The draft roadmap for technology area (TA) 08, Science Instruments, Observatories, and Sensor Systems, consists of three level 2 technology subareas:1
• 8.1 Remote Sensing Instruments/Sensors
• 8.2 Observatories
• 8.3 In Situ Instruments/Sensors
The TA08 roadmap addresses technologies that are primarily of interest for missions sponsored by NASA’s Science Mission Directorate. They are directly relevant to space research in Earth science, heliophysics, planetary science, and astrophysics; and many areas also have potential applications for the National Oceanic and Atmospheric Administration (NOAA), the Department of Defense (DOD), and commercial remote sensing missions. NASA’s science program technology development priorities are generally driven by science goals and future mission priorities recommended in NRC decadal survey strategy reports, and the panel considered those priorities in evaluating the roadmap’s level 3 technologies (NRC, 2011, 2010, 2007, 2003).
Before prioritizing the level 3 technologies included in TA08, several technologies were added, renamed, deleted, or moved. The changes are explained below and illustrated in Table K.1. The complete, revised technology area breakdown structure (TABS) for all 14 Tas is shown in Appendix B.
8.1.3 Optical Components was merged with 8.2.1. Mirror Systems and renamed: 8.1.3 Optical Systems because the technologies are very similar and it would be most effective to develop these technologies together.
8.1.7 Space Atomic Interferometry has been added to fill a gap in the roadmap. Atomic interference of laser-cooled atoms has enabled fundamental physics laboratory experiments (at technology readiness level (TRL) 4), including gravitational measurements with greatly improved precision. Advances in this technology could lead to extremely sensitive space detectors for acceleration and, thus, gravity waves.
8.2.4 High Contrast Imaging and Spectroscopy Technologies has been added to fill a gap. Development of advanced approaches to high-dynamic-range imaging would be a game-changing technology to support exoplanet imaging, which is a priority initiative in the Astro2010 decadal survey for astronomy and astrophysics (NRC,
1 The draft space technology roadmaps are available at http://www.nasa.gov/offices/oct/strategic_integration/technology_roadmap.html.
TABLE K.1 Technology Area Breakdown Structure for TA08, Science Instruments, Observatories, and Sensor Systems
|NASA Draft Roadmap (Revision 10)||Steering Committee-Recommended Changes|
|TA08 Science Instruments, Observatories and Sensor Systems||Several technologies have been added or merged.|
8.1. Remote Sensing Instruments /Sensors
8.1.1. Detectors and Focal Planes
8.1.3. Optical Components
|Rename: 8.1.3. Optical Systems (now includes substance of 8.2.1)|
|Add: 8.1.7 Space Atomic Interferometry|
8.2.1. Mirror Systems
|Delete: 8.2.1. Mirror Systems (merged into 8.1.3)|
8.2.2. Structures and Antennas
8.2.3. Distributed Aperture
|Add: 8.2.4 High Contrast Imaging and Spectroscopy Technologies|
|Add: 8.2.5 Wireless Spacecraft Technologies|
8.3. In Situ Instruments/Sensors
8.3.1. Particles: Charged and Neutral
8.3.2. Fields and Waves
|Merge 8.3.2 into a renamed 8.3.1, Particles, Fields, and Waves:|
8.3.3. In Situ (Instruments and Sensors)
Charged and Neutral Particles, Magnetic and Electric Fields
|Delete 8.3.2. Fields and Waves (merged into 8.3.1)|
|Add: 8.3.4. Surface Biology and Chemistry Sensors: Sensors to|
Detect and Analyze Biotic and Prebiotic Substances
2010). This technology would provide unprecedented sensitivity, field of view, and spectroscopy of exoplanetary systems, with many subsidiary applications such as solar physics and the study of faint structures around bright objects (such as jets, halos, and winds).
8.2.5 Wireless Spacecraft Technologies has been added to fill a gap in the roadmap. The use of wireless systems in spacecraft avionics and instrumentation will usher in a new and game-changing methodology in the way spacecraft and space missions will be designed and implemented. Wireless avionics could provide numerous improvements over hard-wired architectures, such as inherent cross-strapping, an architecture that is extensible and reliable; reduction in cable mass; and a significant reduction in the cost and time of system integration and test.2
Two technologies in the roadmaps (8.3.1 Particles: Charged and Neutral and 8.3.2 Fields and Waves) seem to have so much overlap that they have been combined to form one entry. The title of the new technology is 8.3.1 Particles, Fields, and Waves: Charged and Neutral Particles, Magnetic and Electric Fields.
TOP TECHNICAL CHALLENGES
The panel identified the following list of six top technical challenges that help provide an organizing framework for setting priorities. Two pertain to crosscutting technologies, and the other four relate to specific important scientific goals. They are listed below in priority order.
