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Several false starts and nearly $400 million in taxpayer funds later, a California space company is aiming in a matter of days to be the first private firm to send its own capsule to the International Space Station.

The launch, set for this weekend, comes with high stakes, though -- as some begin to question NASA's drawn-out effort to fund private companies to eventually take over for the Russians in school-bussing American astronauts to the space hub.

For SpaceX, the company behind the launch, a successful mission could reinvigorate faith in the program. It would mark one of those "giant leaps" that the American space program is famous for.

But failure could fuel skepticism among critics looking for their "I told you so" moment. One former astronaut warned that some in Congress could spin this as a "Solyndra-like waste of taxpayer money" if things go poorly.

"It's such a high-profile launch that a failure could set not only the company back, but set NASA's policy back and call it into question," Tom Jones, who is now a space industry consultant, told FoxNews.com. "There's going to be fingerpointing if there's failure in this by political opponents of the White House saying, 'We told you so.'"

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The current program is a product of both Obama and George W. Bush administration policies. NASA first started investing in private companies to take over cargo missions to the space station in 2006. But when the shuttle was retired as scheduled under the Obama administration, it really gave the floor to the commercial space industry -- kicking the responsibility to the private sector to develop the technology to not only ferry cargo but astronauts into space.

With that decision, meant to save taxpayer money, came a tradeoff -- a substantial gap in U.S. access, leaving America to rely on other countries, like Russia, to carry astronauts to the station until the U.S. private sector is up to speed.

The unmanned SpaceX launch set for Saturday is for cargo only, not crew. It's tied to a NASA contract worth up to $1.6 billion to fly a dozen cargo missions to the station. One other company, Orbital Sciences, has a similar NASA cargo contract.

SpaceX, which has received $381 million to date for cargo mission development alone, is optimistic but stresses that success is not guaranteed during the launch. The company receives funding based on completing certain milestones and so far has hit 37 out of 40 of them.

"It is a very important mission for us -- it's very difficult, and it's the product of a lot of work," SpaceX spokeswoman Kirstin Brost Grantham said. "If it fails, we'll learn from this mission and we'll be ready to make another attempt in the next months."

But if it succeeds, she said, the company can proceed with its NASA contract and start transporting cargo to space more cheaply than it would be with other rockets. She said SpaceX is already preparing for the first official cargo mission. "The rocket for the next mission is already in Florida, undergoing tests," she said.

In the higher-stakes space race, SpaceX also is competing with several other big firms to be NASA's choice to bring astronauts into space. The competition for that honor includes Boeing, Blue Origin and Sierra Nevada, with NASA providing money along the way.

It's this entire strategy that has come under scrutiny in Washington.

Though the Senate has not followed suit, a House-approved budget bill directed NASA to basically wrap up the commercial crew competition and pick one finalist -- and potentially a backup, just to be safe.

The accompanying House Appropriations Committee report cited a litany of concerns with the commercial crew program -- that the government is "seeding" private space firms with its limited resources, that the overall $4.9 billion in estimated development costs is simply too high, and that the program has "insufficient safeguards" to protect intellectual property developed with federal money. The report raised the tale of Solyndra, the government-backed solar panel firm that went bankrupt, as a warning sign.

"There is a risk of repeating the government's experience from last year's bankruptcy of the solar energy firm Solyndra, in which the failure of a high risk, government subsidized development venture left taxpayers with no tangible benefit in exchange for their substantial investment," the report said, urging NASA to save money by picking the "most promising contender" now.

Some big-time former astronauts who have been loyal critics of the commercial approach heralded the move. In a recent letter to Rep. Frank Wolf, R-Va., chairman of the panel that wrote the NASA budget bill, Neil Armstrong and two other former astronauts cited the budget constraints on NASA and urged Congress to "maximize return on the limited funds available" by picking a finalist soon.

The ex-astronauts said the U.S. had "painted itself into a corner" by scrapping the shuttle and depriving itself of access to the space station.

The private sector program still has plenty of defenders on both sides of the aisle on Capitol Hill, including California Rep. Kevin McCarthy, the majority whip, who represents a district near where SpaceX is based.

Michael Lopez-Alegria, a former astronaut and current president of the Commercial Spaceflight Federation, acknowledged there's a lot at stake this weekend -- presuming the launch goes on as scheduled.

"There are a lot of eyes watching this," he said.

But Lopez-Alegria argued it's unfair to read too much into the launch if it goes poorly. He stressed that SpaceX is just one company, and that one launch does not represent the entire industry.

He urged Washington to keep the competition going, and not cut it short as some are advocating.

"Competition is good," he said. He argued that NASA needs to be dealing with multiple companies in order, among other reasons, to have a fallback.

NASA is casting the upcoming launch as just another stage in a longer process. A preview of the launch on the NASA website said that "if problems develop on this particular mission, NASA officials say the agency will keep the effort going and work to resolve any issues."

NASA called the mission, by itself, a "landmark" and said successful docking would give the company another "place in the record books."

Jones, for his part, urged NASA to cut the contest short and pick a winner as soon as possible, for the sake of time. "I would not wait five years to pick a winner. I would want these guys flying within two or three years," he said.

Jones recalled grumbling in the space industry a couple years back, when the commercial competition really started to take off and SpaceX emerged as a major player. The founder of that company -- Elon Musk, who is also behind electric car company Tesla -- is a prolific political contributor to Democrats and Republicans, a fact Jones said had some claiming SpaceX had an "inside track" on commercial flight funding early on.

But Jones said he has no dog in this fight, and that SpaceX probably has justified its place in the competition.

SpaceX, after all, was the first company to launch a capsule into orbit and recover it.

Grantham said any claim that SpaceX was aided by Musk's political connections is "ridiculous."

"SpaceX has won support from NASA and a wide variety of commercial customers because we are providing the best proposals, because we have a demonstrated track record of success," she said. "I think our success speaks for itself. "

The upcoming launch of the so-called Dragon spacecraft, which has been delayed several times since last year, takes the next big step. The list of tasks is daunting.

SpaceX is trying to not only deliver cargo to the International Space Station, but perform a series of other demonstrations and eventually try and dock it.

Lopez-Alegria said he's "optimistic" about the launch, though he stressed that SpaceX is squeezing multiple missions into one with its lengthy itinerary.

"To get it all done would be hitting it out of the park," he said.

FoxNews.com's Jeremy Kaplan contributed to this report.