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Blue Origin Thread (merged)


Aethon

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Lifting bodies are nothing new. I think what Firemetal is referring too is the huge window on the front and the magical solar arrays that fold out of nowhere.

It definitely has a sense of "form defines function" instead of the opposite, like a Hollywood spaceship designed to look cool and then making up technobabble to justify the styling.

1 hour ago, Mitchz95 said:

If an absolute imperative comes along, I doubt we'd have the time or the resources. The colony wouldn't be self-sustaining for decades if not centuries, anyway, so it's better to get started right now while we have the will and the way.

And what sort of imperative would that be ? What would you actually save and for whom ? There is no single event that would make Earth less hospitable than Mars, or that would create population bottleneck smaller than the population that could be sustained on Mars. In fact, a Mars colony would be much easier to wipe out than 1% of Earth's population. 

The "backup of humanity" analogy simply doesn't work. It would be like backing up your PC to an old 3.5" floppy drive, and storing it on top of a loud speaker cabinet in the sunlight. And that 3.5" floppy would cost a decent portion of your revenue too.

Edited by Nibb31
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Earth could be rendered uninhabitable by any number of scenarios. In that situation humanity is saved by an offworld colony.

Also, in a sufficiently large disaster, even with a 1-5% survival rate civilization on Earth would collapse. With all the easily extracted resources already extracted, there's no reason to assume advanced civilization could emerge again second time. An advanced society based on Mars could bootstrap us back into the space age.

There are plenty of reasons why getting off this planet permanently is good for humanity's long term prospects.

Edited by RCgothic
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We've gotten into this argument before, but I can see the "backup of humanity" argument as being rational. That said, I don't see it in any sort of near-future timeframe, more like many hundreds of years or more. Of course the effort to push ourselves farther out from LEO at all does pay a dividend, even without actually "backing up humanity"---we gain the capability to much more effectively mitigate planet-killing threats. The ability to rapidly put several hundred tins in LEO, for example...need not be ITS, it could be a smaller craft with a ton of dv compared to what we could loft now to match with, then divert an asteroid.

Clearly  we could be more efficient by focusing on that threat for our spacecraft vs settling Mars, but honestly it is not "cool" enough until we actually need it (then a rush program might not be fast enough), so other stuff is more likely to get funded.

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31 minutes ago, Nibb31 said:

And what sort of imperative would that be ? What would you actually save and for whom ? There is no single event that would make Earth less hospitable than Mars, or that would create population bottleneck smaller than the population that could be sustained on Mars. In fact, a Mars colony would be much easier to wipe out than 1% of Earth's population. 

A big enough asteroid impact is the standard answer. People might survive the actual impact, but the food chain would be mostly gone. Kind of too late to be building big spaceships.

And any kind of colony anywhere else is easy to wipe out. The early European settlements in America died like flies. We only remember the ones that survived, and don't remember that they did it by the skin of their teeth. For example, Plymouth only survived because the Indians took pity on the idiots and taught them how and what to plant. We have several colonies that vanished w/o a trace where we don't even know what happened.

But we kept trying.

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And that's just an argument for multiple colonies, not zero.

Mars would actually be much less vulnerable to global catastrophe too. With power mainly from nuclear and enclosed habitats, there's not much an impact on the other side of the planet could do compared to a similar atmosphere-disturbing event on Earth.

Edited by RCgothic
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Actually, a big thread of SF (especially Heinlein) is that the people that leave Earth on the rockets are the smart ones, and the colonies become powerful groups of self-selected geniuses. Earth degenerates to a useless pile of idiots that squanders their remaining resources. Watching the presidential debates and hearing the questions to Musk's presentation, I can't disagree.

And on a personal note, I'm not looking any further than getting an unmanned Red Dragon on Mars, then we'll see about the more fanciful stuff. I think there's a 50% chance SpaceX will do that in less than 10 years, and I think there's an actual 10%-20% chance they can land something manned on Mars.

NASA has said "Mars is 15 years off" ever since 1965 and I believe them about as far as I can throw a Saturn V. I give them a zero percent chance of doing anything useful further out than LEO. I don't think NASA could land someone on the Moon again if their life depended on it. I don't think the manned asteroid mission is going to happen, and I'll be surprised if SLS launches more than once.

