They are three very small satellites, called the Nanosat Constellation Trailblazer mission, and today NASA selected them as the agency's latest New Millennium mission. The mission will validate methods of operating several spacecraft as a system, and test eight technologies in the harsh space environment near the boundary of Earth's protective magnetic field, or magnetosphere.

Each Trailblazer spacecraft will be an octagon 16 inches across and 8 inches high, and each will have booms and antennas that will extend after launch. The mission will cost $28 million and will be launched in 2003 as a secondary payload on an expendable launch vehicle. The mission is managed by NASA's Goddard Space Flight Center, Greenbelt, MD.

Results from the Trailblazer mission will be used to design future missions using constellations of lightweight (about 44 pounds), highly miniaturized autonomous spacecraft. One proposed constellation of up to 100 spacecraft positioned around the Earth will monitor the effects of solar activity that can affect spacecraft, electrical power and communications systems. Others will study global precipitation and the atmospheres of other planets.

The Nanosat Constellation Trailblazer is the fifth in the agency's New Millennium program, which tests technology for future space and Earth science missions. The program's goal is to dramatically reduce the weight, size and costs of missions while increasing their science capabilities.

• A miniature communications system to determine the positions of the spacecraft using the Global Positioning System (NASA's Jet Propulsion Laboratory, Pasadena, CA, and Cincinnati Electronics Corp., Mason, OH).
• A set of software that automatically operates the spacecraft and determines orbits (Bester Tracking System, Emeryville, CA).
• A communications system component that uses one-fourth the voltage and half the power, weighs 12 times less and is nine times smaller than proven technology (Aero Astro, Boston, MA).
• A new method of connecting electrical lines that saves weight (Lockheed Martin, Denver, CO).
• A new type of microelectronic device that is more reliable and uses 20 times less power than proven technology (Goddard Space Flight Center and the University of New Mexico, Albuquerque).
• An electrically tunable coating that can change its properties from absorbing the Sun's heat when the spacecraft is cool to reflecting or emitting heat when needed (Goddard Space Flight Center and the Johns Hopkins University Applied Physics Lab, Laurel, MD).
• A very tiny microelectromechanical system chip that provides fine attitude adjustments on the spacecraft using 8.5 times less power and weighing less than half as much as proven systems (Marotta Scientific Controls, Montville, NJ).
• Development of a Lithium Ion Power System for Small Satellites. A rechargeable lithium ion battery that stores two to four times more energy and has a longer life than proven technology (Yardney Technical Products, Pawcatuck, CT).

"Not only could these technologies make future missions more productive and less expensive, some could become consumer products," said Dr. Dana Brewer, New Millennium Program Executive, NASA Headquarters, Washington, DC. "For example, the variable-emittance thermal-control system is a coating applied to surfaces such as automobile windows which becomes highly reflective when you apply an electrical current to it. It blocks out a lot of the sunlight, keeping it cooler inside a car."