Documents filed with the US Securities and Exchange Commission (SEC) reveal that Orbital Sciences' development costs for the Antares rocket are estimated at $472 million.

"Under the COTS agreement, as amended, as of March 31, 2012, NASA has agreed to pay us $288 million in cash milestone payments, partially funding our program costs which are currently estimated to be approximately $472 million," reads the 10-Q. "We expect to complete this program in the second half of 2012."

The estimated cost is higher than the fourth quarter, 2011 filing, which stated that the estimated development costs totaled $458 million.

The estimated development costs for Antares are relatively low for a new rocket programme. Though development costs are tightly held competitive secrets, programmes for similar rockets routinely reach into the billions of dollars. High development costs and technical risk form two of the major barriers to entry for companies building new rockets, hence the industry's heavy use of 'heritage hardware' and evolutionary design families.

Antares uses pre-existing solid rocket motors, including the Aerojet AJ-26 first stage, a retooled version of the Ukrainian NK-33, and the Castor 30 second stage, developed from the retired Peacekeeper intercontinental ballistic missile (ICBM) first stage.

 Orbital Sciences Taurus II rocket,

 ©Orbital Sciences

Antares is scheduled to make its first flight under NASA's commercial orbital transportation services (COTS) contract, which could see a total of $288 million given to Orbital for hitting milestones in programme development. Antares' first launch, with a payload mass simulating human-capable Cygnus capsule, is scheduled later in 2012. The launch pad at Wallops Island, Virginia, is not yet complete and ready to accommodate a launch.

Orbital Sciences did not immediately return requests for comment.

Source: Flight International