- First spacecraft to successfully land on Mars - July 20, 1976
- Conducted the first successful biological experiments on the Martian surface
- Sent back about 5,400 images of the Martian surface in the first part of its mission from orbit around Mars and about 33,000 high-resolution color images after landing
- Detected organic molecules within soil on Mars
- First spacecraft powered exclusively by the heat of a radioisotope thermoelectric generator (RTG).