Advanced Composition Explorer The objective of ACE is to collect observations of particles of solar, interplanetary, interstellar, and galactic origins, spanning the energy range from that of KeV solar wind ions to galactic cosmic ray nuclei up to 600 MeV/nucleon. It is a major mission in the Explorer program. (Launched 1997 August 25) Cassini The Cassini Mission will do a detailed study of Saturn, its rings, its magnetosphere, its icy satellites, and its moon Titan. The Cassini Orbiter’s mission consists of delivering a probe (called Huygens, provided by the European Space Agency) to Titan, and then remaining in orbit around Saturn for detailed studies of the planet and its rings and satellites. Cassini will arrive at Saturn on 2004 July 1. (Launched 1997 October 15) Chandra X-ray Observatory Chandra is the third of NASA’s Great Observatories, after the Hubble Space Telescope and the Compton Gamma Ray Observatory. It is performing an exploration of the hot turbulent regions in space with images 25 times sharper than previous x-ray pictures. Chandra’s improved sensitivity make it possible to perform detailed studies of black holes, supernovas, and dark matter, and increase our understanding of the origin, evolution, and destiny of the universe. (Launched 1999 July 23) Cosmic Hot Interstellar Plasma Spectrometer CHIPS will use an extreme ultraviolet spectrograph during its one-year mission to study the “Local Bubble,” a tenuous cloud of hot gas surrounding our Solar System that extends about 300 light- years from the Sun. Scientists believe that the million-degree gas in this region is generated by supernovae and stellar winds from hot stars, but want to better understand the origins and cooling of this gas, and apply knowledge of these processes to the study of other galaxies beyond our Milky Way. CHIPS was selected in September 1998 as one of the first two University-Class Explorer (UNEX) missions. (Launched 2003 January 12) Cluster Cluster is a European Space Agency program with major NASA involvement. The four Cluster spacecraft carry out three-dimensional measurements in the Earth’s magnetosphere, covering both large- and small-scale phenomena in the sunward and tail regions. The first 2 spacecraft were launched on 2000 July 16; the 2nd pair were launched on 2000 August 9. Fast Auroral Snapshot Explorer The FAST small explorer (SMEX) studies the detailed plasma physics of the Earth’s auroral regions. Ground support “campaigns” coordinate satellite measurements with ground observations of the Aurora Borealis, commonly referred to as the “Northern Lights”. The science instruments on board FAST are helping scientists to learn about the interaction of the solar wind with Earth’s magnetosphere. (Launched 1996 August 21) Far Ultraviolet Spectroscopic Explorer FUSE is the first in the series of Medium-class Explorer missions of the Explorer programand represents the next generation, high-orbit, ultraviolet space observatory covering the wavelength range of 900 to 1200 A. This range provides an opportunity to answer important questions about many types of astrophysical objects, such as the nuclear regions of active galaxies and quasars, massive stars, supernovae, planetary nebulae, and the outer atmospheres of cool stars and planets. (Launched 1999 June 24) Galileo The Galileo spacecraft was named in honor of Galileo Galilei, the Italian Renaissance scientist who discovered Jupiter’s major moons in 1610. In the years since astronauts deployed Galileo from the cargo bay of Space Shuttle Atlantis in 1989, the mission has produced a string of discoveries about asteroids, a fragmented comet, Jupiter’s atmosphere, Jupiter’s magnetic environment, and especially about the geologic diversity of Jupiter’s four largest moons. The flight team for Galileo ceased operations on 2003 February 28 after a final playback of scientific data from the robotic explorer’s tape recorder. Galileo will coast, unattended, before transmitting a few hours of science measurements in real time, leading up to a Sept. 21 plunge into Jupiter’s atmosphere. (Launched 1989 October 18; Jupiter arrival 1995 December 7) Genesis The Genesis mission is designed to collect samples of the charged particles in the solar wind and return them to Earth laboratories for detailed analysis. It will return the samples of isotopes of oxygen, nitrogen, the noble gases, and other elements to an airborne capture in the Utah desert in 2004 September. Such data are crucial for improving theories about the origin of the Sun and the planets, which formed from the same primordial dust cloud. Genesis was selected in October 1997 as the 5th Discovery mission. (Launched 2001 August 8) Geotail The Geotail mission is a collaborative project undertaken by the Japanese Institute of Space and Astronautical Science (ISAS) and NASA. Its primary objective is to study the tail of the Earth’s magnetosphere. The information gathered is allowing scientists to model and more accurately predict Sun-Earth interactions and their effects on space exploration, communications and technology systems. (Launched 1992 July 24) High Energy Transient Explorer – 2 HETE-2′s prime objective is to carry out a multiwavelength study of gamma ray bursts (GRBs) with UV, X-ray, and gamma ray instruments. A unique feature of the mission is its capability to localize bursts with several