The year 2008 contained several significant events in spaceflight, including the first flyby of Mercury by a spacecraft since 1975, the discovery of water ice on Mars by the Phoenix spacecraft, which landed in May, the first Chinese spacewalk in September, the launch of the first Indian Lunar probe in October, and the first successful flight of a privately developed orbital launch vehicle by SpaceX's Falcon 1.

The internationally accepted definition of a spaceflight is any flight which crosses the Kármán line, 100 kilometres above sea level.

Five carrier rockets made their maiden flights in 2008; the Ariane 5ES, Long March 3C, Zenit-3SLB, PSLV-XL, and the operational version of the Falcon 1, with an uprated Merlin-1C engine.

India launched its first Lunar probe, Chandraayan-1, on 22 October, with the spacecraft entering selenocentric orbit on 8 November.

Cassini continued to make flybys of the moons of Saturn, including several close passes of Enceladus, one at a distance of 25 kilometres.

Yi returned to Earth aboard Soyuz TMA-11, which nearly ended in disaster following a separation failure between the descent and service modules, resulting in a ballistic reentry.

March saw the launch of the Jules Verne Automated Transfer Vehicle, an uncrewed European spacecraft which was used to resupply the space station.

Several hours later, on 15 March, the Briz-M engine cut off prematurely during a burn,[10] leaving the satellite in a medium Earth orbit.

Following a small legal dispute,[11] the satellite was sold, and raised to a geosynchronous orbit by its manoeuvring thrusters, at the expense of a large amount of its fuel and hence operational life.

The Trailblazer, PreSat and NanoSail-D satellites were lost in the failure, as was a space burial capsule, containing the remains of several hundred people, including astronaut Gordon Cooper, actor James Doohan, writer and director John Meredyth Lucas and Apollo mission planner Mareta West.

[13] On 16 August, Iran launched a Safir, which though officially successful, was reported to have failed due to a second stage malfunction.

The final launch of the year was conducted on 25 December, by a Proton-M with three GLONASS navigation satellites for the Russian government.