# Yenisei (rocket)

Yenisei (Russian: Енисей), project name RN STK-1 (Raketa-Nositel' SverkhTyazhologo Klassa - Carrier rocket super-heavy class), is a super-heavy launch vehicle being developed by the Russian space industry. The main developer is RSC Energia.
It is being developed within the framework of the federal target program "Creation of a super-heavy class space rocket complex". The program was given a budget of 600 billion rubles (USD ~$6 billion). It is the main rocket of the Russian Lunar program.
The final design for the rocket was expected to be complete by autumn 2021, but the program appears to have been paused or stopped just before this expected completion date.
In 2024, it was announced that the project will resume in 2025.
The first launch was expected to happen in 2033 from the Vostochny cosmodrome.
Based on the Yenisei launch vehicle, the Don launch vehicle (RN STK-2) is being developed by adding another stage.

## Development

The rocket got its name at the end of 2018, before that it was called "RN STK" (super-heavy launch vehicle).

### Chronology of development.

| Event | Date |
| Start of work on the creation of the RD-171MV engine | June 2017 |
| Start of research work on RD-0150 engine | June 2017 |
| Preliminary estimate of the cost of R&D on the RN STK | October 2017 |
| Decree of the President of the Russian Federation on the creation of the RN STK | January 2018 |
| Official name for RN STK | January 2019 |
| Feasibility study of the RN STK project | Spring 2019 |
| Draft design | 2018–2019 |
| R&D, design, and construction works | 2020–2028 |
| Flight tests | from 2028 |

## Planned events

* October 2021 – end of technical design.
* 2026–2028 – construction and commissioning of infrastructure for a super-heavy launch vehicle and a medium-class rocket for launching crewed spacecraft from the Vostochny cosmodrome.

## Design

The first stage will consist of 6 blocks, each block will be based on the first stage of the planned Irtysh / Soyuz-5 rocket with an RD-171MV engine.
The second stage will consist of one block – matching the first stage of Soyuz-6 – with RD-180 as engine.
The upper stage will be KVTK.
Accelerating braking unit: Block DM

### Proposed variants

| Name of a rocket | Yenisei | Don |
| Type | Stage one | Stage two |
| First launch | 2028 | 2032–2035 |
| First stage | 6xRD-171MV | 6xRD-171MV |
| Second stage | RD-180 | RD-180 |
| Third stage | - | 2×RD-0150 |
| Upper stage | KVTK, 2×RD-0146 | KVTK, 2×RD-0146 |
| Accelerating braking unit | DM, 11D58MF | DM, 11D58MF |
| Height (max.) | | |
| Launch weight, t | 3167 | 3281 |
| Thrust (at ground level) | | |
| Thrust-to-weight ratio | | |
| Payload (LEO 200 km), t | 103 | 140 |
| Payload (GTO 5500 km), t | | |
| Payload (GEO 35,786 km), t | 26 | 29.5 |
| Payload to TLI, t | 27 | 33 |

## Flight tests

Flight tests of a super-heavy launch vehicle will take place in two stages from 2028 to 2035.
The first stage of testing will take place in 2028–2032. It involves the launch of a crewed spacecraft, a lunar take-off and landing complex (LVPK) and other payloads on the trajectory of the flight around the Moon and circumlunar orbits in order to work out the elements of a crewed complex, create a station in the orbit of the Moon, and land on the lunar surface.
The second stage of testing will take place in 2032–2035. It is planned to launch LVPK and other uncrewed payloads for the construction and operation of a base on the lunar surface. In addition, this stage involves participation in international programs related to the study of Mars.

## Applications

The super-heavy rocket is supposed to be used in the Russian lunar program, since the carrying capacity of the Angara-A5V launch vehicle (37.5 tons to LEO) is insufficient for these purposes.

### Lunar program payloads

* 20-ton Orel spacecraft.
* 27-ton lunar landing and takeoff complex (LPVK).
* 32-ton lunar base module.

### Satellite constellation

* Spacecraft up to 30 tons to geostationary orbit
* Space telescopes 30–40 tons to the L2 Lagrange point in the Sun-Earth system