Just as Sputnik 1, which was launched on Oct. 4, 1957, was the first earth-orbiting artificial satellite that led to the creation of space age, an old Russian spacesuit went into orbit on Feb. 3, 2006 to spark a new era. Before we know it, intelligent robots would be orbiting the earth to send us all kinds of information that was unthinkable until now.

On Feb. 3, just before 6 p.m. EST, the crew aboard the International Space Station (ISS) deployed an unusual satellite into space. During a planned space walk, the two station crewmembers, space station commander Bill McArthur and flight engineer Valery Tokarev, released an unoccupied old Russian Orlan spacesuit into space as a satellite orbiting earth. Called SuitSat-1, this new satellite, a Russian idea to turn old space suits into useful satellites, was designed to help scientists determine the durability of spacesuits, the life of batteries that power the suit, and if a tumbling suit affects the clarity of transmission. For that, the SuitSat-1 was fitted with a radio transmitter, a controller, sensors to measure temperature and battery power, and three 28 V batteries. Recorded greetings of students from Paint Branch High School and Eastern Middle School in Silver Spring, Md., were transmitted along with temperature and battery power as telemetry messages. The greetings were in English, French, Japanese, Russian, German and Spanish.

Only an antenna and a radio receiver that could tune to 145.990 MHz FM was needed to receive the transmitted signals. Awards will be given to students who have correctly identified the coded messages.

This project was sponsored by an international working group called Amateur Radio on the International Space Station (ARISS), which consists of volunteers from national amateur radio societies and the internationally based Radio Amateur Satellite Corporation (AMSAT), along with the Russian space agency and NASA.

Microchip Technology engineers, under the supervision of principal applications engineer Steve Bible, played a key role in designing and developing the controller board, which uses a PIC18F8722 microcontroller, an MCP9800 temperature sensor and MCP6022 op-amps. Voices and telemetry messages are stored in a single eight-Mbit flash EPROM. Likewise, the switchbox was also designed and assembled at Microchip. However, the transmitter was built around a Kenwood handheld amateur radio (model TH-K2) by an ARISS team led by retired NASA engineer Lou McFidan. The complete communication system used in the SuitSat-1 is shown in Figure 1.

The battery pack was removed and the radio was mounted on a block of aluminum that acts as a heat sink (Figure 2). The radio is powered from the controller box (12 V regulated from 28 V). The frequency of the radio was set to 145.99 MHz, power output was set to 500 mW, and the front panel was locked to prevent inadvertent changing of the settings. The radio is only used as a transmitter, no receive capability was built into SuitSat-1. The ARISS team also designed and developed the antenna, which is supposed to be a standard quarter-wave ground plane antenna design used by ISS. While all the electronics are made to fit inside the suit, the quarter-wave antenna and the switch box are fitted onto the helmet with special techniques. The switch box is attached to the helmet via a specially made bracket, and is connected to the controller box via a cable.

According to Microchip, two complete flight units were integrated and shipped to NASA in Houston, Texas for further shipping to Russia for final testing and certification. Note that the Orlon space suit and batteries reside on the ISS.

As you can see, all the components and ICs used in this project are commercial off-the-shelf parts. No rad hard devices were used in this project. However, they have been carefully selected, tested and repackaged to withstand the rigors of space. It also was noted that the output power was less than desired; not sure whether it was the antenna or the radio or the connection between the two. Last checked on Feb. 15, the Suitsat-1 was still sending telemetry signals and was being tracked. The battery voltage was 26.0 V and the temperature was 15°C.

Lessons learned from this experience will be used to design the SuitSat-2, which is expected to be launched in 2007, stated Microchip's Bible.

For more on Suitsat audio recordings from around the world, visit www.aj3u.com/blog

For more on Suitsat, go to www.suitsat.org