Artist impression of nuclear-powered spacecraft near Mars

As humans prepare to explore farther from our Sun with more cargo and more versatility, our current space technology is quickly reaching its limits. Nuclear-electric propulsion could provide a large source of power that solar panels or traditional propellants cannot achieve.

The “Rocketroll” study (a loose acronym taking letters from the phrase “pReliminary eurOpean reCKon on nuclEar elecTric pROpuLsion for space appLications”) tasked three consortia to investigate a European approach to nuclear electric propulsion. The study is similar to the Alumni study but focusses on electric propulsion instead of nuclear-thermal propulsion. With nuclear-electric power, controlled fission is used to generate electricity.

The Rocketroll study was conducted because some space missions have high-power requirements which can only be achieved with nuclear power. For example missions to outer planets, or Moon surface missions that need to survive the 14-day lunar night. The Rocketroll designs could provide electrical power ranging from hundreds of kilowatts that would fit with Europe's Ariane 6 heavy-lift rocket, to a few megawatts that could be launched on next-generation rockets.

Three teams looked at the nuclear-electric designs and proposed their solutions in three reports, the executive summaries are public and are linked below.

Tractebel led a proposal that relied on enriched uranium, CNRS proposed a solution based on a molten salt reactor, and OHB Czech Space suggested a larger spacecraft.