Journey to Eve: My First Interplanetary Probe Mission [KSP]

Hello and welcome back to my blog!

It has been some time since my last post on Kerbal Space Program, a realistic space simulator game. Last time, I talked about setting up a space station on the second moon (Minmus) of our home planet.

Once I had a space station in the orbit of Minmus, it was easy to decouple the lander and land on multiple biomes on the surface and run different experiments. Landing and takeoff are easy on Minmus due to its relatively smaller size and no atmosphere. I even took the tourists in space and fulfilled their contract of landing on the surface of both Minmus and Mun.

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I was getting thousands of science points with these missions. This was the time when my science tech tree unlocked really fast, and I had better equipment like rocket engines, science experiments, etc., which enabled me to take on a much bigger project. This time, I was planning to go interplanetary.

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Eve, a tough planet to explore

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But it is not as easy as it sounds. Going to the moons of Kerbin is a different thing, and going to another planet is a completely different challenge. The most challenging is having enough fuel to get out of the sphere of influence of Kerbin and pass close to the surface of influence of the target planet. A good launch window can minimise that fuel cost. The closest planets were Eve and Duna. I chose to send an unmanned probe to Eve.

I didn't want to risk any of my astronauts in this mission. I wasn't even sure if I could make it back from there.

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My first Electric Propulsion Engine

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I unlocked a new engine, Ix-6315 "Dawn Electric Propulsion Engine", which provides an Isp of 4200s, which is the most efficient engine in the game. I thought it would be perfect for long-distance travel, but the only downside of this engine is its very low thrust of 2kN, meaning my burns would take much longer. But I was fine with it.

So, I designed the upper stage of the rocket with a lot of Xenon containers, which are the fuel required for this engine and all the scientific instruments to get as much science data as I can. I used one of the most powerful relay antennas in the game because I wasn't sure if the other antenna could send data over an interplanetary distance.

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It took me more than an in-game year to reach Eve, while it takes a few days to reach the nearest moon on the home planet. That tells you how far we had to travel to get to the next planet in the solar system.

Once I was in the SOI of Eve, I had to brake (or burn in the opposite direction) to get a capture and orbit the planet. It was not that easy with a just 2kN engine. I don't think one electric engine is good for these capture events. With the next mission, if I decide to set up a space station here, I would have to use much more powerful liquid engines.

Eve is an interesting challenge. I figured out quickly that it is not the easiest planet to travel on your first mission because its atmosphere is very thick, and it has 1.7 times more gravity than Kerbin. So, even a few kilometres into its atmosphere is enough to heat your probe and destroy it. Thanks to the quick save feature, otherwise this mission was doomed.

I wanted to take some readings inside its atmosphere and only managed to get a kilometre or so in its atmosphere. I can't imagine sending a lander here and getting it done. And lifting off from its surface sounds impossible to me at this moment.

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Exploring Gilly

Eve has only one moon called Gilly. It is one of the smallest celestial bodies to explore. It is a lumpy rock orbiting around Eve. It is not even spherical because of its low mass and size. It only has an equatorial radius of 13 km compared to 700 km of Eve. It has extremely low gravity. Only about 0.5% of that is on the surface of Kerbin (home planet).

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Landing on Gilly without Landing Gear

Because of how low the gravity is and an escape velocity of 35.7 m/s, I could use my low-thrust electric engine to even land on it. I didn't put any landing gears on my probe because I didn't know this moon would have this low gravity. If I knew, I would have put some light landing gear on it and safely landed. But I tried to land it anyway just to see if I could do it without damaging my engine. And it turned out to be an easy task. Even with 2kN of thrust, I could hover over the surface with no issues at all.

Landing became extremely easy; I had to just make sure I didn't damage my solar panels and the flat engine at the rear end. I am glad I put the more expensive retractable solar panels in this.

Running experiments while on the surface gives you even more science data. It had 3 different biomes, and I took readings from all of those and sent the science data back to the space centre.

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Once my experiments were done on Gilly, I put the probe back into a polar orbit on Eve. Now, it works as a relay satellite aiding in my future mission to Eve and beyond. I learnt a lot of things from this long and challenging mission.

My next target will be to reach the other neighbouring planet, Duna. That looks like an easier one compared to Eve. Let's see how it goes.