Spaceships in Lowell Was Right! are built on a choice of "hull" - really a spar and attached module arrangement - and a choice of two drives for each "hull" available. One drive is a Burn-Drift-Brake type, and the other uses a constant low-fractional-G thrust. This means transit times between planets are measured in months rather than days or hours.
Burn-Drift-Brake (B-D-B) drive uses more energy, and requires more of
its mass to be fuel than the Slow Boost drive, which means the Slow
Boost ships can carry more payload than B-D-B ships. On the other hand,
B-D-B ships are much cheaper, and the very slow but constant
acceleration of the Slow Boost means that B-D-B ships are faster over
On this, you can hang components - Crew Cabins, Passenger Cabins, Rotating (for false gravity) Passenger Cabins, Air Plants, Workout Rooms, Cargo, and more. What you won't find is weapons. Weapons available in Lowell Was Right! are pretty useless in space.
only Artificial Gravity is through thrust or rotation. Thrust is either
tiny or brief, and rotationally induced gravity is very expensive.
Luckily, since radiation is space is all electromagnetic, and since
calcium loss in bone was not a known effect in 1880, in Lowell Was
Right!, weightlessness is for most people perfectly healthy, once you
get used to it - though you may want to build up those muscles if you
plan on going back to a planet...