A satellite goes dark over Europe. Solar panels knocked offline by a cyber hit or a rival’s laser. No power for critical systems. Game over for that billion-dollar asset.
Latvian startup Deep Space Energy says the fix is sitting in the byproducts of existing nuclear storage right now.
Their radioisotope generator, built around a radically simplified Stirling engine, turns heat from Americium-241 into electricity with five times less fuel than the old NASA-style RTGs (thermos-electric generators). The military payoff is a backup power source that keeps high-value Geostationary Orbit (GEO) and Highly Elliptical Orbit (HEO) satellites alive when the sun disappears or gets jammed. Looking beyond that is the moon: Rovers that can actually survive the two-week lunar night instead of dying after 14 days.
Military.com spoke with CEO Mihails Ščepanskis fresh off the company’s €930K pre-seed close. Here’s what he laid out.
Riga Startup - Deep Space Energy
Ščepanskis holds a PhD in physics. He built CENOS, an international simulation software company. Recently he stepped down as CEO there to chase something bigger.
“The initial idea was just to build a better converter for radioisotope power systems,” he told Military.com.
We wanted to focus on heat-to-electricity conversion that’s more efficient. It started for deep science missions, but very quickly it evolved into the lunar economy. And very recently we realized our product might be beneficial for strategic satellites.
That pivot caught NATO’s eye. Deep Space Energy became the first Latvian company accepted into the NATO DIANA accelerator. The validation opened doors (and funding) fast.
The Stirling Trick That Changes Everything
Here’s the simple version: Take Americium-241, a radioisotope extractable from nuclear waste, stick it in the middle of the unit. It decays and gives off heat. That heat makes pressurized helium gas oscillate. The gas pushes a single piston with permanent magnets through AC coils. Electricity comes out.
Traditional RTGs are thermoelectric and top out at 5-6% efficiency. This dynamic system hits roughly 25%. Result: five times less fuel for the same power.
“Why that’s important is because the limitation of production of radioisotopes actually constrains all future lunar exploration,” Ščepanskis said. He continued:
With RTG you can only power small missions. Five times more efficient means we can power five missions instead of one.
For satellites, that efficiency also means a lighter, more reliable backup that doesn’t need maintenance in orbit.
Russia and China Made This Urgent
Ščepanskis is plugged into NATO DIANA’s threat assessments. And the message is blunt: it’s not a matter of if adversaries target strategic satellites, it’s when.
Military planners have already seen it in Ukraine. Ground operations run on satellite intelligence. A cyberattack that disrupts solar power harvesting can starve a satellite of energy and lead to total loss. Laser attacks from rival spacecraft are also a concern. Even simple close-proximity spying forces satellites to maneuver, burning power at the worst possible time; such as during eclipse when solar arrays are useless.
Ščepanskis explained Deep Space Energy’s role:
We provide resilient power to backup the most critical subsystems of the satellite to prevent its loss. And second, we can provide energy independent from sun for limited pulses of electric propulsion to help satellites maneuver.
The assets? High-value GEO and HEO satellites laregely; GEOINT, SIGINT, early-warning, and synthetic aperture radar platforms. Not the smaller and more prevalent Low Earth Orbit (LEO) constellations. The ones Europe and America have too few of and can’t afford to lose.
Lunar Night Survival Is the Same Tech, Different Problem
On orbit, satellites deal with 50-minute eclipses. On the Moon it’s two straight weeks of darkness and temperatures that drop below -150°C. Current rovers die after about 14 days. That makes lunar ops insanely expensive; especially to have your asset offline half the time.
The same compact generator lets rovers and surface gear keep limited systems running through the long night and in permanently shadowed craters. Suddenly you’re not racing the clock, but rather building a real presence that can last.
€930K in the Bank — Here’s What Comes Next
€350K from Outlast Fund and angel investor Linas Sargautis plus €580K in ESA, NATO DIANA and Latvian government contracts are helping to fund the next engineering push.
The business plan still centers on the lunar economy, but defense applications for resilient strategic satellites are now front and center. The next big milestone will be in 2029 with an electrically-heated in-orbit demonstration. Actual radioisotope fuel will follow, hopefully by 2032, once supply catches up.
The Bottleneck Everyone’s Watching
Supply chain for Americium-241 is the real limiter. Extracting it from nuclear waste takes serious capital and specialized facilities. But Ščepanskis flips the problem into an advantage:
“Supply chain limitation is a bottleneck and a challenge,” he said.
But we see that as a competitive advantage since we are five times more efficient. It increases our chance to make product out of this even with a limited supply.
Bottom Line for Defense Planners
Deep Space Energy is waking up space planners to the fact that they can’t keep depending on legacy power models for every watt in orbit. A small team in Riga just handed NATO and ESA a practical way to harden the satellites that matter most; while also potentially unlocking serious lunar operations.
Nuclear waste powering military satellites and Moon bases. Sounds like sci-fi until you realize the physics checks out and the first flight hardware is already on the drawing board.
Watch this space. Literally.
