EPISODE 113: OSIRIS-REX SAMPLE RETURN PREPARATION

Transcript

Ron Mink: Ultimately, the science community is going to receive the means to help unlock the secrets of the solar system within their own labs here on Earth.

Our spacecraft was designed to fly very precisely at Asteroid Bennu to take all of the incredible observations of the surface of Bennu and identify a sample site and ultimately collect the sample from the surface. The team performed phenomenally at Bennu and so did the spacecraft.

We’re very confident that the capsule will perform as expected and slow down to a nice gentle landing in September.

Deana Nunley (Host): Welcome to Small Steps, Giant Leaps, a NASA APPEL Knowledge Services podcast where we tap into project experiences to share best practices, lessons learned and novel ideas.

I’m Deana Nunley.

The first U.S. mission to collect a sample from an asteroid will return to Earth on September 24. NASA’s OSIRIS-REx spacecraft has been cruising through space since it departed asteroid Bennu in May 2021 with an estimated half-pound of pristine asteroid material aboard.

OSIRIS-REx Mission Systems Engineer Ron Mink is here to discuss preparations for the sample return. Ron, thank you for joining us.

Mink: Thank you for giving me the opportunity to share the excitement of OSIRIS-REx with the Small Steps, Giant Leaps listening audience.

Host: Absolutely. What can we expect on September 24?

Mink: Well, we can expect the successful conclusion of the United States’ first asteroid sample return mission. And that starts with the spacecraft releasing the sample return capsule with the sample from asteroid Bennu at about 4:42 a.m. Mountain Time, and that’s in Utah time, where the capsule will be landing. And we know that very precisely, that’s why I’m so precise on the numbers. And about four hours later, the capsule will enter the Earth’s atmosphere over the coast of California and after slowing down significantly from friction with the atmosphere and a small drogue parachute about 10 minutes before 9 a.m. the recovery personnel from NASA and the Department of Defense at the Utah Test and Training Range, and the NASA Live audience should see the main chute unfold, and guide the capsule to a soft landing about five minutes before 9 a.m., again Mountain Time.

And following landing two recovery helicopters with recovery personnel from both NASA and the Department of the Defense will approach the capsule and load the capsule into a handling fixture and then onto a sling so that it will be carried by one of the two helicopters back to the DOD facility, which houses a temporary clean room. Once in the clean room, the clamshell return capsule will be opened, and the sample canister will be placed under a nitrogen gas purge to keep the sample pristine. And then the canister will be removed and prepared for transport to the Johnson Space Center a couple of days later.

Host: What’s the status of preparations for the sample return?

Mink: Well, both the flight teams, which includes the spacecraft operators at Lockheed Martin in Denver, Colorado, and the mission management team from Goddard and the recovery teams, which includes government team members and our partners at the Utah Test and Training Range. They’re finalizing their procedures and testing command sequences to ensure that the spacecraft operates as expected and recovery procedures will support a rapid recovery of the sample.

So, we’ve completed two operational readiness tests in the last couple of months, which tests the flight team to go through procedures and command sequences to release the sample return capsule and divert the spacecraft so that the spacecraft doesn’t reenter the atmosphere to support an extended mission. And then we have a third and final dress rehearsal planned for the end of August, which will include all elements of the project from the flight team releasing the capsule and a test capsule being dropped from a helicopter at the Utah Test and Training Range and recovered by the field team at the Utah Test and Training Range.

Also, this week the team is planning to conduct our second of three walk-in maneuvers, placing the spacecraft on the trajectory to fly by the Earth at an altitude of about 125 miles. And then the third walk-in maneuver will occur on September 10, which will actually target the spacecraft and the return capsule to Earth entry.

Host: What do you think are the most interesting aspects of the work the team is doing to prepare to retrieve the sample?

Mink: Well, I think the most interesting aspects are when all elements of the project have to come together for these operational readiness tests that I mentioned, because it involves the diverse teams working in Denver and working in Utah and at the Goddard Space Flight Center to put all of our procedures and processes into place to ensure that we’re ready for the actual events. And it forces all of the elements of the project to work on a timeline to release the capsule, divert the spacecraft from hitting the Earth, and also recovering the capsule.

We recently completed in June what we call an off-nominal Operational Readiness Test, or ORT, that included many things that were planned to go wrong with the intention of stressing the team and identifying needed improvements in processes and procedures. So, preparing for that test, our test director put together what he calls a gremlin team to come up with things that would go wrong to make the job more difficult for the team. And some of those things that went wrong included key personnel, key operators, or managers would suddenly be unavailable due to illness or some other factor and their backups had to step in. In one case the communications from the main mission operations building at Lockheed Martin were completely cut off, so we had to rely on our cell phones and hotspots for communication. And of course, the test director ensured that the spacecraft misbehaved multiple times and the team had to recover from those problems. So, it really stressed the team, but it was a great exercise to bring the team together to exercise backup personnel to ensure that whatever nature and the mission throw at us in September, we’ll be prepared for.

Host: What were or are the biggest engineering challenges?

Mink: Well, I think I’ll discuss two aspects of the Earth return here. And so first of all, the sample return capsule has to be targeted to enter the Earth’s atmosphere in a very narrow corridor, actually less than half a degree wide, to ensure that the capsule survives the extreme reentry environment. So, the spacecraft in the days leading up to entry have to maneuver and point the spacecraft very precisely. And that has been a challenge on previous sample return missions. However, our spacecraft was designed to fly very precisely at Asteroid Bennu to take all of the incredible observations of the surface of Bennu and identify a sample site and ultimately collect the sample from the surface. All of those required precision navigation and maneuvering by the spacecraft. And so, having that experience under our belts, the team performed phenomenally at Bennu and so did the spacecraft. And so based on that performance, we will have no problem targeting that very narrow entry corridor.

