TYB
NASA Astronomy Picture of the Day
November 27, 2024
The Meteor and the Comet
How different are these two streaks? The streak on the upper right is Comet Tsuchinshan-Atlas showing an impressive dust tail. The comet is a large and dirty iceberg that entered the inner Solar System and is shedding gas and dust as it is warmed by the Sun's light. The streak on the lower left is a meteor showing an impressive evaporation trail. The meteor is a small and cold rock that entered the Earth's atmosphere and is shedding gas and dust as it is warmed by molecular collisions. The meteor was likely once part of a comet or asteroid – perhaps later composing part of its tail. The meteor was gone in a flash and was only caught by coincidence during a series of exposures documenting the comet's long tail. The featured image was captured just over a month ago from Sichuan Province in China.
https://apod.nasa.gov/apod/astropix.html
Post falsely claims discovery of dead bodies forced NASA to stop underwater exploration
November 27, 2024 at 06:12
Although better known for its work as a space agency, this has not stopped NASA from exploring Earth’s oceans.
But a social media account recently claimed in a thread that NASA discovered “thousands of people died at the very depth of the oceans” and halted all oceanography studies.
But the claim is false; NASA has not stopped its undersea exploration activities. The purported dead bodies shown in the thread are sculptures that form part of a large underwater art installation.
“3 reasons why NASA Stopped Exploring The Ocean. This will shock you,” reads an X post published as a part of a thread on November 14, 2024.
It claims the National Aeronautics and Space Administration, known worldwide as NASA, ended ocean exploration when they found thousands of people dįed “at the very depth of the oceans (sic)”.
The thread, retweeted more than 4,600 times, comprises five posts. The first has two photos, while the second features a minute-long video.
The photos show what looks like two men – one standing, the other prostrate – with a sea plant in the background.
The video, meanwhile, pans to an underwater environment, revealing more of the humanlike figures.
The claim is emphasised in the third and fourth posts while the last post offers discounted gadgets from the global smart-accessory brand Oraimo.
Founded in July 1958, NASA “leads studying Earth science, including climate, our Sun, solar system, and the larger universe” (archived here).
While its main focus is aeronautics and space exploration, it also collects and analyses “long-term ocean data from satellites”.
However, the claim that the agency stopped studying the oceans because it discovered corpses underwater is false.
Underwater art
AFP Fact Check traced the source of the photos and video to a TikTok account called “exploracao.subaquatica” whose name appears in the X post.
The TikTok account published the video on October 28, 2024, with the hashtags “#underwater #scubadivng #ocean #scary” as the caption, adding the actions in the footage “are performed or supervised by professionals”.
AFP then took screenshots from the video and conducted a reverse image search.
We found a similar video published on Shutterstock, a photo and video-sharing website, on December 10, 2021 (archived here).
Several similar clips showing the same scene were also published on the platform.
The caption explains that the footage showed the “Museum of Underwater Sculpture Ayia Napa” created by sculptor Jason deCaires Taylor.
The site is located at Pernera Beach in Ayia Napa, Cyprus (archived here).
A visual analysis of the Shutterstock clips and the one in the video shows the same features.
For instance, the sculpture seen at the beginning of the clip in the claim is also present in the Shutterstock clip, along with the distinctive spiky tree.
Another Shutterstock clip shows an assembly of sculptures, matching another part of the clip in the false claim.
A keyword search for “Jason deCaires Taylor” leads to his Instagram account, which includes a link to his website and another named “underwatersculptor.com” (archived here).
AFP Fact Check has debunked other false claims attributed to the artist’s work (here and here).
NASA ocean exploration
BBC reported in January 2022 that NASA was exploring the “deepest part of the ocean” called the Hadal Zone to “explore and probe the limits of life on Earth,” in partnership with Massachusetts-based Woods Hole Oceanographic Institution (WHOI) (archived here).
“The Hadal Zone is the deepest part of the ocean—from 20,000 to 36,000 feet. It is also the least explored place on Earth,” reads a message on the website dedicated to the exploration (archived here).
In addition to its oceanography work, NASA launched its Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite in February 2024.