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1 hour ago, RCgothic said:

Earth could be rendered uninhabitable by any number of scenarios. In that situation humanity is saved by an offworld colony.

No, not really any. There really aren't many scenarios that wouldn't leave a few million survivors

An asteroid big enough to completely obliterate the Earth is unlikely. The Earth has pretty much cleared its orbit and a rogue Moon-sized object on an intersecting orbit would have been detected by now. Any likely collision event with global repercussions would still give us plenty of time to react. The dinosaurs weren't wiped out overnight, it actually took decades or centuries to kill them off. A large number could make it through an event like that with current technology.

So then it comes down to the expense/risk ratio for your backup plan, which is a classic insurance-type calculation. What proportion of your revenue are you willing to spend for a specific insurance policy that covers your house from something highly unlikely, like an alien invasion ? 

Quote

Also, in a sufficiently large disaster, even with a 1-5% survival rate civilization on Earth would collapse. With all the easily extracted resources already extracted, there's no reason to assume advanced civilization could emerge again second time. An advanced society based on Mars could bootstrap us back into the space age.

A handful of people on Mars isn't much more capable than a collapsed civlization on Earth. If Earth is destroyed, it won't be coming back.

Backing up humanity is like backing up your family by sending your youngest child to live in Antarctica, just in case your country is wiped out by a zombie invasion. If your family dies, all you have achieved is that your child is alive in Antarctica (for now). There is no backup, and you're actually exposing your child to a much higher risk by sending her away than by keeping her with you.

 

Edited by Nibb31
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8 minutes ago, Nibb31 said:

Backing up humanity is like backing up your family by sending your youngest child to live in Antarctica. If your family dies, all you have achieved is that your child is alive in Antarctica (for now). There is no backup, and you're actually exposing your child to a much higher risk by sending her away than by keeping her with you.

Except dumber than that, because at least your youngest child is strongly enough related to you to be worth the effort.

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15 minutes ago, Nibb31 said:

A handful of people on Mars isn't much more capable than a collapsed civlization on Earth. If Earth is destroyed, it won't be coming back.


This.  The only way a Martian colony functions as a "backup of humanity" is if it's a healthy and entirely self sufficient colony - something that has never really been tried, even on Earth, even back before the Industrial revolution.  The challenges of setting up such a second civilization (because once it's self sufficient, it's not really a colony anymore) are immense and costly.  Everyone babbles on about the rockets, but really rockets only rate a footnote in the appendix compared to all the other issues the space fanboys don't talk about because they aren't sexy rockets.

And that's real issue here - the whole "colonize Mars" and "backup of humanity" are just figleaves to give an excuse for a discussion of rockets.

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8 hours ago, Rakaydos said:

The advantage is you can refill the tanks on your transfer ship (without needing to empty equally large tanks on your lander) if your transfer ship is your lander and you fill up on the ground.

You lose the same amount of payload lofting the extra fuel, whether its a tanker/lander refueling a mothership or a single ship. And a mothership needs enough fuel to orbit, whereas the singleship can do direct entry.

With a purely orbital transfer vehicle you wouldn't need to refuel though. Stripping the belly heat shield, landing gear and all but one of the engines would boost the dV massively. It also wouldn't need the dV to get back off Mars which is one of the main sinks for it.

It could just be refuelled in Earth orbit each time like the ITS is planned to be once launched.

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After watching the video, I think project is quite unrealistic even by KSP standarts.

Especially all-in-one SSTO and Mars to Earth transfer spaceship... With casinos and hookers aboard :) 

And transfer for 30-60 days - non Hohmanns tranfers -  what amount of delta-v this thing must have?

Edited by evileye.x
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Mars SSTO is only about 4km/s dV  and Earth transfer is a bit above 2km/s dV (assuming aerocapture).

Considering that they have unloaded most of the payload on mars,   6km/s dV is not that high.

Edited by Nefrums
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42 minutes ago, Nefrums said:

Mars SSTO is only about 4km/s dV  and Earth transfer is a bit above 2km/s dV (assuming aerocapture).

Considering that they have unloaded most of the payload on mars,   6km/s dV is not that high.

You mean nobody is going back home from Mars vacation? Consider life support, heat shielding for successful Earth aerocapture... 6km/s is not that low. And faster-than-Hohmann transfer will require more dV anyway....

