FUTURE MISSION CONCEPT STUDIES SELECTED

19 proposals have been selected for new innovative mission concepts in space physics. The 19 were selected from 70 proposals submitted in response to a NASA Research Announcement (NRA) released in February 1996, which solicited proposals for mission concept studies for missions that could be ready to start between 1999 and 2005.

The selected studies are listed below with the name of the Principal Investigator, Institution and a brief description of the mission concept.

• A Low Cost Mercury Orbiter Mission -- Daniel N. Baker, University of Colorado, Boulder -- This mission would carry out a comprehensive investigation of the plasma and magnetic field environment, the atmosphere, and the surface of Mercury by applying recent advances in spacecraft and instrument miniaturization and innovative propulsion systems.

• STEREO: A Solar-Terrestrial Event Observer -- Guenter E. Brueckner, Naval Research Laboratory, Washington, DC -- This mission would provide stereo and 3-D images of the heliosphere and of the Earth's magnetosphere using three spacecraft (one in Earth orbit and two in orbit around the Sun) and advanced image processing techniques.

• Study for an Auroral Multi-Probe Satellite Mission (AMPS) -- Cynthia A. Cattell, University of Minnesota -- This mission would enable the exploration and understanding of structural and dynamic features of auroral acceleration using three nearly identical spacecraft in nearly identical orbits. The use of the three spacecraft will allow the separation of temporal and spatial variations parallel and perpendicular to the magnetic field over a range of spatial scales.

• Development of a Radio Tomography Mission for Investigation of the Earth's Magnetosphere -- Robert E. Ergun, University of California, Berkeley -- This mission would produce two dimensional high resolution images of the Earth's magnetosphere using radio tomography (like a CAT scan of the Earth's magnetosphere) using sixteen small 30 kg satellites, launched by a single launch vehicle, into orbit around the Earth.

• Solar Bolometric Imager -- Peter V. Foukal, Cambridge Research & Instrumentation, Inc. -- A Small Explorer-class mission that would examine how the solar irradiance between 0.25 and 5 microns, which affects Earth's climate directly, varies over the solar surface and would provide insight into the causes of this "Sun-Earth Connection". The small 25 cm diameter telescope would utilize recent technology advances in uncooled infrared detector arrays developed by the DOD modified with a special coating to allow uniform response over the wavelength range required.

• High Resolution X-ray Explorer (HIREX) -- Leon Golub, Harvard-Smithsonian Astrophysical Observatory -- An X-ray solar observatory with three telescopes (with up to 1 m diameter primary mirrors) would provide both ultra-high resolution and a large dynamic range in spatial and spectral coverage allowing for measurement of processes ranging from global scale coronal disruptions to micro-scale instabilities. In order to reduce the costs of such a mission, HIREX would use advanced light-weight mirrors, a light-weight, deployable, 40 m long, telescope structure, on-orbit focus and alignment, and real-time image stabilization.

• Multiple Tethered Satellites for Ionospheric Studies -- Roderick A. Heelis, University of Texas, Dallas -- This mission would advance our understanding of ionosphere-thermosphere-magnetosphere coupling processes using multiple tethered satellites. The tether, which would be used to control the vertical separations of the spacecraft, would allow the study of vertical gradients simultaneously with sampling along the horizontal satellite track.

• SIRA Solar Imaging Radio Array -- Michael L. Kaiser, NASA/Goddard Space Flight Center -- A fleet of spacecraft would make images of solar radio emissions which would provide new information about shock wave mechanisms and acceleration processes associated with coronal mass ejections and solar flares. The fleet of 16 micro satellites would function as a space based interferometer and fly in a 10 km diameter formation in solar orbit near the Earth.

• Stereo X-Ray Corona Imager -- Paulett C. Liewer, Jet Propulsion Laboratory -- A single spacecraft/single instrument mission that would produce stereo and 3D X-ray images and movies of the sun's corona using advanced image processing technologies on the spacecraft along with data from other space-based and ground-based solar observations.

