Last updated Structural test article for the Service Module, delivered to NASA in November 2015
The Orion Service Module is the service module component of the Orion spacecraft, serving as its primary power and propulsion component until it is discarded at the end of each mission. In January 2013, NASA announced that the European Space Agency (ESA) will contribute the service module for Exploration Mission 1, replacing the previous design. Based on ESA's Automated Transfer Vehicle (ATV), the new design is also known as the European Service Module (ESM).
A service module is a spacecraft compartment containing a variety of support systems used for spacecraft operations. Usually located in the uninhabited area of the spacecraft, the service module is jettisoned upon the completion of the mission, and usually burns up during atmospheric reentry. The service module is the equivalent to the spacecraft bus assembly on unmanned spacecraft.
The Orion Multi-Purpose Crew Vehicle is an American-European interplanetary spacecraft intended to carry a crew of four astronauts to destinations at or beyond low Earth orbit (LEO). Currently under development by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) for launch on the Space Launch System, Orion is intended to facilitate human exploration of the Moon, asteroids and of Mars and to retrieve crew or supplies from the International Space Station if needed.
The National Aeronautics and Space Administration is an independent agency of the United States Federal Government responsible for the civilian space program, as well as aeronautics and aerospace research.
The service module supports the crew module from launch through separation prior to reentry. It provides in-space propulsion capability for orbital transfer, attitude control, and high altitude ascent aborts. It provides the water and oxygen needed for a habitable environment, generates and stores electrical power, and maintains the temperature of the vehicle's systems and components. This module can also transport unpressurized cargo and scientific payloads.
History
Old design
Pre-ATV Service Module designArtist's conception of the Orion Spacecraft in lunar orbit with circular solar panels
Roughly cylindrical in shape, the original American-designed Orion service module, would, like the crew module, have been constructed of Al-Li alloy (to keep weight down), and would have featured a pair of deployable circular solar panels, similar in design to the panels used on the Mars Phoenix lander. The panels, the first to be used on a U.S. manned spacecraft (except for a 10-year period, the Soviet/Russian Soyuz spacecraft has used them since the first mission in 1967), would allow NASA to eliminate the need to carry malfunction-prone fuel cells, and their associated hardware (mainly LH2 tanks) in the service module, resulting in a shorter, yet more maneuverable spacecraft. Successful initial testing of an Orion solar array design using full-scale "UltraFlex wing" hardware was reported in October, 2008.[1]
Photovoltaic solar panels absorb sunlight as a source of energy to generate electricity. A photovoltaic (PV) module is a packaged, connected assembly of typically 6x10 photovoltaic solar cells. Photovoltaic modules constitute the photovoltaic array of a photovoltaic system that generates and supplies solar electricity in commercial and residential applications.
Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.
The Orion Main Engine (OME) was a 7500-pound thrust, pressure-fed, regeneratively cooled, storable bi-propellant rocket engine to be made by Aerojet. The OME was an increased performance version of the 6000-pound thrust rocket engine used by the Space Shuttle for its Orbital Maneuvering System (OMS). The SM Reaction Control System (RCS), the spacecraft's maneuvering thrusters (originally based on the Apollo "quad" system, but resembling that used on Gemini), would also be pressure-fed, and would use the same propellants. NASA believed the SM RCS would be able to act as a backup for a trans-Earth injection (TEI) burn in case the main SM engine fails.
A trans-Earth injection (TEI) is a propulsion maneuver used to set a spacecraft on a trajectory which will intersect the Earth's Sphere of influence, usually putting the spacecraft on a Free return trajectory.
A pair of LOX tanks (similar to those used in the Apollo SM) would provide, along with small tanks of nitrogen, the crew with breathing air at sea-level or "cruising altitude" pressure (14.7 or 10.2 psi), with a small "surge tank" providing necessary life support during reentry and touchdown. Lithium hydroxide (LiOH) cartridges would recycle the spacecraft's environmental system by "scrubbing" the carbon dioxide (CO2) exhaled by the astronauts from ship's air and adding fresh oxygen and nitrogen, which was then cycled back out into the system loop. Because of the switch from fuel cells to solar panels, the service module would have an onboard water tank to provide drinking water for the crew, and (when mixed with glycol), cooling water for the spacecraft's electronics. Unlike the practice during Apollo of dumping both water and urine overboard during the flight, the Orion would have an onboard recycling system, identical to that used on the International Space Station, to convert both waste water and urine into both drinking and cooling water.
Lithium hydroxide is an inorganic compound with the formula LiOH. It is a white hygroscopic crystalline material. It is soluble in water and slightly soluble in ethanol, and is available commercially in anhydrous form and as the monohydrate (LiOH.H2O), both of which are strong bases. It is the weakest base among the alkali metal hydroxides.
