Archive by category | Space shuttle Atlantis launch

The Precautionary Principle

It’s a sign of just how cautious NASA has become that they decided to stand down today. The questionable engine cut-off sensor was one of four that are used to shutdown the engine if the hydrogen fuel runs low. The shuttle needs just two of its four sensors working, and the whole cut-off system itself is a backup: the navigational computers typically turn things off automatically at the right altitude and speed. Even if they don’t, Atlantis carries an extra 300 kilos of hydrogen to prevent the engines running dry.  Read more

Hydrogen Sensor Fails

Complicating the launch plans is the apparent failure of one of four hydrogen engine cut-off sensors on the shuttle’s main fuel tank (that’s the big orange one). Mission managers will now need to decide whether to launch with only three sensors, or scrub for 24 hours.  Read more

Faulty Wiring or no, the Shuttle is a “Go”

Mission managers made the case today for launching on Friday, despite the partial failure of a motor used to cool one of the Atlantis’s three fuel cells. The motor is still operational, but any further problem would cause it to shutdown. Astronauts would then have about ten minutes to shut off the entire cell before some presumably very bad would happen.  Read more