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By Space Force
Over the past two years, the first U.S. space service component has tripled in size, established a 24/7 space watch cell and executed three Tier 1 Combatant Command exercises.
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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
Astrobiology Explore More
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By NASA
Early conceptual renderings of cargo variants of human lunar landing systems from NASA’s providers SpaceX, left, and Blue Origin, right. The large cargo landers will have the capability to land approximately 26,000 to 33,000 pounds (12-15 metric tons) of large, heavy payload on the lunar surface. Credit: SpaceX/Blue Origin NASA, along with its industry and international partners, is preparing for sustained exploration of the lunar surface with the Artemis campaign to advance science and discovery for the benefit of all. As part of that effort, NASA intends to award Blue Origin and SpaceX additional work under their existing contracts to develop landers that will deliver large pieces of equipment and infrastructure to the lunar surface.
NASA expects to assign demonstration missions to current human landing system providers, SpaceX and Blue Origin, to mature designs of their large cargo landers following successful design certification reviews. The assignment of these missions builds on the 2023 request by NASA for the two companies to develop cargo versions of their crewed human landing systems, now in development for Artemis III, Artemis IV, and Artemis V.
“NASA is planning for both crewed missions and future services missions to the Moon beyond Artemis V,” said Stephen D. Creech, assistant deputy associate administrator for technical, Moon to Mars Program Office. “The Artemis campaign is a collaborative effort with international and industry partners. Having two lunar lander providers with different approaches for crew and cargo landing capability provides mission flexibility while ensuring a regular cadence of Moon landings for continued discovery and scientific opportunity.”
NASA plans for at least two delivery missions with large cargo. The agency intends for SpaceX’s Starship cargo lander to deliver a pressurized rover, currently in development by JAXA (Japan Aerospace Exploration Agency), to the lunar surface no earlier than fiscal year 2032 in support of Artemis VII and later missions. The agency expects Blue Origin to deliver a lunar surface habitat no earlier than fiscal year 2033.
“Based on current design and development progress for both crew and cargo landers and the Artemis mission schedules for the crew lander versions, NASA assigned a pressurized rover mission for SpaceX and a lunar habitat delivery for Blue Origin,” said Lisa Watson-Morgan, program manager, Human Landing System, at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “These large cargo lander demonstration missions aim to optimize our NASA and industry technical expertise, resources, and funding as we prepare for the future of deep space exploration.”
SpaceX will continue cargo lander development and prepare for the Starship cargo mission under Option B of the NextSTEP Appendix H contract. Blue Origin will conduct its cargo lander work and demonstration mission under NextSTEP Appendix P. NASA expects to issue an initial request for proposals to both companies in early 2025.
With the Artemis campaign, NASA will explore more of the Moon than ever before, learn how to live and work away from home, and prepare for future exploration of Mars. NASA’s SLS (Space Launch System) rocket, exploration ground systems, and Orion spacecraft, along with commercial human landing systems, next-generation spacesuits, Gateway lunar space station, and future rovers are NASA’s foundation for deep space exploration.
For more on NASA’s Human Landing System Program, visit:
https://www.nasa.gov/hls
-end-
James Gannon
Headquarters, Washington
202-358-1600
james.h.gannon@nasa.gov
Corinne Beckinger
Marshall Space Flight Center, Huntsville, Ala.
256-544-0034
corinne.m.beckinger@nasa.gov
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Last Updated Nov 19, 2024 EditorJessica TaveauLocationNASA Headquarters Related Terms
Human Landing System Program Artemis Exploration Systems Development Mission Directorate Marshall Space Flight Center View the full article
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By NASA
NASA/Joel Kowsky In this photo, NASA’s SLS (Space Launch System) rocket, carrying the Orion spacecraft, lifts off the pad at Launch Complex 39B at the agency’s Kennedy Space Center in Florida at 1:47 a.m. EST on Nov. 16, 2022. Set on a path to the Moon, this officially began the Artemis I mission.
Since the completion of Orion’s 25.5-day mission around the Moon and back, teams across NASA have been hard at work preparing for the upcoming Artemis II test flight, which will send four astronauts on a 10-day mission around the Moon, paving the way for humans to land on the Moon as part of the Artemis III mission.
Under NASA’s Artemis campaign, the agency will establish the foundation for long-term scientific exploration at the Moon, land the first woman, first person of color, and its first international partner astronaut on the lunar surface, and prepare for human expeditions to Mars for the benefit of all.
Image Credit: NASA/Joel Kowsky
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By USH
While observing the Orion Nebula with his 12-inch Dobsonian telescope, a sky-watcher noticed an unusual flashing object. As stars appeared to drift due to Earth's rotation, this particular object while flashing approximately every 20 seconds clearly travels through deep space.
The observer wonders whether it might be a rotating satellite or not. However, this isn’t the first sighting of cigar-shaped UFOs or other mysterious objects traveling through space near the Orion Nebula, so it is quite possible that it could be an interstellar craft.
Over the years, I have shared several articles, complete with images and videos, documenting similar UFO sightings around the Orion Nebula. You can explore these under the tag: Orion Nebula.
Interestingly, these sightings have all occurred between November and February, suggesting there may be a seasonal pattern to these observations.
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