“Asteroid Autumn” Begins Next Month With OSIRIS

In a preview today of the imminent return of samples from the asteroid Bennu, NASA declared the next few months as “Asteroid Autumn.” The OSIRIS-REx spacecraft is just one of three during that time period that will seek to enhance our understanding of asteroids — rocks in space left over from the formation of the Solar System. O-REx as it is fondly called is nearing the end of the first phase of its mission when samples collected from Bennu land in Utah on September 24.

The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer was launched in 2016 and reached Bennu at the end of 2018. After almost two years of reconnaissance, it swooped down to the surface of the asteroid to collect samples in December 2020.

Much to the surprise of scientists, including Principal Investigator Dante Lauretta from the University of Arizona, Bennu was not the solid body they expected, but “it responded more like a fluid” as Lauretta said at a news conference today. They collected more material than expected and will finally get a chance to see exactly how much — and what it’s made of — about a month from now.

O-REx left Bennu in May 2021. It’s taken this long to get back to Earth’s vicinity. The sample return container will detach from the main spacecraft on September 24 and hurtle down through the atmosphere at 27,000 miles per hour. A drogue parachute and then the main parachute will slow it to land at the Air Force’s Utah Test and Training Range at a mere 11 miles per hour according to project manager Rich Burns of NASA’s Goddard Space Flight Center.

Today’s press conference took place from a hangar at the UTTR where NASA and its Air Force partners successfully completed a drop test to practice recovering the capsule.

Maneuvers began on July 26 to put the spacecraft on the correct trajectory to land within a 250 square mile ellipse at the UTTR.

On September 24 at 2:00 am Mountain Time, Burns and partners at Lockheed Martin Space in Littleton, CO, where the spacecraft is controlled, will make a go/no-go decision on whether to separate the capsule from the spacecraft. Burns said they’ll be assessing three factors.

“That decison is based on three criteria. Human safety is our number one priority, as I said. Capsule survivability — the environment as you’ll see is very harsh during the atmospheric reentry. The capsule reenters at 12.3 kilometers per second and heats up very quickly. And then the third is landing accuracy. Can we land in the prescribed area that we know is going to be safe and free of people.” — Rich Burns

If any of those criteria are not met, no command will be sent to separate the capsule from the main spacecraft. They will continue together on their journey through space, around the Sun, and return to Earth’s vicinity in 2 years when another attempt will be made.

The expectation, of course, is that the command will be sent and the capsule will separate at 4:42 am Mountain Time. The main spacecraft will execute a “divert” maneuver 20 minutes later so it does not follow the capsule back to the surface. NASA has other plans for it. Redesignated OSIRIS-APophis Explorer, or OSIRIS-APEX, it will study the asteroid Apophis after it makes a very close pass of Earth in 2029.

The focus for now, though, is the capsule and its belly full of asteroid riches.

Recovery teams will collect the canister, stow it in teflon bags and fly it to Johnson Space Center in Houston, TX where it will be opened and analysis can commence. JSC is home to the Astromaterials Acquisition and Curation Office where samples collected by the Apollo crews and robotic spacecraft are stored and studied.

NASA will share the samples with the Japan Aerospace Exploration Agency (JAXA) and the Canadian Space Agency, who are partners in the project. JAXA was the first to return samples from asteroids with Hayabusa in 2010 and Hayabusa2 in 2020.

But scientists in many other countries also will participate in the analysis of the anticipated 250 grams of material. Lauretta exclaimed O-REx is a “gift to the world.”

“This is a gift to the world. We have laboratories on four continents, 16 time zones, hundreds of researchers, over 60 laboratories that have been getting ready to get this material and we are ready to begin the final science campaign of the OSIRIS-REx prime mission.” — Dante Lauretta

What will they find from these “grandfather rocks” as Lauretta calls them, remnants of the earliest days of the Solar System? Although he estimates that about 10 percent of Bennu by weight is water and they know there’s water in the samples, the chances of biotic material is “vanishingly small.”

“But we do think that there may have been evolution of the organic molecules that could give you insights into the initial stages of the origin of life.” After all, “origin” is the first word in OSIRIS-REx’s name.

Scientists are fascinated by asteroids and O-REx is just one of several asteroid missions in NASA’s current fleet. Two more significant events are coming up just after O-REx returns home, hence the “Asteroid Autumn” moniker.

On October 5, NASA will launch the Psyche mission to an asteroid by that name in the main belt of asteroids between Mars and Jupiter. Psyche is a rather rare asteroid thought to be made mostly of metal.

On November 1, the Lucy spacecraft, launched in 2021, will reach the main belt and make a close approach to one of them as an engineering test of its navigation system. Lucy is on the way to the Trojan asteroids that share Jupiter’s orbit around the Sun.