Space Exploration Technologies (SpaceX)

SpaceX has developed its Dragon (cargo) vehicle to launch on their Falcon 9 launch vehicle. The company is also developing a manned version of the same vehicle. An unmanned Dragon cargo vehicle was successfully flown to the ISS in 2012, becoming the first commercial vehicle to attach itself to the ISS. The Dragon spacecraft can handle both pressurized (up to 14 m3 or 55 ft3) and unpressurized (up to 10 m3 or 39 ft3) payloads in a fully recoverable capsule with a combined capsule and support trunk up-mass of 2,7201b (6,000 kg) or 1,3601b (3,000 kg) for the down-mass of only the capsule. It has an impressive mission duration capabil­ity of between one week and two years. The first manned flight is planned for 2015 and the vehicle is designed to carry up to seven astronauts on a wide variety of missions.

Orbital Sciences Corporation (Orbital)

Orbital is developing an unmanned cargo vehicle called Cygnus that will be launched on an Antares launch vehicle. This will be an advanced maneuvering spacecraft designed to support cargo delivery services and is planned to fly eight missions over a 2yr period (currently 2013 to 2015), delivering approximately 20,000 kg (44,000 lb) of cargo to the ISS and then disposing of unwanted waste in a destructive reentry. Using proven technology, the vehicle comprises a common service module and a pressurized cargo module. The pressurized module is based on the Multi-Purpose Logistics Module developed by Thales Alenia Space.