Flight Question Default MFD for interplanetary flight

[english]

Hello all!

Can you tell me if it is possible to use the default transfer MFD to get from Earth to Mars?

I've set the reference to be the Sun, and the target to Mars once I am in low earth orbit, however, it looks totally different to how it looks when trying to get to the moon.

What do the pros use on here, do they use the default or go with Transx? What are the benefits to using Transx over the default?

Thank's for any replies!

 

[garyw]

Transfer MFD only knows how to move you from a major body to a minor body so it can only work out an intercept for Mars when you are in solar orbit.

You would be better off using IMFD or TransX.

 

[english]

Transfer MFD only knows how to move you from a major body to a minor body so it can only work out an intercept for Mars when you are in solar orbit.

You would be better off using IMFD or TransX.

Thanks for that. Kind of feels like cheating though !?

 

[garyw]

How is IMFD or TransX cheating? It's what they are for....

Or you could work out the burn vectors and times by hand then try it in orbiter....! I know people have done that but my brain just about copes with orbits. :lol:

 

[Tacolev]

Yes it would be criminal to speak against the enriching experience of working out the trajectories yourself but that's a seperate experience in its own right. There's nothing "cheating" about TransX or IMFD and in fact you'll find that these tools become only even more helpful with a better understanding of orbital mechanics.

 

[english]

Cheers for the info guys, I'm going to give transx a try and see how I get on.

Mars here I come !

---------- Post added 08-04-11 at 07:18 PM ---------- Previous post was 08-03-11 at 08:44 PM ----------

Well, just as a small update, I went with IMFD, and it is definitely not cheating !

I've been following this http://www.youtube.com/user/thesnorklemonkey#p/search/0/XuS1GGAYm3I

I tried with IMFD 55 but I can't seem to get it to work, it seems to have been made more complicated.

So I opted for IMFD 422 which seems slightly more straightforward.

Anyway, the youtube tutorial above is useful for anyone else who wants to try this at some point.

 

[Tommy]

There's a lot of "missing" information in that video, lots of "use this number" without telling you how to get that number, etc.

For a beginner, I recommend reading the "Theory.pdf" from this tutorial: [ame="http://www.orbithangar.com/searchid.php?ID=5207"]IMFDTuto[/ame]

Then try the playbacks in this (which has a comprehensive manual, a useful reference for most questions you may come up with):[ame="http://www.orbithangar.com/searchid.php?ID=4142"]IMFD Full Manual/Playbacks[/ame]

IMFD 5.5 isn't really any more complicated than 4.22 - in fact it's easier, more accurate, and more fuel efficient. IMFD 4.22 won't even give you surface launch timing and heading, so it's about impossible to launch into the correct ejection plane (leading to a large plane change in LEO).

 

[english]

Many thanks for your reply.

I will give he new version of IMFD a try and see if I can get it to calculate me a course this time.

I managed to get to Mars with the default Delta Glider. I actually used the start of the Earth to Moon tutorial and then stopped the playback on the runway, as a starting point. I was passing Mars at around 150k and was starting to try to slow down, very nice view

The issue I had however was that I didn't have enough fuel to slow down, it was very close however, I would have been running on fumes to land. I got the Delta v down to around 4..... (can't quite remember the unit)? For the burn to Mars, but I had to make a few adjustments on the way.

My question I guess is..... does the default Delta glider have enough fuel on board to take off from Earth, and make it to Mars, with enough left over to slow down and land?

 

[astrosammy]

http://solo.dc3.com/orbiter/video/EuropaToCallisto/ With that one I finally learned how to use it.

 

[Tommy]

Many thanks for your reply.

I will give he new version of IMFD a try and see if I can get it to calculate me a course this time.

I managed to get to Mars with the default Delta Glider. I actually used the start of the Earth to Moon tutorial and then stopped the playback on the runway, as a starting point. I was passing Mars at around 150k and was starting to try to slow down, very nice view

The issue I had however was that I didn't have enough fuel to slow down, it was very close however, I would have been running on fumes to land. I got the Delta v down to around 4..... (can't quite remember the unit)? For the burn to Mars, but I had to make a few adjustments on the way.

My question I guess is..... does the default Delta glider have enough fuel on board to take off from Earth, and make it to Mars, with enough left over to slow down and land?

The Stock DG has enough fuel to get there and land - if you do it right. How did you select the launch window? In the video you linked to, he got "lucky" - the stock scenario he used coincides fairly closely to a good window - otherwise the instructions in that video won't help much.

IMFD can get you to another planet even if the window isn't very good - but it uses more fuel to do so. There is a simple, repeatable process to find an optimized launch window, and it can be found on page 30 of the IMFD Full manual I linked to above (in blue text).

IMFD comes with a bunch of playbacks - but you'll need to have the XR-2 for many of them.

The sequence is: (starting while landed)

1. Trajectory Planning - Target Intercept used to calculate transfer.
2. Launch Planning - Surface Launch , synced to Course. Then fast forward until Launch
3. Launch and ascent - Surface Launch used to attain lowest EIn.
4. Transfer Burn - Orbit Eject, synced to "Course"
5. MCC's (and plane change if required) - Target Intercept, set source to "x"
6. Approach - Planet Approach or Base Approach programs used - must be near Mars' SOI
7. Insert - Orbit Insert. Alternatively, in a stock DG you can use aerocapture instead of the insert burn by approaching with a PeA of about 30k and flying upside down so you can use the wings to keep you from climbing back out of the atmo. (You can extend the airbrakes, and just stay at 30k altitude, upside down, and use elevator trim to hold altitude.)

A significant reason 5.5 is more efficient than 4.22 is the Surface Launch program - which saves a lot of fuel by allowing you to launch into alignment with the ejection plane, and avoid an expensive plane change before (or during) ejection.