According to a press release on its website, the US agency said “PACE will study microscopic life in the oceans and microscopic particles in the atmosphere”.
https://factcheck.afp.com/doc.afp.com.36NB3ET
https://www.tiktok.com/@exploracao.subaquatica
Discovery Alert: a ‘Hot Neptune’ in a Tight Orbit
Nov 26, 2024
The Discovery
A Neptune-sized planet, TOI-3261 b, makes a scorchingly close orbit around its host star.
Only the fourth object of its kind ever found, the planet could reveal clues as to how planets such as these form.
Key Facts
An international team of scientists used the NASA space telescope, TESS (the Transiting Exoplanet Survey Satellite), to discover the exoplanet (a planet outside our solar system), then made further observations with ground-based telescopes in Australia, Chile, and South Africa.
The measurements placed the new planet squarely in the “hot Neptune desert” – a category of planets with so few members that their scarcity evokes a deserted landscape.
This variety of exoplanet is similar to our own Neptune in size and composition, but orbits extremely closely to its star. In this case, a “year” on TOI-3261 b is only 21 hours long.
Such a tight orbit earns this planet its place in an exclusive group with, so far, only three other members: ultra-short-period hot Neptunes whose masses have been precisely measured.
Details
Planet TOI-3261 b proves to be an ideal candidate to test new computer models of planet formation. Part of the reason hot Neptunes are so rare is that it is difficult to retain a thick gaseous atmosphere so close to a star.
Stars are massive, and so exert a large gravitational force on the things around them, which can strip the layers of gas surrounding a nearby planet. They also emit huge amounts of energy, which blow the gas layers away.
Both of these factors mean that hot Neptunes such as TOI-3261 b might have started out as much larger, Jupiter-sized planets, and have since lost a large portion of their mass.
By modeling different starting points and development scenarios, the science team determined that the star and planet system is about 6.5 billion years old, and that the planet started out as a much larger gas giant.
It likely lost mass, however, in two ways: photoevaporation, when energy from the star causes gas particles to dissipate, and tidal stripping, when the gravitational force from the star strips layers of gas from the planet.
The planet also might have formed farther away from its star, where both of these effects would be less intense, allowing it to retain its atmosphere.
The remaining atmosphere of the planet, one of its most interesting features, will likely invite further atmospheric analysis, perhaps helping to unravel the formation history of this denizen of the “hot Neptune desert.”
Planet TOI-3261 b is about twice as dense as Neptune, indicating that the lighter parts of its atmosphere have been stripped away over time, leaving only the heavier components.
This shows that the planet must have started out with a variety of different elements in its atmosphere, but at this stage, it is hard to tell exactly what.
This mystery could be solved by observing the planet in infrared light, perhaps using NASA’s James Webb Space Telescope – an ideal way to see the identifying fingerprints of the different molecules in the planet’s atmosphere.
This will not just help astronomers understand the past of TOI-3261 b, but also begin to uncover the physical processes behind all hot, giant planets.
Fun Facts
The first-ever discovery of an ultra-short-period hot Neptune, LTT-9779 b, came in 2020. Since then, TESS discoveries TOI-849 b and TOI-332 b have also joined the elite ultra-short-period hot-Neptune club (with masses that have been precisely measured).
Both LTT-9779 b and TOI-849 b are in the queue for infrared observations with the James Webb Space Telescope, potentially broadening our understanding of these planets’ atmospheres in the coming years.
https://science.nasa.gov/universe/exoplanets/discovery-alert-a-hot-neptune-in-a-tight-orbit/
https://iopscience.iop.org/article/10.3847/1538-3881/ad60be/pdf
NASA Data Reveals Role of Green Spaces in Cooling Cities
Nov 26, 2024
As any urban dweller who has lived through a heat wave knows, a shady tree can make all the difference. But what happens when there’s no shade available?
A recent study in Nature Communications used NASA satellite data to identify a major gap in global resilience to climate change: cities in the Global South have far less green space — and therefore less cooling capacity — than cities in the Global North.
The terms Global North and Global South were used in the study to distinguish developed countries (mostly in the Northern Hemisphere) from developing nations (mostly in the Southern Hemisphere).
Cities tend to be hotter than nearby rural areas because of the urban heat island effect. Heat-trapping dark surfaces such as sidewalks, buildings, and roads absorb heat from the Sun’s rays, which raises the temperature of the city.
Extreme heat poses serious health threats for urban residents, including dehydration, heat stroke, and even death. Though not a cure-all, greenery provides shade and releases moisture into the air, cooling the surroundings.
