The space shuttle Discovery's liftoff to the International Space Station was postponed for a third time because of a leak in the ground umbilical carrier plate at Launch Pad 39A, which prompted a scrub of Friday's launch attempt, NASA officials reported. Discovery's six STS-133 astronauts left NASA's Kennedy Space Center in their T-38 jets Friday afternoon to return home to the space agency's Johnson Space Center in Houston. Discovery's next possible launch opportunity comes Nov. 30, according to a NASA release.
The space agency also reported that mission managers will look at a crack in the external tank foam that developed as super-cold liquid hydrogen and liquid oxygen were being drained from the tank-although the crack did not develop until after the launch attempt was called off, NASA said. The planned launch last Wednesday had already been delayed due to electrical issues stemming from a main engine computer controller.
When Discovery heads to the ISS on its final mission, it will be taking with it two key components-the Italian-built Permanent Multipurpose Module (PMM) and Express Logistics Carrier 4 (ELC4)-that will provide spare parts and storage capacity to the orbiting complex. Discovery also will deliver Robonaut 2, which will become the first humanoid robot in space.
NASA engineers said they hope Robonaut 2, the latest generation of the Robonaut astronaut helpers, can help teach engineers how dexterous robots behave in space. "The hope is that through upgrades and advancements, it could one day venture outside the station to help spacewalkers make repairs or additions to the station or perform scientific work," a NASA release stated.
R2, as the robot is called, will launch inside the Leonardo Permanent Multipurpose Module, which will be packed with supplies and equipment for the station and then installed permanently on the Unity node. Once R2 is unpacked-likely several months after it arrives-it will initially be operated inside the Destiny laboratory for operational testing, but over time both its territory and its applications could expand. A NASA mission statement noted there are no plans to return R2 to Earth.
Discovery was NASA's third space shuttle orbiter to join the fleet at Kennedy Space Center and is currently the oldest orbiter in service. Early in its career, Discovery provided a base so astronauts could retrieve satellites, test new technologies and conduct two-week-long experiments in microgravity. NASA turned twice to Discovery for Return-to-Flight missions after accidents with shuttles Challenger and Columbia, and it launched the agency's landmark observatory, the Hubble Space Telescope.
A medallion from the Royal Society honoring explorer Capt. James Cook will be carried aboard the space shuttle during STS-133. Cook's third expedition of the Pacific Ocean included a ship named HMS Discovery, one of the vessels shuttle Discovery is named after. Also flying on Discovery will be two small Lego space shuttles, each with a tiny toy astronaut, to help celebrate a new educational partnership between the toy-building brick maker and NASA.
"I don't think you can take a final voyage of a ship of exploration and not take some moments to celebrate its history," said Mission Specialist Michael Barratt. "And I think many people know that our ship, Discovery, which is a ship of exploration, was named after several predecessor ships also named Discovery, all ships of exploration."