Space debris, sudden illness and even errant commands from Houston could jeopardize the International Space Station's mission, but back-up plans and equipment have most of the threats covered, according to a report released on Tuesday.
The report to Congress finds a 55 percent chance that some sort of space debris could penetrate the space station, home to three crew members, and a 9 percent chance of a "catastrophic result over a 10-year period," NASA said in the report.
"This risk can be reduced to 29 percent and 5 percent respectively by implementation of changes that are available or being considered for development," it adds.
Another big problem — a lack of money and the planned shutdown of the space shuttle program in 2010 according to the report, written by an independent panel of consultants, NASA scientists and aerospace engineers.
"If productive operations cannot be restored through other cargo delivery means, the Station might have to be abandoned before NASA can complete its research objectives and obligations," the report reads.
"Based on the projected shortfalls and the current projected costs of logistic launch services, NASA will require an additional $1 billion per year to procure the necessary additional launch services. "
The full report is available on the Internet at http://www.nasa.gov/mission_pages/station/news/index.html.
The report is "something we are looking at and have been for some time," said NASA spokesman Allard Beutel. "A lot of these things have been on our radar for some time."
The space station, a joint effort by United States, Russia, Canada, the members of the European Space Agency and Japan, orbits about 215 nautical miles (400 km) above the Earth. U.S. space shuttle missions and missions by the Russian space agency are steadily adding to the station, resupplying it and bringing crew back and forth.
Congress asked NASA to report on all potential threats that could cause the abandonment or destruction of the space station, meant to be an orbiting base, jump-off point for other human space missions and a way to practice living in space.
The main problem is space junk and natural debris, according to the report. At the speeds achieved in space, even a tiny rock or piece of metal could pierce the outside of the space station, and if the hole is big enough or in the wrong place, the result could be disastrous. Adding shielding could help defray these risks.
The report also points to illness as another risk to the space station.
"In a worst-case scenario, a spontaneous health event may necessitate returning the crew to Earth for specialized medical attention, which would result in temporary abandonment of the ISS," the report reads.
It says based on experience with people living in other remote places such as submarines or Antarctica, a medical emergency requiring medical evacuation might occur once every four to six years.
Other possible disasters include:
- A collision by a visiting vehicle or robotic arm
- An on-board fire
- A toxic spill
- A catastrophic system failure
- A hardware or software design flaw
- The loss of a crew member during a spacewalk
- A deliberate attack using false commands from the ground
- A mistaken command from the Mission Control Center.