Lunar Network Framework 🌙

Python implementation of the parametric data handling evaluation framework for autonomous lunar networks.

This repository provides an open-source Python implementation of the algorithm and case study presented in:

Rimani, J., Mascolo, L. & Fraire, J.A. "A parametric data handling evaluation framework for autonomous lunar networks." CEAS Space Journal 14, 365–376 (2022). https://doi.org/10.1007/s12567-021-00390-4

If you use this code in your research, please cite the original paper:

@article{rimani2022lunar,
  title     = {A parametric data handling evaluation framework for autonomous lunar networks},
  author    = {Rimani, Jasmine and Mascolo, Luigi and Fraire, Juan A.},
  journal   = {CEAS Space Journal},
  volume    = {14},
  pages     = {365--376},
  year      = {2022},
  publisher = {Springer},
  doi       = {10.1007/s12567-021-00390-4}
}

---

Overview

As space agencies race back to the Moon, selecting the right communication architecture for a lunar mission is critical. This framework evaluates three data-handling strategies for a lunar satellite network:

Architecture	Description
Bent-Pipe (BP)	Satellite must have simultaneous line-of-sight to the lunar site AND an Earth ground station
Store-and-Forward (S&F)	Full data volume fits within a single contact window
Store-Carry-and-Forward (SC&F)	Data is stored onboard and forwarded across multiple contact windows (DTN-style)

The framework evaluates all three over a 365-day simulation and identifies the inflection point where SC&F becomes preferable to S&F as a function of data volume D.

Case study: Marius Hills lava tube exploration

The paper applies the framework to a robotic mission to explore the Marius Hills skylight on the Moon, supported by a 6-satellite constellation and 3 DSN ground stations (Goldstone, Canberra, Madrid).

---

Installation

git clone https://github.com/JasmineRimani/lunar-network-framework.git
cd lunar-network-framework
pip install -r requirements.txt

For orbital mechanics (regenerating access windows from scratch):

pip install -r requirements.txt "astropy>=5.3" "poliastro>=0.17"

---

Quick Start

from lunar_framework import (
    LunarNetworkScheduler,
    generate_synthetic_access_windows,
    BEST_SATELLITES,
)

# Load or generate access windows
upload_windows, download_windows = generate_synthetic_access_windows(duration_days=365)

# Run the evaluation framework
scheduler = LunarNetworkScheduler(
    upload_windows=upload_windows,
    download_windows=download_windows,
    data_volume_gbit=160.0,                          # D from paper baseline
    satellite_filter=[s.name for s in BEST_SATELLITES],  # S1_0, S2_0, S3_0
    gs_filter=["Goldstone"],
)

results = scheduler.run()
print(results)
# → SimulationResults(D=160.0 Gbit | transferred=... | S&F=... (%) | SC&F=...)

---

Reproducing the Paper's Results

Run the main analysis script to regenerate Figures 5, 6, and 7 and Tables 4–6:

# Using pre-generated access windows (fastest, included in repo)
python run_analysis.py

# Using synthetic access windows (no CSV files needed)
python run_analysis.py --synthetic

# Regenerate access windows with poliastro (slow, ~30–60 min)
python run_analysis.py --regenerate

# Custom data volume sweep
python run_analysis.py --d 160 500 1000 2000 4000 8000

Output figures are saved to the outputs/ directory.

---

Repository Structure

lunar-network-framework/
│
├── lunar_framework/             # Main Python package
│   ├── __init__.py              # Public API
│   ├── config.py                # Orbital parameters (Table 2), GS coords (Table 3)
│   ├── models.py                # Data models: AccessWindow, SimulationResults, …
│   ├── scheduler.py             # Algorithm 1 & 2 – the core evaluation engine
│   ├── orbital_mechanics.py     # poliastro-based access window generation
│   ├── io.py                    # CSV I/O + synthetic window generator
│   └── plots.py                 # Reproduce Figs 5, 6, 7
│
├── data/
│   └── access_windows/
│       ├── lunar_site_access.csv        # Marius Hills ↔ satellite windows
│       └── ground_station_access.csv    # DSN ↔ satellite windows
│
├── tests/
│   └── test_framework.py        # 20 unit tests (pytest)
│
├── run_analysis.py              # End-to-end paper reproduction script
├── requirements.txt
├── setup.py
└── README.md