“Cities can strategically prioritize developing new green spaces in areas that have less green space,” said Christian Braneon, a climate scientist at NASA’s Goddard Institute for Space Studies in New York who was not affiliated with this study.
“Satellite data can be really helpful for this.”
An international team of researchers led by Yuxiang Li, a doctoral student at Nanjing University, analyzed the 500 largest cities in the world to compare their cooling capacities.
They used data from the Landsat 8 satellite, jointly managed by NASA and the U.S. Geological Survey, to determine how effective green space was at cooling each city.
First, they calculated the average land surface temperature for the hottest month of 2018 for each city, as well as the average of the hottest months from 2017 to 2019.
Next, the researchers used a metric called the Normalized Difference Vegetation Index (NDVI) to map how much green space each city had.
The NDVI relies on the fact that healthy vegetation absorbs red light and reflects infrared light: the ratio of these wavelengths can show the density of healthy vegetation in a given satellite image.
Researchers found that cities in the Global South have just 70% of the greenery-related cooling capacity of cities in the Global North.
The green spaces in an average Global South city cool the temperature by about 4.5 F (2.5 C). In an average Global North city, that cooling capacity is 6.5 F (3.6 C).
This compounds an existing problem: cities in the South tend to be at lower latitudes (that is, nearer to the Equator), which are predicted to see more heat extremes in the coming years.
“It’s already clear that Global South countries will be impacted by heat waves, rising temperatures, and climatic extremes more than their Global North counterparts,” said Chi Xu, a professor of ecology at Nanjing University and a co-author of the study.
The Global South has less capacity to adapt to heat because air conditioning is less common and power outages are more frequent.
Why do cities in the Global South struggle to stay cool? Cities in the Global South tend to have less green space than cities in the Global North.
This mirrors studies of the disparities within cities, sometimes referred to as the “luxury effect”: wealthier neighborhoods tend to have more green space than poorer neighborhoods.
"Wealthier cities also have more urban green spaces than the poorest cities,” Chi said.
It’s unlikely that urban planners can close the gap between the study’s worst-performing city (Mogadishu, Somalia) and the best-performing one (Charlotte, North Carolina).
Mogadishu is a dense city with a dry climate that limits vegetation growth. Still, there’s a lot that each city can learn from its neighbors.
Within a given region, the researchers identified the city with the greatest cooling capacity and used that as a goal.
They calculated the difference between the best-performing city in the region and every city nearby to get the potential additional cooling capacity.
They found that cities’ average cooling capacity could be increased substantially — to as much as 18 F (10 C) — by systematically increasing green space quantity and quality.
“How you utilize green space is really going to vary depending on the climate and the urban environment you’re focused on,” said Braneon, whose research at NASA focuses on climate change and urban planning.
https://science.nasa.gov/earth/climate-change/nasa-data-reveals-role-of-green-spaces-in-cooling-cities/
https://www.nature.com/articles/s41467-024-51355-0
Bio Tech Dominates Research Schedule to Advance Space, Earth Industries
November 26, 2024
The Expedition 72 crew studied micro-algae and DNA-like nanomaterials on Tuesday to improve health in space and on Earth.
The orbital residents also worked on cargo transfers and lab maintenance aboard the International Space Station.
NASA Flight Engineer Nick Hague began his day processing radiation-resistant samples of Arthrospira C micro-algae and stowing them in an incubator for analysis.
The samples will be exposed to different light intensities to observe how they affect the micro-algae’s cell growth and oxygen production. Results may advance the development of spacecraft life support systems and fresh food production in space.
Afterward, Hague joined Commander Suni Williams of NASA for a different research session mixing water with samples of messenger RNA, or mRNA, and protein to create DNA-like nanomaterial products inside the Kibo laboratory module’s Life Science Glovebox.
Flight Engineer Butch Wilmore then transferred the samples, exposed them to ultrasonic waves, and imaged them with a spectrophotometer to measure the intensity of light at different wavelengths and evaluate the quality of the nanomaterials.
The samples will also be returned to Earth for further evaluation. Results may lead to improved therapies for Earth and space health conditions as well as advance the space economy.
