2023 BU will pass over the southern tip of South America on January 26. Illustration: NASA/JPL-Caltech
An asteroid is on its way to Earth, but don’t worry—the end is not here. The asteroid, dubbed 2023 BU, is about the size of a box truck and is not projected to impact our planet during its flyby on Thursday. However, it will be “one of the closest approaches by a known near-Earth object ever recorded,” according to a NASA scientist.
NASA’s Jet Propulsion Lab said in a release on Wednesday that 2023 BU is about 11.5 to 28 feet (3.5 to 8.5 meters) wide, which is small enough to mostly burn up in our atmosphere if it were to hit us. But NASA doesn’t expect 2023 BU to slam into the planet; instead the asteroid will pass about 2,200 miles (3,600 kilometers) above the southern tip of South America on Thursday, January 26, at 4:32 p.m. PST. NASA was able to calculate the position and trajectory of the asteroid using Near Earth Asteroid Scout, a hazard assessment system.
“Scout quickly ruled out 2023 BU as an impactor, but despite the very few observations, it was nonetheless able to predict that the asteroid would make an extraordinarily close approach with Earth,” said Davide Farnocchia, a navigation engineer at NASA Jet Propulsion Laboratory who developed Scout. “In fact, this is one of the closest approaches by a known near-Earth object ever recorded.”
2023 BU is passing closer to us then some of the satellites orbiting our planet, and Earth’s gravity is changing the asteroid’s path around the Sun from circular to more elongated. The asteroid was discovered by Gennadiy Borisov at the MARGO observatory in Nauchnyi, Crimea on January 21. Since then, observatories across the planet have also detected 2023 BU, leading to robust models of the asteroid’s path and potential hazard.
Astronomers’ detection of and prompt study of 2023 BU shows how robust humanity’s asteroid detection workflow is becoming. Our ability to eventually defend our planet is advancing, too, after the successful DART test mission to deflect asteroid last October.
The HAARP facility’s antenna array includes 180 antennas spread across 33 acres.Photo: HAARP
A group of researchers is attempting to bounce radio signals off a 500-foot-wide asteroid during its close flyby of Earth on Tuesday.
The High Frequency Active Auroral Research Program (HAARP) is aiming its antennas at asteroid 2010 XC15, a space rock that’s categorized as a near-Earth potentially hazardous asteroid. The effort is a test run to to prepare for a larger object, known as Apophis, that will have a close encounter with our planet in 2029.
“What’s new and what we are trying to do is probe asteroid interiors with long wavelength radars and radio telescopes from the ground,” Mark Haynes, lead investigator on the project and a radar systems engineer at NASA’s Jet Propulsion Laboratory in Southern California, said in a statement. “Longer wavelengths can penetrate the interior of an object much better than the radio wavelengths used for communication.”
HAARP is a research facility in Gakona, Alaska (one that’s been the subject of plenty of conspiracy theories). It’s made up of 180 high-frequency antennas, each standing at 72 feet tall and stretched across 33 acres. The facility transmits radio beams toward the ionosphere, the ionized part of the atmosphere that’s located about 50 to 400 miles (80 to 600 kilometers) above Earth’s surface. HAARP sends radio signals to the ionosphere and waits to see how they return, in an effort to measure the disturbances caused by the Sun, among other things.
The facility launched a science campaign in October with 13 experiments, including one that involved bouncing signals off the Moon. At the time, HAARP researchers were considering sending a radio signal to an asteroid to investigate the interior of the rocky body.
During today’s experiment, the HAARP antennas in Alaska will transmit the radio signals to the asteroid, and then scientists will check if the reflected signals arrive at antenna arrays at the University of New Mexico Long Wavelength Array and California’s Owens Valley Radio Observatory Long Wavelength Array.
HAARP will transmit a continually chirping signal at slightly above and below 9.6 megahertz; the chirp will repeat at two-second intervals. At its closest approach on December 27, the asteroid will be twice as far as the Moon is from Earth.
