Space Probes
Remote Explorers

Operating Missions

Solar System

Name Agency Launch Date Orbit Mission Overview
ACE NASA 1997 L1 (Sun-Earth) Determine and compare the isotopic and elemental composition of several distinct samples of matter, including the solar corona, the interplanetary medium, the local interstellar medium, and Galactic matter.
Cassini NASA / ESA (Europe) / ASI (Italy) 1997 Saturn (en route) Study of Saturn and Titan.
Genesis NASA 2001 L1 (Sun-Earth) To collect pieces of the sun, called solar wind. At L1, it unfolded its collectors and began a two-year "sunbath." Upon its return to Earth in 2004, scientists will study the solar wind samples for years to come.
Geotail NASA / ISAS (Japan) 1992 Earth/Moon System Orbit Study the dynamics of the Earth's magnetotail over a wide range of distance, extending from the near-Earth region (8 Earth radii (Re) from the Earth) to the distant tail (about 200 Re).
Mars '03 Rovers NASA 2003 Mars Twin robot geologists, the Mars Exploration Rovers, will launch toward Mars in 2003 in search of answers about the history of water on Mars.
Mars Express NASA / ESA / ASI (Italy) 2003 Mars Explore the atmosphere and surface of Mars from polar orbit. Mars Express will itself carry a small lander as well.
Mars Global Surveyor NASA 1996 Mars Over the course of a full Martian year, Surveyor will return an unprecedented amount of data regarding Mars' surface features, atmosphere, and magnetic properties.
Mars Odyssey NASA 2001 Mars Map the amount and distribution of chemical elements and minerals that make up the Martian surface. The spacecraft will especially look for hydrogen, most likely in the form of water ice, in the shallow subsurface of Mars. It will also record the radiation environment in low Mars orbit to determine the radiation-related risk to any future human explorers who may one day go to Mars.
SIRTF NASA 2003 Earth-trailing (Heliocentric) Infrared Observatory
SOHO NASA / ESA (Europe) 1995 L1 (Sun-Earth) Study the internal structure of the Sun, its extensive outer atmosphere and the origin of the solar wind, the stream of highly ionized gas that blows continuously outward through the Solar System.
Stardust NASA 1999 Comet Wild 2 (returning to Earth after successful particle collection) Dedicated solely to the exploration of a comet, and the first robotic mission designed to return extraterrestrial material from outside the orbit of the Moon.
Ulysses NASA / ESA 1990 Solar Orbit (Elliptical Polar) To reach high solar latitudes, the spacecraft was aimed close to Jupiter so that Jupiter's large gravitational field would accelerate Ulysses out of the ecliptic plane to high latitudes. After more than 12 years in flight, Ulysses has returned a wealth of data that has led to a much broader understanding of the Global Structure of the Sun's environment-the heliosphere.
Voyager NASA 1977 Fly-by of the Outer Planets - Heading into Interstellar Space The primary mission was the exploration of Jupiter and Saturn. After making a string of discoveries there -- such as active volcanoes on Jupiter's moon Io and intricacies of Saturn's rings -- the mission was extended. Voyager 2 went on to explore Uranus and Neptune, and is still the only spacecraft to have visited those outer planets. The adventurers' current mission, the Voyager Interstellar Mission (VIM), will explore the outermost edge of the Sun's domain. And beyond.
Wind NASA 1994 In a sunward, multiple double-lunar swingby orbit with a maximum apogee of 250Re during the first two years of operation. This will be followed by a halo orbit at the Earth-Sun L1 point. Provide conplete plasma, energetic particle, and magnetic field input for magnetospheric and ionospheric studies. Determine the magnetospheric output to interplanetary space in the up-stream region. Investigate basic plasma processes occuring in the near-Earth solar wind. Provide baseline ecliptic plane observations to be used in heliospheric latitudes from ULYSSES.
WMAP NASA 2001 L2 (Earth-Moon) Produce the first version a full sky map of the faint anisotropy or variations in the temperature of the cosmic microwave background radiation

