CSR conducts an active program of research in astronomy, astrophysics, space science, and related technology, with emphasis on investigations in support of various National Aeronautical and Space Administration (NASA) flight missions. Specific areas of research include gravity-wave, X-ray, optical, radio, and radar astronomy; theoretical and experimental space plasma physics; planetary surfaces and atmospheres; and the space life sciences. CSR is heavily involved in several ongoing or upcoming NASA missions and supports MIT participation in several major facilities. Research carried out in CSR is reported by the following departments: Physics, Earth Atmospheric & Planetary Sciences, and Aeronautics & Astronautics.
HIGHLIGHTS OF THE YEAR
The orbiting Bruno B. Rossi X-ray Timing Explorer (RXTE), named in honor of late MIT Prof. Rossi, has successfully completed 18 months of observations of compact objects in our galaxy (neutron stars and black holes) as well as active galactic nuclei through the variability of the intensities of the X-rays emitted by these objects. The All Sky Monitor (ASM), one of two instruments prepared at CSR, monitors the intensities of about 70 cosmic X-ray sources; the results have revealed orbital periods, super-orbital periods, state changes, and bursts (Prof. Bradt, Drs. Levine, R. Remillard, W. Cui). Intensity oscillations in the range 300 - 1000 Hz have been discovered in more than a dozen neutron-star sources (Prof. W. Lewin, Dr. Morgan, Prof. Bradt). Extensive studies of the black-hole systems called "microquasars" reveal quasi-periodic oscillations and explore the relation between accretion and relativistic jet formation (Drs. Morgan and Remillard). These systems as well as other black-hole systems (Dr. Cui) provide information pertaining to the angular momenta of the black holes. A puzzling neutron-star source (Cir X-1) is being studied extensively (Prof. Bradt, Dr. Levine, Dr. Morgan). Dr. V. Kaspi has established a new program to observe rotation-powered pulsars primarily at radio wavelengths but also in the X-ray and gamma-ray regions. She recently discovered a new, young, energetic pulsar and is following up with several satellite and ground-based observations. Prof. W. Lewin continues his study of quasi-periodic oscillations of low-mass X-ray binaries, having now discovered more than half of the 13 known systems in the Milky Way, and also having helped increase by 35% the known sample of gamma ray burst sources from the Compton Gamma-Ray Observatory. CSR continues participating in ASCA, a Japanese/US X-ray astronomy satellite which was launched in 1993 and carries CSR's CCD X-ray detectors (developed in collaboration with Lincoln Laboratory).
The Magellan Project consortium includes MIT, the Carnegie Institution of Washington, Harvard University, and the Universities of Arizona and Michigan. Two 6.5 meter diameter optical telescopes are being constructed on Cerro Las Camapanas in Northern Chile, the first scheduled for completion in early 1999. Construction of enclosure and fabrication of the telescope structure are nearly complete, and polishing of the mirror is underway (Profs. C. Canizares, J. Elliot & P. Schechter). Using the Michigan-Dartmouth-MIT Observatory, time delays have been measured for the multiple images of a gravitationally lensed quasar, giving a new estimate of the Hubble parameter (Profs. J. Hewitt & P. Schechter).
The interplanetary plasma group monitors solar wind conditions from three spacecraft, two near Earth (IMP 8 and WIND) and one at 52 Astronomical Units (Voyager 2). A clear signature of the recent solar minimum was observed at Voyager 2, a surprise given the large distance. IMP 8 and WIND are being used to trace the progress of eruptions on the Sun as they move toward Earth, in hopes that space weather events, which can affect satellites, terrestrial communications and electric power grids, can be better forecast in the future. (Prof. J. Belcher, Drs. A. Lazarus, J. Richardson, J. Steinberg, Ms. K. Paularena).
Analysis of the anomalous microwave scattering properties of the Venus highlands are directed at finding an explanation for the variations in altitude of the low-emissivity behavior observed there. If this is related to the condensation temperature of tellurium, as we believe, these variations reflect variations in surface temperature at a given altitude (Prof. G. Pettengill & Dr. P. Ford).
The joint Caltech/MIT LIGO (Laser Interferometer Gravitational-wave Observatory) Project, for the detection and study of gravitational radiation from celestial sources, is now 40% complete. At the Hanford, Washington site the building foundations and structures were built, and beam tube fabrication and installation is underway. At the Livingston, Louisiana site, the grading is complete and has settled, permitting construction to commence. The detector design is nearing completion; sample mirrors of 20 cm diameter and 1 nm figure have been polished and the coating technology developed to maintain this figure. The Phase Noise Interferometer at MIT has achieved "world's best" measurement of phase noise, splitting an optical fringe to one part in a billion. (Prof R. Weiss & Dr. D. Shoemaker)
Theoretical investigations include: supercomputer simulations of large scale structure in the universe (Prof. E. Bertschinger) and of the hydrodynamics of binary star coalescence (Prof. F. Rasio); work on the origins and dynamical evolution of extrasolar planetary systems (Prof. F. Rasio); studies of the evolutionary histories of collapsed stars (white dwarfs, neutron stars, and black holes) in binary systems, including binary millisecond pulsars (Profs. S. Rappaport & P. Joss); investigations of the ages of the oldest stars in globular clusters and the implications for the age of the universe, supernovae in binary star systems and detectability of brown dwarf stars in the Galaxy (Prof. Joss). Closer to Earth, a new innovative theory of multiscale intermittent turbulence has been developed for the description of the Earth's magnetotail. (Dr. T. Chang).
In the area of aerospace technology, an Advanced Dynamic Load Sensors Experiment has been conducted on the MIR space station to assess the impact of human space activity on the space station (Prof. D. Newman), and a program of flight simulator research on terrain situation awareness cockpit displays has been initiated (Dr. C. Oman). Prof. C. Counselman has developed a new kind of antenna for satellite geodesy, which promises to improve substantially the accuracy and speed of geodesy and navigation using the Global Positioning System.
UPCOMING PROGRAMS
The High Energy Transient Experiment (HETE), to search for gamma ray burst sources, was successfully delivered to NASA by CSR, but the satellite was lost following failure of the launch vehicle. NASA has now approved rebuilding the satellite for launch in 1999 (Dr. G. Ricker). New cameras are also now being built for the next Japanese/U.S. X-ray mission, Astro-E, to be launched in 1999 (Drs. G. Ricker & M. Bautz).
AXAF is a major NASA mission of the "great observatory" series, scheduled for launch in 1998. Two of the four major instruments, the High-Energy Transmission Grating Spectrometer (Prof. C. Canizares) and the AXAF Charge-Coupled Device (CCD) Imaging Spectrometer (Drs. Ricker & M. Bautz), have now been successfully completed and delivered to NASA. Extensive calibration of the state-of-the-art instruments is underway. The first set of AXAF observations are being planned. CSR is also active in the AXAF Science Center, which will oversee the operation of AXAF during the mission (Prof. Canizares).
An experiment for the 1998 "Neurolab" mission is in active development and an extension of the experiment was approved for flight on the International Space Station. Ground based research continues on human spatial orientation in real and virtual environments, EVA biomechanics, and a new research initiative on artifical gravity physiology and human factors (Profs. L. Young & D. Newman, Dr. C. Oman).
Prof. Pettengill and Dr. Peter Ford are involved in the Mars Orbiter Laser Altimeter Experiment, onboard the Mars Global Surveyor spacecraft due to be placed in orbit around the red planet in September 1997. This experiment will yield a precision global topographic map of Mars.
More information about this center can be found on the World Wide Web at the following URL: http://space.mit.edu
Claude R. Canizares