast zeros out funding for both programs after 2028.

The House also seeks to provide more than $4.1 billion for NASA’s space operations account, a slight cut from 2025 but well above the White House’s number. Space operations covers programs like the International Space Station, NASA’s Commercial Crew Program, and funding for new privately owned space stations to replace the ISS.

Many of NASA’s space technology programs would also be salvaged in the House budget, which allocates $913 million for tech development, a reduction from the 2025 budget but still an increase over the Trump administration’s request.

The House bill’s cuts to science and space technology, though more modest than those proposed by the White House, would still likely result in cancellations and delays for some of NASA’s robotic space missions.

Rep. Grace Meng (D-NY), the senior Democrat on the House subcommittee responsible for writing NASA’s budget, called out the bill’s cut to the agency’s science portfolio.

“As other countries are racing forward in space exploration and climate science, this bill would cause the US to fall behind by cutting NASA’s account by over $1.3 billion,” she said Tuesday.

Lawmakers reported the Senate spending bill to the full Senate Appropriations Committee last week by voice vote. Members of the House subcommittee advanced their bill to the full committee Tuesday afternoon by a vote of 9-6.

The budget bills will next be sent to the full appropriations committees of each chamber for a vote and an opportunity for amendments, before moving on to the floor for a vote by all members.

It’s still early in the annual appropriations process, and a final budget bill is likely months away from passing both houses of Congress and heading to President Donald Trump’s desk for signature. There’s no guarantee Trump will sign any congressional budget bill, or that Congress will finish the appropriations process before this year’s budget runs out on September 30.

Congress moves to reject bulk of White House’s proposed NASA cuts Read More »

‘not-that-into-peace-doves’:-the-apollo-soyuz-patch-nasa-rejected

‘Not that into peace doves’: The Apollo-Soyuz patch NASA rejected

a black and white ink drawing of a man carrying an oversized space mission patch running towards a launching rocket

Paul Calle’s July 1975 cartoon poking fun at his own rejected mission patch for the joint Apollo-Soyuz Test Project. Credit: Calle Space Art

Rejects and revivals

Calle’s patch design was not the only one ruled out by NASA’s officials.

At first, Stafford, Brand, and Slayton chose a design from a contest among the US space program’s workforce. The winner, Jean Pinataro of North American Rockwell (the prime contractor for the Apollo command module), came up with a concept that the astronauts liked, but the agency’s leaders rejected it for not having enough “international significance” (unofficially, it was also said to be “cartoonish”).

That led to NASA accepting the cost of hiring an artist from the NASA art program and Calle being invited to offer his ideas. It also resulted in the patch that flew.

When Calle stepped away, the decision was made to repurpose the work of Bob McCall, an artist who had designed the Apollo 17 mission patch and in 1974 had painted the scene of the Apollo and Soyuz spacecraft nearing a docking. McCall would go on to create similar art for a pair of postage stamps issued in the United States and the Soviet Union, while Pinataro adapted McCall’s original painting as the central image of the US ASTP emblem.

The cosmonauts had their own design—in fact, it was the first Russian mission patch to involve the crew’s input—but wore both their own and the US patch during their six days in space.

five colorful embroidered space patches each related to the 1975 Apollo -Soyuz Test Project

Apollo-Soyuz Test Project (ASTP) patches, from top left to right: 2021 embroidered replica of Jean Pinataro’s original design; the Soviet Soyuz 18 crew patch; the Apollo-Soyuz Test Project crew patch; souvenir ASTP program patch; and ASTP program patch. Credit: AB Emblem/Roscosmos/collectSPACE.com

Today, 50 years later, the McCall-inspired design, the cosmonauts’ patch, and the Apollo-Soyuz program insignia are used interchangeably to represent the mission. Calle’s designs have been largely forgotten but are now getting a revival for the golden anniversary.

“I wanted to reimagine them. Not redo them, but bring them to life,” said Chris.

Working with a fellow artist Tim Gagnon, who created a number of the mission patches worn by space shuttle and International Space Station crews, Chris has begun the process of producing a limited number of embroidered patches based on his and his late father’s ideas.

Chris primarily focused on Calle’s dove and olive branch design.

“It certainly keeps to the spirit of my dad’s original idea,” Chris said.

Chris Calle asks readers to contact him via his website to be informed about when the limited-edition Apollo-Soyuz patches are available.

