This story was updated at 7:52 a.m. EDT.
As NASA?s 50th anniversary approaches, the agency finds itself at a crossroads between the waning era of the U.S. space shuttle and serious hurdles ahead to build a replacement spaceship while still keeping American astronauts flying.
The U.S. space agency turns 50 years old on Oct. 1 with the last flight of its three aging shuttles already set for May 31, 2010 aboard the orbiter Atlantis.
NASA officials in charge of the developing the shuttle?s replacement - the Orion Crew Exploration Vehicles and their Ares I boosters - hope to have the spaceship ready for manned flights by 2014, though unless Congress steps in soon American astronauts will likely be grounded beginning in 2012 due to restrictions on NASA?s ability to buy seats aboard Russian spacecraft. Meanwhile, the agency is simultaneously taking an academic look at what?s needed to extend shuttle missions through 2015 to be ready for any questions from the new administration after November?s presidential election.
?It?s kind of a unique juncture of history that we are engaged in at this point in time with so many issues, and the tasks are pretty large and quite daunting,? said Roger Launius, a former NASA historian and senior curator with the Division of Space History at the Smithsonian Institution?s National Air and Space Museum in Washington, D.C. ?It?s time to move on.?
Shuttle to Orion
NASA?s has planned to retire its three shuttle fleet since 2004 under the Vision for Space Exploration, which includes bringing Orion and Ares I online by 2015 and sending astronauts back to the moon by 2020. The plan calls for Ares I rockets to launch Orion capsules to orbit on flights to the International Space Station or to link up with a lunar transfer stage and Altair moon lander lofted separately atop a planned Ares V heavy-lift booster.
Budget shortfalls and recent shuttle flight delays prompted NASA?s Constellation program to push back internal targets for test flying Ares and Orion crew vehicles, though officials hit a milestone earlier this month when an engineering panel signed off on the preliminary design for Ares I rockets.
?You?re always going to find out that there are things you don?t know, which can be fixed. So figuring out and fixing them is what we do,? NASA Administrator Mike Griffin said in a televised agency-wide update on Sept. 12. ?Ares and Orion are going very well for development projects on a scale that the agency has not tackled for decades.?
The agency had hoped to launch the first Ares I test - dubbed Ares I-X - from the Kennedy Space Center in Florida by April 15, 2009, under a plan to begin manned flight tests as early as 2013. But delays to the next shuttle flight - Atlantis? STS-125 mission to overhaul the Hubble Space Telescope - pushed the Ares I-X test flight to no earlier than next June because NASA must hold the Ares pad in reserve for a second shuttle, which is serving as a rescue ship in case of an emergency.
The Hubble flight is slated to lift off Oct. 10, after being pushed from an earlier August launch date due to fuel tank delays.
Funding constraints, meanwhile, have hindered design review plans for the Orion Crew Exploration Vehicle. NASA is currently spending about $3 billion per year through 2010 on Orion and Ares I, but could have been farther along if additional funds were available, program managers said.
?We needed about $1 billion for each of the next two years to really put us on the glide path to make that a high confidence plan,? said John Hanley, manager of NASA?s Constellation program overseeing Ares and Orion development, of the 2013 target in a Sept. 10 briefing. ?When that didn?t materialize, we of course had to adjust our schedule in order to allow the work to fit the money, and that?s what we?ve done.?
New spaceship hurdles
Challenges in developing any new human spaceflight system are to be expected, and NASA?s Orion and Ares have their fair share.
?I think they?re obviously making progress toward fielding a new vehicle, but they do have enormous technical challenges,? Launius said of NASA, adding that the U.S. has not designed a manned spacecraft from scratch since the birth of the shuttle fleet in the early 1970s. ?We basically do this once a generation and we?re now at that point where we?re doing it.?
The current Ares I design, a two-stage rocket that uses a five-segment version of the space shuttle?s solid rocket booster as a first stage, shakes too much. Engineers have come up with a novel shock absorber plan to mitigate the excessive vibration.
