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Enabling Technologies for the Next Generation of UV-Optical Missions

James C. Green University of Colorado


Technology and Missions: Chicken or Egg ?
What drives the selection of the next mission: science drivers or technical capability? Science question mission concept technical requirements technology funding (NGST/TPF) New technological development new astronomical capability new mission to utilize capability (FUSE)


Only Large Missions Can Afford the First Approach
Explorers, discovery, etc. missions wait for available technology and then propose the best possible science with them. Typically, they address questions that have been around for a while. Giga-missions ( + $1B) should start with the question (TPF) NASA needs both kinds


Examples:
Copernicus FUSE
· (coatings, detectors) · local astronomy galactic astronomy · next generation extragalactic FUV

IUE GHRS STIS COS COBE MAP


Generic UV - 0ptical Technology Drivers
Optics:
· · · · · size with high figure quality size w/o high figure quality ultra-low scatter efficient wide field designs better dispersive optics (aberration control/scatter/efficiency) · new transmitting materials


UV - 0ptical Technology Drivers
Detectors
· · · · · · larger format long-life / slow space degradation lower background higher efficiency energy resolving higher dynamic range


Example Science Goals for the Next Generation of non-G$ UV/optical missions
The baryon census in the modern universe D/H as a function of z The dynamics and recycling of the interstellar medium The proto-extra-solar system environment NONE OF THESE WILL SELL AN HST CLASS MISSION


Where we have been:
As a community we have proposed to build the best possible successor to HST: the largest possible mirror, best possible detectors, greatest field of view and most sensitive spectroscopy - we have then enumerated the many science objectives that can be achieved with such an instrument: all true This has not produced a viable NHST, and will not in the current environment.


Where we need to go:
1: Develop of community consensus on the over-arching scientific objective of a single, great observatory 2: This need not, in fact, should not be a technically viable mission with today's technology 3: Get this scientific vision into the strategic plan, and a mission concept identified with it


Where we need to go: (II)
4: Identify the technology drivers needed, including spacecraft, electronics, propulsion, etc. 5: As these technologies develop, spin-off concepts for SMEX, MIDEX or smaller class missions will spontaneously arise from the community 6: When built, the NHST will of course, do much more than the over-arching goal


An example
The Ultimate Sky Survey
· Deeper than ever, with greater spatial resolution than ever - catalog the universe

Technology Drivers:
· · · · Huge format detectors Ultra low noise, radiation tolerant detectors "UVB" class energy resolution operate out of the ecliptic to control zodiacal light (nuclear) · process and telemeter vast amounts of data


Potential Spin-offs
Ultra-large detector formats:
· Type Ia SN searches · Microlensing searches

Nuclear power and propulsion
· planetary missions · in situ ISM measurement Energy resolution · simultaneous color photometry of time variable events - reverberation mapping


Conclusions: What can NASA do?
Fund enabling technology from both directions. Do not require that technology directly support an identified mission in the strategic plan. For non-mission specific research - keep all areas moving forward: detectors, optics, structures, mission implementation


Conclusions:What can the UVoptical community do?
1: Develop a vision for NHST that has a "killer-ap" and push it single-mindedly. 2: Choose a truly ambitious goal. 3: Stop worrying how an approved NHST might weaken support for your pet program. 4: Do this soon.