Friday, March 3, 2017

Bezos > Musk

I'm going to lay out a prediction here that will be hard to judge for decades. I think Jeff Bezos will prove to be more important than Elon Musk in the to-be-written history of mankind moving out into the cosmos. I'm a big fan of Musk and SpaceX, but I think Bezos has a better focus. Musk is focused on Mars because he wants to settle humanity off Earth as quickly as possible. However it's too soon for Mars. We need regular cheap access to orbit first, then to develop resources and infrastructure in Cis-Lunar space, then the asteroids, and so on. We are a long, long way from being able to settle Mars in a sustainable manner.

By way of comparison, the Vikings discovered and settled the New World centuries before Columbus, but they couldn't do it sustainably. They didn't have sufficient sea faring technology to make for regular trade between the New World and Europe, or for mass immigration. It took Europe several more centuries to build the technology needed for regular trade with and settlement of the New World. I don't think it will take centuries for us to get where we need to be to settle the rest of the Solar system, but we still need to do a lot of work to get there - and Bezos (and Robert Bigelow, and Made In Space, and Planetary Resources, etc.) are the ones doing that work.

If Elon ends up being more important than Bezos, it will because he realizes this and pivots SpaceX's business model to closer to Bezos' current vision.
"Our ultimate vision is millions of people living and working in space. We have a long way to go." - Jeff Bezos

Blue Moon

Days after Elon Musk announced a tourist trip around the Moon, a paper has been leaked describing Jeff Bezos' pitch to the new Trump Administration for "Blue" Moon missions by 2020.

There's a couple things here which are extraordinary-
  • If Blue Origin plans to be flying to the Moon by 2020, their New Glenn rocket must be closer to flying than we've previously heard of.
  • The paper mentions a "Blue Moon" lunar lander, which we've never heard of before. The paper says it's based on New Shepard, which makes sense if you want to cut down development time.
  • The paper indicates the ability to put 10,000 lbs of mass on the Moon. That's cargo, and doesn't include the mass of the lander itself. That's a lot! If this is based on a single launch architecture (and I assume it must, as we are unlikely to develop on-orbit refueling in three years), this confirms that New Glenn is closer to SLS and Falcon Heavy than the Falcon 9 in terms of performance.
That last bullet is really important. Here's the money-quote from Bezos:
“Blue Moon is all about cost-effective delivery of mass to the surface of the Moon,” Bezos wrote. “Any credible first lunar settlement will require that capability.”
Dollars for kilograms. That's what has been missing from NASA for the last half-century. The Apollo rockets were amazing, and the Shuttle was neat, but what has been holding back space development for the last half century is that the cost to reach orbit stubbornly stayed around $10,000/lb. At those prices, nothing significant is ever going to happen. And SLS was never going to change that.

But finally Musk and Bezos are changing that. And of the two of them, I think Bezos is the more-focused one. So what sort of costs are we talking about?

We don't have pricing for New Glenn, but the Falcon Heavy (before reusability) has a base cost of $90 million per flight (actual flights cost a little more than this, due to integration costs and so forth, but this base is still useful), and Musk has indicated that partial reusability (5 flights per first stage) should reduce costs by 20% and full reusability (at least 20 flights per stage, all stages fly back) would reduce costs 80%. According to those estimates we get the following:

                    LEO/lb  GEO/lb   Mars/lb
Expendable  $90m    $  750  $1,840   $ 3,000
Partial Re  $60m    $  600  $1,470   $ 2,400
Fully Reus  $18m    $  150  $  367   $   600

We don't have exact numbers for the Moon, but the Moon is easier to get to (in terms of delta-v) than Mars. We also don't have cost numbers for the New Glenn yet, but we know that New Glenn will start out with "Partial Reusability" and that Bezos eventually wants to get to full reusability. So look at the second and third lines in the table, and compare those numbers with the $10,000/lb that the Space Shuttle cost to put stuff just in LEO.

