The data picked lithium-ion in 2000. Four years later, Airbus built the first geostationary satellite to fly on it.
A satellite runs on sunlight, and on a battery whenever it passes into Earth’s shadow. Nickel-cadmium was the first rechargeable satellite battery. Nickel-hydrogen, nickel paired with hydrogen gas in a sealed steel vessel, lasted longer and became the standard. Lithium-ion is the chemistry in phones and laptops, adapted for space. For each one we measured how much better per dollar it got each year, using only the patents published at the time.
% better per dollar each year. Readings every two years. The lithium-ion line starts in 2000: its first space patents appear in 1999.
In 2000, the first year it can be read, lithium-ion was getting about 41% better per dollar every year, nickel-hydrogen about 23%. Lithium-ion stayed ahead at every reading since. Nickel-hydrogen’s rate had been falling since the late 1980s: a battery that had done most of its improving.
Lithium-ion stores the same energy in far less mass. On W3A it saved about 200 kg, mass that goes to payload or a cheaper launch. Orbital put the battery saving at 30 to 50% when it switched in 2005.
Our data: lithium-ion improving about 1.8 times as fast as nickel-hydrogen.
ESA’s Proba-1 flies the first lithium-ion battery in space.
Eutelsat W3A, built by Astrium (now Airbus), is the first geostationary satellite on lithium-ion.
Orbital switches its communications satellites to lithium-ion.
Boeing orders lithium-ion batteries for two satellites.
Saft’s lithium-ion batteries fly on their 100th satellite.
ESA: lithium-ion has “entirely supplanted” earlier batteries in space.
It would not have said which cell maker to back, or when lithium-ion would be judged safe to fly. It would have said the next satellite battery would be lithium-ion, four years before the first geostationary satellite flew on it.
For a satellite builder, that meant about 200 kg back on every satellite. Airbus moved first, and by 2019 had flown lithium-ion on more than 60 Eurostar satellites.
The same reading works for the choice you are weighing now.
TIR — the Technology Improvement Rate — measures how fast a technology gets better each year, computed from global patent data. Not who is filing, or how much: how fast the route is actually moving. Historically, the fastest-improving technology always wins.
Provenance. Every patent carries a publication date, so the record can be replayed: every improvement rate on this page uses only the patents that were published at the time. Chart data: GetFocus platform exports, October 2026.
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