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Astronomers Using NASA's Hubble Discover Quasars Acting as Gravitational Lenses
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By NASA
ESA/Hubble & NASA, R. Windhorst, W. Keel This NASA/ESA Hubble Space Telescope image features a spiral galaxy, named UGC 10043. We don’t see the galaxy’s spiral arms because we are seeing it from the side. Located roughly 150 million light-years from Earth in the constellation Serpens, UGC 10043 is one of the somewhat rare spiral galaxies that we see edge-on.
This edge-on viewpoint makes the galaxy’s disk appear as a sharp line through space, with its prominent dust lanes forming thick bands of clouds that obscure our view of the galaxy’s glow. If we could fly above the galaxy, viewing it from the top down, we would see this dust scattered across UGC 10043, possibly outlining its spiral arms. Despite the dust’s obscuring nature, some active star-forming regions shine out from behind the dark clouds. We can also see that the galaxy’s center sports a glowing, almost egg-shaped ‘bulge’, rising far above and below the disk. All spiral galaxies have a bulge similar to this one as part of their structure. These bulges hold stars that orbit the galactic center on paths above and below the whirling disk; it’s a feature that isn’t normally obvious in pictures of galaxies. The unusually large size of this bulge compared to the galaxy’s disk is possibly due to UGC 10043 siphoning material from a nearby dwarf galaxy. This may also be why its disk appears warped, bending up at one end and down at the other.
Like most full-color Hubble images, this image is a composite, made up of several individual snapshots taken by Hubble at different times, each capturing different wavelengths of light. One notable aspect of this image is that the two sets of data that comprise this image were collected 23 years apart, in 2000 and 2023! Hubble’s longevity doesn’t just afford us the ability to produce new and better images of old targets; it also provides a long-term archive of data which only becomes more and more useful to astronomers.
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By NASA
This article is from the 2024 Technical Update
Autonomous flight termination systems (AFTS) are being progressively employed onboard launch vehicles to replace ground personnel and infrastructure needed to terminate flight or destruct the vehicle should an anomaly occur. This automation uses on-board real-time data and encoded logic to determine if the flight should be self-terminated. For uncrewed launch vehicles, FTS systems are required to protect the public and governed by the United States Space Force (USSF). For crewed missions, NASA must augment range AFTS requirements for crew safety and certify each flight according to human rating standards, thus adding unique requirements for reuse of software originally intended for uncrewed missions. This bulletin summarizes new information relating to AFTS to raise awareness of key distinctions, summarize considerations and outline best practices for incorporating AFTS into human-rated systems.
Key Distinctions – Crewed v. Uncrewed
There are inherent behavioral differences between uncrewed and crewed AFTS related to design philosophy and fault tolerance. Uncrewed AFTS generally favor fault tolerance against failure-to-destruct over failing silent
in the presence of faults. This tenet permeates the design, even downto the software unit level. Uncrewed AFTS become zero-fault-to-destruct tolerant to many unrecoverable AFTS errors, whereas general single fault
tolerance against vehicle destruct is required for crewed missions. Additionally, unique needs to delay destruction for crew escape, provide abort options and special rules, and assess human-in-the-loop insight, command, and/or override throughout a launch sequence must be considered and introduces additional requirements and integration complexities.
AFTS Software Architecture Components and Best-Practice Use Guidelines
A detailed study of the sole AFTS currently approved by USSF and utilized/planned for several launch vehicles was conducted to understand its characteristics, and any unique risk and mitigation techniques for effective human-rating reuse. While alternate software systems may be designed in the future, this summary focuses on an architecture employing the Core Autonomous Safety Software (CASS). Considerations herein are intended for extrapolation to future systems. Components of the AFTS software architecture are shown, consisting of the CASS, “Wrapper”, and Mission Data Load (MDL) along with key characteristics and use guidelines. A more comprehensive description of each and recommendations for developmental use is found in Ref. 1.
Best Practices Certifying AFTS Software
Below are non-exhaustive guidelines to help achieve a human-rating
certification for an AFTS.
References
NASA/TP-20240009981: Best Practices and Considerations for Using
Autonomous Flight Termination Software In Crewed Launch Vehicles
https://ntrs.nasa.gov/citations/20240009981 “Launch Safety,” 14 C.F.R., § 417 (2024). NPR 8705.2C, Human-Rating Requirements for Space Systems, Jul 2017,
nodis3.gsfc.nasa.gov/ NASA Software Engineering Requirements, NPR 7150.2D, Mar 2022,
nodis3.gsfc.nasa.gov/ RCC 319-19 Flight Termination Systems Commonality Standard, White
Sands, NM, June 2019. “Considerations for Software Fault Prevention and Tolerance”, NESC
Technical Bulletin No. 23-06 https://ntrs.nasa.gov/citations/20230013383 “Safety Considerations when Repurposing Commercially Available Flight
Termination Systems from Uncrewed to Crewed Launch Vehicles”, NESC
Technical Bulletin No. 23-02 https://ntrs.nasa.gov/citations/20230001890 View the full article
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By NASA
This artist’s concept shows interstellar object 1I/2017 U1 (‘Oumuamua) after its discovery in 2017. While itself not a dark comet, ‘Oumuamua’s motion through the solar system has helped researchers better understand the nature of the 14 dark comets discovered so far.European Southern Observatory / M. Kornmesser These celestial objects look like asteroids but act like comets now come in two flavors.
