SpaceX CEO claims he can send you on a round-trip to Mars for $500K

http://www.extremetech.com/extreme/122923-spacex-ceo-claims-he-can-send-you-on-a-round-trip-to-mars-for-500k

by evo_9 • 14 years ago

141 86 14 years ago

warpspeed6• 14 years ago

While I'm sure it's a technical hurdle in itself, I didn't think that fuel or weight were the big problems with a manned mission to Mars. I'm curious as to what Mr. Musk's plan is for shielding passengers from intersteller radiation that one would experience outside of our magnetosphere.

The Apollo astronauts were exposed to approximately 1140 millirem over a 9 day mission, while the average here on earth is 350 millirem per year. Nuclear workers are limited to about 2000 millirem per year... so the approximately 52,000 millirem per year the astronauts would receive on a Mars mission is a problem.

mrsebastian• 14 years ago

Obligatory XKCD link: http://xkcd.com/radiation/

(100 rem = 1 sievert)

api• 14 years ago

Agreed. Maybe long distance manned space flight will finally kill radiophobia.

Groxx• 14 years ago

Following that math, the 9 day Apollo trip got 0.0114 sieverts. We'll round that to 11 mSv.

So in 9 days, they got 11x more than the EPA's yearly limit to the public, or 1/5th of the EPA's yearly limit to radiation workers.

The 520mSv warpspeed listed as a trip's radiation exposure comes out to 5x the lowest yearly radiation exposure 'clearly linked' to increased cancer risk.

So yeah. A problem, barring adequate shielding, if that number is correct.

albertzeyer• 14 years ago

Where do you have that 52,000 millirem (i.e. 520 mSv) number from?

Doesn't that completely depend on the thickness and material of the walls of the spacecraft? I.e., isn't it just a question of making the walls thick enough?

Daviator3• 14 years ago

That's what I was thinking. Not to mention, I would imagine that anti-radiation technology has surely grown in capability since the Apollo missions.

warpspeed6• 14 years ago

I occasionally get to work with the Astronomical Society and have gotten into a few conversations about manned Mars missions with people from NASA, JPL and various educational institutions. The numbers are from a study NASA conducted at Brookhaven National Laboratory.

The problem with shielding is the weight involved to achieve any level of protection.. wrapping the ship in enough lead to make a difference would be hard to get it off the ground. Also while this type of shielding may be effective against normal solar radiation, high energy galactic cosmic rays are far more dangerous and are almost unaffected by conventional shielding.

If you're interested, I recommend this paper. It goes a bit deeper into exactly why radiation is such a problem for any proposed Mars missions (warning, PDF):

http://spaceradiation.usra.edu/references/Ch4RadCarcinogen.p...

samstave2• 14 years ago

He said "round trip" - he did not claim what state you would be in upon return :)

architb• 14 years ago

This might sound like a stupid question, but here it goes. What if you lined the astronauts in a room with a control unit and really thick lead walls for most of the journey?

Could this theoretically stop radiation, and protect them? Lead blocks most radiation, specifically gamma.

ceejayoz• 14 years ago

Sure, but getting lead to orbit is hugely expensive.

A better solution is water. You need to carry it anyways.

marze• 14 years ago

Water works better. Heavy elements like lead splatter when hit by high energy particles and generate secondary radiation.

The idea is good, most mars plans include a shelter with a water or rocket fuel shield.

rsynnott• 14 years ago

> Nuclear workers are limited to about 2000 millirem per year... so the approximately 52,000 millirem per year the astronauts would receive on a Mars mission is a problem.

The limits for nuclear workers are extraordinarily conservative, so it may not be as much of a problem as you'd think. Given the safety track record of manned spaceflight, the radiation is probably the least of your worries.

mkn2• 14 years ago

We could be saved by the square-cube law, or, The Power of Being Big.

In essence, let's assume you've made your own fully-shielded space capsule for one, and that you need, for example, a pound of material for every square inch of its surface, and that you've made it into a sphere to economize on material. Wise choices, all of them. A 2m diameter capsule would come in at 19,500 lbs, or so, for that many square inches.

Congratulations. You've just found out why we don't shield small spacecraft. Now, however, let's get an estimate of what it would cost to shield 200 people, providing them each with a volume-equivalent of your capsule, or 4.2ish cubic meters per person. Really packing them in. This is a 11.6-meter diameter sphere, with roughly 3,300 pounds of shielding per person. At 2000 people, packed in like sardines, we're at 25.2 meters in diameter and 1550 lbs of shielding per person. A 54-meter sphere packs 20,000 sardines, and requires a mere 717 lbs of shielding per person.

