A few hours ago the Orbital ATK’s Cygnus spacecraft blasted off atop an Atlas V rocket from Cape Canaveral. After about twenty minutes it successfully separated from the rocket’s last stage and got in route. This is its fourth official mission, Orbital-4 or simply Orb-4 as well as CRS OA-4, to transport supplies to the International Space Station for NASA.

After the failure of the mission Orb-3 caused by the explosion of the Antares rocket on October 28, 2014, the then Orbital Sciences managers began immediately to look for alternatives for their missions. The contract with NASA is worth a lot of money but for this reason also entails considerable obligations. With the Antares rocket grounded for the redesign with new engines, the company purchased at least two launches with Atlas V rockets.

Despite the long list of successful launches, it’s the first time that an Atlas V is used to launch a cargo spacecraft to the International Space Station. This may sound strange but it’s due to the fact that ULA works a lot with the US military and intelligence launching their satellites and when works with NASA so far launched satellites and space probes.

The point of opening to private companies in the launches to the International Space Station was also to stimulate new solutions to lower the cost of the launches and those with the Atlas V are far from cheap. There are no official information on the price Orbital ATK is paying ULA but the plausible figure is something beyond $100 million, a figure significantly higher than the cost of a launch of the Antares rocket.

Because of the delays accumulated in the aftermath of the October 28, 2014, Orbital ATK was able to complete the development of the new version of its Cygnus spacecraft. The company called this Cygnus Deke Slayton II after Kent Donald “Deke” Slayton (1924 – 1993), pilot of airplanes during the Second World War and a pioneer of the American space program with the Mercury missions, of which he was one of the original seven astronauts. The first Cygnus Deke Slayton was the one that was destroyed at the beginning of the Orb-3 mission so it was decided to give the same name to the next one.

The new Cygnus is equipped with bigegr and  more efficient solar panels but above all its internal volume was increased by about 25%. Thanks to the use of new lighter components, it can carry 1,200 kg (about 2,650 lbs) more of cargo. For this reason, the Deke Slayton II carries approximately 3,350 kg (almost 7,400 lbs) of assorted cargo of which nearly 1,200 kg (about 2,650 lbs) are composed of supplies for the crew, about 1,000 kg (about 2,200 lbs) of hardware, almost 850 kg (almost 1,900 lbs) of scientific experiments and the rest of other equipment varied.

The Cygnus spacecraft is due to dock with the International Space Station on Wednesday December 9 shortly after 11 AM UTC. If there are no problems, the next day the crew will open the hatch and can begin unloading the cargo. After a difficult year and more days of waiting due to bad weather which caused a delay of the launch, for Orbital ATK maybe things are returning to normal.

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