Spaceflight Now




Crew says NASA has turned the corner after Columbia
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: July 14, 2006

The Discovery astronauts closed up the Leonardo logistics module today and geared up to detach it from the space station and re-install in the shuttle's cargo bay for return to Earth. With undocking from the station on tap Saturday, shuttle pilot Mark Kelly said the crew has accomplished virtually all of the mission's objectives, clearing the way for station assembly to resume this fall.

"We're getting close to meeting all our mission objectives," Kelly told CBS News during an in-flight interview. "Our commander, Steve Lindsey, right now about 30 feet behind us is closing out the logistics module. We've completed all the (supply and equipment) transfers, we've completed all the objectives with our three EVAs (spacewalks), the space shuttle Discovery's in great shape for a return trip home on Monday."

Asked if Discovery's flight will help NASA turn the corner and shift its focus from recovering from Columbia to resuming space station assembly, spacewalker Mike Fossum said he hoped so, adding "we needed this mission to get a lot of these objectives (accomplished), to reinforce our ability to do our own inspections, to test our ability to get access to different places on the shuttle's wing and underbelly if we needed to get there to do repair. We've done some testing on the future repair capability. So we're feeling good about that, we've answered a lot of those questions almost completely and I think we're ready to get rolling."

Before the 2003 Columbia disaster, when NASA was gearing up to begin the same stretch of assembly missions currently facing the agency, mission managers frequently spoke of the "wall" of spacewalk challenges facing construction crews.

Piers Sellers, who joined Fossum for three spacewalks during Discovery's current mission, agreed "there's really a lot to be done. It is kind of a wall."

"Every flight has got to get through its EVA tasks and install its equipment before the next flight can go," he said. "I mean, that's really the way the sequence works, so it's going to be a lot of hard work. It's a lot of hard work for a lot of people on the ground working furiously to make this happen."

NASA hopes to resume station assembly flights with launch of the shuttle Atlantis around Aug. 28 to mount a huge solar array and a massive rotary joint on one side of the station's main truss. The Russians plan to launch a fresh space station crew later in September and bring two outgoing crew members back to Earth. If all goes well, Discovery will return to the lab complex in late December to continue building the solar array truss, to deliver another full-time station crew member and to give European Space Agency astronaut Thomas Reiter a ride home.

"This flight and the one last summer, together they're the 'return to flight' missions and we feel like we've done all the tests and met the objectives and we feel like the whole program is back on track to assemble the space station and move on back to the moon and to Mars," robot arm operator Lisa Nowak told another reporter. "And we're looking forward to all of that."

In a morning execute package of daily instructions to the crew, flight controllers said Nowak and crewmate Stephanie Wilson had completed more robotic arm work than any other shuttle crew.

"Good morning, Discovery," the morning message to the crew read. "We hoped you enjoyed your time off (Thursday), Ścause guess what, it's time for more arm ops. Unofficially, we believe this flight has had the most robotic operations to date. The PDRS and ROBO folks would like to say thanks to you all, and especially the 'ROBO chicks.' They have definitely earned the title.'

Today, the "robo chicks" plan to use Discovery's robot arm and a long inspection boom to carry out laser scans of the shuttle's left wing leading edge panels. After undocking Saturday, they will re-inspect the shuttle's nose cap and starboard leading edge panels for any signs of damage due to impacts that might have occurred after the ship reached orbit.

Here is an updated timeline of today's activities (in EDT and mission elapsed time; includes NASA TV sked/rev. O):


01:08 AM    09  10  30  STS crew wakeup (flight day 11)
01:38 AM    09  11  00  ISS crew wakeup
03:48 AM    09  13  10  MPLM cargo module egress
04:03 AM    09  13  25  MPLM deactivation
04:03 AM    09  13  25  Media interviews
04:23 AM    09  13  45  Middeck transfers
05:28 AM    09  14  50  Spacesuit transfer
05:53 AM    09  15  15  MPLM vestibule depressurization
07:13 AM    09  16  35  Crew meals begin
08:13 AM    09  17  35  Station robot arm (SSRMS) grapples MPLM
08:23 AM    09  17  45  MPLM bolts backed out
09:00 AM    09  18  22  Mission status briefing on NASA TV
09:08 AM    09  18  30  MPLM pulled away from Unity module
10:43 AM    09  20  05  MPLM berthed in shuttle bay
11:23 AM    09  20  45  SSRMS ungrapples MPLM
11:38 AM    09  21  00  SSRMS grapples MBS
12:28 PM    09  21  50  SSRMS ungrapples lab
01:18 PM    09  22  40  OBSS port survey
03:13 PM    10  00  35  Rendezvous tools checkout
05:00 PM    10  02  22  Post MMT briefing on NASA TV
05:08 PM    10  02  30  STS/ISS crew sleep begins
06:00 PM    10  03  22  Daily video highlights reel on NASA TV

The so-called "late inspections" were added to the flight late in the crew's training flow after engineers decided the risk of catastrophic damage from such orbital impacts warranted an additional looks.

Kelly said engineers "don't really know what the risk is. It's pretty low, we've been flying space shuttles for a long time and we've never had any kind of critical damage from a micrometeoroid. So it's pretty remote."

Before launch, Steve Poulos, manager of the orbiter projects office at the Johnson Space Center, said the odds of a catastrophic impact due to space debris or micrometeoroids "is about 1-in-210, something on that order." By doing the late inspections, the odds will improve to 1-in-280 and possibly as low as 1-in-350, based on the performance of the sensor package on the end of the inspection boom.

It will take ground engineers a day or so to assess the late inspection data, but "based on what we've seen over the last 10 days, the inspections we've done, we've got a great ship," Kelly said. "It's ready to come home. We'll be doing that on Monday morning and it's going to be a safe landing, hopefully at the Kennedy Space Center if the weather's good.

"The space shuttle is ready to go and after this flight, I think we're really in a good configuration and we're pretty much set up to continue assembly of the space station and continue to fly the shuttle, hopefully like we did before 2003."

Asked how confident he is about the health of Discovery's heat shield, Kelly said: "We're real confident. We're going to look at it one more time, but based on what we've seen so far, knowing what the risk is, I think all of us feel really comfortable."

"Looking out the window the other day and looking down both wings, they're looking like they're in great shape, similar to when we saw them when the orbiter was being processed," he said.

The only technical problems of any significance are a very slight pressure decrease in the fuel tank of an auxiliary power unit, or APU, and trouble with stuck thermostats in a second APU.

Engineers are not yet sure whether the leak is nitrogen, used for pressurization, or hydrazine, the volatile fuel that powers the APU. Either way, Kelly said the leak was so small it was not a major concern.

"It's pretty minor," he said.

But given the critical nature of APUs, NASA engineers are keeping a close eye on the hydraulic powerplants. For readers interested in additional details, here's the latest thinking on the issue from NASA's Mission Management Team:

Source: NASA daily execute package for Flight Day 11

APU 3 GG/Fuel Line/Pump/Valve Heater - As a quick review, both the A and B heaters appear to be controlling the upper limit on the overtemp thermostat. We are currently on the A heaters and the system is controlling well. Functionally, there are no issues with operating on the overtemp thermostat. We are still investigating the fault tree to try and determine what would cause both the A and B control thermostats to fail. Some work was done at KSC in this area, but neither of the control thermostats was disturbed. The leading theory continues to be that either the thermostats or the heaters may have locally debonded. Workarounds exist for the next failure - if the B heater failed, we would switch back to the A. If that B heater failed, we would change attitudes after undocking to keep APU 3 warm or ask you to perform switch throws to manually control the heaters. If the heater fails on, the crew reaction time is about an hour after you get the alarm so there are no concerns for out of control temps on the fuel line.

APU 3 is not considered failed for entry or to even have a loss of redundancy. There is one small delta for entry - we'll swap to the B heater in the entry checklist to meet the APU injector temperature limits and likely turn the heaters off after APU 3 start.

APU 1 Tank Pressure Decay - The APU 1 fuel tank pressure continues to decay slowly. As of today it does not appear that we will be able to conclusively determine if the leak is N2 or hydrazine. The pressure decay has remained stable throughout the mission and there is no reason to assume that the leak rate will change. If the leak is GN2, we have lost about 18 psi so far and will have lost 33 psi by EOM - there will be plenty of GN2 still remaining to support entry operations on the APU. The minimum start pressure is 100 psi and we expect to be at 213 psi for EOM.

If the leak is hydrazine and of course we are not sure of that, we have lost about 10 lbs so far and will have lost 17 lbs by EOM. The leak rate of hydrazine is calculated to be 18 cubic centimeters per hour - very small. At this leak rate and based on the pod environment, analysis has shown that the hydrazine will phase directly into vapor and not form ice or liquid. The vapor exits the vent doors on orbit and there is a minimal concentration remaining. In fact at this leak rate, the hydrazine vapor concentrations will remain well below the flammability limits in the aft compartment for entry. This theory is somewhat corroborated by the fact that there are no indications of localized cooling on any temp sensors that would be indicative of a liquid fuel leak. Of course that also supports the possibility that the leak is N2, which is obviously the best case.

As mentioned yesterday, the N2 fill Quick Disconnect (QD) did have a leak preflight prior to the APU confidence run, but after cycling the QD poppet the leak was cleared (fairly common occurrence) and a flight cap is currently installed on the QD. It is still not clear that this preflight N2 leak could be related to the in-flight leakage we are seeing. The pre-flight data has been reviewed and there was no fuel leak observed pre-launch.

For information the APU 1 and 2 fuel tanks are located on the port sidewall of the aft compartment about 8 feet below the APU's which are near the top of the 1307 bulkhead. The teams continue to work around the clock on the ground to quantify the effects of the small N2 or fuel leak and the forward plan for entry.

Spaceflight Now Plus
Additional coverage for subscribers:
VIDEO: DAY 9 MISSION STATUS BRIEFING DIAL-UP | BROADBAND
VIDEO: BEHIND THE SCENES IN MISSION CONTROL FOR EVA 3 PLAY
VIDEO: HELMET-CAM FOOTAGE DURING THE HEAT SHIELD REPAIR PLAY
VIDEO: SPACEWALKERS TRAVEL TO REPAIR TEST SITE PLAY
VIDEO: PIERS SELLERS TESTS INFRARED INSPECTION CAMERA PLAY
VIDEO: SELLERS HITCHES RIDE ON SPACE STATION ARM PLAY
VIDEO: PREVIEW OF SPACEWALK NO. 3 PLAY

VIDEO: DAY 8 MISSION STATUS BRIEFING DIAL-UP | BROADBAND
VIDEO: DAY 7 MISSION STATUS BRIEFING DIAL-UP | BROADBAND
VIDEO: BEHIND THE SCENES IN MISSION CONTROL FOR EVA 2 PLAY
VIDEO: SPACEWALKERS BOLT THE NEW REEL TO THE STATION PLAY
VIDEO: INSTALLATION OF NEW REEL NOT EASY PLAY
VIDEO: FOSSUM CARRIES REPLACEMENT REEL TOWARD ISS PLAY
VIDEO: SPACEWALKERS BRING FAILED REEL TO THE SHUTTLE PLAY
VIDEO: FAILED RAILCAR CABLE REEL REMOVED FROM ISS PLAY
VIDEO: SELLERS REPLACES FAILED CABLE CUTTER DEVICE PLAY
VIDEO: STATION ARM HOISTS PUMP MODULE FROM SHUTTLE PLAY
VIDEO: ASTRONAUTS PREP PUMP MODULE FOR TRANSFER PLAY
VIDEO: PREVIEW OF SPACEWALK NO. 2 PLAY
VIDEO: SRB CAMERA LIFTOFF TO SPLASHDOWN PLAY
VIDEO: JOINT CREW NEWS CONFERENCE DIAL-UP | BROADBAND
VIDEO: DAY 6 MISSION STATUS BRIEFING DIAL-UP | BROADBAND

