Spacecraft
Spacecraft
The US Space Shuttle flew 135 times from 1981 to 2011, supporting Spacelab, Mir, the Hubble Space Telescope, and the ISS. (Columbia's first launch, which had a white external tank, shown)
A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle (carrier rocket).
On a sub-orbital spaceflight, a space vehicle enters space and then returns to the surface, without having gained sufficient energy or velocity to make a full orbit of the Earth. For orbital spaceflights, spacecraft enter closed orbits around the Earth or around other celestial bodies. Spacecraft used for human spaceflight carry people on board as crew or passengers from start or on orbit (space stations) only, whereas those used for robotic space missions operate either autonomously or telerobotically. Robotic spacecraft used to support scientific research are space probes. Robotic spacecraft that remain in orbit around a planetary body are artificial satellites. To date, only a handful of interstellar probes, such as Pioneer 10 and 11, Voyager 1 and 2, and New Horizons, are on trajectories that leave the Solar System.
Orbital spacecraft may be recoverable or not. Most are not. Recoverable spacecraft may be subdivided by method of reentry to Earth into non-winged space capsules and winged spaceplanes.
Humanity has achieved space flight but only a few nations have the technology for orbital launches: Russia (RSA or "Roscosmos"), the United States (NASA), the member states of the European Space Agency (ESA), Japan (JAXA), China (CNSA), India (ISRO), Taiwan[1][2][3][4][5][6] (National Chung-Shan Institute of Science and Technology, Taiwan National Space Organization (NSPO),[7][8][9] Israel (ISA), Iran (ISA), and North Korea (NADA).
History
The first artificial satellite, Sputnik 1. It was launched by the Soviet Union
A German V-2 became the first spacecraft when it reached an altitude of 189 km in June 1944 in Peenemünde, Germany.[10] Sputnik 1 was the first artificial satellite. It was launched into an elliptical low Earth orbit (LEO) by the Soviet Union on 4 October 1957. The launch ushered in new political, military, technological, and scientific developments; while the Sputnik launch was a single event, it marked the start of the Space Age.[11][12] Apart from its value as a technological first, Sputnik 1 also helped to identify the upper atmospheric layer's density, through measuring the satellite's orbital changes. It also provided data on radio-signal distribution in the ionosphere. Pressurized nitrogen in the satellite's false body provided the first opportunity for meteoroid detection. Sputnik 1 was launched during the International Geophysical Year from Site No.1/5, at the 5th Tyuratam range, in Kazakh SSR (now at the Baikonur Cosmodrome). The satellite travelled at 29,000 kilometers (18,000 mi) per hour, taking 96.2 minutes to complete an orbit, and emitted radio signals at 20.005 and 40.002 MHz
While Sputnik 1 was the first spacecraft to orbit the Earth, other man-made objects had previously reached an altitude of 100 km, which is the height required by the international organization Fédération Aéronautique Internationale to count as a spaceflight. This altitude is called the Kármán line. In particular, in the 1940s there were several test launches of the V-2 rocket, some of which reached altitudes well over 100 km.
Spacecraft types
Crewed spacecraft
Apollo 17 Command Module in Lunar orbit
As of 2016, only three nations have flown crewed spacecraft: USSR/Russia, USA, and China. The first crewed spacecraft was Vostok 1, which carried Soviet cosmonaut Yuri Gagarin into space in 1961, and completed a full Earth orbit. There were five other crewed missions which used a Vostok spacecraft.[13] The second crewed spacecraft was named Freedom 7, and it performed a sub-orbital spaceflight in 1961 carrying American astronaut Alan Shepard to an altitude of just over 187 kilometers (116 mi). There were five other crewed missions using Mercury spacecraft.
Other Soviet crewed spacecraft include the Voskhod, Soyuz, flown uncrewed as Zond/L1, L3, TKS, and the Salyut and Mir crewed space stations. Other American crewed spacecraft include the Gemini spacecraft, Apollo spacecraft including the Apollo Lunar Module, the Skylab space station, and the Space Shuttle with undetached European Spacelab and private US Spacehab space stations-modules. China developed, but did not fly Shuguang, and is currently using Shenzhou (its first crewed mission was in 2003).
Except for the Space Shuttle, all of the recoverable crewed orbital spacecraft were space capsules.
The International Space Station, crewed since November 2000, is a joint venture between Russia, the United States, Canada and several other countries.
Spaceplanes
Columbia orbiter landing
Some reusable vehicles have been designed only for crewed spaceflight, and these are often called spaceplanes. The first example of such was the North American X-15 spaceplane, which conducted two crewed flights which reached an altitude of over 100 km in the 1960s. The first reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19, 1963.
