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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The mystery of why life uses molecules with specific orientations has deepened with a NASA-funded discovery that RNA — a key molecule thought to have potentially held the instructions for life before DNA emerged — can favor making the building blocks of proteins in either the left-hand or the right-hand orientation. Resolving this mystery could provide clues to the origin of life. The findings appear in research recently published in Nature Communications.
Proteins are the workhorse molecules of life, used in everything from structures like hair to enzymes (catalysts that speed up or regulate chemical reactions). Just as the 26 letters of the alphabet are arranged in limitless combinations to make words, life uses 20 different amino acid building blocks in a huge variety of arrangements to make millions of different proteins. Some amino acid molecules can be built in two ways, such that mirror-image versions exist, like your hands, and life uses the left-handed variety of these amino acids. Although life based on right-handed amino acids would presumably work fine, the two mirror images are rarely mixed in biology, a characteristic of life called homochirality. It is a mystery to scientists why life chose the left-handed variety over the right-handed one.
A diagram of left-handed and right-handed versions of the amino acid isovaline, found in the Murchison meteorite.NASA DNA (deoxyribonucleic acid) is the molecule that holds the instructions for building and running a living organism. However, DNA is complex and specialized; it “subcontracts” the work of reading the instructions to RNA (ribonucleic acid) molecules and building proteins to ribosome molecules. DNA’s specialization and complexity lead scientists to think that something simpler should have preceded it billions of years ago during the early evolution of life. A leading candidate for this is RNA, which can both store genetic information and build proteins. The hypothesis that RNA may have preceded DNA is called the “RNA world” hypothesis.
If the RNA world proposition is correct, then perhaps something about RNA caused it to favor building left-handed proteins over right-handed ones. However, the new work did not support this idea, deepening the mystery of why life went with left-handed proteins.
The experiment tested RNA molecules that act like enzymes to build proteins, called ribozymes. “The experiment demonstrated that ribozymes can favor either left- or right-handed amino acids, indicating that RNA worlds, in general, would not necessarily have a strong bias for the form of amino acids we observe in biology now,” said Irene Chen, of the University of California, Los Angeles (UCLA) Samueli School of Engineering, corresponding author of the Nature Communications paper.
In the experiment, the researchers simulated what could have been early-Earth conditions of the RNA world. They incubated a solution containing ribozymes and amino acid precursors to see the relative percentages of the right-handed and left-handed amino acid, phenylalanine, that it would help produce. They tested 15 different ribozyme combinations and found that ribozymes can favor either left-handed or right-handed amino acids. This suggested that RNA did not initially have a predisposed chemical bias for one form of amino acids. This lack of preference challenges the notion that early life was predisposed to select left-handed-amino acids, which dominate in modern proteins.
“The findings suggest that life’s eventual homochirality might not be a result of chemical determinism but could have emerged through later evolutionary pressures,” said co-author Alberto Vázquez-Salazar, a UCLA postdoctoral scholar and member of Chen’s research group.
Earth’s prebiotic history lies beyond the oldest part of the fossil record, which has been erased by plate tectonics, the slow churning of Earth’s crust. During that time, the planet was likely bombarded by asteroids, which may have delivered some of life’s building blocks, such as amino acids. In parallel to chemical experiments, other origin-of-life researchers have been looking at molecular evidence from meteorites and asteroids.
“Understanding the chemical properties of life helps us know what to look for in our search for life across the solar system,” said co-author Jason Dworkin, senior scientist for astrobiology at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and director of Goddard’s Astrobiology Analytical Laboratory.
Dworkin is the project scientist on NASA’s OSIRIS-REx mission, which extracted samples from the asteroid Bennu and delivered them to Earth last year for further study.
“We are analyzing OSIRIS-REx samples for the chirality (handedness) of individual amino acids, and in the future, samples from Mars will also be tested in laboratories for evidence of life including ribozymes and proteins,” said Dworkin.
The research was supported by grants from NASA, the Simons Foundation Collaboration on the Origin of Life, and the National Science Foundation. Vázquez-Salazar acknowledges support through the NASA Postdoctoral Program, which is administered by Oak Ridge Associated Universities under contract with NASA.
