19k: A different Soviet lunar program

[septemberWaves]

The preliminary design of the N1 rocket was completed in 1962. The following year, a number of mission proposals were considered that would justify the need for the payload capacity of such a large rocket. The 19k expeditionary complex was one such proposal, and is the earliest known plan that was seriously considered for landing cosmonauts on the Moon. Information and images used in this thread are sourced from these pages: 1, 2; to clarify, the images here are modern renderings rather than original documents.

Three launches of the super-heavy N1 rocket would be required to facilitate a lunar landing with the 19k spacecraft: one for the 19k complex itself, and two for the 21k fuel tanker. The 19k complex at launch consisted of the lunar ascent stage (which also included docking equipment for the Soyuz L3 spacecraft), the variable thrust propulsion system with lunar landing and ascent structure (this stage sits below the ascent stage and includes landing equipment as well as engines and propellant for the final descent), the lunar breaking stage (which would conduct the majority of the deceleration at the Moon, excepting the final descent), the trans-lunar acceleration stage (which would conduct the lunar transfer burn), and the maneuvering tug for low Earth orbit operations (which included docking and fuel transfer equipment for the 21k tanker). Due to the lower payload capacity of the earlier N1 design, the trans-lunar acceleration stage was unfueled at launch, hence the need for the 21k tankers. It would take two tankers to fully fuel the trans-lunar acceleration stage.

The 21k fuel tankers were to be launched first, likely because they were simpler to manufacture than the 19k complex and so a launch failure would not necessarily postpone the mission by as long as a failure of the 19k complex would. These launches would serve as validation test launches for the N1 launch vehicle. Once both 21k tankers were in low Earth orbit, the 19k complex would join them; they would each dock with the 19k complex via the LEO maneuvering tug and transfer their kerosene and liquid oxygen payloads to the trans-lunar acceleration stage, before de-orbiting and burning up on re-entry.

Once the 19k complex was in low Earth orbit and fully fueled, the crew would launch in a variant Soyuz spacecraft, Soyuz L3, and dock with the 19k complex. I can't seem to find much information on this particular Soyuz variant, but it appears to at least include a lunar-range antenna on the service module. Due to the unique configuration during landing, I assume the interior of the orbital module is substantially rearranged to contain a control console for landing, as well as associated computing hardware; presumably the cosmonauts would stand upright in the orbital module during landing much like in the Apollo LEM.

The lunar portion of the mission would proceed as follows: the maneuvering tug would be jettisoned, then the trans-lunar acceleration stage would propel the spacecraft to a direct impact trajectory with the Moon; there was to be no circularization burn, much like the uncrewed landing missions of the Luna program. The lunar breaking stage would decelerate once at the moon before separating once most of the velocity towards the surface had been cancelled out, and then the variable thrust propulsion system would conduct the final descent with finer control. Once the cosmonauts had conducted whatever tasks were required on the surface of the Moon they would return to the spacecraft, and the ascent stage would separate from the lunar landing and ascent structure, carrying the crew to lunar orbit. I can't seem to find information on whether the lunar ascent stage or the Soyuz propulsion module would conduct the lunar return maneuver, but for my recreation of the mission I have opted for the latter.

I have already flight-tested my versions of all spacecraft involved in this mission profile, but have yet to conduct the actual lunar mission. This will be documented in this thread today (if all goes to plan), in several parts.

[septemberWaves]

The first 21k fuel tanker sits on the N1 launch pad at Baikonur. This will be the first flight of the N1, and the first step towards landing cosmonauts on the Moon.

The thirty NK-15 engines on the Blok-A first stage ignite successfully, and the immense rocket lifts off of the pad.

The N1 rocket passes through the lower atmosphere. The flight is nominal thus far.

Hot-staging of Blok-B engines, and separation from Blok-A.

Ignition of Blok-V and separation of Blok-B.

Fairing separation, revealing the 21k fuel tanker.

The 21k fuel tanker is placed into a low parking orbit, and its fuel cell is brought online. It separates from the final stage of the N1 rocket, which is de-orbited with a ring of solid rocket motors.

[septemberWaves]

The following day, the second 21k fuel tanker is launched.

[septemberWaves]

The time has come to launch the 19k lunar expeditionary complex. This immense payload sits atop the truly monumental N1 rocket - the third of the series to be launched. The flawless launches of the two 21k fuel tankers have allowed this far more costly launch to be given the go-ahead. Though upgrades are planned for the N1 program in future, allowing it to carry even more massive payloads with newer NK-33 engines, the 19k spacecraft complex sits at the limit of the current capabilities of this behemoth launcher.

Ignition.

And liftoff of the 19k lunar expeditionary complex.

The 19k lunar expeditionary complex is deployed to its parking orbit successfully. Here it will await the two 21k fuel tankers, and finally the crew of cosmonauts who will set foot on the Moon.

Instrumentation deployment is successful on the 19k spacecraft complex. Unfortunately, telemetry indicates that the fuel cell failed to activate, and the spacecraft batteries were drained over the following few hours. However, the 21k fuel tankers are capable of docking even in circumstances such as this where the 19k complex is unpowered, and should be able to transfer some of its power and activate an override system for the fuel cell once docked.

Spoiler

What really happened is I forgot to activate the fuel cell.

 

Edited November 30, 2020 by septemberWaves

[septemberWaves]

We return to the first 21k tanker as it prepares a sequence of maneuvers to rendezvous and dock with the 19k complex.

Unfortunately there is no good footage of the docking, as it occurred in the dark.

Once docked, the fuel transfer process occurs over a period of several hours, while the second 21k tanker prepares its own rendezvous. The 21k tanker was also able to activate the fuel cell in the maneuvering tug of the 19k complex, as predicted.

Following fuel transfer, the tanker undocks and de-orbits. It will burn up in the atmosphere.

A few orbits later, the second tanker completes its rendezvous maneuver.

This time, footage of the docking procedure is well-illuminated. Once again, fuel is transferred over the course of several hours.

The second 21k tanker undocks and de-orbits, its mission complete. The 19k lunar expeditionary complex is now ready to take cosmonauts to the Moon.

Spoiler

When I followed that tanker down through the atmosphere to get that screenshot, I wasn't expecting anything to survive, but it turns out the wide base of the spacecraft is exceptional for thermal shielding and drag, and surprisingly effective at lithobraking.

 

[KerballingSmasher]

On 11/30/2020 at 10:00 AM, septemberWaves said:

as it occurred in the dark

as is only right and proper.

[Cydonian Monk]

This entire mission profile was an absurd abomination, but I'm enjoying your approach to it and look forward to the landing!

On 12/1/2020 at 5:21 PM, KerballingSmasher said:

as is only right and proper.

Beat me to it.

[jimmymcgoochie]

On 12/1/2020 at 11:21 PM, KerballingSmasher said:

as is only right and proper.

4 hours ago, Cydonian Monk said:

Beat me to it.

And me.

(Now I remember where I saw that!)

[KerballingSmasher]

 

7 hours ago, Cydonian Monk said:

This entire mission profile was an absurd abomination, but I'm enjoying your approach to it and look forward to the landing!

Beat me to it.

Sure did! Kinda had to make the reference, what with Forgotten being "back" now!