DATE:30/10/08

SOURCE: Flight International

Spare Hubble control box failure threatens telescope mission

By Rob Coppinger

The failure of a Hubble Space Telescope (HST) control unit during qualification testing is threatening the joint NASA, European Space Agency telescope's future and prospects for its final servicing mission.

The spare unit is being tested for inclusion in the delayed Space Shuttle STS-125 flight for the HST Servicing Mission (SM) 4. The SM4 mission was too install only two replacement instruments in the HST before the telescope's control unit, science data formatter's side A failed on 27 September leading to the Shuttle's 14 October launch being scrubbed. The HST's systems have a side A and B, one being the backup for the other.

Flight has learnt that the spare unit's side A failed a qualification test and engineers have concluded that they have an "intermittant problem". The investigation into this and the potential need to manufacture a new unit could see SM4 delayed into 2010, when the Shuttle fleet is to be retired. In September NASA had announced a possible STS-125 delay to February but has since considered a May date. But that was before the unit failure.

"The replacement [units] to repair the latest Hubble problem are not in good shape. They are failing qualification testing. It looks like STS-125 will not launch any earlier than April [2009], perhaps never," says a space programme source.

NASA Goddard Space Flight Center declined an interview with Flight, explaining that it is organising a media teleconference on 30 October that the center says: "will address most, if not all, of your questions."

http://www.flightglobal.com/articles/2008/10/30/318117/spare-hubble-control-box-failure-threatens-telescope.html