Working Papers Astronomy and Astrophysics Panel Reports (1991) / Chapter Skim
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UV-Optical from Space
UV-Optical from Space
Pages 75-106
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From page 75... ...
Operation beyond Low Earth Orbit would lead to large gains in the science return and substantial savings in construction and operational costs. Finally, the program has as its goal a telescope of astonishing power, the 16 m NGST (Next Generation Space Telescope)
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From page 76... ...
Small: Small Explorer missions: A UY low spatial resolution all-sky imaging survey would return excellent science in this class. The UV survey would be particularly valuable for mapping diffuse UV emission from the hot and cold ISM.
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From page 77... ...
They require adequate support. Technologies for the Next Century: The Next-Century Program: Explorers, interferometers and large space telescopes depend critically on technology developments.
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From page 78... ...
Large space telescopes that combine high spatial resolution with low backgrounds are essential for tackling this problem. In general, the spatial resolution that will become available with HST, with the 6 m and ultimately with the 16 m will be crucial for unravelling some of the complex structural and dynamical characteristics of protostellar structures.
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From page 79... ...
Larger aperture space telescopes such as LST will result in very substantial increases in the number of sources that can be studied. The physical conditions in the absorbing interstellar medium of galaxies could be directly related to other observable properties of the host galaxy.
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From page 80... ...
An excellent example of the significance of the Magellanic Clouds for stellar evolution was furnished by SN1987A, an event to which space astronomy was able to respond remarkably well, and which produced a major leap forward in our knowledge of the evolution of massive stars. High angular resolution observations are of special importance in the study of massive stars (such as R136a in the 30 Dor star formation region)
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From page 81... ...
This technique also has the potential for allowing valuable constraints to be placed on the age and metallicity distribution in the stellar population. While HST, in conjunction with observations from large ground-based telescopes, will probably allow precise measurements out to Coma, extension beyond that will require larger space telescopes.
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From page 82... ...
A new generation of UV-Visible space telescopes would place our understanding of active galactic nuclei on a firm footing and should help us to develop theories of galaxy evolution that parallel existing theories of stellar evolution. A 108 Me black hole has a size comparable with that of the Earth's orbit.
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From page 83... ...
The background at 3-4 Am with a passively-cooled space telescope will be ~ 10-6 of that from the ground, a substantially greater gain than the 10-3 decrease expected in the 1-2 Am region accessible to HST. The light from the stellar populations in very distant high-z galaxies will be redshifted into this region, as will many of the important emission lines.
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From page 84... ...
Several of these problems have been addressed earlier, particularly the determination of the Hubble constant and the limits on ages from age-dating the oldest stellar populations. A key issue is the comparison of the cosmological clock with the stellar nuclear clock.
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From page 85... ...
Many of these techniques require high spatial resolution and so need space telescopes, such as HST, LST and interferometers. Such telescopes will also have a particular role to play in investigations of the evolution of structure with time, both directly at high redshift and through measurement of QSO absorption lines.
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From page 86... ...
The LST would be a 6 m-class passively-cooled UV-Visible-IR space telescope. Substantial gains in capability and science productivity are possible through implementation of developing technologies, and through its location in High Earth Orbit (HEO)
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From page 87... ...
High performance optics are a central component of all instruments in this wavelength range. The scientific goals demand more difficult, larger and smoother optics.
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From page 88... ...
The panel strongly recommends that a 6 m-class telescope be launched in the first decade of the next century. Substantial gains in capability can be realized at a cost comparable to HST.
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From page 89... ...
It is clear that major issues can be addressed in the areas of the ISM and its evolution with time, in stellar astrophysics, in star forming regions, in studies of activity in galaxies, and in stellar population studies. In this latter area thresholds are passed that allow for the study of populations in nearby galaxies that will establish how such galaxies form and evolve.
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From page 90... ...
IV-16 Cassegrain Mirror: ~\\ Reflective and Insulated side (FOSR + MLI) ~ _ ~ J.(,:: 1 ~ AL ~ 11 ~ ~ ~ ~ ~ O Scientific -- Instruments Primary Mirror— am dia.