NASA has been able to maintain the International Space Station for the last 20 years with $10,000/lb launch costs. If Bezos can put cargo on the Moon for a fraction of that price, there's no reason a manned Moon base is out of the question.

Tuesday, February 28, 2017

To the Moon!

SpaceX is going around the Moon.

The projected date is late 2018, but that's ambitious (as all SpaceX dates are). I believe Elon when he says that Dragon 2 will fly next year, but going from first test cruise to Moon trip in a single year is ... ambitious (there's that word again).

But regardless of whether it's in 2018 or 2019, this is very cool. This is going to be the kind of spectacle that will make a lot of people sit up and take notice. Whoever these paying customers are, they'll go down in history as the first private citizens to fly beyond Earth orbit.

And that's a good thing. NASA has been futzing around for years with their SLS and Orion programs, wasting billions, and they don't have a single rocket to show for it yet. The first planned test launch to LEO is for late 2018 (and then it plans to fly again in 2021 (woo!!)), the same time that SpaceX plans to be flying tourists to the Moon. And from there things don't improve for SLS, as their projected flight tempo is one flight every 2-3 years at a cost of $1-2 billion per flight (depending on how you accrue program development costs). Those sort of costs are great for the cost-plus contractors that fund Congressional campaigns, but if the rest of Congress (who doesn't get kick-back money from SLS contractors) starts paying attention they might start to ask why NASA is paying 10x as much for a rocket that flies 1/20th as often as Falcon Heavy.

What you'll surely here next year though, in defense of SLS, is that Falcon Heavy doesn't have enough power to launch a Moon lander or Mars lander. "We need SLS if we want to actually land anywhere, and not just do fly-bys!" they'll say. And that's true to an extent. The Falcon Heavy doesn't have enough power to land a crewed Dragon 2 on the Moon as long as you have to launch all your fuel at the same time.

The mass of the fuel needed to land on the Moon and return is the limiting factor. As long as we keep sending up the fuel and the crew vehicle on the same rocket, we will need to keep building ever larger and more expensive rockets.

But this is not actually necessary. The current Dragon spacecraft can berth (aka, get close and then be grabbed by the Canadarm) with the International Space Station, and Dragon 2 will be able to dock (aka, mate with a docking port using its own propulsion; no Canadarm necessary) with the International Space Station. A craft that can do this can also dock with an external fuel tank in orbit.

So watch for that, because while circling the Moon will be the big bang of 2018 (or 2019), refueling in orbit will be the prelude to the next one.

Thursday, February 23, 2017

Give me a home where the asteroids roam

Astronomers discover seven Earth-like planets around a nearby star

Or so the headlines tell you. But what does "Earth-like" mean? To give you a sense of what I mean, if we were studying our own solar system from afar, Mercury, Venus, Earth, and Mars would all qualify. And yet, three of the four aren't especially habitable.

Human beings are very clever about adapting to environments on Earth. Populations of humans are found all over, from the equator to above the Arctic circle. But all of those environments have constants which do not change, like gravity and the mix of gasses in the atmosphere. We already know that variations in the air we breathe can be deadly, and variations in the amount of sunlight over a 24-hour period effects long term human health. What if the day was something other than 24 hours? What if the gravity was 90% of Earth?

I'm pessimistic that humans can adapt to environmental factors which are especially different from Earth. Even if there are a dozen planets in every solar system, the odds of any planet being a close-enough match to earth (atmospherically, gravimetrically, and otherwise) to be a good fit for unmodified humans are slim.

However that does not mean I am pessimistic about human settlement of the solar system or the galaxy. It just means we should stop focusing on planets. Planets can be pretty hostile, they exist at the bottom of an gravity well that's very hard to safely enter and exit, and as a percentage of possible habitable real estate they're not even especially large.

Also, if you've read anything about the efforts that would be required to terraform a planet such as Venus, you know that's not a reasonable amount of work for the payoff. Not when there's a better alternative.