Design teams have also been dogged by the Orion capsule?s weight, which they have been working to slim down for extra launch margin since the spacecraft will be used for rides to the International Space Station and planned long duration treks to the moon. The design review process for that component has been delayed to some time next year.
Early work is underway to modify the Ares I rocket?s launch pad at the Kennedy Space Center to ward off lightning and other hazards. Meanwhile, Ares I engineers are tackling time-consuming, but not insurmountable problems like smoothing out the rocket?s stage separation and deciding to safeguard the booster to fly through rain, hail or direct lightning strikes, said Ares project manager Steve Cook.
?We?ve certainly got design challenges ahead, but if we didn?t have challenges we wouldn?t need engineers,? he added.
American access to orbit
While engineers tackle plans for Orion and Ares, NASA has already set the last flights for each of its three remaining space shuttles - Atlantis, Discovery and Endeavour.
Under the current schedule, Atlantis would launch its last flight, STS-131, to the space station on Feb. 11, 2010. Discovery and Endeavour would follow, lifting off on April 8 and May 31 of that year, respectively.
NASA had hoped to rely on Russian Soyuz spacecraft to launch American and partner astronauts to the International Space Station between the shuttles? retirement the first manned Orion flights.
But unless Congress extends the agency?s exemption from part of the Iran-North Korea-Syria Non-proliferation Act (INKSNA) by year?s end, American and NASA partner astronauts will miss at least one of the space station crew rotation flights in 2012. Russia?s recent military conflict with neighboring state Georgia in early August has cast a pall over the waiver talks.
?I?ve been putting every bit of political capital that I might have or can borrow behind securing an extension of that wavier until we can get Ares and Orion flying,? Griffin said last week. ?But it?s tough and the Hill is not of one mind on that subject.?
Some supporters include Sen. Bill Nelson (D.-Fla.), who has been advocating a waiver extension for astronaut seats, but has urged NASA to commit to U.S. commercial launch services for station cargo. Others, like Rep. Dave Weldon (R-Fla.), believe relying solely on Russia for U.S. access to space to be a grave misstep.
?Laying off thousands of experienced space program workers and relying on Russia to get the U.S. into space was a bad idea then, and it is even a worse idea now,? Weldon said in a Sept. 12 statement. ?By granting the Russians a waiver, as he now advocates, we will guarantee thousands of pink slips to workers at KSC. Russia continues to sell dangerous technologies directly related to weapons of mass destruction to Iran, defies sovereign rights in Georgia, and threatens Poland with intervention.?
Also clouding the issue is the upcoming presidential election, which has prompted NASA to take a second look at what steps would be required to extend its space shuttle flights through 2015 in order to answer any questions from the new administration.
Last month, Republican presidential candidate John McCain (R-Ariz.) and other senators sent a letter to President George W. Bush beseeching his administration from instituting any policies that would prevent U.S. shuttles from flying beyond 2010. Democratic presidential candidate Barack Obama (D-Ill.), too, has pledged to continue the Constellation program and has said in the past that extra space shuttle flights might be an option.
Griffin has said that the odds of a loss of vehicle or crew failure during shuttle mission will increase dramatically if the program is extended to fill the gap between orbiter retirement and Orion operations in 2015. Adding two shuttle flights per year would shift the odds from a 1-in-80 chance of a failure to 1-in-8 flights.
?That?s the facts. That?s where we are,? Griffin said this month. ?I?d rather work toward spending our money toward building a safer system.?
And while NASA has begun terminating some of its contracts that support space shuttle missions, there is some flexibility as to what it might be able to do if directed by the new administration. John Shannon, NASA?s space shuttle program manager, said earlier this month that while extending shuttle flights through 2015 may not delay plans for Ares I launches, it would likely delay Ares V rocket development that would support new manned missions to the moon.
?We have been aggressively retiring thing that we do not need for the space shuttle program,? Shannon said. ?But we haven?t reached the point of no return.?
- NASA?s Space Shuttle: The Final Missions
- Video - NASA's Constellation Journey Begins: Part 1, Part 2
- Video - Back to the Moon with NASA's Constellation