Space – Getting To Mars Part 3: Propulsion

We kicked off my series on “Getting to Mars” last time with a look at Orbital Mechanics – showing that the physics of getting from one planet to another can be mostly explained with a stapler, a pen, and Kristen Wiig looking unimpressed. This time we’re looking at the propulsion systems that we’ll use to get to Mars.

Of course because every armchair expert has their own pet propulsion project they think is critical to the future of space exploration, this is probably the article I’ll have to delete the most hate-mail for. That’s right – I don’t even read your unsolicited and poorly-spelled bullshit before deleting it, but thank you for reading all of mine! And if you haven’t already figured it out this is also the article you’re probably going to get me at my snarkiest, because there are three phrases I hear on a fairly regular basis that genuinely get under my skin and strangely all three are connected in some way to spacecraft propulsion…

#1 “Space is hard” – The lame catch-cry of everyone that’s just watched a spacecraft disintegrate in a “rapid unscheduled disassembly“. Don’t whinge that space is “hard” – find the cause of the problem and learn from it. Space isn’t hard, it’s just unforgiving of screw-ups. Screw-ups like when someone puts in a gyroscope upside down on a US$1.3 billion rocket launch, or when someone else loses a Mars probe because it was built by the world’s biggest aerospace contractors in the only country besides Liberia & Myanmar still fighting the Metric system.

#2 “It’s not rocket science” – The sarcastic accusation that something you’re struggling with isn’t really that difficult. You know, instead of helping you, someone will suggest you’re an idiot. Here’s something for all of you unhelpful jerks: Rocket science is not difficult. Rocket science can be explained with literally ONE equation (aptly called the “Rocket Equation”) that’s not even remotely complex. Ready for it?
Where \Delta v\ is the change in the spacecraft’s velocity, v_{\text{e}} is how fast things are being shoved out the back of your spacecraft (eg. the rocket exhaust), and you multiply that by the natural logarithm (\ln ) of your spacecraft’s initial mass (m_{0}) over it’s final mass (m_{f}). You can also express the same equation in terms of specific impulse, but if it’s all feeling too complex just remember you go faster if you throw bits of your spaceship out the back really fast to make it lighter.

Rocket science is not difficult, however rocket engineering is ludicrously complex and exceptionally challenging*. So next time you decide to be an obnoxious and holier-than-thou wanker to someone trying to do something they’re struggling with, how about at least getting the terminology right?

*For why I still refuse to say rocket engineering is “hard”, see point 1 above

#3 “We need to develop better solar electric propulsion to get to Mars” – I’ll get to why you’re what’s wrong with the space industry a little later, but for now lets just say you’re a piece of shit and I can prove it mathematically.

Spacecraft propulsion can be broken down into two big categories: Thermodynamic (using heat to move gas) and Electrodynamic (using electricity/magnetism to move gas).


This category is mostly the kind of spacecraft propulsion everyone is familiar with: rockets. Absolutely no one is doubting that rockets look super cool. They’re also dangerous, wasteful, noisy, and prone to going boom because of the most tiny and obscure things… like super-chilled liquid oxygen turning solid on your carbon-fiber wrapped helium tanks.

Rockets are also ridiculously expensive and absurdly inefficient at getting things to space. The Saturn V that launched men to the Moon* weighed nearly 3 million kilos on launch, but only 5,560kg of that was left by the time the Command Module splashed down in the ocean. To put it in context, 0.185% of the original rocket’s mass came back to Earth and the other 2,964,440kg was either burnt as fuel, dumped in the ocean/space, or left on the Moon. Considering each Saturn V launch cost about US$1.16 billion in 2016 figures, that’s a whole lot of specialised and expensive stuff to be just throwing away.
* Don’t even start with me Moon Hoaxers – I will destroy you

I’d talk about how NASA’s “Space Launch System” is supposed to (eventually) be more powerful than Saturn V… buuuuuuuut since SLS & the Orion capsule are basically the worst parts of the Bush-era Constellation program that have already cost US$18 billion and are now projected to reach US$35 billion in 2025, at this point it really looks like it’s just a pork-barreling jobs program for a bundle of US Senators through the old conservative aerospace manufacturers. A jobs program which is also takes funding away from real exploration opportunities (like the underfunded Commercial Crew Program) to build a rocket that’s going anywhere. #NotEvenSorry

I currently have a bet with a fellow space geek about SLS: I’m convinced it will be cancelled before it ever flies, whereas she thinks it’ll fly once before it’s cancelled. The loser has to buy the other a ticket to Mars aboard this…

Did you see that gigantic rocket flying itself back to the launch pad to refuel and launch again? That’s SpaceX’s “Interplantary Transport System”, and once it’s up and running in the 2020’s there will be several of these taking 100 to 200 people to Mars every few years for about US$200,000 each – return trip included. They can afford to talk about sending people to Mars and back for less than the median cost of a house in the US (or 1/4 of a house in Sydney) because they’re not dumping most of their rockets into the ocean every time they launch – they’re landing them, refueling them, and launching them again. Building better rockets and not throwing most of them away after a launch means the cost of getting stuff to orbit has decreased dramatically in recent years.

We’ve never used rockets for their efficiency though – we use them because they produce a huge amount of thrust. If you have to get something from the ground into Low-Earth Orbit, it needs to push through the air with enough raw power and velocity to break free of the atmosphere and start falling around the Earth with enough velocity not to hit it again. Right now the only thing we’ve got that can push hard and fast enough to reach orbit is rockets, and no matter whatever weird propulsion system other folks might be dreaming about this is also the only way we’re going to get to Mars in the next 15-20 years*.