Much better than a planet is a small moon or large asteroid belt that can be mined for resources. Ordinary steel from a nickel-iron asteroid could be transformed into an O'Neil Cylinder habitat with an inner surface area of 10,000 square miles. Assuming (within reason I think) that we improve our ability to mass-produce carbon materials such as nanotubes and grapheme, the carbon from an asteroid could be turned into a Bishop Ring with an internal surface area of 1.2 million square miles (about the size of Argentina or India).

And those surface areas are just the top deck where people would probably choose to live, on account of the Mediterranean weather that's maintained year-round. There's no reason you couldn't have multi-level habitats with sub-levels for agriculture, infrastructure, and industry. Fields of rice won't care they only have 50' of headroom. So the upper deck numbers are pure residential land area.

The real benefit of ring habitats is you can produce 1g of gravity for the inhabitants without going down into a gravity well. This is important because if you think about a future where most humans live in space (not on Earth), you want to be closer to the trade networks connecting the many nations. From an energy point-of-view, living at the bottom of a gravity well is sort of like living on a remote mountaintop, whereas living in orbit is like being at a major sea port close to the world's shipping lanes. From earth the only way to get to the shipping lanes is taking a rocket; but from a Bishop Ring you can take an elevator.

So it's nice and all that we found seven planets. That's fine. Science is cool. But from the point of view of whether these planets will ever serve as a home to future humanity, the answer is "Probably not ever". Instead a colonization ship will set up shop in orbit around these worlds and produce 1,000 Earths worth of Mediterranean real estate from their moons, while on the (probably very hostile to human life) surfaces below we will only send robots for mining or scientific inquiry.

Wednesday, October 26, 2016


Otto, the self-driving semi-trailer company acquired by Uber, has made its first commercial delivery. Meanwhile Uber is launching its software product UberFreight, which seeks to match cargo with trucks and drivers (just as regular Uber matches drivers and fares).

I don't know if these particular efforts will be successful. Uber has the resources to deliver here, but they might be beaten by other companies. Nevertheless, these are signals of the world that is slowly emerging and I'm still trying to wrap my head around it all.

Consider also-
That's just a taste, the trend is pretty clear. Every form of vehicle is being converted to self-driving variants. Not just Google's car, but planes, ships, and cars, and new categories (such as that little grocery delivery bot, as well as small flying drones) are emerging too. And trains will too, I'm sure. Further, the regulatory and liability hurdles that are faced by UAVs (by which I mean everything from an unmanned autonomous 5lb drone to an unmanned autonomous ultra-large container vessel) with human passengers are much lessened for freight vehicles, so they will probably emerge into commercial applicability first. Commercial operators also have fewer emotional connections with their operations, so they won't hold onto human-operated vehicles out of nostalgia. As soon the cost-benefit numbers are there the transition will be swift.

It's hard to overstate how huge this is. Freight shipping defines the global economy. Anything that lowers the costs of shipping, reduces time, and/or increases volume will have knock-on effects throughout the economy as markets expand in scope and local specialization deepens. The Roman Empire was built on its roads and its control of the Mediterranean. The British Empire was built on its control of the oceans, and consequent trade via tall ship (and later steam ship) between Europe, the New World, and Asia. Container shipping is an ongoing revolution as container ships get ever larger. These changes were all inflection points in the integration of the global economy, and UAVs are going to be another one.

Tuesday, October 25, 2016

The 10,000,000 Year Ship

I've seen a lot of discussions and potential designs around how to build starships capable of reaching other star systems. Everything from huge generation ships with hundreds of crew to wafer-thin "ships on a chip" sailing on starlight. But I was thinking today about how you could send a ship to another galaxy.

Without getting all mathy, the distances between galaxies is freaking huge. The Andromeda Galaxy is 2.5 million light years away. At even 0.25c that's a 10,000,000 year trip. How could you possibly design a ship to last that long? What would it look like?

First, a couple assumptions. I'm not assuming any new physics or "magic" technologies. That's actually probably unrealistic over these time frames, but I don't care to speculate in that way. So we are talking about ships that have, at best, anti-matter acceleration and they cannot reach the relativistic speeds where time-dilation slows down the observed journey to within human lifetimes. If the EM Drive works, and/or the Alcubierre warp drive works, then we can revisit. For now I'm assuming a top speed of about 0.25c.

