SpaceX Falcon 9 returns to flight

SpaceX is to resume liftoffs following an investigation into the massive explosion of a Falcon 9 rocket in September 2016. Accident investigators concluded that a helium canister burst during fuelling

Second stage: Explosion occurs while loading oxidizer – LOX (liquid oxygen) – and helium gas under high-pressure.
Helium is fed to fuel and oxidizer tanks to keep them at correct pressure levels as they empty during flight

Falcon 9
70 metres

Payload
fairing

Second stage

Inter- stage
adapter

Grid fins control flight when booster returns to earth

First stage

Landing legs

Nine Merlin 1D engines

Liquid oxygen tank: Supercold LOX at minus 207°C. LOX becomes solid at -218.79 °C

Fuel tank: RP-1 kerosene

Merlin 1D Vac engine: Generates 81,700kg of thrust in vacuum. Burn time of about 6.2 minutes

COPV: Liquid helium is pressurized to over 359kg/square cm, at temperature of -286°C. Accumulation of solid oxygen between aluminium pressure vessel and carbon-fibre triggers chemical reaction with carbon and ignition

Composite- Overwrapped Pressure Vessel: Three COPVs are installed within liquid oxygen tank

60cm diameter
1.5m long

Aluminium pressure vessel

Carbon-fibre composite

Sources: SpaceX, National Transportation Safety Board Picture: U.S. Launch Report