# National Aeronautics and Space Administration

## NASA eClips: How the Hubble Space Telescope is Powered in Space

Learn how NASA uses light from the sun to make electricity to keep the Hubble Space Telescope powered in space. Scientists use an equation to balance the power in the solar panels and batteries.

 Interview with NASA Aerospace Engineer, Art Whipple, who describes how batteries are used to supplement Hubble's power demands when sunlight is not available. The battery power supply has to be exactly balanced by the various power demands of the satellite, such as the operation of the gyro stabalizers, communications and telemetry systems, and telescope systems. This addition of all the power 'loads' by the satellite, when added to the amount of power supplied by the battery, produces an equation that gives the rate of discharge of the battery given by the equation Rate = Supply - Load. The satellite has to be designed so that the battery being used does not 'discharge' below a critical level when the solar panels are not supplying electricity. If the discharge is 'too deep', the battery cannot be charged back up to its original capacity each time the satellite goes into the night-side of Earth, and within a few of these eclipses, the battery will be damaged. (7 minutes)

## Related Mathematics Problems

These problems provide a mathematical introduction to some of the issues related to the use of solar energy in space.

Satellite Power Loss and the Hubble Space Telescope The Hubble Space Telescope is located in a low-Earth orbit at an altitude of about 370 kilometers, with an orbit period of about 90 minutes. The constant impact of high-energy particles on the solar panels causes a steady decrease in the power output of these panels over time. Students will study a graph showing the power from the solar panels between 2002 and 2006 and determine the rate of decrease of the power each year, and use this calculated rate to forecast the available power by the end of the mission in 2015. [Grade: 6 - 8 | Topics: Slope; percentage change; forecasting] [Download PDF]

Solar Power and Satellite Design Students perform simple surface area calculations to determine how much solar power a satellite can generate, compared to the satellite's needs. [Grade: 6 - 8 | Topics: Area of irregular polygons] [Download PDF]

Additional problems are available if you are a registered SpaceMath@NASA Educator