The name was officially an acronym of Satélite de Aplicações CIentíficas ("Scientific Applications Satellite"), but was obviously taken from the Saci character of Brazilian folklore.
The satellite weighted approximately 80 kg. It was a box approximately 60 cm long and 40 cm square, with a circular base plate and surrounded by a metal ring, both about 80 cm in diameter. Besides being a technology testbed, it carried four scientific payloads (PLASMEX, MAGNEX, OCRAS and PHOTO), with a total weight of 10 kg, to investigate plasma bubbles in the geomagnetic field, air glow, and anomalous cosmic radiation fluxes. It was meant to circle the Earth on a circular orbit at 750 km altitude, inclined 17.5 ° from the Equator.
The spin-stabilized spacecraft carried two S-band communication links (a 2W, 256 kb/ s downlink and 19.2 kb/s uplink), and a 48 MB solid state data recorder. It is variously reported to have cost between US$ 800,000 and US$ 1.7 million