• Maxwell, Faraday, and Vlasov: 3 Direct Measurements of Current -- Kristina Lynch, University of New Hampshire -- A small secondary payload mission that would make quantitative measurements of auroral electrical currents. The payload would consist of a mother spacecraft and 36 small (6 cm diameter) free-flying autonomous spacecraft utilizing new technologies in advanced miniaturized sensors, integrated microelectronics, and miniature spacecraft systems.

• Multi-Point Magnetospheric Reconnaissance Imaging Visualization of Ion Dynamics, Evolution, Origins, and Structure -- Donald G. Mitchell, Applied Physics Laboratory -- This mission would create accurate 3-D images of the magnetosphere by making simultaneous multi-point observations of the energetic neutral atoms and ultraviolet emissions using multiple, small spacecraft.

• Giant Platforms for Cosmic Ray Observations above the Atmosphere -- Dietrich Muller, University of Chicago -- This mission would determine the composition and energy spectrum of high-energy cosmic rays and look for and characterize the upper limits of acceleration by supernova shock waves, and possibly the source of higher energy particles by using a very large light-weight cosmic ray detector on a 100-day stratospheric balloon flight.

• Solar Polar Sail Mission -- Marcia Neugebauer, Jet Propulsion Laboratory -- This mission would study the physics and dynamics of coronal mass ejections and other eruptions from the surface of the sun using solar sails to propel a spacecraft into a circular polar orbit around the sun.

• Orbiting Array of Wide-angle Light Collectors (OWL): A Pair of Earth Orbiting Eyes to Study Air Showers Initiated by >1020 eV Quanta -- Jonathan F. Ormes, NASA/Goddard Space Flight Center -- This mission would image the faint air showers produced by Nature's most energetic particles as they move through the Earth's atmosphere at the speed of light. The origin of these energetic particles is unknown and determining the origin could shed light on conditions in the early universe. Two spacecraft, each with an array of seven light-weight, deployable light concentrators (each 3 meters in diameter), would be placed in Earth orbit.

• Design Study for a Global Magnetospheric Dynamics Mission -- Christopher T. Russell, University of California, Los Angeles -- This mission would explore the fundamental microphysical processes in the Earth's magnetosphere using a fleet of 4 spacecraft in a tetrahedral formation and propelled by solar electric propulsion.

• SOLAR - A Mission To Measure The Quadrapole Moment Of The Sun -- David E. Smith, NASA/Goddard Space Flight Center -- This mission would measure the perturbations on a spacecraft's orbit caused by small variations in the gravity of the sun. These perturbations provide information on the nature of the deep solar interior. A small spacecraft, weighing only about 45 pounds, that would be put into an orbit around the sun between the Earth and Mercury and use a laser tracking system to measurement the perturbations. This system would also be used for optical communications with the ground stations on Earth.

• Lower Ionosphere Thermosphere Explorer -- Stanley C. Solomon, University of Colorado, Boulder -- This would be a low cost (< $20 M class) exploratory mission lasting only 2-3 months to make direct in-situ measurements of the density, temperature and composition of the Earth's lower thermosphere from 120-200 km, including the region below 140 km which is the least measured and least understood region of the Earth's atmosphere.

• The Magnetospheric Mapping Mission -- Harlan E. Spence, Boston University -- This mission would measure the Earth's vector magnetic field from 5 to 10 Re (Re is the radius of the Earth.) and produce continuous sequences of 3-D images of the magnetosphere by using more than 100 micro-satellites with advanced detectors and a novel data telemetry approach.

• Advanced Calorimeter for Composition of Elements on the Space Station (ACCESS) to Study >10 TeV Cosmic Rays -- John P. Wefel, Louisiana State University -- A large International Space Station instrument to find the composition and energy spectrum of high-energy cosmic rays, to look for and characterize the upper limits of acceleration by supernova shock waves, and possibly the source of higher energy particles.