*Bring it on Solar Electric Propulsion people – I’ve got your number at the end of this article.

That’s not to say all rockets are the same though – we’ve got all sorts of different ways of making things go boom to get somewhere fast:

Solid Rockets – Basically really big and complex versions of the little gunpowder rocket engines you can buy at a hobby store. They’re cheap, powerful, and easy to make – perfect for launching things like cargo and probes into space.

It’s probably not a great idea to use solid rocket boosters on anything carrying people though – once you light a solid rocket you can’t stop it burning if something goes wrong… like when one on the space shuttle burned through an o-ring and into a 760,000kg tank fuel of rocket fuel, which then exploded and killed seven astronauts. But NASA is planning to use solid rocket boosters again with the crewed SLS (test fire pictured above). So, you know… YOLO.

Liquid Rockets – Pumping flammable liquids into a chamber and having them explode in a specific direction. While the Chinese were the first to get serious about solid rockets back in the 1200’s, it wasn’t until the 1900’s that a guy called Robert Goddard started to set fire to liquids to push rockets around. Unfortunately the US’s scientific community and the New York Times just made fun of him for suggesting rockets could work in space.

Correction the New York Times published 3 days before Apollo 11 launched (on liquid rockets) to the Moon… and 24 years after Goddard had died.

Fortunately some people payed attention to Goddard’s research into liquid rockets. Unfortunately those people were also the Nazis, who then used that research to bomb Europe with these:

Liquid rocket engines are way more complex than solid rocket engines essentially because the fuel is sloshing around and needs to be pressurised through tanks & fuel lines for them to keep flying. Going back to my earlier “rocket science is easy, but rocket engineering is hard” – the national security restrictions imposed by each country on who can work on their rocket technology often has little to do with the rocket itself, and is almost entirely about protecting the technology behind the turbopumps that push the fuel and oxidiser at high speed & pressure into the engine bell.

Liquid rockets generally get broken down into two further categories depending on their fuel too. Bipropellants are what you see in a usual rocket launch where an oxidiser (usually liquid oxygen) and a fuel (kerosene, liquid hydrogen, methane, ect) burn to produce thrust. Monopropellant is a single liquid that ignites when it touches a catalyst, and is often used once you’re in space to turn your spacecraft around or give it a gentle push. It’s also usually made of hideously toxic, carcinogenic and explosive liquids like Hydrazine, that apparently smells like fruity-ammonia if you live long enough to tell someone.

Hybrid Rockets – A surreal mix of a solid and liquid rocket. The most obvious and well-known example of a hybrid rocket powers this:

Virgin Galactic’s Spaceship Two

Hybrid engines have a liquid/gas oxidiser that runs through channels in the solid fuel to burn it. They avoid the complexity of liquid rocket engines, and unlike a solid rocket you can stop them once they’re lit by cutting off the oxidiser supply. The downsides are they’re not as efficient as solid or liquid rockets, and most of them are filthy polluters. The fuel going into hybrid engine in Spaceship Two has been changed a lot, but it’s usually nitrous oxide burning rubber. So pumping soot directly into the upper atmosphere isn’t exactly fantastic for things like Global Warming…

Nuclear Propulsion – Launching tonnes of hot, radioactive material into space because it’s really good at getting you places fast… provided it doesn’t explode on the way.

Now I’m only including this because it is a form of thermodynamic propulsion, people have talked about for more than 60 years, folks like NASA & the Soviets have designed entire working systems around it… and even at it’s absolute safest it’s still fairly insane.

Nuclear rockets are outrageously powerful – even the most basic designs are twice as powerful as what’s possible with a chemical rocket. There are dozens of different (theoretical) varieties, however only two have ever been developed properly: NASA’s NERVA and the Soviet Union’s RD-0410. NASA actually had the closed-cycle NERVA XE flight ready and deemed suitable for a Mars mission in 1969, right before NASA’s funding was cut because it was clear the US was going to win the race to the Moon. Both the NASA and Soviet systems still involved using a flying nuclear reactor to super-heat hydrogen in space, however they were designed to be comparatively safe “closed cycle” systems.

I say comparatively, because you have to compare it to the other crazy shit other people were suggesting in the 1960’s. Fun things like “open cycles” designs that used weapons-grade radioactive material and deliberately spewed out clouds of radioactive exhaust.

See the bit saying “Uranium 235 T~55,000 K” leading to an open nozzle? Because fuck everyone else on the planet, right?

Then there’s the folks who designed Project Orion, who clearly felt the only thing better than using a nuclear reactor in space would be to use actual nuclear weapons. Project Orion was about literally firing a nuclear weapon behind your spaceship to propel it in the other direction: for anyone who’s ever played Quake or Team Fortress 2 this is basically a rocket-jump but with a nuke.

We’re not talking about just one nuke either: the idea was to have one going off every second, and some of the interstellar designs called for a spacecraft 20km long that carried 300,000,000 1-Megaton nuclear weapons, or “pulse units” as they were so eloquently renamed. Strangely enough Project Orion pretty much ended when most of the world signed the “Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water” (aka the Partial Nuclear Test Ban Treaty) in 1963.

The fever dreams of Dr Strangelove

Chances are we’ll need some sort of nuclear propulsion in the future to take humans beyond Mars though. Jupiter barely gets 4% of the sunlight the Earth does, so the diminishing light from the Sun makes solar power a lot less viable. It’d also be a great way to reduce the nuclear stockpiles we have, and there’s even some semi-reasonable arguments for taking small nuclear power plants to provide electricity to a colony on Mars – the big issues are obviously what do you do with the waste and what if something breaks?