Earth Orbit

Name Agency Launch Date Orbit Mission Overview
ACRIMSAT NASA 1999 Earth Orbit (Circular, Sun-Synchronous, 680 km) Active Cavity Radiometer Irradiance Monitor III (ACRIM III) instrument is to study total solar Irradiance from the Sun. ACRIMSAT data will be correlated with possible global warming data, ice cap shrinkage data, and ozone layer depletion data. It is theorized that as much as 25 percent of the Earth's total global warming may be solar in origin due to small increases in the Sun's total energy output since the last century. By measuring incoming solar radiation and adding measurements of ocean and atmosphere currents and temperatures, as well as surface temperatures, climatologists will be able to improve their predictions of climate and global warming over the next century. Energy forecasting, carbon management, public health.
Aqua NASA 2002 Earth Orbit (Circular, Sun-Synchronous, 705 km) Aqua carries six state-of-the-art instruments to observe the Earth's oceans, atmosphere, land, ice and snow covers, and vegetation, providing high measurement accuracy, spatial detail, and temporal frequency. This comprehensive approach to data collection enables scientists to study the interactions among the four spheres of the Earth system--the oceans, land, atmosphere, and biosphere.
Chandra NASA 1999 Earth Orbit (Elliptical, Perigee: 10,000 km, Apogee: 140,161 km) X-ray Observatory
CHIPS NASA 2003 Earth Orbit (Circular) CHIPS data will help scientists determine the electron temperature, ionization conditions, and cooling mechanisms of the million-degree plasma believed to fill the local interstellar bubble.
Cluster ESA (Europe) 2000 Earth Orbit (Elliptical, Polar, Perigee: 19,000 km, Apogee: 119,000 km) To investigate the small-scale structure (in three dimensions) of the Earth's plasma environment, such as those involved in the interaction between the solar wind and the magnetospheric plasma, in global magnetotail dynamics, in cross-tail currents, and in the formation and dynamics of the neutral line and of plasmoids.
FAST NASA 1996 Earth Orbit (Elliptical) It ventures high into the charged particle environment of aurorae to measure the electric and magnetic fields, plasma waves, energetic electrons and ions, ion mass composition, and thermal plasma density and temperature.
FUSE NASA 1999 Earth Orbit (Circular) Explore the Universe using the technique of high-resolution spectroscopy in the far-ultraviolet spectral region.
GALEX NASA 2003 Earth Orbit (Circular) Observe galaxies in ultraviolet light across 10 billion years of cosmic history. Such observations will tell scientists how galaxies, the basic structures of our Universe, evolve and change. Additionally, GALEX will probe the causes of star formation during a period when most of the stars and elements we see today had their origins.
HETE-2 NASA 2000 Earth Orbit (Circular) Detect and localize gamma-ray bursts.
Hubble Space Telescope NASA 1990 Earth Orbit (Circular) Optical Telescope
IMAGE NASA 2000 Earth Orbit (Elliptical Polar) Image the Earth's magnetosphere.
INTEGRAL ESA (Europe) 2002 Earth Orbit (Elliptical) Spectral measurements of gamma-ray sources, detection of gamma-ray bursts, mapping the galactic plane.
Polar NASA      
RHESSI NASA 2002 Earth Orbit (Circular) Explore the basic physics of particle acceleration and energy release in solar flares.
RXTE NASA 1995 Earth Orbit Observes the fast-moving, high-energy worlds of black holes, neutron stars, X-ray pulsars and bursts of X-rays that light up the sky and then disappear forever.
SAMPEX NASA 1992 Earth Orbit (Elliptical) Studies the energy,composition, and charge states of particles from supernova explosions in the distant reaches of the galaxy, from the heart of solar flares, and from the depths of nearby interstellar space. It also monitors closely the magnetospheric particle populations which plunge occasionally into the middle atmosphere of the Earth, thereby ionizing neutral gases and altering the atmospheric chemistry.
SWAS NASA 1998 Earth Orbit Study the chemical composition of interstellar gas clouds. The primary objective of SWAS is to survey water, molecular oxygen, carbon, and isotopic carbon monoxide emission in a variety of galactic star forming regions.
TIMED NASA 2001 Earth Orbit Study the influences of the Sun and humans on the least explored and understood region of Earth's atmosphere--the Mesosphere and Lower --> --Thermosphere/Ionosphere (MLTI).
TRACE NASA 1998 Earth Orbit (Circular) Image the solar corona and transition region at high angular and temporal resolution.
XMM-Newton ESA 1999 Earth Orbit (Elliptical) X-Ray Observatory

Last updated: 27 Feb 2004


Please contact Adam if you have questions or comments about this page. Research and image sources are provided when possible.


The images of Voyager and the surface of Mars are from the JPL web site and are used here for noncommercial, educational purposes.