Space capsule in the context of "Mercury-Redstone 3"

Vostok 1 (Russian: Восток, lit. 'East' or 'Orient') was the first spaceflight of the Vostok programme and the first human orbital spaceflight in history. The Vostok 3KA space capsule was launched from Baikonur Cosmodrome on 12 April 1961, with Soviet cosmonaut Yuri Gagarin aboard, making him the first human to reach orbital velocity around the Earth and to complete a full orbit around the Earth.

The orbital spaceflight consisted of a single orbit around Earth which skimmed the upper atmosphere at 169 kilometers (105 miles; 91 nautical miles) at its lowest point. The flight took 108 minutes from launch to landing. Gagarin parachuted to the ground separately from his capsule after ejecting at 7 km (23,000 ft) altitude.

Orion (Orion Multi-Purpose Crew Vehicle or Orion MPCV) is a partially reusable crewed spacecraft used in NASA's Artemis program. The spacecraft consists of a Crew Module (CM) space capsule designed by Lockheed Martin that is paired with a European Service Module (ESM) manufactured by Airbus Defence and Space. Capable of supporting a crew of four beyond low Earth orbit, Orion can last up to 21 days undocked and up to six months docked. It is equipped with solar panels, an automated docking system, and glass cockpit interfaces. Orion is launched atop a Space Launch System (SLS) rocket, with a tower launch escape system.

Orion was conceived in the early 2000s by Lockheed Martin as a proposal for the Crew Exploration Vehicle (CEV) to be used in NASA's Constellation program and was selected by NASA in 2006. Following the cancellation of the Constellation program in 2010, Orion was extensively redesigned for use in NASA's Journey to Mars initiative; later named Moon to Mars. The SLS became Orion's primary launch vehicle, and the service module was replaced with a design based on the European Space Agency's Automated Transfer Vehicle. A development version of Orion's crew module was launched in 2014 during Exploration Flight Test-1, while at least four test articles were produced. Orion was primarily designed by Lockheed Martin Space Systems in Littleton, Colorado, with former Space Shuttle engineer Julie Kramer White at NASA as Orion's chief engineer.

A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from substances that are already present in the battery. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.

The first fuel cells were invented by Sir William Grove in 1838. The first commercial use of fuel cells came almost a century later following the invention of the hydrogen–oxygen fuel cell by Francis Thomas Bacon in 1932. The alkaline fuel cell, also known as the Bacon fuel cell after its inventor, has been used in NASA space programs since the mid-1960s to generate power for satellites and space capsules. Since then, fuel cells have been used in many other applications. Fuel cells are used for primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. They are also used to power fuel cell vehicles, including forklifts, automobiles, buses, trains, boats, motorcycles, and submarines.

Soyuz 11 (Russian: Союз 11, lit. 'Union 11') was the only crewed mission to board the world's first space station, Salyut 1. The crew, Georgy Dobrovolsky, Vladislav Volkov, and Viktor Patsayev, arrived at the space station on 7 June 1971, and departed on 29 June 1971. The mission ended in disaster when the crew capsule depressurised during preparations for re-entry, killing the three-person crew. The three crew members of Soyuz 11 are the only humans to have died in space.

Reusable spacecraft are spacecraft capable of repeated launch, atmospheric reentry, and landing or splashdown. This contrasts with expendable spacecraft which are designed to be discarded after use. Agencies operating reusable spacecraft aim to have lower costs and higher flight frequencies.

Reusable spacecraft may be crewed or uncrewed and orbital or sub-orbital. Examples include spaceplanes such as the Space Shuttle and the Boeing X-37B, and space capsules such as the SpaceX Dragon. The Blue Origin New Shepard is an example of a sub-orbital spacecraft.

A launch escape system (LES) or launch abort system (LAS) is a crew-safety system connected to a space capsule. It is used in the event of a critical emergency to quickly separate the capsule from its launch vehicle in case of an emergency requiring the abort of the launch, such as an impending explosion. The LES is typically controlled by a combination of automatic rocket failure detection, and a manual activation for the crew commander's use. The LES may be used while the launch vehicle is on the launch pad, or during its ascent. Such systems are usually of three types:

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  A solid-fueled rocket, mounted above the capsule on a tower, which delivers a relatively large thrust for a brief period of time to send the capsule a safe distance away from the launch vehicle, at which point the capsule's parachute recovery system can be used for a safe landing on ground or water. The escape tower and rocket are jettisoned from the space vehicle in a normal flight at the point where it is either no longer needed, or cannot be effectively used to abort the flight. These have been used on the Mercury, Apollo, Soyuz, and Shenzhou capsules.
• The crew are seated in seats that eject themselves (ejection seats) as used in military aircraft; each crew member returns to Earth with an individual parachute. Such systems are effective only in a limited range of altitudes and speeds. These have been used on the Vostok and Gemini capsules, and Space Shuttle Columbia during its testing phase.
• Thrusters integrated in the capsule or its detachable service module having the same function as an escape tower, as in the case of Crew Dragon, Starliner and New Shepard.

Dragon 2 is a class of partially reusable spacecraft developed, manufactured, and operated by the American space company SpaceX for flights to the International Space Station (ISS) and private spaceflight missions. The spacecraft, which consists of a reusable space capsule and an expendable trunk module, has two variants: the 4-person Crew Dragon and Cargo Dragon, a replacement for the Dragon 1 cargo capsule. The spacecraft launches atop a Falcon 9 Block 5 rocket, and the capsule returns to Earth through splashdown.

Crew Dragon's primary role is to transport crews to and from the ISS under NASA's Commercial Crew Program, a task handled by the Space Shuttle until it was retired in 2011. It will be joined by Boeing's Starliner in this role when NASA certifies it. Crew Dragon is also used for commercial flights to ISS and other destinations and is expected to be used to transport people to and from Axiom Space's planned space station.

The Space Transportation System (STS), also known internally to NASA as the Integrated Program Plan (IPP), was a proposed system of reusable crewed space vehicles envisioned in 1969 to support extended operations beyond the Apollo program (NASA appropriated the name for its Space Shuttle Program, the only component of the proposal to survive Congressional funding approval). The purpose of the system was two-fold: to reduce the cost of spaceflight by replacing the existing method of launching capsules on expendable rockets with reusable spacecraft; and to support ambitious follow-on programs including permanent orbiting space stations around Earth and the Moon, and a human landing mission to Mars.

In February 1969, President Richard Nixon appointed a Space Task Group headed by Vice President Spiro Agnew to recommend human space projects beyond Apollo. The group responded in September with the outline of the STS, and three different program levels of effort culminating with a human Mars landing by 1983 at the earliest, and by the end of the twentieth century at the latest. The system's major components consisted of: