Archive for September, 2016

An open letter to SpaceX

I applaud Elon Musk and his company SpaceX for getting the world interested in space travel again. Having been born in the 80’s, I grew up thinking about space travel and planetary colonization during a time when few others were. For those of you who haven’t caught up, Yesterday, Elon Musk gave a great 2 hour speech about SpaceX’s plan for Colonization that you can view here:

I’ve got a handful of ideas about why Venus is actually a better target for colonization, but those go beyond the scope of today’s post so I’ll save those for sometime soon. Today, we’re going to talk about Mars.

First things first, let’s talk about what Elon got right. Right now we don’t go to space often because it’s ridiculously expensive The mind-numbing cost of space travel comes from 2 real sources:

  1. Development costs. When you spend billions of dollars to develop an aircraft or iPhone, you’re spreading those costs out over thousands or millions of units. Boeing spent 3.7 billion dollars to develop the 747, but then proceeded to build about 1500 of them, or about $2.5 million per aircraft. Compare that to the Space Shuttle which was developed at a similar time. Nasa spent $5.7 billion dollars on research and development, then built 6 of them. Each orbiter therefore, had about $950 million of R&D built into their cost. If we’re going to mars at scale, we need to build a lot of spacecraft to go back and forth.
  2. Hardware reusability. Most of our government-funded rocket designs are based around weapons. Missiles don’t need to be reused. They are launched out of a silo or submarine, fly to their target, and ruin a bunch of people’s days. They don’t then turn around and come home to stock up and spoil more people’s days. —When we developed our space program, we decided to utilize existing designs to reduce development costs, though we pay for it in reusability. As Elon so brilliantly put it, if we used an airplane once every time we wanted to go from Los Angeles to Vegas, the seats would be a half a million bucks.

While Elon’s ambitious plan seems sound on the surface, I think that SpaceX’s plan leaves much to be improved. I’m going to focus on 2 key points:

1. How can development costs be better allocated and possibly even reduced? Are there opportunities to use existing technologies?
2. What are we going to do once we get to Mars? SpaceX tells a great story about how to get there, but offers little in the way of things to do once there.

How can development costs be better allocated and possibly reduced?

SpaceX’s transit plan strikes me as roughly analogous to the Direct Ascent proposals favored by Nasa during the early planning stages of the Apollo program. The general idea was that you could trade engineering complexity and efficiency for raw power to reduce the development costs of the moon missions.

The NOVA Rocket had a first stage that called for 13.5 million pounds of thrust, or double that of the already gargantuan Saturn V! We obviously never undertook such a design; mainly because it’s stupid and the rocket equation is a cruel whore when you factor in atmospheric drag, high gravity, and low specific impulse environments near the earth’s surface.

Instead we decided that it would be smarter to go into Earth’s Orbit, spend a little time catching our breath, getting the gear ready, and maybe having a wank before blasting off for the moon. Each rocket would be designed for their specific part of the journey. When we got to the Moon, we would not then slow down and deorbit the entire fucking spaceship onto the moon like idiots. We would be smart and just drop off a little pod specifically designed to chill on the moon for a few days, then go back and meet up with the return stage to go home. 3 separate rockets (well 5, but 2 of them were to get into orbit and 2 were used to get up and down from the moon) to do 3 separate jobs.

Applied to Mars, I think there should be 3 spacecraft systems that I will detail below:

  1. An earth ascent/supply system that resupplies a mars “bus,” spacecraft. This could utilize rockets already in existence. Development cost: Free 99! The idea is that you’d load up a bunch of fuel and gear using already existing launch hardware. If SpaceX’s Falcon rockets continue to lower the cost of access to LEO, I’d imagine that we could launch a bunch of shit up there pretty cheaply.
  2. A purpose-built spacecraft that does nothing but go from Mars to Earth orbits. Rather than having to engineer for atmospheric reentry on Mars and Earth’s surfaces, you’d do away with all kinds of heat shields and aerodynamic surfaces. You could instead spend that weight on proper radiation shielding for the crew and centrifuges to keep passengers happy and healthy for the trip to and from Mars.
    Secondly, as I already stated: low specific impulse propulsion systems suck. We have to use them close to the earth’s surface due to atmospheric drag and gravity, but there is nothing to stop us from using low-thrust, high specific impulse propulsion methods in space. A solar or nuclear powered VASMIR system strikes me as ideal. — For those of you who think I’m crazy wanting to launch a nuclear reactor in space, I’m going to come back to that point later but for now just bear with me.
    This spacecraft would be used to shuttle crew and supplies to and from Earth and Mars orbit. I would be permanently in space. For those of you who have seen The Martian, this would be a rough equivalent of the Hermes spacecraft. It was in that movie because the author of the book is fucking brilliant and tends to know a bit more about orbital mechanics than Elon does, but I digress.
    Another benefit of this design is that if you build a lot of them, you could use them as hops on a wireless network. Right now the internet on Mars is slower than dialup. This is because you need a ridiculous amount of energy to transmit high-bandwidth data to mars and back. If you shorten the distance that data needs to travel, then simply repeat it from hop-to-hop, you can massively improve data transfer rates between planets. I can’t go 30 minutes without internet. If we’re going to be transporting thousands and eventually millions of people between planets, you’re going to want a reliable communication network between them.
  3. You have a reusable, Single Stage to Orbit ascender/lander that meets up with the “bus” spacecraft to shuttle people and supplies to and from Mars. Yes I said from mars too. If we’re going to set up a colony and eventual cities, being able to exchange goods and services between planets is essential. This isn’t a charity folks, we’re not spending hundreds of billions of dollars to send people to Mars and not get some kind of return on our investments. I’ll get to what we’ll be shipping back in a bit as well.

