NASA – Page 15

NASA scientist on 2023 temperatures: “We’re frankly astonished”

2023, Berkeley Earth, climate change, global warming, NASA, NOAA, Science / DJ Henderson / January 12, 2024

Extremely unusual —

NASA, NOAA, and Berkeley Earth have released their takes on 2023’s record heat.

John Timmer – Jan 12, 2024 6: 33 pm UTC

A global projection map with warm areas shown in read, and color ones in blue. There is almost no blue. — Enlarge / Warming in 2023 was widespread.

Earlier this week, the European Union’s Earth science team came out with its analysis of 2023’s global temperatures, finding it was the warmest year on record to date. In an era of global warming, that’s not especially surprising. What was unusual was how 2023 set its record—every month from June on coming in far above any equivalent month in the past—and the size of the gap between 2023 and any previous year on record.

The Copernicus dataset used for that analysis isn’t the only one of the sort, and on Friday, Berkeley Earth, NASA, and the National Oceanic and Atmospheric Administration all released equivalent reports. And all of them largely agree with the EU’s: 2023 was a record, and an unusual one at that. So unusual that NASA’s chief climate scientist, Gavin Schmidt, introduced his look at 2023 by saying, “We’re frankly astonished.”

Despite the overlaps with the earlier analysis, each of the three new ones adds some details that flesh out what made last year so unusual.

Each of the three analyses uses slightly different methods to do things like fill in areas of the globe where records are sparse, and uses a different baseline. Berkeley Earth was the only team to do a comparison with pre-industrial temperatures, using a baseline of the 1850–1900 temperatures. Its analysis suggests that this is the first year to finish over 1.5° C above preindustrial temperatures.

Most countries have committed to an attempt to keep temperatures from consistently coming in above that point. So, at one year, we’re far from consistently failing our goals. But there’s every reason to expect that we’re going to see several more years exceeding this point before the decade is out. And that clearly means we have a very short timeframe before we get carbon emissions to drop, or we’ll commit to facing a difficult struggle to get temperatures back under this threshold by the end of the century.

Berkeley Earth also noted that the warming was extremely widespread. It estimates that nearly a third of the Earth’s population lived in a region that set a local heat record. And 77 nations saw 2023 set a national record.

Enlarge / Lots of factors converged on warming in 2023.

The Berkeley team also had a nice graph laying out the influences of different factors on recent warming. Greenhouse gases are obviously the strongest and most consistent factor, but there are weaker short-term influences as well, such as the El Niño/La Niña oscillation and the solar cycle. Berkeley Earth and EU’s Copernicus also noted that an international agreement caused sulfur emissions from shipping to drop by about 85 percent in 2020, which would reduce the amount of sunlight scattered back out into space. Finally, like the EU team, they note the Hunga Tonga eruption.

An El Niño unlike any other

A shift from La Niño to El Niño conditions in the late spring is highlighted by everyone looking at this year, as El Niños tend to drive global temperatures upward. While it has the potential to develop into a strong El Niño in 2024, at the moment, it’s pretty mild. So why are we seeing record temperatures?

We’re not entirely sure. “The El Niño we’ve seen is not an exceptional one,” said NASA’s Schmidt. So, he reasoned, “Either this El Niño is different from all of them… or there are other factors going on.” But he was at a bit of a loss to identify the factors. He said that typically, there are a limited number of stories that you keep choosing from in order to explain a given year’s behavior. But, for 2023, none of them really fit.

Enlarge / Something very ominous happened to the North Atlantic last year.

Berkeley Earth had a great example of it in its graph of North Atlantic sea surface temperatures, which have been rising slowly for decades, until 2023 saw record temperatures with a freakishly large gap compared to anything previously on record. There’s nothing especially obvious to explain that.

Lurking in the background of all of this is climate scientist James Hansen’s argument that we’re about to enter a new regime of global warming, where temperatures increase at a much faster pace than they have until now. Most climate scientists don’t see compelling evidence for that yet. And, with El Niño conditions likely to prevail for much of 2024, we can expect a very hot year again, regardless of changing trends. So, it may take several more years to determine if 2023 was a one-off freak or a sign of new trends.

