EPISODE 101: ARTEMIS MISSIONS

Transcript

Mike Sarafin: The system performed as designed or in many cases better than we had predicted.

When you start thinking about the system that we’re flying here, the Orion spacecraft, and the fact that we essentially established our entry target line and performed our de-orbit maneuver from a quarter million miles away when we did the return, powered fly-by by the Moon, that is remarkable precision.

We have a series of increasingly complex missions ahead of us. On Artemis II, we are going to have our first crewed flight test.

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.

Artemis I was the first integrated test of NASA’s deep space exploration systems. Launched November 16, 2022, the 25-day, 1.4-million-mile, uncrewed flight test was a major step forward as NASA and its commercial and international partners work to establish a sustainable presence on the Moon to prepare for missions to Mars.

Mike Sarafin is the Artemis Mission Manager and joins us now. Mike, thank you for being our guest on the podcast.

Sarafin: All right, thanks for having me, Deana.

Host: As you reflect on the enormously successful Artemis I mission, what excites you most about it?

Sarafin: Well, the uncrewed flight test that we conducted in late 2022 told us that we are absolutely on the right path for our Moon to Mars Program and that we have a foundational human deep space transportation system. So that is the Space Launch System rocket, capable of delivering large cargo and crew elements to the point of trans-lunar injection, the Orion spacecraft, which is capable of sending humans to the Moon and then returning them back to Earth through the use of an ablative heat shield. And then our ground systems that we use to fuel and process and test and stack and launch the Space Launch System and the Orion spacecraft. But also, that we have all the right tooling, test facilities, and production capabilities in place as well as the infrastructure here on the ground. Things like the Deep Space Network, the Launch Control Center, the Mission Control Center, and then our recovery assets. So, we’ve got all the foundational elements here and we are absolutely on the right path for our Moon to Mars Program.

Host: Let’s delve into your responsibilities as Mission Manager on the first Artemis mission. What all had to come together to make this a success?

Sarafin: Well, there were probably 10,000 things that had to come together in order to do that, but fundamentally where my role starts is, what are we doing? And why are we doing it? And setting up for the initial flight test, one of the things that we focused on very early on was, what are our mission priorities? And how do all the objectives fit into these categories of priorities in the event that we find ourselves short on time, short on propellant, short on performance? And we use the mission priorities to align the teams and focus the work. Whether it was planning the normal mission or whether it was planning aborts or early return scenarios or alternate missions. And those mission priorities manifested themselves in so many ways in terms of the mission design, and the analysis that needed to be conducted for power and for thermal and for propulsive elements throughout the course of the mission planning. It manifested itself in terms of the launch commit criteria and the flight rules and the recovery decision criteria.

It manifested itself in terms of contingency planning and mission procedures as well as just our decision gates. And there were a lot of different things that kind of hinged off those mission priorities. And we had to understand what we were trying to accomplish and the capabilities that were in place. So, the spacecraft and the rocket inherently have capabilities, but they also have limitations, design limits and design specifications. So, we had to really dig down and understand what those capability constraints were as much as the limits. And then we also had to constrain the work because we just couldn’t analyze an infinite number of cases. So, we had to establish based on the priorities that we all agreed to, we had to establish what is the analysis case set and what is the relative priority of that work such that we could make the best use of people’s time and our limited resources to get the mission planned.

So fundamentally, that’s what my role was as a Mission Manager. And then when it came time to execute the mission, we had all these plans and procedures in place. And if we were off the script, it came back to me because I was there during the planning process and understood fundamentally what was baked into the mission. Whether we had done the work or not, and whether it was in the scope of the plans that we had on the shelf, if it wasn’t part of the normal mission plan. So that’s what we had to do in order to get here. And thankfully, we stayed largely along the normal mission plan, which makes my job relatively easy in-flight if we stay along the planned mission and don’t have to delve into an alternate mission or some other scenario.

Host: What were the toughest challenges you and the team had to overcome?

Sarafin: Yeah, we had a number of challenges just to get off the pad. We had to deal with hydrogen leaks on both our eight-inch quick disconnect, which is used to fill and drain the core stage, as well as the four-inch quick disconnect, which is used to establish something called the hydrogen bleed, which is used to thermally condition the core stage RS-25 engines.

