Commercial cargo heads to station

9 January 2014 Last updated at 19:00 GMT

Cygnus cargo ship heads to space station

Cygnus is put in space by the Antares rocket

The American Orbital Sciences Corporation (OSC) has begun its first commercial re-supply mission to the International Space Station (ISS).

Its Antares rocket carrying the unmanned Cygnus freighter launched from the Wallops base in Virginia at 13:07 local time (18:07 GMT).

Orbit was achieved 10 minutes later.

Cygnus is ferrying just over 1.2 tonnes of supplies to ISS's astronauts, including food, clothing, spare parts, and scientific experiments.

The freighter will raise its orbit over the next couple of days, aiming to park itself just under the station ready for berthing on Sunday.

This procedure involves the ISS astronauts reaching out with a robotic arm, grabbing Cygnus and pulling it into a free port.

It is the second time that OSC has sent a freighter to the ISS. Last September's visit was a demonstration flight. This mission, on the other hand, constitutes the first cargo delivery under a $1.9bn, eight-flight commercial resupply contract that Orbital has with the US space agency (Nasa).

Since the retirement of its space shuttles in 2011, Nasa has sought to contract out routine cargo deliveries to the station, and has financially supported two companies to help them develop the necessary technology.

The other firm is SpaceX of California, which transports freight to the ISS using its Falcon rocket and Dragon supply ship.

Cygnus has significant European involvement. The pressurised vessel that holds the cargo is produced in Turin, Italy, by Thales Alenia Space (TAS).

Its design is based on the logistics modules that TAS produced for the space shuttles when the orbiters ran cargo deliveries to the station.

Vital statistics: How do the spacecraft compare?

• Dragon capsule

  Length: 5.2m
  Diameter: 3.6m
  Upmass: 6t
  The capsule is re-usable
  

• Cygnus capsule

  Length: 6.7m
  Diameter: 3m
  Upmass: 2.7t
  Cygnus is destroyed on re-entry
  

• Falcon 9 launch vehicle

  Design: Two stages
  Mass: 334t
  Thrust at lift-off: 5,000kN
  Fuel: Liquid oxygen/kerosene
  

• Antares launch vehicle

  Design: Two stages
  Mass: 240t
  Thrust at lift-off: 3,000kN
  Fuel: Liquid oxygen/kerosene