Tuesday’s experiment is to prepare for an upcoming encounter with an asteroid in 2029. That potentially hazardous asteroid, formally known as 99942 Apophis, is around 1,210 feet (370 meters) wide, and it will come to within 20,000 miles (32,000 kilometers) of Earth on April 13, 2029. The near-Earth object was thought to pose a slight risk to Earth in 2068, but NASA ruled that out.
Still, HAARP wants to probe the asteroid to prepare for potential risks in the future from space rocks. “The more time there is before a potential impact, the more options there are to try to deflect it,” Haynes said.
In September, NASA’s DART spacecraft smacked into a small asteroid and successfully altered its orbit. Such a strategy could be one way to divert a space rock that threatens Earth.
Today’s test shows the potential of using long wavelength radio signals to probe the interiors of asteroids. “If we can get the ground-based systems up and running, then that will give us a lot of chances to try to do interior sensing of these objects,” Haynes said.
More: A Powerful Recoil Effect Magnified NASA’s Asteroid Deflection Experiment
I aimed a 1,500-foot iron asteroid traveling at 38,000 miles per hour with a 45-degree impact angle at Gizmodo’s office in Midtown, Manhattan.Screenshot: Gizmodo/Neal.Fun
Hundreds of thousands of asteroids lurk in our solar system, and while space agencies track many of them, there’s always the chance that one will suddenly appear on a collision course with Earth. A new app on the website Neal.fun demonstrates what could happen if one smacked into any part of the planet.
Neal Agarwal developed Asteroid Simulator to show the potentially extreme local effects of different kinds of asteroids. The first step is to pick your asteroid, with choices of iron, stone, carbon, and gold, or even an icy comet. The asteroid’s diameter can be set up to 1 mile (1.6 kilometers); its speed can be anywhere from 1,000 to 250,000 miles per hour; and the impact angle can be set up to 90 degrees. Once you select a strike location on a global map, prepare for chaos.
“I grew up watching disaster movies like Deep Impact and Armageddon, and so I always wanted to make a tool that would let me visualize my own asteroid impact scenarios,” Agarwal said to Gizmodo in an email. “I think this tool is for anyone who loves playing out ‘what-if’ scenarios in their head. The math and physics behind the simulation is based on research papers by Dr. Gareth Collins and Dr. Clemens Rumpf who both study asteroid impacts.”
Once you’ve programmed the asteroid and launched it at your desired target, Asteroid Simulator will walk you through the devastation. First, it’ll show you the width and depth of the crater, the number of people vaporized by the impact, and how much energy was released. It will then walk you through the size and effects of the fireball, shock wave, wind speed, and earthquake generated by the asteroid.
NASA has its eyes on more than 19,000 near-Earth asteroids. While no known space rock poses an imminent threat to Earth, events like the 2013 Chelyabinsk impact in Russia remind us of the need for robust planetary defense. Just this year, NASA tested an asteroid deflection strategy via its DART spacecraft, to resounding success.
Composite image of the Didymos-Dimorphos system taken on November 30, showing its new ejecta tail. Image: Magdalena Ridge Observatory/NM Tech
Scientists continue to pore over the results of NASA’s stunningly successful DART test to deflect a harmless asteroid. As the latest findings suggest, the recoil created by the blast of debris spewing out from Dimorphos after impact was significant, further boosting the spacecraft’s influence on the asteroid.
NASA’s fridge-sized spacecraft smashed into the 535-foot-long (163-meter) Dimorphos on September 26, shortening its orbit around its larger partner, Didymos, by a whopping 33 minutes. That equates to several dozen feet, demonstrating the feasibility of using kinetic impactors as a means to deflect threatening asteroids.
A stunning side-effect of the test were the gigantic and complex plumes that emanated from the asteroid after impact. The Didymos-Dimorphos system, located 7 million miles (11 million kilometers) from Earth, even sprouted a long tail in the wake of the experiment. DART, short for Double Asteroid Redirection Test, had a profound impact on Dimorphos, kicking up a surprising amount of debris, or “ejecta,” in the parlance of planetary scientists.
