[KSP] Battle Report!

+ Show Spoiler [Boring Metablog] +

So I haven't done a blog in a while. That's because I basically do three kinds of blogs:

1) Blogs about games I like, describing the game, giving my thoughts, and recommending that you check it out, too.
2) Playing to Win! blogs, talking about a game that isn't usually viewed in a competitive light and trying to analyze the strategy in some detail.
3) Starcraft-related blogs of various kinds.

The first type only comes when I have a new game that I'm excited about. For instance, I did one about Kerbal Space Program way back when I discovered it. I did one about Pokemon Puzzle League, because it's one of my favorite games. Most recently I did one about Divekick! But discovering a new game I love happens relatively rarely, and so these blogs are accordingly rare.

The second type is a lot of fun to write, but PtW blogs take a ton of work, since obviously to tell you how to play to win at something, I have to myself be good enough at the game to know how to play to win. I still want to do another one of these about Puzzle League at some point, but in the mean time, it's tough to come up with a sufficiently casual game and analyze it to death.

The third type happens when I have something to say about Starcraft, which is rare recently since I've been too busy with school to keep a regular practice schedule.

But I like blogging about video games, so I decided to come up with a new kind of blog to write. I'm trying this one out:

KSP Battle Report!

In homage to TL's rich tradition of battle reports, I thought I'd do a battle report (or series of battle reports) about one of my favorite games, Kerbal Space Program. Since KSP has no replay system this creates some interesting challenges with documenting my missions as they happen. And of course, you may argue that battle reports of a single-player space exploration are not interesting to read in the same way Starcraft battle reports are. But space travel has always been fraught with dangers: vacuums and low pressure environments, freezing temperatures, having to screenshot the game while you play it, and people being uninterested in your space adventures are just a few. A true pioneer must press forward despite the danger!

So first, a bit about the KSP system. Kerbin is the third planet from what appears to be a smallish yellow star called Kerbol. Kerbin has two moons, a large one called Mun and a small, distant one called Minmus. The planets in the Kerbol system are, in order from closest to furthest from Kerbol: Moho, Eve, Kerbin, Duna, Dres, Jool, and Eeloo.

My Evil Kerman Dad Despises Juicy Eggplant.

The Kerbal Space Program's current long-term goal is to send a manned mission to Eeloo and return it safely. This mission will not be easy, and proper development and testing must go into every component of this final mission, so a number of smaller missions will be undertaken to test the ship components which will be used in the Eeloo transfer, landing, and return.

The first component to test is the crew capsule, pictured here:

Driver's seat of interplanetary exploration.

+ Show Spoiler [Part Breakdown] +

1 lander can
2 1.5m RCS tanks
8 RCS thruster blocks
2 1.5m docking ports
8 radial Z-400 batteries
2 radial parachutes
1 solar panel
1 Gravioli gravity detector
1 antenna
1 thermometer

27 parts
Launch mass: 2.41 tons
Dry mass: 1.61 tons
Isp: 260s
calculated delta v: 1030 m/s

This baby's small, but she's well-equipped: seating for a single occupant, docking ports to connect to other craft, RCS to perform orbital operations with ease, 8 radial batteries with a solar cell to ensure constant power supply, 2 radial parachutes to give a reasonable chance of surviving re-entry, and science equipment to conduct experiments and convince the government this mission is worth funding.

The design is symmetrical above and below the lander can. The idea behind this is that if the design is perfectly symmetrical, with the reaction control thrusters placed equally on either side of the center of mass, then it should be relatively easy to use RCS for translation maneuvers without it also inducing rotation. This is so the crew capsule can perform docking and undocking maneuvers in orbit with relative ease.

The crew capsule's test mission is to send Jebediah to the more distant moon, Minmus, and back. So I tossed together a rocket underneath the thing to put it into space:

5, 4, 3, 2, 1... You're in for a ride, Jebediah.

Other than a bit of dizziness on Jebediah's part, the launch to orbit was uneventful. Those orange tanks were just for the trip up, and were dropped soon enough that they'd de-orbit on their own. The final engine stage quickly fired to attain a stable orbit:

Is that Africa we're flying over? Or maybe Italy? Kerbin geography was never my strong point in school.

Now here's the thing about Minmus: It's really high up. Sitting in an orbit of 100 km up, the planet is pretty visible, and the closer, larger moon sitting at 11,400 km is pretty visible too. But Minmus is all but invisible without a telescope at 47,000 km up, there's really have no option but to go to the flight computer and plot different courses until the computer indicates a Minmus encounter. Soon enough, the computer says one has been found:

Jebediah goes ahead and follows the flight computer's instructions, and soon enough he finds himself in the deep of space, taking its word that he's anywhere near where he wants to be in space. At this point even Kerbin is so far away he can barely find it in the sky without the flight computer's help.

