Ground Control to Major Tom: Eavesdropping on Orbit

My HackSpaceCon 2026 talk on the (in)security of the protocols holding low-earth orbit together AX.25, CCSDS, and DVB-S2. Full slide deck embedded.

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Presented at HackSpaceCon 2026 — Cocoa Beach, FL.

Unfortunately the recording equipment wasn't working, so there's no video — but here are the slides. This talk breaks down three of the protocols holding low-earth orbit together — AX.25, CCSDS, and DVB-S/S2 — and shows how little stands between an antenna and the data.

▶ Open the slides fullscreen

Navigate with ← / → (or the on-screen arrows); press R to jump back to the first slide.

What it covers#

  • AX.25 — the amateur backbone flying on the ISS and hundreds of CubeSats, with zero cryptographic defenses (partly by regulation).
  • CCSDS — the professional stack (NASA / ESA / JAXA). A security overlay, SDLS, exists — but adoption is glacial and most missions still ship without it.
  • DVB-S / S2 — the commercial workhorse behind satellite TV, VSAT and backhaul. Researchers intercepted live traffic with ~€300 of consumer gear.
  • Viasat / KA-SAT — proof this isn't theoretical: tens of thousands of modems knocked offline through a ground-segment compromise on the first morning of the 2022 invasion of Ukraine.

The takeaway#

Passive reception has become cheap for whole classes of satellite traffic, active RF attacks are harder (and often illegal), and ground-segment compromise remains the most realistic high-impact path. The ground is in 2026; orbit is still in 1996.