Published: 2020-10-19 21:23:00
Updated: 2020-10-19 21:47:55
Posted October 19, 2020 9:23 p.m. EDT
Updated October 19, 2020 9:47 p.m. EDT
Launched in 2018, the OIRIS-REx mission reached its target, asteroid Bennu last December and has been mapping its target since December 2019. Initial plans to use laser targeting to guide landing were scrapped when the surface was found to be cluttered with a "rubble pile" of varying shapes and sizes of rocks.
On Tuesday, December 20 shortly after 5 p.m. EDT, OIRIS-REx will begin its descent down its cameras to the surface to grab a piece of the asteroid, on its own. NASA TV coverage begins at 1 p.m. with discussion from mission scientists and engineers.
OIRIS-REx's 11-foot Touch-and-Go Sample Acquisition Mechanism (TAGSAM) will make contact with the surface, eject pressurized nitrogen, and collect up at least 2-ounces of dust and rock. Even at the speed of light, ground controllers wont know until 18 minutes later if the first attempt was successful. The trip to return the samples to Earth will require three years.
Previously known as Asteroid 1999 RQ36, Bennu was renamed by then nine-year-old Mike Puzio of Greensboro who won the international student contest. He imagined the TAGSAM arm and solar panels on OSIRIS-REx look like the neck and wings of Bennu, which Egyptians often depicted as a gray heron.
The name Bennu struck a chord with the selection team which included the mission’s principal investigator Dante Lauretta. Bennu is associated with creation and rebirth in Ancient Egyptian mythology, representing the first life to appear.
The 15-passenger van sized OSIRIS-Rex stands for for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer.
Asteroids like Bennu are the left overs from the formation of the Solar System which offer scientists clues which have been wiped away from the Earth or its moon.
Bennu is carbon-rich, a key element necessary for life. This Solar System left over has also not changed much in 4.5 billion years, making it a geologic and chemical time machine of sorts.
“Organic carbon is interesting because we think asteroids like Bennu could have delivered organic matter to early Earth,” Hannah Kaplan of NASA’s Goddard Space Flight Center told Scientific American last week.
Bennu is in the Goldilocks zone for the mission, not too close to the Sun to make heating a problem, and far enough from the Sun to be too cold or too difficult to generate power, juuuuust right. Plus its slow rotation, about once every four hours, makes that touch and go a lot less risky.
Bennu also has a very slim 1 in 2,700 chance of colliding with Earth late in the 22nd century. Scientists are also eager to learn as much as possible about its orbit and rotation to help better understand other potentially hazardous asteroids.