1. Rapid Time Scale Development: Enable the exploration of innovative scientific ideas on short time scales by investing in a range of technologies that have been taken to sufficiently high TRLs and that cover a broad class of applications so that they can be utilized on small (e.g., Explorer and Discovery-class) missions.
2Avionics (including wireless avionics) is a crosscutting gap that is not addressed in the draft roadmaps (see Tables 4-1 and 4-2)
Innovative ideas need to be tested and evaluated on a rapid time scale, so that the best of them can be brought to maturity. To accomplish this goal, there needs to be inexpensive and routine access to space for technology demonstration. Continuing cooperative programs for instrument development within university engineering and science departments also can be a key asset. This type of program needs to promote development of appropriate management tools and of engineering parts kits that utilize standard interfaces, which can make instruments significantly easier to integrate and test.
2. Low-Cost, High-Performance Telescopes: Enhance and expand searches for the first stars, galaxies, and black holes, and advance understanding of the fundamental physics of the universe by developing a new generation of lower-cost, higher-performance astronomical telescopes.
Cosmologically important astronomical objects are very distant, producing faint signals at Earth. Measurement requires much larger effective telescope collecting areas and more efficient detector systems, spanning the wavelength range from far infrared into the gamma-ray region. This goal requires new, ultra-stable, normal and grazing incidence mirrors with low mass-to-collecting area ratios. A challenge will be to maintain or extend the angular and spectral resolution properties for such mirror systems, which must be coupled to advanced, large-format, low-noise focal plane arrays. Advanced detector systems will require sub-Kelvin coolers and high-sensitivity camera systems.
3. High-Contrast Imaging and Spectroscopy: Enable discovery of habitable planets, facilitate advances in solar physics, and enable the study of faint structures around bright objects by developing high-contrast imaging and spectroscopic technologies to provide unprecedented sensitivity, field of view, and spectroscopy of faint objects.
Among the highest-priority and highest-visibility goals of the space science program is the search for habitable planets and life upon them; only technologies that are fully developed and demonstrated to a high level will facilitate the large, expensive missions needed to achieve this goal. Such technology, once implemented, will set the stage for detailed study of planetary systems, their formation, nature, evolution, and death. The new capabilities will also be of fundamental value for a wide variety of high-contrast targets such as active galactic nuclei and their relativistic jets and subtle but scientifically important features on the sun.
4. Sample Returns and In Situ Analysis. Determine if synthesis of organic matter may exist today, whether there is evidence that life ever emerged, and whether there are habitats with the necessary conditions to sustain life on other planetary bodies, by developing improved sensors for planetary sample returns and in situ analysis.
The needed technologies include integrated and miniaturized sensor suites, sub-surface sample gathering and handling, unconsolidated-material handling in microgravity, temperature control of frozen samples, portable geochronology, and instrument operations and sample handling in extreme environments. In order to enable missions to surfaces of Venus and outer planet satellites, geological, geophysical, and geochemical sensors and instrumentation that survive in extreme environments will be necessary.
5. Wireless Systems. Enhance effectiveness of spacecraft design, testing, and operations, and reduce spacecraft schedule risk and mass, by incorporating wireless systems technology into spacecraft avionics and instrumentation.
To make wireless systems ready for application in spacecraft, current ground-based network technologies will need to be adapted and improved to accommodate very high data rates, provide high throughput and low latency wireless protocols, support a myriad of avionics interfaces, and be immune to interference.
6. Synthetic Aperture Radar. Enable the active measurement from space of planetary surfaces and of solid-Earth and cryosphere surface deformation and monitoring of natural hazards by developing an affordable, lightweight, deployable synthetic aperture radar antenna.
Synthetic aperture radar can provide unique information having both scientific and beneficial applications value regarding earthquakes, volcanoes, landslides, ground subsidence, floods, glacier surges, and ice sheet/shelf collapse. In addition, synthetic aperture radar can enable measurements of planetary surfaces, such as geologic features on the cloud-shrouded surfaces of Venus or Titan. Major advances can come either via a large single structure or apertures distributed across two or more spacecraft. The technology also will depend on advances in high-performance computing in space.
QFD MATRIX AND NUMERICAL RESULTS FOR TA08
Figures K.1 and K.2 show the relative ranking of each technology. The panel assessed seven of the technologies as high priority. Four of these were selected based on their QFD scores, which significantly exceeded the scores of lower ranked technologies. After careful consideration, the panel also designated three additional technologies as a high-priority technology.3
The TA08 technologies are displayed in Figure K.2 in order of priority.
