The SAC-C spacecraft is an international mission to study the structure and dynamics of the Earth's atmosphere, ionosphere and geomagnetic field. SAC C's scientific mission is to:

• Provide multispectral images of the Earth in order to monitor the condition and dynamics of the terrestrial and marine biosphere and environment
• Develop and utilize new GPS based techniques to globally measure atmospheric phenomena for the study of weather, seasonal, inter-annual and long term climate change
• Enhance the understanding of the Earth's magnetic field and related Sun-Earth interactions
• Measure high energy radiation environment, trapped particle intensities and energy distribution and correlate them with the degradation of advanced electronic components

The SAC C payload comprises 11 different instruments. NASA is responsible for two instruments/components of the SAC-C complement. The two NASA provided instruments are both provided by JPL,

The SAC-C mission logo. Photo: NASA-GSFC

The GPS Occultation and Passive Reflection Experiment (GOLPE) instrument. It consists of a TurboRogue III GPS and four high gain antennas, each facing in different spacecraft orbital directions. The GPS will study the Earth's gravity field by producing post-processed decimeter-level SAC-C orbit measurements. GOLPE will demonstrate and utilize GPS remote sensing to study weather and seasonal to long term climate change. GOLPE also will measure refractivity or bending of GPS signals hidden by Earth's atmosphere and ionosphere. GOLPE is an advanced GPS receiver capable of automatically acquiring selected GPS transmissions that are refracted by the Earth's atmosphere and reflected from the Earth's surface.

The Scalar Helium Magnetometer (SHM) will be part of the Danish Magnetic Mapping Payload (MMP). The SHM will complement other MMP instruments and will be mounted at the tip of the Danish extendable boom. The SHM electronics box will be mounted on the spacecraft's lower (propulsion) platform.

Non-NASA Instruments
The MMP is designed to better understand the Earth's geomagnetic field and related Sun-Earth interactions The MMP will provide continuous field measurements for a minimum of 12 months with an accuracy of one part in 50000. The MMP will be shipped from Denmark to Argentina as a complete unit including U.S. supplied hardware.

Mulitspectral Medium Resolution Scanner (MMRS), provided by the Argentines will study the condition and dynamics of the terrestrial and marine biosphere and environment. The MMRS will be operational over Argentina during SAC-C's lifetime.

High Resolution Technological Camera (HRTC) will improve part of the MMRS scenes. The HRTC will be operational over Argentina during the lifetime of SAC-C.

Influence of Space Radiation on Advanced Components (ICARE) experiment will measure high energy radiation environment, trapped particle intensities and energy distribution and correlate them with advanced electronic components degradation. ICARE will be able to conduct regular environment characterization campaigns for ten days every six months and exceptional ones during solar events. ICARE will study the effects on components and their variations along the same time frame.

Italian Star Tracker (IST) will test a fully autonomous system and orbit determination using a star tracker.

Whale Tracker Experiment will track the migratory route of the Franca whale. The experiment will be operational when the spacecraft is over the South Atlantic Ocean.

Italian Navigation Experiment (INES) and its components will be the primary navigation sensor by the SAC-C attitude and orbit control subsystem and a secondary attitude determination sensor.

Data Collection System will enable SAC-C to collect environmental data from low cost ground platforms.

Digital Transponder for Radio Amateur Communications will allow radio amateur communications.

High Sensitivity Camera (HCS) is a highly sensitive intermediate resolution camera. The HCS will be useful in forest fire and electrical storm detection.