Cygnus (spacecraft)

Country of originUnited StatesOperatorNorthrop GrummanApplicationsISS logistics SpecificationsSpacecraft typeUncrewed cargo vehicleDry massStandard: 1,500 kg (3,300 lb)
Enhanced: 1,800 kg (4,000 lb)^[2]Payload capacityStandard: 2,000 kg (4,400 lb)
Enhanced: 3,500 kg (7,700 lb)^[2]
Mission B: 5,000 kg (11,000 lb)^[3]VolumeStandard: 18.9 m³ (670 cu ft)
Enhanced: 27 m³ (950 cu ft)^[2]
Mission B: 36 m³ (1,300 cu ft)^[4]Power3.5 kWDesign life1 week to 2 years^[1] DimensionsLengthStandard: 5.14 m (16.9 ft)
Enhanced: 6.39 m (21.0 ft)^[2]
Mission B: 7.89 m (25.9 ft)^[3]Diameter3.07 m (10.1 ft)^[2] ProductionStatusIn serviceOn order5Built21Launched20Operational1Retired18Lost1Maiden launch18 September 2013Last launch30 January 2024

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Cygnus is an expendable American cargo spacecraft used for International Space Station (ISS) logistics missions. Cygnus was developed by Orbital Sciences Corporation, partially funded by NASA under the agency's Commercial Orbital Transportation Services (COTS) program. To create Cygnus, Orbital paired the Multi-Purpose Logistics Module, built by Thales Alenia Space and previously used by the Space Shuttle for ISS logistics, with a service module based on Orbital's GEOStar, a satellite bus. After a successful demonstration flight in 2013, Orbital was chosen to receive a Commercial Resupply Services (CRS) contract. A larger Enhanced Cygnus was introduced in 2015. Northrop Grumman later purchased Orbital and has continued to operate Cygnus missions.

Cygnus is typically launched using it's parent company's Antares rocket from the Wallops Flight Facility in Virgina, however it is able to fly on other launch vehicles. After the failure of an Antares rocket destroyed Cygnus CRS Flight 3 and damaged the Wallops facility, two Cygnus missions were launched with Atlas V rockets in 2015 and 2016. Additionally, three Cygnus missions are expected to be launched on the Falcon 9 rocket in 2024 and 2025, operated by CRS competor SpaceX.

In addition to Cygnus, ISS logistics missions have been regularly flown by the Russian Progress spacecraft, the European Automated Transfer Vehicle, the Japanese H-II Transfer Vehicle and the American SpaceX Dragon.

Cygnus is the Latinized Greek word for swan and a northern constellation.

Development

After the retirement of the Space Shuttle was announced, NASA began to look for commercial space launch companies who could fly cargo to the ISS. In early 2006, the agency started its COTS program, where it would help fund the development of cargo spacecraft after a competitive process. SpaceX and Rocketplane Kistler won contracts in the COTS program, however Rocketplane Kistler failed to meet several financial milestones and on 18 October 2007, NASA announced it would terminate its contract and re-award it after a second competition.^[5][6]

Orbital Sciences Corporation participated in this second round, proposing a largely "off-the-shelf" design. The spacecraft, named Cygnus, would be built around a service module based on Orbital's Star Bus, a satellite bus in use since 1997, which would be attached to a pressurized cargo contained built by Thales Alenia Space, based on the Multi-Purpose Logistics Module it previously built for use by the Space Shuttle for ISS logistics.

Cygnus was awarded a COTS contract worth $170 million in February 2008, which was later increased to $288 million. On 23 December 2008, NASA awarded Orbital Sciences a $1.9 billion contract under the Commercial Resupply Services (CRS) program. Under this contract, Orbital Sciences agreed to deliver up to 20 tons of cargo to the ISS through 2016 in eight Cygnus spacecraft flights.^[7]

To propel Cygnus into space, Orbital developed the Antares rocket with the Ukrainian KB Pivdenne design agency. To keep costs low, Antares was equipped with refurbished AJ-26 engines which were originally manufactured in the 1960s and 1970s for the Soviet Moon rocket.