Animated image showing changes to the Didymos-Dimorphos system in the first month following DART’s impact. Gif: University of Canterbury Ōtehīwai Mt. John Observatory/UCNZ
Dimorphos, as we learned, is a rubble pile asteroid, as opposed to it being a dense, tightly packed rocky body. This undoubtedly contributed to the excessive amount of ejected debris, but scientists weren’t entirely sure how much debris the asteroid shed as a result of the impact. Preliminary findings presented on Thursday at the American Geophysical Union’s Fall Meeting in Chicago are casting new light on this and other aspects of the DART mission.
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Not only did DART kick up tons of ejecta, it also triggered a recoil effect that further served to nudge the asteroid in the desired direction, as Andy Rivkin, DART investigation team lead, explained at the meeting. “We got a lot of bang for the buck,” he told BBC News.
Indeed, had Dimorphos been a more compact body, the same level of recoil likely wouldn’t have happened. “If you blast material off the target then you have a recoil force,” explained DART mission scientist Andy Cheng from the Johns Hopkins University Applied Physics Lab, who also spoke at the meeting. The resulting recoil is analogous to letting go of a balloon; as the air rushes out, it pushes the balloon in the opposite direction. In the case of Dimorphos, the stream of ejecta served as the air coming out of the balloon, which likewise pushed the asteroid in the opposite direction.
Planetary scientists are starting to get a sense as to how much debris got displaced. DART, traveling at 14,000 miles per hour (22,500 km/hour), struck with enough force to spill over 2 million pounds of material into the void. That’s enough to fill around six or seven rail cars, NASA said in a statement. That estimate might actually be on the low side, and the true figure could possibly be 10 times higher, Rivkin said at the meeting.
The scientists assigned DART’s momentum factor, known as “beta,” a value of 3.6, meaning that the momentum transferred into Dimorphos was 3.6 times greater than an impact event that produced no ejecta plume. “The result of that recoil force is that you put more momentum into the target, and you end up with a bigger deflection,” Cheng told reporters. “If you’re trying to save the Earth, this makes a big difference.”
That’s a good point, as those values will dictate the parameters for an actual mission to deflect a legitimately dangerous asteroid. Cheng and his colleagues will now use these results to infer the beta values of other asteroids, a task that will require a deeper understanding of an object’s density, composition, porosity, and other parameters. The scientists are also hoping to figure out the degree to which DART’s initial hit moved the asteroid and how much of its movement happened on account of the recoil.
The speakers also produced another figure—the length of the tail, or ejecta plume, that formed in the wake of the impact. According to Rivkin, Dimorophos sprouted a tail measuring 18,600 miles (30,000 km) long.
“Impacting the asteroid was just the start,” Tom Statler, the program scientist for DART and a presenter at the meeting, said in the statement. “Now we use the observations to study what these bodies are made of and how they were formed—as well as how to defend our planet should there ever be an asteroid headed our way.”
NASA warns that a 65-foot wide asteroid will be coming dangerously close to the Earth today, November 26. Know the consequences that a gigantic asteroid has.
When it comes to space, both exploration and protection is equally important for scientists and space agencies. That is why before the Artemis-1 mission, which is aiming to send crewed spacecraft back to the Moon to explore its polar region, NASA took up the Double Asteroid Redirection Test (DART) where a spacecraft was used to change the path of an asteroid. And the reason this test was done was because of many asteroids which threaten the Earth with their potential to destroy cities and even countries. One such asteroid will be paying a visit to the Earth today itself, November 26. Read on to know whether an asteroid strike is possible.
Scary asteroid to come very close to the Earth
The Planetary Defense of NASA is made up of multiple departments, all of which are tasked with monitoring the Near-Earth Objects (NEO). These departments include Center for Near Earth Objects Studies (CNEOS), Jet Propulsion Laboratory (JPL) and Small-Body database. The cumulative data from these departments has revealed quite a bit about this space rock. The asteroid is named 2022 UD72. It was first discovered recently in October 2022, and hence the four digit number in its name. The 65-foot asteroid will be coming as close as 4 million kilometers to the Earth. While that may seem like a large distance, traveling at a speed of 15,408 kilometers per hour, it can close that gap within days in case there is a last moment deflection.
