IGNITION

Put your payload into an unpowered orbit. Spend less propellant. Keep Earth out of the flight path.

01 FILL02 FLY03 COAST

Build your rocket

01 / PRE-FLIGHT

LOX = liquid oxygen, carried on board. Fixed-Isp teaching presets; not exact engine replicas.

Empty rocket · kgPayload · kg

Propellant fraction by mass%

Propellant · kg

Launch mass40.00 kg

Ideal Δv 10.870 km/s

Not achieved speed: gravity and steering matter.

Target height · kmMission goal

Engine, prices & mission rules

Initial max T/WMin. perigee · km RP-1 · $/kgMethane · $/kg Hydrogen · $/kgLOX · $/kg

Prices are editable teaching assumptions, not market quotes. Cost includes fuel + oxygen only: no vehicle, tankage, liquefaction, launch service or operations costs.

Dry vehicle mass does not grow with tank size. Engine maximum thrust is sized to the chosen initial T/W, then stays fixed. This is an idealized point-mass rocket, not a buildable 1 kg launcher.

Teaching-price purchase$14.36

Consumed so far$0.00

Purchase / kg payload$14.36

PRE-FLIGHTT+ 00:00.0

Altitude0 m

Speed0 m/s

Perigee—

Propellant left—

Your orbit starts here.

Choose a propellant and mass fraction, then fill the glass rocket.

Global tracking

Inside the engineEMPTY

T = q vₑ · ṁ = −q

Exhaust, relative to rocket3.63 km/s

Rocket mass2.00 kg

Slow-motion schematic; not to scale.
Tank fill indicates mass, not volume.

Earth & trajectories share a scale. Rocket and exhaust are enlarged. Dashed path = engine-off prediction.

Flight control

02 / FLY

Simulation speed

Paused time never burns propellant.

Propellant ejection rate100%

Total fuel + oxygen · kg/s

Thrust 0 NT/W 0.00

Flow changes thrust, not exhaust speed.

Thrust direction

0° = local up · 90° = local horizon

Engine-off orbit checkNOT YET

Lowest point · perigeeInside Earth

Highest point · apogee0 km

Circular speed here7.910 km/s

Clear the safe altitude for the entire orbit, switch the engine off, and coast for 30 simulated seconds.

SPACE Pause / run X Cut engine
↑ ↓ Throttle ← → Direction R Rebuild

Show thrust & velocity vectors

Every burn tells a story

Propellant left · kgMass flow · kg/s

Launch to begin recording. Pause changes the controls, not the past. Export retains the recorded samples.

Local browser records. Matching challenge settings only; fuel and loading may differ. Guided runs are marked, never ranked.

RESULT	PROPELLANT	LOAD / USED	PURCHASE	$/kg PAYLOAD	PERIGEE × APOGEE	TIME	MODE

No matching flights yet. Your first verified orbit will appear here.

Class challenge: select Near-circular target for an apples-to-apples cost competition. Can you lower the loading fraction and still reach the same orbit?

Build your rocket

Orbit secured.

Flight control

Momentum, carried away.

High is not the same as in orbit.

What this model leaves out.