SLS EM-1 launch
NASA officials said Feb. 24 that a study about flying a crew on EM-1 will constrain its work to plans that would allow a launch by the end of 2019. Credit: NASA

WASHINGTON — A NASA study now underway to examine the prospects of flying a crew on the first Space Launch System launch will constrain its evaluation to missions that can be flown by the end of 2019, agency officials said Feb. 24.

In a media teleconference organized by NASA on only a few hours’ notice, officials said the study announced Feb. 15 regarding flying a crew on the Exploration Mission 1 (EM-1) flight of the SLS and Orion will examine the pros and cons of such a proposal, but not make a formal recommendation.

“I want to stress to you this is a feasibility study, so when we get done with this we won’t come out with a hard recommendation, one way or the other,” Bill Gerstenmaier, NASA associate administrator for human exploration and operations, said of the EM-1 study. “We’re going to talk about essentially the advantages and disadvantages of adding crew to EM-1.”

The study will look at what needs to be done to both SLS and Orion to allow a crew to fly on the EM-1 mission, using the spacecraft and launch vehicle already under development for a mission currently not designed to carry a crew. NASA chose that approach over the alternative of accelerating EM-2, which is currently planned to be the first crewed mission, launching in 2021.

“We kind of ruled out trying to accelerate EM-2 and focused our attention on the potential to adding crew to EM-1,” said Bill Hill, deputy associate administrator for exploration systems development. That, he said, was because of modifications to ground systems needed to accommodate the larger Exploration Upper Stage (EUS) that will be used on SLS missions starting with EM-2.

A “brief assessment” about one month ago on the feasibility of adding crew to EM-1 concluded it was in the “realm of possibility,” Hill said, which the new study will examine in greater detail.

The study, which Gerstenmaier said was directed by the team of Trump administration appointees assigned to NASA in conjunction with agency acting administrator Robert Lightfoot, does not have any specific schedule or budget restrictions on adding a crew to EM-1. However, he said he’s limiting scenarios to those where the mission, currently scheduled to launch in late 2018 without a crew, could launch with a crew no later than the end of 2019.

“I didn’t want to go much beyond 2019,” he said. “I felt that if we went much beyond 2019, then we might as well fly EM-2 and actually do the plan we’re on.” That constraint, he added, also forces a relatively rapid decision about whether or not to fly a crew on the mission.

The concept being examined for a crewed EM-1 mission would be to fly a two-person crew on Orion on a trajectory similar to what’s already being considered for EM-2. After spending a day in Earth orbit after launch, Orion would then fly a free-return trajectory around the moon, returning eight to nine days after launch.

That mission can be flown with the less powerful Interim Cryogenic Propulsion Stage (ICPS) upper stage that will be used on EM-1, rather than the EUS planned for EM-2 and later missions. “We don’t need the full capability of the EUS,” Gerstenmaier said.

However, the ICPS, derived from the Delta 4 upper stage, would need modifications that would allow it to fly a crewed Orion. “One of the tasks we’ve asked the team to go look at is what changes we need to make to this upper stage to do the mission we would like it to go do,” he said. That would include possibly adding micrometeoroid debris protection to the stage.

Gerstenmaier said the study will also examine the increased risk of flying a crew on EM-1. “We need to go look at what do we really gain by putting crew on this flight. Does this really advance significantly our overall ability to get to a capability to take humans, routinely as it can be, to the vicinity of the moon and operate safely?” he said. “We’ll actively trade this risk against the benefits.”

Gerstenmaier said preliminary results from the study should be ready in about a month. He added he believes the results will fit into budget discussions with the White House and Congress as it prepares a fiscal year 2018 budget request for NASA.

“We know it’s going to take a significant amount of money, and money that will be required fairly quickly to implement what we need to do,” said Hill of any plan to add crew to EM-1.

Both Gerstenmaier and Hill had no current preference whether or not to fly a crew on EM-1, saying they will let the study guide their thinking on the idea. They noted they expected benefits to the program regardless of the final decision whether or not to fly astronauts on EM-1.

“Even we don’t decide to go do this, we will now go back and we’ll look and say, ‘Hey, some of the things we found in this study we should probably implement on EM-1 anyway because it’s going to make a more robust program,’” said Gerstenmaier.

“If we can fly the EM-2 profile mission on EM-1,” said Hill, “that opens up EM-2 to do more.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...