This article outlines notable events occurring in 2005 in spaceflight, including major launches and EVAs. 2005 saw Iran launch its first satellite.

Pegasus is an air-launched multistage rocket developed by Orbital Sciences Corporation (OSC) and later built and launched by Northrop Grumman. Pegasus is the world's first privately developed orbital launch vehicle. Capable of carrying small payloads of up to 443 kg (977 lb) into low Earth orbit, Pegasus first flew in 1990 and remained active as of 2021. The vehicle consists of three solid propellant stages and an optional monopropellant fourth stage. Pegasus is released from its carrier aircraft at approximately 12,000 m (39,000 ft) using a first stage wing and a tail to provide lift and altitude control while in the atmosphere. The first stage does not have a thrust vector control (TVC) system.