With that said ...

My first thought is that we can rule out sending physical human bodies. I'm not sure there's a level of cryostasis that would keep a human brain from succumbing to entropy over that timespan. So we are talking about a seedship that will grow humans once it gets there. Human DNA would also be subject to entropy, but if you have enough copies (easy to do with DNA), you should be able to peace back together a working genome at the other end.

In fact, entropy is your main enemy over these distances (more so than crashing into things - intergalactic space is pretty empty). That probably rules out any sort of active nuclear isotope battery. Anything that has a usable level of radiative energy would probably have radiated away by the time you get there. You could probably bring some Thorium-232 with you as long as it was kept shielded from neutrons. Thus you could have the parts for a thorium nuclear reactor on board, but what would you use to put that into operation? You'd need the equivalent of a battery and spark plugs to turn the engine over.

I'd say the key technology you'd need are transistors that don't age. No growing new crystals, no deterioration in the electrical properties, over 10,000,000 years. Super, super stable chemistry. Once you have that you make solar panels, batteries, and on-board compute and sensor systems.

From a design perspective you want to expose as little of the front edge of the ship as possible to oncoming H atoms you might crash into on your long trip. But you also want a lot of surface area for solar panels. I'd say the best shape is a hollow cylinder with a narrow leading edge with a stable shielding material, maybe water ice, to act as a bumper. The outside surface of the cylinder is solar panels all the way around. There could also be a central solid cylinder where all your key hardware is, connected to the outer cylinder with thin spokes.

The ship would be designed such that the light from a distant galaxy cannot power anything, but merely being within a galaxy provides enough solar power to turn on some basic senor systems. Once you pass beyond our galaxy's light the ship will lose power and go into a fully suspended operation mode, just coasting through the intergalactic space on momentum. Once you enter into a new galaxy the solar panels will start collecting solar energy again and turn on basic systems.

Now here's the real question, what kind of maneuvering ability would you have once you got there? I'm thinking two kinds.

First, we rule out anti-matter. It's possibly you use anti-matter to accelerate up to cruising speed, but I doubt you could bottle anti-matter for 10,000,000 years. More likely the bottle would fail at some point and the ship would destroy itself in deep space. No, you need a chemically and "nuclearly" inert system.

Second, you have to realize that we cannot aim for a particular star from the launch point in the Milky Way, so the computer will need to be able to wake up at the destination galaxy and pick a star, and hopefully have time to maneuver before it crashes into something. (It's probably best if you send multiple ships on slightly different trajectories)

The two best possibilities are probably storing a solar sail for the long journey and an inert gas ejected through ion thrusters. Mostly a solar sail, because it doesn't require bringing any reaction mass with you over the 2.5Mly trip. You then maneuver for a close encounter with a star and use gravity assists to slow down. Possibly more than one, making for a very long deceleration phase - but if you survived a 10My journey, a couple thousand more years here or there isn't a big deal.

One of my assumptions is that no civilization would try this until they've already mastered how to send Von Neumann probes throughout their own galaxy, so once you manage to get into a stable orbit around a destination star in your new galaxy, you'll just initiate that program out of the box. That's the easy part. It's designing a system that can coast for 10,000,000 and then wake itself up and maneuver at the destination galaxy that's hard.

Wednesday, September 28, 2016

SpaceX: The Mars Plan

I've had a thousand thoughts bouncing around in my head since Elon Musk's Mars keynote yesterday. It's a lot to take in, and I was trying to organize my thoughts. However Jonathan Goff at Selenian Boondocks and Eric Berger at Ars Techica have offered some good takes already. You should read them.

Selenian Bookdocks: Jon's First Take
Ars Technica: Musk's Mars Moment

Like Eric and Jonathan I'm excited by the possibilities and I'm a lot more enthusiastic about this architecture than anything NASA is working on, but there's also quite a few things that worry me.