Nuclear propulsion isn’t completely insane… but do we need to take the risk, when we can get to Mars just fine using conventional chemical rockets? No. 

Do you know what else we don’t need to get to Mars? Solar Bullshit Electric Fucking Propulsion.


Maybe you’ve heard on the news about some crazy space propulsion system that uses lasers, ions, or something else that sounds really complex and weird. Chances are it’s either a solar sail (which are slow but cool in their own “Star-Surfing with Sagan” kind of way) or you’ve heard about some variant of an ion drive (which are also slow but cool in their own “Star Trekking with William Shatner” kind of way too).

Ion drives are not some far flung science-fiction fantasy though: Harold Kaufmann built the first ion thruster in 1959, the Russians launched their own variant (known as a Hall Effect Thruster) on a satellite in 1971, and almost all modern communication satellites use some form of ion drive for “station-keeping” – correcting for variations in Earth’s gravity to maintain a highly precise “geo-stationary” orbit.

Essentially ion drives use electric fields to accelerate a gas (usually Xenon) out an exhaust at incredibly high velocities to produce a tiny thrust. The high exit velocity (aka “Specific Impulse”) means ion drives are insanely efficient and capable of reaching much higher maximum velocities than any rocket ever could, and there’s been some really exciting improvements… but because ion drives only throw out only a tiny bit of gas (eg. roughly the same amount of force you feel blowing on the back of your hand) they’re also incredibly slow to accelerate up to those high velocities.

How slow? NASA’s Dawn mission has three Xenon ion thrusters capable of 90mN of thrust (about the same force as the weight of a postage stamp) that can accelerate the probe from 0 to 100km/hr over four days.

Ion drives absolutely have their place, but no matter what bullshit spin some of the old aerospace players might try to pull that place is not getting people to Mars. Ion drives are improving, but unless VASIMR unexpectedly gets a demo flight and proves it actually works electrodynamic propulsion simply won’t be powerful enough to shorten the trip to Mars for humans any time in the next few decades. Especially if you’re only using solar power.

Improved ion drives that run on solar power will be really useful however for… getting communication satellites from Low-Earth Orbit into a Geo-stationary orbit.

Here’s a fun fact: the global satellite communication industry generates over US$200 billion in revenue each year, and makes up nearly 2/3’s of the entire space industry. Reaching Low-Earth Orbit (160km to 2000km altitude) with a rocket is relatively simple, however getting to Geo-stationary orbit (~36,000km and where almost all large communication satellites need to be placed) is much harder, requires far greater velocities, and usually needs an additional stage on the rocket. This extra velocity and additional staging brings greater risks of things going wrong, so naturally launching something to such a high orbit is also a lot more expensive.

So if telecommunication companies can launch new satellites to a much cheaper Low-Earth Orbit and then use solar powered ion drives (aka “Solar Electric Propulsion” aka “The bane of my existence”) to slowly shift new satellites up to geo-synchronous orbit over several months, they’ll save literally billions in launch costs alone.

Are you bored by this yet?  

No shit – the satellite communication industry is boring, but it’s also really big money. Do you know what is not boring, but also means risking lives for something that won’t make anywhere near as much money? SENDING PEOPLE TO MARS.

Which is why there’s a huge amount of money and research going into solar electric propulsion at the moment, and why I roll my eyes obnoxiously at everyone who tells me it’ll “help with NASA’s #JourneyToMars”. Because they either don’t understand how weak solar electric propulsion currently is, or they’re trying to bullshit me and others into believing a technology being developed to reduce the cost of deploying communication satellites around Earth will somehow get me to Mars.

I’m happy to be proven wrong on all of this, and I’m certain in the far future we’ll use ion drives to zip between Earth and Mars. I’m even sure some of them will even use solar power. They’ve been trying since 1971, but maybe Ad Astra will finally get somewhere with VASIMR afterall. Maybe the EM Drive will be completely validated and change everything. But don’t tell me we to need to pour billions more into solar electric propulsion research to get to Mars – chemical rockets have been getting things there just fine for decades.

In the meantime, Mars One was founded with the express purpose of permanently colonising Mars, and SpaceX was founded with the express purpose of establishing a sustained human presence on Mars too. Do you see either of them talking about needing further research into solar electric propulsion?
No? Just using conventional liquid rockets you say?

Funny that…


Space – Getting To Mars [Part 2: Orbital Mechanics] or: How I Learned To Stop Worrying and Love Gravity

There’s a common misconception among the general public that physics is boring, yet nothing could be further from the truth. As a physicist I can say with confidence physics is awesome, it’s just physics teachers that are boring. I hesitate to say all physics teachers are boring, because I’ve met a few really exceptional ones… but there’s also been plenty of others who some how manage to suck all the colour and joy out of the incredible relationships that govern our universe. So with this in mind we’re going to tackle arguably one of the most abstract, mathematically complex, and potentially boring concepts in Newtonian physics – Orbital Mechanics – and we’re going to make it awesome instead.

Also I don’t mean in that fake-smiling “YAY!!! ISN’T THIS FUN KIDS?!” way where you’re desperately trying to convince yourself and others that your entire life’s work means something, while your soul slowly crumples inside as you fight the creeping existential dread that the universe is unloving and ambivalent to your existence and everything you do… I mean in a “Holy crap the universe is ridiculous, awful and weird, and I need to know more!” equation & jargon-free kind of way to explain how we’ll get to Mars.

Which I think we can all agree is a lot more fun than reading Nietzsche and embracing nihilism over a cup of tea.

