OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is the first NASA asteroid sample collection mission. It had just done a touch-and-go maneuver on 20 Oct 2020, and successfully collected a sample of Bennu!
OSIRIS-REx’s trajectory
The OSIRIS-REx spacecraft is on a 7-year mission to explore the asteroid 101955 Bennu. It became airborne in Sep 8 2016, and started its 2-year journey to the asteroid. It’s target is to collect a sample weighing at least 59.5 grams. The probe arrived at Bennu and the team decided to collect its first sample on Nightingale on Oct 20 2020. So, how did it accomplish that feat? But, let’s go deeper.
The spacecraft is on the first NASA mission to collect a piece of an asteroid, but Japan had done it twice in the Hayabusa series. It is the third of NASA’s New Frontiers program. In fact, the probe was launched in the famous Atlas V rocket, which is the start of many planetary missions.
On its way to Bennu, it performed 2 DSMs (Deep Space Maneuvers), in order to edit is trajectory to head back to Earth. The Earth flyby was as close as 17,200 kilometers, aiming its course to the NEO. After a 2-year journey, it arrived at Bennu on Dec 3, 2018, and collected its first sample just recently.
Then, once the sample is safe, the spacecraft will wait for its opportunity to go back to Earth in March 2021. After a 2-year journey once again, its capsule will be on a desert in Utah in Sep 24 2023, and scientists can collect the sample from the probe and analyze it in top laboratories.
How the spacecraft collected a sample?
Okay. I’ll talk about how to collect an asteroid sample. If you blow on sand, it will disperse to different places. That’s similar to how OSIRIS-REx’s sample collection arm works. The probe released a powerful burst of nitrogen, making rocks of Bennu fly everywhere. Some of them went inside the arm and are stored in the spacecraft afterward. Then, 6 seconds later, the robotic arm left the ground, and the TAG (Touch-and-Go) was complete, kind of like an aircraft going-around after landing on the runway.
But, getting the right amount of samples is very difficult, because you need to calculate how much force it takes to store more than 60 grams of precious rocks. This is because they need to know whether the materials are as hard as steel, or as soft as sand. But, if the TAG made a lot of mess, it has likely collected more samples than desired.
So, what if the probe didn’t take a sample on the rest of the journey? Well, in that case, the spacecraft will TAG once again on Jan 12 2020 on Osprey.
So, we hope OSIRIS-REx to collect a passed sample that can be brought to Earth one day!
Credits
- “OSIRIS-REx”, NASA Solar System Exploration, https://solarsystem.nasa.gov/missions/osiris-rex/in-depth
- “NASA’s OSIRIS-REx Spacecraft Successfully Touches Asteroid”, NASA, https://www.nasa.gov/press-release/nasa-s-osiris-rex-spacecraft-successfully-touches-asteroid