Messenger Probe

[slenderman666]

Has anyone tried to get to Moho using the flight path of the real life MESSENGER probe? I'm wondering because I've had KSP since .25 and Moho is still a b**** to get to, even with nukes. If anyone has tried this please tell me how you did it (i.e how the planets were aligned) and if anyone has any other ways to get to Moho please feel free to share.  

[nikyname]

sorry i am a noob

[Dfthu]

I just get into LKO, burn to escape, then stop engines right after I get escape, then I fiddle around with a maneuver node for a while and I get it.

Edited March 30, 2016 by Dfthu

[SaturnianBlue]

I once did a full recreation of the mission, but in the end I had to modify the orbit of my MESSENGER in hyperedit because the way the orbits were, there were huge inclination differences, and the probe kept swooping past Moho at high speed, so the orbit insertion wasn't legitimate, but the rest is.

 

In a nutshell-

Launch a kerbal year before a Eve transfer window, come back to Kerbin an year later.

Use Kerbin to curve you towards Eve.

Use Eve to come back to Eve one Eve year later.

Have a trajectory to intercept Moho.

Of course, those were the only steps I could recreate.

[Jetski]

8 hours ago, slenderman666 said:

Has anyone tried to get to Moho using the flight path of the real life MESSENGER probe? I'm wondering because I've had KSP since .25 and Moho is still a b**** to get to, even with nukes. If anyone has tried this please tell me how you did it (i.e how the planets were aligned) and if anyone has any other ways to get to Moho please feel free to share.  

In KSP, as well as in Real Life, there are a few ways to get to Moho more efficiently. 

1. Use Oberth Effect as much as possible: do your main burn close to Kerbin with a high TWR stage, or do several Pe bumps if using something less powerful.  Much less dV to get your first bump out of the system and on your way.
2. Use Eve.  Use flybys like Messenger to give yourself a bonus on the way.  First bump out of Kerbin should only aim to get you to Eve, or even Kerbin second rotation if you are hardcore and love maths. Particularly useful to modify your inclination to match evil Moho - fly below Eve to bring your trajectory sharply up, just like burning North at a descending node, or vice versa.
3. Use ion engines if possible.  The solar panel output is insane from Eve on in, so skip the Gigantors and pack extra xenon.  2 regular folding panels can run 2-3 ion drives no problem, even possible to use OX-STATS if you don't mind keeping them pointed the right way. Otherwise it's nukes in asparagus staging if you have a big ship.
4. Plan to meet Moho when it is going the slowest, at the Ap of the elliptical orbit and with planes matched already in deep space.  This turns those 6-10K braking burns into a regular 1-2K

 A regular Hoffman transfer will be really expensive - burning into Kerbol SOI then matching planes is asking for a 10K dV burn at the very least.

This guy did Moho easily (and most of a Grand Tour with a few extra cans of xenon) The top pancake is the lander, the bottom has a big xenon tank docked to it. Bill travels in style (lander can) between planets.

Edited March 30, 2016 by Jetski

[PLAD]

There was a challenge to get from Kerbal to a Moho landing with as little dV as possible a while back. It is here. In the end a messenger-style path was used as it was best. The real probe flew by Venus twice then Mercury twice and entered Mercury orbit on its third pass, Metaphor did 8 flybys of Moho to cut his arrival speed down incredibly low. If you look closely at the albums you can figure out at what times they launched and did their flybys. Note that back then there was only Earth time (24 hour days/365 day years). It took a lot more dV to get into Kerbin orbit back then too, so take that into account in your dV estimates for a modern mission. Some other people have done Messenger-style trips since then, but no one has ever beaten Metaphor's trip. That strategy of flying by Mercury and then doing a deep-space maneuver to correct for your next Mercury flyby is hard. (For me anyway!) But it can cut the total dV required by 30% over a standard Hohmann trip.