Design
| Enviro |
Astro | Propulsion
| Power | Thermal
| Structures | AD&C
| CDHS |
Test
The
following have standardized TT&C networks
with multiple ground stations
worldwide:
NASA/Caltech JPL Deep Space Network (DSN); NASA
Tracking and Data Relay Satellite System (TDRS);
NASA Goddard Spaceflight Tracking and Data Network
(GSTDN); and the Air Force Space Ground Link System
(SGLS).
Tracking,
Telemetry and Command
Tracking
data consists of spacecraft direction given in azimuth
and elevation, range and line-of-sight velocity
or range rate information.
Telemetry
consists of health and status information from the
spacecraft bus and payload, such as temperatures,
currents, voltages, switch positions and CPU memory
state.
Command
subsystems are designed for high reliability to
assure ground control stations have the ability
to do such things as desaturate gyros, fire rockets
and turn payload sensors on. Robotic spacecraft
are taking over many of these tasks as autonomous
decision-making software technologies evolve, like
those flight tested onboard NASA/Caltech JPL
DS1.
