Cryogenic Propulsion with Hydrogen-Cooled Heat Shield

A unified architecture where the same fuel cools the nozzle, shields the vehicle, and drives the future of reusable access to orbit.

Hydrogen-cooled cryogenic engine reentering Earth

Rendering: Hydrogen-cooled orbital stage reentering with regeneratively cooled heat shield

Unified Propulsion + Protection System

Gatkul’s cryogenic propulsion system leverages liquid hydrogen not only as a high-efficiency fuel but also as a working fluid for regenerative cooling during reentry. This architecture enables ultra-lightweight stages, rapid reuse, and eliminates traditional ablative thermal protection systems. Hydrogen absorbs heat at the nozzle throat, cooling the engines and shield structure before being expelled as part of the thrust stream.

Core Engineering Elements

🔥 High-Efficiency Engine: Vacuum-optimized LOX/LH₂ expander cycle with regenerative cooling jacket
🧊 Integrated TPS Cooling: Liquid hydrogen routed through shield-embedded microchannels prior to combustion
♻️ Reusable Nozzle & Shield: Cooled carbon-carbon structures sustain multiple reentries with minimal wear
💨 Vapor Layer Creation: Hydrogen boil-off forms a plasma-suppressing gas film along the shield surface
📡 Smart Flow Control: Onboard logic adjusts cooling flow dynamically based on reentry conditions

Why Hydrogen-Cooled Cryoprop?

✅ Eliminates Tiles: No fragile ablative or ceramic shields to inspect or replace
✅ One Fuel, Multiple Roles: Propulsion, cooling, and plasma flow control in one integrated system
✅ Rapid Reuse: Designed for daily or weekly reuse with minimal pad-side servicing
✅ Deep-Space Capable: Supports reentry from orbital velocity and lunar return with proper insulation

System Deployments

🛰️ PADMA Upper Stage: Hydrogen-cooled shield integrated into crew-rated orbital return stage
🧑‍🚀 LEO Shuttle Variants: Cryo-cooled heat shield tested in Trishul-class upper stages
🔄 Depot Return Systems: Cryo stages that can reenter, refuel, and redeploy

Technical Snapshot (Public)

Parameter	Value
Propellants	LOX / LH₂
Engine Cycle	Expander + Pump Fed (Vacuum Optimized)
Nozzle Cooling	Regenerative LH₂ (throat to skirt)
Shield Cooling	LH₂ through carbon-carbon microchannels
TPS Reusability	10+ reentries (target)
Vehicle Integration	Trishul, PADMA, LEO Shuttle

Development Timeline

2024: Engine test stand trials with regenerative heat rejection
2025: First flight demo using dual-use hydrogen circuit on subscale reentry shell
2026: Orbital stage integrated with H₂-cooled TPS on PADMA mission

Fueling the Future — Inside and Out

By merging propulsion and protection into a single system, Gatkul's cryogenic hydrogen architecture reduces mass, increases stage life, and simplifies reentry operations. It is a cornerstone in our journey toward aircraft-like spaceflight — clean, fast, and frequent.