The TDRS satellites relay large volumes of user satellite data - including voice, television and scientific - from manned missions or orbiting scientific spacecraft back to ground control centers. TDRS supports spacecraft with research targets ranging from the birth of stars deep in distant galaxies to the subtleties of environmental phenomena on Earth. Though research approaches and instruments of these spacecraft vary widely, TDRS' two-way communications will serve all low- and medium-orbit customer vehicles generating this ground-breaking information. The TDRS fleet is also unique in its ability to follow the motion of fast moving satellites, providing nearly continuous communication with controllers and researchers on Earth.