FIGURE K.1 Quality function deployment (QFD) summary matrix for TA08 Science Instruments, Observatories, and Sensor Systems. The justification for the high-priority designation of all high-priority technologies appears in the section “High-Priority Level 3 Technologies.” H = High Priority; H* = High Priority, QFD score override; M = Medium Priority.
3In recognition that the QFD process could not accurately quantify all of the attributes of a given technology, after the QFD scores were compiled, the panels in some cases designated some technologies as high priority even if their scores were not comparable to the scores of other high-priority technologies. The justification for the high-priority designation of all the high-priority technologies for TA08 appears in section “High-Priority Level 3 Technologies.”
FIGURE K.2 Quality function deployment rankings for TA08 Science Instruments, Observatories, and Sensor Systems.
CHALLENGES VERSUS TECHNOLOGIES
Figure K.3 provides an overview of the linkages between the level 3 technologies and the panel’s list of top technical challenges for space science instruments, observatories, and sensor systems.
HIGH-PRIORITY LEVEL 3 TECHNOLOGIES
Panel 3 identified seven high-priority technologies in TA08. The justification for ranking each of these technologies as a high priority is discussed below.
Technology 8.2.4, High-Contrast Imaging and Spectroscopic Technologies
Development of these technologies would enhance high-dynamic-range imaging and support the 2010 astronomy and astrophysics decadal survey priority initiative for exoplanet imaging. There is a strong linkage between this technology and making progress on the top technical challenge to enable discovery of habitable planets, facilitate advances in solar physics, and enable the study of faint structures around bright objects. Technical approaches identified in the decadal survey include star shades (external occulters), interferometry, and coronagraphy (NRC, 2010). The technical challenges (currently at TRL 3 to 4) are well understood; progress would come from merging of several crosscutting technologies.
This technology is well-aligned with NASA’s expertise, capabilities, and facilities and with its major industrial partners. The primary focus is on direct imaging and spectroscopy of exoplanets in the habitable zone, but the technology is relevant to any application requiring high dynamic range measurements including potential national defense applications. Use of the ISS is not required for this.
This new technology is game-changing because it would provide substantially increased sensitivity, field of view, and spectroscopy of exoplanetary systems, with many subsidiary applications such as solar physics and the study of faint structures around bright objects (jets, halos, winds, etc.). This area received the panel’s highest score due to its high scientific value, relevance to multiple NASA science mission areas, and high ratings for risk and reasonableness.
Technology 8.1.3, Optical Systems
Two optical systems technologies are of particular interest: active wavefront control and grazing-incidence optical systems. There is a strong linkage between these technologies and making progress on the top technical challenge regarding development of a new generation of lower-cost astronomical telescopes.
FIGURE K.3 Level of support that the technologies provide to the top technical challenges for TA08 Science Instruments, Observatories, and Sensor Systems.
Active wavefront control enables the modification of mirror figure and alignment in response to external disturbances. It allows automated on-orbit alignment of optical systems and the use of lightweight mirrors and telescopes. Current state of the art for alignment of individual mirror segments (e.g., James Webb Space Telescope) is TRL 6. Technology for active adjustment of individual mirror segments is TRL 4 to 5. Although ground-based telescopes routinely use wavefront compensation to correct for atmospherically induced disturbances, this approach cannot be applied readily to a space observatory. Because lightweight, actively controlled telescope systems will be challenging to test fully in a 1-g environment, low-cost access to space, possibly including use of the ISS, will open key opportunities for maturing the TRL of the technology.
Active wavefront control aligns closely with NASA’s need to develop the next generation of large-aperture astronomical telescopes, lightweight laser communication systems, and high-performance orbiting observatories for planetary missions. NASA has built capabilities and expertise in this technology by a long history of space-borne electro-optical sensors. There also may be interest and expertise in the DOD for this technology. The challenge in developing reliable techniques will be in demonstrating them in microgravity environments.
As evaluated by the 2010 astronomy and astrophysics decadal survey, the TRL ranges from 2 to 3 for grazing incidence systems and from 2 to 5 for normal-incidence technology. These technologies are well-aligned with NASA’s expertise, capabilities, and facilities and with its major industrial partners. Access to the ISS is not required for work on grazing-incidence mirror systems. Access to the ISS may be helpful as a test bed for development of active wavefront control.
Further development in grazing-incidence optical systems to improve spatial resolution by at least a factor of 10, without increasing mass per unit area, is critical for future x-ray astronomy missions. This will involve improvements in production systems for piezo adjustment of thin slumped glass and in mounting and testing the sets of optics. Applications are for x-ray and far ultraviolet (UV) (<500 Angstrom) astronomy, and may be extended into the soft gamma/hard x-ray region (to ~100 keV). Two-dimensional adjustment capability may also benefit the synchrotron community.
