Spaceflight Insider

Insider Interview: Former astronaut details what is required to send crews to Mars

nasa-orion-reentry into Earth's atmosphere NASA image posted on SpaceFlight Insider

NASA currently plans to send astronauts to Mars some time in the 2030s. Former shuttle astronaut and a representative with one of the firms working toward this achievement, Kent Rominger, spoke with SpaceFlight Insider as to what is required to accomplish this feat. Image Credit: NASA

KENNEDY SPACE CENTER, Fla – There are few people in the world today who have traveled into the black of space, fewer still who have commanded missions to orbit. ATK’s Kent Rominger – is both and he is currently one of the people working to enable NASA’s crewed deep space exploration objectives. During the lead up to the launch of NASA’s Exploration Flight Test 1 (EFT-1 ) SpaceFlight Insider sat down with Rominger to talk about how NASA’s Orion spacecraft, powered aloft by the new heavy-lift Space Launch System or “SLS” booster – is being built to send crews to Mars.

NASA has stated Orion is the spacecraft which will aid the space agency in sending the first crews to the Red Planet and that it is hoping to accomplish this feat sometime in the 2030s. EFT-1 was a chance for those working within the space industry – to relay what they were doing to send astronauts to the dusty plains of Mars. Rominger currently works for Utah-based ATK, the firm tasked with producing the solid rocket boosters which are planned for use on SLS. Rominger spoke at length about what is required to allow this to happen as well as his company’s efforts to help achieve this.

SpaceFlight Insider: First off Kent, we want to thank you for taking the time out of your busy schedule to chat with us today.

Rominger: “It’s my pleasure; this is amazing weather we’re having!”

SpaceFlight Insider: Yes it is. Can you give us some basic details about what your company is doing to get crews to Mars? Do we really need a booster the size of SLS to send crews to the Red Planet?

Rominger: “I’m very involved in the system that is being built to take us to Mars, SLS. This is incredibly exciting. There is always talk of: ‘How capable of a system do you need?’ As we have watched our program evolve, it has gone from ‘super’ large – to just ‘extra’ large. As times goes on – we hone in on the right-sized system – but then you need to decide, how do you really get to Mars? Getting to Mars – is tough. It is a very, very difficult mission.”

Five segment solid rocket booster Space Launch System SLS ATK photo posted on SpaceFlight Insider

NASA and ATK have tested a five-segment variant of the solid rocket booster which is planned for use on SLS. Photo Credit: SLS

SpaceFlight Insider: Talk a bit more about that.

Rominger: “Sure, when we go to the International Space Station – it is only a couple hundred miles away. If you need to come home, you can jump into your capsule and once you conduct your deorbit burn – you’re just an hour away from the surface of the planet.

When you go to Mars and you are using similar types of propulsion systems, you are, at best, eight-to-nine months to get there. This is because Mars and the Earth are both going around the Sun – there’s this thing called phasing, where you want to make sure that the phasing is opportune.

So, once you are at Mars you could turn around and come right back. But most planners will tell you, no, we want to take advantage of being at Mars. So now you are committed to actually staying there for a while once you have stayed past four-to-six weeks to eight or nine months until the phasing aligns back up.”

SpaceFlight Insider: Can you provide us with a little more information on how phasing works?

Rominger: (laughs) “If I had some models, it would be a little easier to explain. Essentially, Earth and Mars are in separate orbits. At certain points Earth is on one side of the Sun and Mars on the other. Then there are times when both planets are on one side of the Sun – and close together, relatively speaking. Mission planners try to schedule flights for when this takes place so as to optimize their chances of success and minimize the amount of fuel that is required to carry out a mission.”

NASA crewed habitat lander image credit NASA posted on SpaceFlight Insider

NASA still has several elements that it needs to develop and have produced before it is able to carry out crewed missions to the Red Planet. Image Credit: NASA / GSFC

SpaceFlight Insider: In terms of ATK’s involvement with NASA’s efforts to land crews on Mars, the Space Launch System, can you provide us with some specifics about them?

Rominger: “Sure, the five segment boosters that are being built for SLS have quite a heritage. They evolved from the space shuttle booster, which had four segments; the fifth segment makes the booster about 25 percent larger, so you have higher thrust. But, the specific impulse that matters is the amount of energy that you get out of that booster. When you start looking at putting large amounts of mass to space – that energy becomes very important.

For getting off the planet, for getting out of the gravity well that you and I are sitting in at this very moment – you need a huge amount of thrust and you care about energy density. The culmination of those two results in solid (fuel) as the ideal propulsion to get you off of the planet. Solids are known for high thrust, high density, but, in fact they typically don’t burn long, solid-fueled boosters will only burn for a couple minutes in the space shuttle world that I was always kind of fascinated that we got 6 million pounds of our thrust – out of the two solid rocket boosters and a little over a million pounds of thrust out of the three liquid-fueled engines.

Once we got out of Earth’s gravity well, that little more than a million pounds of thrust was fine. But we need the solids to accomplish this.

The five segment boosters will allow SLS to place more than 100 metric tons into orbit. What we’re finding is that, depending on the mission design, which targets how much payload that you want to put into orbit – and we now really care about how much you can put into deep space more so than a low-Earth orbit. We’ve kind of always used the LEO metric – because that has been where we have always been and it’s what we understand. The reality of it is, is that we really ought to start transitioning to escape velocity-type metrics cause that is what we care about and we want our system to be optimized for that.