Firstly some basics. If you want to go anywhere in space, you either need to a) increase your spacecraft’s velocity using a rocket or other propulsion system (we’ll cover propulsion in the next article) for a little to increase the size of your orbit and coasting through space as gravity to pulls you around on a curved path, b) have a ludicrously powerful propulsion system to brute force a straight line to wherever you want to go, or c) travel at 88mph and use 1.21 Gigawatts of energy to tear a hole through the fabric of space-time and pop out wherever/whenever you like.

Because we don’t yet have anything even remotely powerful enough to brute force a straight line through space, and neither Doc Brown or Sam Neill have been opening any portals to hell recently, that leaves firing a rocket for a bit to increase the size of our orbit and letting gravity do the rest of the work. The most fuel-efficient way to do this is called a “Hohmann Transfer”, where you increase your velocity just enough to reach where you’re going. When you’re trying to get from Earth to Mars that means burning your rockets when your spaceship is closest to Earth (to get the most out of the rocket thrust) and after coasting for 8.5 months you arrive at Mars at the slowest point of your new orbit.

Burn your rocket when you’re travelling fastest at #1 (Earth), slow down as you travel along the yellow line, arrive at #3 (Mars) when you’re at the slowest point of the new orbit

But “fuel-efficient” is slow and boring – the space exploration equivalent of having sex while listening to Enya. It’s fine if you don’t have anything better to do with your afternoon – or if you want to launch cargo to Mars that can take 8.5 months to get there – but the longer you spend in deep space the more cosmic radiation (and Enya) you’re being exposed to. Humans also need food and water and oxygen and a bunch of other nonsense robots and cargo don’t, so Hohmann transfers aren’t ideal for sending humans to Mars unless you really hate them.

Getting to Mars in less than the 8.5 months means we have to leave faster. Sounds simple, but this gets ridiculously complicated really quickly. The three things to remember though are the more you accelerate:

  1. The straighter you’ll travel and faster you’ll get there (which is awesome)
  2. The more you’ll have to de-accelerate at the other end (which sucks – you now need extra fuel to slow down, or take a mega heat shield to slow down using Mars’s atmosphere and risk skimming off it and into the cosmic abyss)
  3. The exponentially more fuel and energy you need (Newton’s 3rd law: to go somewhere you have to throw stuff in the opposite direction)

We’ll talk more about propulsion systems in the next post, but right now using traditional chemical rockets the quickest we can get to Mars is about 6 months. Which looks something like this:

Interplanetary transfer for the Mars Odyssey probe in 2001

Obviously you also don’t aim for where Mars is when you’re launching from Earth, because it won’t be in the same place you were aiming for 6 months later. Like throwing a water-bomb at a toddler you aim ahead to where your target will be in the future, letting gravity and the easily predictable path of a planet or under 5 do the work for you.

Because Earth orbits the Sun once every 365.25 days and Mars orbits the sun once every 687 Earth days*, they only line up for this kind of transfer once every 22 Earth months.

*Mars has a “day” of 24 hour and 36 minutes called a “Sol”, so 1 year on Mars is 668.6 sols

Alright, enough already

There a couple of other little tricks of gravity we can also use to get to Mars quicker and with less fuel too, namely Orbital Slingshots and Ballistic Capture.

Orbital Slingshots AKA “Gravity Assists” AKA “Big Thing Make Spaceship Go Fast”

Turns out you can actually use an entire planet to speed up your spacecraft if you’re willing to swing in close enough. The gravitational attraction between a planet and a spacecraft doesn’t just move the spacecraft – it also moves the planet a tiny fraction too! So by flying up behind a planet as it orbits and letting gravity swing your spacecraft towards it you’ll slow the planet down (increasing it’s “year” by a few nanoseconds) but massively increase the velocity of your spaceship!

The last diagram, I swear

This is actually what they use in The Martian to get the Hermes back to Mars and save Mark Watney. While Donald Glover is being a mentalist with a stapler in a NASA boardroom, he’s describing an especially powerful orbital slingshot. The speed boost the Hermes gets swinging around Earth is the reason they can get back to Mars so quickly, but it’s also why they’re going so fast at the other end.

Kristen Wiig will have none of your swingline shenanigans

Ballistic Capture

Recently we’ve discovered another way to get things from Earth to Mars that doesn’t require you waiting nearly 2 years for an alignment or having Sam Neill take you through a portal to Hell… but it’s even slower than the “Enya-Space-Sex” Hohmann Transfer. This “Ballistic Capture” approach involves getting just close enough to a planet or moon that it’s gravity slowly pulls your spacecraft into it at low velocity without needing any extra fuel to slow down. It’s just like knocking a pool ball towards a pocket and having it stop right on the edge: it’ll either roll in on it’s own after a few seconds, or you give the table a little bump to help it in.

Ballistic capture was used by the Japanese probe “Hiten” to orbit the Moon in 1990, but until recently it was believed that Mars was too small and too far away for ballistic capture to work. Some clever folks with a super computer recently worked out though that you can launch towards Mars anytime as long as you don’t mind taking up to a year to get there. For a human crew this would be like having sex to Enya playing at half tempo, so you might prefer the trip through actual Hell with the Event Horizon instead.