These are game-changing technologies that would enable direct imaging of stars and detailed imaging of energetic objects such as active galactic nuclei. Adjustable optics based on thin, slumped glass, is a game-changing technology. Normal incidence mirrors with diameters of four meters and beyond that could operate to wavelengths as low as 300 angstroms also would be a game-changing technology.
Technology 8.1.1, Detectors and Focal Planes
Development of sub-Kelvin coolers and high-sensitivity detectors (covering three different spectral energy bands: far-infrared (IR), far and extreme UV, and few-keV x-rays) are very-high-priority efforts for future space astronomy missions. There is a strong linkage between these technologies and making progress on the top technical challenge regarding development of a new generation of lower-cost astronomical telescopes. These devices have reached TRL 4-5 in the laboratory, but further work is needed to make the technologies space-qualified. The necessary expertise is well aligned with NASA’s in-house, university, and industry-based capabilities. The DOD also supports work in these areas. Access to the ISS is not required.
This technology is game-changing for the following reasons: The availability of capable sub-K refrigerators could enable long-duration space missions that would be important for many NASA science disciplines including astronomy and planetary studies. Development of these refrigeration technologies could also enable entire new categories of devices that could have enormous commercial and social impact, such as superconducting and quantum computing and superconducting electronics. The proposed technology development would permit 10 times greater sensitivity than current IR satellite observatories for wavelengths above 250 microns and much higher pixel count detectors. Improvement of nearly an order of magnitude in sensitivity and pixel count for FUV and EUV wavelengths would enable new missions, for example to study star formation in galaxies with unprecedented sensitivity and resolution. The proposed improvement in X-ray detectors could significantly decrease the cost and/or increase the capability of next-generation x-ray observatories.
Technology 8.3.3, In Situ Instruments and Sensors
There is a strong linkage between these technologies and making progress on the top technical challenge to determine if synthesis of organic matter may exist today, whether there is evidence that life ever emerged, and whether there are habitats with the necessary conditions to sustain life on other planetary bodies. Geological, geophysical, and geochemical sensors and instrumentation need to be designed that will survive in extreme environments, such as high atmospheric pressure, high or low temperature, and adverse chemistry. Examples of instrument types include cameras and imagers, spectrometers, radiation sensors, seismometers, magnetometers, and entry-descent-landing instruments. The potential benefits of this technology are very high, and in view of the current TRL of 4, the risk of full development to flight is low.
NASA’s role in the development of this technology is crucial for advancing it and tailoring it for specific missions that will investigate the composition of solar-system bodies and their atmospheres and conduct searches for life. Access to the space station is not required.
This new technology is game-changing because it would enable missions to the surface and atmosphere of Venus and the surface and sub-surface of outer planet satellites such as the Jovian and Saturnian moons.
Technology 8.2.5, Wireless Spacecraft Technology
Wireless spacecraft technology was added to the observatories subarea of the original NASA roadmap because the use of wireless systems in spacecraft avionics and instrumentation can usher in a new, game-changing methodology in the way spacecraft and space missions will be designed and implemented. Wireless avionics can provide reliable subsystem-to-subsystem communications that facilitate a new fault-tolerant, inherently cross-strapped, extensible, and reliable architectural approach.
To make wireless systems ready for application in spacecraft, current ground-based network technologies will need to be adapted and improved to:
• Accommodate very high data rates as well as low data rates within and between spacecraft subsystems.
• Provide high-throughput and low-latency wireless protocols.
• Support a myriad of avionics interfaces (serial/parallel interfaces, RS-422, 1553, etc.).
• Be immune to interference, including multi-path self-interference.
Ultimately, these systems will require flight testing and demonstration.
The current TRL is estimated to be 3. Several R&D groups in NASA centers, industry, and academia, are investigating the wireless approach. Simple sensors and devices have been flown on shuttles and the ISS. While access to the ISS is not required, testing of new wireless sensors and systems on the ISS would greatly benefit their development.
The panel overrode the QFD score for this technology to designate it as a high-priority technology because it directly relates to meeting the top technical challenge to enhance effectiveness of spacecraft design, testing, and operations, and reduce spacecraft schedule risk and mass, by incorporating wireless systems architecture into spacecraft avionics and instrumentation.
Wireless avionics will provide reliable subsystem-to-subsystem communications with the following improvements over hard-wired architectures:
• Reduces cable mass,
• Reduces integration and test schedule along with maintenance, upgrade, and turnaround time,
• Allows multiple simultaneous communications between subsystems, improving response,
• Significantly reduces the cost and time of system integration and test,
• Provides inherent electrical isolation between subsystems, and
• Provides redundancy against cable and connector failures: increased spacecraft avionics reliability.
