Commercial Orbital Transportation Services in the context of Fixed-price contract

Space Exploration Technologies Corp., commonly known as SpaceX, is a private American aerospace company and space transportation company headquartered at the Starbase development site in Starbase, Texas. Since its founding in 2002, the company has made numerous advances in rocket propulsion, reusable launch vehicles, human spaceflight and satellite constellation technology. As of 2025, SpaceX is the world's dominant space launch provider, its launch cadence eclipsing all others, including private competitors and national programs like the Chinese space program. SpaceX, NASA, and the United States Armed Forces work closely together by means of governmental contracts.

SpaceX was founded by Elon Musk in 2002 with a vision of decreasing the costs of space launches, paving the way to a self-sustaining colony on Mars. In 2008, Falcon 1 successfully launched into orbit after three failed launch attempts. The company then moved towards the development of the larger Falcon 9 rocket and the Dragon 1 capsule to satisfy NASA's COTS contracts for deliveries to the International Space Station. By 2012, SpaceX finished all COTS test flights and began delivering Commercial Resupply Services missions to the International Space Station. Also around that time, SpaceX started developing hardware to make the Falcon 9 first stage reusable. The company demonstrated the first successful first-stage landing in 2015 and re-launch of the first stage in 2017. Falcon Heavy, built from three Falcon 9 boosters, first flew in 2018 after a more than decade-long development process. As of May 2025, the company's Falcon 9 rockets have landed and flown again more than 450 times, reaching 1–3 launches a week.

Cygnus is an expendable American uncrewed cargo spacecraft developed for International Space Station (ISS) resupply missions. It was originally built by Orbital Sciences Corporation with financial support from NASA under the Commercial Orbital Transportation Services (COTS) program. The spacecraft consists of a pressurized cargo module—based largely on the Multi-Purpose Logistics Module and built by Thales Alenia Space—paired with a service module derived from Orbital's GEOStar, a satellite bus. Following a successful demonstration flight in 2013, Orbital was awarded a Commercial Resupply Services (CRS) contract.

Over time, Cygnus has been upgraded to increase its size and capabilities. The Enhanced Cygnus variant debuted in 2015, and the further enlarged Cygnus XL entered service in 2025. Features added over time include reboost capability to raise the ISS orbit, the ability to support late cargo loading shortly before launch, and the option to conduct secondary missions after undocking. Each mission ends with a controlled destructive reentry, which also provides a means of disposing of waste generated aboard the station. Alongside Cygnus, other ISS resupply spacecraft have included the Russian Progress, the European Automated Transfer Vehicle, the Japanese H-II Transfer Vehicle, and the American SpaceX Dragon.