arcsecond accuracy, in near real-time aboard the spacecraft. The original HETE spacecraft was lost as a result of a launch failure on 1996 November 4. (Launched 2000 October 9) Hubble Space Telescope The Hubble Space Telescope is an operational program that continues to generate major scientific discoveries. Meanwhile, new science instruments are being developed and will be delivered and installed on-orbit via the space shuttle in 2000 and 2003. HST’s instruments provide scientific data in the ultraviolet, visible, and near infrared regions of the electromagnetic spectrum. (Launched 1990 April 24) Imager for Magnetopause-to-Aurora Global Exploration IMAGE is a mission to study the global response of the magnetosphere to the changes in the solar wind. Major changes occur to the configuration of the magnetosphere as a result of changes in and on the sun, which in turn change the solar wind. IMAGE uses neutral atom, ultraviolet, and radio imaging techniques to detect and gather data on these changes. (Launched 2000 March 25) International Gamma-Ray Astrophysics Laboratory The European Space Agency’s INTEGRAL mission is a gamma-ray observatory that seeks to unravel the secrets of the highest-energy – and therefore the most violent – phenomena in the Universe. NASA funds U.S. science participation on the mission. (Launched 2002 October 17) Microwave Anisotropy Probe MAP is a MIDEX class Explorer mission to probe conditions in the early universe by measuring the properties of the cosmic microwave background radiation over the full sky. Scientifically it is the successor to the highly successful Cosmic Background Explorer (COBE) mission. (Launched 2001 June 30) Mars Global Surveyor Mars Global Surveyor is returning an unprecedented amount of data regarding Mars’ surface features, atmosphere, and magnetic properties. Scientists are using the data gathered from this mission both to learn about the Earth by comparing it to Mars, and to build a comprehensive data set to aid in planning future missions. (Launched 1996 November 7) Mars Odyssey The 2001 Mars Odyssey orbiter is mapping the mineralogy and morphology of the Martian surface, and achieving global mapping of the elemental composition of the surface and the abundance of hydrogen in the shallow subsurface. (Launched 2001 April 7; Mars arrival 2001 October 24) Nozomi (formerly Planet-B) NASA provided a Neutral Mass Spectrometer (NMS) to the Japanese Institute of Space and Astronautical Science (ISAS), for launch to the planet Mars aboard the Japanese Planet-B spacecraft. After launch, Japan renamed the spacecraft Nozomi, or “hope”. The project objective is to study the structure and dynamics of the atmosphere and ionosphere of Mars, including any interactions with the solar wind. (Launched 1998 July 3) Polar Polar is the second of two NASA spacecraft in the Global Geospace Science (GGS) initiative and part of the ISTP Project. GGS is designed to improve greatly the understanding of the flow of energy, mass and momentum in the solar-terrestrial environment with particular emphasis on “geospace”. (Launched 1996 February 24) Reuven Ramaty High Energy Solar Spectroscopic Imager RHESSI observes x-rays and gamma-rays from the Sun, to study particle acceleration and energy release in solar flares. (Launched 2002 February 5) Rossi X-ray Timing Explorer RXTE studies variability over time in the emission of X-ray sources, with moderate spectral resolution. This time behavior is a source of important information about processes and structures in white-dwarf stars, X-ray binaries, neutron stars, pulsars and black holes. (Launched 1995 December 30) Solar, Anomalous, and Magnetospheric Particle Explorer SAMPEX is investigating the composition of local interstellar matter and solar material and the transport of magnetospheric charged particles into the Earth’s atmosphere. SAMPEX was the first Small Explorermission. (Launched 1992 July 3) Solar and Heliospheric Observatory SOHO, a joint venture of the European Space Agency and NASA, is a solar observatory studying the structure, chemical composition, and dynamics of the solar interior; the structure (density, temperature and velocity fields) and dynamics of the outer solar atmosphere; and the solar wind and its relation to the solar atmosphere. SOHO is an element of both the ESA Solar Terrestrial Science Programme (STSP) and NASA’s ISTP Project. (Launched 1995 December 2) Stardust Stardust is a comet sample return mission having the distinction of being the first sample return mission from beyond the Earth-Moon system. Stardust will collect interstellar dust, then encounter Comet P/Wild 2 in January 2004, collecting comet dust and possibly imaging the nucleus at resolutions 10 times better than Giotto did at Halley. The spacecraft will return to Earth in January 2006 and drop off the sample return capsule. (Launched 1999 February 7) Submillimeter Wave Astronomy Satellite SWAS is part of the Small Explorer program. SWAS studies the chemical composition, energy balance and structure of interstellar clouds and the processes that lead to the formation of stars and planets. (Launched 1998 December 5) Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics TIMED explores the Earth’s Mesosphere and Lower Thermosphere (60-180 kilometers up), the least explored and understood region of our atmosphere. It is