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Cygnus CRS OA-4, also known as Orbital ATK CRS-4 and CRS Orb-4, was the fourth successful flight of the Orbital ATK uncrewed resupply spacecraft Cygnus and its third flight to the International Space Station under the Commercial Resupply Services contract with NASA.[8][9] With the Antares rocket undergoing a redesign following its failure during the Orb-3 launch, OA-4 was launched by an Atlas V rocket. Following three launch delays due to inclement weather beginning on 3 December 2015, OA-4 was launched at 21:44 UTC on 6 December 2015. With a liftoff weight of 7,492 kilograms (16,517 lb), OA-4 became the heaviest payload ever launched on an Atlas V.[10] The spacecraft rendezvoused with and was berthed to the ISS on 9 December 2015.[5] It was released on 19 February 2016 after 72 days at the station.[7] Deorbit occurred on 20 February at approximately 16:00 UTC.[3]

Cygnus CRS OA-4
ISS-45 Cygnus 5 approaching the ISS (2).jpg
The CRS OA-4 Cygnus spacecraft approaches the ISS
Mission typeISS resupply
OperatorOrbital ATK
COSPAR ID2015-072A
SATCAT no.41101
Mission durationFinal: 75 days, 18 hours, 15 minutes
Spacecraft properties
SpacecraftS.S. Deke Slayton II
Spacecraft typeEnhanced Cygnus[1]
ManufacturerOrbital ATK
Thales Alenia Space
Launch mass7,492 kg (16,517 lb)[2]
Payload mass3,513 kg (7,745 lb)[2]
Start of mission
Launch date6 December 2015, 21:44:57 (2015-12-06UTC21:44:57) UTC
RocketAtlas V 401 (AV-061)
Launch siteCape Canaveral SLC-41
ContractorUnited Launch Alliance
End of mission
Decay date20 February 2016, 16:00 (2016-02-20UTC17) UTC[3]
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Semi-major axis6,781.5 km (4,213.8 mi)
Perigee altitude397.9 km (247.2 mi)
Apogee altitude408.8 km (254.0 mi)
Inclination51.64 degrees
Epoch9 December 2015, 05:44:31 UTC[4]
Berthing at International Space Station
Berthing portUnity nadir
RMS capture9 December 2015, 11:19 UTC[5]
Berthing date9 December 2015, 14:26 UTC[5]
Unberthing date19 February 2016, 10:38 UTC[6]
RMS release19 February 2016, 12:26 UTC[7]
Time berthed71 days, 20 hours, 12 minutes
Orbital Sciences CRS Flight 4 Patch.png
NASA OA-4 mission patch  


Atlas V rocket with Cygnus on Pad 41

OA-4 was the fourth of eight flights by Orbital ATK under the Commercial Resupply Services contract with NASA and the inaugural flight of the larger Enhanced Cygnus PCM. The mission was originally scheduled for 1 April 2015.[11] The Atlas 5 rocket launched in the 401 vehicle configuration with a four-meter fairing, no solid rocket boosters and a single-engine Centaur upper stage.[8]

In an Orbital ATK tradition, this Cygnus spacecraft was named Deke Slayton II after one of NASA's original Mercury Seven astronauts and Director of Flight Operations, who died in 1993. This spacecraft reuses the name Deke Slayton, originally applied to the Orb-3 spacecraft which was lost in an Antares rocket explosion in October 2014.[12]


An astronaut captured this image of the spacecraft during launch with the Atlas engines still firing.

The mission was the first flight of the enhanced variant of Orbital ATK's Cygnus spacecraft, capable of delivering more than 7,700 pounds of essential crew supplies, equipment and scientific experiments to the station.

Total cargo: 3,349 kg (7,383 lb)[5][13]

  • Crew supplies: 1,181 kg (2,604 lb)
    • Crew care packages
    • Crew provisions
    • Food
  • Vehicle Hardware: 1,007 kg (2,220 lb)
    • Crew health care system hardware
    • Environment control and life-support equipment
    • Electrical power system hardware
    • Extravehicular robotics equipment
    • Flight crew equipment
    • PL facility
    • Structural & mechanical equipment
    • Internal thermal control system hardware
  • Science Investigations: 847 kg (1,867 lb)
    • A new life science facility called the Space Automated Bio Lab (SABL) that will support studies on cell cultures, bacteria, and other micro-organisms;
    • A microsatellite deployer and the second microsatellite to be deployed from the space station;
    • The NASA LONESTAR experimental payload consisting of the AggieSat4 and Bevo-2 satellites[14]
      • The AggieSat4 satellite, built by engineering students at Texas A&M University, deploys the smaller Bevo-2 CubeSat stored inside of it;
      • The Bevo-2 CubeSat, designed and built by engineering and computer science students at the University of Texas at Austin;
    • Experiments that will study the behavior of gases and liquids and clarify the thermo-physical properties of molten steel; and
    • Evaluations of flame-resistant textiles.
  • Computer Resources: 87 kg (192 lb)
    • Command and data handling
    • Photo and TV equipment
  • Spacewalk Equipment: 227 kg (500 lb)

Total cargo with packing material: 3,513 kg (7,745 lb)


  1. ^ Bergin, Chris (22 February 2012). "Space industry giants Orbital upbeat ahead of Antares debut". NASA Spaceflight. Retrieved 29 March 2012.
  2. ^ a b Ray, Justin (29 November 2015). "International Space Station and crew awaiting Atlas 5 launch of Cygnus". Spaceflight Now. Retrieved 2 December 2015.
  3. ^ a b "At ~11 am ET today..." Orbital ATK. 20 February 2016. Retrieved 20 February 2016.
  4. ^ "Cygnus ORB-4". 9 December 2015. Retrieved 9 December 2015.
  5. ^ a b c d Ray, Justin (9 December 2015). "U.S. resupply of space station successfully resumes". Spaceflight Now. Retrieved 9 December 2015.
  6. ^ Evans, Ben (19 February 2016). "As OA-4 Cygnus Departs, Commercial Cargo Providers Prepare for Busy Visiting Vehicle Manifest". AmericaSpace. Retrieved 20 February 2016.
  7. ^ a b Gebhardt, Chris; Bergin, Chris (19 February 2016). "OA-4 Cygnus ends ISS mission with high praise and success". NASA Spaceflight. Retrieved 19 February 2016.
  8. ^ a b "Launch Schedule". Spaceflight Now. Retrieved 26 January 2015.
  9. ^ "International Space Station Flight Schedule". SEDS. 15 May 2013.
  10. ^ Ray, Justin (6 December 2015). "Atlas 5 rocket sends Cygnus in hot pursuit of space station". Spaceflight Now. Retrieved 7 December 2015.
  11. ^ Graham, William; Bergin, Chris (28 October 2014). "Orbital's Antares fails seconds after launch". NASA Spaceflight.
  12. ^ "Orbital ATK's Cargo Delivery Mission to International Space Station Set to Launch". Orbital ATK. 1 December 2015. Archived from the original on 8 December 2015. Retrieved 2 December 2015.
  13. ^ "Orbital ATK CRS-4 Mission Overview" (PDF). NASA. Retrieved 9 December 2015.
  14. ^ "Low Earth Orbiting Navigation Experiment for Spacecraft Testing Autonomous Rendezvous and Docking (LONESTAR)". NASA. Retrieved 12 December 2015.

External linksEdit

  Media related to Cygnus 5 at Wikimedia Commons