NASA's space shuttle Discovery, seen here in an orbital view taken during its STS-116 mission by International Space Station astronauts, is due to land on Dec. 22, 2006.
Astronauts aboard NASA?s space shuttle Discovery scanned their spacecraft?s heat shield for any signs of damage on Tuesday, but couldn?t beam the results to Mission Control because of a main antenna dish malfunction.
The antenna failed to work just after Discovery launched Monday on a delivery mission to the International Space Station. Without the antenna, Discovery?s seven astronauts can?t send or receive big data packages, like beaming live video to Mission Control or receiving major revisions to their flight plan.
?We can?t talk through it. We can?t send commands through it. Really nothing works with it at this point,? shuttle flight director Richard Jones said in a Tuesday morning briefing.
That meant Discovery?s astronauts had to record the results of their shuttle inspection on 40-minute data tapes instead of beaming video and laser camera data straight to Mission Control. They had to use six tapes to store about 40 gigabytes of data from the inspection so that it can be sent to Earth later once Discovery reaches the space station [Discovery?s pre-dawn launch].
The astronauts used a 100-foot (30-meter) inspection boom tipped with laser sensors to scan the heat shield panels along Discovery?s wing edges and nose cap for any damage sustained during their Monday launch. ?The survey took hours.
?It?s a long day so we actually rotate through,? said shuttle pilot Jim Dutton, one of three Discovery astronauts who performed the scan, in a NASA interview.
The inspection is a standard part of every space shuttle mission since the 2003 Columbia disaster, where wing heat shield damage led to the loss of the spacecraft during re-entry. Seven astronauts were killed.
Since then, NASA has developed rigorous inspection techniques and repair methods to ensure heat shield integrity of its shuttles in flight. Tuesday?s inspection is the first of three planned surveys of the shuttle by its crew and astronauts on the space station.
Discovery is due to dock at the International Space Station Wednesday morning at 3:44 a.m. EDT (0744 GMT). The astronauts are working on a skewed schedule that requires them to sleep in the day and work at night. They?ll go to sleep at about 12:21 p.m. EDT (1621 GMT) today to rest up ahead of Wednesday?s docking.
The malfunctioning Ku-band antenna dish is 3 feet (1 meter) wide and about 7 feet (2.1 meters) long. It is one of several communication systems on Discovery, which also has UHF and S-band systems for voice and data transmission, but only the Ku-band system can send home video.
Without the antenna, Discovery?s rendezvous with the space station is expected to be a bit trickier, since the device is also used in a radar mode to give shuttle commander Alan Poindexter updates on Discovery?s approach and alignment.
Jones said the astronauts can use star trackers and other devices in place of the antenna?s radar.
Jones said that the antenna is tracking communications satellites in orbit, just not sending or receiving information. A similar antenna failure occurred during NASA?s STS-92 shuttle mission to the space station in 2000, he added.
It is unclear if the antenna can be repaired during Discovery?s 13-day mission. But so far, the glitch has not posed too much of a problem for Discovery?s crew or flight controllers on Earth, Jones said.
?I would characterize it right now as a minor inconvenience,? Jones said.
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SPACE.com is providing complete coverage of Discovery's STS-131 mission to the International Space Station with Managing Editor Tariq Malik and Staff Writer Clara Moskowitz based in New York. Click here for shuttle mission updates and a link to NASA TV.