SpaceX CEO Elon Musk (right) with Dragon V2 spacecraft. Boeing and SpaceX are expected to start routinely transporting crews to international space station next year. But the operation of such taxis is already years behind schedule. Photo: Reuters
The US space agency is working on a novel fallback plan in case new commercial vehicles hit further delays in their schedule to begin ferrying US astronauts into orbit.
Boeing Co. and Space Exploration Technologies Corp., known as SpaceX and founded by billionaire Elon Musk, are expected to start routinely transporting crews to the international space station next year.
But with the operation of commercial space taxis already years behind schedule due primarily to technical hurdles, and the latest deadlines in danger of slipping further, the National Aeronautics and Space Administration is considering Plan B: Turning scheduled test flights of new crew vehicles to the station into modified operational missions to ensure continuous US presence onboard the orbiting laboratory.
The potential move was disclosed Thursday, as part of various contingency options, by William Gerstenmaier, head of the agency’s human exploration programs.
Nasa currently has contracts to use Russian rockets and capsules to transport astronauts to and from the space station through late 2019. If Boeing and SpaceX aren’t ready to take over the job at that time, the agency will need a contingency plan to get crews to the station.
While Mr. Gerstenmaier said Boeing and SpaceX have made good progress on their respective crew vehicles, the shift to using American hardware is expected to take time and include “bumps in the road.” By making each of the planned test flights “almost an operational mission,” the agency would be able to plug potential gaps in space station staffing, he told an industry-government conference in Washington.
Boeing and SpaceX have previously said they are on track to complete one test flight with people on board by the end of this year, and Mr. Gerstenmaier said in an interview that the agency has “almost six months of margin on the schedules”—meaning they can be up to half a year behind deadline and still avoid a gap. Still, technical challenges and agency reviews could delay those plans.
Mr. Gerstenmaier said preliminary discussions have started inside Nasa, as well as with industry officials, about pushing the test flights into 2019 or later, as “part of normal contingency planning.” Regular missions are slated to commence after test flights are successfully finished.
The extent of potential test-flight slips will depend on “how late things are and how much of a gap we need to fill,” the veteran Nasa official said in the interview.
Nasa has several months to weigh alternative strategies, and Mr. Gerstenmaier stressed that no final decision had been made.
“In the worst case, we could potentially downsize” the number of US astronauts on board the space station as a temporary stopgap measure, Mr. Gerstenmaier told conference attendees. Such a move would reduce the amount of research conducted in orbit.
The latest comments underscore nagging questions inside and outside Nasa about the likely schedule for shifting crew transportation to US providers.
After fatal explosions of two space shuttles in 1986 and 2003, Nasa committed to making future spacecraft substantially safer than the shuttle fleet it was then operating. Yet as Nasa works to certify separate transport systems developed by contractors, agency experts are wrestling with challenging safety and schedule trade-offs.
In his speech, Mr. Gerstenmaier said his intention is to “openly talk about the risks” inherent in space travel and “not rush decisions” to meet arbitrary deadlines. “We need to accept risk and move forward,” he said. In the interview, he reiterated that risk assessments are imprecise and detailed statistical measures can vary significantly depending on assumptions.
Nasa has a longstanding requirement that commercial crew systems meet certain statistical safety benchmarks before ferrying astronauts. The agency has established that risk standard as no greater than one possible fatal accident in 270 flights. Although that still seems perilous, the standard reflects the technical hurdles confronting contractors. It is more than four times safer than the space shuttle fleet that was retired in 2011 under budgetary strains and safety concerns.
Nasa officials and the agency’s top independent safety watchdogs have repeatedly said it may be difficult to precisely comply with the new standard, in part because companies are having trouble finding ways to reduce cumulative exposure to radiation during typical trips to the space station and six-month stints for astronauts in orbit.
Even if the agency opts for some contingency plans, Mr. Gerstenmaier and his colleagues may have to issue certain safety waivers before commercial crew capsules can begin making regular trips.
Source: The Wall Street Journal