Commercial Resupply Services (CRS) are a series of flights awarded byNASA for the delivery of cargo and supplies to theInternational Space Station (ISS) on commercially operated spacecraft.[1]
The first phase of CRS contracts (CRS-1) were signed in 2008 and awarded $1.6 billion toSpaceX for twelveDragon 1 and $1.9 billion toOrbital Sciences[note 1] for eightCygnus flights, covering deliveries to 2016. The first operational resupply missions were flown by SpaceX in 2012 (CRS SpX-1)[2] and Orbital in 2014 (CRS Orb-1).[3] In 2015, NASA extended CRS-1 to twenty flights for SpaceX and twelve flights forOrbital ATK.[note 1][4][5]
A second phase of contracts (CRS-2) was solicited in 2014. CRS-2 contracts were awarded in January 2016 to Orbital ATK's continued use ofCygnus,Sierra Nevada Corporation's newDream Chaser, and SpaceX's newDragon 2, for cargo transport flights beginning in 2019 and expected to last through 2024.
The first flight contracted by NASA,COTS Demo Flight 1, took place on December 8, 2010, demonstrating a Dragon capsule's ability to remain in orbit, receive and respond to ground commands, and communicate with NASA'sTracking and Data Relay Satellite System. On August 15, 2011, SpaceX announced that NASA had combined the objectives of theCOTS Demo Flight 2 and following Flight 3 into a single mission.[7][8] The rescopedCOTS Demo Flight 2 successfully launched on May 22, 2012, delivering cargo to the ISS. The spacecraft reentered on May 31, landed in the Pacific Ocean, and was recovered, completing CRS certification requirements.[9][10]
On December 23, 2008, NASA announced the initial awarding of cargo contracts - twelve flights toSpaceX and eight flights toOrbital Sciences Corporation.[16]PlanetSpace, which was not selected, submitted a protest to theGovernment Accountability Office.[17] On April 22, 2009, the GAO publicly released its decision to deny the protest, allowing the program to continue.[18]
CRS SpX-7: attempted on June 28, 2015. Launch failure 139 seconds after lift-off,IDA-1 destroyed. Investigation traced the accident to the failure of a strut inside the second stage's liquid-oxygen tank. NASA concluded that the most probable cause of the strut failure was a design error: instead of using a stainless-steel eye bolt made of aerospace-grade material, SpaceX chose an industrial-grade material without adequate screening and testing and overlooked the recommended safety margin.[22]
CRS Orb-3: October 28, 2014 - launch failure, food and care packages for the crew, parts, experiments, and the Arkyd-3 Flight Test (Non-optical) Satellite from Planetary Resources lost.
Following the failure, theAntares rocket was upgraded to the 230 series which used newly builtRD-181 first-stage engines to provide greater payload performance and increased reliability.[28] The next two spacecraft were launched on theAtlas V. With the switch to more powerful launch vehicles and the introduction of a larger Enhanced Cygnus, enabled Orbital ATK to cover their initial CRS contracted payload obligation by OA-7.[29][30]
During August 2015, Orbital ATK disclosed that they had received an extension of the resupply program for four extra missions. These flights enable NASA to cover ISS resupply needs until CRS-2 begins.[29]
NASA began a formal process to initiate Phase 2 of the Commercial Resupply Services, or CRS-2, in early 2014.[36] Later that year, an "Industry Day" was held in Houston, with seven high-level requirements disclosed to interested parties.[37]
The contracts were expected to include a variety of requirements:[37]
delivery of approximately 14,000 to 17,000 kg (31,000 to 37,000 lb) per year 55 to 70 m3 (1,900 to 2,500 cu ft) of pressurized cargo in four or five transport trips
delivery of 24–30 powered lockers per year, requiring continuous power of up to 120 watts at 28 volts, cooling, and two-way communications
delivery of approximately 1,500 to 4,000 kg (3,300 to 8,800 lb) per year of unpressurized cargo, consisting of 3 to 8 items, each item requiring continuous power of up to 250 watts at 28 volts, cooling, and two-way communications
return/disposal of approximately 14,000 to 17,000 kg (31,000 to 37,000 lb) per year 55 to 70 m3 (1,900 to 2,500 cu ft) of pressurized cargo
disposal of 1,500 to 4,000 kg (3,300 to 8,800 lb) per year of unpressurized cargo, consisting of 3 to 8 items
SNC's proposal would use a cargo version of itsDream Chaser crew vehicle, the 'Dream Chaser Cargo System'. The proposed cargo Dream Chaser included an additional expendable cargo module for uplift and trash disposal. Downmass would only be provided via the Dream Chaser spaceplane itself.[38] Boeing's proposal likewise used a cargo version of itsCST-100 crew vehicle.[39][40]
Three companies were awarded contracts on January 14, 2016.[43][37]Sierra Nevada Corporation'sDream Chaser, theSpaceXDragon 2, and Orbital ATK[note 1]Cygnus were selected, each for a minimum of six launches.[43][44] The maximum potential value of all the contracts was indicated to be $14 billion, but the minimum value is considerably less. CRS-2 launches commenced in 2019 and will extend to at least 2024.
Three more CRS-2 missions for Dragon 2 covering up to CRS-29 were announced in December 2020.[45][46]
When NASA issued the Commercial Resupply Services phase 2 (CRS-2) request for proposal (RFP) in September 2014, it received interest from five companies: Lockheed Martin, Boeing, Orbital ATK, Sierra Nevada, and SpaceX. NASA made a competitive range determination to remove Boeing and Lockheed Martin.
Orbital ATK (later purchased by Northrop Grumman), Sierra Nevada, and SpaceX were awarded CRS-2 contracts in January 2016 with initial task orders awarded in June 2016. Each of the three companies is guaranteed at least six cargo missions under the CRS-2 contract. As of December 2017, NASA had awarded $2.6 billion on three contracts with a combined, not-to-exceed value of $14 billion. NASA officials explained that selecting three companies rather than two for CRS-2 increases cargo capabilities and ensures more redundancy in the event of a contractor failure or schedule delay.The CRS-2 flights commenced in November 2019 with the launch ofCygnus NG-12 mission.[47]
As a result Russia's invasion of Ukraine, Northrop Grumman was left with only two remaining Antares 230+ launch vehicles which were used for the CRS NG-18 and CRS NG-19 missions. Northrop Grumman acquired four flights from SpaceX with the Falcon 9 rocket while a replacement first stage and its engine are developed for its Antares 330 rocket.[50][51]
Northrop Grumman plans to launch further missions using the newAntares 300 series (Antares 330) rockets with booster stage and engines developed byFirefly Aerospace.[50][54]
^abcdOrbital Sciences was awarded a CRS contract in 2008. In 2015, Orbital Sciences becameOrbital ATK through a business merger. Orbital ATK was awarded a CRS-2 contract in 2016. In 2018, Orbital ATK was acquired byNorthrop Grumman.
^Cygnus was owned and operated by Orbital Sciences for missions CRS Orb-1 to CRS Orb-3.
^Cygnus was owned and operated by Orbital ATK for missions CRS OA-4 to CRS OA-9E.
^Cygnus has been owned and operated by Northrop Grumman since mission NG-10.
^NASA’s SpaceX Crew-9 Post-Splashdown News Conference. March 18, 2025. Event occurs at 1:04:24. RetrievedMarch 18, 2025.There is a particular SpaceX cargo flight, CRS-33, that has the ability to do some re-boosts for the space station and that needs to fly in than late August/early September timeframe, so we moved the handover up. The boost trunk, as we call it, will be there for a large part of the fall timeframe.
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