11,938 research outputs found
Space Telescopes
The science of astronomy depends on modern-day temples called telescopes. Astronomers make pilgrimages to remote mountaintops where these large, intricate, precise machines gather light that rains down from the Universe. Bit, since Earth is a bright, turbulent planet, our finest telescopes are those that have been launched into the dark stillness of space. These space telescopes, named after heroes of astronomy (Hubble, Chandra, Spitzer, Herschel), are some of the best ideas our species has ever had. They show us, over 13 billion years of cosmic history, how galaxies and quasars evolve. They study planets orbiting other stars. They've helped us determine that 95% of the Universe is of unknown composition. In short, they tell us about our place in the Universe. The next step in this journey is the James Webb Space Telescope, being built by NASA, Europe, and Canada for a 2018 launch; Webb will reveal the first galaxies that ever formed
Space Telescopes
Space telescopes have been a dominant force in astrophysics and astronomy over the last two decades. As Lyman Spitzer predicted in 1946, space telescopes have opened up much of the electromagnetic spectrum to astronomers, and provided the opportunity to exploit the optical performance of telescopes uncompromised by the turbulent atmosphere. This special section of Optical Engineering is devoted to space telescopes. It focuses on the design and implementation of major space observatories from the gamma-ray to far-infrared, and highlights the scientific and technical breakthroughs enabled by these telescopes. The papers accepted for publication include reviews of major space telescopes spanning the last two decades, in-depth discussions of the design considerations for visible and x-ray telescopes, and papers discussing concepts and technical challenges for future space telescopes
Thermal and structural modeling of superinsulation
Model permits direct physical measurement of the thermal response of critical components of space telescopes, thus providing flexibility for systems studies and design changes
Detecting Life-bearing Extra-solar Planets with Space Telescopes
One of the promising methods to search for life on extra-solar planets
(exoplanets) is to detect life's signatures in their atmospheres. Spectra of
exoplanet atmospheres at the modest resolution needed to search for oxygen,
carbon dioxide, water, and methane will demand large collecting areas and large
diameters to capture and isolate the light from planets in the habitable zones
around the stars. For telescopes using coronagraphs to isolate the light from
the planet, each doubling of telescope diameter will increase the available
sample of stars by an order of magnitude, indicating a high scientific return
if the technical difficulties of constructing very large space telescopes can
be overcome. For telescopes detecting atmospheric signatures of transiting
planets, the sample size increases only linearly with diameter, and the
available samples are probably too small to guarantee detection of life-bearing
planets. Using samples of nearby stars suitable for exoplanet searches, this
paper shows that the demands of searching for life with either technique will
require large telescopes, with diameters of order 10m or larger in space.Comment: 15 pages, 6 figures, submitted to Ap.
Why Space Telescopes Are Amazing
One of humanity's best ideas has been to put telescopes in space. The dark stillness of space allows telescopes to perform much better than they can on even the darkest and clearest of Earth's mountaintops. In addition, from space we can detect colors of light, like X-rays and gamma rays, that are blocked by the Earth's atmosphere I'll talk about NASA's team of great observatories: the Hubble Space Telescope, Spitzer Space Telescope, and Chandra X-ray Observatory} and how they've worked together to answer key questions: When did the stars form? Is there really dark matter? Is the universe really expanding ever faster and faster
Laser Guide Star for Large Segmented-Aperture Space Telescopes, Part I: Implications for Terrestrial Exoplanet Detection and Observatory Stability
Precision wavefront control on future segmented-aperture space telescopes
presents significant challenges, particularly in the context of high-contrast
exoplanet direct imaging. We present a new wavefront control architecture that
translates the ground-based artificial guide star concept to space with a laser
source aboard a second spacecraft, formation flying within the telescope
field-of-view. We describe the motivating problem of mirror segment motion and
develop wavefront sensing requirements as a function of guide star magnitude
and segment motion power spectrum. Several sample cases with different values
for transmitter power, pointing jitter, and wavelength are presented to
illustrate the advantages and challenges of having a non-stellar-magnitude
noise limited wavefront sensor for space telescopes. These notional designs
allow increased control authority, potentially relaxing spacecraft stability
requirements by two orders of magnitude, and increasing terrestrial exoplanet
discovery space by allowing high-contrast observations of stars of arbitrary
brightness.Comment: Submitted to A
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