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Technion developing better controls for satellites

Posted By ISRAEL21c Staff On January 14, 2002 @ 12:00 am In | No Comments

Although more than 26,000 satellites have been launched, technologies for controlling them are comparatively primitive.Although more than 26,000 satellites have been launched, technologies for controlling them are comparatively primitive.

Technion – Israel Institute of Technology is teaming with researchers from Cornell University to develop a new series of satellites and is testing new methods for controlling them. If successful, the methods may be incorporated into future U.S. satellites.

Since the first satellite was launched in 1957, more than 26,000 satellites have been sent into space. But despite the widespread use of satellites and the resources invested in them, methods for maintaining the balance of satellites in orbit are relatively primitive.

An innovation developed by a research team from the Asher Space Research Institute at the Technion could solve a significant part of the shortcomings of the current method. The team, led by Asher head Prof. Moshe Guelman and Prof. Mark Psiaki of Cornell University in Ithaca, N.Y., is developing a new method to keep satellites balanced.

Most satellites can be divided into two main groups: Those that are always located over one spot on earth, known as geosynchronized satellites; and others that travel over different places on earth and require control of their position relative to earth.

Precise control of the angle at which a satellite faces earth is critical to the satellite’s operating successfully. For example, if a satellite’s cellular plates that serve as power sources are not turned towards the sun, the energy for the operation of the satellite will run down. If the transmitter installed on the satellite is not facing earth, signals transmitted from the satellite might not be received.

There are two main methods for controlling the angular status of a satellite. The first, in use today, is based on the principle of a gyroscope. Part of the satellite is in constant motion, enabling it to remain at a certain angle despite the spin of the earth. This method is in widespread use in active satellites, but it is very difficult and costly in very small satellites.

A second method has existed for decades, but its usage has been limited for various reasons. This method is based on using electromagnetic poles connected to the satellite, which are activated by signals created by the satellite’s computer. Because of the magnetic field of earth, the poles are drawn towards earth’s magnetic field or distanced from it to adjust the entire satellite’s motion. Correct use of electromagnetic poles could be a more cost-efficient method for maintaining the position of satellites in orbit.

The Technion experiments are based on that method. The potential breakthrough in this experiment is in the development of new control systems that take advantage of the new knowledge about earth’s magnetic field and could solve a great deal of the previous limitations associated with this method.

The idea of improving control methods based on usage of electromagnetic poles for satellites designed in the United States was the brainchild of Prof. Psiaki. Psiaki and the Technion teamed up after the launch of Gurwin TechSat II, a mostly student-built Technion satellite launched in July 1998. Gurwin TechSat II is used to conduct a wide variety of experiments, including various control methods for small satellites.

Despite its innovative image, the space industry is really quite conservative, because of fear of failure on the part of researchers and project managers. An unsuccessful project could result in the loss of millions of dollars.

The U.S. team found that the Technion team had the enthusiasm to test new ideas. If the control methods now being tested at the Asher Institute and on the Technion satellite are successful, those methods may be incorporated into the next generation of U.S. satellites.

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