Managers at NASA must await checkout of a key piece of hardware for the Hubble Space Telescope before they can set the 2009 schedule for space station assembly missions and the first flight of a full-scale test version of the Ares I crew launch vehicle. The replacement Science Instrument Command and Data Handling (SIC&DH) unit that will be sent to the Hubble on the STS-125 mission has been in storage at Goddard Space Flight Center since the early 1990s, and has never been fully flight qualified. In previous ground tests the backup unit, designed to set up telescope-instrument data for transmission to waiting scientists, has generated spurious commands and displayed other anomalies that must be run to ground before it can replace the unit that failed Sept. 27. Certifying the backup SIC&DH for flight won't start until the telescope is reactivated in orbit at the end of this week. That will free the Vehicle Electrical System Test (VEST) facility at Goddard to check out the replacement unit. Results of that work will give NASA a better idea of the shuttle flight schedule over the next six months or so.
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