Jeff Foust, for SpaceNews:
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.
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.
One question I’d like to see answered, that as far as I know has never been asked or commented on: how much time is needed between EM-1 and EM-2 for everything else except the Mobile Launcher?
I’d love to know when the EM-2 hardware will be ready across the board—the brand new Exploration Upper Stage, Orion’s Environmental Control and Life Support Systems, the second European Service Module, the second set of core stage hardware, and so on.
The Mobile Launcher may be the timeline limiting factor right now, but the other elements are non-trivial. All that considered, I’d bet that a second Mobile Launcher wouldn’t have helped shave off much time between EM-1 and EM-2.
SLS/Orion is a hardware-poor program. And don’t forget: this program is advertised on hardware heritage.