However, the prediction by NASA at the moment is that there is little chance that 2022 UD72 will strike the Earth. It is expected that the asteroid will make a safe passage. However, various instruments will be monitoring it till it is at a safe distance from us.
NASA’s asteroid tracking technology
Ever since NASA understood the risk of the near-Earth objects (NEO), it has dedicated itself to track and monitor as many space rocks in the inner circle of the solar system as possible. Using the prowess of JPL and Wide-field Infrared Survey Explorer (WISE) telescope, the US space agency collects data for over 20,000 asteroids.
Last week, NASA’s DART spacecraft intentionally crashed into Dimorphos, a petite moonlet orbiting the larger asteroid Didymos. Now, a telescope on the ground in Chile has imaged the massive plume created by the impact in the days following the encounter.
The crash was a planetary defense test; NASA is seeking to know if a kinetic impactor can change the trajectory of an Earth-bound space rock, should we ever spot a large one on a collision course with us. The space agency’s Center for Near Earth Objects exists to monitor the status of these objects and their orbits.
NASA is still sifting through the data of the collision to determine if the Double Asteroid Redirection Test, or DART, altered Dimorphos’s orbital trajectory around its larger companion, but images of the impact are coming thick and fast from all the telescopic lenses turned towards the historic event.
The latest images come from the Southern Astrophysical Research (SOAR) Telescope in Chile, operated by NOIRLab. The SOAR telescope is located in the foothills of the Andes, an arid environment with clear, light-free skies that make the region ideal for ground-based telescopes.
The expanding dust trail from the collision is clearly visible, stretching to the right corner of the image. According to a NOIRLab release, the debris trail stretches about 6000 miles (10,000 kilometers) from the point of impact. Said Teddy Kareta, an astronomer at Lowell Observatory who was involved with the observation, in the release: “It is amazing how clearly we were able to capture the structure and extent of the aftermath in the days following the impact.”
NASA scientists have yet to come out with their determination on DART’s success, but the impact is a success in itself. Soon to come are further findings about the event: exactly how much material from Didymos was expelled, how pulverized the material was, and how fast it may have been kicked up. The data could shed important light on the effect that kinetic impactors might have on “rubble pile” asteroids, which Dimorphos appears to be. Rubble pile asteroids feature loosely bound conglomerations of surface material, which could explain these dramatic post-impact views of the moonlet.
Nearby in Chile, the Vera C. Rubin Observatory’s sky survey will soon begin. Among its charges are assessing potentially hazardous objects near Earth—though considering the recent test, perhaps the asteroids should be worried about us.
More: Ground Telescopes Capture Jaw-Dropping Views of DART Asteroid Impact
An artist’s depiction of the DART Spacecraft approaching the asteroid. Illustration: NASA
The demise of DART is finally upon us, as the NASA spacecraft is on a collision course with the tiny Dimorphos asteroid. Here’s how you can watch this hugely important experiment to deflect an asteroid.
Short for Double Asteroid Redirection Test, the DART mission is the first test of kinetic impactor technology as a means of deflecting asteroids that could be headed towards Earth. Although Didymos means no harm to our planet, the epic crash could one day protect our planet from an Earth-bound asteroid. A lot is resting on this astronomical encounter, and here’s how you can watch the action live.
The DART spacecraft is scheduled to impact its target asteroid on Monday at 7:14 p.m. ET. NASA will live stream the event at the space agency’s YouTube channel, the NASA app, and the agency’s website. Or you can stay right here and tune into the NASA broadcast through the feed below.
DART’s Impact with Asteroid Dimorphos (Official NASA Broadcast)
Live coverage of the mission will begin at 6 p.m. ET, and it will feature audio from NASA’s mission control, live commentary, as well as images beamed down by the spacecraft’s onboard high-resolution camera, DRACO (Didymos Reconnaissance and Asteroid Camera for Optical navigation).
Excitingly, NASA is also providing a silent live feed from DRACO that’s set to begin at 5 p.m. ET on NASA’s media channel. DRACO will keep rolling until it finally smashes into Dimorphos, relaying one image per second back to ground controllers on Earth. You can also tune in to the DRACO feed through the live stream below.