The first Cygnus flight was originally planned to occur in December 2010, but was repeatedly delayed.^[8][9] The Antares made its maiden flight lifting a payload mass simulator to low Earth orbit on April 21, 2013. On September 18, 2013, Antares successfully launched a Cygnus spacecraft on a flight test to rendezvous with the International Space Station.^[10] On 12 January 2014, the first scheduled Cygnus resupply mission arrived at the space station; the capsule carried Christmas presents and fresh fruit for the astronauts. Its arrival was delayed, first by the need to repair the station, and then by frigid weather at the launch site and solar flares that forced postponements.^[10][11]

With the December 2015 launch of Orb CRS-4 on Atlas V, the enhanced version of Cygnus made its debut. While it was planned from the beginning to fly on the fifth mission, the Orb CRS-3 failure and subsequent move to Atlas V meant a delay. However, lessons learned on packing and the extra capabilities of the Atlas allowed payload to be increased to 3,500 kg (7,700 lb).^[12]

Design

The Cygnus spacecraft consists of two basic components: the Service Module (SM) and the Pressurized Cargo Module (PCM).

The SM was based on prior products developed by Orbital including the GEOStar and LEOStar (collectively known as Star Bus) satellite buses and the Dawn spacecraft. It has a gross mass of 1,800 kg (4,000 lb), 32 thrusters for attitude control and one BT-4 main engine^[13] burning 800 kg (1,800 lb) of hypergolic propellants hydrazine and nitrogen tetroxide.^[14][15] The SM is capable of producing up to 4 kW of electrical power via two solar arrays.^[16][17]

The PCM is manufactured by Thales Alenia Space in Turin, Italy. The first "Standard" PCMs had an empty mass of 1,500 kg (3,300 lb)^[18] and a volume of 18 m³ (640 cu ft).^[16]

The fourth and all subsequent Cygnus spacecraft are the "Enhanced" variant.^[17] These have a stretched PCM with an empty mass 1,800 kg (4,000 lb), interior volume increased by 50% to 27 m³ (950 cu ft), and cargo capacity increased by 700 kg (1,500 lb).^[19] To launch the added weight, Orbital used the more powerful Castor 30XL solid-fuel rocket as a second-stage.

During a typical CRS missions, Cygnus maneuvers close to the International Space Station, where the Canadarm2 robotic arm grapples the spacecraft and berths it to a Common Berthing Mechanism on the Harmony module.^[16]

Cygnus does not provide cargo return capability. However, it can be loaded with obsolete equipment and trash which will burn up as the Cygnus makes a destructive reentry.^[20]

An earlier proposed version of Cygnus would have replaced the PCM with the Unpressurized Cargo Module (UCM), based on NASA's ExPRESS Logistics Carrier, and would have been used to transport unpressurized cargo, such as ISS Orbital Replacement Units.^[8][21] Another proposed variant would have replaced the PCM with the Return Cargo Module (RCM), which would have allowed Cygnus to return cargo to Earth.^[8]

In August 2023, Northrop Grumman announced a further enlarged Mission B version of Cygnus, with a 1.5 m (4.9 ft) stretch to the payload module and payload mass increased to 5,000 kg (11,000 lb). This version is expected to enter service with the NG-23 mission in 2025 (the first to use the new Antares 330 launch vehicle).^[3]

Lunar Gateway module variant

In August 2019, NASA decided to sole source its design for the Minimal Habitation Module (Habitation and Logistics Outpost, or HALO) of the Lunar Gateway to Northrop Grumman Innovation Systems, which offered a minimalist 6.1 m (20 ft) by 3 m (9.8 ft) design based directly on the Enhanced Cygnus, as well as a larger 7 m (23 ft) by 4.4 m (14 ft) design^[22][23] having radial docking ports, body-mounted radiators (BMRs), batteries and communications antennas added on the outside. Northrop Grumman Innovation Systems opted to build the minimalist design, which offered the advantage of component compatibility and expedited testing of life support systems on existing Cygnus spacecraft.^[24][25] On 5 June 2020, NASA awarded Northrop Grumman Innovation Systems a $187 million contract to complete the preliminary design of HALO. NASA will sign a separate contract with Northrop for the fabrication of the HALO, and for integration with the Power and Propulsion Element (PPE), being built by Maxar.^[24][25]

Missions

The following list includes only missions that have flown and six planned missions. As of January 2024^[update] two missions are planned to be launched on the Falcon 9 rocket from SLC-40, and three from Wallops on an Antares 330. Cygnus is the only cargo freighter to launch on four different orbital launchers, that is, Antares 100 series, Atlas V, Antares 200 series and Falcon 9 Block 5 rockets.^[26] Each mission is named for a notable member of the Human spaceflight community.

