Now playing: flying to the Mun in the Kerbal Space Program

Phil Savage


I have been steadily progressing through my Kerbal Space Program to-do list. My last major milestone was landing on the moon (or 'Mun', as the Kerbals call it). A little too enthusiastically, as it turned out. My capsule ran out of fuel during the descent, and sped helplessly towards its surface. On the upside, it got a great area-of-effect radius. I landed all over that moon.

The next step is to reach the Mun without reducing my Kerbals to green paste. It's a logical progression, but one that will be dramatically more complicated – in part because it requires me to start caring about the safety of these oblivious alien astronauts. Previously, there had been little reason to ensure their survival. When one died, another automatically stepped up to the cockpit, fully trained and unconcerned about reasons for the sudden job vacancy.

Thanks to Kerbal Space Program's recent update, you can now freely hire and assign the crew of each mission. That means I can give myself a reason to start looking after these trusting dullards. I've picked the starting crew – Bob, Bill and Jeb – as the hopefuls to take that giant leap for Kerbalkind. Each mission, I'll need to bring one of them along. Assuming I can keep them alive, I'll have as many attempts as I need. If not, my experiment could be over in as few as three launches. One of them will walk on the surface of the Mun. Or everyone will die trying.

First though, a test. My ill-fated lunar landing was in a small, one-man vessel, it's downfall due to its pitiful fuel capacity. To do this successfully, I'll need to move up to the larger three-man tier, and be more crafty about my power consumption. You need a lot of thrust to leave orbit, but shooting a rocket's load all at once is inefficient and messy. I'm attempting a special launch method: placing six rockets around my main tank, then connecting them through symmetrical fuel lines so that each opposing pair is drained and discarded in sequence. The KSP community call this 'asparagus staging'. I'm betting my space program on the efficacy of spring vegetables.

The result is crudely designed, meant only to ensure I can effectively put the theory into practice before moving onto something more robust. In all the intricacies of fuel line attachment, I forget to enact another theory: that unsecured rockets fall over and explode. Kerbal Space Program takes your ship design literally, and that can spell disaster when gravity is added to the equation. My payload and its terrified Kerbals fall mercifully unharmed through the chaos, rolling to a stop on the ground.

Next attempt: same design, this time with launch stabilisers. The ship takes off, then seconds later starts veering to the right. It flips in mid-air, capsule-over-engines, until the force is too much for the rockets and they awkwardly clip through each other and detonate. I silently curse alpha physics. It's at this point I notice the again-terrified faces of my Kerbals – their expressions livestreamed in the bottom corner of the screen. More importantly, I notice their jumpsuits are all orange: a sign that they're the original trio of Bob, Bill and Jeb. I'd hired new white jumpsuited replacements to pad out the crew roster, hoping to only risk one VIP life each flight. But I hadn't reassigned them.

This is problematic. If the capsule crashes, I lose everyone, and I'll have failed having barely cleared 300m. I hammer the spacebar through the ship's staging, blowing out the rocket's remnants and deploying the parachutes. They open, and, of course, clip through each other. It works, despite the bug, and the Kerbals drift safely to the ground. I silently thank alpha physics.

The whole flight lasted less than a minute, and proved nearly fatal to my crew and my mission. On the other hand, the fuel was correctly draining from the tanks in sequence, so the asparagus staging works. On balance, I'll call that a win.

Things I need to do, in order of priority: one, switch out my crew so that I can only kill one of the original three per trip. I do that. Two, redesign my ship so as to cut down on the acrobatics. This is trickier, and requires an almost complete redesign. I bolt one small and two mid-sized fuel tanks underneath the capsule, each separated by an engine and decoupler, then surround the tube with six of the game's biggest boosters. To that I add aerodynamic cones, support struts, cables and parachutes. Finally, I place 'RCS' thrusters: small multidirectional propulsion nodes designed to allow for turning and finetuning. My hope is that they'll help nullify the fact that my ship's centre of lift is still not central. The space vessel Fly Up You Bastard Mk 1 is complete.

I've played KSP enough to know the launch procedure from memory. I need to head straight up to 10,000m, turn into orbit, wait until the apoapsis (the highest point of my trajectory) is projected for 75,000m, cut the thrusters, drift towards the apex, boost to extend the orbit, escape Kerbin's gravity and start the slingshot toward the Mun. It's an elegant, efficient and masterfully cool procedure.

None of those words can be used to describe what actually happens, though. I kick the thrusters into full power for launch, and they instantly begin to overheat. While I'm busy managing my power output, the ship starts to spin. With the rocket too heavy to effectively use the RCS's rotational thrusters, I'm forced to tap tiny directional adjustments to keep it on an orbital trajectory. Stuck playing Dance Dance Revolution with the keyboard, I'm unable to check my course on the orbital map. By the time it's cajoled into stability, I'm on course to rise 160,000m above the surface.