Part 1: Non-Mars Stuff

Skip this if you only want to talk about Mars.

Falcon 9: Even More Thrust?
Just sort of off-hand, Elon mentioned that the bulk of SpaceX engineering right now is focused on a "final" version of the Falcon 9 due next year. I previously had no idea there would be any more versions of the Falcon 9. I thought the Full Thrust model was going to be the last one. What could they possibly be adding? I really doubt they'll move the Falcon 9 to the Raptor engine (and methane fuel), as that would require a redesign from the ground up. That would be a whole new rocket. So what are they adding to Falcon 9? I have no idea.

Part 2: Concerns

As Jon summarized, SpaceX is pursuing both world-beating performance per launch and reusability at the same time. Just to give you an idea of how much performance we are talking about, here are the thrust/weight ratios of some well known rocket engines:

Engine    Vehicle   T/w ratio
SSME      Shuttle      73
RD-180    Atlas V      78
F-1       Saturn V     94
NK-33     Soyuz       136
Merlin 1D Falcon      180

As you can see, the SpaceX Merlin 1D is already the best rocket engine in the world. Now Elon wants to triple that? At the same time, adding the material reinforcement necessary to withstand 1,000 launches (as they are hoping their BFR will reach) worth of wear and tear only makes your thrust/weight worse. Is tripling what's already the best-in-class number even believable? It's a lot to swallow.

Interplanetary Transport Ship (ITS)
I think the ITS can be thought of (and probably is thought of within SpaceX) as a really, really, really, really big Dragon 3. The ITS tries to be a lot of things. It's a second-stage rocket boosting out of Earth gravity with near-SSTO performance even without its booster. It's an in-space habitat for 100 people (20x the ISS crew complement) for 80 days. It's also a lifting-body decelerator (like the Space Shuttle) that ends up landing on its butt on Mars (or any other solid body in the solar system).

Any one of these things would be amazing. All three of them in the same vehicle reminds me of the F-35 Joint Strike Fighter. A cruise ship that's space-rated and flies?

The only reason to do all these things with one vehicle is because you lack a real infrastructure of more specialized vehicles. As Jonathan also mentioned, a lot of the cost of SpaceX's architecture is that the ITS can only be used once every couple years when the planets align. It's dead weight (economically) the rest of the time. If you broke up the architecture into things that could be used during the other 22 months of the bi-annual cycle, you'd spread your costs out over a lot more missions.

For example, imagine instead of the 100 Mars colonists launching up in the same vehicle they fly to Mars in, you built instead the equivalent of a space-rated 737 sitting on top of a Falcon 9. That could take the colonists to a colonial transport ship which stays in orbit all the time. You board up when it's time to go to Mars, but the rest of the time the same 737-like vehicle could fly passengers to space stations in Cislunar space or maybe even Lunar destinations.

Similarly, Robert Bigelow is building large inflatable habitats for space already. They can't land on and take off from Mars like the ITS, but they're cheaper and more effective as habitats because of that. The BFR proposed by SpaceX can launch 300 tons to orbit per reusable launch, which is big enough to put (I'm estimating here) maybe a 50-60 person Bigelow module in orbit. Attach some solar panels and a couple vacuum-rated Raptor engines to that and you've got your colonial transport. And during the months when Mars isn't in the right place for a colonial mission, you could rent out the space in the Bigelow module to commercial or scientific missions.

If you built something like an ITS for transporting crew and cargo from Mars orbit to the Mars surface, but it stayed at Mars all the time, you could use it all the time for point-to-point travel on Mars, moving cargo or fuel between Mars' surface and orbit, or even accessing Phobos and Deimos. It would also be designed just for that, and wouldn't have to have all the hardware necessary to keep 100 humans alive for months at a time.

To reason by analogy, there's a reason people drive to the airport in cars, fly to Tampa in a plane, and then sail around the Caribbean in a cruise ship - rather than have a cruise ship pick them up at their house in Cleveland and fly the thing door-to-door to the B&B in Nassau.

