Spaceflight

The thrust capability of the already selected NASA Crew Launch Vehicle, which would carry the agency’s yet-to-be-designed Crew Exploration Vehicle (CEV), could be the limiting factor for CEV mass, according to a senior official at the US space agency. The baseline requirement for the CEV, which consists of a crew capsule and service module, is a 25t vehicle.

However, the CEV has already been reduced from 5.5m (18ft) diameter to 5m and NASA has re-evaluated its landing system to try to save weight (Flight International, 22-28 March 2005).

The CLV has a five-segment solid rocket booster (SRB) first stage and a liquid oxygen/liquid hydrogen second-stage engine. Its thrust capability has not been revealed.

“Weight is always an issue,” said NASA Marshall Spaceflight Center exploration launch vehicles deputy director Dan Dumbacher, speaking at last week’s AIAA/Italian space agency space operations conference in Rome.

The CLV has been designed concurrently with the CEV. Dumbacher said the five-segment SRB would be reusable like its Shuttle forebear, and analyses showed that the current SRB casing design and o-rings can cope with the different forces now the SRB is a load-bearing first stage structure. The parachutes would have to be re-designed as the larger SRB falls further than the Shuttle’s. He also confirmed that his team has been asked to aim for a test flight in April 2009.