---

Mission Configuration

All parameters are taken directly from the paper:

Satellite Constellation (Table 2)

Satellite	a [km]	e	i [°]	Ω [°]	ν₀ [°]
S1_0	6500	0	40	0	0
S2_0	6500	0	40	0	120
S3_0	6500	0	40	0	240
S1_90	6500	0	40	90	0
S2_90	6500	0	40	90	120
S3_90	6500	0	40	90	240

DSN Ground Stations (Table 3)

Station	Lat [°]	Lon [°]	Alt [m]
Goldstone	35.4267	−116.8900	1002
Canberra	−35.4014	148.9817	688
Madrid	40.4314	−4.2481	864

Link Parameters (Section 3.2)

Parameter	Value
Payload band	X-Band
Telemetry band	S-Band
Data rate	150 Mbit/s
Compression ratio	15:1
Packet size	6400 bits
Safety factor	20 s

---

Algorithm

The evaluation framework (Section 3.3, Fig. 2 of the paper) is implemented in scheduler.py:

1. Spurious access removal – discard windows shorter than the safety threshold (Fig. 3).
2. Upload phase – for each time-sorted upload opportunity (Marius Hills → satellite), assign the satellite data and classify the upload as S&F or SC&F.
3. Algorithm 2 (bi-directional check) – test whether the loaded satellite can begin a download in the same window immediately after the upload completes.
4. Download phase – greedy search for the earliest download window; prioritises contacts that finish soonest ("reward process").
5. SC&F accumulation – if a single window is insufficient, data is carried across multiple windows until D_rem = 0.
6. Satellite recycling – once a satellite completes its download, it re-enters the eligible pool for the next upload.

---

Key Results (reproduced)

• Bent-Pipe covers less than 10% of available windows.
• The S&F → SC&F inflection point occurs at approximately 1.5 Tbit (single GS) and shifts to ~2.5 Tbit when all three DSN stations are used simultaneously.
• Satellites with RAAN = 0° consistently outperform those with RAAN = 90° in terms of GS access opportunities.

---

Access Window Generation

The original paper used STK (Systems Tool Kit) by AGI to generate satellite access windows. This repository provides two alternatives:

Option A – Pre-generated CSV files (default, fast)

Statistically calibrated synthetic access windows are included in data/access_windows/. No extra dependencies needed.

Option B – Orbital mechanics via poliastro

from lunar_framework.orbital_mechanics import generate_all_access_windows

upload_windows, download_windows = generate_all_access_windows(
    output_dir="data/access_windows",
    cadence_min=10.0,          # sampling cadence
    duration_days=365,
)

Note: Full-year computation at 10-minute cadence takes approximately 30–60 minutes. Reduce cadence_min or duration_days for faster runs.

Option C – Bring your own STK data

If you have access to STK and generate your own access reports, save them as CSV with columns: t_start_s, t_end_s, satellite, partner, partner_type

Then load with:

from lunar_framework.io import load_access_windows
windows = load_access_windows("my_stk_export.csv")

---

Running Tests

pytest tests/ -v

All 20 unit tests should pass in under 10 seconds.

---

Extending the Framework

The framework is designed to be easily adapted to new missions:

from lunar_framework import LunarNetworkScheduler
from lunar_framework.models import AccessWindow

# Custom access windows for a different mission
my_upload  = [AccessWindow(...), ...]
my_download = [AccessWindow(...), ...]

scheduler = LunarNetworkScheduler(
    upload_windows=my_upload,
    download_windows=my_download,
    data_volume_gbit=500.0,
    satellite_filter=["MySat1", "MySat2"],
    gs_filter=["MyGroundStation"],
)
results = scheduler.run()

Changing the mission simply requires providing new access windows and configuration — no code modifications needed.

---

License

MIT License. See LICENSE for details.

The original algorithm and all mission parameters are © the paper authors (Rimani, Mascolo, Fraire 2022). This Python implementation is provided for reproducibility and community use.

---

Contact

For questions about the original paper, please refer to the published article.