TransX Can't get to Mars

[DutchPlayer]

Hi,

TransX is messing with me. I planned everything to go to Mars. I've done everything what I learned. And after the ejectburn, I never get an encounter.

I don't understand, TransX will not take me to Mars. I'm sure I planned everything right. And I know I must perform MC's. But that's impossible, how can I correct something if Mars is 3056G off?

Hopefully someone can help me, I don't understand what I'm doing wrong.

Dutchplayer

 

[blixel]

I don't understand, TransX will not take me to Mars. I'm sure I planned everything right. And I know I must perform MC's. But that's impossible, how can I correct something if Mars is 3056G off

Did you mean you are off by 3.056G? If so, that's normal and can be fixed with a pretty small MCC. Rather than try to guess what you're having trouble with, let me just direct you to my Earth to Mars video series I made last August. It's not a tutorial. I just made the flight myself and recorded what I did. But maybe watching what I did will help.

If you're confident that you've done everything right up to and including the Eject burn, then you can skip to Part 6.

http://www.youtube.com/playlist?list=PL8A48A56E322B5F0D

 

[DutchPlayer]

I'm sorry about the closest approach its 169.9G (looked at wrong number sorry) But its still a huge diffrence.
Is this normal??

http://www.orbiter-forum.com/attachment.php?attachmentid=11359&stc=1&d=1361277808

 

[blixel]

I'm sorry about the closest approach its 169.9G (looked at wrong number sorry) But its still a huge diffrence.
Is this normal??

No, that definitely isn't normal. The two dashed orange lines should be right on top of each other. You are leaving Earth at the wrong time. You are arriving at Mars' orbit several months before Mars is there.

Earth should be "behind" Mars when you leave. In this graphic, Earth is just in front of Mars. It looks to me like you are leaving Earth about 30 to 60 days too late.

 

[DutchPlayer]

I planned everything out, but I get this as result of 10 minutes of planning. It's really weird.

BTW, I noticed by time to burn. If it hits 0, and I start burning, it go to 3000 seconds or so. This is confusing me a lot.

 

[DaveS]

I just watched your first MC, the 2 yellow lines are lined up in the video, as you can see on the picture it's not. If I want to correct this, takes me a lot of delta v. Thats what I don't understand. I planned everything out, but I get this as result of 10 minutes planning.

BTW, I noticed by time to burn. If it hits 0, and I start burning, it go to 3000 seconds or so. This is confusing me a lot.

DutchPlayer: Read blixel's post again. You launched after the launch window closed so you're arriving at Mars orbit after Mars has already been there.

So what you need to do is go back and try launching and doing the TMI when the launch window is actually open.

 

[blixel]

I just watched your first MC, the 2 yellow lines are lined up in the video, as you can see on the picture it's not. If I want to correct this, takes me a lot of delta v. Thats what I don't understand. I planned everything out, but I get this as result of 10 minutes planning

Your main problem is the date. If you go back to Parts 1 and 2 of my videos, I explain the importance of the date.

If you post the scenario you are using here, I'll open it up in Orbiter, make the necessary changes, and post it back here for you and explain what I did.

 

[DutchPlayer]

Ok, here you have it.

Before I've done anything:

http://www.orbiter-forum.com/attachment.php?attachmentid=11362&stc=1&d=1361279660

After the launch:

http://www.orbiter-forum.com/attachment.php?attachmentid=11363&stc=1&d=1361279702

And what is TMI

 

[blixel]

Ok. Your starting plan has a date of January 1, 2010. In order to go to Mars using a normal Hohmann transfer, you need to leave more like October 12, 2009. (Alternatively, you could go forward in time and leave on the same date as when NASA launched Curiosity, which would be around late November 2011.)

At any rate, since the starting scenario you provided didn't have a TransX plan to begin with, there's nothing I can offer in the way of telling you what you need to do differently. So instead, I just created a new plan from scratch using the right date.

Try this:

BEGIN_DESC
DG-IV on Runway, ready to launch from Wideawake International.
**This scenario requires Dan Steph's DG-IV addon to run.**
END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 55116.0013435187
END_ENVIRONMENT

BEGIN_FOCUS
  Ship GL-01
END_FOCUS

BEGIN_CAMERA
  TARGET GL-01
  MODE Extern
  POS 7.67 -0.23 -11.64
  TRACKMODE TargetRelative
  FOV 50.00
END_CAMERA

