Unexpected Discoveries
Quite some time ago I talked to a good friend who is a teacher about Kerbal Space Program, and how it might make a great activity day at school during their “Space” topic. She agreed, but as with most great ideas, they are easily forgotten.
This evening I started out on the route towards an eventual classroom session – building a succession of rockets that would fit in with some kind of lesson plan. The first rocket would be big enough to re-create Alan Shephard's sub-orbital Mercury flight, the next would be big enough to re-create John Glenn's orbital Mercury flight, and so on.
The third rocket off the production line dwarfed it's predecessors – with an initial stage big enough and powerful enough to essentially lift the orbital rocket into orbit. The master plan? Lunar orbit.
The launch went better than expected. I never do the math – it's more a case of “strap a huge engine and fuel tank on, add a few solid boosters, and see if it gets off the launchpad without exploding”. We throttled up once out of the lower atmosphere, and established a high orbit before doing a short burn to transfer into the Moon's sphere of influence.
Everything went a little too well – resulting in trying to spin the rocket around for Lunar orbit insertion with several tons worth of main rocket engine still strapped to the back – and still half-full of fuel.
After circularising the orbit a thought occurred to me – I could use the fuel to approach the surface as Apollo 10 had done. The rocket wouldn't be able to land, because the final stage had no legs – but it would be able to get close before lifting back to orbit and travelling home.
As we swept around the third orbit into daylight, the remains of the main stage fuel were burned, and a parabolic trajectory aimed for the edge of a major crater on the equator of the moon. Everything went like clockwork – falling through 15,000 metres, spinning the spacecraft around, and lighting the next stage to slow the descent, and halt movement over the ground.
Then, at about 1000 metres above the surface, I saw it. A glint in the distance. At first I thought it might be a graphical artifact – a bug in the game. Then curiosity got the better of me, and I started figuring out how far away it might be, and what on earth it was.
Moments later, instead of punching back out to orbit, the remains of my spacecraft was scudding across the surface of the moon, a few hundred metres up, headed directly for the mystery object in the distance. I had plenty of fuel and given that most of the rocket had been ejected now, the remaining hardware weighed very little – so I was burning very little fuel either.
Closer, closer – it has structure. Ok. It's some kind of cube structure with something on top. Hang on... that's a sculture of a Lunar Lander. On a raised plinth, in the middle of a huge crater field. I slowed the rocket almost to a crawl, and passed by the southern edge of the monument – and could just make out the writing on the shadowed side of the base;
“Neil Armstrong – 1930 – 2012”
I will admit to grinning like somebody had jambed a coat hanger in my mouth. What an amazing thing to hide in the game.
In order to find it again, I realised I had to plant a flag on the ground – but the rocket had no legs! Ok. Immediate silly idea – fire the final stage, leaving me with very little fuel, and land the rocket directly on it's exhaust.
It took a few minutes to find ground level enough to land the rocket without it toppling over, but I did it – and after satisfying myself that it wouldn't topple over, performed the EVA.
After taking photos for posterity of my little Kerbal dude standing proudly alongside the sculpted Eagle lander, we climbed back aboard what was left of our spaceship, and very carefully set out for home – watching the fuel all the way.
After reaching Lunar orbit, and then punching out to escape the Moon's sphere of influence, we began drifting back towards Earth (or “Kerbin”, as it's called in the game). The fuel ran out while trying to burn off speed for a direct return trajectory. After drifting home for a few hours, we would loop around the Earth at a closest approach of about 350 kilometres, still travelling in excess of 4000 metres a second.
Then I had another brainwave. The RCS thrusters. Normally they are only used for maneouvering, but I had packed more fuel than needed. If I switched to docking mode I could fire them all in the same direction for several minutes if needed.
It worked.
We skimmed into the upper atmosphere and burned cherry red across the night sky, leaving a trail of fire behind us before dipping towards the ocean, and opening the parachutes.
Home in one piece. Just. And memories of finding the first Easter egg we had ever found in a video game – and perhaps the coolest.