Data is costly or absent
Where mobile data is metered or towers are far, a shared offline cache can serve an entire classroom from one hub.
Nexus 0.3 live — multi-node fabric, collaborators welcome
From orbit to offline knowledge — then across the village mesh for communities left behind
SkyCache Nexus is an open-source, receive-only knowledge fabric: public free-to-air satellite signals and offline education packs become a local library for schools, clinics, and villages — with multi-node unlicensed Wi-Fi mesh, store-and-forward updates, and zero commercial satellite decryption.
Honest scope: store-and-forward knowledge + community mesh — not free Starlink-style internet.
The problem
Connectivity is not the same as information access
Hundreds of millions of people still face expensive or unreliable data, intermittent power, and few local libraries. Commercial satellite broadband can transform some regions — but it is not free, not available everywhere, and not always the right tool for a school that needs textbooks and health flyers more than video streaming.
Commercial satellite is not universal
Paid constellations require kits, subscriptions, and policy access. Many communities simply cannot start there.
Knowledge packs already exist
Kiwix, Internet-in-a-Box, and RACHEL prove offline education works. SkyCache adds a lawful satellite + prioritization path on top.
We avoid fabricated statistics. The digital information divide is real; SkyCache addresses a practical slice of it.
The solution
SkyCache Nexus: knowledge hub + community fabric
Receive open satellite products (and USB education packages), organize them with humanitarian priorities, replicate across a village mesh, and serve ordinary phones over local Wi-Fi — resilient, solar-friendly, and community-owned.
Offline-first knowledge
Phones connect to a local WiFi portal — no mobile data required to read cached education, health, weather, and emergency guides.
Ultra-low-cost hardware
Built around RTL-SDR dongles, Raspberry Pi–class boards, and simple antennas. Starter kits target roughly $90–200 before solar.
Open source by design
Apache-2.0 software, modular decoder plugins, and documentation written for technical volunteers and trained local maintainers.
Legal & ethical rails
Receive-only. Unencrypted free-to-air and openly licensed content only. No commercial constellation decryption — ever.
Community-owned
Designed so a village school or clinic can operate the hub after training — not a black-box service that vanishes with a subscription.
Honest about limits
Store-and-forward information access. Not free Starlink. Not bidirectional broadband. Useful where that honesty matters most.
How it works
From sky signal to classroom phone
A modular pipeline — not a black box. Simulation mode lets you demo the entire portal before a single antenna is raised.
- 01
Public satellite signal
Free-to-air weather imagery and open amateur telemetry — never encrypted commercial broadband.
- 02
Low-cost SDR receiver
RTL-SDR or SoapySDR-compatible hardware with a simple antenna or modified FTA dish.
- 03
Decode & prioritize
Wrap mature tools (SatDump, gr-satellites). Rank emergency, health, and education first when storage is tight.
- 04
Local content cache
SQLite catalog + filesystem packages. Simulation mode works with sample content before any live pass.
- 05
Wi-Fi mesh fabric (Nexus)
hostapd hotspot plus multi-node mesh, DTN store-and-forward, and opportunistic open gateway pulls under daily quotas.
- 06
Phones in the community
Mobile-first PWA with large icons, multi-language UI, mesh status, and clear freshness stamps on every item.
Content prioritization
When storage or power is scarce, SkyCache keeps what matters most:
1. Emergency2. Health3. Education4. Agriculture5. Weather6. Maps7. General8. Raw telemetry
Technology
Architecture at a glance
Python core, FastAPI portal, SQLite catalog, decoder plugins wrapping SatDump and gr-satellites — built to extend as open signal sources evolve.
Loading diagram…
Modular decoders
Plugin contract for FTA weather, open amateur telemetry, and file/ZIM import. Forbidden commercial decrypt sources are rejected in config.
Offline-first portal
Mobile PWA with multi-language UI, captive-portal redirects, and admin views for storage, power mode, and content status.
Simulation day-one
skycache serve --sim loads sample packages so NGOs and teachers can evaluate the experience without RF gear.
Hardware & cost
Starter kits in the $90–200 range
Approximate 2026 street prices — verify locally. Solar is optional for first demos; LiFePO4 kits enable night operation for village hubs.
RTL-SDR dongle
$25–40Blog V3/V4 or quality clone; SoapySDR-friendly
SBC or used mini PC
$35–80Raspberry Pi 4/5, Orange Pi, or a used laptop
Storage
$10–2564–128 GB microSD or USB SSD
VHF antenna (DIY OK)
$5–30V-dipole or QFH for ~137 MHz weather paths
WiFi AP (if needed)
$10–20USB adapter when onboard AP is unreliable
Solar kit (optional)
$150–30040–100 W panel, LiFePO4, controller — village nights
Advanced L-band weather (e.g. GOES HRIT) needs dish + LNA and is Phase 2+ only. VHF weather or pure USB/Kiwix content already delivers value.
Roadmap
MVP phases
- Phase 0Live
Simulation / demo
Run the portal with sample packages — no satellite hardware required. Ideal for demos and training.
- Phase 1Live
Recorded data → portal
Ingest files, ZIM/education packs, USB drop watch, and hotspot install scripts for Raspberry Pi / Debian.
- Phase 2In progress
Live open reception
FTA weather via SatDump + RTL-SDR wrappers, with admin signal hooks and legal source rails.
- Phase 3Live
Prioritization & ops
Priority classes, power modes, community notes, package tools, local maintainer training.
- Phase 4Live (0.3)
Nexus fabric
Multi-node mesh, DTN, content fabric, opportunistic gateway, disaster mode, village playbooks.
Legal, ethical & open principles
Trust through transparency
SkyCache is a humanitarian technology project. Capability without ethics is not a feature.
- Receive-only by default — no satellite uplink in the core product.
- Unencrypted free-to-air, public, or openly licensed content only.
- Never reverse-engineer or decrypt commercial satellite internet (Starlink, OneWeb, paid VSAT, etc.).
- Operators must verify local spectrum and WiFi hotspot regulations before deployment.
- Health content is educational — not diagnosis or prescription.
- Prefer local capacity building, repairable hardware, and solar-aware power modes.
Get involved
Three doors — same mission.
FAQ
- Is SkyCache free Starlink / satellite internet?
- No. SkyCache is receive-only store-and-forward knowledge plus optional unlicensed community mesh. It caches public free-to-air signals and offline education packs for a local Wi-Fi portal. It does not provide bidirectional commercial broadband or decrypt paid services.
- What hardware do I need?
- A starter kit is roughly $90–200: RTL-SDR, a small single-board computer or used laptop, storage, and a simple antenna. Multi-node Nexus fabrics add cheap APs or extra Pis. Solar is optional for first demos.
- Is it legal?
- SkyCache only targets unencrypted free-to-air or openly licensed content. Mesh transmit is unlicensed/ISM Wi-Fi only. Operators must check national spectrum and hotspot rules. Never use it to access paid encrypted constellations.
- Can I try it without a satellite?
- Yes. Simulation mode loads sample packages; `skycache nexus sim` exercises multi-node fabric with zero RF hardware.
Contact
Questions, contribution ideas, partnership notes, or deployment interest — mail [email protected] (forwarded to the maintainers) or use the form. [email protected]
- Contribute — code, docs, translations, field testing
- Deploy — NGO or community pilot interest
- Partner — aligned offline-education or open-radio projects