Enabling Technologies for Next Generation Ultraviolet Astrophysics, Planetary, and Heliophysics Missions
Creators: name: Martin, D. Christopher
name: Nikzad, Shouleh
name: Schiminovich, David
Publisher: name: Keck Institute for Space Studies
Year: 2012

description: Our study sought to create a new paradigm in UV instrument design, detector technology, and
optics that will form the technological foundation for a new generation of ultraviolet missions.
This study brought together scientists and technologists representing the broad community of
astrophysicists, planetary and heliophysics physicists, and technologists working in the UV.
Next generation UV missions require major advances in UV instrument design, optics and
detector technology. UV offers one of the few remaining areas of the electromagnetic spectrum
where this is possible, by combining improvements in detector quantum efficiency (5-10x),
optical coatings and higher-performance wide-field spectrometers (5-10x), and increasing
multiplex advantage (100-1000x).
At the same time, budgets for future missions are tightly constrained. Attention has begun to turn
to small and moderate class missions to provide new observational capabilities on timescales that
maintain scientific vitality. Developments in UV technology offer a comparatively unique
opportunity to conceive of small (Explorer) and moderate (Probe, Discovery, New Millennium)
class missions that offer breakthrough science.
Our study began with the science,
reviewing the breakthrough science
questions that compel the development of
new observational capabilities in the next
10-20 years. We invented a framework for
highlighting the objectives of UV
measurement capabilities: following the
history of baryons from the intergalactic
medium to stars and planets. In
astrophysics, next generation space UV missions will detect and map faint emission and
tomographically map absorption from intergalactic medium baryons that delineate the structure
of the Universe, map the circum-galactic medium that is the reservoir of galaxy-building gas,
map the warm-hot ISM of our Galaxy, explore star-formation within the Local group and beyond,
trace gas in proto-planetary disks and extended atmospheres of exoplanets, and record the
transient UV universe. Solar system planetary atmospheric physics and chemistry, aurorae,
surface composition and magnetospheric environments and interactions will be revealed using
UV spectroscopy. UV spectroscopy may even detect life on an exoplanet.
Our study concluded that with UV technology developments within reach over the next 5-
10 years, we can conceive moderate-class missions that will answer many of the compelling
science questions driving the field.
We reviewed the science measurement requirements for these pioneering new areas and
corresponding technology requirements. We reviewed and evaluated the emerging technologies,
and developed a figure of merit based on potential science impact, state of readiness, required
investment, and potential for highly leveraged progress in a 5-10 year horizon. From this we
were able to develop a strategy for technology development. Some of this technology
development will be subject to funding calls from federal agencies. A subset form a portfolio of
highly promising technologies that are ideal for funding from a KISS Development Program.
One of our study’s principal conclusions was that UV detector performance drives every aspect
of the scientific capability of future missions, and that two highly flexible detector technologies
were at the tipping point for major breakthroughs. These are Gen-2 borosilicate Atomic Layer
Deposition (ALD) coated microchannel plate detectors with GaN photocathodes, and ALDantireflection
(AR) coated, delta-doped photon-counting CCD detectors. Both offer the potential
for QE&gt;50% combined with large formats and pixel counts, low background, and sky-limited
photon-counting performance over the 100-300 nm band. Ramped AR coatings for
spectroscopic detectors could achieve QE’s as high as 80%!
A second conclusion was that UV coatings are on the threshold of a major breakthrough. UV
coatings permeate every aspect of telescope and instrument design. Efficient, robust, ultra-thin
and highly uniform reflective coatings applied with Atomic Layer Deposition (ALD) offer the
possibility of high-performance, wide-field, highly-multiplexed UV spectrometers and a broadband
reach covering the scientifically critical 100-120 nm range (home of 50% of all atomic and
molecular resonance lines). Our study concluded that UV coating advances made possible by
ALD is the principle technology advance that will enable a joint UV-optical general
astrophysics and exoEarth imaging flagship mission.
A third conclusion was that the revolution in micro- and nano-fabrication technology offers a
cornucopia of new possibilities for revolutionary UV technology developments in the near future.
An immediate example is the application of new microlithography techniques to patterning UV
diffraction gratings that are highly efficient and designed to enable wide-field, high-resolution
spectroscopy. These techniques could support the development of new detectors that could
discriminate optical and UV photons and potentially energy-resolving detection.
Relatively modest investments in technology development over the next 5-10 years could
provide advances in detectors, coatings, diffractive elements, and filters that would result
in an effective increase in science capability of 100-1000!
The study brought together a diverse community, led to many new ideas and collaborations, and
brought cohesion and common purpose to UV practitioners. This will have a lasting and positive
impact on the future of our field.