Wilmore joined NASA Flight Engineer Don Pettit and removed external research hardware from inside Kibo’s airlock. The hardware housed a variety of samples exposed to the vacuum of space such as polymers, photovoltaic devices, and more.
The samples will be returned to Earth and examined to understand how space radiation, the extreme thermal environment, micrometeoroids, and more affect materials possibly benefitting the space industry.
Afterward, Pettit pedaled on an exercise cycle wearing breathing gear that measured his aerobic output in microgravity.
He wrapped up his shift packing gear for return to Earth inside the SpaceX Dragon cargo spacecraft due to undock from the Harmony module’s forward port on Thursday, Dec. 5.
Roscosmos Flight Engineers Alexey Ovchinin and Ivan Vagner worked inside the Progress 89 resupply spacecraft on Tuesday that has been docked to the Zvezda service module’s rear port since Aug. 17.
The duo first serviced the spacecraft’s docking mechanism then unpacked cargo for stowing inside the Nauka science module.
Cosmonaut Aleksandr Gorbunov had a light duty day primarily focusing on exercise inside the Tranquility module, jogging on the treadmill and working out on the advanced resistive exercise device.
https://blogs.nasa.gov/spacestation/2024/11/26/bio-tech-dominates-research-schedule-to-advance-space-earth-industries/
NASA’s Europa Clipper: Millions of Miles Down, Instruments Deploying
Nov 25, 2024
NASA’s Europa Clipper, which launched Oct. 14 on a journey to Jupiter’s moon Europa, is already 13 million miles (20 million kilometers) from Earth.
Two science instruments have deployed hardware that will remain at attention, extending out from the spacecraft, for the next decade — through the cruise to Jupiter and the entire prime mission.
A SpaceX Falcon Heavy rocket launched it away from Earth’s gravity, and now the spacecraft is zooming along at 22 miles per second (35 kilometers per second) relative to the Sun.
Europa Clipper is the largest spacecraft NASA has ever developed for a planetary mission.
It will travel 1.8 billion miles (2.9 billion kilometers) to arrive at Jupiter in 2030 and in 2031 will begin a series of 49 flybys, using a suite of instruments to gather data that will tell scientists if the icy moon and its internal ocean have the conditions needed to harbor life.
For now, the information mission teams are receiving from the spacecraft is strictly engineering data (the science will come later), telling them how the hardware is operating.
Things are looking good. The team has a checklist of actions the spacecraft needs to take as it travels deeper into space. Here’s a peek:
Boom Times
Shortly after launch, the spacecraft deployed its massive solar arrays, which extend the length of a basketball court.
Next on the list was the magnetometer’s boom, which uncoiled from a canister mounted on the spacecraft body, extending a full 28 feet (8.5 meters).
To confirm that all went well with the boom deployment, the team relied on data from the magnetometer’s three sensors.
Once the spacecraft is at Jupiter, these sensors will measure the magnetic field around Europa, both confirming the presence of the ocean thought to be under the moon’s icy crust and telling scientists about its depth and salinity.
On the Radar
After the magnetometer, the spacecraft deployed several antennas for the radar instrument. Now extending crosswise from the solar arrays, the four high-frequency antennas form what look like two long poles, each measuring 57.7 feet (17.6 meters) long.
Eight rectangular very-high-frequency antennas, each 9 feet (2.76 meters) long, were also deployed — two on the two solar arrays.
“It’s an exciting time on the spacecraft, getting these key deployments done,” said Europa Clipper project manager Jordan Evans of NASA’s Jet Propulsion Laboratory in Southern California.
“Most of what the team is focusing on now is understanding the small, interesting things in the data that help them understand the behavior of the spacecraft on a deeper level. That’s really good to see.”
Instrument Checkout
The remaining seven instruments will be powered on and off through December and January so that engineers can check their health.
Several instruments, including the visible imager and the gas and dust mass spectrometers, will keep their protective covers closed for the next three or so years to guard against potential damage from the Sun during Europa Clipper’s time in the inner solar system.
Mars-Bound
Once all the instruments and engineering subsystems have been checked out, mission teams will shift their focus to Mars.
On March 1, 2025, Europa Clipper will reach Mars’ orbit and begin to loop around the Red Planet, using the planet’s gravity to gain speed. (This effect is similar to how a ball thrown at a moving train will bounce off the train in another direction at a higher speed.)
