Jump to content

Optimal Descent (to the Mun)


Recommended Posts

I can\'t speak to the relative efficiency of my method because I haven\'t compared it analytically with other methods but I would bump my periapsis down to 10 km as soon as I cross the Mun\'s SOI by burning normal to the spacecraft\'s motion but within the plane of the hyperbolic orbit. I would then wait until reaching periapsis to close down my orbit because that would take maximum advantage of the Oberth effect.

If you had not posted that, I would have. I did the calculations a couple months ago and found this to be the most efficient.

Link to comment
Share on other sites

Thanks for the detailed responses and explanations - makes a lot of sense and this is something that should be in a Mun mission tutorial. I had been doing all my insertion burns tangential to velocity, but was beginning to realise that for the hyperbolic-to-orbit case that was less than optimal. I like your 'turning through the gate' analogy PakledHostage.

I have attached one of the few papers I found on the subject of efficient capture - a bit tough to read but the diagrams at the end are interesting. They find that a 3-burn maneuver may be optimal in some cases, where there is a plane change.

As for the next phase of the lunar landing challenge, my suggestion would be to

- start just outside the Munar SOI on a free-return type path - shorter duration challenge, fewer variables, but you can still choose a different SOI entry point if you want to.

- use the same craft we just used for this one, for comparison. Also, even though a low-impulse spacecraft would definitely change the optimal path, we\'d probably all end up using it at 100% or zero thrust anyway. At least with this 'typical' TWR spacecraft (for a lander) there is the possibility of doing some intermediate-thrust burns.

- allow free choice of landing site. This gives a greater variety of screenshots for one thing, and we\'ve seen some ingenious uses of terrain in this challenge already!

...but I\'m confident that it will be a good test of planning and piloting skills regardless.

Link to comment
Share on other sites

The new challenge is up (http://kerbalspaceprogram.com/forum/index.php?topic=15844.0), but I will still be monitoring (and probably attempting) this one. So if someone reading this is new to the challenge, you are still encouraged to participate. As I said in the original post, landing site and pilot skill are still a factor in the results.

Link to comment
Share on other sites

144.9 kg after an exciting flight through the gorge and landing on the high ground at the end. Wish I could have video captured it. I had set periapsis just below ground level so the 'gravity turn' was very flat.

I broke a lander leg but remained balanced on two at a precarious angle.

Link to comment
Share on other sites

This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...