It's what it sounds like: Given the output of the NASA nuclear reactor (the one they're going to use for the Artemis program), and the use of an electric-motor-driven turbine system, how feasible is a nuclear-thermal aircraft for long-term studies of Titan's surface and lake system. Please edit if you have something to add! (:
It's absolutely impractical. Source: https://en.wikipedia.org/wiki/Kilopower
- 1 kWe Kilopower reactor weighs 134 kg
- 10 kWe Kilopower is expected to mass 1500 kg
The Artemis nuclear reactor would be 40 kWe, so we can reasonably assume it would be weight over 6000kg.
We don't have any current or planned rocket capable of delivering these kinds of spacecrafts.
A very quick calculation to see if the concept of nuclear airplanes on titan is viable would be, using a simplified version of this aircraft as a reference:
A 5000kg aircraft can fly on earth with 500kw.
About 10 times the thrust to power provided by our reactor, without even any payload or plane components. However, Titan's gravity is only 14% times that of our planet.
So the orders of magnitude kind of checks out, but it would be challenging, and gaining a comparative advantages vs a blimp might be even harder.
Take my answer with a grain of salt: the reference reactor are meant to work in a vacuum, they are absolutely not meant for Titan's environment
As Antzi correctly identifies, doing this via nuclear decay->heat->boiling fluid->turbine->electricity->electric motors->propellers is pretty marginal. In terms of serious engineering we have Dragonfly, which is designed to fly on an RTG but only for short battery assisted periods. A kilopower design would probably be similar in 'can fly but not forever'. Edit: seems we have proposing an RTG powered aircraft able to fly for entire life of mission, if somewhat marginally.
If we bypass the 'like kilopower' then we get the nuclear powered bomber and missile programs designed to use nuclear heat to directly generate thrust. While unclear if any actually flew under own power, their existence suggest flight on earth is considered achievable. In a lower gravity and with a colder working fluid on Titan generally similar designs would presumably also work.
There are two main things that make this possible: High Air Density and Low Gravity.
Lift force increases linearly with air density. Since Titan has 4 times the air density of Earth, lift is 4x as strong for a given airspeed.
Since Titan's gravity is 14% of Earth's, we only need 14% of the lift required on Earth to counteract it.
Overall, this means our required thrust is much lower than on Earth - roughly 14% / 4 = 3%.
Smaller is Fine
The Cessna's engine weighs 117 kg, the max loaded weight is about 350 kg greater than the dry weight, so we need our power plant to weigh less than 460 kg in order to just fork lift it in as a replacement for the engine.
At 134kg per kW, a 3 kW Kilopower reactor comes in at 402kg, which is less than the 460kg we freed up removing the engine, fuel, and passengers.
So yes, order of magnitude estimates indicate that this is completely doable.