Mission navigators already have completed one trajectory correction maneuver, as planned, to get the spacecraft on the precise course.
At Mars, scientists plan to turn on the spacecraft’s thermal imager to capture multicolored images of Mars as a test operation. They also plan to collect data with the radar instrument so engineers can be sure it’s operating as expected.
The spacecraft will perform another gravity assist in December 2026, swooping by Earth before making the remainder of the long journey to the Jupiter system. At that time, the magnetometer will measure Earth’s magnetic field, calibrating the instrument.
https://www.nasa.gov/missions/europa-clipper/nasas-europa-clipper-millions-of-miles-down-instruments-deploying/
Irradiated Turkey and Freeze-Dried Potatoes: How ISS Astronauts Celebrate Thanksgiving
Updated Nov 27, 2024 9:34 AM EST
Living and working 250 miles above the Earth, International Space Station (ISS) astronauts do not have the luxury of spending Thanksgiving with their families. But on the ISS, crewmembers are family.
Space station crews have celebrated Thanksgiving from orbit every November since 2000. Last year, for example, the Expedition 70 crew chowed down on turkey, duck, quail, seafood, and cranberry sauce—with chocolate, mochi, and even pumpkin spice cappuccinos for dessert.
Skylab 4 crewmembers Gerald P. Carr, Edward G. Gibson, and William R. Pogue were the first to celebrate Turkey Day in space—but there was no turkey.
The astronauts did, however, eat two meals for dinner after wrapping up a six-and-a-half-hour spacewalk.
As the menu has grown, so too has the number of astronauts partaking in the festivities.
In 1996, eight NASA astronauts and Roscosmos cosmonauts across two spacecraft set a record for the largest Thanksgiving gathering in orbit.
It didn’t hold for long—nine astronauts celebrated the following year representing four nations, also a record at that time.
In 2000, Expedition 1 astronauts set the precedent for annual ISS celebrations. Thanksgiving 2009 was the largest, with the crew of NASA’s Expedition 21 hosting STS-129 astronauts for a feast.
The 12 crewmembers, representing the U.S., Russia, Canada, and Belgium, ate two days early because the STS-129 crew departed on Thanksgiving Day.
This year, seven people will be aboard the ISS for Turkey Day. Among them are Boeing Starliner crew flight test (CFT) astronaut Butch Wilmore, who celebrated from the orbital laboratory in 2014, and Soyuz MS-26 crewmember Don Pettit, who did so in 2008.
Joining them are Wilmore’s crewmate Suni Williams, Pettit’s crewmates Alexey Ovchinin and Ivan Vagner, and SpaceX Crew-9 astronauts Nick Hague and Aleksandr Gorbunov.
Also in orbit will be taikonauts Cai Xuzhe, Song Lingdong, and Wang Haoze, the crew of China's Shenzhou 19 mission to the Tiangong space station.
https://www.flyingmag.com/modern/irradiated-turkey-and-freeze-dried-potatoes-how-iss-astronauts-celebrate-thanksgiving/
International Space Station dodges 2nd piece of space junk in 6 days
November 26, 2024
The International Space Station just dodged a piece of debris for the second time in less than a week.
Russia's robotic Progress 89 freighter, which has been docked to the ISS since August, fired its thrusters for about 3.5 minutes on Monday morning (Nov. 25) to get the station clear of a hunk of space junk.
"The debris avoidance maneuver positioned the orbital outpost farther away from a satellite fragment nearing the station’s flight path," NASA officials wrote in an update on Monday.
The burn began at 4:49 a.m. EST (0949 GMT) and raised the station's orbit by about 1,650 feet (500 meters), according to the Russian state-owned news agency TASS, which cited a statement from the nation's space agency Roscosmos.
Progress 89 performed a similar burn on Nov. 19. That one lasted about 5.5 minutes and ensured that the ISS steered clear of a fragment from a "defunct defense meteorological satellite" that broke apart in 2015, NASA officials said.
Low Earth orbit, where the space station flies, is getting more and more crowded these days.
According to the European Space Agency (ESA), about 10,200 active satellites circle the planet at the moment.
Most of them belong to SpaceX's Starlink broadband megaconstellation, which currently consists of about 6,700 operational craft.
