Propulsion lab | Spacecraft Study

PropulsionSPACECRAFT / PROPULSION LAB

01 / Requirements & fundamentals1 of 31

LESSON 1

What must propulsion do?

Start with the maneuver, not the engine.

Insertion, orbit shaping, phasing, stationkeeping and disposal need a velocity change. Attitude control also needs torque, accurate small impulses and many starts. The same total Δv can lead to very different hardware.

Compare burn time with the time available near the maneuver location. A long electric thrust arc cannot replace an impulsive orbit insertion simply by matching Δv.

The fictional spacecraft preset assumes 2,000 kg final mass and a 1,000 m/s maneuver. These are adjustable study inputs, not results of orbit propagation.

THE RELATIONSHIP

mₚ = m(final) [exp(Δv/(g₀Isp)) − 1] tᵦ = mₚg₀Isp/F

m(final): final mass [kg] · Δv: velocity change [m/s] · F: thrust [N] · tᵦ: ideal firing time [s]

Explore the full vehicleOpen the tanks, feeds and engine together.

Chemical

Storable bipropellant

Preparing the engine…

Running · Illustrative tracers · motion slowedDrag / arrows: rotate · scroll / + −: zoom · Home: reset

THRUST400N

SPECIFIC IMPULSE310s

MASS FLOW131.58g/s

The cost of more ΔvFixed final mass

Chart data

Sampled plot values
Δv (m/s)	Ideal propellant (kg)
1,000 (selected)	778.991
0	0
350	244.037
700	517.851
1,050	825.075
1,400	1,169.786
1,750	1,556.559
2,100	1,990.525
2,450	2,477.442
2,800	3,023.773
3,000	3,365.391

MR = 1.389 · Propellant fraction = 28% · Ideal on-time 1.6 h

Educational modelConstant prescribed Isp and thrust. No gravity, steering or drag losses; engine shape and plume are illustrative.

Propulsion laboratory

Storable bipropellant