The International Space Station (ISS) is a space station, or a habitable artificial satellite, in low Earth orbit. Its first component was launched into orbit in 1998, with the first long-term residents arriving in November 2000. It has been inhabited continuously since that date. The last pressurised module was fitted in 2011, and an experimental inflatable space habitat was added in 2016. The station is expected to operate until 2030. Development and assembly of the station continues, with several new elements scheduled for launch in 2019. The ISS is the largest human-made body in low Earth orbit and can often be seen with the naked eye from Earth. The ISS consists of pressurised habitation modules, structural trusses, solar arrays, radiators, docking ports, experiment bays and robotic arms. ISS components have been launched by Russian Proton and Soyuz rockets and American Space Shuttles.
The Service Module also mounted the spacecraft's waste heat management system (its radiators) and the aforementioned solar panels. These panels, along with backup batteries located in the Orion CM, would provide in-flight power to the ship's systems. The voltage, 28 voltsDC, was similar to that used on the Apollo spacecraft during flight.
The volt is the derived unit for electric potential, electric potential difference (voltage), and electromotive force. It is named after the Italian physicist Alessandro Volta (1745–1827).
Direct current (DC) is the unidirectional flow of electric charge. A battery is a good example of a DC power supply. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A term formerly used for this type of current was galvanic current.
The Orion service module would be encapsulated by fiberglass shrouds jettisoned at the same time as the LES/Boost Protective Cover, which would take place roughly 2½ minutes after launch (30 seconds after the solid rocket first stage was jettisoned). Prior to the "Orion 606" redesign, the Orion SM resembled a squat, enlarged version of the Apollo Service Module. The "Orion 606" SM design retained the 5-meter width for the attachments of the Orion SM with the Orion CM, but utilized a Soyuz-like service module design to allow Lockheed Martin to make the vehicle lighter in weight and permitting the attachment of the circular solar panels at the module's midpoints, instead of at the base near the spacecraft/rocket adapter, which might have subjected the panels to damage.
The Orion service module (SM) was projected comprising a cylindrical shape, having a diameter of 5.03 m (16ft 6 in) and an overall length (including thruster) of 4.78 m (15ft 8 in). With solar panels extended, span was either 17.00m (55.77ft) or 55.00ft (16.76 m)[clarification needed]. The projected empty mass was 3,700kg (8,000lb), fuel capacity was 8,300kg (18,000lb).[2][3]
A review of the Constellation programme in 2009 by the Augustine Commission prompted by the new Obama Administration had found that five years in it was already running four years behind its 2020 lunar target and was woefully underfunded, the only element worth continuing was the Crew Exploration Vehicle in the role of a space station escape capsule. This led in 2010 to the Administration cancelling the programme by withdrawing funding in the proposed 2011 budget. A public outcry led to the programme being frozen rather than outright cancelled and a review launched in to how costs could be cut which found that it was possible to continue if there was an emphasis on finding alternate funding, reducing the complexity by narrowing the scope to focus on the Moon and deep space rather than Mars and through reusing existing hardware reducing the range of equipment requiring development. The Ares 1 launcher intended for crew flights which had significant design issues being overweight, prone to dangerous vibration and in the case of a catastrophic failure its blast radius exceeded the escape systems ejection range was cancelled and the capacity of the Ares 5 was reduced by a third and renamed the Space Launch System serving both previous roles, the three different Crew Exploration Vehicle designs were merged in to a single Multipurpose Crew Exploration Vehicle.
