NASA's Orbilander mission will search for alien life on Saturn's moon 'Enceladus'

NASA’s Orbilander mission is being redesigned to probe Enceladus, one of the moons of Saturn known for its subsurface ocean and icy plumes. This updated mission is scheduled for a 2038 launch, targeting evidence of alien life beyond Earth by sampling material ejected from the moon’s cryovolcanic eruptions.

Enceladus is characterised by plumes of water vapour that burst through cracks in its ice shell, driven by tidal forces flexing its interior. Scientists are of the belief that these plumes provide a practical way to analyse the moon’s hidden ocean without drilling, offering potential insights into its habitability.

Originally a dual-component orbiter and lander, the Orbilander will now begin with multiple plume flybys before lowering its orbit to 31 miles for a year-long scouting phase. A lander will then touch down for a two-year mission to study the icy crust and refrozen plume material in depth.

Given Enceladus’s distance from the Sun, solar panels are ineffective. Instead, the spacecraft will use a Radioisotope Thermoelectric Generator (RTG) for power—technology previously deployed in missions like Mars Curiosity. It will also rely on cold gas bipropellant thrusters for accurate manoeuvring.

The Orbilander will require just one RTG, unlike Cassini’s three, and the overall spacecraft mass has been reduced by 1,865 pounds. These design changes are expected to cut around $900 million in mission costs, while enhancing energy efficiency and launch-readiness. This technology, already proven in other missions like Mars Curiosity and Galileo, will provide the power needed for the spacecraft to complete its complex mission.

In case of funding issues, NASA has proposed a backup plan to continue the mission in a more limited form. A contingency plan involves a flyby-only mission, collecting data during high-speed passes. However, this would include fewer instruments and risk degrading biological samples, limiting the scope of scientific analysis.

The Orbilander was ranked as the second-highest planetary science priority by the National Academies' 2023–2032 Decadal Survey. Scientists emphasise that studying Enceladus may not only reveal possible life but also help understand why it does not form in some habitable settings.