#AceNewsReport – Dec.05: NASA has its eye on Asteroid 4660 Nereus because it’s well over 492 foot long and will come within 4.6 million miles (7.4 million km) of Earth. That puts it in the “potentially hazardous” category.
#AceDailyNews says that NASA says ‘concerning’ asteroid as big as a football field will break into Earth’s orbit in days: The huge 1082 foot (330 metre) space rock, which is as big as a football field, is heading our way and should skim past us on December 11, The Sun reports.
#AceNewsReport – Nov.25: NASA’s Double Asteroid Redirection Test (DART), the world’s first full-scale mission to test technology for defending Earth against potential asteroid or comet hazards, launched Wednesday at 1:21 a.m. EST on a SpaceX Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base in California.
#AceDailyNews DART NASA/SpaceX Launch Report: First Test Mission to Defend Planet Earth By CRASHING into an ASTEROID at 15,000-MPH ….
Just one part of NASA’s larger planetary defense strategy, DART – built and managed by the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland – will impact a known asteroid that is not a threat to Earth. Its goal is to slightly change the asteroid’s motion in a way that can be accurately measured using ground-based telescopes.
DART will show that a spacecraft can autonomously navigate to a target asteroid and intentionally collide with it – a method of deflection called kinetic impact. The test will provide important data to help better prepare for an asteroid that might pose an impact hazard to Earth, should one ever be discovered. LICIACube, a CubeSat riding with DART and provided by the Italian Space Agency (ASI), will be released prior to DART’s impact to capture images of the impact and the resulting cloud of ejected matter. Roughly four years after DART’s impact, ESA’s (European Space Agency) Hera project will conduct detailed surveys of both asteroids, with particular focus on the crater left by DART’s collision and a precise determination of Dimorphos’ mass.
“DART is turning science fiction into science fact and is a testament to NASA’s proactivity and innovation for the benefit of all,” said NASA Administrator Bill Nelson. “In addition to all the ways NASA studies our universe and our home planet, we’re also working to protect that home, and this test will help prove out one viable way to protect our planet from a hazardous asteroid should one ever be discovered that is headed toward Earth.”
At 2:17 a.m., DART separated from the second stage of the rocket. Minutes later, mission operators received the first spacecraft telemetry data and started the process of orienting the spacecraft to a safe position for deploying its solar arrays. About two hours later, the spacecraft completed the successful unfurling of its two, 28-foot-long, roll-out solar arrays. They will power both the spacecraft and NASA’s Evolutionary Xenon Thruster – Commercial ion engine, one of several technologies being tested on DART for future application on space missions.
“At its core, DART is a mission of preparedness, and it is also a mission of unity,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “This international collaboration involves DART, ASI’s LICIACube, and ESA’s Hera investigations and science teams, which will follow up on this groundbreaking space mission.”
DART’s one-way trip is to the Didymos asteroid system, which comprises a pair of asteroids. DART’s target is the moonlet, Dimorphos, which is approximately 530 feet (160 meters) in diameter. The moonlet orbits Didymos, which is approximately 2,560 feet (780 meters) in diameter.
Since Dimorphos orbits Didymos at much a slower relative speed than the pair orbits the Sun, the result of DART’s kinetic impact within the binary system can be measured much more easily than a change in the orbit of a single asteroid around the Sun.
“We have not yet found any significant asteroid impact threat to Earth, but we continue to search for that sizable population we know is still to be found. Our goal is to find any possible impact, years to decades in advance, so it can be deflected with a capability like DART that is possible with the technology we currently have,” said Lindley Johnson, planetary defense officer at NASA Headquarters. “DART is one aspect of NASA’s work to prepare Earth should we ever be faced with an asteroid hazard. In tandem with this test, we are preparing the Near-Earth Object Surveyor Mission, an space-based infrared telescope scheduled for launch later this decade and designed to expedite our ability to discover and characterize the potentially hazardous asteroids and comets that come within 30 million miles of Earth’s orbit.”
The spacecraft will intercept the Didymos system between Sept. 26 and Oct. 1, 2022, intentionally slamming into Dimorphos at roughly 4 miles per second (6 kilometers per second). Scientists estimate the kinetic impact will shorten Dimorphos’ orbit around Didymos by several minutes. Researchers will precisely measure that change using telescopes on Earth. Their results will validate and improve scientific computer models critical to predicting the effectiveness of the kinetic impact as a reliable method for asteroid deflection.
