Miniaturization

views updated

Miniaturization

Space exploration is an expensive and risky business. All too often, probes malfunction once they leave the ground; launching a satellite costs many millions of dollars at a minimum, and prices increase with payload weight. Designers feel constant pressure to keep spacecraft as efficient and cost-effective as possible.

To solve these problems, engineers are finding new ways to miniaturize spacecraft components, often pursuing branches of science that are still in their infancy. But the potential benefits for both the space program and private industry are driving a concerted effort toward smaller, more advanced technology.

Nanotechnology

The capability to construct nanometer-sized materials promises to have tremendous impact on space exploration and industry. Scientists are still learning to manipulate nanomaterials, but one promising creation is a form of carbon called a nanotube. These cylinder-shaped molecules are not only unusually strong, but also have potential as semiconductors , which could make them ideal candidates for both the next generation of spacecraft hull and the computers inside them. Composite materials that incorporate nanotubes could dramatically reduce the weight of launch vehicles and commercial aircraft, cutting fuel requirements by 25 percent or more. NASA is also trying to develop sensors based on nanoscale devices. These would potentially be sensitive enough to detect a single molecule of a substance, while still being microscopically small.

In the long term, scientists may be able to exploit the characteristics of biological systems to create materials that actually assemble themselves—without need for manufacture. Such materials would also have the ability to "heal themselves" after being damaged, increasing the durability of the aircraft or spacecraft.

Computer Microsystems

It is predicted that within ten years, the silicon switches on chips will be made of single molecules, at which point silicon will reach its physical limits as a semiconductor. While other materials such as nanotubes could help augment silicon, other innovations in computer design can help shrink systems as well.

Systems on a chip will replace circuit boards with many discrete components, leading to much smaller and lower-power systems with higher reliability. A current example is a digital camera on a chip that includes the imager, all control electronics, and an analog-to-digital converter—all on the same silicon chip. Navigation systems built around this technology can guide spacecraft, and also can help soldiers and firefighters position themselves.

Micro Power Sources

Powering a spacecraft under the extremes of heat, cold, and radiation levels encountered on a mission has always been challenging, but it is even more so when the power source has a size limitation. The only miniaturized power sources currently available are electrochemical batteries (which have a limited lifespan) and solar cells (which lose their effectiveness when far from the Sun or in a planet's shadow).

Two potential solutions are thermoelectric power, which converts heat energy into electricity; and alpha-voltaic power, which converts the kinetic energy of alpha particles emitted from a radioactive isotope. While still under development, these methods could produce chip-sized, solid-state power supplies that could have applications on Earth whenever battery lifetime and environmental limitations play a role.

see also Communications, Future Needs in (volume 4); Mars Missions (volume 4); Nanotechnology (volume 4); Scientific Research (volume 4); Space Industries (volume 4); Vehicles(volume 4).

Chad Boutin

Bibliography

1999 Annual Report of the Center for Integrated Space Microsystems. Pasadena, CA: JetPropulsion Laboratory, 1999.

Goldin, Daniel S. Statement before the U.S. Senate Subcommittee on Science, Technology, and Space, Committee on Commerce, Science, and Transportation. September 23, 1998.