Before you realise Sam Neill is playing Enya through the PA too

For someone like Mark Watney though – slowly starving on Mars because his potato crops were suddenly freeze dried – this would have been pretty handy. Building a new probe full of food, testing it properly (rather than just glancing at it and saying “Yeah mate, she’ll be right”) and launching it on a 1 year trajectory using a ballistic capture would have been considerably quicker and safer than the mentalist orbital slingshot the Hermes crew do in the film. Although I guess staying put and eating potatoes for a few more years isn’t as “Hollywood” as:

  • Surviving 20 Gs while riding into space on a rocket with the front half of the capsule removed, using a canvas tarp over the holes… for decoration?
  • Explosively decompressing the pressurised living area of an inter-planetary spaceship (full of critical life support systems that can’t operate in a hard vacuum) to slow down
  • Instantly cutting through the dozen layers of rubber, canvas, Kevlar and Mylar in a spacesuit glove, then using the minuscule pressure in a space suit (less than what’s in a football) to “Be Ironman” and fly to safety…

Me during the last 10 mins of The Martian

So there you have it: orbital mechanics that’s awesome and not lame/boring. Obviously there is so much math to dig into if that’s what gets you off, and I’m not one to kink-shame: go and get wild solving three-body problems or dig out on the crazy equations describing Lagrange points, gravitational keyholes, Halo orbits, Lissajous orbits and Horseshoe orbits, or Hill spheres… if that’s your thing.


Space – Getting To Mars [Part 1: Overview]

For the last few years I’ve structured my school visits and public talks primarily around answering questions about the Mars One project, rather than lecturing. For an average 90 minute school visit for example I’ll usually only speak for the first 10-15 minutes – with plenty of images of Mars and no text on the slides – before spending the next 75-80 minutes answering every question under the Sun about life on Mars. School visits in particular are incredibly entertaining, mostly because kids have absolutely no shame and no chill – they will ask absolutely every obscene thing you could ever imagine, while literally bouncing up and down in their chair with excitement, and I have to try to honestly answer their question about how sex, death, shitting, and/or cannibalism will be different on Mars than it is on Earth while their teachers look on in horror.

“Mr Richards, what would you do if there was an ACCIDENTAL fire in your Mars house?” *giggles*

When people hear about Mars One though, their questions almost always focus on what it would be like a) leaving Earth behind, and b) living on Mars without any prospect of coming back. Besides “how long will it take to get there?” though, I don’t usually get a lot of questions about the journey to get there itself. Kids want to know how you shit in space, and they understand the idea of living in a special “house” on Mars… but drifting for months through the inky darkness of interplanetary space to get to your new home is a concept so far removed from their regular lives they don’t even know where to start with questions.

And if kids won’t ask questions about the trip to Mars, you can be damn sure that adults won’t… unless they’re a massive space geek, in which case it’s 50/50 if they’re asking a question because they’re really excited about what you’re doing, or if they’re trying to “correct” you to show off their own knowledge.

So with all of this in mind, I’ve decided to write a series on how we’ll actually get to Mars. I’ll inevitably follow it up with another series on how we’ll live on Mars once we get there, but there’s definitely a huge knowledge gap in comprehending just how difficult (but perfectly achievable) the journey itself is.

Orbital Mechanics & Interplanetary Transfers

Contrary to what most kids (and plenty of adults) might think, you can’t just point your rocket at Mars and hit “GO!” (as awesome as that would be). With Earth and Mars orbiting the Sun at different distances, inclinations and orbital velocities; going from one to the other involves a lot more swinging and looping than people expect, and orbital mechanics has a great way of messing with people’s heads.

The short story is it will take us roughly 7 months to get to Mars, but because of the alignment of Earth, Mars and the Sun we can only launch things to Mars every two years or so. I can already hear the angry space geeks mashing their keyboards at that sentence alone… but if you can hold off for a few weeks from sending me hate-mail filled with delta-V equations and screaming in all-caps about “BALLISTIC CAPTURE”, I’m going to delve deep into orbital mechanics. As always I’ll be writing equally for comedy AND science-communication, so don’t panic if you’re the type who doesn’t break out into an excited sweat at the sight of a Hohmann Transfer equation – I”l be aiming to help you understand why there’s no straight lines when you’re trying to get anywhere in space, but without you needing to become a full-blown pocket-protector-wearing nerd in the process.

Launch Vehicles & Propulsion

There’s no shortage of folks gushing about how you’ll need a “big rocket” to get to Mars (don’t talk to me about SLS, I’m only going to sigh at you) but there’s a lot more to rockets than just “burn lots of fuel really fast to make things go up”. Payload fairing size, solid vs liquid fuels, payload harmonics, staging, crew/cargo separation – it all gets pretty complex pretty quickly. I cringe any time someone sighs and tells me “Space Is Hard”, but using rockets to get places is definitely expensive, risky, and utterly unforgiving if something goes awry.

It’s also not just the “getting out of the atmosphere without being ripped apart” bit you need to worry about either – between ion engines, solar sails, Neumann Drives and nuclear propulsion (if anyone mentions “Solar Electric Propulsion” I will scream at you), there is a mountain of different ways to move between planets without an atmosphere to contend with that are a lot more efficient than just firing up a hypergolic rocket like the US used in the Apollo program to get to the Moon (DO NOT EVEN START WITH ME, MOON HOAX PEOPLE. I’M ALREADY PISSED OFF ABOUT SLS AND SOLAR ELECTRIC PROPULSION – I WILL DESTROY YOU).

Life Support & Psychology

If you’re putting people in an aluminium can and launching them for 7 months to live on a cold, desolate planet for the rest of their lives…. you kind of want them to survive the trip. While there’s still a lot of discussion about the design of Mars One’s transit habitat, we already know it will face unique challenges that nothing rated to carry humans in space has ever had to contend with. Operating somewhere between the space shuttle (which never spent more than 18 days in space) and the International Space Station (which has so far spent more than 18 years in space), the Mars One transit habitat will need to keep four astronauts fit and healthy during the trip to Mars, but once it reaches Mars orbit it also won’t ever need to be used again… so life support systems that are reliable for 7+ months, but also can’t be repaired with critical supplies from Earth.

