Kerbal Space Program: Interplanetary Voyage, Take Two

Much of the time I’ve spent playing Kerbal Space Program since my last post on the subject has been focussed on collecting as much science as possible by landing on different areas of the Mun and Minmus, using my space stations. As a result, I’ve been able to unlock the majority of the game’s available parts via the tech tree. I’ve also been trying to figure out how to complete the more ambitious contracts that I signed up for, such as building a Mun base, or extracting a large amount of ore from the Mun and returning it to Kerbin. I haven’t progressed too far with these: not only are Mun base components going to be big and heavy, but they ideally need to be attached to each other on the surface rather than in orbit. I currently have an unwieldy laboratory with wheels attached orbiting the Mun, with a lone Kerbal scientist onboard and only a sliver of fuel in its tank; and aside from determining a landing site based on scanning for maximum ore concentrations from orbit, that’s as far as I’ve got with preparing a Mun base so far.

I decided to pursue some other contracts involving asteroids, which I at least had a little experience of. One was to place a Class A asteroid (the smallest variety) into orbit around Kerbin; the other was to place a Class B asteroid into orbit around the Mun. As I happened to discover a Class B asteroid first, that was what I began with, launching the same spacecraft I had used previously with Jebediah Kerman aboard.

Catching asteroids is considerably harder than performing a rendezvous with something in a stable orbit. The asteroid almost certainly won’t be coming in anywhere close to an equatorial path, so you have to launch at a wonky angle. Also, you only get one shot at encountering the asteroid before it flies by Kerbin and heads back out into space. And it’s going to be moving very fast as well, so you need enough fuel to decrease the relative speed for a rendezvous to be possible. It was this part that almost scuppered my Class B capture mission: I stumbled clumsily through various manouvers to get my spacecraft as close to the asteroid as possible, using up lots of fuel in the process. Finally, the spacecraft became attached to the asteroid with its giant claw – but what about the second part of the contract, putting the asteroid into orbit around the Mun? I had an idea as to how I could manage it: lowering the orbital plane until it intersected with the Mun’s, time-warping until the spacecraft and the Mun happened to encounter each other, then firing up the engine and placing the spacecraft and asteroid in orbit – job done!

Except I soon realised that while I had enough fuel to adjust the orbital plane if I did it far enough away from Kerbin (lower orbital speed = less fuel required to adjust the plane), I did not have enough to slow down into Munar orbit. There was only one thing for it: launching an unmanned refueller with its own giant claw. With a rendezvous which was far more efficient than the one I’d needed to catch the asteroid, it attached itself to Jebediah’s craft; since this counts as a docking in-game, it could transfer most of its fuel, before releasing and being sent on a suicide dive into Kerbin’s atmosphere. Jebediah, meanwhile, could now place his asteroid in Munar orbit and finally go home.

When a Class A asteroid finally appeared in the vicinity of Kerbin – they appear to be rare – Jebediah was soon heading into orbit again. At least all that was needed here was to put it into orbit around Kerbin – but what about the task of catching it? After some experimentation through quicksaving, I managed to crack the secret: with some good timing and positions of manouvers, if I could get the spacecraft’s path to match that of the asteroid as closely as possible while getting an encounter at the point of closest approach, the relative speed was only a few hundred metres per second. As a result, Jebediah could rendezvous with the asteroid using far less fuel than on previous missions. And with the asteroid being so small, it was a simple matter to slow down and place it in orbit without its mass sending the spacecraft into a vomit-inducing spin.

With those two contracts out of the way, I started thinking about a second voyage to another planet: Eve, the in-game equivalent of Venus. After some deliberation about whether or not to try a manned mission, I decided to send a probe this first time round. I used the same basic template as my Duna probe, Watney 1, with some modifications based on the difficulties that the former probe had encountered. Watney 1 had had just enough fuel to land; the Eve probe would launch with extra engines and fuel tanks. When Watney 1 aerobraked in Duna’s atmosphere to save fuel, it lost its unretractable primary solar panels and had to rely on the smaller, static backups; I gave the Eve probe retractable solar panels, and a heat shield at the front for aerobraking. Watney 1 had not had enough electrical power to run all its experiments; I gave the Eve probe extra batteries. And finally, I scrapped the rover which had failed to work on Watney 1, and used the service bay for the science experiments instead.


Things got off to a good start: my probe, named Zeta 1, was still fat on fuel when it was sent on its way to Eve. Upon arrival at the purple planet, it didn’t lose quite as much speed as I’d hoped with aerobraking in the atmosphere, and had to use a lot of its remaining fuel going into orbit. But it got where it needed to be, and was soon transmitting science, even pulling off a close encounter with Eve’s moon, Gilly. Once I had done all I could in orbit, it was time to try landing. But this was where things went pear-shaped.

At some point when re-working the existing template for Watney 1, an attachment between two parts of the rocket must have shifted so that they were no longer physically joined; the game compensated for this by creating struts to hold them together, without me noticing. The result was that when I commanded the landing segment of Zeta 1 to detach from its booster, the magic struts continued to hold the two segments together. This meant that the landing heat shield was not being presented to the atmosphere, and that the craft was unstable as it descended. I could only watch helplessly as my lovely probe spiralled out of control, most of its parts exploding one by one from the heat of re-entry. Amazingly, when the flames died away, there were still some bits left: the service bay containing the scientific instruments, the parachutes, and the magic struts that had caused all the trouble. The parachutes still deployed, and slowed by Eve’s thick atmosphere, what remained of Zeta 1 drifted gently to the service. The instruments were even still working. But with the antenna having been destroyed, there was no way to transmit the data back to Kerbin and profit from the science collected.

Still, with all the data gathered from orbit, and the rewards given for achieving Eve-related milestones, the mission had been at least a partial success. And as with the first mission to Duna, it provided new experiences to learn from, for next time.


About velociraptor256

Hi, my name's Richard. I created this blog to talk about my interests - and I have quite a few of those. I love zoology in general, herpetology in particular (especially snakes!), writing (have won National Novel Writing Month seven times so far, plus three Camp Nanowrimos), reading, astronomy, palaeontology, and travel. Thank you for coming to my blog, and I hope you find something that interests you here!
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