Weather, Technical And Logistics Problems, Could Prevent NASA From Finishing International Station By 2010 Deadline
NASA faces a daunting challenge in completing the International Space Station (ISS) by the October 2010 deadline for retirement of the space shuttle fleet, a Government Accountability Office (GAO) analyst warned Congress.
“NASA faces significant challenges in its plans to complete assembly of the International Space Station (ISS) prior to the scheduled retirement of the space shuttle in 2010,” Christina T. Chaplain, GAO director of acquisition and sourcing management, told the House Science and Technology Committee space and aeronautics subcommittee.
She said that since last summer, “the shuttle flight schedule has remained aggressive — slating the same number of launches in a shorter period.”
She is concerned that delays or unforeseen circumstances could prevent NASA from flying the remaining space shuttle missions needed to complete construction on the space station. That was a reference to the loss of years after Space Shuttle Columbia and its crew of seven were immolated during reentry in 2003, and NASA had to determine the cause and devise solutions while the shuttle fleet remained grounded.
Chaplain said, “While NASA thinks the proposed schedule [of space shuttle missions to finish the space station] is still achievable, the schedule:
- is only slightly less demanding than it was prior to the Columbia disaster when the agency launched a shuttle every other month with a larger shuttle fleet and
- leaves little room for the kinds of weather-related, technical, and logistical problems that have delayed flights in the past.”
Only three space shuttles remain to complete the task. And shuttle missions have been delayed for as much as months by bad weather, by faulty fuel sensor gauge data lines, by concerns over foam insulation that can rip off the external fuel tank and damage the orbiter vehicle (as occurred with Columbia), and more.
Future glitches could mean the space station won’t be completed, she warned.
“Unanticipated delays could result in changes to the station’s configuration, that is, some components may not be delivered,” Chaplain said. “We have previously testified that such changes could limit the extent of scientific research that can be conducted on board the ISS.”
She stressed that continued, timely completion of all space shuttle missions is critical, because only the shuttles have the bulk and brawn needed to haul huge ISS structural components into orbit for attachment to the growing space station.
“After assembly is completed and the shuttle retires, NASA’s ability to rotate crew and supply the ISS will be impaired because of the absence of a [shuttle] vehicle capable of carrying the 114,199 pounds of additional supplies and spares needed to sustain the station until its planned retirement in 2016,” she said.
From October 2010, when the shuttle fleet is retired, to 2015 when the next-generation Orion-Ares spaceship rises on its first manned mission, the United States won’t have a spaceship, and astronauts will have to be taxied to space by other nations or private commercial spaceships.
Chaplain noted that during the half-decade-long gap, NASA will have to rely on Russian, European and Japanese spaceships to take American astronauts and resupply cargo to the space station. But those far smaller ships are poor substitutes for the gigantic space shuttle.
“These [foreign] vehicles were designed to augment the capabilities of the shuttle, not replace them, and have far less capacity to haul cargo,” she noted. “Furthermore, aside from a single Russian vehicle that can bring back [a puny] 132 pounds of cargo, no vehicle can return cargo from the ISS after the shuttle is retired.”
The United States also aims to use private commercial spaceships to take cargo, and eventually astronauts, to space.
“NASA has pledged approximately $500 million for the development of commercial vehicles,” Chaplain observed. “NASA expects these vehicles will be ready for cargo use in 2010 and crew use in 2012, even though none of the vehicles currently under development has been launched into orbit yet and their aggressive development schedule leaves little room for the unexpected.” (Please see separate story in this issue.)
With no room for the unforeseen, “If one of these vehicles cannot be delivered according to NASA’s current expectations, NASA will have to rely on Russian vehicles to maintain U.S. crew presence on the ISS until the new generation of U.S. spacecraft becomes available” in the next decade, she noted.
It isn’t a pleasant prospect for leaders of the U.S. space program, and Chaplain said they are “well aware of the predicament [NASA] faces with the station and has weighed options and trade-offs for the remainder of the schedule manifest,” advising the space agency leaders to be poised to respond to the unexpected with flextibility.
NASA Administrator Michael Griffin has observed that it is “unseemly” for the nation that placed men on the moon to have no space transport capability for half a decade.
At the same time, he has taken a different view from Chaplain’s outlook, saying that NASA has a good chance of flying the remaining space shuttle missions on the current manifest. Griffin has stated that the manifest workload averages about four shuttle missions per year, less than the peak pace of pre-Columbia missions.
Chaplain estimated the cost of building the space station at $31 billion, and the cost of operating it at $11 billion through its planned retirement in 2016, for a total of $42 billion. But other estimates in the hearing pegged the total tally around $100 billion. (Please see separate story in this issue for details on space station retirement debate.)
To view the report titled “NASA: Challenges in Completing and Sustaining the International Space Station” in entirety, please go to http://www.gao.gov on the Web and click on report GAO 08-581T.