Watch a Live Feed from NASA’s DART Spacecraft on Approach to Asteroid Dimorphos
DART is careening towards the asteroid at speeds reaching 14,000 miles per hour (22,530 kilometers per hour). There may be a slight lag between these images and what’s happening in the control room as it takes about eight seconds for the images to appear on the screen after they’ve been received and processed by mission control, NASA officials told reporters during a press briefing on Thursday. So even if mission control declares “impact ” or “loss of signal,” it may take a few seconds to see that reflected in NASA’s coverage. And by “see it happen” we assume that’ll be the sudden appearance of a blank screen, signifying the destruction of the spacecraft.
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Alexa? Has an 8″ HD touchscreen which can let you watch shows, stream things, or even make video calls thanks to the 13 MP camera, you can also use it to control other smart devices in your home with ease, and even display photos if you want to as a digital photo frame.
DART is NASA’s first planetary defense test mission. Its target is a tiny asteroid known as Dimorphos, a mini-moon that orbits a slightly larger asteroid called Didymos. The 1,376-pound DART probe is going to smash into Dimorphos in an attempt to alter its orbit around its larger counterpart. The purpose of the test is to experiment with kinetic impactor technology as a means of deflecting asteroids that could be headed towards Earth.
NASA keeps a close watch on 28,000 nearby asteroids. Although none of those asteroids currently pose a threat to Earth, we do need a plan in place should a massive space rock be headed towards our planet in the future. Didymos and its tiny companion Dimorphos pose no threat to Earth, and the test won’t cause the system to threaten our planet. The pair is roughly 7 million miles (11 million kilometers) from Earth.
NASA will use ground-based telescopes to monitor Dimorphos’s orbital trajectory after being smacked by the spacecraft, and to also measure the physical effects of the impact itself. At the scene, Europe’s LICIACube will monitor the event with its two onboard cameras, LUKE and LEIA. The Hubble Space Telescope, the Webb Space Telescope, and a camera onboard the Lucy spacecraft, will also attempt to monitor the event.
The European Space Agency (ESA) is planning a follow-up mission to the pair of space rocks; the space agency is scheduled to launch its Hera mission in 2024, which will rendezvous with Didymos by 2026 to study the impact crater left behind by DART, and any other changes made to the asteroid.
For now, DART’s POV will hopefully provide a breathtaking view of Dimorphos as it heads directly into the asteroid. It’ll be a sad end to the spacecraft, but data from the mission could eventually result in the tools needed to deflect a legitimately dangerous asteroid.
Additional reporting by George Dvorsky.
More: NASA’s DART Mission Is Going to Really Mess Up This Tiny Asteroid
Depiction of DART (left) and LICIACube (right). Image: Italian Space Agency
DART won’t survive its mission to deflect an asteroid, but the recently deployed LICIACube—a tiny probe equipped with cameras—will document the encounter in gory detail.
NASA’s Double Asteroid Redirection Test (DART) is the space agency’s first demonstration of a defense strategy to protect against threatening asteroids. The 1,376-pound spacecraft is scheduled to smash into Dimorphos—the junior member of the Didymos binary asteroid system—on September 26 at 7:14 p.m. ET. Dimorphos poses no threat to Earth, but the experiment, should it work, will slightly nudge the moonlet from its current trajectory. In the future, a similar strategy could be used to deflect a genuinely threatening asteroid.
DART will not survive the encounter, but its onboard camera, called DRACO (Didymos Reconnaissance and Asteroid Camera for Optical navigation), will provide a first-person perspective of the collision. Nearby, LICIACube (pronounced LEE-cha-cube) will use its two onboard cameras to document the impact and its aftermath.
DART team engineers inspecting LICIACube before its installation into DART.Photo: NASA/Johns Hopkins APL/Ed Whitman
Controllers issued a command on September 12 for DART to release the 31-pound (14-kilogram) LICIACube, which it had been carrying since its launch on November 24, 2021. A signal confirming the deployment arrived one hour later, much to the delight of Simone Pirrotta, LICIACube project manager for the Italian Space Agency.
