EEE Links interviewed Dr. Hasso Niemann, Head of the Atmospheric Experiment Branch (Code 915) at NASA Goddard Space Flight Center, to provide system and mission level views of extreme environment electronics and to speculate on future missions with regard to extreme environment issues. This perspective complements the extreme environment parts and packaging applications and reliability issues focus set forth in this issue from our EEE Links authors. Dr. Niemann received his Ph.D. in Electrical Engineering from the University of Michigan in 1969 and has been with Goddard since then. He is renowned worldwide as the authority on developing atmospheric composition measurement techniques using space flight mass spectrometry. The Galileo Probe Mass Spectrometer is the latest in a number of outstanding achievements by Dr. Niemann in his distinguished career; he ensured that the design and construction of the probe’s mass spectrometer could accommodate Jupiter’s strenuous environment, and he won the 1997 John C. Lindsay Memorial Award for his role as Principal Investigator in this work.

EEE Links: What do you foresee for the future of NASA missions to such planets as Venus, Mars, and beyond?

Dr. Niemann: Devices designed to operate in extreme environments are in high demand within NASA’s planetary activities. NASA is currently conducting extreme environment workshops at JPL on in-situ instruments involving spectrometry to measure chemical compositions of atmosphere and soil. Because of the in-situ character, most instruments in planetary research must be able to withstand very hot and cold environments.

The National Research Council has recently released the Solar System Exploration Decadal Survey, “New Frontiers in the Solar System: An Integrated Exploration Strategy.” It reviews the current state of planetary science and exploration and makes recommendations for ground-based and space flight research for the years 2003 to 2013. Key recommendations include maintenance of the Discovery program (low cost, one every 18 months, plus extending the Cassini mission), beginning a New Frontiers line of missions (medium cost, one every 3 years, such as KBO/Pluto Explorer, Lunar South Polar Aitken Basin Sample Return, Jupiter Polar Orbiter with Probes, Venus In-Situ Explorer, and Comet Surface Sample Return), and one large-cost mission (Europa Geophysical Explorer), as well as recommendations for the Mars Explorer Program. The full report can be accessed at http://www.nationalacademies.org/ssb/.

EEE Links: What are the most significant challenges regarding extreme environment in these missions?

Dr. Niemann: Major environmental challenges are temperature, pressure, chemical reactions in the atmospheres (e.g., Venus), and of course radiation. Areas of interest include Venus’ surface and atmosphere; this planet is similar to Earth in some ways, but its atmosphere is dense—there is as much as 100 times more pressure on Venus than on Earth—and it has a hostile high temperature atmosphere of 500 °C with traces of corrosive sulfuric acid. We need to revisit this atmosphere and take more measurements; the challenge posed here is that we need our instruments to survive operation at 500 °C. The electronic devices we have used could survive the environment only for a short time before they were destroyed. To make more detailed measurements, we need extended survival time for the instruments, and that requires greater temperature tolerance. This problem is being worked on; NASA Glenn Research Center is well known for their research in high temperature electronics.

EEE Links: To accomplish these missions, what new materials, technologies, and approaches would be necessary?

Dr. Niemann: High temperature and low temperature electronics, as well as other areas like micro-electromechanical systems, are key technologies that need to be advanced. Certain MEMS technology is especially important because those devices are small and well suited for high temperature environments. Nanotechnology may also play an important role in the future; currently it is being developed primarily in biological areas using biotransistors and so on that are not easy to use in extreme environments, but they could be packaged to avoid temperature effects. We don’t know enough now about the reliability of nanotechnology so it is not on the immediate agenda.

In future Mars missions, we will use drilling techniques to get surface soil samples, as the interesting matter (water, or even life) is most likely to be under the surface. Another approach is sample return, in which an instrument or spacecraft collects samples and brings them back to Earth for very detailed analysis.

In the semiconductor area, high temperature materials such as gallium nitride and silicon carbide are needed that can withstand high temperature environments. In the mechanical area, titanium and possibly carbon fiber materials technology needs to be developed, and efficient cooling techniques that can cool or shield critical components by surrounding them. If the instrument’s lifetime is expected to be short, shielding it to prevent it from reaching the high temperature and pressure of the environment becomes most important. Miniaturization is key in this, as small instrument devices can be shielded more effectively.

The other extreme is cold temperature applications for outer planets, which include Saturn, Jupiter, and their moons; for these we need small, low temperature electronic devices. The atmosphere of Saturn’s moon Titan is not much different from ours on Earth, which makes it important for study, except for that it has 1.5 times Earth’s surface pressure and is 90 °K to 100 °K. We don’t know yet what the surface is made of, but it is probably covered with hydrocarbon and frozen methane/ethane, so we would need low temperature electronics to explore that surface.

EEE Links: What sort of sensor/detector requirements and operational temperature ranges are relevant to these missions?

Dr. Niemann: The most significant requirement is for sensors to be effective where the environment is different from the state in which the measurements can be made; for example, on Venus, the instrument that makes the measurements is operating at a pressure many orders of magnitude below that of the ambient surface pressure. To reduce the sampling pressure for a mass spectrometer, by for example 10 orders of magnitude, is technically problematic. Also, in the optical area, there are problems with coating on lenses, contamination, and sulfuric acid corrosion. Materials that resist corrosion like high chromium-type alloys, titanium, and even certain types of stainless steel are being used.

EEE Links: How feasible is landing on Venus and making measurements? How long would the instrument last?

Dr. Niemann: Landing on Venus is very feasible and has been done by the Russians and NASA. Limited survival time of perhaps several hours is technically achievable using current technology. Pioneer Venus Probes that landed more than 20 years ago, survived for nearly an hour. Sample returns will follow the in-situ studies; they will involve, for example, landing a probe on the surface, collecting the samples, inflating a balloon to lift the package to a higher altitude, and firing off a rocket that is then captured by an orbiter and brought back to Earth. JPL is currently studying variations on this type of scheme.

EEE Links: What is the science objective for studying Mars?

Dr. Niemann: The Mars mission objective is under intensive study now, especially after finding traces of ancient life. Origin, climate, evolution are all major science objectives. In our group, atmospheric chemistry and dynamics and surface composition are under study (heavy ice has been discovered on the polar cap), and to confirm findings directly, probes must be placed there. We are looking for water and hope to find evidence of past or present biological activity by drilling several meters down below the surface.

EEE Links: How does extreme environment tie into NASA’s two major enterprises, Space Sciences and Earth Sciences?

Dr. Niemann: The instrumentation and scientific experiments are similar in Space and Earth studies, but the advantage for Earth Sciences is that we can afford to fly much larger instruments because they are not going very far from Earth. Also, communication is much easier, so we can get higher data rates.

EEE Links: How can the NEPP Program, with its emphasis on device parts and packaging, address some of the extreme environment challenges?

Dr. Niemann: MEMS, SOI, SiC, and gallium nitride are all technologies that tie into NEPP goals. The packaging itself needs to be examined; ASICS is now popular, but we need analog ASICS. Passive components like electrolytic capacitors are still very vulnerable to temperatures. We would like to do MEMS mass spectrometry and have electronics on the same chip; the small size presents quite a challenge. Communication systems are in the same category—they also need to be miniaturized. Miniaturization is of course less important for instruments that do require large apertures, although smaller and lighter electronics packages would still be very desirable.