A NASA led effort to land a spacecraft on an asteroid, gather rock samples, and return them to Earth has overcome its first hurdle by making an historic touchdown on Bennu, an asteroid that is around 200 million miles away.
Launched from Cape Canaveral in September 2016, the so-called Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) probe has been orbiting the asteroid since December 2018.
NASA scientists are hoping that during its brief landing on the surface of the asteroid, which took place on 20th October 2020, the spacecraft was able to gather material that could help advance our understanding of the early solar system.
Hailing the achievement NASA Administrator Jim Bridenstine said: “This amazing first for NASA demonstrates how an incredible team from across the country came together and persevered through incredible challenges to expand the boundaries of knowledge. Our industry, academic, and international partners have made it possible to hold a piece of the most ancient solar system in our hands.”
During the manoeuvre the spacecraft fired its thrusters to nudge itself out of orbit around Bennu before extending the shoulder, then elbow, then wrist of its 11-foot (3.35-metre) sampling arm, known as the Touch-And-Go Sample Acquisition Mechanism (TAGSAM).
After a four-hour descent, at an altitude of approximately 410 feet (125 metres), the spacecraft executed a so-called “checkpoint” burn, the first of two manoeuvres to allow it to precisely target the sample collection site, known as “Nightingale.”
Ten minutes later, the spacecraft fired its thrusters for a second “Matchpoint” burn to slow its descent and match the asteroid’s rotation at the time of contact.
It then continued a treacherous, 11-minute coast past a boulder the size of a two-story building, nicknamed “Mount Doom,” to touch down in a clear spot in a crater on Bennu’s northern hemisphere.
Real-time data indicates the TAGSAM successfully contacted the surface and fired a burst of nitrogen gas that should have stirred up dust and pebbles on Bennu’s surface, some of which should have been captured in the TAGSAM sample collection head.
It will take about a week for the OSIRIS-REx team to confirm how much sample the spacecraft collected. If Tuesday’s sample collection event, known as “Touch-And-Go” (TAG), provided enough of a sample, mission teams will command the spacecraft to begin stowing the primordial cargo to begin its journey back to Earth in March 2021. Otherwise, they will prepare for another attempt in January.
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To store the sample, engineers will command the robotic arm to place the sample collector head into the Sample Return Capsule (SRC), located in the body of the spacecraft. The sample arm will then retract to the side of the spacecraft for the final time, the SRC will close, and the spacecraft will prepare for its departure from Bennu in March 2021 — this is the next time Bennu will be properly aligned with Earth for the most fuel-efficient return flight.
The spacecraft is scheduled to return to Earth September 24, 2023, when it will parachute the SRC into Utah’s west desert where scientists will be waiting to collect it.
A wonderful achievement NASA.
Completely fascinating, although I try to keep up with the news around space exploration, its sad to say that I was unaware of this project. Just a great achievement, keep up the great work NASA!
I’m glad they’re not attempting to bring the whole asteroid back !
Without wishing to diminish this achievement, what’s ‘historic’ about it? The two Japanese Hayabusa probes have both collected samples from asteroids, and Hayabusa-1 returned its (very small) sample earth in 2010. Hayabusa-2 is due to return in December.
I heard this reported – rather oddly – on the BBC Radio 4 Today program this morning. The asteroid was described as being ‘taller than the Empire State building’ which left me wondering about concepts of ‘tallness’ or ‘up-ness’ in space. Oh well, I thought, they probably mean the same size and shape – but no, asteroid Bennu looks more like a lemon …
They then talked about sucking up the sample – presumably by using an even stronger vacuum than is normally found out in space … ?
When done to the NASA team – there is still plenty of work to do for the advancement of science knowledge more generally
What’s ‘historic’ about it is that it’s the first American mission. The Japanese mission wasn’t, so it obviously wasn’t historic – from NASA’s point of view.
Well done NASA and partners, and boo to the decriers. Of course it’s historic, even if the Japanese have already done something similar. Where are the results from the 2010 return samples? It would be nice to see and compare when the OSIRIS Rex probe returns.
I had a question about how OSIRIS-Rx maintained its orbit, given that Bennu has microgravity. i NASA was kind enough to answer. The response came from Nancy Neal Jones Senior Communications Manager, Solar System Exploration Division, NASA’s Goddard Space Flight Center. She consulted the mission’s flight dynamics manager, whoprovided the following information.
For most of our orbital phases, we design the orbit in such a way that Bennu’s gravity, solar radiation pressure, and gravitational acceleration from the Sun balance out. The resulting “frozen” orbits, as their called, are typically stable for long periods of time. We always had “placeholders” in the schedule for small trim maneuvers in orbit just in case, but rarely had to use them on the mission. When we do need to make small tweaks, or to initiate survey flybys and reconnaissance passes, we use the spacecraft’s hydrazine thrusters. Maneuvers on the order of 10 cm/s are all that is needed to make substantial changes to the orbit.
That, I thought, was both interesting and instructive. I had one more question but didn’t ask: How is OSIRIS-Rx coming home? It took two years to get to Bennu, but it’s taking three years to return. I imagine it has something to do with getting gravity assists from planets, but I’m curious to know if that’s true and what the path will be. Anyone know?