entry into the fast-growing Geosynchronous (GEO) communications satellite market. In 2010, Orbital acquired the Gilbert, Arizona-based satellite development and manufacturing unit from General Dynamics (General Dynamics Advanced Information Systems, formerly Spectrum Astro) to complement its main satellite manufacturing facility in Dulles, Virginia. Merger On 29 April 2014, Orbital Sciences announced that it had entered into a definitive agreement with Alliant Techsystems to combine Orbital and ATK's Aerospace and Defense (A&D) Groups to create a US$4.5 billion (combined calendar year 2013 annual revenue), 13000-person company. The new company was called Orbital ATK, Inc. On 18 September 2017, Northrop Grumman announced plans to purchase Orbital ATK for US$7.8 billion in cash plus assumption of US$1.4 billion in debt. Orbital ATK shareholders approved the buyout on 29 November 2017. The Federal Trade Commission (FTC) approved the acquisition with conditions on 5 June 2018, and one day later, Orbital ATK were absorbed and became Northrop Grumman Innovation Systems. Business groups Space Systems Group (SSG) Orbital was a provider of small- to medium-class satellites. Since the company's founding in 1982, Orbital has delivered 150 spacecraft to commercial, military and civil customers worldwide. To date, these spacecraft have amassed well over 1000 years of on-orbit operations. The communications and imaging satellites developed by Orbital are smaller and more affordable. The geosynchronous orbit (GEO) communications satellites provide commercial satellite services such as direct-to-home digital television, business data transmission, cable program distribution and wireless communications. In addition, Orbital also provides constellations of low Earth orbit communications satellites such as the 35-satellite ORBCOMM data communications network, and the 81 spacecraft (integration and test) for the IridiumNEXT constellation. Earth imagery and high resolution digital imaging satellites such as the OrbView series are also developed and manufactured by Orbital. The science and environmental satellites developed by Orbital perform scientific research, carry out deep space exploration (e.g. Dawn spacecraft), conduct remote sensing missions (e.g. Landsat 4, 5 and 8), and demonstrate new space technologies. In the last 10 years, Orbital has built more scientific and environmental monitoring satellites for NASA than any other company. Launch Systems Group (LSG) Orbital's space launch vehicles are considered the industry standard for boosting small payloads to orbit. The Pegasus launch vehicle is launched from the company's L-1011 carrier aircraft, Stargazer and has proven to be the industry's small space launch workhorse, having conducted 40 missions from six different launch sites worldwide since 1990. The Minotaur ground-launched