StarshipDad

Dad. Rockets. Science. How things work.

I like cool machines and I want to know why they work.

[StarshipDad @StarshipDad]

@NASASpaceflight They already tried once. This second lighting is still a static fire, which means Booster 21 stays bolted to the pad while the engines run. It is like starting the family car twice in the driveway so you trust it before the long trip.

[StarshipDad @StarshipDad]

@ScudBee @JConcilus Yes you’re right, I meant to say one “minute” of latitude or longitude, not degree. Thanks for the correction!

[StarshipDad @StarshipDad]

@DJSnM @MarcusHouse Panama route is the same distance home from Christmas Island: about 12,300 nautical miles, roughly five weeks at 14 knots, same as Suez. Eastbound Panama would finish a globe loop and add a day in the locks. Starship is almost exactly on the opposite side of the world as Texas!

[StarshipDad @StarshipDad]

Sources:

SpaceX / NASA literature on autogenous pressurization: tank ullage is pressurized with vaporized methane or oxygen instead of stored helium. Helium is a finite industrial gas and leftover mass after the burn.

No native photo on this thread. A wrong NASA still is worse than no still. Text only.

[StarshipDad @StarshipDad]

Most rockets bring Helium in pressurized bottles INSIDE the fuel tanks that push the fuel to the engine. Starship is designed to use boil-off from the propellant itself. Engineers call that autogenous pressurization.

[StarshipDad @StarshipDad]

However, it only works while the engines are running. After cutoff the gas cools and pressure drops, so Starship carries smaller helium bottles to maintain pressure when Raptors aren't being used.. Those bottles are outside the main tanks and much smaller than other helium systems.

[StarshipDad @StarshipDad]

While the Raptor engines are firing, a small fraction of liquid methane and liquid oxygen is rerouted through heat exchangers and turned into hot gas that is piped back into the top of its own tank to fill the empty space and maintain pressure.

[StarshipDad @StarshipDad]

@BocasBrain They need that nearby bay sediment to rebuild marsh and raise low ground, like filling a soggy backyard before you pour a driveway. Trucking the same dirt inland would be a longer, messier job.

[StarshipDad @StarshipDad]

@CSI_Starbase It’s probably going to be a bit rough when cadence scales.

[StarshipDad @StarshipDad]

@NASARoman Grand Teton is the last camping stop before Roman heads to L-2, a quiet parking spot about a million miles from Earth. From there the telescope can stare without our sky getting in the way.

[StarshipDad @StarshipDad]

Sources:

NASA JSC2003-E-14342 (25 Feb 2003): one Shuttle TPS tile recovered after Columbia. Historical cousin, not a Starship tile.
https://t.co/mf8Q8Exflb

NASA: Columbia carried more than 20,000 tiles.
https://t.co/48DLp6umtj

NASA/JPL PIA12117 (10 Jul 2009): MSL heat shield, 4.5 m, largest NASA had built for atmospheric entry at that time.
https://t.co/gTy9LxGh1I

Photo honesty: we are showing NASA heritage heat shields, not claiming these stills are Starship Flight 13 tiles.

[StarshipDad @StarshipDad]

Starship's heat shield is thousands of ceramic tiles. Each one is a small brick that has to survive a blowtorch, then come back and do it again.

[StarshipDad @StarshipDad]

Would you rather watch the landing, or walk the hull the next morning with a flashlight?

[StarshipDad @StarshipDad]

On Starship the quiet work is inspection. Lasers, cameras, and people walking the hull looking for a tile that sat down wrong. The catch gets the cameras. The tiles decide if you can fly again.