#	Mission	Patch	Payload	Variant	Launch date (UTC)	Rocket	Payload mass	Outcome	Ref.
0	Cygnus Mass Simulator		Cygnus Payload Simulator	—	21 April 2013, 21:00:00	Antares 110	—	Success	[27][28]
			First Antares launch, demonstrated Antares's performance and capability to place its payload on a precise target orbit.[29]
1	Orb-D1 G. David Low		Cygnus 1 Orbital Sciences COTS Demo Flight	Standard	18 September 2013, 14:58:00	Antares 110	1,299 lb (589 kg)	Success	[30][31][27][32]
			First Cygnus mission, first mission to rendezvous with ISS, first mission to berth with ISS, second launch of Antares. Mission Directors: Mike Orlowski (lead) and Ken Peek. The rendezvous between the new Cygnus cargo freighter and the International Space Station was delayed due to a computer data link problem,[33] but the issue was resolved and berthing followed shortly thereafter.[34]
2	Orb-1 C. Gordon Fullerton		Orbital-1	Standard	9 January 2014, 18:07:05	Antares 120	2,780 lb (1,260 kg)	Success	[31][27][35][32]
			First Commercial Resupply Service (CRS) mission for Cygnus, first Antares launch using the Castor 30B upperstage.
3	Orb-2 Janice E. Voss		Orbital Sciences CRS Flight 2	Standard	13 July 2014, 16:52:14	Antares 120	3,293 lb (1,494 kg)	Success	[27][32]
			Second Commercial Resupply Service (CRS) mission for Cygnus.
4	Orb-3 Deke Slayton		Orbital Sciences CRS Flight 3	Standard	28 October 2014, 22:22:38	Antares 130	4,883 lb (2,215 kg)	Failure	[36][32]
			First Antares launch to use Castor 30XL upperstage, delayed due to boat in launch safe zone. Second takeoff attempt suffered a catastrophic anomaly resulting in an explosion shortly after launch. Contents of the cargo included food and care packages for the crew, parts, experiments, and the Arkyd-3 Flight Test (Non-optical) Satellite from Planetary Resources.
5	OA-4 Deke Slayton II		Orbital ATK CRS Flight 4	Enhanced	6 December 2015, 21:44:57	Atlas V 401	7,746 lb (3,514 kg)	Success	[37][38][32]
			First Enhanced Cygnus mission; Orbital Sciences contracted with United Launch Alliance to launch this Cygnus on an Atlas V rocket from Cape Canaveral Air Force Station.
6	OA-6 Rick Husband		Orbital ATK CRS Flight 6	Enhanced	23 March 2016, 03:05:52	Atlas V 401	7,758 lb (3,519 kg)	Success	[37][39][38][40][32]
			Second mission to fly on an Atlas V. Orbital Sciences had an option with United Launch Alliance to conduct a third Cygnus launch on an Atlas V rocket if necessary.
7	OA-5 Alan Poindexter		Orbital ATK CRS Flight 5	Enhanced	17 October 2016, 23:45:36	Antares 230	5,163 lb (2,342 kg)	Success	[41][42][43]
			Successful rendezvous was achieved on 23 October 2016 at 14:53 UTC.
8	OA-7 John Glenn		Orbital ATK CRS Flight 7	Enhanced	18 April 2017, 15:11:26	Atlas V 401	7,443 lb (3,376 kg)	Success	[44][45][39][38][40][32]
9	OA-8E Gene Cernan		Orbital ATK CRS Flight 8	Enhanced	12 November 2017, 12:19:51	Antares 230	7,359 lb (3,338 kg)	Success	[46][45][39][38][40]
			11 November 2017, launch was scrubbed just before launch when a general aviation aircraft entered the hazard zone and did not respond to calls.[47]
10	OA-9E J.R. Thompson		Orbital ATK CRS Flight 9	Enhanced	21 May 2018, 08:44:06	Antares 230	7,385 lb (3,350 kg)	Success	[48][49]
