NASA extends STS-117 to repair thermal blanket

William Atkins
Wednesday, 13 June 2007 00:43

Science - Space

According to NASA engineers, a flap with dimensions of approximately 4 inches by 6 inches (10 centimeters by 15 centimeters) was forced out of position due to aerodynamic pressures during the ascent of the Space Shuttle Atlantis during the launch phase on Friday, June 8, 2007.

The damaged heat-resistant thermal blanket is not a life-threatening problem for the astronauts as they de-orbit from space and re-enter through the Earth’s atmosphere. The 24-square-inch break in the blanket is not a serious flight risk because temperatures at that location—on the left Orbital Maneuvering System (OMS) pod of Atlantis, which is on the top side of the Shuttle—normally reach only 600 to 700 degrees Fahrenheit.

Such temperatures on the top side of the Shuttle are not nearly as hot as the Shuttle’s underbelly (underside), whose temperatures can reach 3,000 degrees Fahrenheit during descent into the Earth’s atmosphere. The underside of the Shuttle contains black heat-resistant tiles and carbon composite panels that are able to resist the higher temperatures experienced during flight into the Earth’s atmosphere in preparation for landing back at the Kennedy Space Center.

However, members of NASA’s STS-117 Mission Management Team are worried that if left as is, the break in the blanket could allow heat inside the OMS pod and damage the graphite-epoxy structure. Such damage, NASA contends, might delay the rest of the year’s three flights, which NASA would rather not do.

NASA officials are now conferring as to whether to repair the thermal blanket during the planned third spacewalk or to do the task during a newly created fourth spacewalk. In either case, the astronaut tagged to repair the blanket will attach himself to the Canadian-built robotic arm and boom in order to be transported to the repair site.

While repairing the thermal blanket, the pair of spacewalking astronauts will also perform several get-ahead tasks while outside of the Space Station. “Get-ahead” tasks are tasks reserved when extra time is available after the accomplishment of all the regularly assigned jobs.

With this two-day extension, the STS-117 crew, along with new crewmember Sunita Williams, is scheduled to land on June 21, 2007, at about 1:54 p.m. EDT (17:54 GMT), after their 13-day mission to make further additions to the International Space Station.