ASK OCE — August 31, 2006 — Vol. 1, Issue 13

The three micro-satellites known as Space Technology 5 (ST5), each no bigger than a 13-inch television and weighing a mere 55 pounds, completed their planned 90-day orbital mission on Friday, June 30, when the ST5 mission team shut down the spacecraft.

The main focus of the three-month mission was flight testing miniaturized satellites in the adverse conditions of space and evaluating their ability to make high-quality scientific measurements. The tiny crafts were sent into orbit on March 22, 2006.

A major mission objective was achieved when the spacecraft arrayed themselves in a constellation formation on May 24. The ST5 satellites lined up in nearly identical orbits approximately 220 miles apart. To achieve this formation, seven distinct maneuvers had to be executed utilizing miniaturized micro-thrusters. Each quarter-sized micro-thruster was utilized to adjust altitude and orbit.

The ST5 mission clearly demonstrated the benefits of using a constellation of spacecraft to perform scientific studies of auroral displays near the Earth’s polar regions. Additionally, the micro-satellites simultaneously traversed electric current sheets and measured the magnetic field using miniature magnetometers.

The mission validation team demonstrated the functionality of the miniature magnetometers, as well as an innovative communications technology. The satellites were each equipped with miniature transponders for space-to-ground communications and tracking. The transponders were coupled with conventional and computer-optimized or -evolved antennas. The transponders and antennas performed as intended.

In addition, the satellites’ power systems demonstrated excellent performance, with all lithium ion batteries remaining above 90 percent charge, even during some tests intentionally designed to tax the power system. The high-efficiency solar arrays on all three spacecraft produced more power than predicted prior to launch, and their batteries performed to expectations.

The final days of the mission emphasized the effectiveness of ground system technologies, which are designed to be highly automated to reduce the operating cost of operating multiple spacecraft as a single constellation rather than operating them individually. This new ground system architecture may allow an affordable means of simultaneously flying from ten to hundreds of micro-satellites.

Developed and tested at Goddard, the ST5 mission was part of the New Millennium Program, which develops and tests high-payoff technologies that provide future science mission capabilities with reduced cost and risk. Each flight acts as a test track for competitively-selected technologies, mission objectives and operations concepts. New Millennium is managed for NASA by the Jet Propulsion Laboratory (JPL).