Cygnus is an
expendable
''Expendable'' is a science fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imagination, imaginative and futuristic concepts such as advanced science and technolog ...
American
cargo spacecraft
Cargo spacecraft are robotic spacecraft that are designed to carry cargo, possibly to support space stations' operation by transporting food, propellant and other supplies. This is different from a space probe, whose missions are to conduct scien ...
developed by
Orbital Sciences Corporation
Orbital Sciences Corporation (commonly referred to as Orbital) was an American company specializing in the design, manufacture, and launch of small- and medium- class space and launch vehicle systems for commercial, military and other governmen ...
and now manufactured and launched by
Northrop Grumman Space Systems as part of
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeedi ...
's
Commercial Resupply Services
Commercial Resupply Services (CRS) are a series of flights awarded by NASA for the delivery of cargo and supplies to the International Space Station (ISS) on commercially operated spacecraft. The first CRS contracts were signed in 2008 and awarde ...
(CRS) program. It is launched by Northrop Grumman's
Antares rocket or
ULA's
Atlas V
Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Marti ...
and is designed to transport supplies to the
International Space Station
The International Space Station (ISS) is the largest Modular design, modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos ( ...
(ISS) following the retirement of the American
Space Shuttle
The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program na ...
. Since August 2000,
ISS resupply missions have been regularly flown by the
Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eigh ...
n
Progress
Progress is the movement towards a refined, improved, or otherwise desired state. In the context of progressivism, it refers to the proposition that advancements in technology, science, and social organization have resulted, and by extension w ...
spacecraft, as well as by the
European Automated Transfer Vehicle
The Automated Transfer Vehicle, originally Ariane Transfer Vehicle or ATV, was an expendable automated cargo spacecraft, cargo spacecraft developed by the European Space Agency (ESA), used for space cargo transport in 2008–2015. The ATV desi ...
, and the
Japanese
Japanese may refer to:
* Something from or related to Japan, an island country in East Asia
* Japanese language, spoken mainly in Japan
* Japanese people, the ethnic group that identifies with Japan through ancestry or culture
** Japanese diaspor ...
H-II Transfer Vehicle. With the Cygnus spacecraft and the
SpaceX Dragon
American private space transportation company SpaceX has developed and produced several spacecraft named Dragon. The first family member, now referred to as Dragon 1, flew 23 cargo missions to the ISS between 2010 and 2020 before being retired. ...
, NASA seeks to increase its partnerships with domestic commercial aviation and aeronautics industry.
''Cygnus'' is the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...
ized
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
word for
swan
Swans are birds of the family Anatidae within the genus ''Cygnus''. The swans' closest relatives include the geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometim ...
and a northern
constellation.
Development

With
Rocketplane Kistler
Rocketplane Kistler (RpK) was a reusable launch system firm originally based in Oklahoma. It was formed in 2006 after Rocketplane Limited, Inc. acquired Kistler Aerospace. NASA announced that Rocketplane Kistler had been chosen to develop crew an ...
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, 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
Commercial Resupply Services (CRS) are a series of flights awarded by NASA for the delivery of cargo and supplies to the International Space Station (ISS) on commercially operated spacecraft. The first CRS contracts were signed in 2008 and awarde ...
(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.
By April 2010, Orbital had displayed a full-scale model of the Cygnus cargo delivery spacecraft at the
National Space Symposium (NSS) in Colorado Springs, CO.
Launched on an
Antares
Antares is the brightest star in the constellation of Scorpius. It has the Bayer designation α Scorpii, which is Latinised to Alpha Scorpii. Often referred to as "the heart of the scorpion", Antares is flanked by σ Scorpii and τ S ...
(renamed from
Taurus II) medium-class launch vehicle or
Atlas V
Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Marti ...
, 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
Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Marti ...
, 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 .
Design

The Cygnus spacecraft consists of two basic components: the Pressurized Cargo Module (PCM) and the Service Module (SM). The PCM is manufactured by
Thales Alenia Space
Thales Alenia Space () is a Franco-Italian aerospace manufacturer. A joint venture between the French technology corporation Thales Group (67%) and Italian defense conglomerate Leonardo (33%), the company is the largest satellite manufactur ...
in
Turin
Turin ( , Piedmontese: ; it, Torino ) is a city and an important business and cultural centre in Northern Italy. It is the capital city of Piedmont and of the Metropolitan City of Turin, and was the first Italian capital from 1861 to 1865. Th ...
, (
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...
). The initial PCMs have an empty mass of 1,500 kg
and a volume of 18 m
3·.
The service module is built by
Orbital ATK and is based on their
GEOStar
''Geostari'' ( Georgian: ჯეოსტარი) is the Georgian franchise of the Idol series, which airs on Rustavi 2. Georgia is the fifth former Soviet country to have acquired an ''Idol'' franchise after Armenia, Estonia, Kazakhstan, ...
and
LEOStar
Star Bus is a satellite bus family of Orbital ATK. It was originally developed by Thomas van der Heyden, co-founder of CTAI, and later sold to and manufactured by Orbital Sciences Corporation.
History
The first satellite program based on the ...
spacecraft bus
A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held.
Bus-derived satellites are opposed to specially produced satellites. Bus-d ...
es as well as components from the development of the
Dawn spacecraft
''Dawn'' is a retired space probe that was launched by NASA in September 2007 with the mission of studying two of the three known protoplanets of the asteroid belt: Vesta and Ceres. In the fulfillment of that mission—the ninth in NASA's Dis ...
