Krash n Learn 3: Can we Build, Launch & Land on Duna Pole in 1 Hours?

[00:00:00]Crash and learn a mission free. Our target, Duna. Our mission, land on one of the icy poles. The time limit, 60 minutes. Let's go crash harder and learn faster.

[00:00:14]As always, before you start building your rocket for a mission, you need to know about the requirements of the mission, especially the delta V necessary to go where you want to go.

[00:00:22]So, let's bring up our favorite interactive delta V map and enter Kerbin as the start location and Duna as our target location. We can easily see that we need our usual 3,400 delta V for low Kerbin orbit. A transfer to Duna at an optimal transfer window will cost us around 1,700 delta V. When performed correctly, the Duna landing will cost no delta V at all. Why? Because you can use parachutes to land safely. Well, that only applies to most of the locations on Duna, but the poles are a bit special, as we will see later during the mission.

[00:00:57]Now that we know the delta V requirements, let's get started with building the rocket.

[00:01:02]This time we will only bring one Kerbal, so we pick the smallest command pod.

[00:01:06]For a proper lander, we of course need the following: a parachute, a heat shield, a decoupler, a tank, our favorite engine, the Terrier, and some landing legs. We place those on the four outer tanks to make the base of the lander wider and more stable.

[00:01:32]And something that is easily forgotten, when you land on a body with moderate to high gravity, add ladders so that your Kerbals can get back on the rocket and into the command pod.

[00:01:44]Just to be on the very safe side, let's add some solar panels for power generation.

[00:01:50]Now that the lander is done, let's put it into a nice fairing and continue with the transfer stage.

[00:01:56]We're going for the next tank diameter and the Terrier engine again. It gives us a nice thrust-weight ratio above one and we get about 2,000 Delta V out of it.

[00:02:06]Okay, next step, our first stage. That will bring us all the way to low carbon orbit. Yeah, that's right. We aim for a single stage to bring us to orbit. We go for the next bigger tank diameter and choose two Vector engines. They provide enough thrust for a thrust-weight ratio of 1.3 and close to 3,700 Delta V. That should get us to low carbon orbit. Let's go, first test launch. Ignition in 5 4 3 2 1 Liftoff.

[00:02:45]Ascent profile looking good as well.

[00:02:52]And we made it to orbit. Yay.

[00:02:55]Let's plot the Duna transfer. I didn't really pay attention in this test for a proper optimal Duna transfer window, but we should be fine. We just let MechJeb calculate the currently best possible transfer burn.

[00:03:13]>> [music] >> Since this is just a test flight, we can land anywhere on the surface, not necessarily the poles.

[00:04:01]>> And touchdown. The very first attempt is already successful.

[00:04:07]>> [snorts] >> Let's head back into Duna orbit again and check if we have enough delta V to even make it back to Kerbin maybe.

[00:04:30]Turns out we don't have enough delta V.

[00:04:32]Also, looking at the timer, we have already spent way too much time with the test flight. We only have about 13 minutes left for the real mission. So, this is our first learning in this crash and learn mission. Don't waste too much time performing the tests. Anyway, with 13 minutes left, let's attempt to speedrun the real attempt.

[00:04:53]Learning number two. Have you noticed that we landed only relying on the engine and totally not using the parachute?

[00:05:00]Yeah.

[00:05:01]We would need that single parachute on top of the capsule if we make it back to Kerbin and want to land there. So, we switch out the nose cones on the outer lander tanks with parachutes to use them during our Duna landing.

[00:05:13]Let me quickly show you how the transfer window planning works. Basically, you enter your start and destination locations and hit plot it. It will show you a nice diagram where the darker blue areas are the optimal times to launch for Duna and cost you the least amount of delta V.

[00:05:29]Once you reach the time of the launch window, Kerbal alarm clock even has a nice feature where it lets you visualize the launch angle. Okay, let's speedrun this.

[00:05:56]>> And time is up. Hands off the keyboard.

[00:06:00]Unfortunately, we only made it back to Duna's sphere of influence, but now the timer has hit zero. We did spend way too much time with the test run. Let's see what we learned in this episode.

[00:06:12]Actually, it is not that much in this episode because it was pretty much straightforward. Learning number one, watch the timer. Don't spend too much time testing. Learning number two, don't forget your parachutes.

[00:06:27]But the chat agreed with me that it would be nice to see if our rocket design could theoretically fulfill the mission. So, let's try it.

[00:06:35]We struggled a bit with finding the correct settings and timing for the parachutes, but in the end we found it and they worked nicely, saving us a lot of delta V during descent. The poles are apparently very high above sea level, so you don't get to do a full engine-less descent with only the parachutes. You still need to brake a bit.

[00:07:13]We finally landed on Duna's North Pole.

[00:07:16]Mission goal accomplished.

[00:07:28]But now let's find out if we can make it back to Kerbin.

[00:07:32]We are in orbit and we have about 600 delta V left. Whatever I tried, I couldn't find a maneuver that will bring us back to Kerbin with 600 delta V. So, we're basically stranded here in orbit around Duna.

[00:07:45]The chat and me agreed again that it would be nicer to be stranded on the surface of Duna instead of orbit.

[00:07:51]So, we performed another descent. Of course, only after redeploying all the parachutes.

[00:07:59]We chose that big crater at the edge of the North Pole for our landing zone this time.

[00:08:04]And we were not disappointed. This location made for some beautiful scenic camera shots.

[00:08:10]>> [music] >> So, in summary, crash and learn mission three in practice was a failure. We ran out of time, but in theory though, our vehicle was able to successfully perform the mission and land on Duna's pole, even get back to orbit. The main lesson learned here was not to waste too much time testing, but just go for the real [music] thing as soon as possible. I hope you enjoyed mission three of crash and learn and we see each other for mission four again. Sneak peek, Valentina is stranded in an inclined orbit around Kerbin with exactly zero fuel left. For sure, we need to rescue her, but we will only have the command chair available to do it. That's going to be a challenge. So, see you for mission four. Until then, crash harder, learn faster.