There’s also that little factor of how do you keep the crew from going bonkers and opening the airlock – preferably by not taking a suicidal British botanist for starters. While I’ve already talked about how to use Ernest Shackleton’s approach to crew selection as a template when selecting a Mars crew, the psychology of space exploration is a particularly fascinating topic generally so get ready to be bombarded with discussions on Breakaway Syndrome, the 3/4 Factor, the Overview Effect, and Facebook use during Antarctic over-winter studies!


*sigh* I’m only doing this because there is a ridiculous amount of fear-mongering around it. Yes, we will be exposed to radiation and it will probably increase our risk of heart attack… which is fine, because we’re not coming back and I’d be having a heart attack ON MARS. Which is way more awesome than having a heart attack in an Earth-bound nursing home. NO – it will not make us stupidNO – it does not make a Mars mission impossible. Mars One has written up a great article on what the actual radiation risks are and how they can be mitigated, but I’ll be writing a far more in-depth article on why radiation is NOT the biggest hurdle to sending people to Mars.

Because realistically the biggest hurdle to getting people on Mars has always been…

Entry, Descent & Landing (EDL)

A fractionally elevated risk of cancer and/or heart-attack is nothing in-comparison to the risk of hitting the top of the Martian atmosphere at 9km/sec without bouncing off into deep space, using your spacecraft as a brakepad as it heats up to glow white-hot while ripping through the atmosphere, firing a rocket engine into the hypersonic winds to try and slow down, and then using those rockets and their highly limited fuel to land without becoming an impact crater.

The challenges of Entry, Descent and Landing (EDL) is why the heaviest thing anyone has successfully landed on Mars to date is Curiosity Rover at around 900kg. If NASA wants to send astronauts to Mars and bring them back, they need to be able to land a Mars Return Vehicle that will weigh roughly 30,000 to 40,000 kg. For comparison though Mars One’s Environmental Control and Life Support System is the single heaviest component that needs to reach the surface of Mars safely at 7,434 kg, while SpaceX is talking about being able to deliver 13,600 kg to Mars with Falcon Heavy.

Above all else not being able to land heavy stuff on the surface has been the biggest engineering hurdle faced in the race to Mars, but it looks like the folks at SpaceX are up for the challenge.

So there you have it! I’ve been looking forward to hooking into some serious space engineering and psychology posts to off-set the more personal posts I’ve been working on lately, and I’m really interested to seeing what I can feed from these new posts back into “Becoming Martian” as I continue to edit it.

Onward and upward!


Space – Choosing a Crew for Mars

With Mars One’s next astronaut selection round later this year looking to bring the current crop of 100 candidates down to 18-36 who will then start full-time training, I figured it was time to talk a little about how the next round will progress and what the selectors have said they want from the first Martian colonists.

When most folks talk about finding the “best” people for a job, especially when it’s space-related, there’s unfortunately one default reference pretty much every one leaps to:

It’s hardly a popular opinion, but the truth is today the “The Right Stuff” is a fantastic catalog of what NOT to look for when selecting astronauts for a mission to Mars. The Mercury program (and consequently “The Right Stuff”) was all about flying solo: selecting the best trained and most technically proficient pilots the US military had – who were the right size – and launching them alone on the US’s first foray into space. They had to meet incredibly stringent requirements: only test pilots under 40, no taller than 180cm (5’11”), no heavier than 82 kg (180lb), with a bachelor’s degree or equivalent (uncommon in 1959), and with over 1,500 hours flying time to meet even the basic requirements to apply at all. And don’t think the Russians were doing things differently back then: a huge factor in Yuri Gagarin being the first human in space was at 158cm (5’2″) and 70kg (153lb) it was easier to fit him inside Vostok 1. 

Good-sized hands though. The best hands. Very beautiful hands. Slightly large, actually.

I don’t say any of this to take away anything from any of the early astronauts – all of them were incredible people who dedicated and risked their lives to be the first to venture beyond Earth’s atmosphere. But it’s important to recognise the criteria the early astronauts were selected on is radically different from what future Mars mission astronauts/colonists will be selected on. From the first Russian space stations, to the US shuttle program, through to the astronauts selected for 6 and 12 month missions to the International Space Station, we’ve seen significant changes in the way selectors assess potential astronauts, and by far the biggest changes have been how candidates are psychologically screened and prepared.

The critical difference between the first people in space and now? You’re still hurtling through the darkness in a hazardous tin can; except now it’s a fraction larger, you’re going for a lot longer AND you’re going with other people… so just because you’re a really great pilot doesn’t mean you can get away with being a jerk anymore!

Sorry Steve – you’re staying home

There is still a requirement to be fit and healthy – I needed to pass the equivalent of a commercial pilot’s medical exam for example. But because we’re spending longer in space and not jamming people into tiny cockpits for the entire trip, being short and light isn’t such a necessity anymore (it still helps though). You also obviously still need to be smart enough to process all you’ll need to learn, which is why Mars One tested our technical knowledge during the interview phase. But given Mars One is planning on sending people to Mars for the rest of their lives, finding people who have a clear sense of purpose and get along with others under isolation and stress is way more important than finding people who are really, really good (and short) pilots.

Basically we need to find people who at the bare minimum can live together without someone turning into Jack Torrance after a few months.

Wendy! I’m home to the hab!

Given Mars One isn’t planning to launch a crew until 2031, they also have 12-13 years to train candidates – more than enough time to learn anything and everything they’ll need provided they have the right motivation and a proven capacity to learn.