The first partially reusable orbital spacecraft, a winged non-capsule, the Space Shuttle, was launched by the USA on the 20th anniversary of Yuri Gagarin's flight, on April 12, 1981. During the Shuttle era, six orbiters were built, all of which have flown in the atmosphere and five of which have flown in space. Enterprise was used only for approach and landing tests, launching from the back of a Boeing 747 SCA and gliding to deadstick landings at Edwards AFB, California. The first Space Shuttle to fly into space was Columbia, followed by Challenger, Discovery, Atlantis, and Endeavour. Endeavour was built to replace Challenger when it was lost in January 1986. Columbia broke up during reentry in February 2003.
The first automatic partially reusable spacecraft was the Buran-class shuttle, launched by the USSR on November 15, 1988, although it made only one flight and this was uncrewed. This spaceplane was designed for a crew and strongly resembled the U.S. Space Shuttle, although its drop-off boosters used liquid propellants and its main engines were located at the base of what would be the external tank in the American Shuttle. Lack of funding, complicated by the dissolution of the USSR, prevented any further flights of Buran. The Space Shuttle was subsequently modified to allow for autonomous re-entry in case of necessity.
Per the Vision for Space Exploration, the Space Shuttle was retired in 2011 due mainly to its old age and high cost of program reaching over a billion dollars per flight. The Shuttle's human transport role is to be replaced by SpaceX's Dragon V2 and Boeing's CST-100 Starliner no later than 2017. The Shuttle's heavy cargo transport role is to be replaced by expendable rockets such as the Space Launch System and SpaceX's Falcon Heavy.
Scaled Composites' SpaceShipOne was a reusable suborbital spaceplane that carried pilots Mike Melvill and Brian Binnie on consecutive flights in 2004 to win the Ansari X Prize. The Spaceship Company will build its successor SpaceShipTwo. A fleet of SpaceShipTwos operated by Virgin Galactic was planned to begin reusable private spaceflight carrying paying passengers in 2014, but was delayed after the crash of VSS Enterprise.
Unmanned spacecraft
Designed as manned but flown as unmanned only spacecraft
Zond/L1 – lunar flyby capsule
L3 – capsule and lunar lander
TKS – capsule
Buran-class shuttle – Soviet shuttle
Semi-manned – manned as space stations or part of space stations
Progress – unmanned USSR/Russia cargo spacecraft
TKS – unmanned USSR/Russia cargo spacecraft and space station module
Automated Transfer Vehicle (ATV) – unmanned European cargo spacecraft
H-II Transfer Vehicle (HTV) – unmanned Japanese cargo spacecraft
SpaceX Dragon – unmanned private spacecraft
Tianzhou 1 – China's unmanned spacecraft
Earth-orbit satellites
Explorer 1 – first US satellite
Project SCORE – first communications satellite
Solar and Heliospheric Observatory (SOHO) - orbits the Sun near L1
Sputnik 1 – world's first artificial satellite
Sputnik 2 – first animal in orbit (Laika)
Korabl-Sputnik 2 – first capsule recovered from orbit (Vostok precursor) – animals survived
Syncom – first geosynchronous communications satellite
Hubble Space Telescope – largest orbital observatory
X-37 – spaceplane
Lunar probes
Artist's conception of Cassini–Huygens as it enters Saturn's orbit
Artist's conception of the Phoenix spacecraft as it lands on Mars
Clementine – US Navy mission, orbited Moon, detected hydrogen at the poles
Kaguya JPN – lunar orbiter
Luna 1 – first lunar flyby
Luna 2 – first lunar impact
Luna 3 – first images of lunar far side
Luna 9 – first soft landing on the Moon
Luna 10 – first lunar orbiter
Luna 16 – first unmanned lunar sample retrieval
Lunar Orbiter – very successful series of lunar mapping spacecraft
Lunar Prospector – confirmed detection of hydrogen at the lunar poles
Lunar Reconnaissance Orbiter – Identifies safe landing sites and locates Moon resources
Lunokhod - Soviet lunar rovers
SMART-1 ESA – Lunar Impact
Surveyor – USA's first soft lander
Chang'e 1 – China's Chang'e lunar mission
Chang'e 2 – China's Chang'e lunar mission
Chang'e 3 – China's Chang'e lunar mission
Chandrayaan 1 – first Indian Lunar mission
Chandrayaan 2 – second Indian Lunar mission
Planetary probes
Akatsuki JPN – a Venus orbiter
Cassini–Huygens – first Saturn orbiter and Titan lander
Curiosity – Rover sent to Mars by NASA in 2012
Galileo – first Jupiter orbiter and descent probe
IKAROS JPN – first solar-sail spacecraft
Mariner 4 – first Mars flyby, first close and high resolution images of Mars
Mariner 9 – first Mars orbiter
Mariner 10 – first Mercury flyby, first close up images
Mars Exploration Rovers (Spirit and Opportunity)– Mars rovers
Mars Express – Mars orbiter
Mars Global Surveyor – Mars orbiter
Mars Orbiter Mission (Mangalyaan) - India's first Interplanetary probe
Mars Reconnaissance Orbiter – an advanced climate, imaging, sub-surface radar, and telecommunications Mars orbiter
MESSENGER – first Mercury orbiter (arrival 2011)
Mars Pathfinder – Mars lander, carrying the Sojourner rover
New Horizons – first Pluto flyby (arrival 2015)
Pioneer 10 – first Jupiter flyby, first close up images
Pioneer 11 – second Jupiter flyby and first Saturn flyby (first close up images of Saturn)
Pioneer Venus – first Venus orbiter and landers
Vega 1 – Balloon release into Venus atmosphere and lander (joint mission with Vega 2), mothership continued on to fly by Halley's Comet
Venera 4 – first soft landing on another planet (Venus)
Viking 1 – first soft landing on Mars
Voyager 1 - flybys of Jupiter, Saturn, and Saturn's moon Titan
Voyager 2 – Jupiter flyby, Saturn flyby, and first flybys/images of Neptune and Uranus
Other – deep space
Cluster
Deep Space 1
Deep Impact
Genesis
Hayabusa
Near Earth Asteroid Rendezvous
Stardust
STEREO – Heliospheric and solar sensing; first images of the entire Sun
WMAP
Fastest spacecraft
Parker Solar Probe (estimated 343,000 km/h or 213,000 mph at first sun close pass, will reach 700,000 km/h or 430,000 mph at final perihelion)[14]
Helios I and II Solar Probes (252,792 km/h or 157,078 mph)
Furthest spacecraft from the Sun
Unfunded and canceled programs
Manned spacecraft
Chinese Shuguang capsule
Soviet Soyuz Kontakt capsule
Soviet Almaz space station
US Manned Orbiting Laboratory space station
US Altair lunar lander
Multi-stage spaceplanes
US X-20 spaceplane
Soviet Spiral shuttle
Soviet/Russian Buran-class shuttle
ESA Hermes shuttle
Kliper Russian semi-shuttle/semi-capsule
Japanese HOPE-X shuttle
Chinese Shuguang Project 921-3 shuttle
SSTO spacecraft
RR/British Aerospace HOTOL
ESA Hopper Orbiter
US DC-X (Delta Clipper)
US Roton Rotored-Hybrid
US VentureStar
Spacecraft under development
Crewed
(US-NASA) Orion Multi-Purpose Crew Vehicle – capsule
(US-SpaceX) Dragon V2 – capsule
(US-Boeing) CST-100 – capsule
(US-Sierra Nevada Corporation) Dream Chaser – orbital spaceplane
(US-The SpaceShip company) SpaceShipTwo suborbital spaceplane
(US-Blue Origin) New Shepard – VTVL capsule
(US-XCOR) Lynx rocketplane – suborbital spaceplane
China Shenzhou spacecraft
(India-DRDO) Avatar RLV -Under development, First demonstration flight planned in 2015.[16]
(India-ISRO) Gaganyaan – capsule
(India-ISRO) RLV Technology Demonstration Programme - Spacecraft
SpaceX Starship
(Russia-RKA) Orel – capsule
(Europe-ESA) Advanced Crew Transportation System – capsule
(Iranian Space Agency) Orbital Vehicle – capsule
Uncrewed
ESA and JAXA BepiColombo - Planetary Probe to Mercury
China Shenzhou (spacecraft) Cargo
CNES Mars Netlander
Orbital Sciences Cygnus – cargo delivery to the ISS
Darwin14 ESA probe
James Webb Space Telescope (delayed)
Mars 2020 rover
Reaction Engines Limited
Skylon
SpaceX Dragon – cargo delivery to the ISS
StarChip and Sprites - miniaturized interstellar spacecraft
System F6—a DARPA Fractionated Spacecraft demonstrator
Terrestrial Planet Finder cancelled probe
Subsystems
Reaction control system thrusters on the front of the U.S. Space Shuttle
A spacecraft system comprises various subsystems, depending on the mission profile. Spacecraft subsystems comprise the spacecraft's "bus" and may include attitude determination and control (variously called ADAC, ADC, or ACS), guidance, navigation and control (GNC or GN&C), communications (comms), command and data handling (CDH or C&DH), power (EPS), thermal control (TCS), propulsion, and structures. Attached to the bus are typically payloads.
