Elliptic orbitIn astrodynamics or celestial mechanics, an elliptic orbit or elliptical orbit is a Kepler orbit with an eccentricity of less than 1; this includes the special case of a circular orbit, with eccentricity equal to 0. In a stricter sense, it is a Kepler orbit with the eccentricity greater than 0 and less than 1 (thus excluding the circular orbit). In a wider sense, it is a Kepler orbit with negative energy. This includes the radial elliptic orbit, with eccentricity equal to 1.
Uncrewed spacecraftRobotic spacecraft or uncrewed spacecraft are spacecraft without people on board. Uncrewed spacecraft may have varying levels of autonomy from human input; they may be remote controlled, remote guided or autonomous: they have a pre-programmed list of operations, which they will execute unless otherwise instructed. A robotic spacecraft for scientific measurements is often called a space probe or space observatory. Many space missions are more suited to telerobotic rather than crewed operation, due to lower cost and risk factors.
Hohmann transfer orbitIn astronautics, the Hohmann transfer orbit (ˈhoʊmən) is an orbital maneuver used to transfer a spacecraft between two orbits of different altitudes around a central body. Examples would be used for travel between low Earth orbit and the Moon, or another solar planet or asteroid. In the idealized case, the initial and target orbits are both circular and coplanar. The maneuver is accomplished by placing the craft into an elliptical transfer orbit that is tangential to both the initial and target orbits.
Spacecraft designThe design of spacecraft covers a broad area, including the design of both robotic spacecraft (satellites and planetary probes), and spacecraft for human spaceflight (spaceships and space stations). Spacecraft design was born as a discipline in the 1950s and 60s with the advent of American and Soviet space exploration programs. Since then it has progressed, although typically less than comparable terrestrial technologies. This is for a large part due to the challenging space environment, but also to the lack of basic R&D, and to other cultural factors within the design community.
Orion (spacecraft)Orion (officially 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 and the European Service Module (ESM) manufactured by Airbus Defence and Space. Capable of supporting a crew of six 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 modeled after those used in the Boeing 787 Dreamliner.
Space Shuttle ChallengerSpace Shuttle Challenger (OV-099) was a Space Shuttle orbiter manufactured by Rockwell International and operated by NASA. Named after the commanding ship of a nineteenth-century scientific expedition that traveled the world, Challenger was the second Space Shuttle orbiter to fly into space after Columbia, and launched on its maiden flight in April 1983. It was destroyed in January 1986 soon after launch in an accident that killed all seven crewmembers aboard.
Orbital mechanicsOrbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. The motion of these objects is usually calculated from Newton's laws of motion and the law of universal gravitation. Orbital mechanics is a core discipline within space-mission design and control. Celestial mechanics treats more broadly the orbital dynamics of systems under the influence of gravity, including both spacecraft and natural astronomical bodies such as star systems, planets, moons, and comets.
Docking and berthing of spacecraftDocking and berthing of spacecraft is the joining of two space vehicles. This connection can be temporary, or partially permanent such as for space station modules. Docking specifically refers to joining of two separate free-flying space vehicles. Berthing refers to mating operations where a passive module/vehicle is placed into the mating interface of another space vehicle by using a robotic arm. Because the modern process of un-berthing requires more crew labor and is time-consuming, berthing operations are unsuited for rapid crew evacuations in the event of an emergency.
Low Earth orbitA low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never more than about one-third of the radius of Earth. The term LEO region is also used for the area of space below an altitude of (about one-third of Earth's radius). Objects in orbits that pass through this zone, even if they have an apogee further out or are sub-orbital, are carefully tracked since they present a collision risk to the many LEO satellites.
Shenzhou (spacecraft)Shenzhou (, 'ʃɛn'dʒoʊ; see ) is a spacecraft developed and operated by China to support its crewed spaceflight program, China Manned Space Program. Its design resembles the Russian Soyuz spacecraft, but it is larger in size. The first launch was on 19 November 1999 and the first crewed launch was on 15 October 2003. In March 2005, an asteroid was named 8256 Shenzhou in honour of the spacecraft. The literal meaning of the native name 神舟 (p: Shénzhōu; 'ʃɛn'dʒoʊ) is "the Divine vessel [on the Heavenly River]", to which Heavenly River (天河) means the Milky Way in Classical Chinese.
