The CANEUS 2006 Conference opened many eyes to one fact: Nearly every space program worldwide has found remarkable and successful roles for micro and nano technologies (MNTs). It's in response to the lighter-weight, smaller-size, less-power-dissipation, lower-cost mantra chanted by those involved with commercial outer-space, aerospace, and military applications.
Held in Toulouse, France from Aug. 27 through Sept. 1, CANEUS included many technical presentations and exhibits. Participants discussed the technology readiness level (TRL) of materials, devices, subsystems, and systems. U.S. government agencies use TRL to assess the maturity level of evolving technology items, from conception to implementation.
Simply put, MNTs have come to the fore because they're the only technologies that can meet space and defense needs. Nino Dastoor of NASA's Exploration Systems Directorate underscored this point during his keynote address. "NASA is in the business of managing and achieving program goals," he said. "It is not necessarily in the business of using or targeting any specific technology. It simply uses whatever technology meets our needs."
Since the launch of the Cassini and NEAR (Near Earth Asteroid Rendezvous) space probes, with weights averaging hundreds of kilograms, NASA has come up with space-probe designs averaging 100 kg. The agency hopes to bring this down to about 10 kg for future micro spacecraft probes, mainly through the use of MNTs.
According to Daniel Ludwig, head of the Technical Division of the Galileo Programme joint initiative of the European Commission (EC) and the European Space Agency (ESA), satellites like the NEAR probe should benefit from MNTs. Designs have already been shown with navigation payloads of just 115 kg, power dissipation of only 780 W, and dimensions of just 2.7 by 1.2 by 1.1 m. Meanwhile, processing and storage capabilities were increased, leading to longer lifetimes and lower costs.
The Galileo Programme will feature a constellation of 30 satellites in three medium-earth orbits (MEOs), and it will be interoperable with U.S. satellites. Cooperative agreements also were reached with many other countries worldwide. These satellites are part of a class of space probes known as global navigation satellite systems (GNSSs).
The Microlink 1, crafted by Swedish Angstrom Aerospace Corp., is an excellent example of a nanosatellite built with advanced technologies like MNTs (Fig. 1). It has been used as part of EADS Corp. (the parent company of Airbus Industries) and ESA programs.
Researchers from the Surrey Space Centre at the United Kingdom's University of Surrey propose the use of an all-CMOS chip— codenamed "SpaceChip"—to foster the development a single-chip satellite. Its notational chip configuration includes imaging, a solar cell, antennas, a digital radio, a CPU, and power-control circuitry on a die that measures just 18 by 20 mm (Fig. 2).
GROWING ROLES FOR MEMS AND NANO
Work is ongoing at EADS' Astrium Ltd. Division regarding a modular integrated packaging approach for space microsystems called "micropacks." Suites of microsystem technology (MST) commercial off-the-shelf (COTS) sensors are assembled and integrated into a 3D modular multilayer ceramic package.
This approach allows for the easy inclusion of additional sensors and hardware like MEMS gyros, scientific instruments, and advanced micropower and data-communications networking techniques, as well as a microcomputer on a chip.
Together with the U.K.'s Central Research Laboratory and the Swedish Institute of Space Physics, Astrium presented the preliminary results from an ESA-funded study on nano-satellite space beacons for weather monitoring using MEMS. They showed off conceptual GTO and L1 nanosatellites using CFRP-wound (carbon-fiber reinforced plastic) structures that enable simple instrument/ subsystem interfacing (Fig. 3).
MEMS devices figured heavily in spacecraft propulsion, thrust, and rocket designs of all types. France's Laboratory for Analysis and Architecture of Systems (LAAS-CNRS), Japan's Tohoku and Kyushu universities, and the University of Singapore are investigating MEMS rocket array projects. Kyushu's proposed MEMS rocket array thruster uses a diazodinitrophenol (DDNP) propellant and a polydimethylsiloxane (PDMS) tank/nozzle and membrane structure.
Nanotechnology also will factor in stronger and more durable materials for future space missions. The technology is already used to create lighter, more flexible body armor in several military applications. The lighter weight provides a large protection advantage. Nanomaterials form the foundation for higher-strength coatings used on aircraft, ships, tanks, and artillery weapons systems.
And, research is under way to create nano materials that can both detect and resist chemical weapons. Eventually, researchers hope to develop multiplepolymer nano materials whose molecules in a soldier's uniform can neutralize specific chemicals.