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Last Updated Nov 21, 2024 EditorWilliam SteigerwaldContactNancy N. Jonesnancy.n.jones@nasa.govLocationGoddard Space Flight Center Related Terms
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By NASA
Pictured (clockwise) from bottom left are astronauts Charles O. Hobaugh, commander; Mike Foreman, Leland Melvin, Robert L. Satcher Jr. and Randy Bresnik, all mission specialists; along with Barry E. “Butch” Wilmore, pilot; and Nicole Stott, mission specialist.NASA The STS-129 crew members pose for a portrait following a joint news conference with the Expedition 21 crew members on Nov. 24, 2009. Astronauts Charles O. Hobaugh, Mike Foreman, Leland Melvin, Robert L. Satcher Jr., Randy Bresnik, Butch Wilmore, and Nicole Stott launched from NASA’s Kennedy Space Center in Florida on Nov. 16, 2009, aboard the space shuttle Atlantis. Traveling with them was nearly 30,000 pounds of replacement parts and equipment that would keep the orbital outpost supplied for several years to come.
The Atlantis crew performed three demanding but successful spacewalks – and enjoyed a surprise Thanksgiving dinner on the station, courtesy of the Expedition 21 crew.
Image credit: NASA
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
A prototype of a robot designed to explore subsurface oceans of icy moons is reflected in the water’s surface during a pool test at Caltech in September. Conducted by NASA’s Jet Propulsion Laboratory, the testing showed the feasibility of a mission concept for a swarm of mini swimming robots.NASA/JPL-Caltech In a competition swimming pool, engineers tested prototypes for a futuristic mission concept: a swarm of underwater robots that could look for signs of life on ocean worlds.
When NASA’s Europa Clipper reaches its destination in 2030, the spacecraft will prepare to aim an array of powerful science instruments toward Jupiter’s moon Europa during 49 flybys, looking for signs that the ocean beneath the moon’s icy crust could sustain life. While the spacecraft, which launched Oct. 14, carries the most advanced science hardware NASA has ever sent to the outer solar system, teams are already developing the next generation of robotic concepts that could potentially plunge into the watery depths of Europa and other ocean worlds, taking the science even further.
This is where an ocean-exploration mission concept called SWIM comes in. Short for Sensing With Independent Micro-swimmers, the project envisions a swarm of dozens of self-propelled, cellphone-size swimming robots that, once delivered to a subsurface ocean by an ice-melting cryobot, would zoom off, looking for chemical and temperature signals that could indicate life.
Dive into underwater robotics testing with NASA’s futuristic SWIM (Sensing With Independent Micro-swimmers) concept for a swarm of miniature robots to explore subsurface oceans on icy worlds, and see a JPL team testing a prototype at a pool at Caltech in Pasadena, California, in September 2024. NASA/JPL-Caltech “People might ask, why is NASA developing an underwater robot for space exploration? It’s because there are places we want to go in the solar system to look for life, and we think life needs water. So we need robots that can explore those environments — autonomously, hundreds of millions of miles from home,” said Ethan Schaler, principal investigator for SWIM at NASA’s Jet Propulsion Laboratory in Southern California.
Under development at JPL, a series of prototypes for the SWIM concept recently braved the waters of a 25-yard (23-meter) competition swimming pool at Caltech in Pasadena for testing. The results were encouraging.
SWIM Practice
The SWIM team’s latest iteration is a 3D-printed plastic prototype that relies on low-cost, commercially made motors and electronics. Pushed along by two propellers, with four flaps for steering, the prototype demonstrated controlled maneuvering, the ability to stay on and correct its course, and a back-and-forth “lawnmower” exploration pattern. It managed all of this autonomously, without the team’s direct intervention. The robot even spelled out “J-P-L.”
Just in case the robot needed rescuing, it was attached to a fishing line, and an engineer toting a fishing rod trotted alongside the pool during each test. Nearby, a colleague reviewed the robot’s actions and sensor data on a laptop. The team completed more than 20 rounds of testing various prototypes at the pool and in a pair of tanks at JPL.
“It’s awesome to build a robot from scratch and see it successfully operate in a relevant environment,” Schaler said. “Underwater robots in general are very hard, and this is just the first in a series of designs we’d have to work through to prepare for a trip to an ocean world. But it’s proof that we can build these robots with the necessary capabilities and begin to understand what challenges they would face on a subsurface mission.”
