Mission: Jool, Maybe

While writing yesterday’s post, I encouraged myself to try to get that ship to Jool. In one sense, it was successful. In another sense, it was worse that I imagined it could be.

When the launch window opened, MechJeb launched DiamondDog I on a trajectory toward Jool. It didn’t give me an encounter with the gas giant, but that’s nothing unusual. I kept trying various maneuver nodes, at various spots along the route, but nothing could get an encounter. It seemed that MechJeb had missed the planet completely.

Finally, just before I was going to give up and try again with another launch, I tried using MechJeb’s rendezvous options. It gave me an encounter with Jool! The thing was, the maneuver node was way back at the far side of Kerbin, and the new trajectory went beyond the orbit of Jool before arcing back to the encounter.

In other words, DiamondDog I was on an orbit away from Kerbin,and toward Jool’s orbit. It would have to continue its path all the way to where Jool should be, return back to Kerbin, fire a short maneuver, go back to Jool’s orbit a second time, pass Jool’s orbit, and encounter Jool on the return toward Kerbin.

I decided, what the heck, I’d try it.

It took a very long time, even at the game’s maximum time acceleration. It terms of in-game time, the encounter with Jool came 18 years after DiamondDog I had left the launch pad. But for the first time ever, I had an encounter with Jool.

I became aware of how enormous Jool is, and what an enormous sphere of influence it has. When the ship reached a point where the it had to start a circulation burn, it was out beyond the obit of the farthest moon. Giant Jool was a speck out in space. That circulation burn lasted 32 minutes – in real time. DiamondDog I, at that point, was powered by a single atomic motor (very efficient, but  with low thrust) and a whole lot of fuel.

I got an orbit around Jool, and kept reducing it, kilometer by kilometer, with maneuver burns of 5 to 15 minutes each. I was on the computer for hours last night.

Here’s something Kerbal Space Program taught me about orbital mechanics: maneuvers done on one side of an orbit change the opposite side of an orbit. So to reduce a circular orbit to a smaller, circular orbit requires two maneuver burns – one on each side.

Last night, I established an orbit just beyond Laythe – the innermost moon. I realized that I was spending a lot of time just trying to fix a bad space flight. I saved the game and shut it down. I was getting tired and discouraged.

I’m going to take some time to think about what to do next. I may run out of fuel before I’m able to get close enough to Jool to launch the orbiter. It would be a shame to have spent all this time just to abandon the mission, but maybe that’s best. Do it right instead of continuing to fix it. Or, maybe I should forge on ahead, get as far as can, and pick up some knowledge along the way.

Another possibility, which I just now thought of: I could try to establish an orbit around Laythe, ditch the Jool orbiter for now, and go ahead with a Laythe landing.

I’ll play some The Sims 4 and think about it.


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