The debris population is far larger still. ESA estimates that Earth orbit harbors about 40,500 objects at least 4 inches (10 centimeters) wide, 1.1 million pieces between 0.4 inches and 4 inches (1 to 10 cm) in diameter and 130 million that are at least 1 millimeter wide.
Even these tiny shards can be dangerous to satellites or crewed craft like the ISS, given the tremendous speeds at which they travel. For example, at the station's average altitude of 250 miles (400 kilometers), orbital velocity is about 17,500 mph (28,160 kph).
Dodging debris isn't a rare occurrence, as the events of the past week show. Indeed, a December 2022 NASA report found that the ISS had performed evasive burns 32 times since 1999.
https://www.space.com/space-exploration/international-space-station/international-space-station-dodges-2nd-piece-of-space-junk-in-6-days
Blue Origin forced to yank video of astronaut’s reaction to space over hateful, sexist comments
Nov. 26, 2024, 12:35 p.m. ET
Blue Origin was forced to yank down a clip of astronaut Emily Calandrelli’s candid reaction to being in space after the post was attacked by misogynistic internet trolls.
Calandrelli, 37 — a TV science program host and aerospace engineer who became the 100th woman in space Friday aboard one of the company’s ships — said she was brought to tears by critics of the short video, which showed her floating upside down in zero gravity as she stared out at Earth from a window.
“That’s our planet. Oh my God, this is space,” Calandrelli reflected, full of emotion, in the clip.
Almost immediately, thousands of hateful Netizens posted offensive comments targeting her, including even about her looks, according to the Daily Mail.
“It’s not an achievement being a woman,” a user wrote about the standout MIT grad.
Another man posted, “Would you consider yourself the hottest woman to ever go to space? Any other contenders?”
One person added, “why she moaning I cannot unhear it.”
The responses were so hurtful that Calandrelli, instead of basking in her historic feat aboard billionaire Jeff Bezos’ Origin spacecraft, said in on Instagram on Monday that she was in tears flying home after the mission.
“This all happened as I was flying home after experiencing the most perfect, wonderful dream-achieving experience of my life,” she wrote.
“And instead of being on cloud nine, I’m crying in my seat staring out the window. Because of course this happened. Of course I should have expected this.”
She said she texted other female astronauts, her “space sisters,” for advice, and they comforted her and told her she has “nothing to be embarrassed of.
“I had to take a moment to feminism myself if I’m being quite honest,” she said.
“But I refuse to give much time to the small men on the internet. I feel experiences in my soul. It’s a trait I got from my father.
We feel every emotion deeply and what a beautiful way that is to experience life. This joy is tattooed on my heart.
“I will not apologize or feel weird about my reaction. It’s wholly mine and I love it.”
Calandrelli added that when she left the airplane she took home after her mission, she was recognized by a female flight attendant who saw that she had been crying.
” ‘Don’t let them dull your shine,’ ” the flight attendant told Calandrelli, according to the astronaut in the post.
“I felt an immediate sense of camaraderie with her, with all women,” Calandrelli said.
Calandrelli, who is better known online as “Space Gal,” is a New York Times bestselling author and Emmy-nominated TV host who has amassed a major following talking about space and science.
She had been publicly documenting her preparations for the space flight, with the excited astronaut compiling a flash drive filled with a list of dreams from her followers, which she said she would to take to space with her, raising thousands of dollars for children’s charities in the process.
She and five other “space tourists” blasted off from Blue Origin’s Texas spaceport Friday for the ninth manned test of the company’s New Shepherd spacecraft.
The New Shepard capsule, RSS First Step, touched back down to Earth about 10 minutes after takeoff and two and a half minutes after the booster had landed, according to Space News.
The capsule reached a peak altitude of 66 kilometers (41 miles) above sea level, Blue Origin said.
“You’re seeing so many emotions intertwined,” Calandrelli wrote of her experience. “Excitement, awe, and pride — but to be honest a little fear and confusion too.
You just launched on a rocket and you’re seeing something you’ve never seen before (all while weightless and upside down).
“It’s scary, exhilarating, confusing, and completely and utterly joyful. So incredibly joyful.”
Blue Origin did not respond to a Post request for comment Tuesday.
https://nypost.com/2024/11/26/world-news/blue-origin-forced-to-yank-video-of-astronaut-emily-calandrellis-reaction-to-space-over-hateful-sexist-comments/
NASA awards SpaceX a contract for one of the few things it hasn’t done yet
Nov 26, 2024 10:23 AM
When you compare SpaceX to the world's other space enterprises, it's probably easier to list the things SpaceX hasn't done instead of reciting all of the company's achievements.
