TransX Retrograde sling of Jupiter

RisingFury

OBSP developer
Addon Developer
Joined
Aug 15, 2008
Messages
6,290
Reaction score
120
Points
153
Location
Among bits and Bytes...
Hi!

I've been playing around with TransX lately and managed to get some places, but now I'm trying to do a slingshot around Jupiter to lose as much of my Sun-relative velocity as possible and drop down towards the Sun, with a very low perihelion.

I'm guessing that when I got my close approach planned, I should reduce my prograde velocity to fall "under" the orbit of Jupiter, but no joy. Doesn't matter how I try to adjust it, my trajectory seems to leave the solar system.

I expected to be ejected very high up, possibly to Saturn or beyond... but I get ejected from the solar system instead.

Has anyone done this? Is it even possible?
 

the.punk

Advanced Orbinaut
Joined
Nov 3, 2008
Messages
1,031
Reaction score
0
Points
0
I think it must be possible.
Though, I haven't done that.
But also I think when you come with jupiters orbit around sun you gain vel from jupiter.
 

JamesG

Orbinaut
Joined
Jul 9, 2008
Messages
511
Reaction score
0
Points
0
Location
Afghanistan? WTF!?!
Working on your tan? :D

Are any Jovian moons shoving you along giving you more velocity than you expected? Of course TransX would account for that....

I donno. Look into the Messenger mission for a way of getting sunward without needing a trip to Jupiter, though at high time compression, you might get dizzy. :p
 

agentgonzo

Grounded since '09
Addon Developer
Joined
Feb 8, 2008
Messages
1,659
Reaction score
4
Points
0
Location
Hampshire, UK
Website
orbiter.quorg.org
Retrograde slings around jupiter have been done and aren't too hard to do. When looking at the Jupiter encounter stage, make sure that the inclination readout is over 90 deg so that it is retrograde - normally between about 170 and 210 deg. You should then see your projected orbit for the next stage have a perihelion much closer to the sun
 

RisingFury

OBSP developer
Addon Developer
Joined
Aug 15, 2008
Messages
6,290
Reaction score
120
Points
153
Location
Among bits and Bytes...
I think it must be possible.
Though, I haven't done that.
But also I think when you come with jupiters orbit around sun you gain vel from jupiter.

I'm not trying to gain velocity, I'm trying to lose it.

And it might not be possible... the change in velocity a sling can provide gets larger if you slng closer to the planet... but you can't sling closer then it's surface.

Although I haven't found any trajectory, not even one that flies through the planet.


As far as I understand it, MESSENGER used a resonant flyby maneuver at Mercury and Venus, which is currently out of my skill range...

Even so, I'm trying to enter a highly eccentric orbit around the Sun and I have much respect for Mr. Jupiter, so I thought a sling would be appropriate.
 

JamesG

Orbinaut
Joined
Jul 9, 2008
Messages
511
Reaction score
0
Points
0
Location
Afghanistan? WTF!?!
But also I think when you come with jupiters orbit around sun you gain vel from jupiter.

What he's trying to do is kill his velocity to just barely Jupiter's escape V to create effectively a highly elliptical orbit with the Sun and Jupiter at its apexes.

There was a probe that used this technique but I can't remember which it was...

What might be fun to try is to time a sling shot so that your trajectory has you pointed directly at the Sun at very high velocity for a close approach and then sling off the Sun. Then you can check to see if Orbiter has any built in relativty effects! LOL

I think both would need or at least be easier with a sling off Saturn to make the trajectory change not so severe.
 
Last edited:

RisingFury

OBSP developer
Addon Developer
Joined
Aug 15, 2008
Messages
6,290
Reaction score
120
Points
153
Location
Among bits and Bytes...
What might be fun to try is to time a sling shot so that your trajectory has you pointed directly at the Sun at very velocity for a close approach and then sling off the Sun. Then you can check to see if Orbiter has any built in relativty effects! LOL


Yea! That's very similar to what I want.

Relativistic effects indeed... my highest velocity reading with a DG was 0.086 AU, after deorbiting Mir and landing docked to it.
 

agentgonzo

Grounded since '09
Addon Developer
Joined
Feb 8, 2008
Messages
1,659
Reaction score
4
Points
0
Location
Hampshire, UK
Website
orbiter.quorg.org
See this scenario with the TransX (3.13) plan for a retrograde sling around Jupiter to get close to the sun:
Code:
BEGIN_DESC
Contains the latest simulation state.
END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 51981.6026756389
END_ENVIRONMENT

