| Earth to Mars Checklist The Cpt. CryBaby Way Last Updated 19Jul2012 |
This is a step-by-step procedure for getting to mars from earth in the Orbiter Space Flight Sim using the
TransX MFD. Many thanks to Duncan and his successors for this excellent navigational tool. As always,
where would we be without Martin? He has made the world a better place and there are damn few people who
can say that.
This checklist is aimed at first-time inter-planetary travelers. As a relatively inexperienced astrogator,
I don't claim to be an expert. In fact, the more I learn about orbiter the less I know (if you know what I mean).
All I'm saying is that the following procedure gets me to mars. This checklist is based on the tutorials and
manual posted on Duncan's site as well as other tutorials across the internet. I've filled in some of the holes
with a more detailed checklist based on my limited experiences. Admittedly, this checklist wanders so please
take it with a grain. Experienced navigators can provide corrections where I've strayed or fallen short.
Everyone is welcome to add/comment. I will post all relevant feedback.
This checklist is printer friendly with low ink usage. To that end the screengrabs of the mfd have been
inverted in photoshop. The colors will be off but they are still accurate. Please keep in mind that the diagrams
are here for reference and what you are seeing in your scenario will be different. Use the graphs for their
concepts NOT their details.
I apologize in advance for all type-Os, spelling and usage errors. My writing sux but I think the points get
across to the reader.
This checklist assumes familiarity with the basics of orbital mechanics. If you haven't docked with the ISS a
couple times, then much of this won't make sense. Don't get ahead of yourself.
If you've flown from my earlier checklist, be prepared for some changes. I've simplified where I could and
added where necessary.
PRE FLIGHT:
Make sure you've turned fuel consumption off in the launch pad or are flying a ship with low fuel consumption
characteristics. Almost any ship will work with this tutorial as long as it has RCS control (both rotational and
linear thrusters) and relatively powerful forward thrust. If you can find one with a retro engine your life will be
easier but it is not necessary. Pick a scenario that has your ship landed on or orbiting earth.
FLIGHT PLAN:
1. After launching Orbiter, switch to cockpit view and launch transx in the left mfd
(Lshift + j)
2. In the left mfd (Lmfd) ensure that 'view' is set to 'setup'. If it is not, cycle through view settings
(shift + w) until 'setup' is selected.
Note: Most variables in the transx are selected by cycling through a list of available variables. Each list is of
different lengths so the instruction of "(shift + w)" means "cycle through the list using 'shift + w' until the
appropriate value is selected." This will clean up the checklist by excluding instructions of "do this twice" or
"cycle until" etc. etc. You're just going to have to pay attention! :)
3. In the Lmfd change 'select target' to 'escape' (Lshift + '+') [which means hold down the left shift key and hit
the '+' key until 'escape' is displayed.]
4. Create a new stage (Lshift + f)
5. Select target planet 'mars' (Lshift + '+'). The inside blue circle is earth's orbit. The outside blue circle is
mars' orbit. The sun is the "+" at the center. The straight blue lines intersect the orbits showing where the
planets are.
6. Change 'view' to 'eject plan' (Lshift + w)
7. Select 'prograde vel' variable (Lshift + >)
8. Increase the value of 'prograde vel' (Lshift + '+') to see the hypothetical orbit that this thrust would create.
Note: Right now we are simply setting up a hypothetical flight plan. Nothing we do now affects your ship until
we make a burn.
Continue to add thrust until the dashed orbit moves out from the earth and intersects with mars' orbit (the
outside blue circle). The most fuel efficient trip will be one where the orbit of your ship just barely reaches the
orbit of Mars (meaning it reaches mars' orbit but does not overshoot). If you overshoot, (Lshift + '-') will
decrease thrust and tighten your orbit.
9. Change variable to 'eject date' (Lshift + >)
10. Change the date by moving FORWARD (Lshift + '+') until the two straight dotted yellow lines match up.
You must move forward since you are trying to determine what your launch window will be in the future. As the
date is adjusted, the dashed lines might be coming together nicely and then they suddenly jump to totally new
positions. Orbital mechanics are fickle and sometimes they just can't seem to work out for a given situation.
Don't worry! Keep moving the date forward in time and eventually the lines will coincide (or get very close to
each other).
Note: Planetary orbits are ellipses and usually offset from each other. So as you rotate the date, you might
find that the hypothetical orbit (green dashed line) that previously reached out to Mar's orbit now falls short or
maybe overshoots. If this happens, jump back to step 7 and add or subtract thrust until the ship's orbit is
tangential to mars' orbit again.
During many steps of this process of getting to mars, it will be necessary to jump back and forth between steps
and variables to fine tune the flight plan. Changing one variable may throw an old variable out of whack so
you have to go back and adjust. Patience gets you to mars.
