How is the Space Engineers atmospheric lift worked out?

Space Engineers

Atmospheric Lift

Leaving a planet in Space Engineers comes down to thrust against weight, and you would much rather discover a shortfall on paper than halfway up.

Atmospheric Lift

Total Mass (kg)

Grid Size

Thruster

Planet

Large Atmospheric

Small Atmospheric

How the numbers are worked out

Two things set the thrust you need: the gravity of the planet and the mass of the ship once it is loaded. On top of that, every thruster type has a very different output depending on whether there is air around it. Pick the planet and your real cargo weight, and the calculator gives the count of each thruster type required.

The formula

force needed = ship mass × planet gravity
thrusters = ceil(force ÷ (thrust per unit × atmospheric efficiency))

Common mistakes

Ion thrusters do almost nothing in atmosphere and shine in vacuum — which is why a ship that handles perfectly in space cannot get off the ground. Size atmospheric thrusters for take-off and ion thrusters for everything afterwards.

A worked example

A 100-tonne large-grid ship on an Earth-like planet has to push against 981 kN of weight: 100,000 kg × 9.81. Two small atmospheric thrusters, 648 kN each, just clear it at full efficiency. On the Moon, at 2.45 m/s², the same ship weighs a quarter as much, which is why a ship that struggles off Earth can be lively elsewhere.

Leave real margin

The count is the minimum to hover, not to climb. Cargo, ore and ice add mass during a trip, and atmospheric thrusters lose efficiency as the air thins with altitude, so a ship that barely lifts off can stall halfway up. Plan for well over the minimum, and for heavy haulers add a second thruster type that keeps working as the atmosphere fades.

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