A factor of 10-20 better. Obviously, we want to relax the space constraints a bit. However, the form factor of shielding in the larger craft is going to be much better suited to the reutilization of supplies as shielding. In the limiting case, of course, there is effectively no required shielding per occupant. Long before that, magnetic shielding schemes become a viable option, too.

A more practical limit would be to consider a transport module made up of re-entry craft seating 1-10 persons, with the ablative heat-shields and supplies facing outward. In this case, assume we can get down to 5 times your cross-sectional area in shielding, and guess that that's about 2.5 square meters. That's 4000/lbs per person. So, still a factor of 5 better than the solo case.

Additionally, this is a lot of arithmetic to ask of google and http://www.calculatorsoup.com/calculators/geometry-solids/sp..., so the numbers may be off. Also, the Dragon capsule checks in at 5.8 m^2 of heat shield per astronaut, which may be a practical limit. And I just made up the 1lb/in^2 shielding requirement.

bstpierre• 14 years ago

In other news, a one-way trip to Mars only costs $50k. If you don't make it, you can sue for a refund, but you have to sue in Martian courts, which won't be set up for a few more decades.

xspence2• 14 years ago

Is mars established as a credible planet/nation zone, or does it count as space (international)? Its an interesting perspective that the "zone" of mars could be a place of legal jurisdiction. But it seems that space is a free for all "zone", so maybe your lawsuit would be void?

warpspeed6• 14 years ago

According to the 1967 U.N. Outer Space Treaty, "outer space, including the Moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means. However, the State that launches a space object retains jurisdiction and control over that object. The State is also liable for damages caused by their space object and must avoid contaminating space and celestial bodies." (from Wikipedia)

So any crimes on Mars would probably fall under the jurisdiction of the country who launched the mission. Enforcement on the other hand might be tricky.

sgt101• 14 years ago

How is he going to do the landing? Human manned craft are going to be too big for bags, and the atmosphere is too thin for parachutes to work. Landing on thrusters is somewhat fuel heavy (so to speak).

blueprint• 14 years ago

Glider?

samstave2• 14 years ago

This is why I said we first need to conquer the moon. Send robotic building machines to the Moon, let them build habitable structures there first.

Then send these to Mars, have them remotely operated and autonomous and build a habitable setup there first without humans.

Then ship fuel pods to orbit mars which would allow you to go there with an empty lander - fill it up in orbit then land.

I think we need to take logical steps before we shove humans in a pringles can and launch them to mars.

warpspeed6• 14 years ago

Like this: http://www.youtube.com/watch?v=BudlaGh1A0o

edit- Parachutes are probably more practical. They work if you make them big enough.

ballooney• 14 years ago

Your mass scales with the cube of linear dimension. Parachute drag scales as a square of linear dimension.

What this means is that the chute gets bigger much more quickly than the payload as you increase lander mass, to the point that you quickly get outlandishly large and impractical chutes for manned landers. Hence the research into alternatives.

Delphiki2• 14 years ago

I haven't gotten a chance to read the article yet, but is he planning on landing at all? I would imagine it would be much easier to just go there and back, without landing...? Much more fuel efficient and technically still "round trip."

ef4• 14 years ago

Robert Zubrin published a detailed plan for generating rocket fuel on Mars several years ago. His book "The Case for Mars" is a good read.

Such a technology really is a game changer for the economics of the mission. And you can send your robotic fuel factory and make sure it's working before you commit to launching people.

inchcombec• 14 years ago

I've actually got that book in my collection and you're right, it is a good read.

