As previously discussed, the NWA 773 clan OC is younger than most lunar rocks in the present collection of Apollo and Luna samples and lunar meteorites.
The cratering chronology formulated by relating crater frequencies to the radiometric ages of Apollo and Luna samples enables us to convert the crater frequencies into absolute model ages (e.g., Hartmann, 1970 , 1972 Neukum et al., 1975; Neukum, 1983; Neukum and Ivanov, 1994; Stöffler and Ryder, 2001).
A special study of the Luna 24 samples should be undertaken designed to find records of the formation age of the crater on whose rim Luna 24 landed, thus better constraining the age of GB crater.
Apollo and Luna mare basalt samples indicate that lunar mare volcanism was active at least from 4.3 to 3.2 Ga, after feldspathic crustal formation (e.g., Spudis and Pieters 1991; Nyquist and Shih 1992; Shearer et al. 2006).
After the incubation at room temperature for 10 minutes, the yeast staining solution was loaded onto the counting slide of Luna-FL™ and the loaded yeast sample images were acquired from Luna-FL™.
Analyses of samples from the Luna missions have continued as well and are valuable because they were collected from eastern equatorial areas far from the Apollo sites.
Also on Plescia's to-do list is searching for Luna 18, a 1971 Soviet sample-return mission that failed.
The last one before that was the Soviet Union's Luna 24 mission, sent to collect samples in 1976.
A 20 μL volume of each sample was injected into a Luna 5 μm HILIC 200 Å 250 × 4.6 mm LC column (Phenomenex, Torrance, CA).
Five microliters of each extracted sample were injected onto a Luna Aminopropyl, 3 μm, 150 × 1.0 mm i.d.
