July 20: Endeavour astronauts Thomas Marshburn and David Wolf float above Earth as they work on attaching spare parts to the space station.
July 21: Two robotic arms hand off the Japanese Logistics Element as it's tranferred from Endeavour to the space station.
July 17: Canadian astronaut Julie Payette temporarily occupies the pilot's station on space shuttle Endeavour.
July 18: Astronaut Tim Kopra in Endeavour's cargo bay during the first of five spacewalks planned for the current shuttle mission.
July 17: Space shuttle Endeavour approaches the International Space Station prior to docking.
July 17: Visible dings on Endeavour's underside thought to have been caused by debris during launch.
July 15: A fish-eye view from the gantry camera of space shuttle Endeavour as it launches from Kennedy Space Center.
STS-127 crew members gather near space shuttle Endeavour's hatch to place the mission plaque before launch.
When it comes to sneezing in a spacesuit while in the void of space, it is best to aim well.
That's the advice lead spacewalker David Wolf offered Tuesday while answering one of the questions posted on YouTube for the crew of the space shuttle Endeavor.
"I've done it quite a few times, most recently yesterday," said Wolf, who led the mission's second spacewalk Monday and was set to go on a third spacewalk Wednesday. "You learn in training, and I don't know how to say this, aim well. It can mess up your view and there is no way to clear it."
The YouTube questioners, mostly children and teenagers, had posted their questions well before last week's launch of Endeavour on a 16-day mission to the international space station.
Their posts were played one at a time for commander Mark Polansky, pilot Doug Hurley, Canadian astronaut Julie Payette and Wolf, who took turns answering the questions live, more than 200 miles above Earth.
Other questioners asked the astronauts what they missed most in space (friends and family), what they did in their spare time (look out the window) and what would happen if the shuttle or space station flew into a black hole (don't know).
There are currently 13 crew members at the space station — seven visiting from the shuttle and six living at the station.
The YouTube questions were the latest effort by NASA to embrace social media. Polansky has a Twitter account with more than 37,500 followers, and since the mission began last Wednesday, Polansky has tweeted regularly with the help of workers at the Johnson Space Center who actually post his messages.
Last May, under the moniker Astro_Mike, Astronaut Mike Massimino became the first person to tweet from space during space shuttle Atlantis' repair mission to the Hubble Space Telescope.
While Wolf and astronaut Christopher Cassidy prepared for Wednesday's spacewalk, other crew members used robotic arms Tuesday to move a storage pallet holding equipment for three experiments from the belly of the docked space shuttle Endeavour to the outside of the orbiting outpost's Japanese-made lab.
Endeavour's seven astronauts had some rare off-duty hours Tuesday afternoon, when they had the opportunity to do nothing but look out the window.