the real issue is indeed the fuel consumption. With high exhaust velocity's you can have low thrust but consume less fuel.
Considering that we use typical fusion Epstein Fusion engines with an exhaust velocity of 11,000km/s a 3500t Union might travel the distance from Solar Nadir to earth ~ 10AU
- by using its 214tons of fuel and an constant acceleration of 0.075m/s in 103 days hydrogen (150GW engine)
- by using 1g in 9 days but consume 2437tons of hydrogen (whooping ~19TW of engine power.... good luck in cooling that stuff)
So the Argo might violate existing law by correcting some issues.
Just found some calculations for the Leopard PWS (don't know why this...but its final weight was around 2500tons of those 900tons for fuel)
Considering that it should land on planets its necessary that the Leo can pull more than 1g (maybe they add some solid rocket boosters to the drop ship upon launching)
The fuel is water and for the normal cruise a electrolysis system will turn it into hydrogen
In cruise mode the Leopards fusion engine can accelerate for 1.4m/s - this would turn the 10 AU journey into 23days (accelerating all the time) - consuming 2/3 of its fuel (900tons in total)
this also ignores the fact that the used fuel is reduced mass so - it might be able to accelerate for 60% of the distance and decelerate using more thrust for 40%
With only 900tons of fuel - burn and coast is not saving much time (0.8days) - with bigger tanks you can safe maybe 3 days.
When you consider all this - specialization might be the name of the game.
Reinventing the whole BattleSpace. You have your interstellar jump ships, interplanetary tenders (like the argo) and finally the "real" dropships.
The tenders don't need to land on planets so they do not need multi g capable engines reducing mass and cooling and of course reentry armor - the drop ships only need enough fuel to make it from the ground into the orbit
Edited by Karl Streiger, 20 March 2018 - 12:02 AM.