Hubble to Receive High-Tech James Webb Space Telescope Technology

Scientists and engineers now creating new technologies for NASA's James Webb Space Telescope have realized they can be used to enhance the Hubble's Advanced Camera for Surveys (ACS) in the upcoming servicing mission.One piece of new technology astronauts will be installing in Hubble during Servicing Mission 4 in May, 2009 is a small, specialized integrated circuit called an Application-Specific Integrated Circuit, or ASIC, that enables an entire circuit board’s worth of electronics to be condensed into a very small package. It will be a part of the new Charge-Coupled Device (CCD) Electronics Box (CEB) that will be installed to repair the failed ACS instrument. The ASIC is used to read the voltages generated by instrument detectors and convert them to digital signals that are processed by the spacecraft’s electronics for transmission to the ground.The ASIC design is the same as the one already developed and tested for the James Webb Space Telescope. However, the electronics packaging for Hubble is different because of the different operating conditions such as temperature and electronics environments. How different are the thermal environments? Hubble is in low Earth orbit, approximately 350 miles above the Earth’s surface, while the Webb telescope will have an orbit one million miles from Earth. In addition, Webb uses infrared based cameras that will be adversely affected by heat given off by circuitry. ASIC consumes very low power, which helps keep the Webb telescope's science instruments cold. Hubble's ACS is sensitive to electromagnetic radiation at visible and ultraviolet wavelengths, but not infrared radiation. Its Charge-Coupled Device (CCD) detectors must also be cooled to minimize the background thermal noise produced by the warmth of the detector assemblies themselves. However, the CCD’s are not nearly as sensitive to heat as the James Webb infrared sensors.