Embedded Systems in Space Exploration
Twenty years ago in April 1990, NASA launched the Hubble Space Telescope (HST). Over these past two decades, the Hubble observed over 300,000 objects in space, and took over half a million pictures.
HST orbits the Earth every 96 minutes, and is 360 miles above the Earth’s surface. It has circled the Earth about thirteen times a day for twenty years. Yet, it has only been serviced five times. Imagine the family car going that long with only five service calls. The Space Shuttle performed maintenance on it for the last time in July 2009.
As the Space Shuttle program comes to a close so does the future of the Hubble Telescope. With no further shuttle service calls, the Hubble’s orbit will deteriorate, and it will breakup in the Earth’s atmosphere.
In preparation, NASA has been designing the James Webb Space Telescope (JWST) for deployment around 2013 or 14 to replace the Hubble. Its mission is to study the origins of the universe, and the formation of galaxies and solar systems. Building the new telescope requires the cooperation of NASA, the European Space Agency (ESA), the Canadian Space Agency (CSA), and over thirty technology companies designing embedded systems.
Unlike the Hubble Telescope, JWST will be launched using an Ariane 5 rocket, rather than the Space Shuttle. JWST will be deployed about one million miles from earth. If anything goes wrong, a repair team will not be available to fix it. Therefore the embedded systems included on the JWST must be well designed and reliable. The planned life expectancy of the telescope is ten years.Continued on the next page