No major debris events seen in ascent video
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: December 10, 2006
"All in all it's going really well," said John Shannon, chairman of NASA's Mission Management Team at the Johnson Space Center in Houston. "All the reports that came in were that we had a very typical ascent, there were no surprises as of yet. We're just waiting for the inspection data to come down. We'll take a look at that and work it into the mission as appropriate."
Discovery's crew used a long sensor boom today to inspect the shuttle's reinforced carbon carbon nose cap and wing leading edge panels and the space station crew will photograph the heat shield tiles on the ship's belly during final approach before docking Monday afternoon. The linkup currently is targeted for 5:06 p.m.
For Discovery's launching, one ship was stationed to the north along the shuttle's ground track while the other was positioned to the south, closer to shore. During recovery operations, a man on the southern ship was injured, interrupting booster recovery operations.
"We did not put the southernmost ship where we typically do, it was not out at the recovery zone," Shannon said. "We had the northern ship out there, the southern ship was closer to the coast so we could get a good Doppler comparison between the two radars of anything coming off the stack.
"The southern ship went out with radar technicians and the plan all along was after the launch for it to come back to port, let the radar technicians off, on load some guys for the retrieval of the boosters and then steam overnight to the recovery zone. They got out there and there was an accident, I'm not going to get into exactly what happened, it's not life threatening, but a guy got hurt out there during the frustrum recovery.
"They halted recovery operations and started coming back and we got a Coast Guard helicopter to go out and pick him up and take him to the hospital and they're back on station to do the recovery starting tomorrow morning. So it's probably going to put our, what we call the open assessment of the solid rocket boosters, down by a day."
One of the ship-borne radars suffered a malfunction and was unable to collect data. Other radars noted two possible debris events during launch, both occurring well after the first minute and 35 seconds or so of flight when atmospheric density is high enough to result in high impact velocities.
Two bits of debris, presumably ice, could be seen floating away as the shuttle separated from the external tank. But nothing significant was seen actually striking the spacecraft.
Accelerometers mounted behind the wing leading edge panels detected six "events" during launch, four on the left wing and two on the right. All were in the 1.2- to 1.3-G range, just slightly above the 1-G limit that requires additional analysis.
Shannon said engineers aren't sure what might have triggered the readings, which are very similar to what was observed during the first three post-Columbia missions. It may be the result of the wing leading edge panels and support hardware settling, or snapping into place under the stress of launch, or it could be the result of very small bits of debris.
In any case, the events were at least 10 times weaker than the force needed to cause actual damage to the panels.
"The team sees nothing of concern at this time," Shannon said. "Of course, it was a dark launch at night, so we did not have all of the capability that we have enjoyed on STS-114, 121 and 115. The long-range cameras, though, showed typical performance. We could see a few very small pieces of foam or ice come off, none impacted the orbiter. The pad cameras showed very good performance.
"The ET feedline camera was interesting. We were able to get enough reflected lighting from the solid rocket boosters and the main engines to be able to see a few small pieces of what looked like foam that were highlighted against that plume. They were all well after the time of concern and it was very typical of what we've seen in past flights."
Overall, Shannon said, the team was pleasantly surprised by how well the cameras performed during the first night launching since November 2002.
"The long-range tracking cameras showed us a lot of detail on the lower part of the stack," he said, referring to the shuttle, its tank and boosters. "We're also able to see better at night when any piece of foam comes off of the stack if it goes into the main engine plume, it really brightens that plume up, you see a little streak in there and you can see it a lot better at night.
"As well, at external tank separation when the attitude control thrusters fired, it was bright as it could be and the imagery team has already taken snapshots of that data and made a preliminary assessment of the underside of the vehicle and said they don't see anything that's unexpected. So I was very encouraged by what we saw."
Photographing the tank after separation with a camera mounted in the shuttle's belly was not considered an option for Discovery's flight because separation occurred in orbital darkness.
"We didn't do it because we thought it was going to be dark," Shannon said. "But based on the results we saw from the attitude control firings, I think we will go ahead and do that (in the future) and just use that lighting from those jet firings to light the tank up for us."
Asked if the initial results gave him confidence in launching shuttles at night, Shannon said "we were confident before we stepped into this flight with night launch."
"We're very confident the vehicle is going to be safe to fly and we're also confident we have sufficient data through the radars and the imagery we did get to show we didn't have anything unexpected happen on the stack," he said. "As I said, it was as we expected."
The only other issues under discussion are problems with a controller used by one of the shuttle's cooling systems and a glitch in an automated system used to unlatch the ship's robot arm from whatever it is locked onto. Additional troubleshooting is planned for the controller issue but it is not expected to impact the mission. As for the robot arm, the astronauts will use a manual system to unlatch the snare mechanism as required. Again, no mission impact is expected.