Swarm Science
A model of the final envisioned SWIM robot, right, sits beside a capsule holding an ocean-composition sensor. The sensor was tested on an Alaskan glacier in July 2023 through a JPL-led project called ORCAA (Ocean Worlds Reconnaissance and Characterization of Astrobiological Analogs). The wedge-shaped prototype used in most of the pool tests was about 16.5 inches (42 centimeters) long, weighing 5 pounds (2.3 kilograms). As conceived for spaceflight, the robots would have dimensions about three times smaller — tiny compared to existing remotely operated and autonomous underwater scientific vehicles. The palm-size swimmers would feature miniaturized, purpose-built parts and employ a novel wireless underwater acoustic communication system for transmitting data and triangulating their positions.
Digital versions of these little robots got their own test, not in a pool but in a computer simulation. In an environment with the same pressure and gravity they would likely encounter on Europa, a virtual swarm of 5-inch-long (12-centimeter-long) robots repeatedly went looking for potential signs of life. The computer simulations helped determine the limits of the robots’ abilities to collect science data in an unknown environment, and they led to the development of algorithms that would enable the swarm to explore more efficiently.
The simulations also helped the team better understand how to maximize science return while accounting for tradeoffs between battery life (up to two hours), the volume of water the swimmers could explore (about 3 million cubic feet, or 86,000 cubic meters), and the number of robots in a single swarm (a dozen, sent in four to five waves).
In addition, a team of collaborators at Georgia Tech in Atlanta fabricated and tested an ocean composition sensor that would enable each robot to simultaneously measure temperature, pressure, acidity or alkalinity, conductivity, and chemical makeup. Just a few millimeters square, the chip is the first to combine all those sensors in one tiny package.
Of course, such an advanced concept would require several more years of work, among other things, to be ready for a possible future flight mission to an icy moon. In the meantime, Schaler imagines SWIM robots potentially being further developed to do science work right here at home: supporting oceanographic research or taking critical measurements underneath polar ice.
More About SWIM
Caltech manages JPL for NASA. JPL’s SWIM project was supported by Phase I and II funding from NASA’s Innovative Advanced Concepts (NIAC) program under the agency’s Space Technology Mission Directorate. The program nurtures visionary ideas for space exploration and aerospace by funding early-stage studies to evaluate technologies that could transform future NASA missions. Researchers across U.S. government, industry, and academia can submit proposals.
How the SWIM concept was developed Learn about underwater robots for Antarctic climate science See NASA’s network of ready-to-roll mini-Moon rovers News Media Contact
Melissa Pamer
Jet Propulsion Laboratory, Pasadena, Calif.
626-314-4928
melissa.pamer@jpl.nasa.gov
2024-162
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Last Updated Nov 20, 2024 Related Terms
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By European Space Agency
Video: 00:04:30 Explore the immense power of water as ESA’s Mars Express takes us on a flight over curving channels, streamlined islands and muddled ‘chaotic terrain’ on Mars, soaking up rover landing sites along the way.
This beautiful flight around the Oxia Palus region of Mars covers a total area of approximately 890 000 km2, more than twice the size of Germany. Central to the tour is one of Mars’s largest outflow channels, Ares Vallis. It stretches for more than 1700 km2 and cascades down from the planet’s southern highlands to enter the lower-lying plains of Chryse Planitia.
Billions of years ago, water surged through Ares Vallis, neighbouring Tiu Vallis, and numerous other smaller channels, creating many of the features observed in this region today.
Enjoy the flight!
After enjoying a spectacular global view of Mars we focus in on the area marked by the white rectangle. Our flight starts over the landing site of NASA’s Pathfinder mission, whose Sojourner rover explored the floodplains of Ares Vallis for 12 weeks in 1997.
Continuing to the south, we pass over two large craters named Masursky and Sagan. The partially eroded crater rim of Masursky in particular suggests that water once flowed through it, from nearby Tiu Vallis.
The Masurky Crater is filled with jumbled blocks, and you can see many more as we turn north to Hydaspis Chaos. This ‘chaotic terrain’ is typical of regions influenced by massive outflow channels. Its distinctive muddled appearance is thought to arise when subsurface water is suddenly released from underground to the surface. The resulting loss of support from below causes the surface to slump and break into blocks of various sizes and shapes.
Just beyond this chaotic array of blocks is Galilaei crater, which has a highly eroded rim and a gorge carved between the crater and neighbouring channel. It is likely that the crater once contained a lake, which flooded out into the surroundings. Continuing on, we see streamlined islands and terraced river banks, the teardrop-shaped island ‘tails’ pointing in the downstream direction of the water flow at the time.
Crossing over Ares Vallis again, the flight brings us to the smoother terrain of Oxia Planum and the planned landing site for ESA’s ExoMars Rosalind Franklin rover. The primary goal of the mission is to search for signs of past or present life on Mars, and as such, this once water-flooded region is an ideal location.