			It became the first time a commercial vehicle performed ISS reboosting when, at 20:25 UTC on July 10, 2018, Cygnus's main engine was fired for about 50 seconds. Although just a test, it raised the altitude by about 295 feet, according to NASA.[50]
11	NG-10 John Young		Northrop Grumman CRS Flight 10	Enhanced	17 November 2018, 09:01:31	Antares 230	7,386 lb (3,350 kg)	Success	[51][52]
12	NG-11 Roger Chaffee		Northrop Grumman CRS Flight 11	Enhanced	17 April 2019, 20:46:07	Antares 230	7,575 lb (3,436 kg)	Success	[53]
13	NG-12 Alan Bean		Northrop Grumman CRS Flight 12	Enhanced	2 November 2019, 13:59:47	Antares 230+	8,221 lb (3,729 kg)	Success
14	NG-13 Robert H. Lawrence		Northrop Grumman CRS Flight 13	Enhanced	15 February 2020, 20:21:01	Antares 230+	8,009 lb (3,633 kg)	Success	[54]
			9 February 2020 launch attempt scrubbed due to a ground support issue.[55]
15	NG-14 Kalpana Chawla		Northrop Grumman CRS Flight 14	Enhanced	3 October 2020, 01:16:14	Antares 230+	7,624 lb (3,458 kg)	Success	[56]
			1 October 2020 launch attempt delayed due to boat in range,[57] later scrubbed due to a ground support issue.[58]
16	NG-15 Katherine Johnson		Northrop Grumman CRS Flight 15	Enhanced	20 February 2021, 17:36:50	Antares 230+	8,400 lb (3,800 kg)	Success
17	NG-16 Ellison Onizuka		Northrop Grumman CRS Flight 16	Enhanced	10 August 2021, 22:01:05	Antares 230+	8,208 lb (3,723 kg)	Success	[59]
18	NG-17 Piers Sellers		Northrop Grumman CRS Flight 17	Enhanced	19 February 2022, 17:40:03	Antares 230+	8,049 lb (3,651 kg)	Success
			Performed the first operational reboost of ISS by a commercial vehicle on 25 June 2022 after it was aborted after few seconds on 20 June 2022.[60][61]
19	NG-18 Sally Ride		Northrop Grumman CRS Flight 18	Enhanced	7 November 2022, 10:32:42	Antares 230+	8,173 lb (3,707 kg)	Success	[62][63][64]
			6 November 2022 launch attempt scrubbed due to fire alarm in mission control.[65]
20	NG-19 Laurel Clark		Northrop Grumman CRS Flight 19	Enhanced	2 August 2023, 00:31:14	Antares 230+	8,345 lb (3,785 kg)	Success	[66][63]
21	NG-20 Patricia “Patty” Hilliard Robertson		Northrop Grumman CRS Flight 20	Enhanced	30 January 2024, 17:07:15	Falcon 9 Block 5 ♺ (B1077.10)	8,345 lb (3,785 kg)	Success	[67]
			Northrop Grumman contracted with SpaceX to launch this Cygnus on a Falcon 9 Block 5 rocket from Cape Canaveral Space Force Station.
22	NG-21		Northrop Grumman CRS Flight 21	Enhanced	August 2024	Falcon 9 Block 5	TBA	TBA	[68]
23	NG-22		Northrop Grumman CRS Flight 22	Enhanced	February 2025	Falcon 9 Block 5	TBA	TBA	[69]
24	NG-23		Northrop Grumman CRS Flight 23	Mission B	June 2025	Antares 330	TBA	TBA	[70][3]
			Scheduled to be the first flight of the Antares 330 and the larger Mission B Cygnus.
25	NG-24		Northrop Grumman CRS Flight 24	Mission B	January 2026[71]	Antares 330	TBA	TBA
25	NG-25		Northrop Grumman CRS Flight 25	Mission B	2026[72]	Antares 330	TBA	TBA

See also

• Space Shuttle retirement
• Comparison of space station cargo vehicles

References

External links

• Cygnus spacecraft – Northrop Grumman
• Orbital Sciences news page for Cygnus (archived)
• Thales Alenia Space page for Cygnus (archived)
• Computer animation of the Standard Cygnus delivering cargo to the ISS – YouTube