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Rescuing Jeb
Dec. 10th, 2013 08:53 pmIn my last Kerbal post, I had gotten Jeb (and his assistants, Bill and Bob) to Duna. They landed, they walked around some, they took off again. Then they were out of fuel and hung out in orbit for a couple weeks.
Tonight, I rescued them!
The first attempt was to just get them some fuel. I built a little robotic probe with a big fuel tank and flew it over there. Unfortunately, it took most of the fuel in it to get it there... I'm not good at interplanetary flight yet. So that was a bust. That was about a week ago.
Tonight I tried again though. I built a probe with a larger tank and a nuclear engine. I was able to get it into orbit really easily (I discovered a foolproof way to build launch vehicles), and then flew it over to Duna. I'm getting better, slowly, at interplanetary transfers. The hard part isn't getting to the planet, it's getting to a decent orbit once you're there. You have to spend a huge amount of delta v to get into orbit at all, and unless you make correction burns way before the encounter your orbit is going to be crazy tilted and really high. Like, the first Jeb mission ended up in a polar orbit around Duna.
So, okay, got there. Rendezvoused and docked with the stranded ship. Now for the second part of my plan: the ship that I first sent there had four small landing rockets on it. These are great for landings but they use way too much fuel for interplanetary flight. The nuclear engines are the exact opposite: low thrust but extremely low fuel usage. The same tank that had maybe 2000 m/s delta v gave me over 5000 with a nuclear engine.
Which meant that after I got to Duna, normalized my orbit, rendezvoused, and docked, it made sense to just throw away most of the original ship and carry the crew capsule home with the probe. Which I had about twice the delta v I needed to do. I burned back home, made a correction burn (getting decent at those by now), and got back into Kerbin orbit. I could have made a really fast reentry there, but I figured what the hell, and actually took a couple orbits to slow myself down. I managed to actually stay out of the red zone on the G meter during reentry.
Next task: rescue the guys I left stuck on Duna's moon. That'll be tough because they can't even take off, they're so out of fuel.
Tonight, I rescued them!
The first attempt was to just get them some fuel. I built a little robotic probe with a big fuel tank and flew it over there. Unfortunately, it took most of the fuel in it to get it there... I'm not good at interplanetary flight yet. So that was a bust. That was about a week ago.
Tonight I tried again though. I built a probe with a larger tank and a nuclear engine. I was able to get it into orbit really easily (I discovered a foolproof way to build launch vehicles), and then flew it over to Duna. I'm getting better, slowly, at interplanetary transfers. The hard part isn't getting to the planet, it's getting to a decent orbit once you're there. You have to spend a huge amount of delta v to get into orbit at all, and unless you make correction burns way before the encounter your orbit is going to be crazy tilted and really high. Like, the first Jeb mission ended up in a polar orbit around Duna.
So, okay, got there. Rendezvoused and docked with the stranded ship. Now for the second part of my plan: the ship that I first sent there had four small landing rockets on it. These are great for landings but they use way too much fuel for interplanetary flight. The nuclear engines are the exact opposite: low thrust but extremely low fuel usage. The same tank that had maybe 2000 m/s delta v gave me over 5000 with a nuclear engine.
Which meant that after I got to Duna, normalized my orbit, rendezvoused, and docked, it made sense to just throw away most of the original ship and carry the crew capsule home with the probe. Which I had about twice the delta v I needed to do. I burned back home, made a correction burn (getting decent at those by now), and got back into Kerbin orbit. I could have made a really fast reentry there, but I figured what the hell, and actually took a couple orbits to slow myself down. I managed to actually stay out of the red zone on the G meter during reentry.
Next task: rescue the guys I left stuck on Duna's moon. That'll be tough because they can't even take off, they're so out of fuel.