Click through to collectSPACE to see more of Paul Calle’s original designs and the reimagined versions by Chris Calle and Tim Gagnon.

‘Not that into peace doves’: The Apollo-Soyuz patch NASA rejected Read More »

we-saw-the-heart-of-pluto-10-years-ago—it’ll-be-a-long-wait-to-see-the-rest

We saw the heart of Pluto 10 years ago—it’ll be a long wait to see the rest


A 50-year wait for a second mission wouldn’t be surprising. Just ask Uranus and Neptune.

Four images from New Horizons’ Long Range Reconnaissance Imager (LORRI) were combined with color data from the spacecraft’s Ralph instrument to create this enhanced color global view of Pluto. Credit: NASA/Johns Hopkins University/SWRI

NASA’s New Horizons spacecraft got a fleeting glimpse of Pluto 10 years ago, revealing a distant world with a picturesque landscape that, paradoxically, appears to be refreshing itself in the cold depths of our Solar System.

The mission answered numerous questions about Pluto that have lingered since its discovery by astronomer Clyde Tombaugh in 1930. As is often the case with planetary exploration, the results from New Horizons’ flyby of Pluto on July 14, 2015, posed countless more questions. First and foremost, how did such a dynamic world come to be so far from the Sun?

For at least the next few decades, the only resources available for scientists to try to answer these questions will be either the New Horizons mission’s archive of more than 50 gigabits of data recorded during the flyby, or observations from billions of miles away with powerful telescopes on the ground or space-based observatories like Hubble and James Webb.

That fact is becoming abundantly clear. Ten years after the New Horizons encounter, there are no missions on the books to go back to Pluto and no real prospects for one.

A mission spanning generations

In normal times, with a stable NASA budget, scientists might get a chance to start developing another Pluto mission in perhaps 10 or 20 years, after higher-priority missions like Mars Sample Return, a spacecraft to orbit Uranus, and a probe to orbit and land on Saturn’s icy moon Enceladus. In that scenario, perhaps a new mission could reach Pluto and enter orbit before the end of the 2050s.

But these aren’t normal times. The Trump administration has proposed cutting NASA’s science budget in half, jeopardizing not only future missions to explore the Solar System but also threatening to shut down numerous operating spacecraft, including New Horizons itself as it speeds through an uncharted section of the Kuiper Belt toward interstellar space.

The proposed cuts are sapping morale within NASA and the broader space science community. If implemented, the budget reductions would affect more than NASA’s actual missions. They would also slash NASA’s funding available for research, eliminating grants that could pay for scientists to analyze existing data stored in the New Horizons archive or telescopic observations to peer at Pluto from afar.

The White House maintains funding for newly launched missions like Europa Clipper and an exciting mission called Dragonfly to soar through the skies of Saturn’s moon Titan. Instead, the Trump administration’s proposed budget, which still must be approved by Congress, suggests a reluctance to fund new missions exploring anything beyond the Moon or Mars, where NASA would focus efforts on human exploration and bankroll an assortment of commercial projects.

NASA’s New Horizons spacecraft undergoing launch preparations at Kennedy Space Center, Florida, in September 2005. Credit: NASA

In this environment, it’s difficult to imagine the development of a new Pluto mission to begin any time in the next 20 years. Even if Congress or a future presidential administration restores NASA’s planetary science budget, a Pluto mission wouldn’t be near the top of the agency’s to-do list.

The National Academies’ most recent decadal survey prioritized Mars Sample Return, a Uranus orbiter, and an Enceladus “Orbilander” mission in their recommendations to NASA’s planetary science program through 2032. None of these missions has a realistic chance to launch by 2032, and it seems more likely than not that none of them will be in any kind of advanced stage of development by then.

The panel of scientists participating in the latest decadal survey—released in 2022—determined that a second mission to Pluto did not merit a technical risk and cost evaluation report, meaning it wasn’t even shortlisted for consideration as a science priority for NASA.

There’s a broad consensus in the scientific community that a follow-up mission to Pluto should be an orbiter, and not a second flyby. New Horizons zipped by Pluto at a relative velocity of nearly 31,000 mph (14 kilometers per second), flying as close as 7,750 miles (12,500 kilometers).

At that range and velocity, the spacecraft’s best camera was close enough to resolve something the size of a football field for less than an hour. Pluto was there, then it was gone. New Horizons only glimpsed half of Pluto at decent resolution, but what it saw revealed a heart-shaped sheet of frozen nitrogen and methane with scattered mountains of water ice, all floating on what scientists believe is likely a buried ocean of liquid water.