Technology 8.1.5, Lasers
Lasers are fundamental components of topographic lidars, atmospheric composition probes (e.g., for CO2 concentration), and Doppler wind instruments. Key enabling technologies for space are increased laser efficiency and long life. Increased output power, resulting from increased efficiency would enable missions such as multi-beam topographic lidars and high-power, multi-frequency lasers for 3D wind and aerosol and ozone mapping and profiling. A challenge for space is avoiding contamination, which can result in long-term damage where intensity is high— a serious issue for pulsed lasers with high peak power. As noted in the Earth science and applications decadal survey, a “hybrid (combination of two DWL systems, coherent and non-coherent, operating in different wavelength ranges that have distinctly different but complementary measurement advantages and disadvantages). Hybrid Doppler wind lidar (HDWL) in LEO could have a transforming effect on global tropospheric-wind analyses” (NRC, 2007, p. 138).
The panel overrode the QFD score for this technology to designate it as a high-priority technology because the QFD scores did not capture its applications value— a NASA laser demonstration mission to obtain Earth’s 3-D wind field would define Earth’s atmospheric momentum field with unprecedented quality and add to numerical weather prediction capabilities, especially for severe storms.
The laser industry is a multi-billion dollar enterprise characterized by strong innovation over a broad technical area. It is clear that NASA investment, only if focused by the above specific mission needs, can make a significant contribution to the industry as a whole. Laser developments would also have high potential payoff for future chemical-weather and air-pollution applications. The panel concurs with the decadal survey statement that recommended “an aggressive program to design, build, aircraft-test, and ultimately conduct space-based flight tests of a prototype HDWL” (NRC, 2007, p. 138). NASA would be well served by evaluating and encouraging emerging laser technologies as needed to support the ongoing needs of space missions identified in decadal survey reports and by focusing on approaches for qualifying laser systems for space. In doing so, NASA technology development can respond to the needs of the science community, serve society, and bring later-tier decadal missions that depend on this technology maturation closer to hand.
Technology 8.1.2, Electronics
The state of the art in readout circuitry supports detector sizes currently in flight use (~4 k x 4 k pixels). The design of future readout integrated circuitry (ROIC) to support larger detector sizes will require appropriate design, layout, simulation tools, and fabrication, making use of state-of-the-art ASIC technology. Note that among the attributes of speed, power noise, and capacity (as in number of pixels, channels, etc. read) not all are needed for every detector application. This technology is directly aligned with NASA’s expertise, capabilities, facilities, and role in development, and is directly in concert with the thrust toward large detectors and arrays. Access to the ISS is not required to support development in this technology.
The panel overrode the QFD score for this technology to designate it as a high-priority technology because the QFD scores did not capture the value of this technology in terms of its broad applicability to many categories of NASA missions, commercial imaging, NOAA missions, and the national security space communities. There is a strong linkage between these technologies and making progress on the top technical challenge regarding development and maturation of technologies for small missions in short time scales, and the technologies will be valuable in facilitating progress in all of the top technical challenges. Future instruments using large arrays of many types, such as charge-coupled devices (CCDs), photon detectors, or spectrometers, will require new ROIC to fully realize the performance gains from these arrays. High-density, high-speed, low-noise, and low-power ROIC will enable instruments of reduced power and mass, reduced parts count, and simpler designs, with commensurate increased reliability. Instruments intended for extreme environments (high radiation or low temperature) will also benefit from radiation hardening or low temperature capability.
TA08 includes 10 level 3 technologies that were ranked at medium priority. As a group, these technologies generally had lower benefit and/or alignment scores than the high-priority technologies. As noted above, three of these technologies were elevated to high priority, and so they have been discussed above.
A new level 3 technology for space atomic interferometry (8.1.7) was added because atomic interference of laser-cooled atoms has enabled fundamental physics laboratory experiments (at TRL 4) including gravitational measurements of greatly improved precision, and this technology could potentially lead to extremely sensitive space detectors of acceleration and thus of gravity waves.
A new level 3 technology for surface biology and chemistry sensors (8.3.2) was added because low-mass, low-power, and small-volume envelope technologies for ultra-high-resolution mass spectrometry and automated microchip electrophoresis will allow highly sensitive analyses of organic compounds everywhere in the solar system, including Mars, Europa, Titan, and small bodies. This technology received the highest medium-priority score because of its high scientific value and potential alignment with users outside NASA.