And then we had a sensor issue on the engine bleed system, and we were unable during our initial launch attempt to confirm that we were within the start box for the engines. And we had to scrub and come back and reassess what the hardware was telling us. And it turned out it was a sensor problem and not an actual engine or a core stage problem.

And then weather. Weather was a chronic problem throughout the course of the Artemis I mission. If we go back to the wet dress rehearsals and in some of the testing that we did on the pad out at the Kennedy Space Center. But then also just prior to our initial set of launch attempts in late August, early September, we had multiple lightning strikes in the vicinity of the pad. And we have these very tall lightning towers out there that are designed to provide protection for just such an event, because we are launching from the lightning capital of the United States, the state of Florida. And the lightning system did its job, but we also had to perform due diligence and ensure that the vehicle was healthy and we had to do some analysis and then some system checks after the lightning strikes occurred.

We also had two hurricanes that caused us some delay. Hurricane Ian, which was a Category 4 hurricane, made landfall on the southwestern corner of the state of Florida, and then basically went right over the top of the Kennedy Space Center as it moved to the north and the east. And that forced a rollback to the Vehicle Assembly Building, and we protected the rocket and the spacecraft largely because that storm was so strong.

And then we had, what was Tropical Storm Nicole. And it barely became a Category 1 hurricane on November the 7th, just before our November 16th launch attempt that we decided to ride out at the launchpad. And that storm caused a delay. We were initially aiming for November the 14th as our initial launch attempt, and we had to move to the 16th to give the team a little more time.

And then on the very back end of the mission, we had weather issues as well. We had a cold front move through our primary landing zone off the coast of Southern California. About 50 miles off of the coast near San Diego in what they call the fleet training area that the U.S. Navy uses. And we had to move about 300 nautical miles to the south for our splashdown zone. And that resulted in a change to our reentry test to the spacecraft, and we had enough flexibility to handle all that.

I think the team worked through those things very methodically and was very patient. And our stakeholders as well were very patient with us as we worked through the weather and the hydrogen leaks and the engine bleed challenges. And those are the big ones that come to mind. But there were certainly a number of other issues that occurred throughout the course of the test flight.

Host: Your team put tremendous effort into planning and preparation. Did anything happen during the mission that you would categorize as unexpected?

Sarafin: Yes, there were a number of things that we learned. You know, every time you fly a vehicle for the first time, you have an idea or an understanding based on ground testing or modeling of how the system is going to perform. But you can’t test exactly like the vehicle is going to fly in the flight environment on the ground in many cases. And the one that really comes to mind for me is what we refer to as dazzling of the star trackers.

On the Orion spacecraft, we have what’s called an optical bench. And the optical bench is the mounting location for both of our star trackers as well as the optical navigation sensor. And it’s located on the service module side of things, near the thrusters that are used for in-space attitude control of the spacecraft. And what we learned very early in the mission, that by design these thrusters were thrusting above and within the field of view of the star trackers. And the star trackers were being confused. They’re highly sensitive instruments. They were being confused as they saw the plume and it was being lit by the Sun and they were being picked up. And we continued to get what was called a ‘component not ready’ flag. The star tracker saw something in the field of view, but it didn’t match what it expected. It knows where stars are, and other celestial objects are, but it was seeing something that it didn’t expect. So, the thruster plumes were dazzling the star trackers, and we had to reach back into our industrial base and folks that use similar systems and the team quickly resolved that through the Orion Mission Evaluation Room, what was going on.

We also had a couple other things that happened, one that we still don’t fully understand on the power system side of the Orion spacecraft. There’s something called a power conditioning and distribution unit, and there are two power feeds per solar array wing. There’s four solar array wings, so there’s eight of these power feeds that come in and they go through something called a latching current limiter and then to these power conditioning and distribution units. And then the power’s distributed throughout the spacecraft.