“We are so excited for this—the first time an Italian team is operating its national spacecraft in deep space,” he said in a statement. “The whole team is fully involved in the activities, monitoring the satellite status and preparing the approaching phase to the asteroid’s flyby.”
LICIACube, short for Light Italian CubeSat for Imaging Asteroids, was designed and built by Argotec, an Italian aerospace company, with contributions from the National Institute of Astrophysics and the Universities of Bologna and Milan. The tiny probe—built from a 6-unit cubesat bus—is equipped with two optical cameras, named LUKE (LICIACube Unit Key Explorer) and LEIA (LICIACube Explorer Imaging for Asteroid). Together, LUKE and LEIA will collect data to confirm the success of the DART mission and to inform future models of similar tests done with kinetic impactors.
Pirrotta and his colleagues are currently calibrating LICIACube by capturing dynamic images of distant celestial bodies. The tiny probe will receive a series of maneuvering commands just prior to DART’s fatal rendezvous with the 520-foot-wide (160-meter) Dimorphos. NASA’s spacecraft, traveling at speeds reaching 15,000 miles per hour (24,000 kilometers per hour), will be annihilated by the impact. LICIACube will travel past the asteroid roughly three minutes after the encounter to confirm the impact, document the spread of the resulting dust plume, attempt to capture an image of the newly formed crater, and document the opposite side of Dimorphos, which DART will never see.
“We expect to receive the first full-frame images and to process them a couple of days after DART’s impact,” Pirrotta said. We’ll then use them to confirm impact and to add relevant information about the generated plume—the real precious value of our photos.”
By looking at the debris plume and impact crater, scientists hope to gain a better understanding of the asteroid’s structure and surface material. Observations of Dimorphos’s non-impacted hemisphere will improve estimates of the moonlet’s dimensions and volume.
NASA and ESA are planning to document the impact from afar. DART, should it be successful, will alter the speed of Dimorphos in its orbit around the 2,650-foot-wide (780-meter) Didymos “by a fraction of one percent, but this will change the orbital period of the moonlet by several minutes—enough to be observed and measured using telescopes on Earth,” according to NASA. Didymos is roughly 0.75 miles (1.2 km) from its larger companion.
Approximately 28,000 near-Earth asteroids have been documented over the years, with roughly 3,000 discoveries made each year. None of these known asteroids pose a risk to us within the next 100 years, but the chance exists that a threatening asteroid will suddenly come into view. The DART test, should it succeed, could equip us with a valuable strategy for mitigating these existential risks.
Related: NASA’s Upgraded Impact Monitoring System Could Prevent an Asteroid Apocalypse.
In a first-of-its-kind mission, NASA is planning to crash a spacecraft into an asteroid on September 26 (Earth time), and you’ll be able to stream it live.
Humanity’s first experiment in diverting harmful asteroids from our planet, the mission called the Double Asteroid Redirection Test, or DART, is meant to change the asteroid Dimorphos’ orbit by about 1%. Dimorphos is not on a collision course with Earth, but if the 520-foot space-rock were headed towards us, we’d be in bad shape, so NASA is using it as a test case for diverting a hypothetical future killer asteroid.
Where to watch NASA’s asteroid collision
The spacecraft-smashing-into-a-space-rock is happening about seven million miles from Earth, but NASA sent a camera-bearing craft out there to capture all the action. The space agency plans to stream the mission’s climax to the official NASA website,Facebook page, Twitter feed, and YouTube channel.
When will NASA’s craft crash into Dimophos?
The DART mission began nearly a year ago, and the climactic crash landing will happen on September 26 at 7:14 p.m. ET. The live coverage of the event begins at 6 p.m. ET.
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What’s the point of NASA crashing a ship into an asteroid, anyway?
Space rocks hurtle into Earth regularly, but most are burned up in the atmosphere, and most that land are too small to do major damage. But if a large enough asteroid were to hurtle toward us, it would be cataclysmic. The dinosaurs were likely wiped out by an asteroid that hit earth about 66 million years, so NASA is taking the first steps to preventing a similar catastrophe from befalling humans.
