Stuff That’s Hard to Do (28 Jul – 3 Aug)
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
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)
Furlongs per Fortnight vs Microns per Sidereal Month
Besides,
a real American can use both systems
This is Why We Have Software-Based Voting
Remember, Democrats, you don’t really have to vote
