Strange, dark-veined meteorites rained down on Earth when a fireball exploded over Chelyabinsk, Russia, in February 2013. The origin of these unusual meteorites has remained a mystery, but now, planetary scientists have discovered a possible source: a mile-and-a-half-long near-Earth asteroid.
Scientists know that the dark streaks across the Chelyabinsk meteorites are caused by a process called shock darkening. Yet only around 2% of a common type of meteorite called chondrite meteorites show signs of shock darkening, and the source of these space rocks has remained a mystery.
Now, scientists have identified the asteroid 1998 OR2 as a potential source of shock-darkened meteorites. The near-Earth asteroid was discovered in July 1998 by the Near-Earth Asteroid Tracking program at NASA’s Jet Propulsion Laboratory. Its last close approach to Earth was in April 2020, when the space rock passed within 3.9 million miles (6.3 million kilometers) of our planet.
Although that may not seem very close, NASA still considers 1998 OR2 “potentially hazardous” because changes to the asteroid’s orbit over the next 1,000 years could make it a risk to Earth.
Meteorites are created when pieces of an asteroid like 1998 OR2 break away and enter Earth’s atmosphere. The discovery that shock-darkened meteorites can originate from a near-Earth asteroid hints at the varying material strength of asteroids and has implications for protecting Earth against a potential impact, the researchers said.
“Shock darkening is an alteration process caused when something impacts a planetary body hard enough that the temperatures partially or fully melt those rocks and alter their appearance both to the human eye and in our data,” Adam Battle, a graduate student in planetary science at the University of Arizona and lead author of the study, said in a statement (opens in new tab). “This process has been seen in meteorites many times but has only been seen on asteroids in one or two cases way out in the main asteroid belt, which is found between Mars and Jupiter.”
Vishnu Reddy, a planetary scientist at the University of Arizona and co-author of the new study who detected shock darkening on these main-belt asteroids, said that it’s a much more common phenomenon on asteroids than meteorites. “Impacts are very common in asteroids and any solid body in the solar system because we see impact craters on these objects from spacecraft images,” he said in the statement. “But impact melt and shock-darkening effects on meteorites derived from these bodies are rare.”
Reddy, who co-leads the Space Domain Awareness lab at the Lunar and Planetary Laboratory, added that finding a near-Earth asteroid dominated by this process has implications for impact hazard assessment.
“Adam [Battle]’s work has shown that ordinary chondrite asteroids can appear as carbonaceous in our classification tools if they are affected by shock darkening,” Reddy said. “These two materials have different physical strengths, which is important when trying to deflect a hazardous asteroid.”
Is asteroid 1998 OR2 chondrite or carbonaceous?
Reddy, Battle and their team used the Rapid Astronomical Pointing Telescopes for Optical Reflectance Spectroscopy (RAPTORS) atop the Kuiper Space Sciences Building on the University of Arizona campus to observe the asteroid 1998 OR2.
The team collected data on 1998 OR2’s surface composition, with the asteroid visually appearing as an ordinary chondrite asteroid, a type of space rock that is light in color and contains the minerals olivine and pyroxene. But an asteroid classification tool determined that 1998 OR2 appeared to be a carbonaceous asteroid ; these space rocks are dark and featureless compared with chondrite asteroids.
The team then set about investigating the reason for this discrepancy and determining the correct classification.
“The mismatch was one of the early things that got the project going to investigate potential causes for the discrepancy,” Battle said.
They eliminated the possibility that exposure to the space environment had caused changes in the asteroid’s surface, as this process, called space weathering, would have left the space rock slightly reddened.
The team concluded that shock darkening was responsible for the disparity between the two analysis methods, because the shock darkening process can obscure olivine and pyroxene while darkening the asteroid’s surface, thus making it look like a carbonaceous asteroid.
“The asteroid is not a mixture of ordinary chondrite and carbonaceous asteroids, but rather it is definitely an ordinary chondrite, based on its mineralogy, which has been altered — likely through the shock darkening process — to look like a carbonaceous asteroid to the classification tool,” Battle said.
Shock darkening of asteroids was first theorized in the late 20th century but wasn’t an intense area of study until the 2013 Chelyabinsk fireball seeded Earth with shock-darkened meteorites.
Interest in shock darkening grew after Reddy found asteroids affected by the process in the main asteroid belt. This new discovery showing evidence of the process in a near-Earth asteroid could further increase interest in shock darkening, the team said.
The research was published Oct. 4 in The Planetary Science Journal and presented at a conference held this week by the American Astronomical Society’s Division of Planetary Sciences..
NASA's Artemis 1, Over 400,000 Kms From Earth, Sets A New Record – NDTV
NASA’s Artemis 1 Orion has set a new record for the spacecraft designed to carry humans to deep space by travelling 419,378 kilometres from Earth. The record was previously set during the Apollo 13 mission at 248,655 miles from our home planet.
