Cygnus OA-4
An Atlas V 401 launches the S.S. Deke Slayton II. | |
| Names | CRS OA-4 CRS Orb-4 (2008–2015) Orbital-4 (2008–2015) |
|---|---|
| Mission type | ISS resupply |
| Operator | Orbital ATK |
| COSPAR ID | 2015-072A |
| SATCAT no. | 41101 |
| Mission duration | 75 days, 18 hours, 15 minutes |
| Spacecraft properties | |
| Spacecraft | S.S. Deke Slayton II |
| Spacecraft type | Enhanced Cygnus |
| Manufacturer |
|
| Launch mass | 7,492 kg (16,517 lb) |
| Payload mass | 3,513 kg (7,745 lb) |
| Start of mission | |
| Launch date | 6 December 2015, 21:44:57 UTC (4:44:57 pm EST) |
| Rocket | Atlas V 401 (AV-061) |
| Launch site | Cape Canaveral, SLC‑41 |
| Contractor | United Launch Alliance |
| End of mission | |
| Disposal | Deorbited |
| Decay date | 20 February 2016, 16:00 UTC |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Low Earth orbit |
| Inclination | 51.64° |
| Berthing at ISS | |
| Berthing port | Unity nadir |
| RMS capture | 9 December 2015, 11:19 UTC |
| Berthing date | 9 December 2015, 14:26 UTC |
| Unberthing date | 19 February 2016, 10:38 UTC |
| RMS release | 19 February 2016, 12:26 UTC |
| Time berthed | 71 days, 20 hours, 12 minutes |
NASA insignia | |
OA-4, previously known as Orbital-4, was the fourth successful flight of the Orbital ATK uncrewed resupply spacecraft Cygnus and its third flight to the International Space Station (ISS) under the Commercial Resupply Services (CRS-1) contract with NASA. With the Antares launch vehicle undergoing a redesign following its failure during the Orb-3 launch, OA-4 was launched by an Atlas V launch vehicle. Following three launch delays due to inclement weather beginning on 3 December 2015, OA-4 was launched at 21:44:57 UTC on 6 December 2015. With a liftoff weight of 7,492 kg (16,517 lb), OA-4 became the heaviest payload ever launched on an Atlas V. The spacecraft rendezvoused with and was berthed to the ISS on 9 December 2015. It was released on 19 February 2016 after 72 days at the International Space Station. Deorbit occurred on 20 February 2016 at approximately 16:00 UTC.