What kind of cool shit can we do on Mars?

Now that we’ve tackled the bits about getting to and from Mars in a more efficient manner, let’s talk about what we’re gonna do once we’re there. First of all, let’s get something out of the way. Mars is colder and more inhospitable than a Chicago winter. The atmospheric density is 1% that of earth. You need a pressure suit to walk around. Furthermore, Mars does not have a magnetic field protecting us from solar radiation like how the earth does.

All in all, the planet needs a few small changes that I think could be done in maybe 15-20 years’ time. For those of you who are shouting that terraforming an entire planet takes way longer my response to you is “my ass.” We’re currently terraforming the Earth at an unprecedented scale, most of which has occurred in the past 50 years. Mars is much smaller, it’s not gonna take that long folks, just trust me.

Elon has (perhaps not so) jokingly pitched the idea of carpet bombing the poles to heat up the surface, but the radioactive fallout would probably make the whole planet inhospitable. My solution involves using nuclear energy as well, but perhaps a bit more responsibly.

I think the best course of action would be to put LFTR reactors at the poles then run the power grid in ridiculously high voltage DC lines wrapped around the planet so that we could make our own magnetic field to shield us from solar radiation. This has the added benefit of preventing solar wind from stripping away all of the new additions we’re planning to make to the atmosphere. If you’ve got about 2 hours of time on your hands, watch this video to learn a bit more.

Nuclear Power on Mars? Are you fucking kidding me?!

As much as I admire Kirk’s evangelism of LFTR designs, these reactors are not without their flaws in earth applications. These flaws on Mars, however, are huge benefits and I’ll explain why below.

  1. The waste heat from the reactors on each pole would help to sublimate the poles so that we could have a thicker atmosphere. Mars’ colder surface also has the benefit of making electricity production significantly more efficient than on the earth due to the greater temperature differential. Sublimating the poles would also have the benefit of slightly decreasing the albedo of the planet. If oceans were to develop from this, a significant decrease in albedo would occur
  2. The waste heat would also melt a significant portion of the ice, giving us water. Great for agriculture, great for loading it full of algae so we can work on getting ourselves a breathable atmosphere. Great for all kinds of shit really. Also, the water on Mars is a bit different than that on the earth. Specifically, it is about 6 times richer in deuterium than the water is here on Earth. Deuterium is used in all sorts of scientific and industrial applications, which we can ship back to the earth for profit.
  3. The waste products from LFTR reactors are a bit different than those of the asinine reactors we use on the earth. Aside from being inherently safer, they don’t *really* create nuclear waste in the same way that our current reactors do. Fission byproducts include
  • Non-fissile Pu-238, great for radioisotope power generators
  • Iodine-131, used in a massively effective thyroid cancer treatment that is unfortunately very difficult if not impossible to come by due to its scarcity on the earth.
  • While we’re on the topic of cancer treatments, Thorium-229 and Bismuth 213 are additional byproducts
  • Xenon-135 and Krypton-85. Xenon-135 has a short half-life of about 9 days and needs to be pulled from the reactor as it’s a strong neutron poison, and Krypton-85 is a big reason we don’t build LFTR reactors on the earth: it needs to be stored as a compressed gas for over a decade. HOWEVER, it is also an ideal fuel for the kinds of ion engines that I envisage our “bus” spacecraft using. These containers could be easily shipped off-planet to be used as fuel for interplanetary travel.

Thorium is readily available and relatively cheap to mine in the crust of Mars so you wouldn’t even need to transport dangerous nuclear fuels from Earth to Mars. You would need to bring a few kilograms of U-233 to seed the reactor, however these could be put into hardened containers designed to survive a rocket explosion.

Ok, so what’s next?

I want to touch a bit on further terraforming efforts as nuclear power stations and a power grid is not the only thing that we need to do in order to facilitate terraforming efforts. Even if we sublimate the entire volume of gas on the poles, an aggressive estimate suggests that doing so would yield no more than a 30-40% increase in atmospheric pressure. We might find that there are a ton of stored gas and dry ice pockets throughout the planet that would also boil off when we heat the surface of the planet, but even if we doubled the atmospheric pressure of Mars, we’d still want a pressure suit or at the very least, a mechanical counter pressure suit with a helmet. Doubling the surface pressure of Mars from 1kPa to 2kPa is still well below the Armstrong Limit of 6.25kPA for an unprotected human. We’re gonna need a lot more gas. 3 times as much, in fact.

It’s a bit is a stretch, but given the abundance of Deuterium detected in the water ice on the poles, the abundance of river beds, and the fact that fossil evidence on earth gives evidence that single-celled life appeared on the earth almost immediately; there’s a possibility that Mars once hosted a large amount of life.

If it is discovered that there was once life on mars, it stands to reason that there are probably massive amounts of fossil fuels in the form of coal and oil reserves. Depending on how successful we are at producing large quantities of oxygen, we should begin burning them immediately to produce power to further heat up the planet and deposit more CO2 into the atmosphere. We could probably have a breathable atmosphere in under a century given that’s all it took for humanity to massively heat up the earth.

If for whatever reason fossil fuels are not forthcoming, we could probably start by redirecting comets from the asteroid belt. We’d want to start significantly after we’ve already begun thickening up the atmosphere or we’d have some real trouble slowing them down enough to hit the surface in a manageable way, but it’s a thought.

So there you have it; a transit system, an energy source, trade goods that could be shipped back to the earth to pay off the enormous investment, and you’ve got a bi-planetary economy. The effort would create countless highly skilled jobs both on earth and Mars. It should also be noted that adding such significant trade routes to the ones we currently have on the earth, we would be significantly increasing the size of not just thew world economy, but the economy of humanity.