CAPE CANAVERAL, Florida -- With just five space shuttle flights remaining, the program that has come to symbolize U.S. space superiority for the last 30 years is coming to an end, with no replacement on the near horizon.
The Obama administration is considering whether it should go ahead with efforts to further explore the moon and Mars -- a plan initiated by the previous administration in 2005 -- or scale back and stay closer to Earth.
The shuttle "Atlantis," carrying six American astronauts, sailed smoothly into orbit on November 16, carrying 15 tons of equipment for the orbiting International Space Station (ISS).
NASA's prototype Ares 1 rocket rolls out to the launch pad on October 20.
Astronauts are now gearing up for a second spacewalk on November 23, following a successful six-hour operation outside the ISS on November 21.
Over the program's nearly three decades -- the first shuttle flew in April 1981 -- the five reusable orbiters (three remain in active service) and their crews have deployed satellites, observatories, and planetary probes. They delivered, and repaired, the orbiting Hubble Space Telescope, visited the old Russian Mir space station, and transported crucial elements of the International Space Station.
The program has been a remarkable scientific and human achievement, but one that has come at a cost -- the explosion of the "Challenger" shuttle during takeoff in January 1986 and the destruction of the "Columbia" orbiter on reentry in February 2003. Fourteen astronauts died in those two accidents. Difficult Choices
The shuttle program became the cornerstone of the U.S. space program after the end of the "Apollo" lunar missions in the late 1960s and early '70s, but it is scheduled to end in 2010.
Kyle Herring, a spokesman for the U.S. space agency NASA, tells RFE/RL that the Obama administration now has difficult choices to make as it evaluates what to do next in space, and how to do it.
My biggest regret is that we haven't already built the successor to the shuttle.
"The president commissioned a group to study what direction NASA and the country should go in relative to, 'Do we go back to the moon first? Do we try to stage from the International Space Station, [or] do we want to go directly to Mars with a flight in 20 years or so?' " Herring says.
The so-called Augustine Report on the future of space travel, commissioned by NASA and released in October, concluded that human space travel to the moon and then Mars, as envisioned by the Bush administration, is unsustainable with NASA's current $18 billion budget.
For now, when there is no clarity on the future direction of space exploration, the only certainty, Herring says, is the continuation of the ISS.
"You just stay the course. Concentration obviously is on the International Space Station and the space shuttle program, to finish out the flights safely that we have remaining," he says.
NASA is intent on stocking the ISS with as much equipment as it can carry while there are still shuttles flying. When the shuttles are retired -- the last flight is scheduled for September 2010 -- the orbiting complex will have to rely on Russia's "Soyuz" rockets, at least until 2015.'Going To Be A Gap'
Wayne Hale, a program director for the space shuttle program, tells RFE/RL that it was clearly an oversight for the United States to have allowed at least a five-year gap between the last scheduled flight of the shuttle and the next generation of spacecraft, the two-stage Ares 1 rocket and Orion crew capsule. A prototype of the Ares 1 rocket was successfully launched by NASA last month.
"Atlantis" on the launch pad. The final shuttle flight is scheduled for September 2010. (photo by Nikola Krastev)
"My biggest regret is that we haven't already built the successor to the shuttle. The shuttle was supposed to last for 10 years; it's now going to last almost 30," Hale says. "We do have a plan to build a successor vehicle, but there is going to be a gap now of a few years before we have that built, between the time we retire the shuttle and the new vehicle is ready to go flying."
NASA officials hope to keep the ISS flying until 2015, or possibly as long as 2020.
After the shuttle fleet's retirement, Hale says, European and Japanese cargo ships will provide the station with food, fuel, and other supplies. But ISS crewmembers will have to fly there on Russian "Soyuz" capsules, which have proven to be the most reliable space vehicles of the last 40 years. Moscow is charging up to $50 million per seat.
"The Russian Federation's 'Soyuz' is going to be our mainstay for that time period," Hale says. "The Russian Federation has become a great space partner. We work closely together, as indeed we do with the European Space Agency, which is 17 nations in Europe that provide, for example, cargo capability."
NASA has plans to put U.S. astronauts back on the moon by 2020 and to eventually establish manned lunar bases for further exploration to Mars under a project called Constellation.
But the space agency's budget is currently too small to pay for Constellation. The Augustine Report concluded that NASA needs an additional $3 billion a year if it's going to meet its goals. Several options are being considered, including the participation of commercial enterprises.