multitasking experiment

Blaugust 2015 Day 29

I had planned to spend last night’s gaming time in Champions Online, but the patcher was running extremely slowly, so instead I tried Star Trek Online and it timed out on the character loading screen. Cryptic seemed to be having some kind of network issues, although I didn’t try Neverwinter to see. Instead I took it as a sign to go play more Kerbal Space Program.

In Kerbal, I decided I’d messed around with the planning stages of my Jool mission enough. It was time to start launching rockets. I started with the crew module for the explorer ship. I figured that way I could rendezvous with the hydrogen tanker, dock it, and then dock the engine module with out having to do and undocking and rearranging.

   

I took me three tries to get the launch right. I ended up having to go straight up more than I wanted before turning the ship, so I used more fuel getting into orbit than I planned on, but I still have enough fuel remaining to rendezvous. Docking also turned out to be quite challenging. I used more than 60% of my mono-propellant getting into position and closing the remaining distance. A lot of that was due to the mass of the vehicle compared to the reaction wheels and the fact that I didn’t include RCS at the base of the rocket. All of the thruster blocks were on the crew module. I also made the whole process harder by launching when the hydrogen tanker was on the opposite side of Kerbin, so it took quite a few orbits to catch up with it.

The engine module launch when much smoother. The total rocket mass was a bit heavier (387 tons versus 316 for the crew module launcher), but I added extra fuel and engines to the initial stage to compensate and account for a less efficient ascent path. I also saved myself a lot of headaches and waited until the hydrogen tank and crew module were nearly overhead before launching, so I wouldn’t have much work to catch up.

 

 

I only needed one try for this launch. I actually managed a better ascent path as well, although I did still end up in a high orbit than I wanted to. But it didn’t take much fuel to correct that. You can see from the third picture with the fairings off that I sent the engine module up backwards. I wanted to keep the engine and reactor weight at the top of the rocket to help with stability (think of a dart if that’s confusing), and the large docking port that would eventually couple to the crew module was a strong spot to attach to the launcher. Rendezvous was very easy this time since I’d made a better choice on launch time. Docking was also painless, especially compare to the crew module, since the engine module was empty of fuel and only 31 tons where the crew module was fully stocked with supplies and 72 tons during docking.

After completing assembly of the explorer, I transferred hydrogen from the big tank over to the ship. I was able to fully fuel the explorer and still have 66% of the big tank left. The tanker will stay in Kerbin orbit awaiting the ship’s return from Jool where it can refuel for a return voyage or a mission to one of the other planets.

My next play session, I’ll send up the lander vehicle and get it docked to the explorer. It’ll attach to the nose with the hydrogen tanker is currently docked. I’m a little concerned about the thrust-to-weight ratio of the ship once I do that. If it’s too low, I’ll have to make a different transfer vehicle attach to the lander and send it out to Jool ahead of the Kerballed mission. In testing it looked like it would be okay though. There are about 280 Kerbal days remaining before the transfer window, so I have plenty of time to finish assembly and send up the crew.

Blaugust 2015 Day 23

Last night should have been my return to my multitasking experiment, and playing anything other than KSP which is what I’d played on Wednesday. But I had just watched the latest trailer for The Martian again and was in a space mood that Star Trek Online doesn’t really fulfill as it is more science fantasy and hard science.

Instead I headed back into the Vehicle Assembly Building to work on the next stage of my Jool exploration mission. My previous design work had been all about building a craft which would take three Kerbals from Kerbin to Jool and allow for refueling at an automated refinery I’d already place at one of Jool’s moons. But I still needed to build a landing craft to take along. After all it would be a waste for three Kerbalnauts to spend years traveling out to Jool and not get a chance to plant flags on at least one of the moons.

I’m actually planning something more ambitious than that, which is called a Jool 5 expedition. Basically, landing on all five moons with a single mission. Something that was much more challenging before Squad added ISRU (in-situ resource utilization) equipment to the game, so now it’s possible to set up refueling locations.

Even knowing I can refuel though, I needed to design a lander that could handle landing and taking off from all five of Jool’s moons. Some like Bop and Pol are relatively easy. Both are small, low gravity satellites, and have no atmosphere. Vall is bigger but not too difficult. Laythe is more of a challenge. Its gravity is 0.8 that of Kerbin and has an atmosphere like Kerbin does which will help with landing since I can plan to use parachutes not burn a ton of fuel to land. The real challenge of the five will be Tylo. It also has a gravity 0.8 times Kerbin, but it has no atmosphere so the entire landing will require fuel, which means twice as much as will be needed for Laythe.

I had a basic stage for the Tylo descent, but was trying to put together an ascent module that would also work for Laythe and the other moons. This is my first design. To take off from Tylo I need better than 1.0 TWR (thrust to weight ratio) and at least 3070 delta-V. The only problem is I don’t like the look of the big tank sticking out.

I started over and played around with some other ideas. The problem was that using more smaller tanks meant more weight for basically the same amount of fuel, which meant a bigger engine or more engines. Which is not horrible, but anything that could take off from Tylo would be way over engineered for the other moons. And I’m expecting to reuse the craft for Bop quite often after completing the exploration mission. I finally settled on the following design. Not only do I like the look of this craft better, it actually has better TWR and a 1 more meters per second in delta-V.

So now that I have my landing craft, I need to revisit my exploration ship. The current ship uses nuclear engines which run on liquid fuel only, whereas the motor on my landing craft requires LFO (liquid fuel and oxidier). So I’ll need to add a tank to the ship to allow refueling of the lander after it leaves a moon an docks. That will of course mean I need to adjust the fuel and motors on the exploration ship as well. It’s a lot of planning but that’s part of the fun of the game for me.

Here’s the completed lander with the Tylo descent module.

Blaugust 2015 Day 20

Rather than suffer the vagaries of a d4, I loaded up Kerbal Space Program last night. It’s kind of cheating on my multitasking experiment as KSP has basically been my primary game since October. Regardless, I spent the evening in the Vehicle Assembly Building working on my first Kerballed mission to Jool, which is the second most remote planet in the Kerbol system and the only gas giant. This isn’t my first trip to Jool, I’ve sent dozens of satellites and probes to survey Jool’s five moons, but it will be the first time I send Kerbals.

In my current career game I have a life support mod installed, so unlike in the stock game, I actually have to make sure I send enough supplies along to keep my Kerbals fed for the duration of the trip, which will take about 2 years travel out, 3 or 4 more waiting on a return windows, and another 2 back. Which is why there are four supply canisters and two greenhouses for recycling.

The current weight of the ship is nearly 100 tons, so I’ll have to send it into orbit in at least two pieces, which I don’t mind doing as I’ve practiced rendezvous and docking quite a bit. I think I’ve managed to build everything into the ship I wanted for the primary craft. The next step is to figure out a small lander so I can actually put a Kerbal on one or more of Jool’s moons.

The trick with all of this is to try and keep the part count as low as possible. Large part counts of 150 or more cause the game to lag down massively on my machine. The game is still playable, but it’s not much fun. This is my only complaint with Kerbal Space Program. I would love to be able to build and assemble large space stations and interplanetary ships, but part count lag takes a lot of the fun out of the process.