The idea of producing rocket fuel on Mars is not only a good one, but quite likely the only way such a mission would even be viable. The idea of hauling all that extra rocket fuel for the return trip to Mars and back simply doesn't work.

benl• 14 years ago

The full-length interview this story is based on is on this page:

http://www.bbc.co.uk/news/health-17439490

Just skip the stories and listen to the audio, it's much more informative.

vannevar2• 14 years ago

He's relying on generating fuel on Mars, which considering that we've barely scraped the Martian surface with robots is highly speculative. Mars travel is still beyond business planning and into the realm of futures studies. I love SpaceX, but they haven't yet demonstrated they can reliably deliver payloads to Earth orbit on a regular basis. They're a long, long way from Mars.

mkramlich3• 14 years ago

I've heard some experts in the field say that the hardest parts about space travel are the launching and the landing. The middle parts, like the long boring flight and keeping the crew alive and not crazy, are massively easier and less risky in comparison, engineering-wise. They've shown they can put something into orbit. Landing on Mars with humans will be tricky, but the technology seems to exist to allow it, and that general kind of thing has been done before. Parachutes and thrusters, etc.

vannevar2• 14 years ago

I don't doubt that SpaceX can get to Mars eventually, maybe even within 10 years. I really hope they do, I'm rooting for them. But I seriously doubt they will be ferrying space tourists out there for $500K apiece in any timeframe that would fit in a business plan, even a very long-term one. We're decades away from that kind of capability.

adaml_623• 14 years ago

I'd rather go to the moon. The view is better.

pjscott4• 14 years ago

If you're interested in spectacular views, it's hard to compete with a mountain three times the height of Mount Everest:

http://en.wikipedia.org/wiki/Olympus_Mons

Mars also has an atmosphere suitable for flying around in with helium or hydrogen balloons. You could mount a camera on a bunch of balloons and get some amazing pictures.

If you don't mind my saying so, "The view is better" doesn't sound like your real reason for preferring the moon.

pyrotechnick• 14 years ago

He means the view of Earth from the moon vs from Mars.

joeyh• 14 years ago

The problem with Olympus Mons, when it comes to views, is that when you're on it, it's too big, and too gradual a slope to see off it. Also, when standing at the base of it, the summit is off over the horizon. Give me Valles Marineris any day.

michaelkscott• 14 years ago

I'd choose Pluto for some stunning views: http://en.wikipedia.org/wiki/File:ESO-L._Cal%C3%A7ada_-_Plut...

duxup• 14 years ago

Can't get that much time off of work. What can you do for me over a couple weeks?

damoncali3• 14 years ago

What is it about this guy that allows him to make such claims and not be laughed out of the room? It's an amazing an useful talent that, oddly, I first witnessed as a young engineer on NASA's Hubble Space Telescope project.

The head of the servicing missions was a boisterous, outrageous, personality (some told me it was what held him from higher positions within NASA). He was the kind of guy who brought in a sales guy for a rapid prototyping machine (a 3D printer starting at $1 million), walked in half way through the presentation, and then promptly kicked the salesman out for not having a $200k offering.

He was also the kind of guy who demanded composite structures yielding 10X the mechanical properties of the current state of the art materials. But with no research projects, development, or anything even close to it. Just "get it done".

Of course, we didn't get it done (because it was impossible), but what we did get done was a major leap forward. We used materials without, gasp, flight heritage. We used the absolute state of the art in some cases. We got it done, it's just that it wasn't what was asked for, at least not directly.

This smells of the same thing. But don't underestimate the shear force of personality it takes to make such outrageous claims, and still have people follow you to something remarkable, yet more realistic.

spoiledtechie• 14 years ago

This reminds me of Atlas Shrugged, when the entire community is against the stars for the book building the Rail Road. They don't believe it possible.

I would actually say, don't underestimate perseverance. Might sound like he is an optimist, but I think you have to be with anything to do with spaceflight. At least at this day an age. I would also consider him an expert in the subject, and what are you?

Daviator3• 14 years ago

I think it's pretty cool that not only is he the obvious owner of the entire enterprise, but he is the chief technology officer because he is a self taught aeronautical engineer for lack of a better descriptor in this case. One of his degrees is in physics, sure, but one of his real ambitions in this instance is reading everything and talking to every expert he could in this field.

The point of the matter is that this kid did his homework and deserves everything he will earn in this endeavor.

pjscott4• 14 years ago

I would say that he's got a fair amount of credibility now because he made his own space program. When you've made good on enough implausible claims, the criteria for "implausible" change.

simonsarris• 14 years ago

If you want to build a ship, don't drum up the men to gather wood, divide the work and give orders. Instead, teach them to yearn for the vast and endless sea.

