Mission Type: Orbiter
Launch Vehicle: Atlas-Centaur (AC-24 / Atlas 3C no. 5405C / Centaur D-1A)
Launch Site: Eastern Test Range / launch complex 36A, Cape Canaveral, USA
NASA Center: Jet Propulsion Laboratory
Spacecraft Mass: 998 kg at launch, about 560 kg in Mars orbit
Spacecraft Instruments: 1) imaging system; 2) ultraviolet spectrometer; 3) infrared spectrometer; 4) infrared radiometer; 5) S-band occultation experiment; and 6) celestial mechanics experiment
Spacecraft Dimensions: Octagonal frame 45.7 cm deep and 138.4 cm across a diagonal. Each pair of the two pair of solar panels spanned 6.89 m from tip to tip. Overall spacecraft height was 2.28 m.
Spacecraft Power: 4 solar panels, with power stored in a 20-amp-hr nickel-cadmium battery
Maximum Power: 800 W at Earth, 500 W at Mars
Antenna Diameter: 1 m (high-gain)
S-Band Data Rate: 16, 8, 4, 2, and 1 kbit/s using two tracks at a time
Total Cost: Total research, development, launch, and support costs for the Mariner series of spacecraft (Mariners 1 through 10) was approximately $554 million.
References:
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi

National Space Science Data Center, http://nssdc.gsfc.nasa.gov/

Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.

Mariner 8 (also called Mariner-71H and Mariner-H) was the first of a pair of American spacecraft intended to explore the physical and dynamic characteristics of Mars from Martian orbit. The overall goals of the series were to search for an environment that could support life; to collect data on the origin and evolution of the planet; to gather information on planetary physics, geology, planetology, and cosmology; and to provide data that could aid future spacecraft such as the Viking Landers.

The launch of Mariner 8 was nominal until just after separation of the Centaur upper stage, when a malfunction occurred in the stage's flight-control system, leading to loss of pitch control at an altitude of 148 kilometers at T+4.7 minutes. As a result, the stack began to tumble and the Centaur engines shut down. The stage and its payload reentered Earth's atmosphere approximately 1,500 kilometers downrange from the launch site.