Mission Type: Lander, Sample Return
Launch Vehicle: Proton booster plus upper stage and escape stages, 8K82K + Blok D (Proton-K no. 285-01)
Launch Site: Tyuratam (Baikonur Cosmodrome), USSR, NIIP-5 / launch site 81P
Spacecraft Mass: About 5,800 kg
Spacecraft Instruments: 1) stereo imaging system; 2) improved drill for sample collection; 3) radiation detector; and 4) radio-altimeter
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.

Luna 23 was the first modified lunar sample-return spacecraft, designed to return a deep-core sample of the Moon's surface (hence the change in index from Ye-8-5 to Ye-8-5M). While Luna 16 and 20 had returned samples from a depth of 0.3 meters, the new spacecraft was designed to dig to 2.5 meters.

After a midcourse correction on 31 October, Luna 23 entered orbit around the Moon on 2 November 1974. Parameters were 104 x 94 kilometers at 138° inclination. Following several more changes to the orbit, the spacecraft descended to the lunar surface on 6 November and landed in the southernmost portion of Mare Crisium. Landing coordinates were 13° north latitude and 62° east longitude.

During landing in unfavorable terrain, the lander's drilling device was evidently damaged, preventing fulfillment of the primary mission, the return of lunar soil to Earth. Scientists devised a makeshift plan to conduct a limited science exploration program with the stationary lander. Controllers maintained contact with the spacecraft until 9 November 1974.