“We don’t want to be in a situation where an asteroid is headed toward Earth and then have to be testing this kind of capability. We want to know about both how the spacecraft works and what the reaction will be…before we ever get in a situation like that,” Lindley Johnson, planetary defense officer for NASA, told USA Today in November.
No one is really sure whether the spacecraft’s momentum will be enough to divert the asteroid, but the scientific data NASA gathers might help in future killer-space-rock scenarios (even if it leads to the conclusion that there’s nothing we can do about it.)
How much should we worry about being killed by an asteroid?
Whether we should not worry at all about a space rock hitting earth or worry about it constantly depends on your point-of-view. There are over 27,000 near-Earth objects in our solar system. As far as we know, none of them pose a threat to our planet, but we also know that millions of meteorites bombard Earth every day, although most of them are too small to make it though the atmosphere without burning up. Eventually, our luck is going to run out, though. There’s no telling how long it will be until an extinction-level meteor hits Earth again—it could be in 18 million years, or it could be next month. So go ahead and have an extra piece of cake.
In October 2020, a small spacecraft briefly touched down on an asteroid to snag a piece of it to bring to Earth. Almost two years later, scientists have learned that if the OSIRIS-REx spacecraft had extended its stay even a tiny bit longer, it would have sunk right into the asteroid.
That’s because asteroid Bennu is nothing like scientists had predicted. Rather than being a solid, flying rock, Bennu is actually made up of small, pebble-like particles that are not strongly bound together, creating lots of space on its surface. It’s most comparable to a plastic ball pit, NASA writes in a new release. “Our expectations about the asteroid’s surface were completely wrong” Dante Lauretta, principal investigator of OSIRIS-REx and lead author of a recent paper detailing the findings, said in the release.
OSIRIS-REx arrived at the asteroid in December 2018 with a mission to retrieve a sample from Bennu and carry it to Earth for analysis. The spacecraft touched down on Bennu in October 2020, extending its robotic arm to scoop up a piece of the asteroid. OSIRIS-REx then immediately fired up its thrusters to back away from Bennu. The spacecraft’s sampling head touched Bennu’s surface for approximately 6 seconds before retreating. By stirring up some of the dust and pebbles on the asteroid, OSIRIS-REx was able to grab a couple ounces of material.
OSIRIS-REx Sample Collection at Asteroid Bennu: SamCam View of TAGSAM
The brief rendezvous left quite an impression on Bennu, resulting in a chaotic explosion of pebbles and a crater 26 feet (8 meters) wide. “Every time we tested the sample pickup procedure in the lab, we barely made a divot,” Lauretta said. But after reviewing the footage from the real sample pick-up, the scientists were left confused. “What we saw was a huge wall of debris radiating out from the sample site,” Lauretta said. “We were like, ‘Holy cow!’”
After analyzing the volume of debris seen in before-and-after images of the landing site, the scientists learned that OSIRIS-REx faced as much resistance from touching down on the asteroid as “a person would feel while squeezing the plunger on a French press coffee carafe,” NASA wrote in a statement. That is to say, the spacecraft met very little resistance, certainly not the type of resistance one would expect from landing on a rocky body. As the spacecraft fired its thrusters to depart, it was sinking into the asteroid.
“If Bennu was completely packed, that would imply nearly solid rock, but we found a lot of void space in the surface,” Kevin Walsh, a member of the OSIRIS-REx science team and lead author of a second paper on Bennu’s composition, said in a statement.
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When OSIRIS-REx first arrived at the asteroid, closeup images of Bennu revealed that its surface was filled with boulders, rather than the smooth sandy surface that had been predicted. The images also showed that Bennu was spitting out pebbles into space. “I think we’re still at the beginning of understanding what these bodies are, because they behave in very counterintuitive ways,” Patrick Michel, an OSIRIS-REx scientist, said in the NASA release.
Bennu has been full of surprises. One of the first was its odd shape, similar to a child’s spinning top.