For the next six days, Orion will remain in lunar orbit. It will then put the spacecraft on a trajectory back to Earth, followed by a Sunday, December 11, splashdown in the Pacific Ocean, a press release by NASA said.
Mission Time: 11 days, 4 hrs, 27 min
Orion is 260,590 miles from Earth, 48,345 miles from the Moon, cruising at 1,852 miles per hour.
P: (133334, -199119, -112070)
V: (1774, 512, 140)
O: 335º, 3.1º, 305.6º
What’s this? https://t.co/voR4yGy2mg#TrackArtemispic.twitter.com/OM7HlUbMnE
— Orion Spacecraft (@NASA_Orion) November 27, 2022
NASA, in a build-up to the landmark event, said, “Today, NASA Orion Spacecraft will break the record for farthest distance of a spacecraft designed to carry humans to deep space and safely return them to Earth. This record is currently held by Apollo 13.” The text was attached to a video featuring the Apollo astronauts and flight directors who spoke about the future of Artemis. Take a look:
Today, @NASA_Orion will break the record for farthest distance of a spacecraft designed to carry humans to deep space and safely return them to Earth. This record is currently held by Apollo 13.
— NASA (@NASA) November 26, 2022
NASA is expected to use innovative measures to learn more about the Moon’s South Pole. The agency will also try to understand the lunar surface with the help of the Gateway Space Station in orbit, the press note added.
The spacecraft has a sensor named Commander Moonikin Campos attached to it. It will help provide information on what crew members may experience in flight. The Campos is named after Arturo Campos, the key player in bringing Apollo 13 safely back to Earth.
Answering questions at a discussion conducted by NASA on Twitter, Jim Geffre, Orion’s spacecraft integration manager, said, “Artemis 1 was designed to stress the systems of Orion and we settled on the distant retrograde orbit as a really good way to do that.”
Featured Video Of The Day
YouTuber Mark Rober drops eggs from space to land in Victor Valley – VVdailypress.com
The 42-year-old Rober and his team of scientists dropped both eggs, with the intention of them not breaking, from a height of nearly 19 miles and with the help of a high-altitude balloon provided by Night Crew Labs.
The launch occurred earlier this year, but the “Egg Drop From Space” video was uploaded to YouTube on Black Friday.
It includes shots of the team driving on Bear Valley Road toward Deadman’s Point in Apple Valley. Also shown are Bell Mountain, Interstate 15 and an area west of I-15 and near the Dale Evans Parkway offramp.
A shot from the weather balloon in space showed the Victor Valley, including landmarks such as Spring Valley Lake and the Mojave River.
The egg-drop project
When Rober started conceptualizing his egg drop project nearly three years ago, he knew that a successful record drop would come from his experience of landing scientific gear on other planets when he worked for NASA.
A graduate of USC, Rober worked at NASA for nine years, seven of them on the Mars Curiosity project. He also spent five years at Apple working on advanced virtual reality technology for autonomous vehicles before quitting to become a full-time YouTuber.
Rober confessed that before he embarked on the egg drop project, he didn’t know that it would be the most “physically, financially and mentally draining video” he would ever attempt.
Rober’s team included rocket and propulsion specialist Joe Barnard, of BPS Systems, which helped with the rocket’s guidance system and design.
Rober’s original plan was to affix an egg onto a rocket, which would be lifted by a large weather balloon. Once in space, the rocket would be released and would guide the rocket to an area over the drop target.
At 300 feet above the ground, the egg would be released and free-fall toward a specially designed mattress.
After determining the terminal velocity of the egg to be 74 mph, he successfully tested the speed inside his Crunch Lab located near San Francisco
Rober and his team then headed to the Northern California town of Gridley for three low-altitude tests, which all failed.
‘A fatal flaw’
Rober sought the guidance of NASA engineer Adam Steltzner, who works for the Jet Propulsion Laboratory and on several flight projects including Galileo, Cassini, Mars Pathfinder and the Mars Exploration Rovers.
After listening to Rober and details about his project, Steltzner found a “fatal flaw” in the project and asked him, “How did you not get busted by the FAA?”
Rober realized that his project was akin to creating a precision-guided missile, which is frowned upon by the federal government.
Heading to the High Desert
After going back to the drawing board, Rober’s team decided to conduct a rocket launch with a general egg drop target area in the High Desert.
The launch would use a weather balloon, which would lift a larger and heavier rocket to guarantee the egg would reach supersonic speed on its way down.
The helium-filled balloon would release the rocket, which would begin separating.
A portion of the rocket, carrying the egg, would slow before losing its nose cone and deploying a parachute and cushioned airbags, which were borrowed from the Spirit and Opportunity landing projects.
Just before liftoff, Rober discovered that the newly designed, the two-piece rocket might unexpectedly separate at Mach 2.
