---
title: "Mru documentation"
url: https://docs.mru.space/
description: "Reference for Mru's open core: the quorum decision crate, the fault-injection demo, the Dusk simulator and Mru 2049. Apache 2.0."
---

Overview

# Mru documentation

Reference for Mru's open core: the shrinking-quorum runtime, the Dusk simulator, and the tools around them.

Status: Early. The runtime is a prototype at TRL 3, and its API will change. All code here is open source under Apache 2.0. Mru 2049's bundled data keeps its own licences.

## Where to start

[

Concepts

### Degradation-first design

The Degradation-First Principle, the shrinking quorum, and how we score a system that is always losing parts.

](https://docs.mru.space/concepts/shrinking-quorum/)[

Core runtime

### The `quorum` crate

Vote on three, compare on two, self-check on one. `no_std`, no allocation, checked with Kani.

](https://docs.mru.space/core/quorum-crate/)[

Simulation

### Dusk

A Monte Carlo of redundancy policies on hardware that only ever decays. 10,000 missions in about two seconds.

](https://docs.mru.space/simulation/dusk/)[

Integrations

### F´ and OPS-SAT

The plan for F´ components around the Rust core, and the operations note for running on OPS-SAT.

](https://docs.mru.space/core/quorum-cli/)[

Lab

### Mru 2049

A browser flight simulator on real astronomical data. 109,389 stars, planets correct for any date.

](https://docs.mru.space/lab/2049/)

## Quickstart

You need a Rust toolchain. Clone the runtime, run its tests, then run the demo with a stuck replica and a dead one.

```
# the runtime and its demo
git clone https://github.com/mruspace/flight
cd flight
cargo test --workspace
cargo run --release -- --policy shrink --ticks 20000 --seed 1 \
  --upset-rate 0.001 --fault stuck:1@4000 --fault kill:0@9000
```

Run the same seed with `--policy tmr` to compare:

```
quorum --policy tmr    ...  useful=8993  detected=11007 wrong=0 halted_at=never
quorum --policy shrink ...  useful=14490 detected=10    wrong=0 halted_at=never
```

Then the simulator, which needs no dependencies:

```
git clone https://github.com/mruspace/dusk
cd dusk
cargo run --release              # 10,000 missions, about 2 s
cargo run --release -- --sweep   # sensitivity, about 30 s
```

## Where the code lives

| Repository | What it is | Language | Status |
| --- | --- | --- | --- |
| [mruspace/flight](https://github.com/mruspace/flight) | Decision core and demo program | Rust | v0.1.1 · TRL 3 |
| [mruspace/dusk](https://github.com/mruspace/dusk) | Redundancy Monte Carlo | Rust | 0.1.0 · TRL 3–4 |
| [mruspace/2049](https://github.com/mruspace/2049) | Browser flight simulator | TypeScript | Lab |

Code Apache 2.0 · Whitepaper CC BY 4.0, doi:10.5281/zenodo.20579438 · Questions: [Request information](https://mru.space/contact/)