Tech Enthusiast. Nature Lover. Computer Geek. rsyslog lead developer.
The international space station ISS crew has headed outside of the orbiting complex to check the contamination of the starboard solar array rotary joint (SARJ). They are performing this task while I am writing. First results are expected during the course of today, with a detailed analysis to follow some time later (depending on the findings).
Side-Note: Atlantis tanking test will begin in roughly an hour from now. Final preparations are underway.
The international space station ISS crew will put the time until the next space shuttle visits the orbiting complex to good use. A spacewalk is scheduled for next Tuesday. It is part of the ongoing troubleshooting of the solar array rotary joint (SARJ) problem problem that troubles the station for some weeks now.
The SARJ issue reduces power generation from the solar array. This is currently no issue, but when more modules are added, it becomes a constraint. The Columbus module, to be delivered by Atlantis whenever STS-122 is ready to launch, can operate with currently available power. However, the Kibo module, rocketed into space with STS-123, will probably exhaust current power availability. As such, it is vital to solve the issue with the rotary joints.
Previous spacewalks found some material on the race ring, a result of abrasion. There is a backup race ring available, but it will not be activated until the root cause of the problem is understood.
And now let me quote the NASA ISS home page:
Station Commander Peggy Whitson and Flight Engineer Dan Tani will perform the 100th spacewalk in support of International Space Station assembly on Tuesday, Dec. 18. The spacewalk will focus on the starboard solar arrays. Whitson and Tani will examine the starboard Solar Alpha Rotary Joint (SARJ) and return a trundle assembly to the station’s interior.
Whitson and Tani also will examine the Beta Gimbal Assembly (BGA). It tilts solar wings for optimal power generation. The starboard BGA has been locked since some power feeds to it were interrupted last Saturday.
While spacewalk preparations are under way, the docked Progress 26 cargo ship is being loaded with discarded items and readied for undocking on Dec. 21. Progress 27 will arrive at the station with supplies on Dec. 26.
Now I know why there is no tanking test today. CBS’ status report (a long reading with many details) provides the reason: it is to preserve the capability to do an extra EVA (“extravehicular activity”, also known as a “spacewalk”) on the STS-122 mission.
Each launch attempt draws at least a bit from the internal consumables. Let me quote the relevant part from CBS’s page:
In the meantime, NASA managers ruled out a fueling test Friday and decided instead to top off the shuttle’s onboard supply of liquid hydrogen to power the ship’s electricity producing fuel cells. That would permit launch attempts Saturday and Sunday and still provide enough on-board supplies for a two-day mission extension and the addition of a fourth spacewalk.
This makes an awful lot of sense if you take the problems with the international space station’s solar array rotary joint into account. While that poses no problem for Columbus, I think the Kibo module can not be attached (or at least not sufficiently be powered) if the SARJ issues has not been solved until then.
NASA is hoping for a two-day mission extension to do an extra spacewalk in support of the SARJ issue. However, this is only possible if consumables permit. Having full tanks on launch is a number one requirement to achieve that goal…
The agency-level flight readiness review held yesterday concluded with the expected December, 6th launch date for Atlantis STS-122 mission. This continues Atlantis’ exceptionally well processing flow. No major problems occurred and this is probably one of the cleanest mission preparations for a long time.
Space Shuttle Atlantis is sitting at launch pad 39A and will rocket into space at 4:31p EST next Thursday. It will deliver the European Columbus space lab. It will be attached to the Harmony module which was brought up into space by Discovery’s STS-120 mission.
Meanwhile, the international space station crew has more or less finished the connection of Harmony to its final destination. This is a perquisite for STS-122, as Columbus will be mounted on one of Harmonies docking port. There are some news on a failed leak check, but it is said that this was most probably a sensor issue, not an actual leak. Sensor problems are common and so it looks very good from the ISS point of view, too.
What is becoming an increasing concern is abrasion in a solar array rotary joint (SARJ). This was detected a bit prior to STS-120. Discovery’s crew brought some samples back to earth, which are now being analyzed. Some more images and samples have been collected by the ISS crew. While the SARJ issue is no constraint for STS-122, it could (and probably will) affect future missions. Without a properly-working SARJ, the station can not generate enough power to support its final configuration. As far as it looks now, the repair will be quite complex and require a number of spacewalks, maybe carried out in February’s STS-123 mission. But it is way to early to know anything exactly – engineers are still evaluating the problem.
Everything is going very smooth with Atlantis’ STS-122 launch. No matter where I looked, I do not find any information on problems. So no news again means excellent news!
The flight readiness review, the final approval of the launch date, is scheduled for this Friday. As it looks, this is more a formal act than something that will bring up surprises (but of course, you never know…). To quote the NASA space shuttle home page:
NASA managers will hold a flight readiness review on Friday at NASA’s Kennedy Space Center marking the next major milestone for mission STS-122.
NASA officials, space shuttle program managers, engineers and contractors will discuss the readiness of space shuttle Atlantis, the flight crew and payloads to determine if everything is set to proceed for launch. Managers will also select an official launch date at the end of the session. Launch is targeted for Dec. 6 on a mission to install the Columbus laboratory on the International Space Station.
A briefing following the meeting will include Associate Administrator for Space Operations Bill Gerstenmaier, Space Shuttle Program Manager Wayne Hale, International Space Station Program Manager Mike Suffredini and STS-122 Launch Director Doug Lyons.
The briefing will be broadcast live on NASA Television no earlier than 4 p.m. EST.
The real question is probably not if and when Atlantis will launch. The most discussed question currently is if the STS-122 mission is extended to allow a focussed inspection of the SARJ ISS solar array rotary joint. Anomalies were detected prior to STS-120 and inspection during recent spacewalks staged from the international space station showed signs of abrasion. This is an unexpected, not yet understood and potentially serious problem – so it is receiving priority for obvious reasons.
The additional inspection spacewalk requires a two-day mission extension. Other than its sister ships Discovery and Endeavour, Atlantis is not equipped with the station to shuttle power transfer system (SSPT). Thus, Atlantis can not support missions as long as its sister ships. So a two-day mission extension requires fully stocked consumables and is something that probably is not very easily done.