After Endeavour's flight there are only 11 shuttle flights before the orbiters are retired.

BBC: NEWS | Science/Nature | Endeavour launched from Florida

During hurricane season, NASA is not allowed to have more than two orbiters in a vertical configuration.

CNN: The space shuttle shell game

NASA's Mariner 9 and two Soviet orbiters arrived in May 1971 to find a global-wide dust storm in progress.

MSN: History littered with failed Mars probes

China has already successfully launched two lunar orbiters in 2007 and 2010.

FORBES: China Unveils Its Five Year Plan For Space

This year, we saw the four surviving orbiters making Earthly journeys -- whether flown or towed -- to new homes at museums and similar attractions.

CNN: Danger meets discovery: Top 10 science stories of 2012

Viking orbiters took over 50, 000 images of the surface of Mars.

NPR: Revisiting the Viking Missions to Mars

"We've had wet orbiters before, " said NASA spokesman Joel Wells.

CNN: Technicians finish toasting shuttle tiles

And the orbiters were developed at the Jet Propulsion Laboratory.

NPR: Revisiting the Viking Missions to Mars

Technicians powered down and "safed" four space shuttle orbiters.

CNN: Attacks prompt widespread closings

Indeed, there's geologic evidence from the rover and from NASA's Mars orbiters that there may once have been a large lake and streams within the basin that Curiosity is driving around in now.

CNN: Have a drink on Mars

Will we be doing orbiters or landers?

BBC: ��Six minutes of terror��