- Life supportSpacecraft intended for human spaceflight must also include alife support systemfor the crew.
- Attitude controlA Spacecraft needs anattitude controlsubsystem to be correctly oriented in space and respond to externaltorquesand forces properly. The attitude control subsystem consists ofsensorsandactuators, together with controlling algorithms. The attitude-control subsystem permits proper pointing for the science objective, sun pointing for power to the solar arrays and earth pointing for communications.
- GNCGuidance refers to the calculation of the commands (usually done by the CDH subsystem) needed to steer the spacecraft where it is desired to be. Navigation means determining a spacecraft'sorbital elementsor position. Control means adjusting the path of the spacecraft to meet mission requirements.
- Command and data handlingThe CDH subsystem receives commands from the communications subsystem, performs validation and decoding of the commands, and distributes the commands to the appropriate spacecraft subsystems and components. The CDH also receives housekeeping data and science data from the other spacecraft subsystems and components, and packages the data for storage on adata recorderor transmission to the ground via the communications subsystem. Other functions of the CDH include maintaining the spacecraft clock and state-of-health monitoring.
- CommunicationsSpacecraft, bothroboticandcrewed, utilize various communications systems for communication with terrestrial stations as well as for communication between spacecraft in space. Technologies utilized includeRFandopticalcommunication. In addition, some spacecraft payloads are explicitly for the purpose of ground–groundcommunicationusingreceiver/retransmitterelectronic technologies.
- PowerSpacecraft need an electrical power generation and distribution subsystem for powering the various spacecraft subsystems. For spacecraft near theSun,solar panelsare frequently used to generate electrical power. Spacecraft designed to operate in more distant locations, for exampleJupiter, might employ aradioisotope thermoelectric generator(RTG) to generate electrical power. Electrical power is sent through power conditioning equipment before it passes through a power distribution unit over an electrical bus to other spacecraft components. Batteries are typically connected to the bus via a battery charge regulator, and the batteries are used to provide electrical power during periods when primary power is not available, for example when a low Earth orbit spacecraft iseclipsedby Earth.
- Thermal controlSpacecraft must be engineered to withstand transit throughEarth's atmosphereand thespace environment. They must operate in avacuumwith temperatures potentially ranging across hundreds of degreesCelsiusas well as (if subject to reentry) in the presence of plasmas. Material requirements are such that either high melting temperature, low density materials such asberylliumandreinforced carbon–carbonor (possibly due to the lower thickness requirements despite its high density)tungstenorablativecarbon–carbon composites are used. Depending on mission profile, spacecraft may also need to operate on the surface of another planetary body. Thethermal control subsystemcan be passive, dependent on the selection of materials with specific radiative properties. Active thermal control makes use of electrical heaters and certainactuatorssuch as louvers to control temperature ranges of equipments within specific ranges.
- Spacecraft propulsionSpacecraft may or may not have apropulsionsubsystem, depending on whether or not the mission profile calls for propulsion. TheSwiftspacecraft is an example of a spacecraft that does not have a propulsion subsystem. Typically though, LEO spacecraft include a propulsion subsystem for altitude adjustments (drag make-up maneuvers) andinclinationadjustment maneuvers. A propulsion system is also needed for spacecraft that perform momentum management maneuvers. Components of a conventional propulsion subsystem include fuel, tankage, valves, pipes, andthrusters. The thermal control system interfaces with the propulsion subsystem by monitoring the temperature of those components, and by preheating tanks and thrusters in preparation for a spacecraft maneuver.
- StructuresSpacecraft must be engineered to withstand launch loads imparted by the launch vehicle, and must have a point of attachment for all the other subsystems. Depending on mission profile, the structural subsystem might need to withstand loads imparted by entry into theatmosphere of another planetary body, and landing on the surface of another planetary body.
- PayloadThe payload depends on the mission of the spacecraft, and is typically regarded as the part of the spacecraft "that pays the bills". Typical payloads could include scientific instruments (cameras,telescopes, orparticle detectors, for example), cargo, or ahuman crew.
- Ground segment
- Theground segment, though not technically part of the spacecraft, is vital to the operation of the spacecraft. Typical components of a ground segment in use during normal operations include a mission operations facility where the flight operations team conducts the operations of the spacecraft, a data processing and storage facility,ground stationsto radiate signals to and receive signals from the spacecraft, and a voice and data communications network to connect all mission elements.[17]
- Launch vehicleThelaunch vehiclepropels the spacecraft from Earth's surface, through theatmosphere, and into anorbit, the exact orbit being dependent on the mission configuration. The launch vehicle may beexpendableorreusable.