It's wasteful, but not disastrous. I cut the thrusters and, while waiting for the ship to reach its elevated apoapsis, I replot a course for the Mun. I should be able to do a long, controlled burn and extend out the ship's flight path to put it in line for a direct encounter. Instead, less than halfway through the burn, my first-stage central fuel tank runs out. I've still got two tanks left, but both are attached to dramatically less powerful engines. The action takes longer than planned and, by the time it's done, the ship is only narrowly on course. What once was a near-collision is now barely a drive-by.

There's a long ride before we hit that point, which gives me time to plan a retrograde burn that will take us back towards the Mun's orbit. It's going to be tight: the navball's plotter wants 11 seconds of engine fire, but the current fuel tank shows only a sliver of remaining thrust. The planned manoeuvre is so unstable that, during the journey, the projected flight path flickers between two theoretical outcomes.

In the end neither one happens, and what does doesn't make a lot of sense. As predicted, the fuel tank empties moments before the burn is complete. I'm not in full orbit, but I'm close enough that the final half-sized tank should be able to handle the small burst of thrust needed to make the adjustment and still have enough remaining to descend to the Mun's surface. I hit spacebar to detach the spent tank. The entire ship disintegrates. Er, what? I've now lost the final fuel tank, it's engine and the RCS reserve fuel. These were all things that I needed for basic actions like moving. No, seriously, what?

The capsule is heading towards escape velocity, at which point there's no telling where it might go. Jebediah, my onboard commander, will essentially be lost. Not dead, but unreachable, on some erratic and lopsided orbit around Kerbin. I do the only thing I can think of to keep him in play. I eject him into space.

Each astronaut has a jetpack, and Jeb is carrying enough fuel in his to nudge his tiny mass into orbit around the Mun. This doesn't entirely help me. Rescuing him would likely be more difficult than my current mission. But he's not dead, and, more importantly, his gormless grin lets me know that he's happy with the situation.

The impromptu spacewalk has given me an idea. Back at the vehicle assembly hanger I load up the previous rocket, readjust the staging, and replace the vessel's nose cone with a smaller, upside down capsule. I add a fuel tank and engine, both the wrong way up, and attach the relevant RCS modules and landing arms. Essentially, there's a second, tiny rocket bolted on top of the first one. At every stage, fuel capacity has been my downfall (that, and human error). My new plan is to send three astronauts to the moon's orbit, transfer my chosen pioneer to the one-man capsule, detach the two ships, and ride the lighter one – with its unspent fuel tank – down to the surface. All that's required is for me to not make any mistakes.

Mistake one was not anticipating the effect of the increased mass. The new payload makes the ship heavier and therefore less aerodynamically stable. It wobbles dramatically, takes more thrust to get into orbit, and causes me to misjudge the throttle. By the time I'm in orbit around Kerbin, two fuel tanks have been spent.

Mistake two was not fixing the flaw that caused the entire ship to fall apart when decoupling the second-to-last stage. I'd tested the new design with some trial runs in Kerbin's atmosphere, but only diagnosed as far as 'I guess it probably won't happen again'. It happens again.

I evacuate Bill from the useless three-man capsule, and use his jetpack to spacewalk over to the one-man moon lander. He boards, and I attempt to detach the two crafts – at which point I realise that the decoupler I used isn't a decoupler. This is mistake three. The two capsules are instead welded together, the larger one stuck to the smaller like a mutated mushroom head. Even with these problems, I'm able to use the second craft's full tank to reach the Mun's orbit. Which is where mistake four happens.

This final mistake is an extension of the third. The original capsule added too much mass to the ship. As the Mun's gravity takes hold, the tiny engine can't reduce the descent speed. It crashes into the surface, killing Bill and his two subordinate crew members, both of whom were strapped dutifully into the first capsule.

Of my three chosen Kerbals, Bill is dead and Jeb still orbits merrily around the Mun. Bob is my last hope. His ship is a slight modification of Bill's, tweaked in the hope of fixing the maddeningly undiagnosable glitch that was causing its predecessors' staging malfunction.

For once, the launch goes well. This ship is no better designed but, after numerous tests and failures, I've learned to pilot through its eccentricities. My second tank finally runs dry during the transfer to the Mun's orbit. Now to see if my modifications work. They do! The ship doesn't fall apart. It does wobble alarmingly, and I finally realise the problem. The charge of the decoupler was too powerful for the smaller remaining pieces, so it instantly ripped them apart. This time, the even tinier pieces shake and strain but remained attached; held together for reasons known only to God and alpha programming.

Reaching the Mun's orbit, I evacuate Bob from the ship, and pilot him towards the second craft. The two halves detach, and the smaller lander begins its retrograde burn to the surface. It's easier without a giant capsule welded to its roof, and the lander slows to a safe speed, eventually – nervously – reaching the ground. Bob Kerbal becomes the first of his kind to traverse the surface of the Mun (as anything other than a puddle, that is). I haven't got the heart to tell him that he'll be there for a while. I left the parachutes on the other half of the ship.

About the Author
Phil Savage

Phil has been PC gaming since the '90s, when RPGs had dice rolls and open world adventures were weird and French. Now he's the deputy editor of PC Gamer; commissioning features, filling magazine pages, and knowing where the apostrophe goes in '90s. He plays Scout in TF2, and isn't even ashamed.

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