known that the global structure of this region can be perturbed during stratospheric warmings and solar-terrestrial events, but the overall structure and dynamics responses of these effects are not understood. Advances in remote sensing technology employed by TIMED will enable us to explore this region on a global basis from space. (Launched 2001 December 7) Transition Region and Coronal Explorer A mission of the Small Explorer program, TRACE observes the effects of the emergence of magnetic flux from deep inside the Sun to the outer corona with high spatial and temporal resolution. (Launched 1998 April 1) Ulysses The Ulysses Mission is the first spacecraft to explore interplanetary space at high solar latitudes, orbiting the Sun nearly perpendicular to the plane in which the planets orbit. The spacecraft and spacecraft operations team are provided by the European Space Agency (ESA); the launch of the spacecraft, radio tracking, and data management operations are provided by NASA. Scientific experiments are provided by investigation teams both in Europe and the USA. (Launched 1990 October 6) Voyager Interstellar Mission The VIM is an extension of the Voyager primary mission that was completed in 1989 with the close flyby of Neptune by the Voyager 2 spacecraft. This extended mission is continuing to characterize the outer solar system environment and search for the heliopause boundary, the outer limits of the Sun’s magnetic field and outward flow of the solar wind. (Voyager 1 launched 1977 September 5; Voyager 2 launched 1977 August 20) Wind Wind is the first of two NASA spacecraft in the Global Geospace Science initiative and part of the ISTP Project. Wind studies the solar wind and its impact on the near-Earth environment. (Launched 1994 November 1) XMM-Newton XMM-Newton is an X-ray astrophysics observatory developed by the European Space Agency, with U.S. participation. This facility-class observatory, with an anticipated lifetime of ten years, enables astronomers to conduct sensitive X-ray spectroscopic observations of a wide variety of cosmic sources. (Launched 1999 December 10) Space InfraRed Telescope Facility(Launch: 2003 April) SIRTF, the last of NASA’s four Great Observatories, will be a cryogenically cooled observatory to conduct infrared astronomy from space. SIRTF will consist of a 0.85-meter diameter telescope and three scientific instruments capable of performing imaging and spectroscopy in the 3-180 micron wavelength regime. Incorporating the latest in large-format infrared detector array technology, SIRTF will do for infrared astronomy what the Hubble Space Telescope has done in its unveiling of the visible universe. Galaxy Evolution Explorer(Launch: 2003 April) GALEX was selected in 1997 October as a Small Explorer mission. GALEX will use an ultraviolet telescope during its two-year mission to explore the origin and evolution of galaxies and the origins of stars and heavy elements. GALEX will detect millions of galaxies out to a distance of billions of light years and also will conduct an all-sky ultraviolet survey. Mars Exploration Rovers(Launch: 2003 May/July) In 2003, two powerful new Mars rovers will be on their way to the red planet. With far greater mobility than the 1997 Mars Pathfinder rover, these robotic explorers will be able to trek up to 100 meters (about 110 yards) across the surface each Martian day. Each rover will carry a sophisticated set of instruments that will allow it to search for evidence of liquid water that may have been present in the planet’s past. The rovers will be identical to each other, but will land at different regions of Mars. Mars Express/ Analyzer of Space Plasmas and Energetic Atoms(Launch: 2003 June) NASA is participating in a mission planned by the European Space Agency and the Italian space agency called Mars Express, which will explore the atmosphere and surface of Mars from polar orbit. NASA’s involvement includes joint development of the radar instrument with the Italian space agency; support of U.S. science co-investigators; coordination of radio relay systems to make sure that different spacecraft will operate with each other; a hardware contribution to the energetic neutral atoms analyzer instrument; and the provision of backup tracking support during critical mission phases by NASA’s Deep Space Network. Our contribution to the energetic neutral atoms analyzer instrument is called ASPERA-3. ASPERA-3 was selected as a Discovery mission of opportunity; the complete instrument will study the interaction between the solar wind and the atmosphere of Mars, and attempt to find out what happened to the large amount of water that was once on Mars. The co-investigator being funded by NASA is Dr. David Winningham of the Southwest Research Institute, San Antonio, TX. Two Wide-Angle Imaging Neutral-Atom Spectrometers(Launch: 2003 July) Selected in October 1997 as an Explorers mission of opportunity, TWINS will provide stereo imaging of the Earth’s magnetosphere, the region surrounding the planet controlled by its magnetic field and containing the Van Allen radiation belts and other energetic charged particles. TWINS will enable three-dimensional global visualization of this region, which will lead to greatly enhanced understanding of the connections between different regions of the magnetosphere and their relation to the solar wind.