Within two weeks, the Genesis spacecraft, launched on August 8, will arrive into orbit around its destination -- Lagrange 1, a point in space between Earth and the Sun. The spacecraft is now preparing to begin its science mission.
Project managers are monitoring the temperature of the battery inside Genesis' sample return capsule to make sure that long-term heating does not impair its performance when the capsule returns to Earth in September 2004. Although the battery is likely to become hotter than originally expected, the flight team has a number of options for managing the battery's temperature, and they do not expect the issue to affect the mission.
The mission's science requirements call for 22 months of solar wind particle collection. "In our current plan Genesis will meet and exceed that goal, collecting up to 26 months' worth of solar wind particles," said Chet Sasaki, Genesis project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
The temperature of the lithium-dioxide battery is currently at 23 degrees Celsius (73 degrees Fahrenheit), within the range anticipated by spacecraft designers. A radiator device intended to shield the battery is not working as well as expected, however, and the battery is likely to heat up to 42 degrees Celsius (108 degrees Fahrenheit). Mission managers consider this temperature to be within acceptable limits. They note that similar batteries have been maintained at 60 degrees Celsius (140 degrees Fahrenheit) for 15 months without impairing their performance. Ground tests are being conducted on lithium batteries to measure their durability at various temperatures.
The Genesis project team has been attempting to bake potential contaminants off the battery's radiator by heating the area. They are doing this with the spacecraft's sample return backshell opened just enough to allow gas trapped inside the capsule to escape, while still avoiding exposure to the Sun.
Following arrival into orbit around the Lagrange 1 point on November 16, Genesis will deploy its collector arrays in early December and begin collecting particles of the solar wind that will imbed themselves in specially designed high purity wafers.
JPL, a division of the California Institute of Technology in Pasadena, manages the Genesis mission for NASA's Office of Space Science, Washington, D.C. Lockheed Martin Astronautics, Denver, Colo., designed and built the spacecraft and operates it jointly with JPL. More information is available online at http://genesismission.jpl.nasa.gov and http://www.jpl.nasa.gov .