If we are to believe the pundits we are in the last few decades of
relatively cheap liquid fossil fuels, we are also being berated
interminably by the message that we are significantly effecting climate
with CO2 releases (personally I'm not 100 percent convinced that it is
entirely anthropogenic yet). At the same time it is I think unlikely
that people will be willing to accept significant drops in standard of
living as a result of these problems - so we need to find solutions.

Hydrogen sucks as a fuel for aircraft due to low energy density, we
could manufacture hydrocarbon fuels from biomass or even atmospheric
CO2 given sufficient energy, but I would like to propose a potentially
more efficient solution: the widespread use of commercial nuclear
aircraft.

The problems associated with nuclear powered aircraft are primarily
down to safety, so to offer a pathway into the widespread adoption and
use of nuclear power for aircraft I propose the following:

Nuclear Tow Planes.

We build Nuclear powered tow planes that are unmanned and completely
autonomous. These tow planes are sufficiently powerful to tow large
commercial jets and have reactors that are capable of operation for
several years at a time continuously aloft on a reactor load of fuel
(readily achievable).

These planes would initially only operate beyond the 200 mile limits
over international waters, far away from land where they could not
cause damage if they crashed. The planes will operate at say
3000-15000m in an environment where they are never exposed to the
dangers of foreign object ingestion, magnetic or gas lubricated
bearings can be used in the turbomachinery with relatively low Turbine
temperatures (say less than 950 deg C) and largish blade clearances to
ensure extremely long reliable engine life).

These planes would never land at airports thus avoiding the risks of
landing and takeoff and ensuring that no one will ever be exposed to
radiation.

Towing on a long rope ensures that passengers would never be exposed to
reactor radiation, and the reactor shielding could be minimal.

All maintenance and support for a large fleet could be done at an
isolated island facility (eg bikini atoll or the like), a
cradle/catapult launch system and recovery via redundant ballistic
recovery parachutes, or water landings could eliminate landing gear.
High lift devices could be eliminated leaving a very simple aircraft
with minimal systems that can go wrong.

Planes being towed could be converted from tubofans to turboprops for
takeoff and landing and with enough fuel to get to safety if the tow
failed for some reason, in flight the turboprops could be feathered.

A further refinement - and perhaps a major selling point, is the
possibility of making supersonic tow planes - towing aircraft around
the world at mach 2-3, anywhere on the planet cheaply in a single
flight of under 10 hours - this could open up a lot of new markets.

The tow planes can drop off one plane and pick up another straight
away, increasing their utilisation so that there is probably only the
need for one tow plane for every two or three international passenger
planes.

This idea can be sold to the public as an environmental boon - could
reduce CO2 emissions greatly, and could prove very economically
attractive with massively increased cargo capacity on long flights and
greatly reduced fuel bills. It probably only makes sense on
international flights of longer than 1 hour, but it could also make
international air cargo a lot cheaper opening up still further market
possibilities.

Bringing it back to space.. nuclear tow planes, possibly supersonic,
could also have application to HTHL assisted SSTO ala KellySpace,
Pioneer et al, with an onboard power excess they could possibly be
tweaked to make LOX and even condense water for LH2 manufacture for mid
air refueling. They would also be excellent for ferrying space planes
closer to the equator for low inclination launches.

Thoughts and comments?