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 MENTIONING 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!
Radiation
*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 stupid. NO – 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.
Link to SpaceX CRS-8 First-Stage Landing video
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!
