A climate of uncertainty in the US space program combined with the approaching retirement of the shuttle missions presents safety risks, a government advisory panel said Thursday.
"Lack of clarity and constancy of purpose among NASA, Congress, and the White House is a key safety concern," the Aerospace Safety Advisory Panel said in its annual report.
"From the aspect of safety, the lack of a defined mission can negatively affect workforce morale and the ability to attract and maintain the necessary skill sets needed for this high-technology venture," it said.
The report came on the heels of news that NASA was bickering with US senators over plans to build a new spacecraft and rocket to replace the shuttle mission by 2016.
The US space agency says the current vision for a new rocket and spacecraft would be too complicated to finish in the time constraints set forth by Congress, and too expensive given the budget it is allocated.
Meanwhile, the safety panel noted that once the shuttle fleet retires later this year, the United States, Europe, Japan will be dependent on Russian Soyuz vehicles for transport to the International Space Station.
While it did not criticize the safety record of the Russian space program, the panel said that because only one form of transport is available, risks will inherently increase.
"Any time one depends on a single-source solution, one runs the added risk of interruption in service due to some unforeseen contingency affecting that source," it said.
"We have no evidence that Progress and Soyuz will be anything but as reliable as they have been; however, risk rises as the simple offshoot of dependence on a single-source provider."
The panel said it would continue to study "the risks inherent in this single-source service scenario" over the coming year.
Plans to get a commercial spacecraft in operation to replace the US shuttle flights are about a year behind schedule, it said.
The advisory group also urged NASA, Congress and the White House to "quickly reach a consensus position on the agency's future and our nation's future in space."
The report noted that President Barack Obama has signed a bill "that reoriented the Agency's human spaceflight efforts; however, NASA's future human exploration mission plans are uncertain."
The panel was first established by Congress in 1968 after a deadly fire killed three astronauts on the Apollo I during a launch pad test.
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