. It has a gross mass of 1,800 kg with propulsion provided by thrusters using the
hypergolic
A hypergolic propellant is a rocket propellant combination used in a rocket engine, whose components spontaneously ignite when they come into contact with each other.
The two propellant components usually consist of a fuel and an oxidizer. The ...
propellants
hydrazine
Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazin ...
and
nitrogen tetroxide
Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russia rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium ...
(the propellant mass is 800 kg
). The service module is capable of producing up to 4 kW of electrical power via two
gallium arsenide solar arrays.
On 12 November 2009,
Dutch Space
Dutch commonly refers to:
* Something of, from, or related to the Netherlands
* Dutch people ()
* Dutch language ()
Dutch may also refer to:
Places
* Dutch, West Virginia, a community in the United States
* Pennsylvania Dutch Country
People E ...
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 (empty weight) PCM which increases the interior volume to 27 m
3 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
The Mobile Servicing System (MSS), is a robotic system on board the International Space Station (ISS). Launched to the ISS in 2001, it plays a key role in station assembly and maintenance; it moves equipment and supplies around the station, su ...
robotic arm
grapples the spacecraft and
berths it to a
Common Berthing Mechanism
The Common Mechanism (CBM) connects habitable elements in the US Orbital Segment (USOS) of the International Space Station (ISS). The CBM has two distinct sides that, once mated, form a cylindrical vestibule between modules. The vestibule is ...
on the
Harmony module in a similar fashion to the Japanese
H-II Transfer Vehicle and the retired
SpaceX Dragon
American private space transportation company SpaceX has developed and produced several spacecraft named Dragon. The first family member, now referred to as Dragon 1, flew 23 cargo missions to the ISS between 2010 and 2020 before being retired. ...
,
but not the other active American CRS
Dragon 2 vehicle, which docks autonomously. For typical missions, Cygnus is planned to remain berthed for about 30 days.
·
Unlike Dragon 2 and the earlier Dragon, Cygnus does not provide cargo return capability. However, it 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 (UCM), based on NASA's
ExPRESS Logistics Carrier
An EXpedite the PRocessing of Experiments to Space Station (ExPRESS) Logistics Carrier (ELC) is an unpressurized attached payload platform for the International Space Station (ISS) that provides mechanical mounting surfaces, electrical power, and ...
, 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 (RCM), which would have allowed Cygnus to return cargo to Earth.
·
Lunar Gateway module variant
In August 2019, NASA decided to sole source its design for the Minimal Habitation Module (now known as the Habitation and Logistics Outpost, or HALO) of the
Lunar Gateway
The Lunar Gateway, or simply Gateway, is the first planned extraterrestrial space station in lunar orbit intended to serve as a solar-powered communication hub, science laboratory, and short-term habitation module for government-agency ast ...
to Northrop Grumman Innovation Systems, which offered a minimalist 6.1-meter (20 feet) by 3-meter (9.8 feet) design based directly on the Enhanced Cygnus, as well as a larger 7-meter (22.9 feet) by 4.4-meter (14.4 feet) design also based on the Cygnus,
to the outside of which radial docking ports, body-mounted radiators (BMRs), batteries and communications antennae will be added. 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.
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.
Missions
''List includes only missions that have flown and five planned missions. one mission is currently planned to be launched from
Mid-Atlantic Regional Spaceport Launch Pad 0A on the one remaining
Antares
Antares is the brightest star in the constellation of Scorpius. It has the Bayer designation α Scorpii, which is Latinised to Alpha Scorpii. Often referred to as "the heart of the scorpion", Antares is flanked by σ Scorpii and τ S ...
230+ rocket, three are to be launched on the
Falcon 9
Falcon 9 is a partially reusable medium lift launch vehicle that can carry cargo and crew into Earth orbit, produced by American aerospace company SpaceX.
The rocket has two stages. The first (booster) stage carries the second stage and pa ...
rocket from
Cape Canaveral SLC-40, and one from Wallops on an
Antares 330
Development
The NASA COTS award was for and Orbital Sciences expected to invest an additional $150 million, split between $130 million for the booster and $20 million for the spacecraft. A Commercial Resupply Service contract of $1.9 bil ...
''.
The PCM of each mission thus far has been named after a deceased NASA staffer (mostly
astronaut
An astronaut (from the Ancient Greek (), meaning 'star', and (), meaning 'sailor') is a person trained, equipped, and deployed by a human spaceflight program to serve as a commander or crew member aboard a spacecraft. Although generally r ...
s).
In March 2022, NASA ordered six additional flights, Cygnus NG-20 to NG-25, to resupply the ISS through 2026.
See also
*
Space Shuttle retirement
The retirement of NASA's Space Shuttle fleet took place from March to July 2011. ''Discovery'' was the first of the three active Space Shuttles to be retired, completing its final mission on March 9, 2011; '' Endeavour'' did so on June 1. The ...
*
Comparison of space station cargo vehicles
Comparison or comparing is the act of evaluating two or more things by determining the relevant, comparable characteristics of each thing, and then determining which characteristics of each are similar to the other, which are different, and t ...
References
External links
Orbital Sciences news page for CygnusNASA Commercial Resupply Mission Update : Northrop GrummanThales Alenia Space page for CygnusComputer animation of the Standard Cygnus delivering cargo to the ISS - Youtube
{{Use American English, date=January 2014
Cargo spacecraft
American spacecraft
Supply vehicles for the International Space Station
Vehicles introduced in 2013
Northrop Grumman spacecraft
Orbital Sciences Corporation
Commercial spaceflight