Soyuz TMA-08M to Make First Direct Ascent to ISS

The next International Space Station (ISS) crew is scheduled to launch in their Soyuz TMA-08M spacecraft in the afternoon of March 28, 2013 Eastern Daylight Time (EDT). This will be the first ISS crew to make a direct ascent to the ISS, docking hours after launch instead of the usual 2-day rendezvous.

The three person crew includes NASA astronaut Chris Cassidy and Russian cosmonauts Pavel Vinogradov and Alexander Misurkin. Launch is scheduled for 4:43 pm EDT (3:43 pm Central Time in Houston) or 2:43 am March 29 at the Soyuz launch site at Baikonur Cosmodrome, Kazakhstan.

Docking is scheduled for 10:32 pm EDT (9:32 pm Central), about 6 hours later. Hatches between the ISS and Soyuz are expected to open at 12:10 am March 29 EDT (11:10 pm March 28 Central Time).

The same-day docking has been sucessfully demonstrated on three robotic Progress resupply flights. The advantage of letting the crew dock the same day as launch is they can spend less time in the extremely cozy confines of the Soyuz spacecraft. The disadvatange is that it will be a long day for the crew, who must arise, dress in their spacesuits and enter the Soyuz well in advance of launch and then spend six hours after launch in their seats, still in their spacesuits. During a typical 2-day rendezvous, once they are in orbit they can get out of their seats and move around, change into more comfortable garb, and use the facilities.

Soyuz TMA-08 spacecraft just prior to being moved to its launch site.

Photo credit:  NASA/Victor Zelentsov

The question is whether being confined to their spacesuits and their seats for so many hours is an improvement over spending two days in the Soyuz when they are able to get out of their seats and spacesuits. The comfort issues, which can affect crew performance, are expected to play a role in decisions on how often to use this method of docking with the ISS.

NASA will cover the launch, docking and hatch opening on NASA TV.