Shuttle Astronauts Scan Heat Shield

Editor?s Note: This story was updated at 7:00 p.m EDT.

Astronauts aboard NASA?s space shuttle Discovery took a first look at their spacecraft?s heat shield today even though they lack a vital tool to hunt for any damage to the vehicle from its Saturday afternoon launch.

Discovery launched toward the International Space Station (ISS) yesterday at 5:02 p.m. EDT (2102 GMT) to deliver Japan?s massive Kibo research module to the orbiting laboratory. But the new orbital room is so large, the shuttle had to fly without its laser-tipped sensor boom, a required tool for now-standard heat shield inspections on all NASA shuttle flights.

Instead, Discovery?s seven-astronaut crew conducted a limited survey today using a camera at the tip of the shuttle?s 50-foot (15-meter) robotic arm.

?That sort of gives us a good idea of the situation we?re in before we go on to docking,? Discovery shuttle pilot Ken Ham said before launch. ?It?s a pretty well thought out plan.?

Discovery is set to dock at the space station on Monday at 1:54 p.m. EDT (1754 GMT). But before the shuttle arrives, astronauts aboard the orbiting lab will take high-resolution photographs of its heat shield - also a standard safety measure since the 2003 Columbia tragedy - so engineers can search for any dings in the thousands of heat-resistant tiles coating its nose and underbelly.

The shuttle astronauts are also slated to also perform a full heat shield inspection later in their planned 14-day mission using a 50-foot (15-meter) inspection boom left outside the space station by a previous shuttle crew.

Commanded by veteran shuttle flyer Mark Kelly, Discovery?s STS-124 astronauts plan to install the Kibo lab and relocate its storage module during three spacewalks, as well as swap out one member of the space station?s three-man crew. They are also hauling a spare toilet pump to fix the station's balky Russian-built commode.

About the size of a large tour bus, the $1 billion Kibo lab module is 37 feet (11 meters) long, weighs about 32,000 (14,514 kg) and has two windows, a robotic arm and its own, small airlock. It is the second of three separate segments that make up Japan?s entire Kibo facility, and will join a small storage module already at the station. A porch-like external platform for space exposure experiments is slated to launch next year.

Shuttle survey

Ham and his crewmates began today?s limited scan of the heat-resistant panels along Discovery?s wing edges just after 11 a.m. EDT (1500 GMT). The survey ran about two and a half hours, but was limited by the Discovery?s robotic arm reach, which is only about half that of combined arm-inspection boom assembly.

?That means that we can?t really look too much underneath the port wing,? shuttle flight director Matt Abbot said before flight, adding that the upper portions of both wings should be visible.

NASA has kept a close watch on the heat shield integrity of its shuttle fleet since 2003, when a piece of foam insulation fell from the shuttle Columbia?s external tank and punched a hole in the carbon composite panels on its left wing leading edge. The damage led to the loss of the orbiter and its seven-astronaut crew as they reentered the Earth?s atmosphere.

Since then, shuttle astronauts have used lasers and cameras at the end of their shuttle inspection boom to ensure their spacecraft is in good health. NASA also redesigned its shuttle fuel tanks to limit the amount of foam insulation shed during liftoff.

Discovery?s STS-124 mission is the first shuttle flight to use a fuel tank built from scratch with all the new modifications. Mission managers wanted to test the new tank before using another one to feed the shuttle Atlantis?s planned October launch to the Hubble Space Telescope.

NASA space operations chief Bill Gerstenmaier said Saturday that an initial survey of launch video footage found about five pieces of foam debris that popped free from Discovery?s external tank after liftoff. None of them are expected to pose a risk to the shuttle or its crew, he added.

One thin piece appeared to bounce off Discovery and remain intact, but all of the events occurred after first two minutes and 15 seconds of flight, when debris cannot accelerate fast enough to cause serious damage to the orbiter?s heat shield, Gerstenmaier said.

?Ultimately, we would like to reduce the amount of foam that comes off the tank,? Gerstenmaier said. ?I don?t think we?ll ever get it to zero, but if we can get it to where it occurs late like it did on this flight than we?re in a good configuration.?

NASA is broadcasting the planned launch of Discovery's STS-124 mission live on NASA TV on Saturday. Click here for SPACE.com's shuttle mission updates and NASA TV feed.

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• Complete Space Shuttle Mission Coverage