Spacecraft
[1] Spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo.
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.
Recoverable spacecraft may be subdivided by a method of reentry to Earth into non-winged space capsules and winged spaceplanes.
Recoverable spacecraft may be reusable (can be launched again or several times, like the SpaceX Dragon and the Space Shuttle orbiters) or expendable (like the Soyuz).
Humanity has achieved space flight, but only a few nations have the technology for orbital launches: Russia (Roscosmos[2]), the United States (NASA[3]), the member states of the European Space Agency,[4] Japan (JAXA[5]), China (CNSA[6]), India (ISRO[7]), Taiwan (TSA[8][9][10]), Israel (ISA), Iran (ISA), and North Korea (NADA).
[12][13] Apart from its value as a technological first, Sputnik 1 also helped to identify the upper atmospheric layer's density, by measuring the satellite's orbital changes.
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 kilometres per hour (18,000 mph), 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 human-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.
The first crewed spacecraft was Vostok 1, which carried Soviet cosmonaut Yuri Gagarin into space in 1961, and completed a full Earth orbit.
[14] 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).
US company Boeing also developed and flown a spacecraft of their own, the CST-100, commonly referred to as Starliner, but a crewed flight is yet to occur.
The International Space Station, crewed since November 2000, is a joint venture between Russia, the United States, Canada and several other countries.
Outer planets such as Saturn, Uranus, and Neptune are too distant to reach with current crewed spaceflight technology, so telerobotic probes are the only way to explore them.
Telerobotics also allows exploration of regions that are vulnerable to contamination by Earth micro-organisms since spacecraft can be sterilized.
For example, the Buran spaceplane could operate autonomously but also had manual controls, though it never flew with crew onboard.
The high frequency radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth.
As of 2023, three different cargo spacecraft are used to supply the International Space Station: Russian Progress, American SpaceX Dragon 2 and Cygnus.
Being robotic eliminates the need for expensive, heavy life support systems (the Apollo crewed Moon landings required the use of the Saturn V rocket that cost over a billion dollars per launch, adjusted for inflation) and so allows for lighter, less expensive rockets.
The identical Voyager probes, weighing 721.9 kilograms (1,592 lb),[28] were launched in 1977 to take advantage of a rare alignment of Jupiter, Saturn, Uranus and Neptune that would allow a spacecraft to visit all four planets in one mission, and get to each destination faster by using gravity assist.
A lander is a type of spacecraft that makes a soft landing on the surface of an astronomical body other than Earth.
This involves the spacecraft using a fuel burn to change its trajectory so it will pass through a planet (or a moon's) atmosphere.
Drag caused by the spacecraft hitting the atmosphere enables it to slow down without using fuel, however this generates very high temperatures and so adds a requirement for a heat shield of some sort.
The first example of such was the North American X-15 spaceplane, which conducted two crewed flights which reached an altitude of over 100 kilometres (62 mi) in the 1960s.
The first autonomous reusable spaceplane was the Buran-class shuttle, launched by the USSR on November 15, 1988, although it made only one flight and this was uncrewed.
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.
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.
It consisted of two reusable Solid Rocket Boosters that landed by parachute, were recovered at sea, and were the most powerful rocket motors ever made until they were superseded by those of NASA’s SLS rocket, with a liftoff thrust of 2,800,000 pounds-force (12 MN), which soon increased to 3,300,000 pounds-force (15 MN) per booster,[31] and were fueled by a combination of PBAN and APCP, the Space Shuttle Orbiter, with 3 RS-25 engines that used a liquid oxygen/liquid hydrogen propellant combination, and the bright orange throwaway Space Shuttle external tank from which the RS-25 engines sourced their fuel.
Though the shuttle’s goals were to drastically decrease launch costs, it did not do so, ending up being much more expensive than similar expendable launchers.
The spacecraft is designed to transport both crew and cargo to a variety of destinations, including Earth orbit, the Moon, Mars, and potentially beyond.
Furthermore, the spacecraft will be used to refuel other Starship vehicles to allow them to reach higher orbits to and other space destinations.
