By the middle of next week, Moshe Guelman hopes to be toasting the successful launch of a 106-pound satellite. He knows that with only one satellite, a smooth takeoff isn�t always a sure bet.
The satellite, TechSatII, is the second coming of microsatellite technology developed by the Technion-Israel Institute of Technology. Its predecessor, TechSatI, was launched in 1995 aboard a converted Russian Intercontinental Ballistic Missile. But the rocket never made its orbit, and the satellite was lost. Nevertheless, Guelman believes that ill-fated mission was not a total loss. "We gained a lot in experience," said Guelman, a professor of aerospace engineering at the institute.
That experience translated into the development of a microsatellite that will function as an orbiting laboratory for scientific experiments and satellite-technology tests.
Once the province of scientists and hobbyists, small satellites are now the cosmic darlings of government and industry, because they are cheaper and faster to produce than the larger geostationary satellites often used for broadcast systems. For example, production time for GEO satellites is typically measured in months, but smaller low-Earth orbit systems have a faster turnaround time. Iridium churned out one satellite every five days, once its production line was up and running.
Small satellites are distinguished by weight. Microsatellites weigh between 22 and 220 pounds. By contrast, a GEO satellite can weigh more than 10,000 pounds at launch. Heavier satellites require more fuel for propulsion which takes up room on the craft. With the lighter satellite, less fuel and rocketry are required to remain aloft, and a developer can put more scientific instruments on board -- a principle NASA is putting to use in its own New Millennium Program.
"[TechSatII] is no different than what NASA is doing with Deep Space 1," noted Guelman. "We are doing what [NASA Administrator Daniel] Goldin is talking about ... better, cheaper, faster."
TechSatII, which will orbit at a height of 183 miles, will have instruments onboard for a variety of experiments, like X-ray imaging technology to examine the cosmos and an ultraviolet sensor to determine the ozone content of the atmosphere over the Middle East. These instruments will run on more than 10 watts of power generated by four solar panels. Although the panels will generate a total of 20 watts, Guelman said the satellite needs less than 10 watts for its normal operations, a huge power savings.
"Generally, it takes four to five watts per kilogram to power a satellite �- that�s five times what we use," Guelman explained.
All the more power to test out technologies that will improve general satellite operations. One problem plaguing smaller satellites is that they complete an orbit several times each day, therefore absorbing more radiation than their bigger and less mobile brethren. This reduces satellite life. For example, Teledesic satellites have an average lifetime of seven years, but Intelsat�s GEO satellites have a life cycle of up to 14 years.
The TechSatII will carry a charged particle detector that will monitor the radiation levels the satellite encounters. From this data, Guelman and his colleagues hope to figure out how to improve a satellite�s durability.
TechSatII will also have its own tracking system, something rare for satellites. Typically, satellite developers must rely upon North American Aerospace Command. Guelman hopes this system will be the start of giving these smaller satellites a certain measure of autonomy.
But, first, there�s the matter of getting TechSatII into space. The three years since the first, ill-fated launch has brought improvements in launch technologies, namely, a rocket designed to take satellites to their orbits. The ICBM used in 1995 was "not a real launcher," Guelman noted. This time out, the blast-off button will send a Russian Zenith rocket from the Kazakhstan launch pad.
The failed attempt also demonstrated the importance of insurance. Guelman said the current project is covered by a US$2 million policy, which he estimates will provide $450,000 for the launch, plus $1.5 million towards building another satellite.
