NASA astronauts will spend the weekend in quarantine as the launch of the space shuttle Endeavour got pushed back at least 72 hours today thanks to a malfunctioning series of heaters in its hydraulic system. That may be good news for Gabrielle Giffords, whose husband, Mark Kelly, is leading the shuttle mission. Giffords, Kelly, and the crew met with President Barack Obama today when he and the first family dropped by Kennedy Space Center. At a news conference this afternoon, NASA officials said the crew and its families would stay in quarantine and would pass the weekend at NASA's beach house. That's right, NASA has a beach house. It looks great, too.

The guys at Kennedy did their best to keep the techno-babble to a minimum while explaining the malfunction, but they have a hard time on that front. Essentially what happened is this: The shuttle, like all aircraft, uses a hydraulic system to operate a lot of its mechanical parts. The power to pressurize that system comes from units called auxiliary power units (APUs). Those APUs are powered by a very flammable substance called hydrazine, which, in addition to catching fire easily, also freezes when it gets cold (and it is very cold in space). So they heat it using a series of electric heaters, and it was one or two of those heaters, or possibly the thermostat controlling those heaters, that malfunctioned. If the hydrazine freezes and then thaws on reentry, it can leak out and catch fire.

"I’d rather be on the ground wishing I was in the air than in the air wishing for the safety of the ground," joked Kennedy director Bob Cabana at the top of the press conference, but it was clear all involved were disappointed they couldn't launch. Now they'll have to wait a full 24 hours to fully drain the shuttle's fuel tank, then go see if they can fix the problem, then allow another chunk of time to refuel. They won't be able to green-light the launch until noon on Sunday at the earliest, and they won't be able to actually launch until Monday afternoon.

But the astronauts are keeping a good face. A video that streamed on NASA's Web site at the end of the press conference showed them joking around and shaking hands with the president, and the first family got a tour of the center, and of Atlantis, the shuttle due to launch next month. Kieth Koffler's White House Dossier has a clip from the pool report of the visit:

Obama met with rep giffords before he met with the crew at nasa. This is information they provided us on background, which can be attributed to a white house official

Potus met with Rep. Giffords for approx 10 minutes before he came down to meet the full crew. Prior to going in to see her, Potus greeted Mark Kelly in a corridor. “I bet you were hoping to see a rocket launch today,” Mr. Kelly said. Replied Potus: “We were hoping to see you.” They shook hands and embraced. Mr. Kelly updated the President and First Lady on Rep. Giffords’ condition, and then they went down the corridor to see her.

We won't know for at least 48 hours whether there will be a launch on Sunday, so as long as the astronauts are taking the weekend at a prime Florida beach house, it makes sense for the rest of us to do likewise. Or at least to relax in the apartment with a window open and our space shuttle scale model.