When a system lifts off, you need a high amount of thrust – but after that you care a huge amount – about velocity. Velocity, in turn, is important, because that is how you go into an escape velocity to venture out into our solar system and into deep space.”

NASA Orion spacecraft with ESA provided Service Module in orbit above Earth NASA image posted on SpaceFlight Insider

NASA currently plans to carry out the first launch of the complete stack of Orion/SLS in 2018. Image Credit: NASA

SpaceFlight Insider: Talk to us a bit about what we can expect to see out of the early versions of SLS.

Rominger: “So, initially with the first block of the SLS it’s called the 70 metric ton version – it actually throws a little bit more than that. The next version, the Block 1B, includes a more capable upper stage – it’s around 105 metric tons to LEO. But more importantly you really gain a lot out into deep space, with that upper stage, same set of boosters, which can now be evolved to push that 105 metric tons – to 130 into LEO but, again, I keep going back to the deep space escape velocity – this really has become the metric that we care about.”

SpaceFlight Insider: Because of the intent to send crews to Mars?

Rominger: “Precisely.”

SpaceFlight Insider: Can you provide us with details about how NASA is planning on accomplishing this?

Rominger: “Sure, it looks like NASA is planning on getting humans to Mars by starting out in a kind of proving ground out in cislunar space, potentially putting a very modest habitat out there – with the theory being we launch this habitat on one SLS flight, in fact you can launch the habitat and the crew all on one mission. With that you have the habitat set up and Orion has a 21-day capability – so now you can dock Orion to the habitat and allow it to go dormant, where it can stay for months, now crew can stay out in deep space for weeks or even months at a time.

After they have completed their mission out in deep space they would fire Orion back up and come home. It’s kind of a really neat stepping stone. Today, we are really good at working in low-Earth orbit, but, the reality of it is, if there’s a problem your hours away from the surface of the Earth.

The next logical step on the road to Mars is going about eight days away from the planet. That creates an entirely different scenario. But these are all steps that we are going to have to take when we commit ourselves to going to Mars.”

SpaceFlight Insider: It looks like you have another appointment, let me thank you for taking the time to speak with us today.

Rominger: “No problem, have a great day.”

If everything continues to go as planned, the first flight of both Orion and SLS will be in 2018. Dubbed Exploration Mission 1, this flight will be another unmanned test of Orion, as well as the first time that the SLS takes to the skies. The agency hopes to have astronauts riding the spacecraft-launch vehicle combination as early as 2021.

After these flights have been carried out and the duo’s capabilities have been validated, NASA hopes to conduct ever more complex missions to an asteroid and, eventually, Mars.


ATK image of Kent Rominger posted on SpaceFlight Insider

Photo Credit: ATK

During his time in the U.S. Navy, Rominger has been awarded a wide array of honors which include, but are not limited to, Distinguished Flying Cross. Defense Meritorious Service Medal, NASA Distinguished Service Medal, U.S. Naval Test Pilot School. Naval Air Test Center Test Pilot of the Year (1988).

Rominger is a veteran of Operation Desert Storm where he served as a Operations Officer on board the aircraft carrier U.S.S. Nimitz. Rominger has logged more than 7,000 flight hours in more than 35 types of aircraft and has completed 685 carrier landings.

He was selected to be an astronaut in March of 1992. As noted he flew five shuttle missions: STS-80 and STS-73 which flew on board Columbia, STS-85 and STS-96 both on Discovery and STS-100 which flew to orbit on board the youngest of NASA’s fleet of orbiters – Endeavour. After his final flight, Rominger had logged 1,600 hours in space.

During his time with NASA, Rominger also served as the Chief of the Astronaut Office (Shuttle Operations Branch), Deputy Director, Flight Crew Operations, and Chief of the Astronaut Corps. After retiring from NASA in 2006 – he joined ATK.



Welcome to SpaceFlight Insider! Be sure to follow us on Facebook: SpaceFlight Insider as well as on Twitter at: @SpaceflightIns






Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology,, The Mars Society and Universe Today.

Reader Comments

Good article.

I’m still a little stunned after reading Mr. Rominger’s credentials……wow!

As I understand the contract for SLS boosters will be up for grabs. ATK may have 30 years of shuttle experience but it would be nice to see the world’s most powerful rocket use cleaner, liquid boosters.

Really huge pressure-fed boosters would be nice- I like to call it “the methane monster”- but unfortunately all the technology is wrapped up in solid fuel. They do pollute but compared to things like the coal industry it is a drop in the bucket.

How many SLS launches would it take to put up all the hardware you would need? Habitat, fuel tanks, earth departure stage, et cetera at 105 tons per launch?

I think the question is how many launches to set up a base on the Moon where a Mars mission can then be assembled. The Moon has to come first for several reasons. And if you build spaceships that can go to Mars then bypassing that cold dim rock and going to places like Ceres and the moons of the gas giants becomes far more attractive. Mars is more a P.R. destination than reality.

building electric cars produce 1000000 times the exhaust of a solid

⚠ Commenting Rules

Post Comment

Your email address will not be published. Required fields are marked *