Difference between revisions of "Tutorial:How to get to Duna"
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#For a return to Kerbin, you MUST touch down with at least 1 large fuel tank and an engine with high specific impulse intact. | #For a return to Kerbin, you MUST touch down with at least 1 large fuel tank and an engine with high specific impulse intact. | ||
| + | The best way to describe something that can get off of Duna, is a ship somewhere between one that can take off from the Mun, and one that can take off from Kerbin. | ||
==== Middle Stage ==== | ==== Middle Stage ==== | ||
| − | This is the stage | + | This is the stage that will be doing a lot of the work. It must be capable of getting from Kerbin to Duna, and positioning your lander craft for the terminal descent. It must carry enough fuel for the roughly 1500 m/s DeltaV you will need to successfully pull this off. |
==== Lower Stage ==== | ==== Lower Stage ==== | ||
| − | This stage should take you at least into Kerbin's orbit if you hope to reach Duna. It will require sDunaral large thrusters to lift the interplanetary vehicle itself into orbit, probably assisted by some SRBs. | + | This stage should take you at least into Kerbin's orbit if you hope to reach Duna. It will require sDunaral large thrusters to lift the interplanetary vehicle itself into orbit, probably assisted by some SRBs. For reference, it should be about 1.5x bigger than what you would need for a 1 way trip to Eve. |
===Step 2 - Planetary Alignment=== | ===Step 2 - Planetary Alignment=== | ||
Revision as of 15:55, 1 October 2012
Contents
Traveling to Duna
Duna is Kerbin's second closest neighbor. After a successful landing on Eve, it is likely your next logical step. It perhaps the ideal planet for interplanetary voyages for several reasons:
- It's close proximity to Kerbin.
- It's small size and gravity well (comparable to The Mun).
- It's atmospheric composition is thick enough to support aerobraking, yet also thin enough to permit an ascent back to orbit.
- Possessing moon similar to Kerbin's, Ike, in addition to several mysterious Easter Egg locations.
With a little bit of luck, skill, and determination, you can successfully land on Duna and return to Kerbin, all in one ship, with ease.
Specifications
- Length: 1-3 hours
- Difficulty: Moderate/Hard
- For version: .17
Additionally, you will need a good understanding of orbital mechanics (see Tutorials section), angles, and a lot of patience.
Steps
Step 1 - Build Your Rocket
To perform a successful landing on Duna you will need a large rocket. Unless you are planning to deploy a spaceplane in the Dunan atmosphere (a perfectly viable option), you will need something resembling a highly beefed-up Mun Rocket.
Upper Stage
Balancing this stage is tricky. Largely similar to a Mun lander, with several key differences:
- With proper parachute rigging, it will require little/no thrust for a landing (though save at least one parachute for Kerbin!)
- For a return to Kerbin, you MUST touch down with at least 1 large fuel tank and an engine with high specific impulse intact.
The best way to describe something that can get off of Duna, is a ship somewhere between one that can take off from the Mun, and one that can take off from Kerbin.
Middle Stage
This is the stage that will be doing a lot of the work. It must be capable of getting from Kerbin to Duna, and positioning your lander craft for the terminal descent. It must carry enough fuel for the roughly 1500 m/s DeltaV you will need to successfully pull this off.
Lower Stage
This stage should take you at least into Kerbin's orbit if you hope to reach Duna. It will require sDunaral large thrusters to lift the interplanetary vehicle itself into orbit, probably assisted by some SRBs. For reference, it should be about 1.5x bigger than what you would need for a 1 way trip to Eve.
Step 2 - Planetary Alignment
While not absolutely essential, the easiest and fastest way to reach Duna from Kerbin is ensuring that they are properly aligned. Otherwise, you may spend a lot of time (possibly years) and fuel drifting until they happen to match up.
To do so, check your map and make sure that Duna is behind Kerbin in it's orbit around Kerbol, and if you were to draw a line from Duna to Kerbol to Kerbin, it would form a ~60 degree angle. From this angle, you can get to a height of 200km around Kerbin, orbit retrograde until Duna is directly behind Kerbin, and burn until you have reached a velocity of roughly 3000m/s for a direct path to Duna.
Alternatively, you can visit The Interplanetary Guide and Calculator to calculate your own path.
Step 3 - Launch to Kerbin Orbit
Take off as usual (see Tutorials for how to achiDuna orbit), only tilt your craft heading east instead of the usual west. Unless you've done your own calculations, try to aim for a circular equatorial orbit spinning clockwise at around 200,000 meters.
Important Note: Sling-shotting around Kerbin to planets with a lower Kerbolar orbit requires a retrograde orbit. The shortest and most fuel-efficient method of traveling to Duna is by traveling around Kerbin in a clockwise orbit, rather than the standard counterclockwise orbit. To do this will require a little extra fuel for the first stage, as you are flying against the spin of Kerbin.
Step 4 - Fly from Kerbin to Duna
If have successfully reached your desired orbit around Kerbin, begin your high-velocity burn. Keep an eye on your map, as mentioned about you will need to wait until Kerbin sits exactly between you and Duna, and get your velocity up to approximately 3060 m/s.
It's really important to watch the map while you are accelerating. As you accelerate your Kerbolar orbital path should move to intersect Duna's. If all goes well, there should be a brief moment where you are captured by Duna's gravity well right around the target velocity. Immediately cut your thrust. If you overshoot, just turn the craft around and do a slight retro burn until you are caught again.
This journey should take about 200+ days, so hit the warp key and enjoy the ride.
Step 5 - Arriving at Duna
When you enter Duna's sphere of influence you will almost certainly be traveling at escape velocity. Begin firing retro until you are in some kind of orbit, after you are caught it doesn't matter how far out you are.
Assuming that you are trying to save fuel we are going to be doing an aerobrake here. As shown on the information page, Duna's atmosphere begins around 100km, so we are going for a periapsis slightly lower than that. Unless you have an extremely wide orbit, going below 95km will probably result in an unplanned descent.
If you are not planning on landing, being a forward burn at the apoapsis (once it has reached the desired altitude) to circularize your orbit.
Step 6 - Land on Duna (Optional)
Adjust your orbital path to where you would like to land, and continue aerobraking to bleed off that extra velocity. Dunantually you will be caught on a terminal descent through the atmosphere. You will notice that due to the thicker and larger atmosphere than Kerbin's you will descend much more slowly. Deploy your chute(s) to slow down Dunan further. Lower whatDunar landing gear you brought with you and fire retrorockets if the chutes aren't slowing you down enough. Ultimately we're going for typically touchdown speed (6-12m/s).
Congratulations! You've landed on another planet!
