SpaceX-3: “The Word is Go”

At a noon press conference at the Kennedy Space Center today, ISS program manager Mike Suffredini, speaking from via phone, announced that the SpaceX-3 mission will remain on schedule for a Monday launch at 4:58: PM EDT.

There had been concerns that the launch would slip due to the failure of a backup computer command relay box, the multiplexer/demultiplexer (MDM). The MDM controls much of the station’s outer truss structure. Although the primary module is functioning normally, safety rules require redundancy for the arrival of ISS Visiting Vehicles.

In this case the chief concern was that a subsequent failure of the primary unit would leave controllers unable to alter the station’s solar arrays to avoid the thruster plumes created by incoming spacecraft. During a Sunday morning meeting however, station managers determined that a backup could be prepared by pre-setting the solar arrays to deploy when required.

Furthermore, the Dragon is carrying materials which will help astronauts swap components in a space walk which will take place after it arrives. Demonstrating the utility of its “late load” capacity, a T-38 flew in to KSC this morning carrying a type of gasket required to mount the MDM, obtained from Boeing.

The launch weather forecast has improved from 70-80% go, with a build-up of anvil clouds being the primary concern. If the launch does not take place, the next opportunity will come on Friday, but the weather window is closing, with a front expected to settle in over Central Florida for much of the rest of the week, dropping the odds to 60%.