While NASA and the Americans were doing their best to fulfill John F. Kennedy’s promise and go to the Moon by the end of the sixties – and possibly get back as well –, the Soviets were approaching the problem from a more practical and cheaper angle: they put away with man, and focused on the robot. When speaking of the Moon landing we usually recall the arrival of the Apollos there and almost everybody remembers Neil Armstrong’s words and steps. The Soviet Luna program – while producing remarkable results – was less successful in reaching the planet’s public. Not even us, Hungarians, who were actually involved in it – in a very exciting way.

The pearl of the program was undoubtedly the Luna 16: the first robotic probe that successfully fulfilled the mission and returned the first lunar sample. Otherwise it was the third in the row, having been preceded by Apollo 11 and Apollo 12.

The portrait of Luna 16

The space vehicle consisted of an ascent and descent stage. The latter was a cylindrical tool with four protruding legs, fuel tank, radar and a double descent engine. The main descent engine slowed down the spacecraft until the cutoff. This was determined by the onboard computer and based on the altitude and speed data. The ascent stage was a smaller cylinder with a rounded top. And there was the point: the hermetically closed sample container. The Luna 16 was also equipped with a television camera, temperature monitor, telecommunication tools and an extendable drilling rig for the collection of the lunar soil sample.

The voyage of Luna 16 was unfolding according to plans, and on 17 September 1970 it entered lunar orbit. It spent three days there, but was by no means idle: it was examining the gravitation of the Moon. Then on 20 September it started to descend on the Moon. The main descent engine cut off at the altitude of 20 meters, then at two meters it arrived with a free-fall. At the Sea of Fertility, approximately 200 meters west of the Webb crater it performed the soft landing in about six minutes. That was the point when Luna 16 already deserved to enter the history books, as this was the first Moon landing in the dark as the Sun had set about 60 hours earlier.

One hour later Luna 16 got down to work. The automatic drill reached 35 centimeters when it was stopped by harder rock. The soil sample was extracted and then placed in the container. After 26 hours and 25 minutes on the Moon, Luna 16 returned to Earth. The capsule landed on 24 September in Kazakhstan, 80 kilometers southeast of the city of Dzhezkazgan. With Luna 16 105 grams of lunar soil arrived on Earth. And now the Hungarians had an assignment.

Through the Hungarian lens

The Luna 16/078 sample arrived in a capsule at the Central Research Institute for Physics (KFKI). „They told us, here’s the lunar soil, do every test you can” – recalls László Bakos, a member of the Hungarian research team. The freedom of research was somehow restricted as the sample was not sorted geologically. The task thus could be described a little bit like an accident in the kitchen, when five types of flour get spilled and mixed and you are supposed to define the different types.

The Hungarian team undertook the task of performing the analysis of silicon and oxygen abundances in the sample with the neutron generator at work at the institute. The researchers analyzed the Mössbauer-effect on the sample as well as its REE (Rare Earth Element) content. It was essential to perform these tests without destructing the sample.

The most important reason for the arrival of the lunar soil to Hungary was the fact that at KFKI the methods used to analyze the sample were already available. Personal contact played an equally important role, that was one of the reasons the Soviets turned to Hungarian professionals. László Bakos told us that the most exciting part of the assignment was the opportunity to compare their results with the results received from other countries.

Regardless of the Cold War, the lunar samples introduced a positive element in the otherwise chilly Soviet-American relationship: the Soviets exchanged 3 grams of their lunar sample from Luna 16 for 3 grams each of the samples returned by Apollo 11 and 12.

Éva Vándor