Two medium-priority technologies— 8.3.2 Surface Biology and Chemistry Sensors and 8.2.3 Distributed Aperture—were considered to be potentially game changing, but their scores fell below the panel’s high-priority cutoff. This illustrates the fact that defining a set of realistic and affordable priorities required the panel to make some difficult choices, and it does not reflect a view that these two technologies are unimportant. The other medium-priority technologies all tended to lack identified users or missions or to have only niche roles. Particles, fields, and waves sensor technologies were assigned the lowest medium-priority ranking because, while they are aligned with NASA heliophysics mission areas, they have limited linkage to other aerospace or non-aerospace applications and because they need only incremental improvements.
PUBLIC WORKSHOP SUMMARY
The Instruments and Computing Panel (Panel 3) for the NASA Technology Roadmaps study held a workshop on Science Instruments, Observatories, and Sensor Systems (NASA Technology Roadmap TA08) on March 29, 2011, at the National Academies Beckman Center in Irvine, California. The workshop was attended by members of Panel 3, one or more members of the Steering Committee for the NASA Technology Roadmaps study, invited workshop participants, study staff, and members of the public who attended the open sessions. The workshop began with a short introduction by Jim Burch, the panel chair, in which he emphasized the need for inputs from the scientific community. What followed was a series of six hour-long panel discussions, then a 45-minute session for public comment and general discussion, and finally a short summary and wrap-up by the panel chair. Each panel discussion was moderated by a Panel 3 member. Experts from industry, academia, and/or government were invited to present.
Panel Discussion 1: Technology Tests and Demonstrations
via Suborbital and Low-Cost Orbital Flight
The first session focused on the crosscutting issue of using low-cost suborbital and orbital flights to advance in-space technologies. The session was moderated by Webster Cash.
The first presentation was given by Christopher Martin (California Institute of Technology), chair of the Astrophysics Sounding Rocket Assessment Team (ASRAT). He emphasized the importance of sounding rockets as a platform to develop technology for future missions and provided a summary of their historical success in doing so. He also noted that they have been used to train the next generation of space experimentalists and technologists by providing an end-to-end experience in carrying out a space science mission. ASRAT recommends that NASA initiate an Orbital Sounding Rocket (OSR) program to launch science payloads of up to 1,000 lb. into low Earth orbit with mission durations from 1 to 100 days, at a rate of at least one launch per year. They believe that an OSR program would allow for additional tests and science that could not be done using current short suborbital flights. An OSR program would fill the gap between suborbital flights that cost a few million dollars and orbital missions
that start at around $100 million. ASRAT believes that OSR would be a game-changing platform for technology innovation, workforce development, and science for NASA and other government agencies.
Alan Stern (Southwest Research Institute) discussed the use of emerging commercial reusable suborbital vehicles to fly experiments. These systems may provide three to four minutes of microgravity (10 times the microgravity time of zero-gravity aircraft and a 100 times cleaner microgravity environment) at 140 km altitude, enabling additional applications that are not possible on other platforms. The human suborbital tourism market may lead to routine flights and low costs. It could allow flying off-the-shelf laboratory equipment with researchers along (since these vehicles would be human-rated for tourism) at a tenth the cost of sounding rockets. Many of the commercial companies have proposed payload bays that would be exposed to the flight environment. Stern said that it will likely be a challenge to NASA to accept these new systems, but they will eventually change the way NASA can develop new systems.
Ray Cruddace (Naval Research Laboratory) discussed routine low-cost access to space (RLCAS). The objectives are to make science observations quickly in order to test new scientific ideas and predictions, to subject new instruments to flight testing, and to expand the envelope for scientific research and technology development beyond the 5 to 10 minutes provided by suborbital sounding rockets. RLCAS is envisioned as developing from the current sounding rocket program into an OSR. The essence of an OSR program is to accept a certain level of risk, maintain an experienced engineering team, use off-the-shelf components, conduct thorough environmental testing, and use a proven launch vehicle. The most promising current candidate launch vehicle is the Falcon 1e at a cost of $10.5 million in fiscal year 2009. The envisioned characteristics of an OSR mission in general include a mission duration of 1 to 3 months, a launch frequency of at least once per year, and a mission cost target of $30 million. The potential user community includes NASA, DOD, and universities.
Panel Discussion 2: Observatories
The next session focused on next generation space-based observatories as a whole. The session was moderated by John Hackwell.
Jim Anderson (Harvard) focused his presentation on observatories needed to study climate change. He discussed the impact on national priorities—especially the link between global energy demand and climate. For the trillion dollar industry associated with global energy demand, the time to adjust is decades. For climate, the time-scale is years, and there are questions of feedback and irreversibility. He suggested that climate feedback loops such as those influencing arctic sea ice should drive technology decisions. He also discussed the ability to perform some of these observations using both robotic aerial platforms and small spacecraft.