BEGIN_HUD
  TYPE Surface
END_HUD

BEGIN_MFD Left
  TYPE User
  MODE TransX
  Ship  GL-01
  FNumber 3
  Int 1
  Orbit True
  Vector  6270755.91965 -1090611.09014 279264.773048
  Vector  -50.3184432005 -181.871947962 419.61293884
  Double  3.98600439969e+014
  Double  55116.0013426
  Handle Earth
  Handle NULL
  Handle NULL
Select Target
 0 Escape
Autoplan
0 0
Plan type
0 0
Plan
0 1
Plan
0 0
Plan
0 0
Select Minor
 0 None
Manoeuvre mode
0 0
Base Orbit
0 0
Prograde vel.
 0  0
Man. date
 0  55116.0013424
Outward vel.
 0  0
Ch. plane vel.
 0  0
Intercept with
0 0
Orbits to Icept
0 0
Graph projection
0 3
Scale to view
0 0
Advanced
0 0
Pe Distance
 3  6571493.93694
Ej Orientation
 2  -0.240122398489
Equatorial view
0 0
Finvars
  Finish BaseFunction
  Int 2
  Orbit False
  Handle Sun
  Handle Earth
  Handle Mars
Select Target
 0 Mars
Autoplan
0 0
Plan type
0 2
Plan
0 0
Plan
0 0
Plan
0 1
Select Minor
 0 None
Manoeuvre mode
0 0
Base Orbit
0 1
Prograde vel.
 0  0
Man. date
 0  55116.0012931
Outward vel.
 0  0
Ch. plane vel.
 0  0
Intercept with
0 0
Orbits to Icept
0 0
Graph projection
0 0
Scale to view
0 0
Advanced
0 0
Prograde vel.
 0  3211.60810905
Eject date
 0  55116.1650052
Outward vel.
 0  0
Ch. plane vel.
 0  701.595437057
Finvars
  Finish BaseFunction
  Int 5
  Orbit True
  Vector  4040178307.11 -2577734069.86 -3321918578.13
  Vector  -1803.46517207 1154.0306678 1486.42793795
  Double  4.28282991638e+013
  Double  55395.5874599
  Handle Mars
  Handle NULL
  Handle NULL
Select Target
 0 None
Autoplan
0 0
Plan type
0 1
Plan
0 0
Plan
0 2
Plan
0 0
Select Minor
 0 None
Manoeuvre mode
0 0
Base Orbit
0 0
Prograde vel.
 0  0
Man. date
 0  55116.0013424
Outward vel.
 0  0
Ch. plane vel.
 0  0
Intercept with
0 0
Orbits to Icept
0 0
Graph projection
0 0
Scale to view
0 0
Advanced
0 0
Draw Base
0 0
Finvars
  Finish BaseFunction
END_MFD

BEGIN_MFD Right
  TYPE User
  MODE TransX
END_MFD

BEGIN_PANEL
END_PANEL


BEGIN_SHIPS
GL-01:DeltaGliderIV
  STATUS Landed Earth
  POS -14.4310100 -7.9719500
  HEADING 118.16
  RCSMODE 0
  PRPLEVEL 0:0.995 1:1.000 2:0.983
  IDS 0:45 100
  NAVFREQ 94 524
  XPDR 0
  ;-------------------------- Skin parameters must contain directory name of skin (without space) 
  MeshSkin Mining
  ;-------------------------- Cargo payload must contain name of config file or "none".(see doc) 
  CargoPayload none
  NOSECONE 0 0.00
  GEAR 1 1.00
  AllDoorsState 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 0 0 0.00
  But1Cockpit 0 0 0 2 2 2 0 2 2 2 2 2 2 2 2 1 1 2 1 1 1 5
  But2Cockpit 0 0 0 0 0 0 0 0 2 2 2 2 2 0 3 0 0 0 1 1 0 0
  TransEffect 0
  LifeBut1State 0 2 1 2 1 2 2 2 2 2 2 2 2 0 0
  LevelBatt 100.0002
  Emergency_power 10000.0000
  VoltageStartBus 0.0000
  VoltageGen1 96.2820
  VoltageGen2 96.2819
  VoltageGenBus 96.0000
  O2tankALevel 99.9639
  N2tankALevel 100.0000
  O2tankBLevel 100.0000
  N2tankBLevel 100.0000
  CabinO2Level 21.3875
  CabinCO2Level 600.0000
  CabinTempLevel 21.2000
  CabinPressure 14.7000
  CabinMoistLevel 36.0000
  CabinDustLevel 0.0001
  CabinO2Setting 21.4000
  CabinTempSetting 21.2000
  CabinPressSetting 14.7000
  AntennaTarget no_target
  O2ConsumptionSetting 1
  FuelConsumptionSetting 1
  MainenginePower 1
  ;------------------Crew parameters  UMMUCREW Function-Name-Age-CardiacPulse-WeightKg (fonction of Pilot must be: Capt) 
  NoOneOnBoard 0
  NoPilotOnBoard 0
  UMMUCREW Capt-Christopher_Coles-47-60-70
  UMMUCREW Spe-Burton_Lambert-22-66-78
  UMMUCREW Ast-Daniel_Gecker-33-72-75
  UMMUCREW Eng-Bradley_Banister-55-72-79
  UMMUCREW Spe-Bradley_Banister-36-65-82
  FailGearFailure 0
  FailGearCollapse 0
  FailLeftMainEngine 0
  FailRightMainEngine 0
  FailHoverEngine 0
  FailRcs 0
  FailSurfaceControl 0
  FailComputer 0
  FailComputerBlueScreen 0
  FailAutopilot 0
  FailExtRadiator 0
  FailAirbrake 0
  FailNoseCone 0
  FailCanopy 0
  FailAntenna 0
  FailLeftTurbo 0
  FailRightTurbo 0
  FailCargoDoor 0
  SpacesuitTimer 0
END
END_SHIPS