-Antoine de Saint-Exupéry

I think personalities like Musk are behind the above quotation. A dreamer with demands, and the demands are concrete in the respect that they may be technically possible while still being dreams - be they Mars at 500K or yielding 10x the mechanical properties. I think people are drawn to such personalities because it seems to be the most encouraging way you can possibly frame a dream.

bergie• 14 years ago

Dream no small dreams, for they have no power to move the hearts of men - Goethe

lacker• 14 years ago

If you want to build a ship, don't drum up the men to gather wood, divide the work and give orders. Instead, teach them to yearn for the vast and endless sea.

That quote sounds pretty awesome. However, in the real world that's not how most ships are built. There's a lot more "giving orders" than "teaching to yearn". It's not like the shipbuilding industry is famed for the dreamy yearning of its laborers.

InclinedPlane• 14 years ago

He created a company from scratch that builds rocketships. A company that has launched a pressurized capsule into orbit. If his company was a country there would have been a human in that capsule and it would have made a lot more news than it did, as it was it still stands as an impressive achievement. And achievements give you a lot of credibility.

damoncali3• 14 years ago

Impressive, but not sufficient to explain the power of his personality - which is enormous. For example, Orbital, a public company that builds rocketships, was also started from scratch by one man with a vision (and without the resources of Musk, I might add). And yet you've likely never heard of them.

There are lots of experienced, credible people who cannot do what Musk does with his outrageous dreams (and they are outrageous - to Mars and back for the cost of a upper middle class home in the US - think about that). To dismiss his impact as the consequence of success is to miss the true source, I suspect.

mkn2• 14 years ago

There a couple of things that allow him to make these claims without being "laughed out of the room," as you say, but they don't have to do with his personality in the sense in which I take your meaning.

First, there is the rocket equation. That little gem tells us the amount of fuel it takes to achieve a given change in velocity for a given energy density of fuel. Then there are some results from orbital mechanics and aerodynamics that tell us what that change in velocity is. For the curious, escape velocity is just sqrt(2) times the circular speed at any given altitude.

I've laid this out before, but here it goes again. To put a pound of anything into orbit has a fuel cost of a little over $20. "Incredible!," you say, "It costs $10k/lb on the Space Shuttle! How can that be?!" Like so. Typical mass fractions are on the order of 2%. That is, 2% of the stuff on the pad, fuel, structure, payload, everything, actually ends up in orbit. About 12% of that mass is structure, things like tanks and engines and the like. That leaves 86% of the thing as fuel. 86:2 is 43:1. 43 lbs of fuel for every pound of payload. Assuming that propellant is roughly as dense as water and roughly the price of milk, both easily verified, that's under 6 gallons of propellant for every pound of payload, which will run you $21 at $3.50/gallon.

Multiply sqrt(2) by $21/lb and you have something like $30/lb. If you and your capsule weigh 2,000 lbs, That's $60,000 for a one way ticket. A little over 8 times that price may be a reasonable number. So, what makes up the difference in cost for current launch systems, or even for antiquated and clunky systems like the Shuttle? Low safety margins and their concomitant need for enormous administrative costs for each part, disposable launch systems where that administration cost burns up in the atmosphere or splashes down in the Pacific, and enormous system complexity driven by a lowest-flight-weight-results-in-the-cheapest-vehicle mentality.

We can begin to address, based on SpaceX's design philosophy and planned vehicle, how they may be able to make these claims without deserving to be "laughed out of the room."

First, SpaceX has reduced engineering and integration costs by reusing common components and simplifying designs at every step. they were (and I think, still are) using a pintle injector which is much less susceptible to catastrophic combustion oscillations than the more typical injector-face solution, at a cost of some performance. The tanks for all of their stages are the same diameter, allowing them to engineer and build one capital-intensive jig rather than two or three, and they get more experience with that hardware since all their work is done on it. They're using a pneumatic stage sep mechanism rather than a pyrotechnic one to eliminate material-handling, static, and other safery concerns related to pyrotechnics. Rather than relying on one or a few very large engines to power the first stage, they've chosen to use 9 smaller engines on the first stage and isolate each one in its own cato-proof container, again allowing them to gain more experience with a single system, prove its reliability, and leverage that experience and track record to perform a larger job.