So with a greater focus on 1) Why someone wants to live to Mars, 2) How they get along with others & respond to stressful situations while isolated, and 3) their ability to learn new things quickly; Mars One’s selectors identified five key characteristics they sought in an astronaut candidate: Resiliency, Adaptability, Curiosity, Ability to trust, and Creativity/Resourcefulness. The short answer? Mars One is essentially looking to send 4 MacGyvers to Mars who are also great housemates.

No, not the “new” series. I mean the one that was actually good.

I’ve always been a fan of the MacGyver approach: he knows what he’s trying to achieve, he knows what resources he has available, he knows how much time he has, and he doesn’t ask permission to use something in a unique or different way to solve a problem. In short, he survives because he’s a “do-er”. Even so, MacGyver was a bit of solo act: saving the day through knowledge, lateral thinking and cool under pressure… but usually on his own, and everything usually cut to fit a 48 minute episode. To find a much closer parallel to the psychological endurance required by the Mars One crew, we really need to look back more than 100 years to a group of explorers trying to cross the southern pole of this planet.

The 28 crew members of the “Endurance”

The story of Ernest Shackleton’s “Imperial Trans-Antarctic Expedition” (commonly referred to as the “Endurance Expedition”) is far better told by others elsewhere – “Endurance” by Alfred Lansing is brilliant, but even the Wikipedia entry is a great way to get an idea of what it was like: 28 men surviving back-to-back winters on the Antarctic ice after their ship was crushed in pack ice, before attempting one of the most daring rescue missions in history by paddling 1300km in open boats across the Southern Atlantic then hiking for 3 days across the unexplored interior of South Georgia to reach help.

Many look to Shackleton as one of the greatest leaders of all time, and rightly so. I’m currently rereading “Shackleton’s Way” by Margot Morrell, which focuses on the incredible leadership lessons that can be taken from Shackleton and the Endurance expedition. The entire book has countless pearls of wisdom that can be easily applied to the planning and execution of a human Mars mission, but arguably the most important is how Shackleton selected and prepared his crew. And even if you haven’t heard of Ernest Shackleton before, there’s a good chance you’ve heard of this though: 

“Men wanted for hazardous journey, small wages, bitter cold, long months of complete darkness, constant danger, safe return doubtful, honor and recognition in case of success. Ernest Shackleton 4 Burlington st.”

There’s been a persistent myth that Shackleton took out this advert to recruit for the Endurance expedition, but unfortunately it’s almost certainly #FakeNews. The reality is Shackleton didn’t need to put out an advert: he received more than 5,000 applications when the expedition was announced, which is surprisingly similar to the 4,227 people who submitted completed applications to Mars One (Note: 202,586 people registered & confirmed their online applications, but the process to actually complete the application was… thorough).

Shackleton had the applications sorted into 3 boxes: “Mad”, “Hopeless”, and “Possible”. You could argue everyone applying was “Mad”, but Shackleton was looking for people who knew what they were getting themselves in for, had the experience he needed, and most importantly shared his vision and enthusiasm for exploration. After discarding the “Mad” and “Hopeless” boxes, the “Possible” applicants were then put through some pretty unconventional interviews, like asking the expedition physicist if he could sing. Shackleton wasn’t looking for the “best of the best” – he was looking for people who were qualified for the work and could live together peacefully for long periods without any outside communication. In the wise words of the man himself “Science or seamanship weigh little against the kind of chaps they were”. As Mars One selectors Dr Norbert Kraft and Dr Raye Kass point out in their Huffington Post article on Mars One crew selection, Shackleton chose people who were optimistic and could keep morale up like musicians and storytellers.

Meterologist Leonard Hussey, and his banjo that Shackleton considered “vital mental medicine”

Above all Shackleton picked people who did their job really well, but weren’t prone to being miserable or obnoxious when things got tough. People who great at what they did, but focused on building a sense of camaraderie among the group and were always quick with a laugh especially when things have gone wrong. Rather fittingly, Ernest Shackleton went to Antarctica with people very much like Mark Watney…

As we head into the next selection phase of Mars One narrows the group down to the 18 to 36 who will start training, and as that training continues towards a launch date, more and more questions will be asked about the psychological challenges the crew will face, and ultimately what makes the ideal crew for a one-way mission to Mars. My suspicion is they will be the same kind of people who were aboard the Endurance in 1914 as it approached the pack ice: people who love what they do and working with the people alongside them, who know deep down why what they’re doing is important to them, and who love laughing at every ridiculous aspect of the bizarre adventure they signed up for together.


Space – The Good, the Bad and the Ugly [Mars One Update]

There’s been a mountain of recent updates on Mars One over the last few months, so I figured it’d be a a great opportunity to kick off the regular “Space” posts with a full-spectrum round-up of the good, bad and ugly of all that’s happened.

The Good

After a huge amount of initial support and media coverage Mars One has had a really hard time transitioning from a small space startup with an incredible idea into a functioning space company with revenue stable enough to take that incredible idea further. After limping along with a small team trying to make ends meet while encouraging top-end investors to finance a significant proportion of the whole project, the merchandise store and private investment have generated a steady baseline stream of income over the last 3 years and provided the financial evidence of the business plan smaller investors needed.

By splitting Mars One into the not-for-profit “Mars One Foundation” (which will carry out the mission to Mars itself)  and the for-profit “Mars One Ventures”, it’s now far easier for investors to both see the income being generated and to make the decision to invest to as long as they like, regardless of their personal interest or support for a mission to Mars. By making Mars One Ventures more attractive to investors who may not care if the mission succeeds or not (but want a clear and immediate return on investment) and sharing a percentage of the profits made with the not-for-profit Mars One Foundation, they’ve significantly improved the chances of us successfully colonising Mars!