One of these is the launch of nuclear materials. SpaceX has launched a handful of planetary science missions for NASA, but these spacecraft have all used solar arrays to generate electricity.
In this century, NASA's probes relying on nuclear power have all flown on rockets built by United Launch Alliance (ULA), a 50-50 joint venture between Boeing and Lockheed Martin.
This is about to change with a $256.6 million contract NASA awarded to SpaceX on Monday. The contract covers launch services and related costs for SpaceX to launch Dragonfly, a rotorcraft designed to explore the alien environment of Saturn's largest moon, Titan.
Dragonfly's power source is a radioisotope thermoelectric generator (RTG), which generates electricity from the heat put out by the radioactive decay of plutonium-238.
These plutonium-fueled generators have flown on many previous space missions, including NASA's Perseverance and Curiosity rovers on Mars, the New Horizons spacecraft that beamed back the first up-close views of Pluto, and the long-lived Voyager probes exploring interstellar space.
All of these missions were launched on rockets that have either retired or are nearing retirement: the Atlas V, the Titan, and the space shuttle, to name a few.
So, it is time for NASA to certify a new generation of rockets to launch nuclear-powered payloads.
The Space Force is already working on this for ULA's Vulcan rocket, the replacement for the Atlas V, which is due to launch an innovative nuclear propulsion demonstration as soon as 2027.
SpaceX's Falcon Heavy has launched 11 times, all successfully, and is based on the Falcon 9 rocket rated to ferry people into orbit.
NASA already certified Falcon Heavy to launch its most expensive robotic missions, such as the Europa Clipper mission, which launched last month.
But there is an additional certification required to launch nuclear materials, including a review of the rocket's explosive self-destruct range safety system to ensure it would not damage the payload and cause a release of radioactive plutonium.
The RTG itself is designed to survive an impact with the ocean intact.
Notably, the Dragonfly launch was one of the first times United Launch Alliance has been eligible to bid its new Vulcan rocket for a NASA launch contract.
NASA officials gave the green light for the Vulcan rocket to compete head-to-head with SpaceX's Falcon 9 and Falcon Heavy after ULA's new launcher had a successful debut launch earlier this year.
With this competition, SpaceX came out on top.
A half-life of 88 years
NASA's policy for new space missions is to use solar power whenever possible.
For example, Europa Clipper was originally supposed to use a nuclear power generator, but engineers devised a way for the spacecraft to use expansive solar panels to capture enough sunlight to produce electricity, even at Jupiter's vast distance from the Sun.
But there are some missions where this isn't feasible. One of these is Dragonfly, which will soar through the soupy nitrogen-methane atmosphere of Titan.
Saturn's largest moon is shrouded in cloud cover, and Titan is nearly 10 times farther from the Sun than Earth, so its surface is comparatively dim.
Dragonfly will launch with about 10.6 pounds (4.8 kilograms) of plutonium-238 to fuel its power generator. Plutonium-238 has a half-life of 88 years.
With no moving parts, RTGs have proven quite reliable, powering spacecraft for many decades. NASA's twin Voyager probes are approaching 50 years since launch.
The Dragonfly rotorcraft will launch cocooned inside a transit module and entry capsule, then descend under parachute through Titan's atmosphere, which is four times denser than Earth's.
Finally, Dragonfly will detach from its descent module and activate its eight rotors to reach a safe landing.
Once on Titan, Dragonfly is designed to hop from place to place on numerous flights, exploring environments rich in organic molecules, the building blocks of life.
This is one of NASA's most exciting, and daring, robotic missions of all time.
After launching from NASA's Kennedy Space Center in Florida in July 2028, it will take Dragonfly about six years to reach Titan.
When NASA selected the Dragonfly mission to begin development in 2019, the agency hoped to launch the mission in 2026.
NASA later directed Dragonfly managers to target a launch in 2027, and then 2028, requiring the mission to change from a medium-lift to a heavy-lift rocket.
https://arstechnica.com/space/2024/11/with-dragonfly-contract-nasa-will-certify-spacex-for-nuclear-powered-payloads/