MK-52 goes to zee Moon

A project log for MK-52 Resurrect

A Programmable Calculator from the USSR!

ptravptrav 03/05/2021 at 23:430 Comments

The simulator is fully tested, (still needs the keyboard macro function). Now it can save and load files!

The installer is here:

To test the compatibility, the old LUNOLET-1 (MOONFLY-1) game has been used:

Those who can read the language, can see the original at

I probably do a shortened translation to English later. At this point, the story is about a ground technician at the Moon base in 2087, who by accident flew a tiny spacecraft (number 22, as above). The program can be loaded from

Note there are two programs: LUNOLET-1.MK52 - is the original from the magazine, LUNOLET-1B.MK52 is slightly modified to utilize the new screen with 4 lines of stack.

Back in the day, the owners of B3-34, MK-54 and MK-61 had to enter the program every time the power was cycled. The program looked like this:

The proud owners of MK-52 entered the program just once and then saved it in the memory module! So we pretend it has been entered (press A-ABT to enter FILE mode):

Select the program name with ШГ-> and <-ШГ buttons and press П->X

Here, just press F-ABT to return to the AUTO mode.

After loading, press [B/0], [C/П]; and check/enter the parameters: Moon gravity, dry mass of the MOONFLY (including 2 people in space suits), specific impulse in m/s and the maximum g-force the pilot tolerates. According to the story, the technician did not qualify for a pilot because he blackouts at 3 g.

Press [C/П] again and enter/verify the parameters: fuel mass, life support time, initial speed and altitude.

Press [C/П] again, and now you are ready to fly. Each command consists of 2 or 3 inputs: first, enter the amount of fuel to burn, press [ПП], then enter the number of seconds for the burn. If reversed thrust is not needed, just press [C/П]. For the reversed, press [ПП], followed by [/-/][C/П].

The first command was issued by the technician's son, "soon will be 12"! Entering 65, [ПП], 3 [C/П] gives us

Hit [C/П] to "wake up".

You've been in blackout for about 3.5 seconds.

According to the story, the technician tried to land the thing. The full sequence of commands in the story:

* 65 kg for 3 sec (blackout), v=+84 m/s, H=169 m (this command is already done)

* 0 kg for 2 sec (the technician climbs into the chair), v=+80 m/s, H=334 m

* 65 kg for 3 sec (blackout), v=+166 m/s, H=916 m

* 0 kg for 120 sec, v=-28 m/s, H=9175 m

* 25 kg for 2 sec, v=+5 m/s, H=9151 m

* 10 kg for 10 sec (reversed thrust, use /-/), v=-26 m/s, H=9044 m

* 25 kg for 5 sec, v=+3 m/s, H=8984 m

* 0 kg for 90 sec, v=-143 m/s, H=2652 m

* 100 kg for 3 sec (blackout), v=-31 m/s, H=2123 m

* 10 kg for 20 sec, v=-49 m/s, H=1314 m

* 10 kg for 15 sec, v=-57 m/s, H=515 m

* 35 kg for 1.5 sec (blackout), v=-17 m/s, H=390 m

* 22 kg for 22 sec, v=-17.5 m/s, H=13.5 m

* 22 kg for 0.7 sec (blackout), v=-17 m/s, H=7 m (this was a panic press)

* 22 kg for 0.7 sec (blackout), and:

The MOONFLY ran out of fuel (press C/П), but still landed with some reasonable speed of 3.6 m/s: