Space Shuttle Astronauts Get Time Off

This story was updated at 7:43 a.m. EDT.

Astronauts aboard the space shuttle Discovery are due for some much-deserved time off Sunday as NASA engineers draw up new plans for the crew?s last spacewalk at the International Space Station.

Discovery?s seven-astronaut crew is scheduled to take about a half-day off to rest up from a packed spaceflight that has only become busier from daily changes to an already shortened mission plan.

?We?re ready to start the day,? Discovery skipper Lee Archambault radioed Mission Control this morning. ?We know it?s a little bit of a lighter day, but I?m sure you guys had a busy night overnight with a lot of planning.?

The crew?s latest hurdle is the upcoming spacewalk, a planned Monday excursion to pay a service call on the space station and move gear into position for the next construction flight.

An incorrectly placed restraint pin thwarted efforts by astronauts to set up a spare parts platform in a Saturday spacewalk, leaving cargo carrier half-deployed and tied down with tethers when they ran out of time to fix it and set up a second platform. Mission managers worked through the night to replan Monday?s spacewalk to wrap up the unfinished work and has divers in the water of its immense swimming pool used for spacewalk training to come up with the best repair plan.

?We will respect the crew?s off-duty time,? space station flight director Kwatsi Alibaruho told reporters late Saturday. ?They?ve accomplished an incredible amount already, so they?ve certainly earned some time off.?

Break time in space

Discovery launched toward the space station on March 15 and arrived last Tuesday to swap out one member of the orbiting lab?s crew and install the outpost?s final set of U.S. solar arrays. The mission was delayed a month by technical concerns with the orbiter only to have its launch pushed back four days by a gas leak.

The delays cut a day and a spacewalk from the shuttle crew?s already packed mission in order to complete the construction before a Russian Soyuz ferrying carrying more astronauts arrives later this week, so today?s scheduled half-day off should come as a welcome relief.

At least one Discovery astronaut may spend his free time floating down the space version of memory lane.

Shuttle astronaut John Phillips is the lead space station robotic arm operator on Discovery?s crew, but he also spent six months living aboard the orbiting laboratory in 2005.

?Who knows, maybe I?ll get to spend the night in the little cubby that I slept in while I was there if no one?s sleeping in it now,? Phillips said before flight. ?I want to go try some of that good Russian space food in the galley, and maybe I?ll run on their treadmill.?

Japanese astronaut Koichi Wakata, who launched aboard Discovery to begin a three-month mission at the station, is due to spend part of his day familiarizing himself with his new orbital home, NASA officials said. Wakata is the first astronaut from Japan to live aboard the station long-term and is replacing NASA spaceflyer Sandra Magnus, who will return home aboard Discovery to complete her own four-month mission.

Some of Discovery?s astronauts will discuss their flight so far with reporters on Earth during a series of television interviews.

Later today, the astronauts will conduct a full test of the station?s urine recycler, which appears to be in good working order after two days of repairs. On Friday, astronauts replaced a broken distillation assembly in the urine recycler, which spins like a centrifuge to begin filtering urine back into drinking water. A day later they turned it on while empty in a dry shakedown run.

?It sounded really nice and quiet,? Magnus said after the replacement. The old distillation unit made loud vibrations when spinning until it broke down for good last December.

The station?s urine processor is part of  a larger system designed to collect astronaut urine, sweat and condensation from the cabin atmosphere and filter it through a seven-step process back into pure drinking water.

Alibaruho said astronauts will fill the repaired urine processor with stored urine and then begin the recycling process, which should take four or five hours. If the device continues to operate well, water samples from the overall system will be taken later in Discovery?s flight to be returned to Earth.

NASA wants to test the water samples and certify the station?s water recycling system for human consumption in order to help support larger, six-person crews at the outpost later this year.

?Basically, that unit is functioning normally,? Alibaruho said.

Discovery has passed the midpoint of its 13-day mission to the space station. The shuttle is slated to undock from the orbiting lab and land on March 28.

SPACE.com is providing continuous coverage of STS-119 with reporter Clara Moskowitz and senior editor Tariq Malik in New York. Click here for mission updates and SPACE.com's live NASA TV video feed.

• Video - Discovery's Mission: Space Station Power Up!
• New Video - Discovery's STS-119 Night Launch
• New Show - Inside the International Space Station