With a Republican White House and a Democratic House of Representatives, it almost goes without saying that the President's fiscal year 2020 budget request won't get far within Congress. Yet with NASA's budget, there are intriguing hints about the increasingly commercial nature of lunar exploration.
Two sources familiar with the thinking of Vice President Mike Pence—who leads US space policy—have said he is frustrated with the slow pace of the nation's efforts to send humans to the Moon. In particular, he is growing tired of delays with NASA's Space Launch System rocket, which was originally due to launch in 2017 and is now likely delayed until 2021 at the earliest.
Notably, President Donald Trump's budget request calls for a 17 percent reduction in the budget for NASA's Space Launch System rocket, once viewed as the backbone of the space agency's efforts to explore deep space. The president's budget request chips away at the supremacy of the SLS booster in three important ways.
First of all, with the budget cut, the president's proposal "defers" funding for the Exploration Upper Stage. That's the more powerful second stage that would allow a future version of the SLS rocket to lift both the Orion capsule and large chunks of payload to lunar orbit.
"The Budget proposes reforms to the SLS program to prevent the program’s significant cost and schedule challenges from further diverting resources from other exploration activities," the president's budget overview states. This is a reflection of a desire to complete the initial, oft-delayed "Block 1" version of the SLS as expeditiously as possible. Future upgrades will have to wait (or may never come at all).
The budget also opens the door to commercial launches of cargo to lunar orbit, including comments of its proposed Gateway station there. "Lunar Gateway elements would be launched on competitively procured vehicles, complementing crew transport flights on the SLS and Orion," the document states.
This is a significant change from the previous plans, which called for "co-manifesting" the Orion spacecraft alongside modules of the Gateway onto a single SLS rocket, with its enhanced upper stage. The Block 1 version of the SLS is not powerful enough for such co-manifested missions.
Finally, the budget says that a robotic probe to Europa, due to launch in the 2020s, will not launch on the SLS booster. Instead, it will launch on a private rocket. (As Ars previously reported, this almost certainly would be SpaceX's Falcon Heavy). "By launching that mission on a commercial launch vehicle, NASA would save over $700 million, allowing multiple new activities to be funded across the Agency," the budget document states.
With this proposal, therefore, NASA is taking away a key upgrade to the Space Launch System's upper stage, proposing to launch Gateway on commercial rockets, and removing a high-profile mission from the launch manifest—the Europa Clipper. This leaves just one real task for SLS, which no commercial rocket can presently perform: the direct delivery of a crewed Orion capsule to a high lunar orbit.
Bridenstine on SLS
NASA Administrator Jim Bridenstine unveiled the budget during a speech at Kennedy Space Center on Monday. In it, he spoke about "reusability" as an essential cornerstone to the space agency's return to the Moon. By going with reusable systems, Bridenstine said NASA's plans for human missions to the Moon and eventually Mars would be affordable and sustainable.
The agency's large rocket—which has cost NASA $12 billion so far to develop, and has an annual budget of around $2 billion—is an exception to this. "SLS is not reusable, but it is a critical piece of the architecture that enables us to deliver reusability to the Moon," Bridenstine said.
The administrator then added some confusion to the president's budget by contradicting its provision to defer funding for the Exploration Upper Stage. "We're talking about a rocket that's bigger than any rocket that's ever been built before in human history," Bridenstine said. "To take not just our astronauts to the Moon, but at the same time co-manifested payloads."
The US Senate will have much to say about this budget before it is done. In years past, the Senate Appropriations Committee, under the direction of its chairman Richard Shelby, has plussed up the administration budgets for NASA's SLS rocket.
The Alabama senator reiterated as much last week during a session of the Space Transportation Association. Another speaker was Jody Singer, the director of Alabama's Marshall Space Flight Center, where the SLS rocket is managed.
"As chairman of the appropriations committee, I have more than a passing interest in what NASA does. And I have a little parochial interest, too, in what they do in Huntsville, Alabama," where Marshall is located, Sen. Shelby said. "Jody, you keep doing what you're doing. We'll keep funding you."
Shelby and his staffers will no doubt understand the implications of the president's budget and what it would mean for the utility of the SLS rocket. If enacted, these changes could spell the beginning of the end of the SLS rocket, especially if it experiences further delays. This will be one budget battle that is interesting to follow.