Those chances have only been improved further by an €87 million takeover deal with Innovative Finance AG (aka InFin), where the two companies merged and InFin’s board and shareholders voted to renamed the company as “Mars One Ventures AG” to become Mars One’s for-profit arm. The biggest benefit of the InFin deal is that Mars One is now listed on the Frankfurt Stock Exchange, significantly improving opportunities for international investment as they try to raise €10 million for initial funding. And it’s immediately started to pay off: Mars One just secured a €6 million investment from World Stock & Bond Trade Limited based in Hong Kong!

At the same time Mars One’s continued to research and further develop the technologies that we’ll need to live permanently on Mars. After a massive hold-up waiting for confirmation of ITAR compliance, the design study into Mars One’s surface suits from Paragon Space Development Corporation was finally released! The “Mars One Surface Exploration Suit (SES) Conceptual Design Assessment” is precisely what Mars One needed, but a 40 page of engineering design study isn’t exactly everyone’s cup of tea. Luckily Oscar, Ryan and I were given access to the report before it was published publicly so we could put together an easy-to-read abstract with all the important details.

Among all of this we’ve also seen some really promising research on growing food in Martian soil from a team at Wageningen University, as well as Elon Musk’s huge announcement about the Interplanetary Transport System at the 2016 International Astronautical Congress in Guadalajara – which I could watch in person thanks to everyone’s amazing generosity!

So all in all a pretty incredible year for Mars One and space exploration generally, right?

The Bad

To make that transition from a space startup into a functioning space business – securing the InFin deal, the stock exchange listing, the €6 million investment, ect – Mars One had to really look at both their finances and the existing business model, and at what would make them more attractive to mid-level investors (rather than just overly generous billionaires). One of the biggest concerns potential investors had was how aggressive & unforgiving the timeline was to get the first launched to Mars by 2026 – just 10 years to launch a demonstration mission, 2 rovers, 2 surface habitats & 6 additional landing capsules, a transit habitat, and train 24 people to live the rest of their lives on Mars.

All of the candidates got news of the delay confidentially months before, but at the start of December Mars One publicly announced that we’ve delayed the timeline by 5 years with the first crew now launching in 2031. Back in 2012 when Mars One had first said they’d put people on Mars by 2021 I thought it was ludicrous, but also knew that while it probably wasn’t reasonable there was no reason why it wasn’t possible, and wanting to live on Mars is a ludicrous goal in the first place. So I was relieved when the first crew’s launch date was pushed back to 2026 – it meant Mars One was flexible while still making real & measurable progress as time went on.

I’m a physicist and engineer so I can see the technical challenges Mars One will face but also possible solutions – what I couldn’t clearly understand was how we’d pay for it. Being so early in the technology development phase I knew mean’t times and costs would change, but besides the TV revenue and technology licensing it wasn’t exactly really clear to me how we could raise the money to continue with selection, move on to training, or pay the contractors to develop the engineering solutions we needed. So while the delay is technically BAD news, I was genuinely overjoyed when I got news that the first crew launch had been pushed back again to 2031 because the news came bundled with Mars One’s revised business plan. It was the first time that the finance side of things truly made sense to me – the first time I could see a clear and reliably laid-out path forward.

The other “bad” news is that we are definitely not alone in the race to Mars – the Interplanetary Transport System Elon Musk presented at the 2016 IAC laid out a very clear and detailed plan for putting humans on Mars (optimistically) by 2024… even if Elon is giving them all a return ticket. There’s little doubt SpaceX is better financed than Mars One, that they are well and truly already in the rocket-building business, that Musk has a proven track-record of doing “the impossible” and he has repeatedly stated that SpaceX was started for the purpose of making humanity a dual-planet species.

Personally I’ve never cared about being first – like Musk my desire is to make our species a dual-planet one, and the best way I can support that is by putting my hand up to go. So SpaceX’s goal of the first humans on Mars by 2024 doesn’t bother me because I just want SOMEONE to go – I can follow later if the opportunity is there. What’s really interesting to me about SpaceX and the ITS announcement though is that Musk has also said that they would not be training crews internally.

What a heap of folks don’t realise is that SpaceX want to build the trains and the tracks (the rocket that will take people to Mars) as well as the train stations (the Methalox refueling depots on Mars or beyond). But what they’re not going to be doing is training people up to be the conductors (the crew) – that would all be handled by a commercial crew provider… maybe say an organisation that’s planning to select and start training people in 2017 to live permanently on Mars?

The (very) Ugly

Which brings me to the last bit of news I find myself sharing a lot lately: YES! I’m still in the running and still talking about Mars One all the time! After spending most of 2016 overseas touring Cosmic Nomad, I’ve returned to Australia to find no shortage of people asking if I’m “still going to Mars”. And since the US Presidential election a LOT more asking if they can come with me…

With Mars One securing the €6 million investment, I’m really excited to say that the next selection phase is going ahead in 2017! We’re not sure exactly when in 2017 (my suspicions are September), but the next phase will start with the 100 remaining candidates getting together in one place forgroup testing. After a brutal 5 days of assessment to reduce the group down to around 40, the remaining candidates will work together in teams to face isolation challenges, followed by an individually grueling “Mars Settler Suitability Interview”. After the interviews just 18 to 36 of us will be offered full-time contracts Mars One, starting over a decade of training to prepare for life on Mars.

And for those of you who didn’t apply back in 2013 but also want to start a new life on a different planet to Donald Drumpf, there is hope for you too: Mars One will be reopening for applications in early 2017!

It’s been a weird a wonderful ride so far, and whatever happens is sure to be life changing – I can’t wait to see what adventures Mars One brings in 2017!