291–300 of 351 posts
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Admittedly my knowledge on this matter derives from KSP, but I've found that rendezvous is much trickier outside of gravity wells. And there's still the problem of ISRU.
We have ISRU right here, right now.
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Any fuel you could generate on Mars would be overwhelmingly easier and cheaper to ship in from Earth; and you wouldn't need to land a million tons of freight on Mars first. A million tons of fuel delivered to LEO would take you quite a long way, and you could start immediately. If you want to go somewhere beyond Mars, stopping there and then starting again just sets you back. (Same goes for the moon, or lunar orbit.)…
A million tons of fuel doesn't cut the delta v requirements down. You'd have to ship the required fuel to Mars orbit (or wherever you plan on doing refuelling) still.
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Any fuel you could generate on Mars would be overwhelmingly easier and cheaper to ship in from Earth; and you wouldn't need to land a million tons of freight on Mars first. A million tons of fuel delivered to LEO would take you quite a long way, and you could start immediately. If you want to go somewhere beyond Mars, stopping there and then starting again just sets you back. (Same goes for the moon, or lunar orbit.)…
A million tons of fuel doesn't cut the delta v requirements down. You'd have to ship the required fuel to Mars orbit (or wherever you plan on doing refuelling) still.
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A million tons of fuel doesn't cut the delta v requirements down. You'd have to ship the required fuel to Mars orbit (or wherever you plan on doing refuelling) still.
If you need to refuel, send the fuel where it would be useful to get home with, i.e. where you are really going. Dumping it at Mars does no good. You would then have to stop at Mars to collect it.
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We have ISRU right here, right now.
You can't do ISRU in orbit. I don't know of any resources available on the Moon that would allow you to do ISRU there either. Ceres might work, but the inclined orbit may make that impractical as a stop.
"A stop" is not just useless, but is actively harmful in space transportation. You go, for free, until you get there, and then use up fuel stopping. Starting and stopping are exactly what costs. Stopping halfway makes the whole trip cost literally twice as much.
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You can't do ISRU in orbit. I don't know of any resources available on the Moon that would allow you to do ISRU there either. Ceres might work, but the inclined orbit may make that impractical as a stop.
We do ISRU all day, every day right here, in the millions of tons. "A stop" is not just useless, but is actively harmful in space transportation. You go, for free, until you get there, and then use up fuel stopping. Starting and stopping are exactly what costs. Stopping halfway makes the whole trip cost literally twice as much.
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If you need to refuel, send the fuel where it would be useful to get home with, i.e. where you are really going. Dumping it at Mars does no good. You would then have to stop at Mars to collect it.
That's assuming you have enough fuel to reach those destinations from Earth, let alone make it from Earth to there with enough payload for a return voyage.
If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra.
If you will need extra fuel to get home with, sending it to Mars is completely useless, because where you need it to be is not at Mars, but at the place where you will be at the time when you need it. That place is not Mars.
Is this really so difficult? Stop, breathe, and think.
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That's assuming you have enough fuel to reach those destinations from Earth, let alone make it from Earth to there with enough payload for a return voyage.
I see you are finding this very hard. Try to think it through: If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra . If you will need extra fuel to get home with, sending it to Mars is completely useless, because where you need it to be is not at Mars, but at the place where you will be at the time when you need it. That place is not…
This simply isn't true. From Mars to Jupiter is a little over 6 km/s of delta-v. From Earth to Jupiter is almost 9. The latter is just barely possible with SpaceX's Starship. The former allows for not only some breathing room, but more payload.
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What is there to break on a lifeless planet?
Whether there's life on this planet is not known, it's in the inhabitable zone so that possibility cannot be discarded.
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I'm probably an optimist on Mars travel. I think, with a fuck ton of starships, you could get people living on Mars. But there's some big asterisks on that. You'd more or less have to live in the starships, dependent on shipments from earth, with self sufficiency failing on pretty much every category. Over a very long period, most people would probably die a bit earlier from radiation and dust. Not much would be prod…
The suspicion I have about self sufficiency pessimism is that it's an apples to oranges comparison. Are there any modern analogies? As near as I can tell, it hasn't been required after the 16th century, due to access to relatively timely transportation. And if it hasn't been required, then how are we to look at existing practice and say we're bad at or incapable of it?