Spaceflight

New engine improves performance as Russian launch vehicle places astronomy satellite into polar orbit

The Samarra Space Centre Soyuz 2-1b launch vehicle had its inaugural flight on 27 December, placing the CNES/European Space Agency Convection Rotation and planetary Transits (Corot) astronomy satellite into a circular polar orbit.

Launched from Baikonur, the 2-1b uses the new third-stage RD-0124 engine that provides 34s more specific impulse, improving vehicle performance. It also uses digital flight control and other system upgrades validated by its sister Soyuz 2-1a rocket.

Corot is a 605kg (1,300lb), 380W spacecraft that will search for extra-solar planets for two and a half years. For the Corot launch, the 2-1b used the 4.1m (13.4ft)-diameter ST fairing. This is larger than the Soyuz's existing 3.7m-diameter SL fairing.

The ST was first used in October last year when a Soyuz 2-1a launched the MetOp-A weather satellite, which is part of a joint undertaking of three spacecraft between ESA and the European Organisation for the Exploitation of Meteorological Satellites. The 2-1b launch was performed under the joint responsibility of Arianespace and its Soyuz supplier affiliate Starsem. "[We] will use the improved Soyuz [2-1b] for commercial operations from Europe's spaceport in French Guiana," says launch provider Arianespace. That is expected to start in 2009 when Arianespace will use the Soyuz 2-1b as its medium-weight launcher for its family of vehicles.

It will sit alongside the company's heavylift Ariane 5 and the lightweight Vega booster, which may be used for commercial operations from 2008.