Station Fires Engines to Avoid Orbital Debris

ISS Status Report

At 10:36 p.m. EDT Friday, ground controllers moved the International Space Station away from a piece of orbital debris. The object is a relic from a collision between the COSMOS 2251 and Iridium 33 satellites in February 2009 and had been close to the station’s orbit prior to the debris avoidance maneuver (DAM).

The DAM, performed during the Expedition 27 crew sleep period, used thrusters from three spacecraft, the European Space Agency’s Johannes Kepler Automated Transfer Vehicle 2 (ATV2), the Zvezda service module and Progress 41P.

Mission Control Center had been monitoring a series of conjunctions between the International Space Station and the orbital debris. The Expedition 27 crew was informed of the possible conjunction and planned maneuver.

While the Mission Control Center planned the debris avoidance maneuver, the three-member Expedition 27 crew continued preparing for the upcoming arrival of three more crew members on Soyuz 26 following Monday’s launch of NASA astronaut Ron Garan, and Russian cosmonauts Andrey Borisenko, and Alexander Samokutyaev from the Baikonur Cosmodrome in Kazakhstan, and for the upcoming STS-134 mission of space shuttle Endeavour.

The maneuver is not expected to significantly affect the launch time for the Soyuz TMA-21 on April 4 at 6:18 p.m. EDT, or the April 19 launch of Endeavour.

Expedition 27 Flight Engineer Paolo Nespoli worked in the International Space Station’s Quest airlock Friday, checking out one of the Simplified Aid for EVA Rescue (SAFER) systems that will be used during STS-134. Essentially a "life jacket" for spacewalks, SAFER is a self-contained maneuvering unit that is worn like a backpack. The system relies on small nitrogen-jet thrusters that can be used should an astronaut somehow drift away from the complex.

Nespoli also configured other spacewalk tools, including cameras, tethers and equipment bags.

Astronaut Cady Coleman, also a flight engineer, continued working with the Nanoskeleton experiment, which looks at the effect of gravity on oil flotation, sedimentation and convection on crystals generated in microgravity. This could aid in the development of lighter, stronger materials.

She also worked with Nespoli in preparing the Quest airlock for the upcoming spacewalks.

Commander Dmitry Kondratyev performed some routine maintenance removing and replacing dust filters in the Poisk module and testing software on one of the stations laptops.

At the Baikonur Cosmodrome in Kazakhstan, Garan , Borisenko and Samokutyaev continued preparations for their journey to the orbital complex where they will join the Expedition 27 crew as flight engineers. Their Soyuz TMA-21 spacecraft, named for Yuri Gagarin, is scheduled for liftoff on Monday (Tuesday, local time), just one week shy of the 50th anniversary of Gagarin's historic journey into space from that same launch pad at the Baikonur Cosmodrome.

Space shuttle Endeavour is slated to lift off on April 19 to begin the STS-134 mission. The orbiter will deliver the Alpha Magnetic Spectrometer and spare parts including two S-band communications antennas, a high-pressure gas tank, additional spare parts for the Dextre robotic manipulator and micrometeoroid debris shields. This will be the 36th shuttle mission to the International Space Station and the final flight for Endeavour.

N5VHO – Mon, 2011 – 04 – 04 07:10