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A cat video highlighted a big year for lasers in space

lasers, NASA, psyche asteroid, Space / Mike M. / December 30, 2023

Pew Pew —

NASA has invested more than $700 million in testing laser communications in space.

Stephen Clark – Dec 30, 2023 11: 29 am UTC

Taters, the orange tabby cat of a Jet Propulsion Laboratory employee, stars in a video beamed from deep space by NASA's Psyche spacecraft. The graphics illustrate several features from the tech demo, such as Psyche’s orbital path, Palomar’s telescope dome, and technical information about the laser and its data bit rate. Tater’s heart rate, color, and breed are also on display. — Enlarge / Taters, the orange tabby cat of a Jet Propulsion Laboratory employee, stars in a video beamed from deep space by NASA’s Psyche spacecraft. The graphics illustrate several features from the tech demo, such as Psyche’s orbital path, Palomar’s telescope dome, and technical information about the laser and its data bit rate. Tater’s heart rate, color, and breed are also on display.

It’s been quite a year for laser communications in space. In October and November, NASA launched two pioneering demonstrations to test high-bandwidth optical communication links, and these tech demos are now showing some initial results.

On December 11, a laser communications terminal aboard NASA’s Psyche spacecraft on the way to an asteroid linked up with a receiver in Southern California. The near-infrared laser beam contained an encoded message in the form of a 15-second ultra-high-definition video showing a cat bouncing around a sofa, chasing the light of a store-bought laser toy.

Laser communications offer the benefit of transmitting data at a higher rate than achievable with conventional radio links. In fact, the Deep Space Optical Communications (DSOC) experiment on the Psyche spacecraft is testing technologies capable of sending data at rates 10 to 100 times greater than possible on prior missions.

“We’re looking to increase the amount of data we can get down to Earth, and that has a lot of advantages to us,” said Jeff Volosin, acting deputy associate administrator for NASA space communications and navigation program, before the launch of Psyche earlier this year.

Now, DSOC has set a record for the farthest distance a high-definition video has streamed from space. At the time, Psyche was traveling 19 million miles (31 kilometers) from Earth, about 80 times the distance between Earth and the Moon. Traveling at the speed of light, the video signal took 101 seconds to reach Earth, sent at the system’s maximum bit rate of 267 megabits per second, NASA said.

A playful experiment

After reaching the receiver at Palomar Observatory in San Diego County, each video frame was transmitted “live” to NASA’s Jet Propulsion Laboratory in Pasadena, California, where it was played in real time, according to NASA.

“One of the goals is to demonstrate the ability to transmit broadband video across millions of miles. Nothing on Psyche generates video data, so we usually send packets of randomly generated test data,” said Bill Klipstein, the tech demo’s project manager at JPL, in a statement. “But to make this significant event more memorable, we decided to work with designers at JPL to create a fun video, which captures the essence of the demo as part of the Psyche mission.”

The video of Taters, the orange tabby cat of a JPL employee, was recorded before the launch of Psyche and stored on the spacecraft for this demonstration. The robotic probe launched on October 13 aboard a SpaceX Falcon Heavy rocket, with the primary goal of flying to the asteroid Psyche, a metal-rich world in the asteroid belt between the orbits of Mars and Jupiter.

It will take six years for the Psyche probe to reach its destination, and NASA tacked on a laser communications experiment to help keep the spacecraft busy during the cruise. Since the launch in October, ground teams at JPL switched on the Deep Space Optical Communications (DSOC) experiment and ran it through some early tests.

One of the most significant technical challenges involved in the DSOC experiment was aligning the 8.6-inch (22-centimeter) optical telescope aboard Psyche with a transmitter and receiver fitted to ground-based telescopes in California and vice versa. Because Psyche is speeding through deep space, this problem is akin to trying to hit a dime from a mile away while the dime is moving, according to Abi Biswas, DSOC’s project technologist at JPL.

Once you achieve that feat, the signal that is received is still very weak and therefore requires very sensitive detectors and processing electronics which can take that signal and extract information that’s encoded in it,” Biswas said.

