I’m still a bit concerned about radiation.
Still SpaceX builds launch “systems” and that looks like one nice spacecraft.
As time goes on being able to lift much heavy loads to orbit might mean radiation protection can be very thick lead/metals plus other materials. And then extra water protection areas. Still early days, who knows what new materials are we will create in the next decade to come.
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Hmmm…think we better find a solution fast because the earth has lost approximately 15% of it’s magnetic field over the past 200 years and is now estimated to be losing 5% per decade.
Human fast or geologically fast? I already said that even with zero magnetic field to block the solar wind, it would take many millennia to lose a significant portion of an atmosphere. I don’t see that as fast for human time scales.
I’m also interested in this because it’s not something I’ve heard about. Would you mind sharing your source on that? I do know that the magnetic field oscillates between the north to south pole, however, these shifts last over 10,000 years or longer for a single oscillation. I don’t see a significant threat from this issue compared to other threats such as asteroids, war between nations, nuclear annihilation, etc.
Yes, it will take a long time for the atmosphere to dissipate but that isn’t the main concern - it’s losing our shield against harmful radiation. At any rate, info is easy to find if you google it - NASA has also put out info on the subject.
A bloody shame public speakers are expected to always stay polite even in the face of stupid questions. Would be awesome to have a good cop bad cop setup where whenever a stupid question gets asked, the light around the “good cop” primary speaker gets dimmed and the light around the “bad cop”, an angry looking muscular person, gets turned up and he delivers a quick rebutal, voicing what many silently think.
E.g.
Can I come up there and give you a kiss?
Yes. On my ass!
WIll Mars be a dusty shitstorm?
Your life will be a dusty shitstorm if you keep wasting Q&A time!
Can I give you a gift?
Yes. SHUT UP.
Will you support a funny or die sketch?
If you die, that’d be funny.
Some dude even wanted to show Elon his electric bus… unless its the Camper from Spaceballs thats so far from the topic at the presentation…
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Yes I know it’s easy to find info about our magnetic field but I wanted your source of 15% of our B-field being gone with a prediction of 5% more per decade because I find that interesting.
Yes the our B-field does shield some radiation, but it’s mostly the radiation that just blows the atmosphere away. The atmosphere does a fantastic job of attenuating radiation hitting Earth. Cloud chambers are perfect examples of this in addition to being really cool.
That’s why radiation isn’t a huge deal on Mars once it gets an atmosphere, since that atmosphere will do a great job of stopping most radiation, even though there is already 1/1.5^2 % of Earths solar radiation at Mars. The biggest problem types are UV and x-ray both of which are easily stopped by an atmosphere.
As far as Earths Bfield goes, it’s something on the order of 115 25-60 microteslas or something tiny. It’s enough to stop weak particles from the solar wind but nothing more. A 10% change is still 100 23-54 uT and enough to ward off the weaker parts of the solar wind. Any radiation strong enough to give you cancer is going to shoot through the Bfield in the first place.
Edits: fixed numbers n stuff. Words too
Because it’s relavent I figured I’d continue talking about radiation during the travel. It’s only 3 months of additional unprotected radiation, but if you point the stern towards the Sun you always have the engines and both fuel tanks(the fuel) as protection to stop most radiation. It’s not as good as an atmosphere but it works for not much additional risk for only 3 months. Yes you will have a slightly higher chance of cancer by going to Mars. That’s a risk you will have to knowingly accept.
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I wonder will the spacex ship include a spin gravity device to give the crew a daily dose of 1g. They will need to be fit and strong when they get to the surface of Mars.
And what shielding they will opt to use, lead, water or surround themselves with food and stores to act as a shield for flare and other radiation.
I’m unsure of the risks from flares and other cosmic radiation on a journey to Mars orbit. I guess when and which course they take and when might also help mitigate radiation.
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I didn’t see them spin it in the video and the diameter is far too small to rotate it about the long axis without creating severe nasuea for the passengers.
As far as shielding goes they’ll use the fuel in the tanks and the engines. That’s all they’ve got. Lead is too much mass, although they do have an impressive 450tons to Mars which is frankly insane.
The nice thing about flares, if you can call them nice, is that you know what direction to point your shielding in and when it’s coming.
The magnetic field statistics does seem a little questionable, and a simple good search gave me the feel that maybe you might have referred something else was tapering off - the ozone layer, maybe? I would also imagine that Mars wouldn’t be that bad in terms of radiation. Europa, however, may be a little different.
Just some sidenotes from the IAC viewing:
42 raptor engines with 7 gimbals, 20% thrust. I found it very amusing that it ended up 42; I’m sure it has a mathematical reason, but it felt like a reference to The Hitchhiker’s Guide to the Galaxy. The deep throttle range seems that they can avoid the N1 problem, if the computer has to shut down one engine, it can lower the throttle on 3 engines on the opposite side, rather than shut an engine off completely. I’m not sure about this though.
If things go well, ~6 years being the first flight trip to Mars feels a bit rushed and optimistic, but I feel Elon has a way of getting unrealistic deadlines. Maybe he already operates on the Mars year, given it’s 1.8 years per Earth year. Heart of Gold was also an incredible name, consistent with his naming schemes.
By the time I got to the questions part I was let down. I was hoping to get answers to: Dealing with zero-G upon landing, radiation shielding, power generation (are those solar arrays actually enough?!) Though I guess that’s why these discussion threads here exist.
Also, can they steer by throttling the outside engines asymetrically?
At the very bottom of the booster, you can see 3 (or 4?) “slots” or “spikes” protruding outwards. Meanwhile, it looks like the bottom of the booster kind of “sinks” in to the launchpad when landing. So - does this mean no more landing legs on the first stage booster? With the shown design, the booster slides into the landing/launching pad, which also serves as a refueling interface. Interesting (and intelligent) design.
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The reason that Elon Musk is polite is that he is a believer in humanity. He treats other people with respect because he believes that people are worth it. He wouldn’t be trying to make mankind an interplanetary species if he didn’t.
Most people who are accomplished in life treat others with respect. Failure to do so generally means that people don’t want to work with you, and high accomplishments are something achieved through cooperation.
I speak of accomplished people because they are generally the most interesting public speakers.
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Yes. He mentioned rotating using differential thrust, that’s what that is.
Also yes the fins are to correct any few cms of being off center by physically centering the rocket, hopefully gently. That appears to be the plan anyways. Most cgi designs differ quite a bit by the time they reach production. Time will tell.
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I`m particularly interested in seeing some conceptual / design renderings exploring the interior crew space. If they’re not spinning the ship up then the space will need to be designed with Zero-G social interaction in mind… interesting design challenge I would think.
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There was one! Near the end of the presentation…I don’t know exactly what time but I’ll try and dig it up for you when I get some time. It wasn’t super detailed but it did a run through the habitable part of the craft.
Oh my yes, I did see that, however it looked quite barren. A lot of design yet to go into the space I imagine, especially if you’re designing for around 100 humans that may never see earth again… design to minimize homesickness and depression, while recreating the earthly environment that our species has evolved to live within… sounds like fun 
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So dark but true. This will be the ocean faring age all over again.
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I couldn’t possibly see what’s depressing about padded white walls 
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Well if you need the PDF of the presentation, it’s here: http://www.spacex.com/sites/spacex/files/mars_presentation.pdf
It’s all high res, so be prepared.
I haven’t found a transcript yet.
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Discusses the Elon Musk live stream.
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