Operation Freshman was the codename given to a British airborne operation conducted in November 1942 during World War II. It was the first British airborne operation conducted using Airspeed Horsa gliders, and its target was the Vemork Norsk Hydro hydrogen electrolysis plant in Telemark, Norway which produced heavy water as a byproduct. By 1942, the German nuclear weapons programme had come close to being able to develop a nuclear reactor, but in order for the reactor to function it would require a great deal of heavy water. The source of the heavy water was the Norsk Hydro plant, which had been occupied since 1940. When the British government learned of the German nuclear developments, it was decided that a raid would be launched to destroy the plant and deny the Germans the heavy water required to develop a nuclear weapon. Several different strategies were discussed and discarded as impractical; it was decided that a small airborne force composed of sappers from the Royal Engineer units attached to 1st Airborne Division would land by glider, a short distance from the plant, demolish it with explosives and then escape over the Norwegian border into Sweden. After an extensive training period, the airborne force took off in two aircraft–glider combinations on the night of 19 November 1942. Both the gliders and tugs were operated by aircrews attached to HQ No. 38 Wing RAF. The tugs and gliders managed to reach the Norwegian coast, but neither was able to reach their objective. The first pair suffered from navigational difficulties and severe weather, which resulted in the tow rope snapping and the first glider crash-landing, with its Halifax tug aircraft returning to base. Three airborne troops were killed outright, and the survivors were captured shortly after the crash. The second pair fared even worse, with both the aircraft and glider crashing into a mountain after the aircraft flew low in search of the first glider. Both members of the glider crew were killed outright, while the driver died soon afterwards from injuries sustained in the crash. Those who survived the crashes were captured by German forces and killed as a result of Wehrmacht's Commando Order, which stated that any Allied personnel captured while involved in commando operations were to be killed immediately. At the end of the war, the Wehrmacht personnel involved were tried, sentenced to death and executed for their part in the murders.