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Comment by avmich | Hacker News Reader

> about a dozen trips per day per Starship

Gagarin flew for around 108 minutes, so orbital velocity allows longest trip between two points on Earth in about 54 minutes. Shorter trips could be less, but liftoff-landing take roughly a fixed amount of time.

Twelve trips per day is 2 hours per trip. Taking 40 minutes of flight, there are 1 hour 20 minutes to get onboard, to get off board, to handle luggage (if needed?), to refuel and check systems. Wonder how does it look from airlines operation prospective.

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That stands pretty much parallel with aviation turnarounds - it’s purely logistics. If they don’t need to do any maintenance other than standardised checklists between flights, which is their ambition, there’s no fundamental reason they couldn’t do this.

A (very) cursory search turned up this[1], which suggests they can turn around what appears to be a relatively short haul aircraft in ~50 mins arrival to departure.

My uneducated guess would be that refueling of a starship alone is likely to take a long time if you're pumping in 1,200 tons of fuel.

1. https://your.heathrow.com/happens-aircraft-turn-around-briti...

Do all orbital flights take off in the same direction due to the rotation of the Earth?

"Most" would be more accurate.

Flights that want to orbit over the poles take off aiming perpendicular to the rotation instead. A few satellites have been launched backwards intentionally.

I think sun synchronous orbits are retrograde

P2P sub orbital hops are either direction, 30-40 minutes, maybe 25 for shorter trips like London to New York.

Agreed that P2P sub orbital hops are any direction.

Low sun synchronous orbits are approximately the same as polar oribts, more perpendicular than retrograde. I'm not sure if we use high sun synchronous orbits for anything?

Sun sync is approx 98.7 degrees at 800km - so slightly retrograde (prograde being 0-90)

Majority of LEO sats are sun sync

All satellites that want to efficiently get into somewhat equatorial orbit do.

However, satellites heading to polar orbits of course launch north or south, and famously Israel launches things into retrograde orbits, due west, because of lack of suitable launching locations that head east.

In the case of suborbital hops, it doesn't matter, because your target isn't orbital speed, and what you lose in free speed you gain back in your target coming towards you as you hop.

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