Orbital Sciences Corporation today successfully launched the first of eight Cygnus cargo supply missions to the International Space Station (ISS). Orbital's Antares medium-lift rocket (originally called the Taurus II) carried the Cygnus into an initial orbit of 135 x 175 miles (220 x 280 km), inclined at 51.6 degrees relative to the equator. The Cygnus is flying solo now, with full communications and deployed solar arrays, carrying roughly 2,800 lb (1,300 kg) of cargo toward a January 12 rendezvous and docking with the ISS.

Orbital and SpaceX are currently the only commercial launch services certified to provide Commercial Resupply Services (CRS) for the ISS. Orbital's US$1.9 billion initial contract calls for eight Cygnus launches, delivering cargo at a cost of just under $45,000/lb ($100,000/kg). For these missions, Orbital will deliver items needed for continuation of the ISS program, such as food, clothing, crew supplies, spare parts and equipment, and scientific experiments.

The cost of cargo delivery does not compare well with SpaceX's contract. If NASA chooses to use the full cargo capacity of SpaceX's Dragon spacecraft, as it is with Orbital's Cygnus, SpaceX's $1.6 billion contract for 12 resupply missions results in a cargo delivery cost of less than half the cost ($18,000/lb or $40,000/kg.) Still, having two arrows in the quiver allows for contingency planning.

Today's Cygnus mission was originally delayed by the ISS cooling repairs from December, and then on Tuesday an X-class solar flare aimed directly at Earth made it advisable to further delay the launch to today (Thursday). While the ISS and the Cygnus are hardened against most solar radiation, the Antares launch vehicle is not. As a result, flying in the ejecta from a solar flare of this magnitude could have resulted in failure of the mission.

“It was another excellent launch of Antares, and so far, our first CRS mission is off to a great start with Cygnus operating exactly as anticipated at this early stage of the mission,” said Mr. David W. Thompson, Orbital’s President and Chief Executive Officer. “Our team has put in a lot of hard work to get to the point of performing regular ISS cargo delivery trips for NASA. It’s an exciting day for all of us and I’m looking forward to completing this and our future CRS missions safely and successfully for our NASA customer.”

The following video shows the successful launch.

Source: NASA

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