VIDEO: DAY 5 MISSION STATUS BRIEFING DIAL-UP | BROADBAND
VIDEO: SPACEWALK NO. 1 CONCLUDES PLAY
VIDEO: FOSSUM PRACTICES REPAIR ACTIONS PLAY
VIDEO: BOTH SPACEWALKERS GET ON THE BOOM PLAY
VIDEO: SELLERS CONDUCTS STABILITY TESTS PLAY
VIDEO: SPACEWALKERS GATHER TOOLS FOR TESTS PLAY
VIDEO: SELLERS AND FOSSUM BEGIN EVA 1 PLAY
VIDEO: PREVIEW OF SPACEWALK NO. 1 PLAY

VIDEO: ROBOT ARM MOUNTS CARGO MODULE TO THE STATION PLAY
VIDEO: LEONARDO CARGO MODULE LIFTED OUT OF PAYLOAD BAY PLAY
VIDEO: FLIGHT DIRECTOR EXPLAINS MODULE INSTALLATION PLAY
VIDEO: OVERVIEW OF CARGO CARRIED IN LEONARDO PLAY
VIDEO: LIVE RADIO INTERVIEWS WITH CREW CBS | FOX | ABC | NPR

VIDEO: DAY 3 MANAGEMENT TEAM BRIEFING DIAL-UP | BROADBAND
VIDEO: POST-DOCKING MISSION STATUS DIAL-UP | BROADBAND
VIDEO: SHUTTLE CREW FLOATS INTO THE STATION PLAY
VIDEO: DISCOVERY DOCKS TO THE SPACE STATION PLAY
VIDEO: WATCH THE ENTIRE PIROUETTE BACKFLIP MANEUVER PLAY
VIDEO: FLIGHT DIRECTOR EXPLAINS RENDEZVOUS AND DOCKING PLAY

VIDEO: INITIAL TANK ASSESSMENT DIAL-UP | BROADBAND
VIDEO: DAY 2 MISSION STATUS BRIEFING DIAL-UP | BROADBAND
VIDEO: FLIGHT DIRECTOR EXPLAINS INSPECTIONS WITH BOOM PLAY
VIDEO: FLIGHT DIRECTOR EXPLAINS ROBOT ARM INSPECTIONS PLAY

VIDEO: THE FULL LAUNCH EXPERIENCE PLAY
VIDEO: RIDE ALONG DURING LAUNCH VIA CREW MODULE CAMERA PLAY
VIDEO: AMAZING FOOTAGE FROM WB-57 HIGH-ALTITUDE AIRCRAFT PLAY

VIDEO: SHUTTLE LANDING FACILITY TOWER PLAY
VIDEO: PLAYALINDA BEACH TRACKER PLAY
VIDEO: BEACH MOUND TRACKER PLAY
VIDEO: PATRICK AFB TRACKER PLAY
VIDEO: UCS 23 TRACKER PLAY
VIDEO: UCS 11 TRACKER PLAY
VIDEO: CS 6 TRACKER PLAY
VIDEO: CS 2 TRACKER PLAY
VIDEO: CS 1 TRACKER PLAY
VIDEO: VEHICLE ASSEMBLY BUILDING ROOF PLAY
VIDEO: LAUNCH PAD FRONT CAMERA PLAY
VIDEO: COMPLEX 39 PRESS SITE PLAY
VIDEO: LAUNCH PAD SIDE VIEW PLAY
MORE: STS-121 VIDEO COVERAGE
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