The first dark comet — a celestial object that looks like an asteroid but moves through space like a comet — was reported less than two years ago. Soon after, another six were found. In a new paper, researchers announce the discovery of seven more, doubling the number of known dark comets, and find that they fall into two distinct populations: larger ones that reside in the outer solar system and smaller ones in the inner solar system, with various other traits that set them apart.
The findings were published on Monday, Dec. 9, in the Proceedings of the National Academy of Sciences.
Scientists got their first inkling that dark comets exist when they noted in a March 2016 study that the trajectory of “asteroid” 2003 RM had moved ever so slightly from its expected orbit. That deviation couldn’t be explained by the typical accelerations of asteroids, like the small acceleration known as the Yarkovsky effect.
“When you see that kind of perturbation on a celestial object, it usually means it’s a comet, with volatile material outgassing from its surface giving it a little thrust,” said study coauthor Davide Farnocchia of NASA’s Jet Propulsion Laboratory in Southern California. “But try as we might, we couldn’t find any signs of a comet’s tail. It looked like any other asteroid — just a pinpoint of light. So, for a short while, we had this one weird celestial object that we couldn’t fully figure out.”
Weird Celestial Objects
Farnocchia and the astronomical community didn’t have to wait long for another piece of the puzzle. The next year, in 2017, a NASA-sponsored telescope discovered history’s first documented celestial object that originated outside our solar system. Not only did 1I/2017 U1 (‘Oumuamua) appear as a single point of light, like an asteroid, its trajectory changed as if it were outgassing volatile material from its surface, like a comet.
“‘Oumuamua was surprising in several ways,” said Farnocchia. “The fact that the first object we discovered from interstellar space exhibited similar behaviors to 2003 RM made 2003 RM even more intriguing.”
By 2023, researchers had identified seven solar system objects that looked like asteroids but acted like comets. That was enough for the astronomical community to bestow upon them their own celestial object category: “dark comets.” Now, with the finding of seven more of these objects, researchers could start on a new set of questions.
“We had a big enough number of dark comets that we could begin asking if there was anything that would differentiate them,” said Darryl Seligman, a postdoctoral fellow in the department of Physics at Michigan State University, East Lansing, and lead author of the new paper. “By analyzing the reflectivity,” or albedo, “and the orbits, we found that our solar system contains two different types of dark comets.”
Two Kinds of Dark Comets
The study’s authors found that one kind, which they call outer dark comets, have similar characteristics to Jupiter-family comets: They have highly eccentric (or elliptical) orbits and are on the larger side (hundreds of meters or more across).
The second group, inner dark comets, reside in the inner solar system (which includes Mercury, Venus, Earth, and Mars), travel in nearly circular orbits, and are on the smaller side (tens of meters or less).
Like so many astronomical discoveries, Seligman and Farnocchia’s research not only expands on our knowledge of dark comets, but it also raises several additional questions: Where did dark comets originate? What causes their anomalous acceleration? Could they contain ice?
“Dark comets are a new potential source for having delivered the materials to Earth that were necessary for the development of life,” said Seligman. “The more we can learn about them, the better we can understand their role in our planet’s origin.”
For more information about asteroids and comets, visit:
https://www.jpl.nasa.gov/topics/asteroids/
Small Body Research at JPL NASA Learns More About Interstellar Visitor 'Oumuamua Lesson: Comet on a Stick News Media Contacts
Ian J. O’Neill
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-2649
ian.j.oneill@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
Bethany Mauger
Michigan State University, East Lansing
maugerbe@msu.edu
2024-168
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Last Updated Dec 09, 2024 Related Terms
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By European Space Agency
Researchers from the University of Leeds have detected methane leaking from a faulty pipe in Cheltenham, Gloucestershire, UK, using GHGSat satellite data – part of ESA’s Third Party Mission Programme. This marks the first time a UK methane emission has been identified from space and successfully mitigated.
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By NASA
Hubble Space Telescope Home Hubble Spots a Spiral in the… Hubble Space Telescope Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Online Activities Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More 35th Anniversary 2 min read
Hubble Spots a Spiral in the Celestial River
This NASA/ESA Hubble Space Telescope image features the spiral galaxy NGC 1637. ESA/Hubble & NASA, D. Thilker The subject of this NASA/ESA Hubble Space Telescope image is NGC 1637, a spiral galaxy located 38 million light-years from Earth in the constellation Eridanus, the River.
This image comes from an observing program dedicated to studying star formation in nearby galaxies. Stars form in cold, dusty gas clouds that collapse under their own gravity. As young stars grow, they heat their nurseries through starlight, winds, and powerful outflows. Together, these factors play a role in controlling the rate at which future generations of stars form.
NGC 1637 holds evidence of star formation scattered throughout its disk, if you know where to look. The galaxy’s spiral arms have pockets of pink clouds, many with bright blue stars. The pinkish color comes from hydrogen atoms excited by ultraviolet light from young, massive stars forming within the clouds. This contrasts with the warm yellow glow of the galaxy’s center, which is home to a densely packed collection of older, redder stars.
The stars that set their cloudy birthplaces aglow are comparatively short-lived, and many of these stars will explode as supernovae just a few million years after they’re born. In 1999, NGC 1637 played host to a supernova named SN 1999EM, lauded as the brightest supernova seen that year. When a massive star expires as a supernova, the explosion outshines its entire home galaxy for a short time. While a supernova marks the end of a star’s life, it can also jump start the formation of new stars by compressing nearby clouds of gas, beginning the stellar lifecycle anew.
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Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
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Last Updated Dec 05, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Galaxies Goddard Space Flight Center Hubble Space Telescope Spiral Galaxies Stars Supernovae View the full article
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