They'll stow an old ammonia tank in the Shuttle's payload bay and remove and replace a couple of shields that help protect against space debris.Î¾
Astronauts are technically off-duty today and are helping NASA celebrate a big day in the agency's history.Î¾ It's been 29 years since the first shuttle launch. Columbia blasted off on this day in 1981.
Today also marks the first person in space. Russian Cosmonaut Yuri Gagarin headed into space in 1961.