Pluto must harbor a wellspring of internal heat to keep from freezing solid, something researchers didn’t anticipate before the arrival of New Horizons.

New Horizons revealed Pluto as a mysterious world with icy mountains and very smooth plains. Credit: NASA

So, what is Pluto’s ocean like? How thick are Pluto’s ice sheets? Are any of Pluto’s suspected cryovolcanoes still active today? And, what secrets are hidden on the other half of Pluto?

These questions, and more, could be answered by an orbiter. Some of the scientists who worked on New Horizons have developed an outline for a conceptual mission to orbit Pluto. This mission, named Persephone for the wife of Pluto in classical mythology, hasn’t been submitted to NASA as a real proposal, but it’s worth illustrating the difficulties in not just reaching Pluto, but maneuvering into orbit around a dwarf planet so far from the Earth.

Nuclear is the answer

The initial outline for Persephone released in 2020 called for a launch in 2031 on NASA’s Space Launch System Block 2 rocket with an added Centaur kick stage. Again, this isn’t a realistic timeline for such an ambitious mission, and the rocket selected for this concept doesn’t exist. But if you assume Persephone could launch on a souped-up super heavy-lift SLS rocket in 2031, it would take more than 27 years for the spacecraft to reach Pluto before sliding into orbit in 2058.

Another concept study led by Alan Stern, also the principal investigator on the New Horizons mission, shows how a future Pluto orbiter could reach its destination by the late 2050s, assuming a launch on an SLS rocket around 2030. Stern’s concept, called the Gold Standard, would reserve enough propellant to leave Pluto and go on to fly by another more distant object.

Persephone and Gold Standard both assume a Pluto-bound spacecraft can get a gravitational boost from Jupiter. But Jupiter moves out of alignment from 2032 until the early 2040s, adding a decade or more to the travel time for any mission leaving Earth in those years.

It took nine years for New Horizons to make the trip from Earth to Pluto, but the spacecraft was significantly smaller than an orbiter would need to be. That’s because an orbiter has to carry enough power and fuel to slow down on approach to Pluto, allowing the dwarf planet’s weak gravity to capture it into orbit. A spacecraft traveling too fast, without enough fuel, would zoom past Pluto just like New Horizons.

The Persephone concept would use five nuclear radioisotope power generators and conventional electric thrusters, putting it within reach of existing technology. A 2020 white paper authored by John Casani, a longtime project manager at the Jet Propulsion Laboratory who died last month, showed the long-term promise of next-generation nuclear electric propulsion.

A relatively modest 10-kilowatt nuclear reactor to power electric thrusters would reduce the flight time to Pluto by 25 to 30 percent, while also providing enough electricity to power a radio transmitter to send science data back to Earth at a rate four times faster, according to the mission study report on the Persephone concept.

However, nuclear electric propulsion technologies are still early in the development phase, and Trump’s budget proposal also eliminates any funding for nuclear rocket research.

A concept for a nuclear electric propulsion system to power a spacecraft toward the outer Solar System. Credit: NASA/JPL-Caltech

A rocket like SpaceX’s Starship might eventually be capable of accelerating a probe into the outer Solar System, but detailed studies of Starship’s potential for a Pluto mission haven’t been published yet. A Starship-launched Pluto probe would have its own unique challenges, and it’s unclear whether it would have any advantages over nuclear electric propulsion.

How much would all of this cost? It’s anyone’s guess at this point. Scientists estimated the Persephone concept would cost $3 billion, excluding launch costs, which might cost $1 billion or more if a Pluto mission requires a bespoke launch solution. Development of a nuclear electric propulsion system would almost certainly cost billions of dollars, too.

All of this suggests 50 years or more might elapse between the first and second explorations of Pluto. That is in line with the span of time between the first flybys of Uranus and Neptune by NASA’s Voyager spacecraft in 1986 and 1989, and the earliest possible timeline for a mission to revisit those two ice giants.

So, it’s no surprise scientists are girding for a long wait—and perhaps taking a renewed interest in their own life expectancies—until they get a second look at one of the most seductive worlds in our Solar System.

Photo of Stephen Clark

Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

We saw the heart of Pluto 10 years ago—it’ll be a long wait to see the rest Read More »