The other big engineering challenge for very much all reentry missions is that the capsule has to slow down from 27,000 miles per hour when it enters the Earth’s atmosphere down to zero in a span of about 13 minutes. And so, the OSIRIS-REx capsule is designed very much like the Stardust capsule that successfully entered the atmosphere over 17 years ago. The outer shape of the capsule, what’s called the aeroshell, which consists of the heat shield that is on the front of the capsule as it enters and then the back shell, are the same as the Stardust mission. And so we’re very confident that the capsule will perform as expected and slow down to a nice gentle landing in September.

Host: What’s next for the sample after the capsule lands in the Utah desert?

Mink: Well, once the sample canister is removed from the capsule, it will be transported to the dedicated curation facility at the Johnson Space Center where the capsule will be opened to reveal the sample collector, which is also called the Touch-and-Go Sample Acquisition Mechanism, or TAGSAM. And once in the safe and very, very clean confines of the curation facility, the TAGSAM will be opened to remove the sample of asteroid Bennu and it will be weighed to verify, first of all, that the requirement for at least 60 grams of collected sample is met. We expect it to be well over 250 grams, but we’ll measure the sample, and then the sample will be divided up for scientific study by the OSIRIS-REx team. And also a significant portion of the sample will be dedicated to study by future scientists through future NASA programs that can use new tools and techniques to analyze the sample that haven’t even been thought of yet.

Host: Could you talk about OSIRIS-REx from a systems engineering perspective and what’s been involved in making the mission a success?

Mink: Sure. One of the key systems engineering practices that we used, starting with the proposal for OSIRIS-REx to be the third New Frontiers’ mission way back in 2008, we developed what we call the Design Reference Mission, which is used across NASA for both planetary and Earth science and human missions. But with a Design Reference Mission we divide the mission into discrete phases, each phase with its own objectives. And once that Design Reference Mission is defined and we start to develop the spacecraft in the operations concept, we assign a phase lead, a systems engineer phase lead, to each of these mission phases to ensure that the requirements on the spacecraft, how the spacecraft is designed, how the spacecraft and ground system are validated and verified, and how the operations concept and operations plans come together to ensure the success of each phase in meeting its objectives. So that ensures that the system as a whole, once we’re ready to launch, has been designed to support the objectives for all of the discrete mission phases.

And this was an excellent systems engineering approach for OSIRIS-REx, in particular for the asteroid rendezvous and sample collection portion of the mission. We, both Lockheed Martin, our prime contractor, and Goddard, assigned phase leads for each portion of the mission. And those two phase leads basically worked together to ensure that not only was the system designed to execute the Bennu operations, but that continued during operations to ensure the mission was executed as planned.

So, I personally served as the science phase lead for all of the science observation campaigns conducted at Asteroid Bennu to map the entire surface of the asteroid, to collect critical information about the surface, to ultimately navigate down to the surface and conduct the sample collection. And also, currently I’m serving as the Earth Return Phase Lead. So it’s very different aspects of the mission that are required for sample return versus Bennu operations, but this entire approach allowed me and our other phase leads to ensure that the objectives throughout the mission were fully met.

Host: I understand you’ve been working on this mission for over 15 years. What are your thoughts and feelings with this enormous milestone just a couple of months away?

Mink: It’s rather bittersweet for me. I mean, it’s been quite an investment of my time and the time and effort of hundreds of people mostly in the United States, but even from around the world. We had contributions from the Canadian Space Agency and science contributions from around the world. So it’s a culmination of an enormous amount of hard work by a large number of people, but ultimately the science community is going to receive the means to help unlock the secrets of the solar system within their own labs here on Earth.

In another sense, it’ll be bittersweet because over such a long mission and a long commitment, unfortunately not everyone makes it to the end. And recently, just earlier this month, a dear friend and colleague that I worked with on OSIRIS-REx for six years, Jonathan Gal-Edd passed away. And so that was heartbreaking that he would not be able to witness the culmination of this amazing mission.

One thing I also want to mention regarding kind of my thoughts and feelings is that devoting so much of my time at Goddard to one mission is a bit like raising a child, which I have experience with this as well. In fact, my youngest son was just eight months old when I started working on the OSIRIS-REx proposal back in 2008. And when the capsule lands, he’ll be starting his sophomore year in high school. So, in both senses, getting to this point is an incredible sense of accomplishment, but you wonder how the time could have gone so fast.

Host: Well, Ron, this has been very interesting and thank you so much for sharing your personal reflections and the impact that it has and the timeline along with things that are going on in your life. We do express our condolences to you, sympathy to all of the team in the loss of your dear colleague.

Mink: Thank you.

Host: But thank you so much for being with us today. I’ve really enjoyed getting to talk with you.

Mink: That’s great. I really appreciate the opportunity and look forward to the excitement coming in September.

Host: Absolutely. Do you have any closing thoughts?

Mink: Just wake up Sunday morning and watch the landing on NASA Live.

Host: Ron’s bio and links to related resources are available on our website at APPEL.NASA.gov/podcast along with a show transcript.

If you’d like to hear more about what’s happening at NASA, we encourage you to check out other NASA podcasts at nasa.gov/podcasts.

As always, thanks for listening to Small Steps, Giant Leaps.