BEGIN_FOCUS
  Ship GL-01
END_FOCUS

BEGIN_CAMERA
  TARGET GL-01
  MODE Cockpit
  FOV 60.00
END_CAMERA

BEGIN_MFD Left
  TYPE User
  MODE TransX
  Ship  GL-01
  FNumber 4
  Int 1
  Orbit True
  Vector  3416560.2742 4555518.4666 -2857300.92224
  Vector  323.344845906 -99.1446969627 228.562435421
  Double  3.98600439969e+014
  Double  51981.6026753
  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  51981.6019673
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
Pe Distance
 0  7645212
Ej Orientation
 0  0
Equatorial view
0 0
Finvars
  Finish BaseFunction
  Int 2
  Orbit False
  Handle Sun
  Handle Earth
  Handle Jupiter
Select Target
 0 Jupiter
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  51981.6026747
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.
 1  9251.25811862
Eject date
 2  52162.3360335
Outward vel.
 0  0
Ch. plane vel.
 1  -2375.89272173
Finvars
  Finish BaseFunction
  Int 4
  Orbit True
  Vector  91651035138.5 34371776140.9 -459308486637
  Vector  -1496.60002061 -524.914885134 6978.1446986
  Double  1.26686534397e+017
  Double  52139.7796703
  Handle Jupiter
  Handle NULL
  Handle NULL
Select Target
 0 Escape
Autoplan
0 0
Plan type
0 1
Plan
0 0
Plan
0 1
Plan
0 0
Select Minor
 0 None
Manoeuvre mode
0 0
Base Orbit
0 0
Prograde vel.
 0  0
Man. date
 0  51981.602328
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
View Orbit
0 0
Finvars
  Finish BaseFunction
  Int 3
  Orbit True
  Vector  -711443188572 12220628179.1 420995070673
  Vector  -3298.77322906 -151.031135844 -4468.60716476
  Double  1.32839126489e+020
  Double  52887.5137465
  Handle Sun
  Handle Jupiter
  Handle NULL
Select Target
 0 None
Autoplan
0 0
Plan type
0 2
Plan
0 0
Plan
0 0
Plan
0 2
Select Minor
 0 None
Manoeuvre mode
0 0
Base Orbit
0 0
Prograde vel.
 0  0
Man. date
 0  51981.6026747
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
Velocity.
 0  0
Outward angle
 0  0
Inc. angle
 0  0
Inherit Vel.
0 0
Eject date
 0  52887.5137465
Finvars
  Finish BaseFunction
END_MFD

BEGIN_MFD Right
  TYPE User
  MODE TransX
END_MFD


BEGIN_SHIPS
ISS:ProjectAlpha_ISS
  STATUS Orbiting Earth
  RPOS 5142396.84 -4338821.76 228147.68
  RVEL -4757.778 -5518.127 2479.290
  AROT 30.00 -0.00 50.00
  IDS 0:588 10 1:586 10 2:584 10 3:582 10 4:580 10
  NAVFREQ 0 0
  XPDR 466
END
Mir
  STATUS Orbiting Earth
  RPOS -5386945.11 -240551.35 -3932979.85
  RVEL 4563.566 -380.598 -6222.730
  AROT 0.00 -45.00 90.00
  IDS 0:540 10 1:542 10 2:544 10
  XPDR 482
END
Luna-OB1:Wheel
  STATUS Orbiting Moon
  RPOS -123829.57 -2234552.36 -16.18
  RVEL 1477.842 -81.893 0.001
  AROT 0.00 0.00 176.11
  VROT 0.00 0.00 10.00
  IDS 0:560 10 1:564 10
  XPDR 494
END
GL-01:DeltaGlider
  STATUS Landed Earth
  BASE Cape Canaveral:1
  POS -80.6758964 28.5227640
  HEADING 150.00
  PRPLEVEL 0:1.000 1:1.000
  NAVFREQ 402 94 0 0
  XPDR 0
  GEAR 1 1.0000
END
SH-02:ShuttleA
  STATUS Landed Earth
  BASE Cape Canaveral:5
  POS -80.6745292 28.5197208
  HEADING 100.00
  PRPLEVEL 0:1.000 1:1.000
  NAVFREQ 0 0
  XPDR 0
  PODANGLE 0.0000 0.0000
  DOCKSTATE 0 0.0000
  AIRLOCK 0 0.0000
  GEAR 0 0.0000
  PAYLOAD MASS 6.0 0
END
END_SHIPS
 

JamesG

Orbinaut
Joined
Jul 9, 2008
Messages
511
Reaction score
0
Points
0
Location
Afghanistan? WTF!?!
Although I haven't found any trajectory, not even one that flies through the planet.

Have you tried setting up for an insertion and then "goosing" it a little bit just at perihelion, maybe after an orbit or two? That would allow you to "aim" your trajectory with regards to the Sun.