“It is an indescribable feeling to see something you’ve been involved with since the ‘words on paper’ stage become real and launched into space,” said Andy Cheng, one of the DART investigation leads at Johns Hopkins APL and the individual who came up with the idea of DART. “This is just the end of the first act, and the DART investigation and engineering teams have much work to do over the next year preparing for the main event ─ DART’s kinetic impact on Dimorphos. But tonight we celebrate!”
DART’s single instrument, the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO), will turn on a week from now and provide first images from the spacecraft. DART will continue to travel just outside of Earth’s orbit around the Sun for the next 10 months until Didymos and Dimorphos will be a relatively close 6.8 million miles (11 million kilometers) from Earth.
A sophisticated guidance, navigation, and control system, working together with algorithms called Small-body Maneuvering Autonomous Real Time Navigation (SMART Nav), will enable the DART spacecraft to identify and distinguish between the two asteroids. The system will then direct the spacecraft toward Dimorphos. This process will all occur within roughly an hour of impact.
Johns Hopkins APL manages the DART mission for NASA’s Planetary Defense Coordination Office as a project of the agency’s Planetary Missions Program Office. NASA provides support for the mission from several centers, including the Jet Propulsion Laboratory in Southern California, Goddard Space Flight Center in Greenbelt, Maryland, Johnson Space Center in Houston, Glenn Research Center in Cleveland, and Langley Research Center in Hampton, Virginia. The launch is managed by NASA’s Launch Services Program, based at the agency’s Kennedy Space Center in Florida. SpaceX is the launch services provider for the DART mission.
MailOnline Report: Videos: NASA launches spacecraft to test asteroid defense concept
17:00, 24 November 2021
Although the 525ft-wide space rock doesn’t pose a danger to Earth, NASA wants to measure the asteroid’s altered orbit caused by the collision.
NASA launches DART on SpaceX Falcon rocket to redirect an asteroid
WHAT IS THE NASA DART MISSION?
DART will be the world’s first planetary defence test mission.
It is heading for the small moonlet asteroid Dimorphos, which orbits a larger companion asteroid called Didymos.
When it gets there it will be intentionally crashing into the asteroid to slightly change its orbit.
While neither asteroid poses a threat to Earth, DART’s kinetic impact will prove that a spacecraft can autonomously navigate to a target asteroid and kinetically impact it.
Then, using Earth-based telescopes to measure the effects of the impact on the asteroid system, the mission will enhance modeling and predictive capabilities to help us better prepare for an actual asteroid threat should one ever be discovered.
‘This isn’t going to destroy the asteroid. It’s just going to give it a small nudge,’ said mission official Nancy Chabot of Johns Hopkins Applied Physics Laboratory, which is managing the project.
Dimorphos completes an orbit around Didymos every 11 hours and 55 minutes ‘just like clockwork’, she added.
The pair are no danger to Earth but offer scientists a way to measure the effectiveness of the collision.
DART’s goal is a crash that will slow Dimorphos down and cause it to fall closer toward the bigger asteroid, shaving 10 minutes off its orbit.
The change in the orbital period will be measured by telescopes on Earth. The minimum change for the mission to be considered a success is 73 seconds.
The DART technique could prove useful for altering the course of an asteroid years or decades before it bears down on Earth with the potential for catastrophe.
A small nudge ‘would add up to a big change in its future position, and then the asteroid and the Earth wouldn’t be on a collision course,’ NASA said.
Scientists constantly search for asteroids and plot their courses to determine whether they could hit the planet.
‘Although there isn’t a currently known asteroid that’s on an impact course with the Earth, we do know that there is a large population of near-Earth asteroids out there,’ said Lindley Johnson, NASA’s Planetary Defense Officer.
‘The key to planetary defence is finding them well before they are an impact threat.
‘We don’t want to be in a situation where an asteroid is headed towards Earth and then have to test this capability.’
#AceNewsReport – Oct.24: Past telescope observations from Earth had suggested the presence of large swaths of fine-grained material smaller than a few centimeters called fine regolith. …
#AceDailyNews reports that NASA Scientists thought Bennu’s surface was like a sandy beach, abundant in fine sand and pebbles, which would have been perfect for collecting samples:
But when NASA’s OSIRIS-REx mission arrived at Bennu in late 2018, the mission saw a surface covered in boulders. The mysterious lack of fine regolith became even more surprising when mission scientists observed evidence of processes potentially capable of grinding boulders into fine regolith.
