On Tuesday, March 19th, NASA is going to be hosting a media teleconference regarding the mission of a spacecraft collecting samples of the asteroid Bennu. This is one of the first spacecraft to ever complete such a mission, and is a very big deal in the space science community.
An image taken by OSIRIS-REx of the asteroid Bennu when it arrived in December, 2018.
The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft was launched by NASA on September 8th, 2016, and travelled billions of kilometers from Earth for two years before orbiting the asteroid Bennu on December 31st, 2018. Since it’s arrival, NASA’s probe has been investigating the asteroid and searching for the perfect place for sample collection.
But it does beg the question, why is this mission such a big deal? Why Bennu?
The trip Bennu is one of the most ambitious attempted by a probe, as it will end up being a years-long endeavor. December marked the beginning of the two years that OSIRIS-REx will be investigating Bennu’s surface. It will brieftly touch the surface of Bennu around July of 2020 to collect between 60 and 2,000 grams of dirt and rocks (the largest sample gathered from a space object since the Apollo moon landings). After packing the sample into a capsule, OSIRIS-REx will begin the journey back to Earth and land in a Utah desert in 2023. Due to this, the mission is very important as observations of Bennu indicate that it could provide information on the formation of the solar system and the universe.
But Bennu is not only chosen because it is a leftover fragment of the tumultuous formation of our solar system. Yes, it is very old. The mineral fragments within this asteroid could be even older than our solar system, comprised of the dust of dying stars flung across space 4.6 billion years ago that eventually coalesced into everything we know today. However, it is also much closer than most asteroids. Most are between Mars and Jupiter, in the solar system’s asteroid belt. Bennu orbits between Earth and Mars on the same orbital plane, and comes closest to Earth every 6 years. In addition, this asteroid is the perfect size. It’s diameter is a little larger than the Empire State Building, which makes the asteroid approachable by probes and rich in regolith (unconsolidated rocky material covering bedrock, aka what NASA wants to collect parts of).
Bennu is also incredibly well preserved due to the vacuum of space, and may contain explanations to the origin of life on Earth. Scientists have been studying Bennu since it was discovered in 1999, and know that it is primarily carbon-constructed, so it could contain some clues into the eternal question of how life began on Earth since it has easily been around since then. Astronomers classify asteroids into one of three categories, with the most primitive being the carbon-rich ones that have most likely not changed in 4 billion years (like Bennu). Scientists are also interested in Bennu because it has a shifting orbit, and it is likely that it will collide with Earth in the late 22nd century.
Overall, monitoring the mission of OSIRIS-REx will be interesting over the next few years. Already the probe found hydrated minerals on the asteroid’s surface, indicating the presence of ancient water on the rocky surface of this space traveler. While we will not find out everything OSIRIS-REx discovers until September of 2023, it is definitely something to look forward to.
Sources:
https://www.nasa.gov/press-release/nasa-to-host-media-teleconference-on-asteroid-sample-return-mission
https://solarsystem.nasa.gov/news/517/why-bennu-10-reasons/
https://www.asteroidmission.org/why-bennu/