Orbital ATK is one of two private companies that currently hold a contract with NASA to fly unmanned cargo missions to the International Space Station. The company was formed in a merger of Orbital Sciences Corp. and Alliant Techsystems (ATK). 

Orbital Sciences specialized in launching small satellites and was best known for launching the Cygnus cargo spacecraft to the ISS. ATK was best known for creating solid rocket boosters for the space shuttles. Since the February 2015 merger, Orbital ATK works on flight systems, defense systems and space systems.

The Dulles, Va.-based company's $1.9 billion deal with the space agency requires it to fly eight unmanned cargo missions to the International Space Station using its Antares rocket and Cygnus capsule. Pre-merger, Orbital Sciences had a setback when one of its spacecraft exploded just after launch on Oct. 28, 2014, likely due to suspect Russian engines in Orbital's Antares rocket. Flights resumed on a United Launch Alliance Atlas V rocket in December 2015. A March 2016 cargo delivery marked the final launch on a ULA rocket. 

ATK's rocket boosters safely delivered the space shuttles to orbit, except for one catastrophic failure in 1986 that led to the death of seven astronauts on board space shuttle Challenger. ATK made design changes to the boosters in the wake of the disaster.

ATK was one of the contractors working on NASA's Constellation program, which aimed to carry astronauts to the moon and beyond. ATK constructed the first stage of the Ares 1 rocket that would take the astronauts aloft. The program, which was conceived under President George W. Bush, was cancelled shortly after President Barack Obama took office. NASA is now working toward a "flexible destination" program that could include destinations such as asteroids, although NASA is now pitching most of its human work as the groundwork of an eventual "Journey to Mars" in the 2030s.

Orbital Sciences' formal relationship with NASA began in 1983 when the firm signed an agreement to build a Transfer Orbit Stage vehicle that was eventually used during a launch of the space shuttle Discovery. [See Photos of Orbital's Cygnus and Antares]

By 1991, officials from Orbital signed an $80 million deal allowing NASA to use the company's Pegasus rocket to deliver small payloads into orbit. Pegasus — a winged three-stage rocket designed to fly to low-Earth orbit — was the first privately developed space launch vehicle.

In the past, the aerospace firm had also signed deals with the U.S. Air Force, Japan's Broadcasting Satellite System Corporation and the Defense Advanced Research Projects Agency.

The Orbital Sciences Antares rocket is seen just before exploding during launch on Oct. 28, 2014 during a failed launch attempt from NASA's Wallops Flight Facility on Wallops Island, Virginia.
The Orbital Sciences Antares rocket is seen just before exploding during launch on Oct. 28, 2014 during a failed launch attempt from NASA's Wallops Flight Facility on Wallops Island, Virginia.
Credit: NASA TV

With mergers a common practice in the aerospace business, Orbital Sciences Corp. and Alliant Techsystems chose to pursue that option in 2014, finalizing the process in February 2015. The companies had previously worked together in many capacities, including Orbital's Antares rocket, for which ATK provided solid rocket motors for the upper stage. 

"This merger-of-equals combination of Orbital and ATK Aerospace and Defense brings together two of the space and defense industry's most innovative developers and cost-efficient manufacturers who have worked closely together for over 25 years," said then-Orbital CEO David Thompson in a 2014 press release. Thompson was later appointed the first CEO of Orbital ATK.

With the merger, ATK's aerospace and defense groups were merged with Orbital. ATK's sporting group was spun off into a separate company called Vista Outdoor.

Orbital's unmanned Cygnus spacecraft is designed to deliver pressurized crew supplies, scientific experiments and other unpressurized cargo to the space station. Cygnus comes equipped with two sets of solar arrays on either side of the service module. The arrays power the command control and communications hardware of the robotic capsule once launched and deployed.

The capsule's design draws on previously tested spaceflight technology crafted by Orbital's engineers. The spacecraft's designers incorporated avionics systems from LEOStar and GEOStar satellites into Cygnus and the power and propulsion systems used by GEOStar as well.

In two successful flights, Cygnus delivered more than 7,940 lbs. (3,600 kilograms) to the space station and re-entered the atmosphere with 6,830 lbs. (3,100 kg) of trash. In the December 2015 launch, an "enhanced Cygnus" craft carried more than 7,700 lbs. (3,500 kg) of supplies up with it — even more than originally planned, due to the additional capacity of the Atlas V, Orbital ATK officials told Space.com. The March 2016 launch carried even more cargo — nearly 7,500 lbs. (3,400 kg), setting a record for an Atlas V rocket, company officials said.

But it is the Antares rocket that the company wants to use in future launches. Orbital's Antares rocket — formerly called the "Taurus II" — is a two-stage launch vehicle designed to deliver cargo to low-Earth orbit. When upright, the rocket is 131 feet (40 m) tall, and the rocket's dual AJ26 rocket engines are designed to provide 680,000 pounds of thrust. Antares' first test launch occurred on April 18, 2013.

An Antares rocket exploded moments after launching from a pad at NASA's Wallops Flight Facility in Virginia. The launch was expected to deliver a Cygnus spacecraft to the International Space Station. However, the massive failure destroyed the unmanned space probe. Antares performed four successful flights before the failure on Oct. 28, 2014.

On Nov. 5, 2014, Orbital representatives announced that they were likely planning to discontinue the use of the AJ26 engines for the next generation Antares rocket. 

Orbital has conducted dozens of launches for the U.S. Missile Defense Agency, the Air Force, the Army and the Navy to enhance missile defense systems in the country. The firm also manufactures and supplies "interceptor boosters" to intercept possible missiles launched against the United States. Orbital also builds target vehicles that can be used in simulations designed to test the efficacy of the missile defense systems.

Orbital is not the only company that has a cargo deal with NASA. The California-based commercial spaceflight firm SpaceX has successfully flown several of its 12 contracted unmanned cargo missions to the space station under its $1.6 billion contract with the space agency, although it also experienced a catastrophic failure. 

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