Solar Power
Elon's keynote and the animations only showed one power source for the system - solar panel arrays. I imagine you could also hide some methane fuel cells on board and run them off the methane in the fuel tanks, but they would be a backup power source.

Solar power is not a bad way to go for small probes and satellites. But the size of those solar arrays, rated for 200kw (2x the ISS) indicate that the IST will need a lot of power. Moreover, Elon tried selling the ITS as a "go anywhere in the solar system" ship, but solar power doesn't work much beyond the asteroid belt.

Simply put, ships of this size, and missions beyond the asteroid belt, will need nuclear. Elon mentioned the need for "public cooperation" to get nuclear power on Mars, and what he really means is that the Department of Defense will have to get involved to build nuclear power plants. They have decades of experience building them for carriers and submarines after all.

Fuel Depots
SpaceX is moving to an architecture where the colonial ship is launched with dry fuel tanks, and then it is topped off. That's good, because it massively improves performance. The BFR (assuming it flies as designed) will launch 300 tons per launch, but the ITS says it will take 450 tons to Mars. The difference is the fuel that will be loaded into it once it's already in orbit.

However you'll note the immediate problem which is that the ITS cannot be loaded with fuel until it's already in orbit around Earth - with all its colonists already on board. How long will it take to launch multiple tanker flights to it?

A much better architecture would be to have a large, passively-cooled fuel depot in orbit. The tankers could spend months or years (whenever there is a free launch window) loading up the depot, or the depot could even accept fuel from in-space sources such as the Moon or asteroids if that ever comes online. Then when the ITS launches it would top off its tanks from the depot, rather than wait in orbit for multiple tanker rendezvouses.

Alternatively, if the ITS launched without colonists, it could be the fuel depot itself for a couple months, and then the colonists come up in a 737-equivalent when the Mars window opened.

Biggest Concern: Too Much, Too Soon
My overall concern, which is reflected in all my other concerns, is that it's too much, too soon, and the over-complication of the ITS is really driven by the fact that there isn't an infrastructure in place to support this yet.

For instance, Elon say he's trying to be the rail road to Mars. That makes sense, to an extent, but he's trying to build a railroad to a place with no humans to build the railroad, no oil or coal to fuel the engines, or anything else. The ITS is less like a railroad to California and more like an all-in-one expedition to Antarctica.

I think the companies that are trying to gradually build up in-space resources by first, e.g., building a business to refuel the satellites already in orbit, then start getting fuel from near-earth asteroids, then go to the Moon, etc. are going to be more successful in the long term.

Elon's project is the ultimate example of a Moon Shot. And most Moon Shots fail.

Funding & Partnerships
This is where I think Elon said the least but implied the most. SpaceX cannot afford all the up-front costs associated with this, and they probably cannot sell a significant number of "tickets to Mars for one" decades in advance. Their launch business and eventual satellite business will produce a lot of cash flow, and Elon would probably be willing to sell off his Tesla stake at some point to pay for this, but that really only covers the R&D and early prototype work. Getting from there to "hundreds of ships in orbit all leaving for Mars at once" isn't within SpaceX's capital budget under any scenario.

And to be absolutely clear, the $200,000 (or less) ticket price only works (if it ever works) once the system is fully at scale. It may genuinely only cost $150,000 to land the 10,000th person to on Mars, just like it genuinely costs only $50 to fly from L.A. to Las Vegas, but that's only because all the planes and airports already exist. Landing the first person on Mars will cost $10-20 billion.

What I think is happening is that Elon is trying to play NASA off against some other national governments. Maybe not China, but possibly Europe or maybe some rich Middle Eastern country. The question that every national space agency is going to ask themselves is "Are we going to let [that other country] land the first man on Mars?"

America was the first and is still the only country to land men on the Moon. That's a huge part of our national pride and self-conception. Do you think Congress would be happy if the first men on Mars were a couple of Saudi Princes who paid $1 billion each for the privilege? Or even a joint EU-Japan mission?

