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AEXONLAB · NUCLEAR THERMAL PROPULSION STARTUP

PROPULSION BUILT FOR DEEP ORBIT SMALLSATS

Aexonlab is an early-stage startup designing solid-core nuclear thermal engines for 100–500 kg spacecraft — targeting roughly double the specific impulse of hydrazine, at thrust levels electric propulsion can't reach.

Explore the engine See the numbers
Design Isp0 s
Thrust class50–400 N
Core temp.0 K
Engine mass<0 kg

REVOLUTIONIZING SMALLSAT PROPULSION

THE REACTOR IS THE ENGINE

A chemical thruster is capped by the energy locked in its propellant's molecules. Aexonlab's engine heats liquid hydrogen with fission heat instead — reaching exhaust velocities no combustion reaction can match, through fuel channels running at 2,700 K.

Aexonlab nuclear thermal engine schematic Liquid hydrogen flows from the propellant tank through a turbopump into the reactor core, heated from 20 kelvin to 2700 kelvin by fission, then expands through a converging-diverging nozzle as thrust. LH2 TANK · 20K PUMP TURBOPUMP REACTOR CORE · 2,700K C–D NOZZLE THRUST

LH2 tank → turbopump → reactor fuel channels → C–D nozzle → exhaust.

UNMATCHED FOR ITS CLASS

CHEMICAL THRUST. NEAR-ELECTRIC EFFICIENCY.

Figures below are per-mission design targets for a 200 kg-class spacecraft executing a 500 m/s orbit-raise.

0sDesign Isp
50–400NThrust class
~0minBurn for 500 m/s
0KCore temperature
HYDRAZINE230 s
AEXONLAB NTP880 s
HALL-EFFECT1,600 s
500 M/S ΔV MANEUVER · 200 KG-CLASS SPACECRAFT
MetricHydrazineHall-effectAexonlab NTP
Thrust5–20 N40–80 mN50–400 N
Burn time, 500 m/s≈ 6 min≈ 3–5 weeks≈ 8–12 min
PropellantN₂H₄XenonLH₂
Propellant mass≈ 45 kg≈ 6 kg≈ 12 kg
Engine module mass≈ 18 kg≈ 12 kg≈ 95 kg (target)

ENGINEERED FOR THE MANEUVER, NOT THE MONTH

RAISE ORBIT IN MINUTES, NOT WEEKS

A conjunction warning doesn't wait for a slow electric spiral. At chemical-class thrust, Aexonlab's engine completes a 500 m/s orbit raise in a single short burn window — then relights for the next one.

Orbit-raise maneuver diagram A satellite fires its engine while orbiting a planet on an elliptical path, raising from a smaller dashed orbit to a larger active orbit. EARTH ORBIT RAISE · 500 M/S

Continuous-thrust orbit raise from a low starting orbit (dashed) to mission orbit.

SAFE BY DESIGN

DESIGNED AROUND THE SAFETY REVIEW

Every legacy NTP program — NERVA, Rover, DRACO — had to answer the same question before it flew. Aexonlab designs the answer in from the first fuel-element drawing.

  • Sub-critical through ascentControl drums held at launch configuration keep the core at keff ≈ 0.95 — no self-sustaining fission reaction is possible during launch, ascent, or any credible abort scenario.
  • Nuclear & launch safety reviewDesign work targets compliance with national nuclear licensing and launch safety clearance requirements for nuclear-powered spacecraft, planned alongside hardware milestones.
  • Minimal radioactive inventoryA smallsat-scale core carries a small fraction of the fissile inventory of a terrestrial power reactor, by design.
  • High-orbit disposalMission planning targets end-of-life disposal in a long-lived storage orbit, consistent with orbital debris and nuclear safety guidance.

TEST PROGRAM

FROM REACTOR SIMULATION TO ORBITAL DEMO

PH-02025–26

Reactor design & simulation

Neutronics and thermal-hydraulic modeling of the fuel-element geometry and core layout, ahead of any physical hardware.

PH-12026–27

Cold-flow bench

Pump, feed system and nozzle validated with unheated LH₂ on a ground test stand.

PH-22027–28

Electric core simulator

Fuel-element thermal-hydraulics tested with resistive heating, no fissile material.

PH-32028–29

Critical assembly

Low-power criticality testing planned at a licensed government test facility.

PH-42030

Orbital demonstration

Targeting a first in-space firing on a rideshare-launched technology demonstrator.

JOIN US

HELP US DESIGN THE FIRST ENGINE

Aexonlab is a small, early-stage team working toward our first ground test. If you want to help design a nuclear engine from a blank sheet — not maintain one that already flies — we want to hear from you. We don't have a public job board yet; write to us directly.

Reactor & nuclear engineering

Core physics, fuel-element design, criticality and shielding.

Propulsion & fluid systems

Cryogenic feed systems, turbopumps, nozzle and thermal design.

Structures & systems integration

Vehicle interfaces, thermal management, ground test hardware.

Safety & regulatory affairs

Nuclear licensing pathways and launch safety case development.

Get in touch Select “Careers” as the inquiry type and tell us where you'd fit.

GET IN TOUCH

BUILDING A MISSION THAT NEEDS ΔV, NOT PATIENCE?

Tell us about your spacecraft, your orbit, and your timeline. Partnership, investment and press inquiries all reach the same inbox — we read every one.

Aexonlab HQ
LocationBengaluru, Karnataka, India
Coords12.9716°N, 77.5946°E
Emailcontact@aexonlab.com
ResponseWithin 2 business days · IST (UTC+5:30)
Sent straight to our inbox, resume included