After five years in space including 2.5 years for observing and collecting the samples of the asteroid, at last NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft is coming back to Earth carrying a generous amount of dust and rocks. The spacecraft arrived at Bennu, an asteroid near Earth, in 2018. After spending enough time, it bids the farewell on Monday, May 10, at 4:23 pm EDT. The team following this project is excited about investigating the samples but also a little bittersweet about bidding farewell to the asteroid after spending so much time exploring it.
About the mission
OSIRIS-REx was launched on September 8, 2016, at 7:05 pm EDT, as pre-planned it will reach the Bennu (formerly 1999 RQ36) in 2018. The mission is to get a 2.1-ounce sample back to earth for research, it will help scientists to investigate how planets formed, how life began and also improve the understanding of asteroids that could impact the earth.
At 4:16 pm ET, the team received the signal from the spacecraft that it had fired thrusters and was going to separate itself from the established orbit around Bennu. The spacecraft throttled its engine for seven minutes and as a result, it thrusts away from the asteroid at 600 miles per hour (approx. 1000 km per hour). Its primary mission is completed and now it will put its trajectory to circle the earth inside Venus’ orbit.
After revolutionizing the sun twice, it will reach the earth on September 24, 2023, and drop the sample at Utah Test and Training Range. A dozen engineers were writing the codes to instruct the spacecraft when to leave the surface. Now, how to get the sample back on earth is their next motive. Mike Moreau, OSIRIS-REx deputy project Manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said, “Our whole mindset has been, ‘Where are we in space relative to Bennu?’. Now our mindset has shifted to ‘Where is the spacecraft in relation to Earth?’”
For the entry of the capsule carrying the sample in Earth’s atmosphere, the location and angle should be precise. The team would prepare for it a few weeks prior. However, if it comes in too low, the capsule will bounce back from the atmosphere, if it is too high, the capsule will burn from the friction and heat of the atmosphere. Unfortunately, if the spacecraft cannot release the capsule, the team has a backup plan and can bounce it back and retrieve it in 2025.
Accomplishments and Surprises
- On December 31, 2018, the team realized that Bennu was releasing small rocks into space. Mike Moreau said, “We had to scramble to verify that the small particles being ejected from the surface did not present a hazard to the spacecraft.”
- The scientists predicted that its surface would be smooth but in reality, its surface was littering with boulders. As a result, scientists had to quickly develop an accurate navigation system for smaller-than-expected sites.
- There was also a finding that confirmed that minerals on the asteroid would be rich in carbon and even show some traces of ancient water.
Heather Enos, an OSIRIS-REx deputy principal investigator, said “This mission emphasizes why we have to do science and exploration in multiple ways – both from Earth and from up-close in space – because assumptions and models are just that.”
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