And the latching current limiters were opening, but nobody was commanding them to open. The ground wasn’t commanding it to open, and the spacecraft wasn’t commanding it to open. They were just opening. And while we don’t fully understand what was occurring there, we do have a robust enough design that the system was able to handle it. And the ground every time we saw one of these latching current limiters open, reducing the amount of power being fed to the system, we were able to close those and restore full redundancy. So, we did some testing during the course of the flight to try to reduce or eliminate legs on the fault tree as to where the issue is coming from. And we’re still looking at that one.

And then the last one I’ll say were bottlenecks with the data. We have a tremendous amount of information coming down and being recorded by the spacecraft, and we want it to get to the ground, but we have a wireless system, a Wi-Fi system for solar array wingtip images, as well as data recorded on board the service module. And that needs to be sent to the crew module for post-flight analysis as part of the flight reconstruction and engineering data review. And we had so much data being recorded for engineering purposes, for imagery purposes, for video, for just standard command and telemetry, that we discovered where the bottlenecks were. And we ran into a couple of issues with the camera controllers that stored the data being just uncooperative. And the team had to work through those.

So, there were a number of issues that we kind of knew we’d have data bottlenecks, but we didn’t fully appreciate it until we got into the flight. And then the latching current limiters and the star tracker dazzling were things that we just experienced in the flight environment for the first time, that we had never seen in ground testing.

Host: So many systems were tested through the Artemis I mission. As you’ve looked over the data, what stand out to you as key findings and benefits resulting from this mission?

Sarafin: Yeah, Deana, that’s a great question. I would say overall, the system performed as designed or in many cases better than we had predicted. I’ll give a few examples here.

On the Orion spacecraft side, the power has about 20 percent more margin than we anticipated, and that was the result of the solar arrays producing more power, but also the power consumption was lower than we had anticipated. Largely because the spacecraft was warmer than we thought it would be. And we didn’t need to use the heaters on the service module as much to keep the propulsion system thermally conditioned. The propulsion system itself was on predict or used slightly less propellant than we had predicted. I think the last set of numbers that I saw was we were about 2 percent less than we were predicting, which is actually a good thing. We’ve got more propellant there. And then the skip reentry of the spacecraft, when we came home, we were well within the five, I think it’s 5.4 nautical mile target to our splashdown location. In fact, we were 2.1 nautical miles from the target. And when you start thinking about the system that we’re flying here, the Orion spacecraft, and the fact that we essentially established our entry target line and performed our de-orbit maneuver from a quarter million miles away when we did the return powered fly-by by the Moon, that is remarkable precision.

And then on the rocket, the Space Launch System, it performed better than expected across the board. The boosters, the core stage, the RS-25 engines, the interim cryo propulsion system, the RL10 engine. Just from top to bottom on the rocket, we had remarkable precision there. I’ll give a few examples.

The insertion altitude for the core stage and shutdown of the four RS-25 engines, we were aiming for a 975 by 16 nautical mile insertion altitude. We ended up flying 972 by 16 nautical miles. That was the actual, and that is just remarkable precision for a system that large. We had a total velocity error of around seven feet per second at the guided cutoff in the insertion altitude. Again, which is remarkable precision for a core stage, that when the RS-25 engines are at full throttle are producing roughly two million pounds of thrust in total. And then the interim cryo propulsion staging, our RL10 engine all the way through the point of trans-lunar injection, was dead on it. It put us exactly where we wanted to be on our intercept trajectory to the Moon. And then all the disposal maneuvers, whether it was the core stage, the interim cryo propulsion stage, or the boosters, all those were per plan and well within our safety and public safety requirements.

And then on the ground side, our Exploration Ground Systems team and our Launch Operations team applied a lot of lessons learned from the wet dress rehearsals and the hydrogen leaks that we experienced and the engine thermal conditioning, the engine bleed issues that we had. And they worked through all those and got better every single time to the point where our third launch attempt, we successfully got off the mission. And there were folks recalling that for some shuttle missions, it took five or more attempts, and we were prepared for that. But I think that’s a testament to the team rolling in lessons learned.

