Cygnus (spacecraft)




The Cygnus spacecraft is an expendable American cargo spacecraft developed by Orbital Sciences Corporation and now manufactured and launched by Northrop Grumman Innovation Systems as part of NASA's Commercial Resupply Services program. It is launched by Northrop Grumman's Antares rocket or ULA's Atlas V and is designed to transport supplies to the International Space Station following the retirement of the American Space Shuttle. Since August 2000, ISS resupply missions have been regularly flown by the Russian Progress spacecraft, as well as by the European Automated Transfer Vehicle, and the Japanese H-II Transfer Vehicle. With the Cygnus spacecraft and the SpaceX Dragon, NASA seeks to increase its partnerships with domestic commercial aviation and aeronautics industry.
Cygnus is the Latinized Greek word for swan and a northern constellation.

Development

With Rocketplane Kistler unable to meet funding obligations for its K-1 launch vehicle under the terms of the COTS agreement, NASA decided on 18 October 2007 to terminate its contract with Rocketplane Kistler and re-award its contract after a competition. On 19 February 2008, the NASA announced that it had chosen Orbital Sciences as the new winner. On 23 December 2008, NASA awarded Orbital Sciences a $1.9 billion contract under the Commercial Resupply Services program. Under this contract, Orbital Sciences will deliver up to 20 tons of cargo to the ISS through 2016 in eight Cygnus spacecraft flights.
By April 2010, Orbital had displayed a full-scale model of the Cygnus cargo delivery spacecraft at the National Space Symposium in Colorado Springs, CO.
Launched on an Antares medium-class launch vehicle or Atlas V, the first Cygnus flight was originally planned to occur in December 2010.· The Cygnus demonstration mission was successfully launched on 18 September 2013. 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.·
With the December 2015 launch of Orb CRS-4 on Atlas V, the Enhanced version 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. On the other hand, the lessons learned on packing and the extra capabilities of the Atlas allowed payload to be increased to.

Design

The Cygnus spacecraft consists of two basic components: the Pressurized Cargo Module and the Service Module. The PCM is manufactured by Thales Alenia Space in Turin,. The initial PCMs have an empty mass of 1,500 kg and a volume of 18 m3·. The service module is built by Orbital ATK and is based on their GEOStar and LEOStar spacecraft buses as well as components from the development of the Dawn spacecraft. It has a gross mass of 1,800 kg with propulsion provided by thrusters using the hypergolic propellants hydrazine and nitrogen tetroxide and is capable of producing up to 4 kW of electrical power via two gallium arsenide solar arrays. On 12 November 2009, Dutch Space announced it will provide the solar arrays for the initial Cygnus spacecraft.
The fourth and all subsequent Cygnus spacecraft are planned to be of the "Enhanced" variant, as the standard variant has been retired. These will use a stretched 1,800-kilogram PCM which increases the interior volume to 27 m3 and the service module will use Orbital ATK Ultraflex solar arrays which will provide the same amount of power as the previous solar arrays but at a lower mass.· A new upper stage built by Orbital ATK, the Castor 30XL, will be used in conjunction with the enhanced Cygnus; because of the more powerful upper stage and the lighter solar arrays, the payload that Cygnus can deliver to the ISS will be increased by 700 kg.
During nominal 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 in a similar fashion to the Japanese H-II Transfer Vehicle and the other American CRS vehicle, the SpaceX Dragon. For typical missions, Cygnus is planned to remain berthed for about 30 days.· Cygnus does not provide return capability, but can be loaded with obsolete equipment and trash for destructive reentry similar to the Russian Progress vehicles.
A formerly planned variant of Cygnus would have replaced the PCM with the Unpressurized Cargo Module, based on NASA's ExPRESS Logistics Carrier, and would have been used to transport unpressurized cargo, such as ISS Orbital Replacement Units.· Another proposed variant would have replaced the PCM with the Return Cargo Module, which would have allowed Cygnus to return cargo to Earth.·

CRS-2 Versions

On 10 April 2014, NASA announced to potential bidders new requirements for the delivery and disposal of pressurized and unpressurized cargo to and from the International Space Station.
To meet NASA's requirements for the CRS-2 contract, Orbital ATK put together a bid that included three different variants of its Cygnus spacecraft to meet the various requirements outlined in the CRS-2 contract. Orbital was awarded a CRS-2 logistics contract on 14 January 2016.
The first version would be the Enhanced Cygnus upgraded to carry 10% to 15% more pressurized cargo than the current CRS-1 Cygnus version.
The second version would be a larger Pressurized Cargo Module that would use an Atlas V rocket. This would deliver the largest pressurized cargo volume to ISS.
The third version would be an Unpressurized Cargo Module, based on NASA's ExPRESS Logistics Carrier. The unpressurized Cygnus would look different than its pressurized counterparts, with a cargo carrier taking the place of the PCM. The unpressurized Cygnus would berth to the Common Berthing Mechanism, just like the current cargo vehicles to US Operating Segment.
In essence, what Orbital ATK proposed for their CRS-2 contract was an Antares-based Cygnus design and an Atlas-based Cygnus to take advantage of both vehicle lifting capabilities – placing the smaller Cygnus on Antares and the larger Cygnus with more cargo on an Atlas V.

Lunar Gateway module variant

In August 2019, NASA decided to sole source its design for the Minimal Habitation Module of the Gateway to Northrop Grumman Innovation Systems, which offered a minimalist design based directly on the Enhanced Cygnus as well as a larger 7-meter by 4.4-meter design also based on the Cygnus. The module would be launched and placed in lunar orbit in early 2024, and would host the crew of Artemis 3 and the commercial lunar lander by the end of the year. The weight constraints would likely require launch aboard an Atlas V, Delta IV Heavy, or Vulcan rocket.

Missions

List includes only currently manifested missions. Eight missions are currently planned to be launched from Mid-Atlantic Regional Spaceport Launch Pad 0A on Antares, while two are planned to be launched on Atlas V rocket from Cape Canaveral SLC-41.
The PCM of each mission thus far has been named after a deceased NASA person.