Not the most elegant solution, but it should work.
 

the.punk

Advanced Orbinaut
Joined
Nov 3, 2008
Messages
1,031
Reaction score
0
Points
0
I know that you want to lose velocity.
I wrote this because I think losing works the same just the oppostie way of the flight direction of jupiter.
 

flytandem

Tutorial Publisher
Tutorial Publisher
Joined
Oct 19, 2007
Messages
501
Reaction score
4
Points
0
Location
San Bernardino
Website
www.flytandem.com
Agentgonzo has a good example of doing a sling off jupiter to fall closer to the sun than you had come from before the sling. His sling will get you to a perihelion between that of Venus and Mercury.

A couple years back we had a challenge out to see how fast we could get a stock Deltaglider to go. It turned out the best way was to somehow fall to a low Pe just above the surface of the sun and do a prograde burn at that point. This meant to minimize the fuel used get to that point of falling at the sun. And it was very tough to even have any fuel left or even to fall to the sun in the first place. Couldn't do it directly off Jupiter as the encounter velocity needed to be more than 13Km/s to pull it off.

But slinging off Jupiter to another outer planet, even a second go at Jupiter allowed a sling that fell into the sun.

Isn't it funny how something that seems so simple, like hitting the sun, could be so hard.
 

kneejo

Astronut
Joined
Sep 20, 2009
Messages
88
Reaction score
0
Points
0
Location
Groningen
Website
www.myspace.com
when I returned from Neptune I went retrogarde around the sun, meeting the earth on the opposite site.. I did use 20k dV, so it wasn't really realistic, but at least I got back. :)
 

JamesG

Orbinaut
Joined
Jul 9, 2008
Messages
511
Reaction score
0
Points
0
Location
Afghanistan? WTF!?!
Or just materialize an entire Saturn V stack in an ecliptic orbit of Jupiter lined up and timed to perform the sling to sunward... :p
 

Eclipse1024

New member
Joined
Oct 24, 2009
Messages
1
Reaction score
0
Points
0
Isn't it funny how something that seems so simple, like hitting the sun, could be so hard.

I just started playing with Orbiter this week and before I found TransX or even bothered to read up on how to use the Transfer MFD properly, I attempted to do an Earth to Mercury flight.

I started by launching into a retrograde orbit of Earth, figuring that the prograde burn for Mercury would help bleed off some of my Solar orbit velocity. It seemed to work but it become apparent that I was heading no where near Mercury, and even if I could sync up orbits, the planet would still be on the other side of the Sun. So I aimed at the Sun instead as I was already crossing over it to reestablish a prograde orbit for Mercury.

I managed a fly-by without 10km, achieved a speed of 615M m/s (I think that's right), and did a prograde burn for Neptune when I realized I'd somehow lucked out on hitting it's launch window.

I jettisoned all crew but the pilot (I know, it's heartless, but I did so to save on O2) and after some early course corrections to align planes, I drifted cooly into an LNO, with nearly all fuel and O2 spent. Definitely a one-way trip.

Now that I have TransX, I may try this again, only doing so the right way this time. :)
 

flytandem

Tutorial Publisher
Tutorial Publisher
Joined
Oct 19, 2007
Messages
501
Reaction score
4
Points
0
Location
San Bernardino
Website
www.flytandem.com
I just started playing with Orbiter this week and before I found TransX or even bothered to read up on how to use the Transfer MFD properly, I attempted to do an Earth to Mercury flight.

I started by launching into a retrograde orbit of Earth, figuring that the prograde burn for Mercury would help bleed off some of my Solar orbit velocity. It seemed to work but it become apparent that I was heading no where near Mercury, and even if I could sync up orbits, the planet would still be on the other side of the Sun. So I aimed at the Sun instead as I was already crossing over it to reestablish a prograde orbit for Mercury.

I managed a fly-by without 10km, achieved a speed of 615M m/s (I think that's right), and did a prograde burn for Neptune when I realized I'd somehow lucked out on hitting it's launch window.

I jettisoned all crew but the pilot (I know, it's heartless, but I did so to save on O2) and after some early course corrections to align planes, I drifted cooly into an LNO, with nearly all fuel and O2 spent. Definitely a one-way trip.

Now that I have TransX, I may try this again, only doing so the right way this time. :)

Fun reading. Somewhat reminiscent.
I found that as I got more and more practice I would get more detailed and precise in the planning and execution of the flights. Therefore it took longer and longer at the computer to do a flight even though my fuel used was generally less and less. Extrapolated out far enough, I figure it will take forever to get nowhere.
:cheers:
 
Top