NASA No Longer Seeks to Build a Second Mobile Launcher for SLS Megarocket

CAPE CANAVERAL, Fla. — NASA is not planning to develop a second mobile launch platform that could shorten the gap between the first two Space Launch System missions as it makes few changes in general to its exploration programs despite a renewed focus on the moon.

The mobile launch platform, originally built for the Constellation Program and currently being modified to support the SLS, will be used for one launch of the initial Block 1 version of the SLS, designated Exploration Mission (EM) 1. That platform will then have to be modified to accommodate the taller Block 1B version that will be used on second and subsequent SLS missions.

Agency officials said late last year they were considering starting work on a second mobile launch platform designed from the beginning to accommodate the Block 1B version of the SLS. They argued that doing so could shorten the gap of at least 33 months between the first and second SLS missions caused in part by the modification work to the existing platform. The Aerospace Safety Advisory Panel endorsed the development of a second mobile launcher at an October 2017 meeting as a way to minimize "safety difficulties" a long break between SLS missions could create. [In Pictures: How NASA's EM-1 Moon Mission Will Work]

However, NASA's fiscal year 2019 budget proposal released Feb. 12 made no mention of developing a second platform. "We did not include it in the president's budget request," said Bill Hill, deputy associate administrator for exploration systems development, during a panel discussion Feb. 28 at the 45th Space Congress here. "Right now we're on our baseline path to modify the mobile launcher after EM-1."

Hill confirmed after the panel discussion that a second mobile launcher was no longer under consideration, citing a need to fund other exploration programs within the overall budget. "We've got a funding level, and it's got to be shared among the various priorities," he said.

He said that while there's not much they can do to shorten that gap between EM-1 and EM-2, they're confident they understand what it will take to modify the platform after EM-1. "We've got a good handle on it, a good understanding of what it's going to take," he said of the modifications, which involve extending the tower by more than 13 meters and redoing elevators, wiring, plumbing and other systems.

Hill and Mike Bolger, manager of NASA's Exploration Ground Systems program, also addressed reports that the tower on the platform was leaning. Those reports cited a "deflection" in the tower from the vertical, but one that NASA said did not require corrective action.

"It is very, very close to perfectly plumb," Bolger said. Any variations from the vertical, he said, are well within tolerances for the structure. If not, he said, NASA would not have gone ahead with the installation of a crew access arm on the tower just earlier this week. "It's just not an issue."

"It's a lot about nothing," Hill said.

Other aspects of NASA's overall exploration program have also seen few changes despite a shift in policy, such as the directive signed by President Trump in December calling for a human return to the moon as an interim step towards Mars.

"We took a little turn from the Mars campaign. It's not a big turn," Hill said, adding that human Mars exploration remained the "horizon goal" for the overall program. "We've worked really well with the new administration and the National Space Council in getting to where we are today."

That turn, he said, will include missions to the surface of the moon, although how NASA will do so, and with what partners, is still being analyzed. "For us, we're going to do some lunar surface activities, working with international and commercial partners, see if we can develop a lunar base economy," he said. "We'll see where we go from there."

That effort includes retaining, but renaming, a human-tended facility in cislunar space that the agency introduced last year as the Deep Space Gateway, prior to the formal shift in policy to return humans to the moon. "That really hasn't changed," Hill said. "Our approach to that remains the same even under the new administration."

The facility is now called the Lunar Orbital Platform – Gateway. "The administration wanted to change it slightly, thinking that maybe the Gateway was part of the last administration," he said, adding the concept was introduced in the early months of the current administration. "Our compromise with them was to call it the Lunar Orbital Platform – Gateway."

This story was provided by SpaceNews, dedicated to covering all aspects of the space industry.