In May 2011 the European Space Agency (ESA) Director General announced a possible collaboration with NASA to work on a successor to ESA's Automated Transfer Vehicle (ATV).[4] ESA's provision of this successor could be counted towards its 8% share of the operating costs of the International Space Station (ISS); the ATV missions resupplying the station only covered this obligation up to 2017. On 21 June 2012, Astrium announced that it had been awarded two separate studies to evaluate possible future missions building on the technology and experience gained from its development of ATV and the Columbus laboratory. The first study looked into the construction of a service module which would be used in tandem with the Orion capsule.[5] The second examined the production of a versatile multi-purpose orbital vehicle. Each study was worth €6.5 million.[6]
In November 2012, ESA obtained the commitment of its member states for it to construct an ATV-derived service module for Orion, to fly on the maiden flight of the Space Launch System, thereby meeting ESA's budgetary obligation to NASA regarding the ISS for 2017–20.[7] No decision was made about supplying the module for later Orion flights.[8]
Orion spacecraft including the ATV-derived Service Module
In January 2013, NASA announced its agreement, made the preceding December, that ESA would build the service module for Exploration Mission 1, then scheduled to take place in 2017. This service module was not required for Exploration Flight Test 1 in 2014, as this used a test service module supplied by Lockheed Martin.[9] On 17 November 2014 ESA signed a €390 million fixed price contract with Airbus Defence and Space for the development and construction of the first ATV-based service module.[10] In December 2016, ESA's member states agreed it would extend its commitment to the ISS to 2024, and would supply a second service module, as part of the resulting budgetary obligation.[11]
The new design, sometimes referred to as the European Service Module (ESM),[12] is c. 16.5 feet (5.0m) in diameter and c. 13 feet (4.0m) in length, and made of aluminium-lithium alloy.[13]
The new design for the solar arrays, replacing ATK's circular UltraFlex design,[14] is by Airbus Defence and Space,[13] whose subsidiary, Airbus Defence and Space Netherlands (then known as Dutch Space), built the ATV's X-shaped array of four panels. The ATV's array generated 4.6 kilowatts. The upgraded version for the service module will generate about 11 kilowatts,[14] and will span about 62ft (19m) when extended.[13]
In September 2015, Thales Alenia Space signed a contract with Airbus Defence and Space to develop and produce thermomechanical systems for the service module, including structure and micrometeoroid protection, thermal control and consumable storage and distribution.[15]
Service Module shown with the Crew Module, adapters and fairing panels
Lockheed Martin is building the two adapters, connecting the service module to the crew module and to the upper stage of the Space Launch System, and also the three fairing panels that are jettisoned after protecting the service module during launch and ascent.[13]
On 16 February 2017 a €200m contract was signed between Airbus and the European Space Agency for the production of a second European Service Module for use on the first manned Orion flight.[16]
The service module's main engine for Exploration Mission 1 will be a Space Shuttle Orbital Maneuvering System (OMS) AJ10-190 engine left over from the Space Shuttle program,[12] in which it flew on 19 missions and carried out 89 burns.[13] It is intended that the OMS will be used for the first three Service Modules and four alternate engine designs are under consideration for later flights, thought to include the AJ10-118k; used for the second stage of the Delta II it is a lighter and more powerful version in the same AJ10 engine family whose lineage began with the Vanguard.[17]
In comparison with the Apollo Command Service Module which previously took man to the Moon, the Orion Service Module generates approx. twice as much electricity (11.2kW vs 6.3kW), weighs nearly 40% less fuelled (15,461kg vs 24,520kg) and is 12% smaller (208.66 m2vs 238 m2 volume) supporting the environment for a slightly larger habitable volume on the crew module (8.95 m3 vs 6.17 m3) though it will have just over a third less delta v (1800m/s vs 2800m/s).
The Orion service module will be able to support a crew of four for 21 days against the 14 day endurance for the three man Apollo.
Specifications
Dimensions
4 m long
diameter of 4.1 m excluding solar panels, 5.2 m diameter stowed 19 m with wings unfurled
Primary engine
1 Space Shuttle Orbital Maneuvering System providing 26.6kN
Secondary engine
8 490 N Aerojet R-4D-11 Auxiliary Thrusters providing 3.92kN
Maneuvering thrusters
24 220 N Airbus Reaction Control System Engines in six pods of four
Fuel capacity
9,000kg in four 2000 l propellant tanks, 2 mixed oxides of nitrogen (MON) and 2 monomethyl hydrazine (MMH)
Power generation
11.2kW from 4 x 7.375 m wings each containing 3 solar panels
Consumables
240kg of water in four tanks, 90kg of oxygen in three tanks, 30kg of nitrogen in one tank
The Apollo Lunar Module, or simply lunar module, originally designated the lunar excursion module (LEM), was the spacecraft which was flown to and landed on the Moon. The lander spacecraft were built for the US Apollo program by Grumman Aircraft. The lunar module, consisting of a descent stage and an ascent stage, was ferried from the Earth to the Moon attached to the Apollo spacecraft command and service module (CSM), approximately twice its mass. The ascent stage carried a crew of two who flew the spacecraft from lunar orbit to the surface and later back to the command module. Designed for lunar orbit rendezvous, the Apollo Lunar Module was discarded after completing its mission. It was capable of operation only in outer space; structurally and aerodynamically it was incapable of flight through the Earth's atmosphere. The lunar module was the first manned spacecraft to operate exclusively in the airless vacuum of space. It was the first, and to date only, crewed vehicle to land anywhere beyond Earth.
The Progress is a Russian expendable cargo spacecraft. Its purpose is to deliver supplies needed to sustain human presence in orbit. While it does not carry a crew it can be boarded by astronauts when docked with a space station, hence it being classified as manned by its manufacturer. Progress is derived from the manned Soyuz spacecraft and launches on the same vehicle, a Soyuz rocket.
