The HFE involved the drilling of two holes into the lunar surface and emplacement of thermometers which would measure how much heat was flowing from the lunar interior. This was the third attempt to emplace a HFE: the first flew on Apollo 13 and never reached the lunar surface, while on Apollo 15, problems with the drill meant the probes did not go as deep as planned. The Apollo 16 attempt would fail after Duke had successfully emplaced the first probe; Young, unable to see his feet in the bulky spacesuit, pulled out and severed the cable after it wrapped around his leg. NASA managers vetoed a repair attempt due to the amount of time it would take. A HFE flew, and was deployed, on Apollo 17.
The HFE involved the drilling of two holes into the lunar surface and emplacement of thermometers which would measure how much heat was flowing from the lunar interior. This was the third attempt to emplace a HFE: the first flew on Apollo 13 and never reached the lunar surface while on Apollo 15, problems with the drill meant the probes did not go as deep as planned. The Apollo 16 attempt would fail after Duke had successfully emplaced the first probe; Young, unable to see his feet in the bulky spacesuit, pulled out and severed the cable after it wrapped around his leg. NASA managers vetoed a repair attempt due to the amount of time it would take. A HFE flew, and was deployed, on Apollo 17.