Commercial Resupply Services (CRS) are a series of flights awarded by NASA for the delivery of cargo and supplies to the International Space Station.The first CRS contracts were signed in 2008 and awarded $1.6 billion to SpaceX for twelve cargo Dragon and $1.9 billion to Orbital Sciences for eight Cygnus flights, covering deliveries to 2016. The Falcon 9 and Antares rockets were also developed under the CRS program to deliver cargo spacecraft to the ISS.
The National Aeronautics and Space Administration is an independent agency of the executive branch of the United States federal government responsible for the civilian space program, as well as aeronautics and aerospace research. NASA have many launch facilities but most are inactive. The most commonly used pad will be LC-39B at Kennedy Space Center in Florida.
Space Exploration Technologies Corp., known as SpaceX, is an American aerospace manufacturer and space transport services company headquartered in Hawthorne, California. It was founded in 2002 by entrepreneur Elon Musk with the goal of reducing space transportation costs and enabling the colonization of Mars. SpaceX has many pads, on the East Coast of the US they own SLC-40 at Cape Canaveral and LC-39A at the Kennedy Space Center for their lower inclination launches. They also own SLC-4E at Vandenberg, California for their high inclination launches. Another site is also being developed at Boca Chica, Texas.
Northrup Grumman Innovation Systems designs, builds and delivers space, defence and aviation-related systems to customers around the world. They aquired Orbital ATK in 2018 along with its launchers and ongoing missions. Antares launches from Wallops in Virginia. Minotaur has many launch sites, with the most active now being Cape Canaveral and Vandenberg. Pegasus is an air launched vehicle from an aircraft and so has many launch locations.
Sierra Nevada Corporation (SNC) is an American, privately held aerospace and national security contractor specializing in aircraft modification and integration, high performance space components and systems, and commercial solutions. The company contracts with the United States Armed Forces, NASA and private spaceflight companies.
Representatives from NASA’s International Space Station Program, SpaceX, and the U.S. Air Force’s 45th Space Wing will host a Prelaunch news conference detailing information about the CRS-21 Mission.