NASA's role as the provider of pump priming funding for the commercial spaceflight industry is set to come under further scrutiny despite the recent award of the latest Commercial Crew Development (CCDev) contracts.
The latest beneficiaries of NASA's largesse are SpaceX, Blue Origin, Sierra Nevada and Boeing in the CCDev 2 competition.
It is no surprise that many potential competitors are reliant on NASA funding to put their products into orbit; experienced spacefarers Orbital Science are rumoured to have dropped building plans after losing both CCDev awards.
Despite what is billed to be the strongly corporate nature of the programme - in that the aerospace industry provides the bulk of the capital - some companies are reliant on government funding. If CCDev's third round is cancelled, what programmes will survive?
Government funding has traditionally been a strong stimulus for aerospace programmes, from classified technology development to pre-launch loan funding for commercial aircraft.
Private spaceflight is a nascent and potentially very lucrative industry - however, the massive upfront development costs required may not be met by similar revenue streams: only a few people on Earth can afford to pay their way.
Space tourists to date have launched on Soyuz for $20 million per flight; only seven tourists have flown, with a single repeat customer.
Therefore, outside NASA, interest has come from countries seeking a way to launch their own missions without needing to develop the resources.
Bigelow Aerospace, which is developing a space station of sorts, has signed agreements with organisations in six countries: Japan, Singapore, UK, Sweden, Australia and the Netherlands. Bigelow has also signed an agreement with Boeing - Bigelow will provide the destination and Boeing will provide transport in the form of its CST-100 capsule.
But Boeing maintains that NASA funding is crucial; the aerospace behemoth won two rounds of CCDev money, including the largest single award of CCDev 2 with $92.3 million. "If for some reason we weren't selected to continue in the next phase then it would be a very difficult decision for us to continue on our own," said John Elbon, CST-100 programme manager, "and most likely we would not."
"The foundation of our business case is transporting NASA astronauts to the space station, and if that's the only part of the business that comes to be, that would be ok," said Elbon. "Certainly our business case is much more attractive if there's additional business beyond that."
NASA's direct support through CCDev is not the only avenue. CCDev remains wholly disconnected from a widely anticipated request for proposals for resupply flights to the International Space Station - or wherever else NASA decides to fly (manned landings on Mars or an asteroid are frequently discussed).
Yet CCDev money gives the recipients a massive head start against non-funded rivals, and while few companies have given up completely after failing to win a CCDev award, the near future almost certainly belongs to the winners.
Publicly traded Boeing is the exception among CCDev awardees. Blue Origin, Sierra Nevada and SpaceX are privately owned companies and thus under no particular obligation to earn profit to translate into shareholder dividends.
SpaceX founder Elon Musk has maintained that, while profit would be nice, his primary goal is to hurl things into orbit as cheaply as possible.
Late in April, Blue Origin programme manager Rob Myerson made it clear that he expects its spacecraft to fly, NASA or no. Sierra Nevada programme manager Mark Sirangelo could not confirm continued development without CCDev, but said: "NASA's a co-investor in the project, we're putting up a significant amount of our capital, and at the end of the day it's one of many markets we hope to service."
Additional NASA funding is sure to be at stake in future budget negotiations as the 2012 US presidential election nears.
NASA employees breathed a sign of relief when only a small portion of its budget was cut in the contentious continuing resolution that funds the government, over which a dramatic stand-off ensued.
But as the budget tightens and political battles loom, competitors for CCDev3 money will need to examine just how stable NASA is as an anchor customer and plan for the worst.