Tony Hull (L-3 Integrated Optical Systems) discussed programmatic issues that have plagued NASA technology development efforts. His experience with the Terrestrial Planet Finder project has shown him the importance of stable and continuous technology development efforts with thorough plans. He stated that there needs to be early selection and stabilization of a consensus minimal science requirement, definition of an associated realistic budget, and a convergent process for stabilization of a baseline technical approach with redundant capabilities. He expressed concerns about the health of the U.S. industrial base and the repercussions of dwindling development budgets. He also noted the potential impact of International Traffic in Arms Regulations (ITAR) in effect restricting of multi-national organizations from partnering with NASA. The net result is that offshore space technologies are surpassing U.S. technological capabilities. In reference to specific technology priorities, he suggested that wavefront control via active mirrors should have an increasing role as systems get larger and less rigid, but actuated mechanisms are an anathema for managers of many space observatory programs. He believes that adaptive mirrors that use wavefront sensing and control is a game-changing technology for large aperture systems. He sees optical substrate fabrication (to reduce mirror mass) and optical finishing techniques as near a tipping point that might result in a breakthrough for mass and performance.
Panel Discussion 3: Photon Detectors (IR, Visible, UV)
The next session focused on photon detectors for the visible and near visible regions of the electrodynamic spectrum and was moderated by Joel Primack.
Terry Lomheim (The Aerospace Corporation) gave a presentation that focused on focal plane arrays. He began his talk by pointing out the differences between commercial terrestrial needs and in-space applications while explaining why in-space arrays are so much more expensive. In-space array requirements lead to fewer arrays per silicon wafer and less wafers per design. He believes that this leads to a key challenge of keeping the fabrication/manufacturing supply chain going. He also discussed his views of the technology challenges by emphasizing the need for even larger complementary metal oxide semiconductor (CMOS) arrays and their corresponding readout integrated circuits (ROICs). He believes that all interested organizations (including NASA and other government organizations) would have to have major coordinated development efforts to push the technology forward.
Christopher Martin (California Institute of Technology) discussed the potential impacts of UV/optical photon-counting detector technology developments. He said that current state-of-the-art detectors have a quantum efficiency of around 10 percent, which is far below the theoretical limit, and development has hit a wall within the cost scope. He believes that photon-counting detectors will vastly improve spectral, spatial, and temporal resolution, higher pixel count, and provide high dynamic range. These advances are required for several future science missions and could provide the potential for large cost savings of others. One example is Cosmic Web Baryon Mapping, which looked at three different technologies to reach a given signal-to-noise-ratio and photon counting required the smallest telescope diameter and the least money. He noted one specific promising technology of back-illuminated, delta-doped, AR-coated electron multiplying CCDs that are reaching up to 50 percent quantum efficiency with a TRL of 4-5.
Oswald Siegmund (University of California, Berkeley) gave the final presentation which focused on microchannel plate (MCP) photon counting detectors. He said that MCPs have been involved in many NASA and ESA ultraviolet space-based missions and continue to be proposed and selected for future missions. Siegmund described some of the current MCP detector developments at Berkeley including increasing the size, improvements in photocathode quantum efficiency (QE) to >50 percent, and improving the operability and cost. He noted that the supporting electronics need to be improved to achieve the full performance benefits of these detector advances. He noted one particular technology, Borosilicate Glass MCPs, with large areas could be a game changer, but this technology is still at an early stage.
Panel Discussion 4: Photon Detectors (X-Ray, Gamma-Ray)
The next session focused on photon detectors for the higher energy region of the electrodynamic spectrum and was moderated by Alan Title.
Steve Murray (Johns Hopkins University) gave the first presentation on x-ray detectors needed for future missions. He said that current envisioned missions have identified very specific technical needs. For instance, the International X-ray Observatory wants 1,024 elements, while the current state-of-the-art is tens of elements. He believes that current CCD technology is pushing up against limits of improving the number of pixels and speed. Some of the approaches he mentioned to meet the needs of next generation observatories include a mosaic of many smaller arrays and ASICs for low power processing. He said that CMOS technology is newer and a potentially game-changing technology where it may be possible to event trigger at the pixel. However, current x-ray CMOS production is very unreliable.
Kent Irwin (National Institute of Standards and Technology) gave the second presentation. He started by saying that from a technology perspective, low-temperature detectors (LTD) used in x-ray applications have enormous leverage/coupling to those used at longer wavelengths and their investments should be considered together. He believes that single pixel LTDs are almost as good as they need to be and can be in terms of energy resolution (both long wavelength and x-ray). He thinks that most of the technology advancements will come with increasing array size with the current size of LTD arrays doubling about every 20 months. The state of the art for sub-millimeter LTD is 10,000 pixels and 256 for x-ray. He said that the supporting electronics is the area with the greatest potential
for cost improvements. As arrays increase in size there is a need for improved techniques to modulate and encode the detector signals.
