Research analysis

September 11, 2026 FSP hardware maturation: the 40 kW program's bench work

NASA's August 2022 Fission Surface Power project update is easy to read as program management, but its load-bearing content is bench hardware. An oscillating heat pipe panel rejecting more than 800 W on 0.5 square meters, polymer film capacitors with roughly 50 times the energy density of mil-spec parts, and a four-engine Stirling simulator rig are the kind of small items that actually gate a reactor's schedule.

September 11, 2026 Establishing a lunar surface power grid: the voltage trades

NASA Glenn's EPS-SAT study of an Artemis-scale lunar power grid reached a counterintuitive result: DC cable is lighter above 3 to 4 kV, yet the grid should be 3 kV AC, because no high-voltage radiation-hardened switches exist to build a DC bus that high. The same study prices fault tolerance in kilograms: a ring grid is about 50 percent heavier than radial, a mesh about 100 percent heavier.

September 10, 2026 NASA's Radioisotope Power Systems Program status (IECEC)

NASA's 2013 IECEC program-status paper shows radioisotope generator output on five active missions matching model predictions within roughly a watt, some 35 years after launch. Its other headline is less comfortable: the four-times-more-efficient Stirling generator had flight hardware in fabrication and still no mission to fly on.

September 10, 2026 The RPS Pool Concept: Stirling reliability by architecture

NASA and JPL engineers proposed a radioisotope generator architecture in 2015 where many Stirling convertors draw heat from one shared NaK pool, so any converter can stop while the rest pick up the load and the plutonium heat sources stay passively coolable. The concept targets 1 kWe with modular redundancy, but the record contains no test data.

September 9, 2026 Finding the volts inside a Stirling power converter

NASA Glenn engineers ran the first quantitative study of what alternator voltage a dynamic radioisotope Stirling convertor should use, modeling a two-convertor 140 W controller against real space-qualified parts. The answer, best SWaP near 45 to 63 volts rms, comes from a MOSFET resistance versus capacitor energy-density tug of war.

September 9, 2026 An RPS status paper with a supply-chain heart

A NETS 2023 status paper from the NASA/DOE Radioisotope Power Systems Program reads as routine program housekeeping, but its load-bearing facts are industrial: a refurbished legacy GPHS-RTG flight unit, a rebuild-to-print SiGe production line, constant-rate Pu-238 production, and a DRPS design that has passed review gates but not yet hardware demonstration.

September 8, 2026 Europe's americium RTG program bets on production

A NETS 2024 conference paper reports the ESA ENDURE program's progress toward flight-ready americium-241 RTGs and heater units. The constraint being engineered against is not conversion efficiency but fuel production at scale and launch safety authorization.

September 8, 2026 What 1992 got right about power electronics mass

A 1992 NASA Lewis vugraph briefing on power management and distribution technology reports PMAD mass ranging from 40 to over 220 kg/kW across existing systems. Its component-level findings on magnetics, capacitors, switches, and radiation explain why that mass has been so slow to come down.

September 7, 2026 Lunar-orbiting laser beamcraft versus the 14-day night

A NASA Glenn Compass concept study sizes a constellation of three laser beamcraft that would beam about 50 W of night power to each of eighteen small lunar landers, and trades it against batteries and radioisotopes on mass, cost, and maturity.

September 7, 2026 The ISUS thermionic PMAD and the drooping source

A 1996 NASA Lewis memorandum details the power management and distribution system designed for the Air Force ISUS thermionic-diode demonstrator, and its regulator choice still reads as the right answer for any drooping thermal power source.

September 6, 2026 Stirling convertors, qualification one g at a time

A NETS 2025 paper from NASA Glenn reports that three Technology Demonstration Convertors passed 17 years of continuous operation and that the newest Sunpower Robust Stirling Convertor survived vibration, centrifuge, and thermal-cycling qualification with sub-watt permanent power shifts. A four-convertor generator testbed reached 16.8% conversion efficiency against 6.3% for current thermoelectric RTGs, though that figure is an unoptimized baseline point, not a flight system.