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15 minutes ago, evileye.x said:

You mean nobody is going back home from Mars vacation? Consider life support, heat shielding for successful Earth aerocapture... 6km/s is not that low. And faster-than-Hohmann transfer will require more dV anyway....

Putting the numbers given at the presentation into the rocket equations (isp 382, dry mass 150t, propelant mass 1950t) we get that the payload capacity is ~350t at 6km/s dV.

Comparing this to the given payload to mars: 450t. gives that you would need to unload about 100t cargo in order to get back.

Faster transfers would require more dV (less payload) that is true.

 

Edit: They also stated that the would make only 600t of fuel on mars, coincidentally this gives just above 6km/s dV for 0 payload. Guess this is based on that no one wants to come back.

Edited by Nefrums
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Trying to imagine, what should happen with the Earth to get the following at once:

  • Temperature got -100..150°C
  • Atmosphere disappeared at all. Pressure < 0.01 atm.
  • Ocean disappeared except two polar caps.
  • Soil disappeared at all, only sand and stones left.
  • Flora/fauna disappeared at all, totally sterilized planet.
  • Magnitosphere disappeared at all. (Core had frozen?)
     

Martian backup colony: better build on the Earth.

5 hours ago, GeneCash said:

but the food chain would be mostly gone.

On Mars it had not even started.

5 hours ago, GeneCash said:

Plymouth only survived because the Indians took pity on the idiots and taught them how and what to plant.

There's air in Plymouth.
There're no Indians on Mars.

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5 hours ago, GeneCash said:

For example, Plymouth only survived because the Indians took pity on the idiots and taught them how and what to plant. 

Aye, and how do you think the Indians got there in the first place?

This is exactly what I mean by 'settlement' being better than 'colonisation' in this context, the word colonisation brings up all these connotations that don't apply, and causes analogies with no relevance to the situation. The initial settlement of the Americas by the people we now call the natives is a better analogy, though there are still obvious issues.

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4 hours ago, evileye.x said:

After watching the video, I think project is quite unrealistic even by KSP standarts.

Especially all-in-one SSTO and Mars to Earth transfer spaceship... With casinos and hookers aboard :) 

And transfer for 30-60 days - non Hohmanns tranfers -  what amount of delta-v this thing must have?

I'm sure the numbers add up. Elon wouldn't be that bold, to present something on  a congress about astronautics that can be dispelled by one dude in the audience with a basic knowledge of orbital mechanics and a HP 15C at hand.

There are a few things that raise my eyebrows though:

  • Economic feasibility is based on reuse of the same booster, tanker and transfer vessel. If I understood the presentation correctly, they're building three ships; the tanker (maybe two, to speed up the process?), the SSTO (kinda) booster and the mars vessel. With at least two fuel launches per mars trip that's three SSTO launches, giving us 30-50 SSTO launches and landings over the lifetime of the project. Not a single one of those landings (not to mention launches) can go wrong and we've seen the track record of the Falcon 9 so far, and they won't have the luxury of a dozen test launches (with the occasional vehicle loss) to test things out. 30 times landing something the size of a Saturn V, with a 100% success ratio. Not 95% success, not 99% success. 100% success. I love Elon and Space X and their bold approach to things, but with this... good luck!
  • Bill Nye points this out time and time again (and he's the first to point out the value of feet-on-the-ground expeditions): set up a self-sustaining colony on Antarctica. If you can do that you're 3/4 on the way to building a Mars colony. And with self-sustaining he means "not dependent on air-dropped supplies."  If that sounds hard, keep in mind that the Arctic environment does a pretty good job of mimicking Mars (except for a high-pressure, oxygen rich atmosphere). The whole "and this is how we think a Mars colony will look like" is missing and that's a bit suspicious.
  • 100 people per trip, $200,000 ticket per passenger. Let's be bold and assume 50 trips in total. That's 5,000 passengers. Total ticket revenue: one billion dollars. Now, there are days I don't carry that in my wallet, but that seems awfully low to bankroll the entire project. Is there additional revenue? Are passengers who want to return to earth extorted and expected to pay $1,000,000 for a return ticket? Is there some sugar daddy who bankrolls the rest? I'm pulling numbers here out of where the sun don't shine but I'd think that it would cost at least 20 billion to pull something like this off.
    The insurance cost alone... And the project has to factor in the loss of at least one launcher (while landing, destroying the launch pad, causing delays, etc) I'd say. Financially it doesn't add up.
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 With a 363 s vacuum Isp, I get an "ideal delta-v", which is the delta-v without gravity and air drag losses, of over 11,000 m/s:

363*9.81ln(1 + 6700/275) = 11,500 m/s.

