Tutorial: Viking 1
In this tutorial we will do our first interplanetary voyage. We are going to send a probe to Duna. The probe will consist of an orbiter and a lander. The lander will be equipped with lots of scientific payload so that we can collect some interesting facts about Duna.
Getting into orbit
We don't want to waste any of the landers monopropellant during the flight, so before you ignite right-click the landers monopropellant tank and click the green arrow to deactivate it. You could also already activate some of the sensors and watch them during the ascend when you are curious.
Use the first three stages to get into orbit.
Performing a gravity slingshot around Mün
In order to reach Duna with the propellant we have left in the 4th stage, we need to perform a gravity slingshot maneuver around Mün to catapult us out of Kerbins sphere of influence and on a higher orbit around the sun. This is explained in the separate gravity assist tutorial.
Going on a course to Duna
As soon as we left Kerbin, start to plan a descent maneuver to get onto an orbit to Duna. We can't afford to use more fuel than necessary, so pick the perfect spot on the orbit. When Duna is in a bad position at the moment, feel free to do a few orbits. Our probe is patient. A few years in orbit won't hurt it. Our target is small compared to the vast distance we have to travel, so plan and execute your descent precisely to get as close to Duna as possible.
Stopping in the Duna system
When you enter Duna's SoI you will likely be on a trajectory which leads you straight out of it. Unless you want your visit to Duna to be a very short one, you will need to get rid of a lot of your speed. There are three ways to do so:
- Just accelerate retrograde. This is the easiest way to do it, but also the most fuel-consuming. When you are lucky you have enough fuel to do this, but very likely you don't.
- Perform an aerobrake maneuver. Change our trajectory to go through Dunas atmosphere. The atmospheric drag will slow you down. This is easy and fuel-efficient, but it's also very risky. Get too close, and you will lose too much speed, go sub-orbital and create another crater. Don't get close enough and you will find yourself on an escape trajectory with no chance of returning. Duna's atmosphere starts at 40 km and is a lot less dense than Kerbins.
- Perform a gravitational slingshot around Ike. Just like you used a rendevouz with the Mün to accelerate out of Kerbin you can use Ike to decelerate at Duna. To do this, pass it closely when it's heading in the direction opposite of your own. This is the most elegant way to stop and gets you a glimpse at Ike as a bonus, but is also the most tricky one to pull of.
After you slowed down enough to do so, get into a circular orbit with a radius of about 50km around Duna, release the orbiter with the lander and enjoy the view.
Get the lander on the ground
After you did a few rotations and found an interesting spot to land, release the lander from the orbiter. USe the monopropellant of the lander to go onto a suborbital path and activate the parachute. Due to Duna's thin atmosphere it won't slow you down completely, so reduce your speed further using monopropellant. Then land just like you did with Luna 9.