The Automated Transfer Vehicle, originally Ariane Transfer Vehicle or ATV, was an expendable cargo spacecraft developed by the European Space Agency (ESA) 1995–2007, used for space cargo transport in 2008–2014. The ATV design was launched to orbit five times, exclusively by the Ariane 5 heavy-lift launch vehicle. It functioned much like the Russian Progress cargo spacecraft for carrying upmass to a single destination—the International Space Station (ISS)—but with three times the capacity.
The Constellation Program is a cancelled manned spaceflight program developed by NASA, the space agency of the United States, from 2005 to 2009. The major goals of the program were "completion of the International Space Station" and a "return to the Moon no later than 2020" with a crewed flight to the planet Mars as the ultimate goal. The program's logo reflected the three stages of the program: the Earth (ISS), the Moon, and finally Mars—while the Mars goal also found expression in the name given to the program's booster rockets: Ares. The technological aims of the program included the regaining of significant astronaut experience beyond low Earth orbit and the development of technologies necessary to enable sustained human presence on other planetary bodies.
The Apollo spacecraft was composed of three parts designed to accomplish the American Apollo program's goal of landing astronauts on the Moon by the end of the 1960s and returning them safely to Earth. The expendable (single-use) spacecraft consisted of a combined command and service module (CSM) and a lunar module (LM). Two additional components complemented the spacecraft stack for space vehicle assembly: a spacecraft–LM adapter (SLA) designed to shield the LM from the aerodynamic stress of launch and to connect the CSM to the Saturn launch vehicle; and a launch escape system (LES) to carry the crew in the command module safely away from the launch vehicle in the event of a launch emergency.
The Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother ship, which carried a crew of three astronauts and the second Apollo spacecraft, the lunar module, to lunar orbit, and brought the astronauts back to Earth. It consisted of two parts: the conical command module, a cabin that housed the crew and carried equipment needed for atmospheric reentry and splashdown; and the cylindrical service module which provided propulsion, electrical power and storage for various consumables required during a mission. An umbilical connection transferred power and consumables between the two modules. Just before reentry of the command module on the return home, the umbilical connection was severed and the service module was cast off and allowed to burn up in the atmosphere.
Shuttle-Derived Launch Vehicle, or simply Shuttle-Derived Vehicle (SDV), is a term describing one of a wide array of concepts that have been developed for creating space launch vehicles from the components, technology and infrastructure of the Space Shuttle program. SDVs have also been part of NASA's plans several times in the past. In the late 1980s and early 1990s, NASA formally studied a cargo-only vehicle, Shuttle-C, that would have supplemented the crewed Space Shuttle in orbiting payloads.
The Exploration Systems Architecture Study (ESAS) is the official title of a large-scale, system level study released by the National Aeronautics and Space Administration (NASA) in November 2005 in response to American president George W. Bush's announcement on January 14, 2004 of his goal of returning astronauts to the Moon and eventually Mars — known as the Vision for Space Exploration.
CSTS or ACTS is a human spaceflight system proposal. It was originally a joint project between the European Space Agency (ESA) and the Russian Space Agency (FKA), but is now solely an ESA project. It aims to design a spacecraft for low Earth orbit operations such as servicing the International Space Station but also capable of exploration of the Moon and beyond. This study was conceived as a basic strategic plan to keep a viable European human space program alive because NASA officials had announced that NASA's Vision for Space Exploration Orion spacecraft, subsequently cancelled, would be developed without participation of international partners.
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars. Ares I was originally known as the "Crew Launch Vehicle" (CLV).
A number of proposals for a crewed Venus flyby have been considered since the start of the space age.
The Crew Exploration Vehicle (CEV) was the conceptual component of the U.S. NASA Vision for Space Exploration that later became known as the Orion spacecraft. The Orion CEV was part of NASA's Constellation Program to send human explorers back to the Moon, and then onward to Mars and other destinations in the solar system.
NASA's Orion multi-purpose crew vehicle (MPCV) was planned as the first American spacecraft since Project Apollo to use an escape system in the event of a launch abort, something its predecessor, the Space Shuttle, had for only its first four orbital test flights in 1981–1982. Like the Apollo command and service module (CSM), the Orion CEV would use the launch escape system (LES), a solid-fueled tractor rocket that would be able to pull the Orion crew module away from a malfunctioning Space Launch System (SLS) rocket during the initial launch phase. Based on the launch escape system found on the Soviet/Russian Soyuz spacecraft, the LAS, designed and manufactured by ATK for the Orion CEV, would be larger than the Soyuz version and will have more thrust than the Atlas 109-D booster that carried astronaut John Glenn into orbit in 1962.
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