San Marco D/M

The primary purpose of the research satellites San Marco -D/M and -D/L was to explore the relationship between solar activity and meteorological phenomena, with emphasis on lower atmospheric winds and thermosphere-ionosphere phenomena from low (San Marco-D/L) and multistationary (San Marco-D/M) orbits. Two Scout launch vehicles inject both spacecraft into mutually predetermined orbits. Both spacecraft have planned mission lifetimes of 1.5 years.

San Marco-D/M is built around a single experiment. The purpose of this spacecraft is to monitor cloud cover and ozone content. With one-third the period of an earth-synchronous or stationary satellite, observations may be repeated three times per day.

The general appearance of SM-D/M is that of two cylinders with a common axis, one with a diameter of 70 cm and height of 40 cm, with the second cylinder extending from the end of the first for an additional 42 cm and with a diameter of about 32 cm. The surface of the larger cylinder is covered with 1296 solar cells that feed 2 rechargeable battery packs. The spacecraft is spin stabilized along the axis of its cylindrical structure, and scanning operation for the instrument is dependent upon the satellite spin.