14 DAY TRIAL // The seven-astronaut crew aboard the Discovery space shuttle are now entering the final stages of their flight, as they prepare for their atmospheric reentry. A single crucial stage in the STS-119 mission remains – Thursday's inspection of the heat shield. This investigation is paramount to the safety of the crew on the ship, as NASA tries to ensure that the disaster that struck the Colombia shuttle during its 2003 reentry will never repeat itself. Pilot Tony Antonelli and mission specialist Joseph Acaba will be in charge of the scans, which will take them the better part of the day.
The two will use the Orbiter Boom Sensor System (OBSS) instrument for their effort. It's basically a long pole, laden with sensors, video cameras and lasers, able to determine if the heat shield has been damaged by space debris, micrometeorites, or other similar bodies. The concerns are amplified by the fact that Discovery has had to use its thrusters during the mission towards the ISS, in order to maneuver the finished, $100-billion orbital lab out of the path of a debris fragment, traveling at several thousand miles per hour.
“The crew was awakened at 6:13 am EDT today with the song 'Enter Sandman' by Metallica, played for Mission Specialist Joseph Acaba. Within a few hours [the two] will use the shuttle's robotic arm to grapple the Orbiter Boom Sensor System (OBSS) to kick off today’s inspection,” a release on NASA's official website says.
“Starting with the reinforced carbon-carbon panels that line the leading edge of the shuttle’s starboard wing, the crew will guide the OBSS so its cameras and laser sensors can examine the orbiter for signs of damage from orbital debris. The inspection moves from the starboard wing, to the nose cap, to the port wing. The OBSS should be returned to its berth on the starboard sill of the payload bay starting at 3:43 pm EDT,” the release also adds.
Talking about the increasing incidence of space debris threatening the International Space Station, LeRoy Cain, the deputy shuttle program manager at the American space agency, stresses that, “It's part of the business. It comes with the territory and we'll continue to do whatever is necessary to avoid debris where and when we know about it.” Discovery commander Lee Archambault pinpoints that, “We have had a couple of these in the last couple of weeks, but as a far as I know it's coincidental that we've had just a couple in this close timeframe,” referring to the fact that the ISS has been threatened two times in three weeks by space debris running loose in orbit.