See that little black circle on the left side of the sun? That's Kerbin.

Eventually Minmus arrives on the horizon, looking awfully forsaken compared to Jebediah's green home world. Jebediah passes low over the surface of the strange body, doing a quick flyover to survey the terrain.

Minmus is a small ice moon, with such low gravity that an orbit less than 10,000 m above the surface still only requires a tangent velocity of under 200 m/s. Jebediah sets up such an orbit and begins looking for a good spot to land:

The plan for this mission was to leave the engine and large fuel tank in orbit, while the crew transfer module went down for a landing. The orbital period at this height is approximately 42 minutes, so Jebediah has a little over 42 minutes from undocking to land the capsule, plant a flag, collect samples and explore Minmus, and return to orbit to re-dock with the engine and return home. This is where the crew capsule is truly put to the test; if it can undock, de-orbit, land, launch to orbit again, and re-dock with the transfer vessel, it should be able to handle whatever orbital operations will be required of it in a hypothetical mission to Eeloo.

The landing goes approximately according to plan:

Well, we didn't really mean to be leaning like that...

Now Jebediah grabs a flag and gets out to commemorate the historic landing site. He collects a surface sample for the research team to salivate over back at home, and poses for a quick picture.

Damnit, Jebediah! you got the flag backwards, you idiot!

Jebediah landed on Minmus highlands, but in his flyover he saw many large, flat ice fields, including one fairly near to his landing site. With plenty of time left in the 42-minute window, he decides to use his suit's jetpack and EVA down to the ice field ~~for fun~~ for very important scientific reasons. He records his observations for the research team in order to advance scientific progress.

Boy, would this have been a better place to land...

Jebediah radios home to Kerbal Space Center to tell them what a grand time he is having. KSC informs him that his jet pack does, in fact, have limited fuel. Worried he might have to actually walk back, Jebediah begins the trip home. He barely has enough fuel to slow himself down on arrival.

Jebediah quickly gets into the crew capsule and checks the flight computer to see when his ride home will be passing overhead. The flight computer shows him all vehicles in orbit around Minmus:

Nope, nothing to see here.

Panicked, he radios home once again, this time asking in desperation whether the flight computer might be malfunctioning. Kerbal Command puzzles over this dilemma, wondering whether the engine might have de-orbited while Jebediah was messing around. Eventually KSC's tracking center does pick up an object orbiting Minmus at an altitude of 6000 m, incorrectly labelled by the computer as debris. They radio Jebediah, informing him that his ride is, in fact, still arriving at the end of 42 minutes, but that his flight computer has tagged it as debris and will not display it on screen.

Jebediah waits and watches the horizon anxiously for his ride home, desperate not to miss it. Finally it appears in the distance:

[i]Thank God! 47,000 km is a long way to walk home.

He fires up the RCS thrusters and begins to re-orbit, keeping an eye on that object on the horizon. Eventually he manages to get close enough to see it without magnification.

Docking is a finicky thing. One must approach the other craft very slowly on the docking axis, while ensuring that the craft is oriented properly and is not drifting away in either of the remaining axes. To make matters worse, both craft were beginning to reach the night side of the moon, making matters even more difficult. But eventually Jebediah manages to approach close enough for the magnetic attachment mechanism to engage.

Now Jebediah has enough thrust and fuel to escape Minmus orbit, oppose his orbital velocity, and begin falling back to Kerbin. As long as he's returning to Kerbin, he decides to aim for the South Pole, much to the chagrin of the KSC retrieval team charged with reaching his landing site and returning with Jebediah and his vehicle.

The final landing is fairly uneventful. With such a small capsule and two parachutes, the velocity he picked up on his fall back to Kerbin is easily sloughed off to aerodynamic forces. Touching down safely, the mission is a success!

Post-mission Analysis

The crew capsule was easily capable of docking and undocking, making small orbital changes, and even landing in a low-gravity environment. But because Eeloo has a much higher surface gravity than Minmus, RCS thrusters will be insufficient for landing and launching from the Eeloo surface. So next time on KSP Battle Report, I'll design a landing vehicle capable of docking to the crew capsule, dropping out of Eeloo orbit, landing, launching again, and carrying the crew capsule back to a return vehicle.

[KSP] Battle Report!

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