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From page 91... ...
Earth and Sun angles of 90°are realistic in HEO. Fourth, the instruments can be comparable to those in HST, and could well be modest developments from the HST Second and Third Generation systems.
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From page 92... ...
It then provides a natural overlap in resolution with data from ground-based telescopes and from space telescopes in other wavebands. While initial studies may focus on the development of such a telescope as part of the Lunar Outpost program, these studies should be generic in nature.
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From page 93... ...
They will continue to do so. The panel strongly recommends that the Delta-class Explorer program be enhanced so as to allow more frequent missions with shorter development times.
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From page 94... ...
The scientific objectives would include understanding the physical processes occuring in accretion disks, such as boundary layer phenomena, and the conversion of magnetic energy to relativistic particles and heat, the characteristics of the matter and radiation environment around highly condensed stars, the physics of the activity on stellar surfaces and within their coronae, and, on longer timescales, the dynamics and physics of the activity in active galactic nuclei. Simultaneous observations by co-aligned modest-sized instruments on the same satellite in HEO will permit uninterrupted long-duration observations of the intrinsic variability of plasma at 104 °K to 108 °K in these sources.
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From page 95... ...
The deep involvement in these programs of the science community at universities, labs and centers is crucial for the long-term vitality of the field. Explorers provide a means of training and of developing the technical and management skills that are needed if the UV-Visible-IR space science community is to continue as a vital element of the space science program.
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From page 96... ...
This appears to be scientifically very meritorious and is well-matched to Pegasus or Scout capabilities. While there is a clear need for a 1" resolution point-source survey that matches the multicolor Schmidt surveys available from the ground, a survey at low spatial resolution that is particularly sensitive to low surface brightness diffuse emission would pay substantial scientific dividends.
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From page 97... ...
The results from an increased Explorer program, HST, and the other Great Observatories will place substantial pressure on ground-based facilities. This will be particularly the case for spectroscopic observations of faint sources.
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From page 98... ...
the physical processes that control the origin and evolution of galaxies, namely the examination of ISM and stellar processes that influence it, and (iii) the physical processes that control the origin and evolution of stars and solar systems, in particular study of the cold clouds in the interstellar medium, and of the dynamics of the formation process itself.
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From page 99... ...
is a high resolution, high sensitivity spectrograph that will incorporate several advances over first generation Space Telescope instruments. Its availability on HST will result in substantial gains in productivity.
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From page 100... ...
Fundamental discoveries have been made in nearly every area of observational research, including planetary astronomy, stellar evolution, atmospheres and chromospheres, the physics of the interstellar medium, stellar populations and galaxy evolution, active galactic nuclei and the intergalactic medium. Barring significant degradation of current capabilities, IUE will continue to provide a valuable complement to the scientific return from HST for a relatively modest annual operating cost.
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From page 101... ...
The Astro mission is expected to make about 250 paintings, yielding more than a thousand measurements on astronomical sources. Astro was conceived during an era when space science was focused on Shuttle missions, and it was expected to have a multi-mission lifetime.
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From page 102... ...
Substantial future progress in space telescopes and instrumentation will require technological advances. A wide variety of demanding technologies are needed for state-of-the-art telescopes and instruments in the UV-Visible-IR wavelength region.
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From page 103... ...
Such continuing capability allows for a well-planned transition and allows for contingency in case of delays. The lunar outpost program is ambitious, as it should be, but its impact on space science and the potential for damaging a vibrant scientific program which has considerable value for the scientific base of the nation should not be underestimated.
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From page 104... ...
These telescopes have great scientific merit, and represent ambitious, but appropriate goals for the Lunar Outpost. Technology development towards these goals is needed and timely, provided emphasis is given in the early phases to demonstration projects of technologies that have broad utility for space science missions.
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From page 106... ...
INTERFEROMETRY PANEL STEPHEN RIDGWAY, National Optical Astronomy Observatories, Chair ROBERT W WILSON, AT&T Bell Laboratories, Vice-Chair MITCHELL C
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