WASHINGTON — U.S. lawmakers continue to pressure NASA to honor its commitment to launch a particle physics experiment to the international space station aboard one of the few remaining space shuttle missions.
Sen. Bill Nelson (D-Fla.), chairman of the Senate Commerce space and aeronautics subcommittee, devoted part of a recent budget hearing to making very specific suggestions about how NASA could shoehorn the 6,750-kilogram science payload, known as the Alpha Magnetic Spectrometer (AMS), onto one of the space shuttle’s 12 remaining flights.
The AMS is designed to be mounted to the outside of the international space station. Led by Nobel laureate Samuel Ting at the Massachusetts Institute of Technology, some 16 nations have spent a combined $1.5 billion building the AMS, making it one of the most expensive scientific experiments of all time. NASA committed in 1995 to delivering the AMS to the station.
But that was long before the 2003 Space Shuttle Columbia accident and the United States’ subsequent decision to retire its orbiter fleet from service in 2010.
NASA Administrator Mike Griffin says there is no room for the AMS on any of the remaining shuttle flights and that he lacks the authority and budget to add a flight to the manifest. “If I had that authority I would have added the shuttle flight and we would not be having this discussion,” Griffin told House lawmakers in mid February.
Two weeks later, at the Senate Commerce space and aeronautics subcommittee’s Feb. 27 hearing, Griffin was again getting pressured to recommit to flying AMS. Only this time, the focus was on fitting AMS onto an existing flight rather than adding a mission to the manifest.
Nelson, the only current member of Congress to have flown on the shuttle, suggested NASA offload cargo from one of three logistics missions planned for 2009 and 2010 and send it up instead on new vehicles Orbital Sciences Corp. and Space Exploration Technologies are developing under the Commercial Orbital Transportation Services (COTS) program.
“Sir, we’ve looked at that over and over again. The payloads that are manifested on the shuttle now until its retirement are either crucial to the assembly or they are crucial for maintenance of the station during the gap,” Griffin said, referring to the projected five-year period between retiring the shuttle and fielding its successor, the Orion Crew Exploration Vehicle and its Ares 1 launcher.
“In our judgment the cruciality of sustaining the space station appropriately with the tens of billions of dollars we have invested in that outweighs the desire to fly the AMS,” Griffin continued. “It’s not that I don’t wish to fly the AMS, it’s that I have to put the [international space station] at risk to do it. And I don’t have other good means to get the hardware up to the station that I need to have there. I do not have the authority to add another shuttle flight to the manifest, so I am out of options. I’m out of options.”
“I don’t think you are out of options,” Nelson shot back. “You have some very smart people who work for you throughout this NASA network we know as the NASA family. And what some of these smart people have suggested is that unpressurized logistics flights … could be launched after the AMS [is] launched [using] 25 percent of the cargo bay.”
Nelson identified three shuttle logistics flights that could be replanned to make room for AMS: STS-129 in August 2009; STS-131 in February 2010; and STS-133 – the shuttle’s final flight – planned for July 2010.
Each of those three missions currently are slated to carry up two Express Logistics Carriers loaded with spare parts – also known as orbital replacement units, or ORUs for short – that would be stored on the outside of the station until needed.
Griffin was not pleased by Nelson’s suggestion that NASA personnel or agency contractors had been freelancing the AMS issue.
“I think some of my people may be stepping a bit out of line,” Griffin said, before refuting Nelson’s premise that AMS would take up only a fourth of a shuttle cargo bay.
“When you talk about 25 percent of a cargo bay, you’re talking about by volume. And yes, AMS uses 25 percent of a cargo bay by volume. It uses almost half of a cargo bay by weight,” Griffin said. “I can’t displace 25 percent by volume of ORUs and replace it with AMS because I have to actually account for the weight as well as the volume.”
Griffin, however, agreed to have NASA take another look at the possibility.
“The manifesting challenges for what’s on the space shuttle today are not trivial and everything that is on there is on there as a result of a very severe winnowing process,” he said. “But I understand your question and I will not be cavalier with it. I will take it for the record and we will give you a detailed answer as to how we might manifest these other things, if it is possible, on other flights. But we have looked at that.”
“Well, I’m sure you have,” Nelson said. “But again, this is coming from your very smart people. Let that ingenuity bubble up. Let that creativity bubble up.”