"The chief medical commission ruled that both the main and the backup crew members were fit for performing a space flight," said Sergei Krikalyov, head of Russia's Gagarin Cosmonaut Training Center.
The main crew comprises Russian cosmonauts Pavel Vinogradov, Alexander Misurkin and Christopher Cassidy of NASA.
The backup crew lists Oleg Kotov and Sergei Ryazansky of Russia and Michael Hopkins.
Vinogradov and Kotov have taken two spaceflights.
For Cassidy, this will be the second spaceflight in total but the first onboard Russia's Soyuz spacecraft.
None of the backup crew members have flight experience so far.
The Soyuz-FG rocket, carrying the Soyuz TMA-08M spacecraft, was rolled out to the launch pad at the Baikonur space centre in Kazakhstan Tuesday. The launch is set for 12.44 a.m. Moscow time Friday (8.00 p.m. GMT Thursday), with docking to the ISS planned for some six hours later.
This will be the first manned flight to the ISS under the "short" six-hour flight programme earlier tested by the Progress space freighters. All previous manned Soyuz missions were carried out under the two-day scheme.
--IANS (Posted on 28-03-2013)