The Damned Number 125

12 April, 17:31

The Damned Number 125

To activate manual control in the Vostok spacecraft, Yuri Gagarin had to solve a logical problem.

During the first-ever manned space flight, the Vostok operated in automatic mode. However, in the case of an emergency, the pilot was supposed to enter a secret code and assume control over the spacecraft. Some say that to do so Yuri Gagarin had to solve a mathematical problem. We studied documents and memoirs of the people involved in the mission to learn whether this story is true.

On the eve of the 60th anniversary of the first manned space flight, the media buzzes with numerous materials, reviews, and interviews, and journalists try to dig up interesting facts about the mission. Many of them stumble across a popular legend: in case of an emergency, Yuri Gagarin was allegedly supposed to open an envelope with a simple mathematical problem inside. The answer to the problem was a digital code that would unlock all controls of the spacecraft for manual steering. We decided to investigate the details of this procedure and discovered that this story is nothing more than just a myth.

According to numerous articles and posts, Soviet engineers and doctors worried that the mind of the first cosmonaut could be unexpectedly affected by space flight. They had to make sure that during manual steering he would think straight, therefore, they created a kind of a captcha for him. Yuri Gagarin had to solve a mathematical problem, obtain a three-digit answer, and enter the digits into a combination lock.

A well-known public intellectual Boris Burda told this story in an interview with “Nothing of this kind had ever been done before, so the team had to consider all possible scenarios–including the one when a cosmonaut goes mad during the flight, takes control over the spacecraft, and destroys it. This is why to enter into the manual steering mode, Yuri Gagarin had to open a sealed envelope and solve a mathematical problem. A cosmonaut not in their right mind wouldn‘t be able to do that.’

To find out whether it happened, let‘s have a look at the controls and devices that Yuri Gagarin had to deal with on board. All hardware for the Vostok spacecrafts was developed at the Science and Research Institute for Aircraft Equipment (NIIAO). In 20006, the Head of Laboratory E.N. Nosov wrote about the devices and dashboards of the Vostok and Voskhod spacecrafts. His article shows that Vostok-1 and Vostok-2 (piloted by Gagarin and Titov, respectively) actually had combination locks. Namely, one can see six buttons with numbers and a slot for a coding device on the side panel of the СИС-1-3КА information display system dashboard. However, this lock was missing in other versions of Vostok spacecrafts.

This fact seems to confirm the legend about Gagarin‘s mathematical problem. However, according to Nosov, the cosmonauts received the code itself, not the problems that would produce them: ‘It is a well-known fact that the codes were passed to the cosmonauts in envelopes immediately after boarding. They were expected to open the envelopes only in dire need, namely if they had to land the spacecraft manually’.

Although Nosov was involved in the development of the ‘logical lock system’, he did not directly participate in launch preparations. Luckily, many members of the launch team left notes and memoirs about this experience. For example, Nikolay Kamanin, the head of the training program for the first cosmonauts, kept a detailed diary of the whole campaign. It was on March 13, 1961, that he first mentioned the system for assuming manual control over the spacecraft:

‘Had a meeting at the Commander-in-Chief‘s in the presence of Rudenko and Agaltsov, spent a long time discussing two issues: 1. Should we provide a cosmonaut with a code to the logical lock? Such a code would allow them to activate the manual landing system at any moment of the flight. We decided that a cosmonaut should have such a code on them.’

The team agreed on the procedure immediately before the flight. The decision to hand it to Gagarin in a sealed envelope was made during a closed meeting of the state launch commission on April 8, 1961. However, Kamanin does not mention a mathematical problem in his diary: 

‘As for the third issue (providing the cosmonaut with a code to the logical lock), the commission agreed to test the code in the spacecraft and then hand it to the pilot in a special package. Kamanin, Ivanovsky, Kerimov, and Gallay were made responsible for choosing the code and for preserving it intact both on the ground and in the spacecraft.’

Again, the diary doesn‘t contain any mentions of a mathematical task. Apparently, Gagarin was supposed to just open the envelope and read the number inside. This is confirmed by the memoirs of Mark Gallay, who was in charge of the flight training of the first cosmonauts:

‘Should the automatic piloting mode fail, a cosmonaut was supposed to open a special logical lock, i.e. to enter a sequence of three digits on a six-digit panel. Only after that, a cosmonaut could proceed with manual steering. This system was similar to modern-day house intercoms. All six first cosmonauts, including Gagarin and his backup pilot Titov, tested this scenario on a special simulator stand. I took part in these training sessions and was sure that this skill was mastered perfectly.’

According to Gallay, initially, the team planned to send the cosmonaut a radio message with the code in the case of an emergency. However, the chances of radio equipment malfunctioning were higher than that of Gagarin losing his mind. The final decision was made by Sergei Korolev, or the Chief Designer, as he was called by the launch team.

Gallay wrote about one of the meetings with Korolev: ‘Let‘s just give him this damned number in an envelope,’ - said the Chief Designer. To be honest, this decision did not seem perfect to us. With zero gravity, anything could happen. What if the envelope just floated away in the cabin, and the cosmonaut lost it? But Korolev did not want to discuss it anymore: ‘That‘s it. It‘s decided, and I‘ve already informed Moscow about it.’

According to Gallay, the envelope was attached to a panel inside the cabin, right next to the cosmonaut‘s seat: ‘Gagarin could just move a finger under the seal and break it. The envelope would open, and the number inside would become visible.’

Korolev appointed a special commission in charge of the secret code: Kamanin (the chairman), Ivanovsky (the lead designer), Gallay, and others. To make sure that the system would work, the members of the commission had to personally check the logical lock in the spacecraft. However, the participants of this process have different recollections of it. According to Kamanin, the code was 145. However, Gallay, Boris Chertok (a design engineer), and others report the number 125. Either way, immediately before the launch the system was proven effective, and the envelope was in place.

‘I squeezed the upper half of my body into the spacecraft (it was strictly forbidden to bring our feet inside!) and started to enter random combinations of digits that the chairman and the members of the commission told me. The blocking system worked perfectly! Then, I started to enter any number that came to my mind: 641, 215, 335, 146. Still, the ‘Manual Steering’ sign was dark, and the manual control system was not activated. Then I entered 125, and it came to life! As for the envelope, everything was ok with it too,” wrote Mark Gallay.

Ernest Vaskevich, a test engineer, was among the three people that performed the final check of the system. In his memoir, he wrote: “Sergey Pavlovich Korolev gave Oleg Ivanovsky, the lead designer, a small plastic bag with a coding device for the logical lock, and we went up to the top operating platform in an elevator. There, at the entrance to the spacecraft, Ivanovsky plugged the coding device into the logical lock and entered the numbers. After that we got the message from the ground: the command worked.”

It is still unclear where the myth about a mathematical problem in the envelope came from. The answer might be hidden in the name of the device: a combination lock was called a “logical” one, and therefore a code for it was called a logical code. Having heard this name, someone could have imagined a logical or mathematical problem.

In any case, the first manned space flight was successfully completed in automatic mode, and Yuri Gagarin did not have to open the envelope. But even if something went wrong, he would already know the number in it—simply because every member of the team secretly disclosed it to Gagarin before the launch. 

Later, many team members confessed to it in their memoirs. For example, Mark Gallay wrote that after the mission was over, he had a conversation with Ivanovsky: “You know, this damned number 125—I told Yuri about it. I even wrote it down, so he could remember it better. The same evening we came up with the number, I told him”. Ivanovsky, who was resting at that moment, woke up, looked at me with a strange look in his eyes, and whispered: “I told him too.”