BEGIN_ExtMFD
END

 

[DutchPlayer]

Ok, thank you very much!! :thumbup:

If I want a good date, can I use one of the tools you suggested?

 

[blixel]

Ok, thank you very much!! :thumbup:

If I want a good date, can I use one of the tools you suggested?

There are a couple of tools on OH, such as [ame="http://orbithangar.com/searchid.php?ID=4439"]Trajectory Planner[/ame] and [ame="http://orbithangar.com/searchid.php?ID=5418"]Trajectory Optimization tool[/ame], there's also the Cosmic Train Schedule website, but I just use TransX to find the date.

 

[DutchPlayer]

Thank you Blixel, for the plan! I'm finally at Mars. My first time I went to Mars, credits to you to!

One final question: Must the refrence body beyond the target body?

 

[Ripley]

Launch windows ARE that important!!

Welcome to Mars :thumbup:

 

[blixel]

Thank you Blixel, for the plan! I'm finally at Mars. My first time I went to Mars, credits to you to!

Happy to help.

One final question: Must the refrence body beyond the target body?

I think there is a word or two missing from your question; I can't figure out what you're trying to ask.

 

[DutchPlayer]

What I'm asking is: how do I see (or know) when the launch window is open or not?

 

[Screamer7]

Why do you not try IMFD?
You do not have to worry about launch windows, although it can cost you a lot of fuel.

 

[blixel]

What I'm asking is: how do I see (or know) when the launch window is open or not?

When I brought up the scenario you sent me, I set up TransX and used the Eject date variable to find out when the two dashed yellow lines would line up.

This is a basic outline of the steps that I used to find the right time to launch.

 

[TMac3000]

What I'm asking is: how do I see (or know) when the launch window is open or not?

I use a simple rule: draw a line between your starting planet and the Sun, then draw a line between your destination and the Sun. If the angle between the two lines is about 90 degrees, then you have a launch window. If it's less than about 60 degrees, or more than about 120, then you need to wait

 

[sorindafabico]

For me, the rule of thumb have been intersecting orbital planes. The launch window occurs when plane change is minimal. And, of course, the position of planets allows the format of a Hohmann transfer (or almost).

If you use IMFD target intercept transfer, try to keep the numbers from EjA, InA and EIn/RIn near zero. EjA is your ejection angle from Earth; InA your injection angle at Mars; and EIn/RIn is the relative inclination between EjA and InA points.

You'll only get zero in both three if the orbits were circular and coplanar, probably, so don't worry if they are a little offset.

If you use transx, you can guess like blixel did. The main advantages of IMFD are its autopilot and map program, but transx is more user-friendly for planning.

You can save time using the already cited trajectory planning utilities and Cosmic Train Schedule website, they are great to find launch windows. I knew that of November 2011 (when MSL and Phobos-Grunt were launched), so I got the examples I'm posting here in a few minutes (just the time to fine-tune them).

In transx, I found this using only 2996 m/s of prograde, no outward or plane change:

But the IMFD example - got with Trajectory Optimization Tool - is, despite the longer trip, more fuel-wise if you are not intending to aerobrake.

 

[DutchPlayer]

When I brought up the scenario you sent me, I set up TransX and used the Eject date variable to find out when the two dashed yellow lines would line up.

This is a basic outline of the steps that I used to find the right time to launch.

Why do you reduce the eject date? I always advance the date (clicking +), is that wrong?

BTW, I understand the steps but I don't understand why you reduce the eject date.