New research, published in Nature and led by Saverio Cambioni, of the University of Arizona, used machine learning and surface temperature data to solve the mystery. Cambioni conducted the research at the university’s Lunar and Planetary Laboratory. He and his colleagues ultimately found that Bennu’s highly porous rocks are responsible for the surface’s surprising lack of fine regolith.
“The ‘REx’ in OSIRIS-REx stands for Regolith Explorer, so mapping and characterizing the surface of the asteroid was a main goal,” said study co-author and OSIRIS-REx Principal Investigator Dante Lauretta, a Regents Professor of Planetary Sciences at the University of Arizona. “The spacecraft collected very high-resolution data for Bennu’s entire surface, which was down to 3 millimeters per pixel at some locations. Beyond scientific interest, the lack of fine regolith became a challenge for the mission itself, because the spacecraft was designed to collect such material.”
A Rocky Start and Solid Answers
“When the first images of Bennu came in, we noted some areas where the resolution was not high enough to see whether there were small rocks or fine regolith. We started using our machine learning approach to distinguish fine regolith from rocks using thermal emission (infrared) data,” Cambioni said.
The thermal emission from fine regolith is different from that of larger rocks, because the size of its particles controls the former, while the latter is controlled by rock porosity. The team first built a library of thermal emissions associated with fine regolith mixed in different proportions with rocks of various porosity. Next, they used machine-learning techniques to teach a computer how to “connect the dots” between the examples, Cambioni said. They analyzed 122 areas on the surface of Bennu, that were observed both during the day and the night.
” Only machine learning could efficiently explore a dataset this large,” Cambioni said.
Cambioni and his collaborators found something surprising when the data analysis was completed: the fine regolith was not randomly distributed on Bennu. Instead, it was up to several tens of percent in those very few areas where rocks are non-porous, and systematically lower where rocks have higher porosity, which is most of the surface.
The team concluded that very little fine regolith is produced from Bennu’s highly porous rocks because these are compressed rather than fragmented by meteoroid impacts. Like a sponge, the voids within rocks cushion the blow from incoming meteoroids. These findings are also in agreement with laboratory experiments from other research groups.
“Basically, a big part of the energy of the impact goes into crushing the pores restricting the fragmentation of the rocks and the production of new fine regolith,” said study co-author Chrysa Avdellidou, a postdoctoral researcher at the French National Centre for Scientific Research (CNRS) – Lagrange Laboratory of the Côte d’Azur Observatory and University in France. Additionally, Cambioni and colleagues showed that cracking caused by the heating and cooling of Bennu’s rocks as the asteroid rotates through day and night proceeds more slowly in porous rocks than in denser rocks, further frustrating the production of fine regolith.
“When OSIRIS-REx delivers its sample of Bennu (to Earth) in September 2023, scientists will be able to study the samples in detail,” said Jason Dworkin, OSIRIS-REx project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This includes testing the physical properties of the rocks to verify this study.”
Other missions have evidence to support the team’s findings. The Japan Aerospace and Exploration Agency (JAXA) Hayabusa2 mission to Ryugu, a carbonaceous asteroid like Bennu, found that Ryugu also lacks fine regolith and has high-porosity rocks. Conversely, JAXA’s Hayabusa mission in 2005 revealed abundant fine regolith on the surface of asteroid Itokawa, an S-type asteroid with rocks of a different composition than Bennu and Ryugu. A previous study also from Cambioni and colleagues provided evidence that its rocks are less porous than Bennu’s and Ryugu’s using observations from Earth.
“For decades, astronomers disputed that small, near-Earth asteroids could have bare-rock surfaces,” said study co-author Marco Delbo, research director with CNRS, also at the Lagrange Laboratory. “The most indisputable evidence that these small asteroids could have substantial fine regolith emerged when spacecraft visited S-type asteroids Eros and Itokawa in the 2000s and found fine regolith on their surfaces.”
The team predicts that large swaths of fine regolith should be uncommon on carbonaceous asteroids, the most common of all asteroid types observed, and which the team expects to have high-porosity rocks like Bennu. By contrast, they predict terrains rich in fine regolith to be common on S-type asteroids, the second-most populous type of asteroids observed in the solar system, which they expect to have denser, less porous rocks than carbonaceous asteroids.