All the umbilicals on the mobile launcher retracted as designed. And then the mobile launcher itself performed and passed all the structural inspections. We did have some damage on the mobile launcher and we anticipated some damage. The thing that I think we all noted was the elevator doors were blown off by the rocket. It produces 8.8 million pounds of thrust as it lifts off. The pad and the elevators were out of service, and we had to work to restore those. And then we did see some pneumatic system leaks on the mobile launcher on both the gaseous nitrogen and the gaseous helium side. And the team had to work to isolate those. But overall things were pretty much as expected and as predicted. All the software on the rocket, the spacecraft, the ground system, performed as expected. And again, I think that’s a testament to the quality of workmanship, the level of test and integration across the vehicle. It was a remarkable test flight.

Host: Mike, Artemis I was the 65th human spaceflight mission you’ve been involved with during your NASA career. Could you share some of the highlights of your NASA journey and where the Artemis experience ranks for you?

Sarafin: Yeah, that’s another great question, Deana. And yeah, looking back across my career, one thing that sticks in my head, is a mentor of mine probably eight years into my career said, ‘This job has the highest highs and the lowest lows.’ And certainly, Artemis I was top-five material in terms of highs. The lows, we’re being reminded that February the 1st of 2023, that’s the 20th anniversary of the loss of Columbia. And that was certainly the low for my career as well as many others in the agency.

The highs, I can recall on two separate occasions STS-129 and STS-132, being the Lead Flight Director where we worked with the Space Shuttle Program and the International Space Station Program to pull together logistics and assembly flights to the International Space Station. And on STS-129, took up a set of external logistics carriers with spares, pumps, and other equipment that have since been used to restore the International Space Station, the full functionality just through wear and tear of components.

But then on STS-132, we flew up the Rassvet module, which is the Russian docking port that’s currently on the International Space Station. And we flew that up and put that on the International Space Station. And it was for me, those two missions, STS-129 and STS-132, are still the top for me. And it was simply because we had a crew of astronauts involved and I was involved in the planning, the training, and the execution of the mission. But then the capstone at the very end was I got to go, in both cases, to the Kennedy Space Center and watch the space shuttle fall out of the sky and hear the double sonic boom as it approached the runway at Kennedy and glide to wheel stop at the runway and then go greet the crew as they came off the vehicle.

And that to me is by far the highlight of my career, and I hope to do that on future missions when we fly astronauts to the Moon. Artemis I is definitely top-five material but flying with a crew and preparing a mission with America’s finest and then getting to shake their hand as they come off the spacecraft at the very end of the mission, is something that’s hard to beat.

Host: Yeah. That’s absolutely amazing. How is mission management for a Moon mission different than other projects and missions?

Sarafin: Yeah, when we were preparing for Artemis I, we benchmarked the International Space Station, the Commercial Crew Program, the Space Shuttle Program, and a whole host of other programs to understand how we needed to be constructed from a risk management and decision-making standpoint. And I would just say that while there are similarities, the objectives are different, the risks are different, and the players or the team members are different. And I’ll give a few examples.

For Artemis missions, we’re flying to the Moon and it’s just harder. We’re coming back faster, meaning we’re coming back at 24,500 miles an hour at Mach 32, when we reenter the Earth’s atmosphere. Instead of 17,500 miles an hour Mach 25, when we come back from low-Earth orbit. We come back much hotter through the Earth reentry. The Orion spacecraft saw temperatures outside the heat shield approaching 5,000 degrees Fahrenheit or about half as hot as the surface of the Sun. The space shuttle when it came back was coming back at roughly 2,200 degrees Fahrenheit, and the heat profile was different.

It’s far farther. We are days away from Earth, rather than hours away from Earth. In low-Earth orbit, we’re hours away. But distance-wise, it’s a thousand times farther from Earth when we’re in the vicinity of the Moon at roughly a quarter million miles instead of roughly 250 miles in low-Earth orbit.

When you look at the Apollo Program, it’s different in the sense that we are going to the lunar South Pole on future missions, rather than the equatorial regions. And we are not necessarily going to have line of sight back to Earth. And that changes the risk profile and changes the complexity of the mission.

