Shuttle Discovery's astronauts have one last spacewalk ahead of them. Two former schoolteachers — Joseph Acaba and Richard Arnold II — will venture outside the international space station this morning and take another crack at deploying a jammed equipment storage platform.
On Saturday, spacewalkers accidentally inserted a pin upside down on the platform. The catch for the mechanism also proved to be unusually stiff.
This time, Acaba and Arnold will use all their strength to get the platform deployed properly. They will have pry bars and hammers with them, just in case. If all else fails, they will tie the platform down with sturdy tethers to keep it from banging around.
A hastily assembled team of experts spent Saturday night and much of Sunday trying to figure out how best to deal with the problem. The astronauts, meanwhile, gathered up a pry bar, a couple hammers and other tools to force the pin loose, if ordered to do so.
The storage platform — located on the long space station framework that holds all the solar wings — is meant to secure big spare parts that will be needed once NASA's shuttles stop flying. Because of all the pin trouble Saturday, the astronauts did not have time to deploy additional shelving on the opposite side of the station. That work was bumped to Monday's spacewalk.
Tethers are holding down the jammed platform so it won't bang around, but they're certified for only three months out in the vacuum of space. Mission Control asked the crew to collect stronger tethers to better secure the platform in case it remains stuck.