SPACENEWS by Jeff Foust — May 2, 2017
NASA may not know exactly where it’s going in human spaceflight, but it knows how it will get there.
The agency’s current plans, of course, call for human missions to Mars, first into orbit around the red planet as soon as 2033, followed eventually by trips to the Martian surface. But those plans are clouded by the uncertainty that comes with a change in presidential administrations. NASA is waiting on the nomination of a new administrator and expected re-establishment of the National Space Council to provide guidance for the agency. NASA not only does not have a detailed fiscal year 2018 budget proposal, it’s still waiting on a final 2017 spending bill, nearly seven months into the current fiscal year.
Yet, despite that uncertainty, NASA is providing more details about its future steps in human spaceflight beyond the International Space Station. In recent weeks, agency officials have laid out its exploration vision for the 2020s, including the creation of a small space station in the vicinity of the moon and a spacecraft capable of missions beyond cislunar space, specifically to Mars.
Building the gateway
The idea of some kind of human-tended facility in orbit around the moon is not new: NASA has suggested for years that such an outpost might be developed in the “proving ground” phase of its exploration plans, allowing astronauts to test technologies needed for missions to Mars, but offered few specifics about it.
In recent weeks, though, NASA had laid out more details about what such an outpost might look like and how it could be built, driven by the need to start planning payloads for the initial missions to develop it.
“There’s starting to be a sense of urgency” about identifying those payloads, said Bill Gerstenmaier, NASA associate administrator for human exploration and operations, in a March 8 talk at the Goddard Memorial Symposium.
That urgency, he said, is because the first Space Launch System flight to deploy elements of that outpost, Exploration Mission 2 (EM-2), could launch within four years. “We’ve really got to start making some decisions about what that cargo is, whom we partner with and how we build the equipment,” he said.
Three weeks later, in a March 29 presentation to the NASA Advisory Council (NAC), Gerstenmaier talked more about what NASA calls the Deep Space Gateway. In essence, he offered what many in industry, and in Congress, had long been seeking: an architecture of missions that could lead up to the first human expedition to Mars.
That effort starts in earnest with the EM-2 mission, which NASA still plans to launch as soon as August 2021. (An April 13 report by NASA’s Office of Inspector General concluded that EM-2, and EM-1 before it, will probably be delayed.) EM-2 is the first flight of the upgraded Block 1B version of SLS, with the more powerful Exploration Upper Stage that increases its payload capacity by up to 50 percent.
That additional performance allows NASA to fly so-called “co-manifested payloads” weighing up to about 10 tons each along with an Orion spacecraft. Those payloads would fit in the adapter between the Orion service module and the upper stage.
EM-2, in the plan Gerstenmaier presented, would carry a 40-kilowatt power and propulsion system. It would be followed by EM-3, carrying a habitation module, and EM-4, a logistics module that might include a Canadian-built robotic arm.
“Essentially, in three SLS flights we can have the Deep Space Gateway assembled and ready to do operations in the vicinity of the moon,” he said, although an airlock could be added on the next SLS mission.
Those SLS missions, Gerstenmaier said, would be augmented by commercial resupply flights, delivering cargo to support operations there. “Flying just once a year isn’t going to work,” he said of the planned cadence of SLS launches. “We’re going to have to have some commercial flights for logistics and other activities.”
Gerstenmaier envisions crews of four astronauts spending up to 42 days at a time at the Deep Space Gateway. Doing what, though? Gerstenmaier said NASA has started discussions with scientists and engineers about research they might like to do there, or technologies they wish to demonstrate that could support NASA’s exploration plans.
The gateway would serve as the staging area for the next phase of NASA’s exploration plans, starting with the EM-6 SLS launch planned for 2027. That would be a dedicated cargo mission, launching a 41-ton spacecraft called the Deep Space Transport: a vehicle with the habitation and transportation systems needed for long-duration human missions beyond Earth orbit, including Mars.
Why launch an entire spacecraft at once, rather than building it up like the gateway? “It needs to be optimized from a weight standpoint,” Gerstenmaier said, which means doing away with a less-efficient modular approach.
Earlier concepts had the gateway evolve into the transport, but Gerstenmaier said that NASA needs more time to work on key technologies, like long-duration life support systems, that won’t be ready when the gateway is assembled in the first half of the 2020s.
“We thought it was better to think of these as two separate entities, with a little bit different technology and capabilities, that flow better from a timing and budget and resource development standpoint,” he said.
The Deep Space Transport would initially be docked to the Deep Space Gateway, where later SLS flights would deliver fuel and other cargo. In 2029, after the delivery of a four-person crew to the gateway on the EM-9 mission, the Deep Space Transport would depart for a one-year shakedown cruise, most likely not straying far from cislunar space.
If all goes well, the same vehicle would be used, after another pair of SLS launches to refuel and restock it, for a Mars mission in 2033. “We’ve spec’ed this thing to be able to make three flights to the vicinity of Mars and come back,” he said.
More:
http://spacenews.com/the-moon-is-the-gateway-to-nasas-exploration-future/
