Kerbin to Duna without orbiting

[maceemiller]

Hi all. Forgive this if its "the norm" yet this is what I did last night and I just have to tell you!

My normal route to any planet or moon is launch, then orbit. From there I use the protractor mod and leave kerbin at the exact time, however last night was different, purely because I was watching the protractor numbers reach where I wanted to burn prograde to Duna, however I'd not even launched yet, never mind be in a stable 100k orbit!

Panic struck in, so I launched, however I made a note of the protractor numbers just as a record. What happened next was for me anyway brilliant (and probably lucky!)

I've not been using the protractor mod long but I know enough that the first numbers you see (under an oval shape with a line through it) should be under 1.0..........mine was 0.22.

The next number, under the devil looking fork or a W with a line pointing down in the middle (im sorry for my vagueness, please check out the Protractor mod on YouTube) should be exactly 0.00 when you hit prograde yet mine was 8.00, due to my original error.

For me, a normal LKO is 100k so when my apoapsis reached that I shut down my engines and thought about my next move.

Putting my ship into orbit was out of the question now as id missed my window, so, as the W with the line it the middle hit 0.0 I fired the engines again and just went prograde......nothing to lose I thought.

By the time I had an intersect i was 158k from Duna apoapsis......

Entering Dunas SOI I didnt bother orbiting, then descending I just went for touch down and it worked!

I couldnt believe it! Woot Woot!!

A quick finale.....I returned home, only to mess the Kerbin reentry up, lose my parachutes due to burn up (my fault) however at 1.1km I EVA'd both Jeb and Bill, hit their RCS backpacks and hope for the best.......

Both, luckily hit the water, both were recovered and both are ready for their next mission......with me in command, I feel I should pay them more!!

Well, thats my last nights exploits.....I may just chill out and watch TV tonight.....

[Guest]

Well done.

[Rosco P. Coltrane]

haha. Nice.

For future reference, you don't need to leave when the "crossed-over-oval" is at 0º. You could have got into orbit and wait for the "pitchfork" to get to 0 again, some 30 minutes later in a 100 km orbit (you click those symbols to change numbers from angles to times). 30 minutes soon or late won't make the angle too far off the ideal.

[maceemiller]

haha. Nice.

For future reference, you don't need to leave when the "crossed-over-oval" is at 0º. You could have got into orbit and wait for the "pitchfork" to get to 0 again, some 30 minutes later in a 100 km orbit (you click those symbols to change numbers from angles to times). 30 minutes soon or late won't make the angle too far off the ideal.

Ahh ok thx! I just panicked but it worked....I may try this again to see if I can do it without orbiting every time.....an experimental stage if you will

[Guest]

haha. Nice.

For future reference, you don't need to leave when the "crossed-over-oval" is at 0º. You could have got into orbit and wait for the "pitchfork" to get to 0 again, some 30 minutes later in a 100 km orbit (you click those symbols to change numbers from angles to times). 30 minutes soon or late won't make the angle too far off the ideal.

Hell, even an Earth day or two off won't make much of a difference, I do that all the time.

[maceemiller]

Hell, even an Earth day or two off won't make much of a difference, I do that all the time.

Again, great to know. This is all new to me so I do appreciate all comments

[SkyRender]

Launch windows are usually fairly generous, especially for closer targets. This is exemplified with the Mun, actually: there's almost a full 45-degree fan of potential low-dV-cost encounters you can get with it each time you're close enough. Generally speaking, Duna launch windows tend to be a solid 30 Kerbin days long for especially good intercepts, and actually almost 150 days long for less-than-perfect intercepts (ie. within about a 33% margin of the ideal window).

EDIT: This is an invaluable planning tool for interplanetary and inter-lunar injections.

Edited July 16, 2015 by SkyRender

[Guest]

Well, if we're going there, this is the tool I use: http://alexmoon.github.io/ksp/

I find porkchop plots to be much more useful than phase angles but, like phase angles, I also use them as a suggestion since I generally find the maneuver given by the plot to be "off". Fudging is always involved, but it gives a really good indication of when to burn, how much you'll probably burn, and whether your inclination needs to be "up" or "down". Also remember that maneuver nodes are based off the assumption of an instantaneous impulse of the given magnitude and that a lengthy burn will mess them up to some extent.

You can find your ejection angle from a variety of means; Precise Node, Engineer, MechJeb, etc... I wrote a small tool for myself from my old Precise Node code since I actually prefer the stock maneuver node widget to the window that is PN.

[murdalok]

What you did is called a Direct Injection. Which is exactly what new horizons did on its way to Jupiter for a gravity assist. In theory direct injections should be more efficient (not by much) than going into a parking orbit. However , you must be very accurate with it.

[maceemiller]

What you did is called a Direct Injection. Which is exactly what new horizons did on its way to Jupiter for a gravity assist. In theory direct injections should be more efficient (not by much) than going into a parking orbit. However , you must be very accurate with it.

Wow! Ive learnt so much here. I will experiment however I do like a stable orbit. I just know where I am

[imaspacestation]

Eh? So the launch vehicle traveled to Pluto with the New Horizons satellite? What do they plan to do with it?

[murdalok]

Eh? So the launch vehicle traveled to Pluto with the New Horizons satellite? What do they plan to do with it?

The injection stage was jettisoned on the way to Jupiter , it will coast into interstellar space just like the probe itself.

[imaspacestation]

Is it expected to come back like a comet, or will it escape the system?

[murdalok]

Is it expected to come back like a comet, or will it escape the system?

Well there were two stages that left the Earths SOI. The first was the upper Centaur stage which helped the probe reach Earths escape velocity. This Centaur stage is now in a heliocentric orbit that reaches as far out as the asteroid belt. The final stage besides the probe itself was a solid booster known as a kicker. This kicker is what helped the probe reach escape velocity of the solar system before it was separated. This kicker should be coasting out of the solar system never to return.

[Vanamonde]

This report of a mission has been moved to Mission Reports.