The challenge that Elon needs to overcome for NASA's support though are the contractors who currently suck down $$billions each year building NASA's Space Launch System and Orion craft. There's no room in NASA's budget for both SLS and the BFR. It's one or the other, and the Senators and House Reps in the pocket of Boeing and Lockheed will fight like hell to keep the SLS gravy train going.

Elon has a powerful card to play though. Humanity only lands on Mars for the first time once, and the people who do so will probably be remembered for as long as written records from this era persist into the future. Just as we all know that Queen Isabella sponsored Christopher Columbus, who will history remember as the sponsor for taking humanity to Mars? Is it going to be Saudi Arabia? Will history say that Bill Gates had to pay for it because Congress was too captured by Boeing? You better believe that SpaceX lobbyists will employ this argument at some point.

Part 3: Open Questions

In Situ Resource Utilization
The transport system outlined by SpaceX had four major hardware parts - the booster, the colonial ship, the tanker, and the ISRU system for making fuel on Mars. But we saw exactly zero information about the ISRU plant. Has SpaceX even started designing what it would look like? How much fuel can it produce? At what rate? Can it be shipped to anywhere in the solar system and assembled on site? Does it need people to operate or is it 100% robotic? We have no idea.

The entire proposal (both Mars and destinations beyond) rests on the ability to produce fuel at the other end of each trip. There's no trip back, no reusability, without ISRU.

Martian Gravity
We know that zero-g is terrible for you. We have no idea whether Martian gravity is strong enough for long-term human health. We have no idea whether Martian gravity is strong enough to allow a woman to carry an infant to term and bear a healthy baby, or what effects the gravity will have on a growing child. Frankly the whole discussion of making humanity multi-planetary is entirely premature until we answer this question.

Free-space & Asteroids
Elon always talks about planets. He never talks about all the resources in space itself. His focus for humanity is always planetary, never in-space habitats as detailed by Gerald O'Neil. The resources of the Solar System in space are many times greater than the resources of any planet. Solar power is more abundant, the asteroids can be mined in their entirety (as opposed to a thin surface layer like on a planet; you can't mine a planet's mantle or core), and rotating 1g habitats could be mass-produced to create internal surface areas sufficient to accommodate any level of colonization. But Elon never talks about this. Why? Would the BFR be available to people who are willing to try?

Part 4: The Good Stuff

Despite my concerns, I'm still very excited and wish SpaceX the best of luck. Here's a short summary of why.

The Vision
NASA's vision of "Journey to Mars" is basically the same idea as Apollo. Spend a lot of money, send a few missions of a few people to Mars, and then stop. Flags & footprints are nice, and they're certainly a nice feather in the cap of the United States, but they don't change the picture for humanity. Even the Norsemen who tried to settle North America in the 10th century had a bigger vision than NASA.

Will Elon's particular mission architecture work? I have no idea. I have many concerns. But I'm glad as hell he's trying to do it. The American people can look at what SpaceX is trying to do and turn to NASA and say "What the hell, man? Why is SpaceX trying to build a whole fleet of ships while you're still dicking around building one Orion capsule?"

Elon has the potential to commercialize deep space at "flat" (not cost-plus) prices, just as he has already commercialized launch to LEO and GEO. This has implications far beyond Mars. If NASA can be convinced to switch to this model, we'll be in a world where NASA's mission planning office is a guy with a telephone asking for quotes. "We want to send 100 tons to Europa. Please RFQ."

Bare Launch Costs
Although he glossed over it quickly, the projected launch costs per ton to LEO for the BFR are about $150/kg. That's a great number. Cheap commodity transport is what allows globalization to work. Even if the BFR never sends a colonist to Mars, sending paid cargo to Cis-lunar space at that price would be awesome.

ISRU/Refueling on Orbit
There is no opening up the solar system (or even the Low Earth Orbit) as long as we need to take all the fuel for the return trip in the initial launch. Real space ships refuel in orbit and at their destination. A real space-faring civilization has fuel and supply depots throughout the solar system. NASA has never even tried to build this. If SpaceX succeeds in this, humanity's future in space is bright.