Second, they have plans for full reusability of the launch system based on incremental changes to their existing systems. Yes, there is a fuel and performance penalty for going this route, but the savvy armchair aerospace critic will note that those penalties are expressed in tens of dollars per pound, whereas 100% disposal is measured in thousands to tens of thousands of dollars per pound. That is to say, even if reusability results in a 10-fold increase in fuel cost but allows vehicle cost to be amortized to negligibility, we're still approaching Musk's $500k/flight number. As to his actual plan, the fuel cost to land a booster segment is tiny compared to the cost of launching a vehicle. The first stage will simply reenter without having to retro-burn, and the second stage will need to retro-burn just enough to enter the atmosphere to achieve the rest of the braking. After that, the delta-v required is on the order of 100m/s, hardkly the 10km/s needed for orbit. You seem to know what you're doing, so I leave the derivation of that penalty, using the rocket equation, to you.

tl;dr: You're absolutely wrong in the most irrelevant way, and had you addressed SpaceX's achievements and plans in anything like a rigorous way, you could easily have answered your own question.

EDIT: The fuel cost for escape will not be sqrt(2) times the cost for circular speed. The real factor will be something more like 2 or 3, not 1.414... Still, we're in the range of $60/lb, not $6,000/lb.

damoncali3• 14 years ago

Amortizing away the development and other fixed cost is cheating a little, no? I mean, we don't even know how to keep someone alive for the trip yet.

Reasonable people can disagree, but I wouldn't bet on Musk being alive to see the first successful round trip to Mars. But I also wouldn't bet against something truly amazing coming out of his activities.

jackpirate• 14 years ago

which will run you $21 at $3.50/gallon

So I was going to call bullshit on your price for rocket fuel given that regular gasoline is more expensive than this, but I looked up the price [http://www.desc.dla.mil/DCM/DCMPage.asp?PageID=722] and it turns out that's pretty close to the current price for JP-5. The most expensive fuel the DOD uses, JTS, is only $6/gallon.

linuxhansl• 14 years ago

Maybe fly to the moon first before you tackle mars?

pjscott4• 14 years ago

If anybody feels like going to the moon, I'm sure SpaceX would love to handle the launches.

kamaal2• 14 years ago

To me going to moon looks like a more interesting prospect than going to mars.

Androsynth• 14 years ago

This is great and I fully applaud him for this. But when I go, I won't be coming back http://en.wikipedia.org/wiki/Mars_to_Stay

rwhitman• 14 years ago

So you can drop a half million dollars and spend 2 years of your life in a tiny compartment millions of miles from home to visit a dead, cold, rusty rock without a breathable atmosphere?

Does that sound unappealing to anyone else?

Zaak4• 14 years ago

I expect there are many people who would find that very unappealing. I also expect that there are people who would put down the money right now if you would let them.

repsilat• 14 years ago

There are people who would put down the money for a one-way trip.

mmahoney• 14 years ago

It sounds awesome personally

mkramlich3• 14 years ago

I don't find the idea of jumping out of a plane with only a parachute (that will probably open OK. maybe) to be appealing, yet thousands of people do it every year, willingly, and repeatedly. And that's downright mundane compared to the obvious exoticness and thrill those kinds of folks would get from setting foot on the planet Mars.

pygorex• 14 years ago

> Of course, there are many skeptical experts out there that have pointed out the fact that SpaceX has only attempted a rocket launch seven times. Of those seven, three were total failures.

Ouch. I hope that $500,000 is refundable in case of death or accident.

> Any human that makes the trip will be stuck inside the vehicle for the 214 days it would take to actually travel to the Red Planet.

I once made a road trip from Seattle to Tennessee in 3 days. In the middle of a frigid winter. During blizzard conditions. Of course we took breaks to get out of the car, stretch our legs, have a piss and get some fresh air. At the end of the trip I was ready to hang myself. The boredom and rigor of endless driving became unbearable. The prospect of taking a similar trip, over a much longer timespan, in much more hostile conditions and paying for the privilege is not appealing, at all.

pjscott4• 14 years ago

To be more specific about their flight record: the first three test flights were failures, back when they were still working out the kinks on the Falcon 1. The flights since then -- including both Falcon 9 launches -- have been successful.

nl• 14 years ago

The boredom and rigor of endless driving became unbearable.

Well the good thing is that you won't have to do the driving part..

kamaal2• 14 years ago

There is huge difference between traveling to places on earth and space and the motivation to do so. On earth you might be traveling for whatever boring reason.

Imagine if some one told you Shangri La actually exists and you have to bear some pain for an year to get there. What would you do? Will you take some pain to get there and live at Shangri La for some days?

I definitely would. And I'm sure many would.

SpaceX CEO claims he can send you on a round-trip to Mars for $500K

Related Stories