When NASA’s DART spacecraft crashes into asteroid Dimorphos on September 26, it will have a silent witness: an Italian cubesat called LICIACube will observe the groundbreaking experiment in real time for keen scientists on Earth.
LICIACubeor the Light Italian Cubesat for Imaging of Asteroids, is a 31-pound (14-kilogram) micro-satellite that hitched a ride on DART (the double asteroid redirect test) to the Didymos-Dimorphos binary asteroid system. DART deployed the cubesat on Sunday (September 11) at 7:14 p.m. EDT (2314 GMT) to give LICIACube 15 days to take a safe position to observe DART’s collision with Dimorphos. Impact is a first-of-its-kind experiment to alter the orbit of a space rock in a crucial test of a planetary defense concept that could one day save the lives of millions of people on Earth.
“LICIACube will be released from the dispenser on one of the external DART panels and will be guided (braking and rotating) to begin its autonomous journey to Dimorphos,” said Elena Mazzotta Epifani, astronomer at the Italian National Institute of Astrophysics (INAF). ) and co-investigator of the LICIACube mission, Space.com told Space.com in an email. “The cubesat will point its cameras at the asteroid system, but also at DART, and will probably take some pictures of it.”
Related: NASA’s DART asteroid impact mission explained in pictures
The only first-hand witness
LICIACube, equipped with two optical cameras, will follow DART toward Dimorphos and eventually settle in to watch the drama from a safe distance of 600 miles (1,000 kilometers) as the 1,345-pound (610 kg) spacecraft hits the rock on September 26, Added Mazzotta Epifani. “The impact of the DART will be [seen] as an increase in target brightness when comparing images of Dimorphos taken before and after impact,” she wrote.
At the time of impact, Dimorphos and Didymos will be approximately 6.8 million miles (11 million km) from Earth, according to NASA (opens in a new tab). Although terrestrial astronomers cannot see the impact, they will observe the system closely in the coming weeks to determine if the 12-hour orbit of the 560-foot-wide (170-meter) Dimorphos around the 2,600-foot wide (800 m) Didymos will have accelerated as planned. They will do this by measuring the intervals between periods of brief attenuation that occur when the two asteroids slip away.
But while such observations might be enough to confirm that the experiment worked, they would not provide any details about the effects of the DART impact on the asteroid. And so, right after DART hits Dimorphos, LICIACube will come closer to inspect the scene.
“LICIACube will perform… a “fast flyby” approximately 3 minutes after DART impact at a minimum distance of approximately 55 km [34 miles] from the surface of Dimorphos to its closest approach,” Mazzotta Epifani wrote. “Image acquisition by the two onboard cameras will be nearly continuous for approximately 10 minutes and will be dedicated to the impact and non-impact sides targets, as well as the plume produced by the DART impact.”
LICIACube will then send the images to Earthbut Mazzotta Epifani warned it could take weeks to get all the data.
Nothing is known about Dimorphos
Understanding the effects of the DART impact on Dimorphos at depth is crucial because a similar system may one day be needed to deflect a rock on a collision course with Earth. An asteroid the size of Dimorphos could cause continent-wide destruction while the impact of an asteroid the size of the larger Didymos could be felt worldwide.
But there’s a catch: Although astronomers know in detail the orbits of most of the 26,115 currently known near-Earth asteroids (2,000 of which are classified as “potentially hazardous” due to their size and closest approach to Earth), they know surprisingly little about these rocks. In particular, scientists do not understand the density of the material the rocks are made of and can only guess how the surface might behave during an impact.
The team behind NASA’s OSIRIS-REx missionwho landed near Earth Bennu asteroid in October 2020, experienced firsthand the pitfalls of these unknowns. The asteroid’s surprisingly smooth surface nearly engulfed the spacecraft, with the landing generating what OSIRIS-REx principal investigator Dante Lauretta described as “a huge wall of debris” which could easily have destroyed the spacecraft.
Lauretta, a planetary scientist at the University of Arizona, says Space.com when the incident was announced, he suggested that a deflection attempt might be more difficult than expected, as the soft-surfaced asteroids might simply absorb the impact.
The team behind DART knows as little about Dimorphos as the OSIRIS-REx team knew about Bennu before the spacecraft arrived on the asteroid. Images captured by DART itself before impact and then by LICIACube will be the first detailed views of Dimorphos astronomers will ever see.
“We know the general surface properties of the larger Didymos, from ground-based spectroscopic and photometric measurements, but we know next to nothing about Dimorphos, which is too small to produce an effect distinct from that coming from the main body,” said writes Mazzotta Epifani. “We *assume* from theoretical models of binary asteroid formation that Dimorphos is very similar to Didymos, but we know next to nothing about the degree of cohesion of surface materials, the size distribution of debris from surfaces, etc.”
Scientists believe Dimorphos is a so-called ‘rubble-pile asteroid’ like Bennu: a conglomeration of rocks and earth that broke off in the past from the main asteroid Didymos and is now only held together by the strength of gravity. As the asteroid is rather small, this force is quite weak. Because of this, astronomers don’t understand the impact DART will have, the amount of material it will blast into space, and the size of a crater it might leave behind.
Lessons for the future
“Together, DART and LICIACube will analyze for the first time and in great detail the physical properties of a near-Earth binary asteroid, allowing us to study its nature and have clues about its formation and evolution,” wrote Mazzotta Epifani. “LICIACube will obtain multiple images of the ejecta plume produced by the impact itself, from the DART impact [crater] size, as well as the non-impacting hemisphere to help us study the size and morphology of the crater and the effects on surface properties in the surrounding area.”
The good news is that the more information scientists gather, the better they will be able to predict the effects of possible future interventions on similar asteroids.
The Italian Space Agency, which oversees the LICIACube mission, is currently evaluating mission expansion plans to conduct further studies of the Didymos-Dimorphos binary asteroid system, Mazzotta Epifani wrote, adding that any decision to extend the mission beyond the immediate consequences of the impact will be made only after September 26th.
First Italian deep space mission
For the Italians, who have a booming space industry that has contributed to some of Europe’s most high-profile space projects (including the European Columbus module of the International Space Station), LICIACube is the first deep-space mission on which the country will operate. her own. Developed and built in less than three and a half years, LICIACube is similar to ArgoMoon, one of cubesats hitchhiking on the moon about NASA Mission Artemis 1who is still Awaiting takeoff after a fuel leak halted a launch attempt on September 3.
“LICIACube is not only the first deep space mission that Italy will operate, it is also the first fully designed, built and managed in Italy, including data reception and management,” Mazzotta wrote. Epifani.
With LICIACube, Italy has stepped in to fill the void created by the delays in approving the budget of the European Space Agency (ESA) HERA missiona much larger spacecraft, which was originally scheduled to arrive on the Didymos-Dimorphos duo before the DART impact to inspect the system and then observe the crash and study its aftermath in detail. ESA still plans to launch HERAbut the spacecraft will not reach Didymos until 2027.
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