September 5, 2026 A Stirling DRPS swap onto the VIPER rover

NASA's Compass team took the VIPER lunar rover design and swapped its solar-battery power train for a six-GPHS Stirling radioisotope system of about 300 We. The resulting study shows the redesign driver was not electricity but waste heat, which the generator must not dump into the ice it was sent to measure.

September 5, 2026 Fission Surface Power: what the design contracts bought

NASA's Fission Surface Power team used its IAC 2024 paper to lay out where the 40 kWe lunar reactor program actually stands. Three industry concept studies finished in 2023, a government reference design ran three design cycles, and the flight-hardware solicitation is still waiting on budget.

September 4, 2026 Deployable 40 kWe lunar fission: the honest mass bill

NASA's Compass Team designed a 40 kWe lunar fission surface power system that a repurposed pressurized-rover chassis deploys as three sled-mounted elements up to one km from crew. The architecture closes on paper, but the mass ledger lands near 10 t of power elements against a 6 t goal.

September 4, 2026 Power distribution, the 1982 SPS pacing problem

A 1982 NASA Marshall paper sized the power processing, distribution, and storage subsystem for the 5 GW space solar power reference concepts. Its verdict: the wiring and power electronics, not the solar array or the microwave tube, carried the unacceptable mass, and direct-coupled designs were the escape.

September 3, 2026 Mars surface power: dust storms set the mass winner

NASA point designs for Mars surface power compared three solar architectures against four 10 kW Kilopower reactors. For a crewed mission at Jezero Crater the solar system came in at about 9800 kg against 7000 kg for fission, a near miss driven almost entirely by surviving a 120-day dust storm.

September 3, 2026 100 kW SSP demonstrator: a modular road to gigawatts

NASA Marshall and Boeing Phantom Works sketched a 100 kW-class free-flying platform to flight-demonstrate the technologies space solar power needs: concentrator arrays, high-voltage PMAD, deployable radiators, and solar electric propulsion. The design also carries 2000 kg of payload space for wireless power transmission experiments.

September 2, 2026 Lunar fission power transmission: cables win the mass trade

A NASA Glenn Research Center trade study compared four ways to move 40 kW up to 3 km across the lunar surface: laser or microwave beaming, superconducting cable, carbon nanotube rope, and ordinary copper or aluminum conductors. Metallic conductors at kilovolt-class voltage won by an order of magnitude on mass.

September 2, 2026 Orbital laser power beaming for the lunar south pole

A NASA Langley concept-of-operations study examines beaming tunable optical power from a spacecraft in a 1,175 km near-polar lunar orbit to surface clients, so that landers and rovers survive the lunar night using their own solar arrays as receivers.

September 1, 2026 Am-241 radioisotope power for long-duration lunar rovers

The design uses four 200 Wth European Large Heat Sources and six Stirling convertors to supply a rover in permanently shadowed regions. It produces about two-thirds the power of a plutonium-238 system of similar mass, with important consequences for operations tempo.

September 1, 2026 Lunar power hibernation for low-cost solar missions

A hibernation architecture isolates the battery at dusk and uses dawn-mode power electronics to cold-start a frozen spacecraft. If the freeze-thaw cycle life holds, it could let CLPS-class missions operate for many lunar days without nuclear heat sources.

August 31, 2026 Laser-to-PV power beaming for lunar polar rovers

A 2013 NASA/Boeing preprint makes a near-term case for laser-photovoltaic wireless power transmission: beam light from a sunlit lunar mountaintop to a rover in a permanently shadowed crater and convert it to electricity.

August 31, 2026 NASA's lunar surface power grid concept

A 2023 NASA Glenn presentation lays out a lunar surface power grid that connects fission, solar, batteries, and fuel cells through local 120VDC microgrids and a modular interface converter.

August 30, 2026 Fission Surface Power TDU: measured system-level performance

A 2016 NASA test of the Fission Surface Power Technology Demonstration Unit produced 9.6 to 9.7 kW net system power at about 18.7% system efficiency, while revealing a heat-transfer bottleneck and an underperforming liquid-metal pump.