The telescope aboard Psyche is mounted on an isolation-and-pointing assembly to stabilize the optics and isolate them from spacecraft vibrations, according to NASA. This is necessary to eliminate jitters that could prevent a stable laser lock between Earth and the Psyche spacecraft.

“What optical or laser communications allows you is to achieve very high data rates, but on the downside, it’s a very narrow laser beam that requires very accurate pointing control,” Biswas told reporters before the launch. “For example, the platform disturbance from a typical spacecraft would throw off the pointing, so you need to actively isolate from it or control against it.

“For near-Earth missions, you can just control against it because you have enough control bandwidth,” he said. “From deep space, where the signals received are very weak, you don’t have that much control bandwidth, so you have to isolate from the disturbance.”

The Deep Space Optical Communications (DSOC) experiment is mounted on NASA's Psyche spacecraft on the way to an asteroid. The inset image shows the mirror of the instrument's telescope for receiving and transmitting laser signals. — Enlarge / The Deep Space Optical Communications (DSOC) experiment is mounted on NASA’s Psyche spacecraft on the way to an asteroid. The inset image shows the mirror of the instrument’s telescope for receiving and transmitting laser signals.

There’s another drawback of direct-to-Earth laser communications from space. Cloud cover over transmitting and receiving telescopes on Earth could block signals, so an operational optical communications network will require several ground nodes at different locations worldwide, ideally positioned in areas known for clear skies.

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Hubble back in service after gyro scare—NASA still studying reboost options

Hubble Space Telescope, NASA, Science, Space, spacex / Shannon Garcia / December 9, 2023

Enlarge / The Hubble Space Telescope viewed from Space Shuttle Atlantis during a servicing mission in 2009.

NASA

The Hubble Space Telescope resumed science observations on Friday after ground teams spent most of the last three weeks assessing the performance of a finicky gyroscope, NASA said.

The troublesome gyroscope is a critical part of the observatory’s pointing system. Hubble’s gyros measure how fast the spacecraft is turning, helping the telescope aim its aperture toward distant cosmic wonders.

Hubble still provides valuable scientific data for astronomers nearly 34 years since its launch aboard NASA’s Space Shuttle Discovery in 1990. Five more shuttle servicing missions repaired Hubble, upgraded its science instruments, and replaced hardware degraded from long-term use in space. Among other tasks, astronauts on the last of the shuttle repair flights in 2009 installed six new gyroscopes on Hubble.

Moving parts sometimes break

The gyros have long been one of the parts of Hubble that require the most upkeep. A wheel inside each gyro spins at a constant rate of 19,200 revolutions per minute, and the wheel is, in turn, sealed inside a cylinder suspended in a thick fluid, according to NASA. Electronics within each gyro detect very small movements of the axis of the wheel, which supply Hubble’s central computer with information about the spacecraft’s turn rate. Hair-thin wires route signals from the gyroscopes, and these wires can degrade over time.

Three of the six gyros installed on Hubble in 2009 have failed, and three others remain operational. The three still-functioning gyros are based on a newer design for longer life, but one of these units has shown signs of wear in the last few months. This gyroscope, designated Gyro 3, has always exhibited “consistent noisy behavior,” said Pat Crouse, Hubble project manager at NASA’s Goddard Space Flight Center.

Hubble typically needs three gyros to operate normally, so ground controllers shut down Gyro 3 for roughly seven years until Hubble needed it in 2018, when another gyroscope failed, leaving only three of the devices still working.

“Back in August, we saw issues,” Crouse told Ars this week. “It would sort of sporadically output some rate information that was not consistent with the observed spacecraft body rates, but it was short-lived, and we were characterizing what that performance was like and how much we could tolerate.”

The gyro’s performance worsened in November when it fed Hubble’s control system erroneous data. The gyroscope sensed that the spacecraft was changing its orientation when it really wasn’t moving. “That, then, contributed to an error in attitude that was kind of causing a little bit of drift,” Crouse said.

Automated software on Hubble detected the errors and put the spacecraft into “safe mode” two times last month. Hubble quickly resumed science observations each time but then went into safe mode again on November 23. Hubble managers took some extra time to gather data on the gyro’s health. Engineers commanded Hubble to move back and forth, and the suspect gyro consistently seemed to work well.

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