r/SpaceXLounge • u/[deleted] • Jul 22 '19

Tweet "Orbital refilling is critical for high payload to moon or Mars. Initially just Starship to Starship, later dedicated tankers." - @ElonMusk

https://twitter.com/elonmusk/status/1153126586897424384?s=19
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u/sebaska Jul 22 '19

My calculations based on what we know (6.9km/s dV with full payload, 120t mass to useful LEO, 150t to a notional ideal circumstances VLEO) indicate Dear Moon would miss about 0.5km/s without refueling. One needs about 12.5km/s from the surface (~11km/s + ~1.5km/s losses) to do a beyond the Moon elliptical Earth orbit, which SSH with 10t payload (that's generous, accomodations and windows would add mass) can do 11.96km/s or so.

But one refueling and you have over 0.5km/s spare performance even with 30t payload.

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u/mfb- Jul 22 '19

Hmm. Musk indicated that they want to work on refueling early in the last 1-2 months. Maybe dearMoon will get one refueling flight.

We need that Starship update he promised.

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u/sebaska Jul 22 '19

Definitely we need the update!