Panel Discussion 5: Earth and Planetary Remote Sensing Observation
The session covering remote sensing of Earth and other planetary bodies within the solar system was moderated by David Kusnierkiewicz.
Chris Webster (Jet Propulsion Laboratory) and Keith Raney (Applied Physics Laboratory) jointly gave the presentation, which was a broad survey of Earth and planetary remote sensing instruments and sensors. The presentation began with a summary of the challenges inherent in remote planetary missions including developing for mission-unique environments. They showed examples of typical payload suites of Earth and planetary science spacecraft to emphasize the diversity of the instruments carried. They also cataloged the current and proposed NASA Earth and Planetary science missions.
The presentation gave a summary review of the NASA roadmap with focus on the Remote Sensing Instruments/Sensors technology area. They noted potential gaps such as the possibility of including high-bandwidth downlink under Electronics (8.1.2). They also noted that innovative architectures (as opposed to specific technology elements) might be missing using the Lunar Reconnaissance Orbiter mission as an example of a paradigm shift that occurred under 8.1.4 Microwave and Radio Transmitters and Receivers. They also suggested more discussion of the impacts of enabling technologies from other roadmaps using examples of improved communications and reduced launch costs. They believe that NASA should strive to identify technology push factors for every one of the 11 pathways (in 6 themes) in the TA08 roadmap. Finally, they suggested that Tier 1 missions not now in NASA’s funding plan should also be considered in regard to new technologies.
The presenters then gave their views on the direction that NASA should take with technology development. They emphasized the comment in the roadmap that a healthy technology R&D program requires three elements: competition, funding, and peer review. They noted that the recent Planetary Decadal Survey suggested that 6 to 8 percent of the total NASA Planetary Science Division budget should be dedicated to technology development and that resource allocation should be carefully protected. They noted that affordability is a fundamental factor given the recent descopes suggested by the Planetary Decadal Survey and NASA’s Earth Science budget proposal.
Panel Discussion 6: In Situ Surface Physical, Chemical, and Biological Sensors
The final session covered interactive measurements of non-Earth bodies within the solar system and was moderated by Daniel Winterhalter (JPL).
Jeffrey Bada (University of California, San Diego) was the first presenter and he focused on the challenge of detecting organic and biological matter. He noted that on Earth, a pre-biotic phase led to a pre-RNA world, which led to an RNA world. The RNA world would have been considered an early stage of life on Earth. That led to a DNA/protein world that is the basis for all terrestrial biology. All of this was assumed to take place in liquid water which is considered the most abundant solvent in the universe. Bada suggested that the search for weird life based on some other biochemistry or solvent should not be included because we do not know what to look for. Instead he suggested that future missions follow the nitrogen. He noted that in carbonaceous meteorites as well as in prebiotic simulation synthesis experiments, there are at least 50 to 70 different amino acids, while in biology as we know it there are only 20 different amino acids in proteins. He suggested that a simple total amine detector the size of a box of stick matches would be a good initial instrument. He believes that a Mars organic analyzer the size of a shoebox is the next step as it can address the issue of homochirality, which is a unique characteristic of amino acids on Earth and presumably life elsewhere as well.
Michael Hecht (Jet Propulsion Laboratory) gave the second presentation, which began with a quick review of the in situ instrument roadmap. He noted some sensor challenges that were not in the roadmap include in situ geochronology and ultra-high-resolution mass spectroscopy (resolve isobars). He felt there were also system challenges not covered in the roadmap including the need to avoid alteration in Mars sample return curation (in situ); extreme environments (Venus, Titan); kW and mW power sources; non-solar, non-nuclear power sources (e.g.,
wind, thermal, chemical); and full spacecraft sterilization for planetary protection and contamination control. He identified non-biological high-priority sensor technology areas as liquid phase analysis (wet chemistry, lab-on-a-chip, and ice/water analysis); mass spectroscopy (isobar-resolving with >100 K resolving power, laser ablation mass spectroscopy, and geochronology); and chemical microscopy (scanning electron microscope/energy dispersive X-ray microanalysis, small spot scanning x-ray fluorescence, spectroscopic imaging, and chromophormicroscopy). He also identified game-changing technologies near the tipping point, including the ability to do things related to sample return (e.g., in situ geochronology, advanced life detection, and micro-analysis). He also identified a broadened access to deep space (flying instruments as discussed earlier in the day) as game-changing.
Public Comment Session and General Discussion
The day concluded with a public comment session moderated by Robert Hanisch. Most of the questions and comments focused on general issues of technology development. Topics included the challenges of maintaining a qualified workforce capable of advancing the state of the art and the difficulties of maintaining the knowledge and capabilities that have already been developed.
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