But when you compare it to Apollo, we are going back sustainably. Meaning that we are building an infrastructure and a capability here that is not to achieve a singular goal. It is there to explore and continue to build and go further outward. We’ll start with the Moon and we’ll go there sustainably and then we’ll go on to Mars. But we also have partnerships across the board. Whether it’s our international partnerships or our commercial partnerships. And that is also a difference from the Apollo Program. And those are some of the reasons why the Artemis Program is different, but in some ways, because it is human spaceflight has some similarities and some heritage that we’ve been able to leverage.

Host: What’s next with the Artemis Program?

Sarafin: Well, we have a series of increasingly complex missions ahead of us. On Artemis II, we are going to have our first crewed flight test where we’re going to send a crew of four astronauts into initially what is called a high-Earth orbit. And they’ll do a 24-hour shakedown of the Orion Spacecraft, test out the life support system, as well as perform a proximity operations demonstration before committing to the point of trans-lunar injection and doing a lunar fly-by on a free return trajectory after one full day in orbit. Artemis III is our lunar landing where we will conduct a joint mission with the Human Landing System. We will rendezvous with Orion after launching on the Space Launch System. We’ll rendezvous Orion with the Human Landing System that will be staged in a lunar orbit. And then take the Human Landing System, two astronauts will take the Human Landing System down to the South Pole of the Moon.

And then in the same approximate timeframe, we’ll be launching the foundational elements for the Gateway, which now creates that sustainability aspect. We will have the Power and Propulsion Element as well as the Habitation and Logistics Outpost, the HALO module, and the PPE of Gateway that’ll be launched commercially and then staged in the Gateway orbit. And then Artemis IV, we will send a crew to Gateway, again launching on the Space Launch System rocket. It’ll rendezvous with the Gateway and a lander. And then we’ll conduct a joint mission with Gateway and then send another crew of astronauts down to the surface of the Moon. And then Artemis V and future missions just get increasingly complex as we continue to build out and add to the sustainability of the capabilities in the vicinity of the Moon. So there’s a lot more ahead. And Artemis I was just the first step.

Host: What are the primary focus areas in 2023 to prepare for future Artemis missions?

Sarafin: Yeah. In terms of preparations in 2023, we will continue the production assembly, integration and test of the Orion spacecraft, the Artemis II spacecraft, which is currently at the Kennedy Space Center in the Operations and Checkout Facility. And we’ll prepare to move that over to the Exploration Ground System side in 2024 and get us ready there. But we also have some lessons learned from Artemis I that we’re going to roll in. Whether they are in terms of understanding our margins as we observed them to be during the Artemis I flight test and rolling those into our mission analysis and mission planning processes. But then there are also a number of operational lessons learned. Whether it’s the Mission Control Center interacting with the Deep Space network team, or whether it’s our ability to get data off of the spacecraft or understanding the power conditioning and distribution unit funnies that we’ve had.

There’s a whole host of lessons learned that we’re going to go through a very robust lessons learned process and roll those in, so that future flights — Artemis II and later crewed flights — can benefit from those. So that’s kind of our focus in addition to production of the Space Launch System core stage, and then readying the mobile launcher for the Artemis II mission. Installing the necessary crude systems, things like the emergency egress system and other crew safety features.

Host: Mike, we would love to learn more about those lessons learned. Maybe we can get back together again sometime in the future and talk through those.

Sarafin: Yeah, absolutely. There’s going to be a whole host of lessons learned that we’re going to talk through, and we’re very fortunate to launch Artemis I in the mid-November and splashdown in the mid-December timeframe. And now that we’re in 2023, we’re coming back after some well-earned rest after the holidays. And now we’re looking at what the hardware told us and what we learned here on the ground.

Host: Such exciting times. Thank you so much for joining us today. This has really, really been interesting.

Sarafin: Yeah, I appreciate your time, Deana, and thank you to your audience for just staying with us and for their interest in the Artemis Program.

Host: Mike’s bio is available on our website at appel.nasa.gov/podcast along with links to topics discussed during our conversation and a show transcript.

If you have suggestions for a future guest or topic on the podcast, please share your ideas with us on Twitter at NASA APPEL – that’s app-el– and use the hashtag Small Steps, Giant Leaps.

As always, thanks for listening.