“This is an important piece in the puzzle of what drives the diversity of asteroids’ surfaces,” Cambioni said. “Asteroids are thought to be relics of the early solar system, so understanding the evolution they have undergone in time is crucial to comprehend how the solar system formed and evolved. Now that we know this fundamental difference between carbonaceous and S-type asteroids, future teams can better prepare sample collection missions depending on the nature of the target asteroid.”
Cambioni is continuing his research on planetary diversity as a distinguished postdoctoral fellow in the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology.
The University of Arizona leads the OSIRIS-REx science team and the mission’s science observation planning and data processing. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Lockheed Martin Space in Littleton, Colorado, built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate at NASA Headquarters in Washington, D.C.
#AceNewsReport – Oct.17: Lucy will investigate these “fossils” of planetary formation up close during its journey: Lucy embodies NASA’s enduring quest to push out into the cosmos for the sake of exploration and science, to better understand the universe and our place within it,” said NASA Administrator Bill Nelson. “I can’t wait to see what mysteries the mission uncovers!”…….
#AceDailyNews reports that NASA, ULA Launch Lucy Mission to ‘Fossils’ of Planet Formation: NASA’s Lucy mission, the agency’s first to Jupiter’s Trojan asteroids, launched at 5:34 a.m. EDT Saturday on a United Launch Alliance (ULA) Atlas V rocket from Space Launch Complex 41 at Cape Canaveral Space Force Station in Florida.
About an hour after launch, Lucy separated from the second stage of the ULA Atlas V 401 rocket. Its two massive solar arrays, each nearly 24 feet (7.3 meters) wide, successfully unfurled about 30 minutes later and began charging the spacecraft’s batteries to power its subsystems.
“Today’s launch marks a genuine full-circle moment for me as Lucy was the first mission I approved in 2017, just a few months after joining NASA,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at the agency’s Headquarters in Washington. “A true mission of discovery, Lucy is rich with opportunity to learn more about these mysterious Trojan asteroids and better understand the formation and evolution of the early solar system.”
Lucy sent its first signal to Earth from its own antenna to NASA’s Deep Space Network at 6:40 a.m. The spacecraft is now traveling at roughly 67,000 mph (108,000 kph) on a trajectory that will orbit the Sun and bring it back toward Earth in October 2022 for a gravity assist.
Named for the fossilized skeleton of one of our earliest known hominin ancestors, the Lucy mission will allow scientists to explore two swarms of Trojan asteroids that share an orbit around the Sun with Jupiter. Scientific evidence indicates that Trojan asteroids are remnants of the material that formed giant planets. Studying them can reveal previously unknown information about their formation and our solar system’s evolution in the same way the fossilized skeleton of Lucy revolutionized our understanding of human evolution.
“We started working on the Lucy mission concept early in 2014, so this launch has been long in the making,” said Hal Levison, Lucy principal investigator, based out of the Boulder, Colorado, branch of Southwest Research Institute (SwRI), which is headquartered in San Antonio. “It will still be several years before we get to the first Trojan asteroid, but these objects are worth the wait and all the effort because of their immense scientific value. They are like diamonds in the sky.”
Lucy’s Trojan destinations are trapped near Jupiter’s Lagrange points – gravitationally stable locations in space associated with a planet’s orbit where smaller masses can be trapped. One swarm of Trojans is ahead of the gas giant planet, and another is behind it. The asteroids in Jupiter’s Trojan swarms are as far away from Jupiter as they are from the Sun.
The spacecraft’s first Earth gravity assist in 2022 will accelerate and direct Lucy’s trajectory beyond the orbit of Mars. The spacecraft will then swing back toward Earth for another gravity assist in 2024, which will propel Lucy toward the Donaldjohanson asteroid – located within the solar system’s main asteroid belt – in 2025.
Lucy will then journey toward its first Trojan asteroid encounter in the swarm ahead of Jupiter for a 2027 arrival. After completing its first four targeted flybys, the spacecraft will travel back to Earth for a third gravity boost in 2031, which will catapult it to the trailing swarm of Trojans for a 2033 encounter.
“Today we celebrate this incredible milestone and look forward to the new discoveries that Lucy will uncover,” said Donya Douglas-Bradshaw, Lucy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
NASA Goddard provides overall mission management, systems engineering, plus safety and mission assurance. Lockheed Martin Space in Littleton, Colorado, built the spacecraft. Lucy is the 13th mission in NASA’s Discovery Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Discovery Program for the agency.