Luna 14 successfully entered lunar orbit at 1925 UT on April 10, 1968. Initial orbital parameters were about 99 x 168 miles (160 × 270 kilometers) at 42 degrees inclination.
The primary goal of the flight, like its predecessors (Kosmos 159 and the launch failure in Feb. 1968), was to test communications systems in support of the N1-L3 piloted lunar landing project. In addition, ground tracking of the spacecraft’s orbit allowed controllers to accurately map lunar gravitational anomalies to predict future trajectories of future lunar missions such as those of the LOK and LK lunar landing vehicles.
Luna 14 also carried scientific instruments to measure radiation near the Moon, a “tissue dosimeter for studying doses of ionizing radiation,” as well as technical elements of the future Ye-8 lunar rover, in particular, the R-1-1, R-1-2, and R-1-3 gear pairs (both steel and ceramic), various types of ball bearings with lubrication to test drives, and the M-1 drive shaft.
The mission was slated to last 30 days but spanned 75 days; the entire program was fulfilled as planned, and allowed designers to make the final selection for elements of the Ye-8 lunar rover chassis.
Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.