WASHINGTON — NASA
is turning to private space companies to plug a worrisome five-year gap
in its ability to boost astronauts into orbit and return them safely to
Earth.

The gap runs from the end of next year, when the three
remaining space shuttles are supposed to be retired, until 2015, the
earliest that NASA’s slow-moving replacement system, called Constellation, will be ready to do the job.

After
the shuttle’s retirement, the U.S. will have to rely on Russia to ferry
Americans to and from the International Space Station, where six crew
members from five nations are now circling the Earth.

This situation frustrates and embarrasses NASA and annoys lawmakers, who fear citizens will wonder why the U.S. has to depend on its old Cold War rival for rides into space.

As
a result, two private companies are being asked first to demonstrate
their ability to deliver cargo — food, water, equipment and supplies —
to the space station starting in 2011. Commercial launches of human
crews, a much riskier operation, would come no sooner than 2012, if at
all.

There will be “a significant gap” in our ability to get
cargo and people into orbit, Michael Suffredini, ISS program manager,
told a high-level “Review of U.S. Human Space Flight Plans Committee”
last week.

The committee, headed by Norman Augustine, the retired chief executive of the space-military contractor Lockheed Martin, was created by the Obama administration to evaluate NASA’s
plan to send humans to the moon and eventually to Mars. It’s supposed
to make its recommendations — to continue, alter or scrap the project —
by the end of August.

“We believe we can eliminate the gap,” Elon
Musk, chief executive of Space Exploration Technologies — SpaceX for
short — of Hawthorne, Calif., told the Augustine committee. “We can
provide housekeeping and logistical services,” he said. “We’ll let NASA concentrate on the Moon and beyond.”

SpaceX and its chief rival, Orbital Sciences Corp. of Dulles, Va., received preliminary NASA
awards totaling $500 million in December. SpaceX’s contract calls for
it to make 12 cargo flights starting in March. Orbital is supposed to
launch eight cargo flights, beginning in March 2011. The contract’s
total cost will be $3.5 billion.

“Cargo doesn’t seem glamorous,
but we need it to keep America flying in space,” Frank Culbertson,
Orbital’s senior vice president for human space flight, told the
committee.

Skeptics are concerned about the ability of private companies to meet NASA’s
safety and reliability standards. SpaceX’s Falcon 1 rocket failed three
times before it finally managed to put a small, dummy payload in orbit
last September. Orbital lost a Taurus rocket, carrying NASA’s Orbiting Carbon Observatory, in February.

“Despite
their best efforts, some truly private enterprises have not been able
to deliver on plans of launching vehicles,” Sen Richard Shelby, R-Ala.,
told a Senate hearing in May. “However grandiose the claims of
proponents (for commercial space flights) are, they cannot substitute
for the painful truth of failed performance at present,” Shelby said.

Another
question is whether it’s worth the cost and risks to keep the $100
billion space station operating after its original life expectancy runs
out in 2015 — a decision the Obama administration hasn’t yet made. The
president’s science adviser, John Holdren, asked the Augustine
committee to review this issue too.

ISS international partners
want to preserve the station but fear that the U.S. will back out of
the project, probably dooming it.

Gen. Anatoly Permilov, the head
of the Russian Space Agency, told the committee that Russia wants to
extend the life of the space station “to 2020 at a minimum.”

“We
have to continue the ISS to reap the benefits,” said Jean-Jacques
Dordain, the director-general of the European Space Agency. “We’re just
at the end of the (station’s) assembly period. We’re just starting the
utilization period.”

“If NASA withdraws, that would be the end of the ISS,” Dourdain said.