Assessment of Options for Extending the Life of the Hubble Space Telescope Final Report (2005) / Chapter Skim
Currently Skimming:
3 The Impact of Hubble: Past and Future
3 The Impact of Hubble: Past and Future
Pages 16-39
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 16... ...
The Hubble telescope provides four key advantages over most other optical astronomical facilities: unprecedented angular resolution over a large field, spectral coverage from the near infrared to the far ultraviolet, an extremely dark sky, and highly stable images that enable precision photometry. Hubble's imaging fields of view are also considerable, permitting mapping of extended objects and significant regions of sky.
|
From page 17... ...
FIGURE 3.2 Two Hubble Space Telescope images illustrate the value of observing at different wavelengths. (left)
|
From page 18... ...
To fill these important gaps, Hubble must work synergistically with other telescopes to complete the portraits of celestial objects at all wavelengths. FINDING: The Hubble Space Telescope is a uniquely powerful observing platform in terms of its high angular optical resolution, broad wavelength coverage from the ultraviolet to the near infrared, low sky background, stable images, exquisite precision in flux determination, and significant field of view.
|
From page 19... ...
for university grant programs and fellowships in all disciplines and wavelengths in the Astronomical Sciences Division at the National Science Foundation. SCIENCE HIGHLIGHTS The Space Telescope Science Institute has studied the scientific impact of Hubble observations using two metrics: the number of citations in the professional astronomical literature and references to Hubble discoveries in the popular media.
|
From page 20... ...
Studies of extrasolar planets Offers a sensitive method for finding planets around other stars, based on partial eclipses when a planet passes in front of a distant star. xxx Giant Black Holes at the Centers of Galaxies Hubble's high angular resolution allows astronomers to peer into the hearts of galaxies to measure the orbital speeds of gas and stars close to their centers.
|
From page 21... ...
of the beginning of our universe. Distant galaxies are seen as progressively smaller and dimmer compared with nearby galaxies.
|
From page 22... ...
Images courtesy of STScI/NASA. Protoplanetary Disks -- Planetary Systems in Formation Many luminous nebulas are dense regions of interstellar gas lit up by ultraviolet radiation from newly born massive stars.
|
From page 23... ...
Intense public interest in Hubble is borne out by many media studies of its impact; an example of the results of such an assessment is shown in Figure 3.7. Having garnered sustained public attention over its entire lifetime, the Hubble Space Telescope is clearly one of NASA's most noticed science projects.
|
From page 24... ...
M2-9 planetary nebula, (5) gravitational lens arcs in the Abell 2218 galaxy cluster, (6)
|
From page 25... ...
FINDING: Astronomical discoveries with Hubble from the solar system to the edge of the universe are among the most significant intellectual achievements of the space science program. SCIENCE IMPACT OF HUBBLE SERVICING MISSIONS Hubble today is not the same telescope that was launched in 1990.
|
From page 26... ...
and the Cosmic Origins Spectrograph (COS) in a fifth servicing mission, SM-4.
|
From page 27... ...
FINDING: The growth in the scientific power of Hubble would continue with the installation of the two new instruments, WFC3 and COS, planned for the SM-4 shuttle astronaut mission. DETERIORATING CAPABILITIES THAT AFFECT HUBBLE'S SCIENCE PERFORMANCE Several Hubble subsystems have limited life and were to be serviced on SM-4.
|
From page 28... ...
The second option would be to devise a way to observe some targets with only one FGS; currently this option would cause a degradation of image quality, but workarounds are under study to reduce image smear by using either an idle science detector or a fixed head star tracker as a substitute FGS. These studies have not progressed very far to date, and success is not assured.
|
From page 29... ...
These are the Aft Shroud Cooling System and the New Outer Blanket Layer, an outer insulation layer. Both of these are included in the shuttle version of SM-4 but not in the baseline robotic mission.
|
From page 30... ...
Finally, Hubble can take exceptionally accurate spectra of planetary systems during eclipse, yielding measurements of water and other species in jovian-sized planetary atmospheres.3 Photometry with the James Webb Space Telescope (JWST) will also have higher accuracy than that possible from ground-based telescopes and will also play an important role in planet detection.
|
From page 31... ...
In this manner, several hundred thousand stars can be searched for Jupiter-size and smaller planets in roughly 1 week of Hubble Space Telescope observing time. Courtesy of STScI/NASA.
|
From page 32... ...
These programs are extremely important because there are no plans in the foreseeable future to replace Hubble with a telescope of comparable size and wavelength coverage. The servicing mission SM-4 is needed to allow an orderly completion of this important aspect of Hubble's mission.
|
From page 33... ...
WFC3's greater UV sensitivity will allow it to discover UV dropouts nearly 10 times fainter than those currently known, deepening our knowledge of distant galaxies beyond the brightest ones currently known. The other gap in instrumentation in the ultraviolet -- spectroscopy -- will be significantly filled by the Cosmic Origins Spectrograph.
|
From page 34... ...
The much higher efficiency of the Cosmic Origins Spectrograph would enable it to take spectra of many more background quasars, creating a dense network of sight lines with which to probe the cosmic web. clues to cosmogenesis.
|
From page 35... ...
Allowing for the overwhelming likelihood of important unforeseen discoveries in addition to those listed in Table 3.4, the committee concludes that the promise for future Hubble discoveries following a servicing mission is comparable to the telescope's promise when first launched. The programs listed in Table 3.4 are also very well aligned with the list of key problems highlighted by the most recent decadal survey report for astronomy and astrophysics, Astronomy and Astrophysics in the New Millennium.4 COMPARISON OF HUBBLE WITH OTHER PLANNED FACILITIES The unique advantage of HST with respect to other astronomical tools is its exquisite angular resolution extending from the ultraviolet to the near infrared.
|
From page 36... ...
Evolution of dark energy WFC3, ACS Understanding the fundamental nature of dark energy. The cosmic web COS Mapping the total distribution of matter in the universe.
|
From page 37... ...
JWST offers exciting capabilities in the near infrared, but JWST has significant development risk and no plans for on-orbit repair. The committee believes that it makes sense to exploit Hubble's proven capabilities for a further 4 to 5 years with one more servicing mission.
|
From page 38... ...
First, the detector in the workhorse ACS camera is steadily accumulating radiation damage, with significantly degraded performance expected around 2010. Second, gyroscope failure is expected to place the Hubble telescope in a one-gyro mode near fall 2007 (see Chapter 4)
|
From page 39... ...
Moreover, all options for rehosting take time to evaluate, select, and develop, and all options carry the risk that a new spacecraft may ultimately fail to operate to specifications. By contrast, Hubble is a proven platform on orbit now, to which several successful servicing missions have already been sent.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.