STS-128: Spacewalk in progress

Preparing to lock down the ammonia tank in Discovery's cargo bay.

As I write this the astronauts are removing the ISS Ammonia Tank Assembly from the External Truss for storage in the Discovery's Cargo Bay. Danny Olivas and Nicole Stott (Expedition 20 ISS member) have been out there for a bit over 4 hours now.

They make it look so easy, but it's the result of countless hours of practice and preparation. With the effects of Zero-G, the tank appears to move so effortlessly, yet we have to remember that mass still matters in space. Moving mass has momentum, and unchecked careless maneuvers could result in smashed bodies and torn spacesuits. There is nothing easy in space. But it is all worth it.

Along with the used ammonia tank, the astronauts will recover several exposed experiments and store them in the cargo bay as well.