Zooming out, the flight ends with a stunning bird’s-eye view of Ares Vallis and its fascinating water-enriched neighbourhood.
Disclaimer: This video is not representative of how Mars Express flies over the surface of Mars. See processing notes below.
How the movie was made
This film was created using the Mars Express High Resolution Stereo Camera Mars Chart (HMC30) data, an image mosaic made from single orbit observations of the High Resolution Stereo Camera (HRSC). The mosaic, centred at 12°N/330°E, is combined with topography information from the digital terrain model to generate a three-dimensional landscape.
For every second of the movie, 50 separate frames are rendered following a predefined camera path in the scene. A three-fold vertical exaggeration has been applied. Atmospheric effects such as clouds and haze have been added to conceal the limits of the terrain model. The haze starts building up at a distance of 300 km.
The HRSC camera on Mars Express is operated by the German Aerospace Center (DLR). The systematic processing of the camera data took place at the DLR Institute for Planetary Research in Berlin-Adlershof. The working group of Planetary Science and Remote Sensing at Freie Universität Berlin used the data to create the film.
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By NASA
Johnson Space Center Vibration Test FacilityNASA Nov. 14, 2024
NASA Johnson Invites Proposals to Lease Vibration Test Facility
NASA’s Johnson Space Center is seeking proposals for the use of its historic, but underused, Vibration and Acoustic Test Facility. Prospective tenants must submit facility walk-through requests by Monday, Nov. 18.
Final proposals are due by 12 p.m. EST Monday, Dec. 16, and must promote activities that will build, expand, modernize, or operate aerospace-related capabilities at NASA Johnson and help preserve the historic and iconic building through preservation and adaptive reuse.
NASA plans to sign a National Historic Preservation Act (NHPA) lease agreement for the facility, also known as Building 49, for a five-year base period and one five-year extension to be negotiated between NASA and the tenant. To request a walk-through, send an email to hq-realestate@mail.nasa.gov.
“This historic facility has been used for decades to ensure the success and safety of all human spaceflight missions by putting engineering designs and hardware to the ultimate stress tests,” said NASA Johnson Director Vanessa Wyche. “For more than 60 years, NASA Johnson has been the hub of human space exploration and this agreement will be a vital part of the center’s efforts to develop a robust and durable space economy that refines our understanding of the solar system and space exploration.”
All proposals must adhere to the guidelines detailed in the Agency Announcement for Proposals describing concept plans for development of the property, including any modifications proposed to the building; a statement of financial capability to successfully achieve and sustain operations, demonstrated experience with aerospace-related services or other space-related activities, and a detailed approach to propelling the space economy.
The nine-story building complex has a gross square footage of 62,737 square feet and consists of a north wing measuring 62 feet long, 268 feet wide and 106 feet tall, and a central wing about 64 feet long and 115 feet wide. Building 49 currently houses five laboratories, including the General Vibration Laboratory, Modal Operations Laboratory, Sonic Fatigue Laboratory, Spacecraft Acoustic Laboratory, and Spacecraft Vibration Laboratory. The south administrative portion of the building is not included in the property offered for lease.
As the home of Mission Control Center for the agency’s human space missions, astronaut training, robotics, human health and space medicine, NASA Johnson leads the way for the human exploration. Leveraging its unique role and location, the center is developing multiple lease agreements, including the recently announced Exploration Park, to sustain its key role in helping the human spaceflight community foster a robust space.
In the coming years, NASA and its academic, commercial, and international partners will see the completion of the International Space Station Program, the commercial development of low Earth orbit, and the first human Artemis campaign missions establishing sustainable human presence on the Moon in preparation for human missions to Mars.
Johnson already is leading the commercialization of space with the commercial cargo and crew programs and private astronaut missions to the space station. The center also is supporting the development of commercial space stations in low Earth orbit, and lunar-capable commercial spacesuits and lunar landers that will be provided as services to both NASA and the private sector to accelerate human access to space. Through the development of Exploration Park, the center will broaden the scope of the human spaceflight community that is tackling the many difficult challenges ahead.
Learn more about NASA Johnson’s efforts to collaborate with industry partners:
https://www.nasa.gov/johnson/frontdoor
-end-
Kelly Humphries
Johnson Space Center, Houston
281-483-5111
kelly.o.humphries@nasa.gov
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