Rober and his team fixed the rocket’s connection point and ran vacuum and heat tests on the egg chamber.
They also built redundancy into the system, which included creating a custom beach ball, filled with packing materials to protect a second egg.
The entire payload, suspended from the balloon, would detach and simply fall to earth over the target.
Rober’s friend, JPL systems engineer Allen Chen, traveled to the Victor Valley for Rober’s second launch.
In 2012, Chen uttered the famous words, “Touchdown confirmed, we’re safe on Mars,” after the Curiosity Rover had survived the harrowing plunge and landed on the red planet.
Somewhere near Apple Valley, the lift-off of Rober’s balloon, rocket, beach ball and eggs was successful.
As the team drove and arrived at the projected landing site, they discovered that the balloon had surpassed the 100,000-foot mark.
As the group celebrated, moments later, they discovered that the balloon had suddenly lost altitude and came crashing down to earth.
As the balloon ascended, the cord that held the rocket, beach ball and eggs had wound so tight that it pulled down on the balloon, causing it to come hurtling down at 150 mph, “Which is way faster than the eggs could survive,” Rober explained.
As the team looked for the wreckage, they spotted the parachute, the rocket and the beach ball.
Rober was excited that at 20,000 feet, the payload had autonomously detached itself from the balloon.
Rober held back his excitement as he opened the rocket to inspect the egg.
As a smiling Rober pulled an uncracked egg from the rocket and held it high, Chen joyously said, “Touchdown confirmed, we’re safe on earth.”
That was repeated when Rober ripped open the beach ball and pulled out a second uncracked egg that he kissed.
“Two for two, baby!” shouted Rober as he high-fived Chen. “Two for two!”
Rober ended the video by saying that the egg drop from space project reminded him that in life things rarely unfold how we think they will.
“But by learning from your failures, coupled with a bit of tenacity, us humans can accomplish a feat as incredible as the world’s smartest Martian robot or as ridiculous as the world’s tallest egg drop,” Rober said.
Daily Press reporter Rene Ray De La Cruz may be reached at 760-951-6227 or RDeLaCruz@VVDailyPress.com. Follow him on Twitter @DP_ReneDeLaCruz
In a B.C. first, UVic mini-satellite launched into space after four years of work
A University of Victoria satellite the size of a two-litre milk carton, designed to calibrate light, was fired into space Saturday, after four years of work by dozens of students, faculty and researchers.
ORCASat started its journey to space at 11:20 a.m. Saturday as part of NASA’s SpaceX Falcon 9 rocket launch at Kennedy Space Center in Florida.
Early this morning, about 4 a.m., the satellite is scheduled to be taken on board the International Space Station where it will wait for a few weeks before being fired into space to orbit the Earth for as long as it can survive.
Saturday’s successful launch was extra-sweet because a planned Tuesday launch was postponed due to poor weather. Watchers from UVic returned home after the delayed launch.
A nervous Alex Doknjas, ORCASat project manager, went into his family’s living room at 10:30 a.m. Saturday where he waited with loved ones and about 20 others on a video chat, including a UVic group, to watch the event together. Cheers and claps erupted when the rocket launched on time. “It’s great. It’s fantastic,” he said.
There was a little wind picking up on the launch site shortly before liftoff was scheduled and Doknjas said he was worried it was about to get scrubbed again, but that didn’t happen.
The excitement has been years in the making thanks to about 140 people who have been part of a team at the University of Victoria Centre for Aerospace Research.
Full-time researchers, co-op and volunteer students from UVic Satellite Design, UBC Orbit, and Simon Fraser University Satellite Design have all contributed.
The ORCASat (for Optical Reference Calibration Satellite) measures 10 centimetres by 10 centimetres by 23 centimetres and weighs 2.5 kilograms.
Doknjas said as far as he knows this is the first “Cubesat” designed and built in this province. “That’s a pretty big milestone.”
The estimated date to launch ORCASat is between Dec. 29 and the first week in January.
ORCASat will be doing a 400-kilometre orbit around Earth and travelling at 7.5 kilometres a second. “It’s pretty fast.”
It is not known exactly how long it will last but it could be six to eight months, up to 18 months, Doknjas said. Factors such as sun flares, solar radiation, pressure and more can all impact the life of the satellite.
ORCASat is basically an artificial star, a reference light source in orbit that can be viewed by telescopes on Earth.
Astronomers can measure how bright ORCASat appears, just as they would an astronomical object.
At the same time, the satellite, using two laser light sources, will measure the amount of light that an astronomical object is emitting.
This will allow ground-based telescopes to be calibrated to measure the absolute brightness of an astronomical object, not how they appear after passing through the atmosphere and the optics of a telescope.
This is the first satellite ever to carry a light source capable of performing this experiment to this level of accuracy.
It is a proof-of-concept technology which in the future could be developed to be applicable in such areas as climate change, Earth observation and methane gas research, Doknjas said.
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