Using the ideal delta-v number, the required delta-v to orbit is in the range of 30,000 ft/s, about 9,100 m/s; so this value is well above that. That translates into significant payload to orbit if you only require a delta-V of 9,100 m/s to get to orbit.

Modern Engineering for Design of Liquid-Propellant Rocket Engines, p.12

14ipea8.png

 

 

  Bob Clark

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I wish people would stop talking about SSTO. There is no SSTO in any part of Musk's plans, except the direct launch from Mars surface.

The ITS booster is nowhere near SSTO. It separates at around 2500m/s. The whole point of refueling the ITS in LEO is because it burns all of its propellant to reach LEO.

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There will be a third type of ship launched from the top of that booster. one with a cargo hold like the space shuttle, but bigger.

With 360t cargo to LEO

That one is going to make all the profits needed to finance the rest.

Edited by Nefrums
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2 minutes ago, Nibb31 said:

I wish people would stop talking about SSTO. There is no SSTO in any part of Musk's plans, except the direct launch from Mars surface.

The ITS booster is nowhere near SSTO. It separates at around 2500m/s. The whole point of refueling the ITS in LEO is because it burns all of its propellant to reach LEO.

You're right! That addresses all my concerns! It's totally feasible. Totally!!

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1 hour ago, Kerbart said:

You're right! That addresses all my concerns! It's totally feasible. Totally!!

Oh but you're actually completely right with your concerns. There are even more big issues with the plan when start scratching the surface:

  • Designing an ECLSS that supports 100 people for 6 months.
  • Landing on an unprepared surface with Raptor engines only a few feet above the surface.
  • The ridiculous pricing coupled with the lack of funding.
  • Ability for LC-39A to handle such a big rocket.
  • Manufacture interplanetary spaceships that cost less than an average airliner.
  • The lack of a legal framework regarding a settlement effort on another planet.
  • Handwaving away all the vital technology that doesn't exist yet (ECLSS, ISRU, rovers, habs, food growth, ice mining, etc...)
  • Handwaving away potential biological unknowns (radiation, partial gravity, toxicity, etc...) that might make settlement impossible.
  • The requirement for other people to fund the actual colony so that it aligns with Musk's timeline 
  • The unrealistic design of the spaceship (huge window bay, magical folding solar arrays, no radiators, no comms, no docking ports, small cargo doors, impractical unloading, small footprint)

Some of those things have solutions, but probably not in a timeline anywhere near the one that was presented, and potentially not in a way that fits Musk's vision.

Edited by Nibb31
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I think any "backup" arguments require not some "settlement," but a 100% self-sufficient society that has appropriate genetic diversity by definition. If it's not that way, it's not "backing up humanity." So don't argue against the concept based upon it being like sending your daughter to Antartica, assume that it's sending a few million people to live in Antartica who need never communicate with anyone else, ever, and will do just fine.

I'm fine with arguing that it's not cost effective (it isn't), or that it would not possibly happen for many hundreds of years or more (it likely wouldn't, even if we tried starting now). The concept is not absurd, however. We've already done a "backup of humanity" version 1.0, maybe even version 2.0---we left Africa, then sailed across oceans. A planetary scale disaster in East Africa a few million years ago might have killed all of us (our direct, ancestors pre-Homo sapiens). Once we spread to the near East and Europe, we were a little safer as a species, and once we became global, we are even more safe.

Honestly, I think any permanent settlement in space outside of the Earth-Moon system would need to become entirely self-reliant (which is why I think these "colonization" efforts are unlikely in the near future). So it merely becomes a requirement for a sufficient number of humans, and for them to obviously not require supply runs from Earth every 2 years (or ever).

Regarding possible dangers at the scale we are talking about, we'd likely not have much warning, because as was said, we've cleared our orbit, and we know the recurring threats. It would be something new perturbed into a highly eccentric orbit, or perhaps an extra-solar body. What we'd need to mitigate that risk would be better space telescopes and the capability to react quickly to such threats (appropriate craft with very high dv to play with). Both are certainly facilitated by a more "space faring" society.

Edited by tater
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