A trans-lunar injection (TLI) is a propulsive maneuver, which is used to send a spacecraft to the Moon. Typical lunar transfer trajectories approximate Hohmann transfers, although low-energy transfers have also been used in some cases, as with the Hiten probe. For short duration missions without significant perturbations from sources outside the Earth-Moon system, a fast Hohmann transfer is typically more practical.
A geostationary transfer orbit (GTO) or geosynchronous transfer orbit is a type of geocentric orbit. Satellites that are destined for geosynchronous (GSO) or geostationary orbit (GEO) are (almost) always put into a GTO as an intermediate step for reaching their final orbit.
The Interplanetary Transport Network (ITN) is a collection of gravitationally determined pathways through the Solar System that require very little energy for an object to follow. The ITN makes particular use of Lagrange points as locations where trajectories through space can be redirected using little or no energy. These points have the peculiar property of allowing objects to orbit around them, despite lacking an object to orbit. While it would use little energy, transport along the network would take a long time.
Nozomi was a Japanese Mars orbiter that failed to reach Mars due to electrical failure. It was constructed by the Institute of Space and Astronautical Science, University of Tokyo and launched on July 4, 1998, at 03:12 JST with an on-orbit dry mass of 258 kg and 282 kg of propellant. The Nozomi mission was terminated on December 31, 2003.
A geocentric orbit, Earth-centered orbit, or Earth orbit involves any object orbiting Earth, such as the Moon or artificial satellites. In 1997, NASA estimated there were approximately 2,465 artificial satellite payloads orbiting Earth and 6,216 pieces of space debris as tracked by the Goddard Space Flight Center. More than 16,291 objects previously launched have undergone orbital decay and entered Earth's atmosphere.
In spaceflight, an orbital maneuver is the use of propulsion systems to change the orbit of a spacecraft. For spacecraft far from Earth an orbital maneuver is called a deep-space maneuver (DSM).
The Hiten spacecraft, given the English name Celestial Maiden and known before launch as MUSES-A, part of the MUSES Program, was built by the Institute of Space and Astronautical Science of Japan and launched on January 24, 1990. It was Japan's first lunar probe, the first robotic lunar probe since the Soviet Union's Luna 24 in 1976, and the first lunar probe launched by a country other than the Soviet Union or the United States. The spacecraft was named after flying heavenly beings in Buddhism.
A supersynchronous orbit is either an orbit with a period greater than that of a synchronous orbit, or just an orbit whose major axis is larger than that of a synchronous orbit. A synchronous orbit has a period equal to the rotational period of the body which contains the barycenter of the orbit.
In astronomy and spaceflight, a lunar orbit is an orbit of an object around Earth's Moon. In general these orbits are not circular. When farthest from the Moon a spacecraft is said to be at apolune, apocynthion, or aposelene. When closest to the Moon it is said to be at perilune, pericynthion, or periselene. These derive from names or epithets of the moon goddess.
A low-energy transfer, or low-energy trajectory, is a route in space that allows spacecraft to change orbits using significantly less fuel than traditional transfers. These routes work in the Earth–Moon system and also in other systems, such as between the moons of Jupiter. The drawback of such trajectories is that they take longer to complete than higher-energy (more-fuel) transfers, such as Hohmann transfer orbits.
AsiaSat 3S, was a geosynchronous communications satellite for AsiaSat of Hong Kong to provide communications and television services all across Asia, the Middle East and Oceania.
Paksat-1,, was a geosynchronous and communications satellite built and owned by the Boeing Company, leased to the Space & Upper Atmosphere Research Commission (SUPARCO) and renamed Paksat-1. It was successfully put on orbit on 1 February 1996 as Palapa-C1 for Indonesia as its original customer. But, after the technical problems, the satellite was leased to SUPARCO at an orbital location of 38° East longitude in December 2002. Paksat-1 offers the C-band and Ku-band coverage in over 75 countries across Europe, Africa, Middle East, South and Central Asia. Its customers included government organizations, television broadcasters, telecommunications companies, data and broadband internet service providers.
AMC-14 is a communications satellite. Initially owned by SES Americom, AMC-14 was designed to be placed in geostationary orbit, following launch on a Proton-M / Briz-M space vehicle. Built by Lockheed Martin and based on the A2100 satellite bus, AMC-14 was to have been located at 61.5° West longitude for Dish Network service.
Orion 3 was an American spacecraft which was intended for use by Orion Network Systems, as a geostationary communications satellite. It was to have been positioned in geostationary orbit at a longitude of 139° East, from where it was to have provided communications services to Asia and Oceania. Due to a malfunction during launch, it was instead delivered to a useless low Earth orbit.
Artemis 2 is a scheduled mission of the NASA-led Artemis program. It will use the second launch of the Space Launch System (SLS) and include the first crewed mission of the Orion spacecraft. The mission is scheduled for no earlier than September 2025. Four astronauts will perform a flyby of the Moon and return to Earth, becoming the first crew to travel beyond low Earth orbit since Apollo 17 in 1972. Artemis 2 will be the first crewed launch from Launch Complex 39B of the Kennedy Space Center since STS-116 in 2006.
Ballistic capture is a low energy method for a spacecraft to achieve an orbit around a distant planet or moon with no fuel required to go into orbit. In the ideal case, the transfer is ballistic after launch. In the traditional alternative to ballistic capture, spacecraft would either use a Hohmann transfer orbit or Oberth effect, which requires the spacecraft to burn fuel in order to slow down at the target. A requirement for the spacecraft to carry fuel adds to its cost and complexity.
Manfred Memorial Moon Mission (4M) was the first private lunar probe to successfully fly by the Moon. It was led by LuxSpace, a child company of German OHB System, and named in honor of OHB Systems founder, Manfred Fuchs, who died in 2014. It was launched with the Chinese Chang'e 5-T1 test spacecraft on 23 October 2014. The lunar flyby took place on 28 October 2014, after which the spacecraft entered elliptical Earth orbit and continued transmission until 11 November 2014, exceeding its designed lifetime by four times.
ArgoMoon is a CubeSat that was launched into a heliocentric orbit on Artemis 1, the maiden flight of the Space Launch System, on 16 November 2022 at 06:47:44 UTC. The objective of the ArgoMoon spacecraft is to take detailed images of the Interim Cryogenic Propulsion Stage following Orion separation, an operation that will demonstrate the ability of a cubesat to conduct precise proximity maneuvers in deep space. ASI has not confirmed nor denied whether this took place, but several images of the Earth and the Moon were taken.
EQUULEUS is a nanosatellite of the 6U CubeSat format that will measure the distribution of plasma that surrounds the Earth (plasmasphere) to help scientists understand the radiation environment in that region. It will also demonstrate low-thrust trajectory control techniques, such as multiple lunar flybys, within the Earth-Moon region using water steam as propellant. The spacecraft was designed and developed jointly by the Japan Aerospace Exploration Agency (JAXA) and the University of Tokyo.
