[sionnsar]

That means the vacuum tubes will have to have filaments, of course, and that will be a drain on the electrical system. For that reason, I think a radioactive thermionic power system would be appropriate.

Vacuum tube cathodes are often constructed with separate heater elements for purposes of reliability -- but consider that if their working environment changes dramatically their transconductance curves will also shift significantly. An analog computation that works at Venus norm might run off the rails in space-freeze.

[NicknamedBob]

Double filaments, variable voltage depending on ambient temperatures, additional insulation, and perhaps even a thermal closet to house the electronics should provide sufficient flexibility.

Keep in mind that these robots will all be designed to function as distant analogs of human operators. Another complication will involve losing line of sight communications.

This occurs for two reasons; if the robots go underground in pursuit of their attackers, or if the atmospheric station is blown away from the landing point. Each mission will be time-critical in addition to all of its other problems.