Category: Fun & Curios

Fun & Curios

Stuff That’s Hard to Do (28 Jul – 3 Aug)

DougM

BUSY WEEK: Falcon9 is back in operation
• SUN early am Falcon9, Starlink FL (300th booster re-flight)
• SUN morning Falcon9, Starlink CA
• TUE morning AtlasV, USSF FL
• THU night Falcon9, Starlink FL
• FRI mid-day Electron NZ local night-time

Starship Static Fire Awesomeness
Go full-screen

@52sec the three inner engines ignite

Fun rocket-engineering stuff (intro to exhaust shape):
• The three outer engines are optimized for on-orbit ops,
while the three inner engines are optimized for sea-level ops, i.e. landing.
• The larger expansion ratio produces low nozzle exit pressure to match atmospheric pressure in space,
so the plume gets squeezed into an hour-glass shape by sea-level atmospheric pressure in ground testing.
• The smaller expansion ratio produces a higher exit pressure that matches ground atmospheric pressure,
so it’s not squeezed and is more efficient for landing.
• Any mass not moving straight back reduces thrust and efficiency.
• Yes, this will be on the exam (slide rules only, please)