t that sits 930,000 miles from the Earth on the Sun-Earth line. The coronagraph instrument filters the bright orb to focus on the details of the coronal structure; hence the dark circles in the center. The four panels depict the development of a coronal mass ejection (CME) on 11/6/97. CMEs and solar flares are the two categories of solar disturbances that can result in solar proton events at satellite positions. The two lower panels show the effects of CME protons reaching the coronagraph's CCD. Even though the instrument has heavy shielding to protect the CCD, the > 100 MeV protons from the CME penetrated to the focal plane. Note the range of proton 1997/11/06 12:10(C2) 11:50(C3) 12:36(C2) 12:41(C3) 13:30(C2) 13:46(C3) 14:26(C2) 14:12(C3) SOHO/LASCO Figure 12. Coronagraphs from the SOHO satellite follow the evolution of a coronal mass ejection. Protons from the event reach the instrument's CCD and "pepper" the image with transients in the lower two panels. IV-30 transient sizes and path trajectories indicating apparent omnidirectional arrival. Also note that the images are from different frames, and the proton transients are not repeated in the same image locations. For this reason, temporal filtering techniques can minimize the interference from the proton strikes for star trackers and other applications requiring tracking of bright objects against a cluttered background. More can be found on these images at the website, "sohowww.nascom.nasa.gov". 4.2.2 Optical Link Photodetectors: In recent years several missions have implemented fiber-optic based local area networks for spacecraft telemetry and control busses as well as high data rate payload busses. Data transmission via optical fiber offers advantages in terms of power savings and reduced electromagnetic interference concerns, and these issues become increasingly important at data rates in the Gbps regime. The optical signal level representing a digital "1" may contain very little energy. When received at the link's terminal and converted back to an electri