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 06:09 PM
November 18, 2009
Shuttle Delivers Spares
The Space Shuttle Atlantis arrived at the International Space Station (ISS) today (Wednesday, Nov. 18), delivering two huge carriers packed with spares for critical station systems.
The first Express Logistics Carrier (ELC-1), about the size of a small car, will be pulled from the shuttle's payload bay by the shuttle's robotic arm this afternoon. Astronauts Randolph Bresnik and Leland Melvin will "hand over" the ELC-1 from the shuttle arm to the station arm, controlled by shuttle crewmember Barry Wilmore and station crewmember Jeffrey Williams. The ELC-1 will then be "parked" on the Earth-facing side of the port (left) side of the truss.
The spares on this carrier are big heavy items such as a 600-pound control moment gyroscope, a 550-pound nitrogen tank, a 780-pound external cooling system pump, and a 1700-pound tank of ammonia. Though all these spares are weightless in freefall, they retain their mass, which means they have to be moved very slowly to keep the force (mass times acceleration) to a minimum.
The second carrier, ELC-2, will be shifted from the shuttle to the station on Saturday. The total mass of these two carriers is about 27,000 pounds, requiring the heavy-lift capability that only the space shuttle currently provides. A typical Russian Progress delivers about 5500 pounds to the station. Space X's Falcon cargo rocket, currently under development, is planned to lift about 23,000 pounds to ISS initially and up to 65,000 pounds eventually.
Spacewalkers Michael Foreman and Robert Satcher, Jr. will be camping out in the station airlock tonight in preparation for the first spacewalk of the mission Thursday. Foreman and Bresnik will be teamed up for the spacewalk on Saturday, and Satcher and Bresnik on Monday.
Atlantis is scheduled to undock next Wednesday and land at Kennedy Space Center on Friday, the day after Thanksgiving.
To the stars!
Posted by m_dyson at 12:00 PM
November 14, 2009
Shuttle Mission STS-129
The Space Shuttle Atlantis and its crew of six are ready for launch to the International Space Station (ISS). The weather forecast is good for liftoff at 2:28 p.m. Monday, November 16. The launch window closes on Friday.
STS-129 commander is Charles Hobaugh, the pilot is Barry "Butch" Wilmore, and missions specialists are Leland Melvin and spacewalkers Robert Satcher, Michael Foreman and Randolph Bresnik. Nicole Stott, who is currently winding up a three-month stay as a flight engineer on the ISS, will return home on Atlantis, the last astronaut to come home via space shuttle. (The Russian Soyuz will be used exclusively for crew exchange from now on.)
The flight is delivering essential spare parts for critical station systems. Three space walks and lots of robotic arm work are planned as part of this flight.
Also being delivered is a communications unit that will be used in a demonstration of Space X's Dragon capsule in 2010. Space X is participating in NASA's Commercial Orbital Transportation Services (COTS) program to provide cargo services to the ISS.
To view a summary of the 12-day flight, visit: http://www.nasa.gov/externalflash/129_flash/
To the stars,
Posted by m_dyson at 11:19 PM