Galileo was an American robotic space program that studied the planet Jupiter and its moons, as well as several other Solar System bodies. Named after the Italian astronomer Galileo Galilei, the Galileo spacecraft consisted of an orbiter and an atmospheric entry probe. It was delivered into Earth orbit on October 18, 1989, by Space ShuttleAtlantis on the STS-34 mission, and arrived at Jupiter on December 7, 1995, after gravity assist flybys of Venus and Earth, and became the first spacecraft to orbit Jupiter. The spacecraft then launched the first probe to directly measure its atmosphere. Despite suffering major antenna problems, Galileo achieved the first asteroid flyby, of 951 Gaspra, and discovered the first asteroid moon, Dactyl, around 243 Ida. In 1994, Galileo observed Comet Shoemaker–Levy 9's collision with Jupiter.
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry.
Solar sails are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large surfaces. A number of spaceflight missions to test solar propulsion and navigation have been proposed since the 1980s. The first spacecraft to make use of the technology was IKAROS, launched in 2010.
In spacecraft propulsion, a Hall-effect thruster (HET) is a type of ion thruster in which the propellant is accelerated by an electric field. Hall-effect thrusters are sometimes referred to as Hall thrusters or Hall-current thrusters. Hall-effect thrusters use a magnetic field to limit the electrons' axial motion and then use them to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume. The Hall-effect thruster is classed as a moderate specific impulse space propulsion technology and has benefited from considerable theoretical and experimental research since the 1960s.
An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft propulsion. An ion thruster creates a cloud of positive ions from a neutral gas by ionizing it to extract some electrons from its atoms. The ions are then accelerated using electricity to create thrust. Ion thrusters are categorized as either electrostatic or electromagnetic.
Spaceflight is an application of astronautics to fly objects, usually spacecraft, into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in orbit around Earth, but also includes space probes for flights beyond Earth orbit. Such spaceflights operate either by telerobotic or autonomous control. The first spaceflights began in the 1950s with the launches of the Soviet Sputnik satellites and American Explorer and Vanguard missions. Human spaceflight programs include the Soyuz, Shenzhou, the past Apollo Moon landing and the Space Shuttle programs. Other current spaceflight are conducted to the International Space Station and to China's Tiangong Space Station.
Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the varying conditions within the Solar System and its heliosphere. This includes the effects of the solar wind, especially on the Earth's magnetosphere, ionosphere, thermosphere, and exosphere. Though physically distinct, space weather is analogous to the terrestrial weather of Earth's atmosphere. The term "space weather" was first used in the 1950s and popularized in the 1990s. Later, it prompted research into "space climate", the large-scale and long-term patterns of space weather.
The Gravity Recovery and Climate Experiment (GRACE) was a joint mission of NASA and the German Aerospace Center (DLR). Twin satellites took detailed measurements of Earth's gravity field anomalies from its launch in March 2002 to the end of its science mission in October 2017. The two satellites were sometimes called Tom and Jerry, a nod to the famous cartoon. The GRACE Follow-On (GRACE-FO) is a continuation of the mission on near-identical hardware, launched in May 2018. On March 19, 2024, NASA announced that the successor to GRACE-FO would be Gravity Recovery and Climate Experiment-Continuity (GRACE-C), to be launched in or after 2028.
Juno is a NASA space probe orbiting the planet Jupiter. It was built by Lockheed Martin and is operated by NASA's Jet Propulsion Laboratory. The spacecraft was launched from Cape Canaveral Air Force Station on August 5, 2011 UTC, as part of the New Frontiers program. Juno entered a polar orbit of Jupiter on July 5, 2016, UTC, to begin a scientific investigation of the planet. After completing its mission, Juno was originally planned to be intentionally deorbited into Jupiter's atmosphere, but has since been approved to continue orbiting until contact is lost with the spacecraft.
The Solar Dynamics Observatory (SDO) is a NASA mission which has been observing the Sun since 2010. Launched on 11 February 2010, the observatory is part of the Living With a Star (LWS) program.
Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission began in February 2007 as a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles. The name of the mission is an acronym alluding to the Titan Themis.
Spacecraft electric propulsion is a type of spacecraft propulsion technique that uses electrostatic or electromagnetic fields to accelerate mass to high speed and thus generating thrust to modify the velocity of a spacecraft in orbit. The propulsion system is controlled by power electronics.
The exploration of Jupiter has been conducted via close observations by automated spacecraft. It began with the arrival of Pioneer 10 into the Jovian system in 1973, and, as of 2024, has continued with eight further spacecraft missions in the vicinity of Jupiter and two more en route. All but one of these missions were undertaken by the National Aeronautics and Space Administration (NASA), and all but four were flybys taking detailed observations without landing or entering orbit. These probes make Jupiter the most visited of the Solar System's outer planets as all missions to the outer Solar System have used Jupiter flybys. On 5 July 2016, spacecraft Juno arrived and entered the planet's orbit—the second craft ever to do so. Sending a craft to Jupiter is difficult, mostly due to large fuel requirements and the effects of the planet's harsh radiation environment.
In geophysics, a magnetic anomaly is a local variation in the Earth's magnetic field resulting from variations in the chemistry or magnetism of the rocks. Mapping of variation over an area is valuable in detecting structures obscured by overlying material. The magnetic variation in successive bands of ocean floor parallel with mid-ocean ridges was important evidence for seafloor spreading, a concept central to the theory of plate tectonics.
Magsat was a NASA / USGS spacecraft, launched on 30 October 1979. The mission was to map the Earth's magnetic field, the satellite had two magnetometers. The scalar and vector magnetometers gave Magsat a capability beyond that of any previous spacecraft. Extended by a telescoping boom, the magnetometers were distanced from the magnetic field created by the satellite and its electronics. The satellite carried two magnetometers, a three-axis fluxgate magnetometer for determining the strength and direction of magnetic fields, and an ion-vapor/vector magnetometer for determining the magnetic field caused by the vector magnetometer itself. Magsat is considered to be one of the more important Science/Earth-orbiting satellites launched; the data it accumulated is still being used, particularly in linking new satellite data to past observations.
Aditya-L1 is a coronagraphy spacecraft for studying the solar atmosphere, designed and developed by the Indian Space Research Organisation (ISRO) and various other Indian Space Research Institutes. It is orbiting at about 1.5 million km from Earth in a halo orbit around the Lagrange point 1 (L1) between the Earth and the Sun, where it will study the solar atmosphere, solar magnetic storms, and their impact on the environment around the Earth.
Soil Moisture Active Passive (SMAP) is a NASA environmental monitoring satellite that measures soil moisture across the planet. It is designed to collect a global 'snapshot' of soil moisture every 2 to 3 days. With this frequency, changes from specific storms can be measured while also assessing impacts across seasons of the year. SMAP was launched on 31 January 2015. It was one of the first Earth observation satellites developed by NASA in response to the National Research Council's Decadal Survey.
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.
FR-1 was the second French satellite. Planned as the first French satellite, it was launched on 6 December 1965—ten days after the actual first French satellite, Astérix—by an American Scout X-4 rocket from the Western Range at Vandenberg Air Force Base. The scientific satellite studied the composition and structure of the ionosphere, plasmasphere, and magnetosphere by measuring the propagation of very low frequency (VLF) waves and the electron density of plasma in those portions of the Earth's atmosphere. FR-1's VLF receiver operated until 26 August 1968. FR-1 remains in orbit as of 2023.
Galileo was an American robotic space probe that studied the planet Jupiter and its moons, as well as the asteroids Gaspra and Ida. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was delivered into Earth orbit on October 18, 1989, by Space ShuttleAtlantis, during STS-34. Galileo arrived at Jupiter on December 7, 1995, after gravitational assist flybys of Venus and Earth, and became the first spacecraft to orbit an outer planet.
