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cislunar outpost
A concept by Sierra Nevada Corporation for a cislunar outpost, one of several being studied by companies for NASA under contracts awarded last year. (credit: SNC)

A gateway to Mars, or the Moon?

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On Tuesday, President Trump signed into law the NASA Transition Authorization Act of 2017, the first NASA authorization bill in six and a half years. While past NASA authorization bills have been signed without fanfare, Trump held a signing ceremony in the Oval Office, featuring Vice President Pence, members of the House and Senate, acting NASA administrator Robert Lightfoot, and a couple astronauts, who presented the president with a personalized astronaut flight jacket after he affixed his signature to the bill.

“All of a sudden, there’s an urgency,” Gerstenmaier said of NASA’s cislunar outpost plans. “We’ve really got to start making some decisions about what that cargo is, who we partner with, how we build the equipment, what standards we put in place.”

The intent of the bill was not to create a new direction for NASA, but rather ensure that the current one remains in place for the time being. (Indeed, if all had gone as planned, the bill would have passed last December and been signed into law by President Obama.) Trump, in his comments at the signing ceremony, didn’t offer many hints about what his vision for NASA might be. “Today we’re taking the initial steps toward a bold and brave new future for American space flight,” he said, without elaborating on what the future may hold.

One element of the bill that attracted media attention was a provision that called on NASA to develop a plan to send humans to Mars in 2033. A report, due to Congress 180 days after the bill’s enactment last week, will include a “technical development, test, fielding, and operations plan” for such a mission, along with a budget profile. The bill, though, doesn’t explicitly make such a mission a goal, instead, the bill establishes as goals less specific calls for human missions beyond Earth orbit, including Mars. The Mars 2033 report doesn’t even specify what kind of human Mars mission: a lander versus, more likely, a flyby or orbital mission.

There remains speculation, though, that NASA’s human spaceflight trajectory may be bent back towards the Moon, if not as a long-term destination then as a major milestone on NASA’s “Journey to Mars.” Some see NASA’s ongoing study of putting a crew on the first SLS/Orion mission, EM-1, for a trip around the Moon as a first step in a new, lunar-centric exploration effort.

What else would such a shift in direction mean for NASA’s human spaceflight program? In the near term, not much, it seems. Under the Journey to Mars concept, NASA planned to spend the 2020s in cislunar space, its “Proving Ground” to test technologies before attempting human missions to Mars. That included creating a habitat in cislunar space, sometimes called a “gateway,” that would be used for long-duration missions of up to a year before going to Mars.

That work remains on track, agency officials said earlier this month. “There’s starting to be a sense of urgency,” said Bill Gerstenmaier, NASA associate administrator for human exploration and operations, during a March 8 panel session at the American Astronautical Society’s Goddard Memorial Symposium outside Washington, DC. There had been plenty of time before, he said, to decide what elements of a proposed cislunar habitat should be developed, and in what order they could be launched as secondary payloads on future SLS missions.

“All of a sudden, there’s an urgency,” he said, pointing to the planned mid-2021 launch of the second SLS/Orion mission, EM-2, which will be the first with the more powerful Exploration Upper Stage that will allow for large secondary payloads. “We’ve really got to start making some decisions about what that cargo is, who we partner with, how we build the equipment, what standards we put in place, et cetera.”

“You’re going to see us, over the next several months, starting to make some pretty crisp decisions about what goes on those flights and what things are there,” he said.

“You’d think we would have [environmental control and life support] nailed, but it’s a hard, hard problem,” said Chambers.

Those decisions may ultimately include what roles commercial partners have in the cislunar gateway. Last year, NASA awarded contracts to six companies as part of the second phase of the Next Space Technologies for Exploration Partnerships (NextSTEP). The awards, running through late next year, cover the development of concept studies or ground prototypes of a habitat that could be used for deep space missions, or repurposed by the companies to support commercial space stations in low Earth orbit.

Five of the six companies—Bigelow Aerospace being the exception—participated in a panel session at the symposium a day after Gerstenmaier’s panel to discuss their NextSTEP work. While taking different technical approaches, all have similar visions for what a cislunar outpost could do.

“What we’re really focused on in NextSTEP phase 2 is long-duration ECLSS systems,” said Rob Chambers, Orion production strategy lead at Lockheed Martin, referring to environmental control and life support systems. “You’d think we would have ECLSS nailed, but it’s a hard, hard problem.”

Lockheed Martin’s approach, not surprising, leverages the capabilities of the Orion spacecraft that it is the prime contractor for. Others, though, also expect SLS and Orion to play central roles in the development of a cislunar outpost. “Space Launch System and Orion are critical components,” said Michael Fuller, senior manager of NASA space systems at Orbital ATK. The upgraded SLS with the more powerful upper stage “provides a critical capability to get both crew and cargo in various forms to the Moon, and to the Moon’s vicinity.”

“I love all rockets, but for the first couple of years there it’s going to be SLS and Orion putting our astronauts and cargo out there,” said Matt Duggan, exploration manager at Boeing. Gerstenmaier, a day earlier, had suggested that the cislunar outpost could be supported by other launch vehicles, given the projected once-a-year flight rate of the SLS.

The companies working on NextSTEP studies are seeking, in many cases, to repurpose existing systems for use in a cislunar outpost. “Our concept is to leverage hardware that is already out there,” said Steve Overton, a program manager for integrated space systems at Aerojet Rocketdyne, partnered with Sierra Nevada Corporation. That includes elements of Sierra Nevada’s Dream Chaser vehicle: an extended version of the cargo module being developed for Dream Chaser missions to the ISS would be used in the concept.

No one, perhaps, is taking the idea of repurposing further than Ixion, a team consisting of NanoRacks, Space Systems Loral, and United Launch Alliance. It plans to convert a Centaur upper stage left in orbit after a launch into a habitat module, for use either on the ISS or a cislunar base.

“We’re recycling,” said Michael Johnson, chief designer at NanoRacks, emphasizing that few changes are needed to the upper stage prior to launch, with the outfitting done once it’s in orbit. “What we call the ‘scarring’ process is very minimal.”

Those concepts call for the development of a habitat somewhere in cislunar space: one of the Earth-Moon Lagrange points, for example, or the distant retrograde orbit around the Moon popularized by the Asteroid Redirect Mission. Those options work if the habitat is simply in cislunar space as a place to test out systems for a long-duration Mars mission. What if NASA instead wants to send humans to the surface of the Moon?

Some of the companies have already been planning how their outposts could support missions to the lunar surface, originally for international partners who showed a greater interest in such missions. “None of it becomes obsolete,” Duggan said of Boeing’s plans. “We may now be talking more about a US trip to the surface of the Moon, but an international trip to the surface of the Moon was always in the trade space.”

“The outpost itself is basically a gateway to anywhere,” said Orbital ATK’s Fuller. “Whether you’re going to the Moon, whether you’re going to build that vehicle to go to Mars, what have you, we think it’s complementary.”

“I fear a little bit… that if we want to go to Mars, but we decide to go to the Moon first, we’ll be there 20 or 30 years,” and Grunsfeld.

“If we do decide as Americans to do a landing, I’m hoping that we look carefully at what the lander design is for Mars, and how you modify that,” said Chambers. “It may not be obvious that we want to do an Altair, which was the Constellation lander, with a separate throwaway upper stage.”

“The concern is that, if you design for the Moon, a point solution,” he added, “it may not be able to feed forward into Mars.”

A related concern is that a lunar detour on the Journey to Mars could delay the arrival of humans there well beyond the aspirational 2033 date in the legislation.

“Are we going to the Moon or are we going to Mars?” asked John Grunsfeld, a former NASA astronaut and former head of NASA’s science mission directorate, in a conference wrapup panel. “I fear a little bit… that if we want to go to Mars, but we decide to go to the Moon first, we’ll be there 20 or 30 years.”

He added he had nothing against going to the Moon, but that it was a choice facing NASA and the nation. “If we decide to go down that road, we should make sure we get the most out of that lunar program—determine the highest-priority science, use it to build big telescopes and do other things—to justify the very high cost, both in dollars and technology, and opportunity costs,” he said, “because many of us won’t ever see anyone set foot on Mars.”