November 24, 2009
As the hatch closed on the STS-129 mission today, I thought about how wonderful it was that we got to virtually share in both the heart-pounding scare of the crew being awakened by depressurization and smoke alarms--twice!--and also the joy of an astronaut's first walk in space topped off with the birth of his first daughter.
As a former flight controller, I can well imagine the reaction in Mission Control when those depressurization alarms went off on Thursday (Nov. 19). After all, the Leonid meteor shower peaked just days before, and a random fireball (that experts said was not a Leonid) exploded over several western states. But the data showed no leak, and the controllers soon determined it was a false alarm.
However, the station's systems had already responded automatically as they are supposed to do. The fans that keep the air flowing, shut off so as not to feed the leak. Without active air flow, hot air, which does not rise in freefall, stays put in a bubble around the hot equipment. Dust and lint in the air hang around, too--sometimes being electrostatically attracted to various things.
So no active air flow led to some dust triggering a smoke alarm in the Columbus module. It took the crew about an hour to reset everything and get back to sleep.
The alarms went off again on Friday night. This time, the two spacewalkers were in the airlock at a lower pressure to help purge their bodies of nitrogen. (The space suits are at a lower pressure, causing nitrogen to bubble out of the blood and sometimes get trapped in the joints--causing the bends--and also strokes.) The station systems responded to the depress alarm by bringing the airlock back to pressure so the astronauts could get back into the station--and presumably into a Soyuz escape ship.
This false alarm also triggered the fans to shut down, and led to two more fire alarms--one in Columbus, and the other in the Quest airlock.
I admit to having a very active imagination, but those alarms going off in the middle of the "night" while sealed in an airlock trying to sleep before my first ever space walk...would have scared me out of my wits! I'm looking forward to hearing Foreman's and Bresnik's stories after they return.
Because the pressure was raised from 10.2 to 14.7 psi, the spacewalkers had to go back to the old method of breathing pure oxygen for several hours to purge their systems instead. This delayed the start of their spacewalk on Saturday.
The false alarm was apparently caused by a problem in the new Russian Poisk module. I have not heard any details, but I doubt that the shuttle being docked was just a coincidence. I'm sure the flight controllers will figure it out, if they haven't already.
The spacewalk was lovely, though I only caught a few glimpses via my computer on a busy oh-my-the-company-is-coming-for-Thanksgiving Saturday. I can only imagine how Bresnik must have felt, trying to focus on his work with not only the gorgeous view of Earth to distract him, but knowing his wife was in labor, delivering their new baby daughter. Even so, the crew not only got all their work done, but did some extra "get-ahead" tasks.
The Bresniks adopted their son Wyatt, now 3, from the Ukraine last year--Bresnik saying that they got the call within 48 hours of his assignment to STS-129. And Abigail was born on Saturday night, during the mission, on the same day of Bresnik's first spacewalk.
As Bresnik said, "A miracle adoption as well as the miracle of childbirth, all in one year. We're just amazingly blessed."
Atlantis is scheduled to land the day after Thanksgiving at Kennedy Space Center. If so, the crew will return to Houston on Monday. What a joyous occasion that will be--time to celebrate a successful flight and the start of a new life.
This Thanksgiving, as we go around the table and share what we are thankful for, I'm going to add the wonder of human spaceflight to the list.
Posted by m_dyson at November 24, 2009 06:09 PM