11. Continue to hop between and adjust the variables 'prograde vel' and 'eject date' & 'ch plane vel' variables
until 'cl. App' (closest approach) is as small a value as possible.
Note:
k = km
m = 1000km
g = 1,000,000km
t = 1 billionkm
12. Once you have 'Cl. App' at its lowest value, Go back to steps 7 thru 11 and pump up the sensitivity of
each variable by using (Lshift + {). This will allow you to trim down the distance even
more with fine tuning.
Note: The levels of sensitivity are:
course
medium
fine
super
ultra
hyper (if you are using Orbiter2010)
Please note: Don't labor too much on getting the 'Cl. App' to an unnecessarily low number. Chances are that
we'll be off on our burn and just a couple seconds variance will throw you off course and negate alot of your
tweaking. Anything between 100.0M and 300.0M is okay for your ejection burn. We'll tighten that up with
correction burns as we travel to destination.
13. Once you are satisfied that 'Cl. App' is as low as you are willing to get it, switch to "eject date' (Lshift + >)
and write down the MJD. See graph.
TransX MFD. Many thanks to Duncan and his successors for this excellent navigational tool. As always,
where would we be without Martin? He has made the world a better place and there are damn few people who
can say that.
This checklist is aimed at first-time inter-planetary travelers. As a relatively inexperienced astrogator,
I don't claim to be an expert. In fact, the more I learn about orbiter the less I know (if you know what I mean).
All I'm saying is that the following procedure gets me to mars. This checklist is based on the tutorials and
manual posted on Duncan's site as well as other tutorials across the internet. I've filled in some of the holes
with a more detailed checklist based on my limited experiences. Admittedly, this checklist wanders so please
take it with a grain. Experienced navigators can provide corrections where I've strayed or fallen short.
Everyone is welcome to add/comment. I will post all relevant feedback.
This checklist is printer friendly with low ink usage. To that end the screengrabs of the mfd have been
inverted in photoshop. The colors will be off but they are still accurate. Please keep in mind that the diagrams
are here for reference and what you are seeing in your scenario will be different. Use the graphs for their
concepts NOT their details.
I apologize in advance for all type-Os, spelling and usage errors. My writing sux but I think the points get
across to the reader.
This checklist assumes familiarity with the basics of orbital mechanics. If you haven't docked with the ISS a
couple times, then much of this won't make sense. Don't get ahead of yourself.
If you've flown from my earlier checklist, be prepared for some changes. I've simplified where I could and
added where necessary.
PRE FLIGHT:
Make sure you've turned fuel consumption off in the launch pad or are flying a ship with low fuel consumption
characteristics. Almost any ship will work with this tutorial as long as it has RCS control (both rotational and
linear thrusters) and relatively powerful forward thrust. If you can find one with a retro engine your life will be
easier but it is not necessary. Pick a scenario that has your ship landed on or orbiting earth.
FLIGHT PLAN:
1. After launching Orbiter, switch to cockpit view and launch transx in the left mfd
(Lshift + j)
2. In the left mfd (Lmfd) ensure that 'view' is set to 'setup'. If it is not, cycle through view settings
(shift + w) until 'setup' is selected.
Note: Most variables in the transx are selected by cycling through a list of available variables. Each list is of
different lengths so the instruction of "(shift + w)" means "cycle through the list using 'shift + w' until the
appropriate value is selected." This will clean up the checklist by excluding instructions of "do this twice" or
"cycle until" etc. etc. You're just going to have to pay attention! :)
3. In the Lmfd change 'select target' to 'escape' (Lshift + '+') [which means hold down the left shift key and hit
the '+' key until 'escape' is displayed.]
4. Create a new stage (Lshift + f)
5. Select target planet 'mars' (Lshift + '+'). The inside blue circle is earth's orbit. The outside blue circle is
mars' orbit. The sun is the "+" at the center. The straight blue lines intersect the orbits showing where the
planets are.
6. Change 'view' to 'eject plan' (Lshift + w)
7. Select 'prograde vel' variable (Lshift + >)
8. Increase the value of 'prograde vel' (Lshift + '+') to see the hypothetical orbit that this thrust would create.
Note: Right now we are simply setting up a hypothetical flight plan. Nothing we do now affects your ship until
we make a burn.
Continue to add thrust until the dashed orbit moves out from the earth and intersects with mars' orbit (the
outside blue circle). The most fuel efficient trip will be one where the orbit of your ship just barely reaches the
orbit of Mars (meaning it reaches mars' orbit but does not overshoot). If you overshoot, (Lshift + '-') will
decrease thrust and tighten your orbit.
9. Change variable to 'eject date' (Lshift + >)
10. Change the date by moving FORWARD (Lshift + '+') until the two straight dotted yellow lines match up.
You must move forward since you are trying to determine what your launch window will be in the future. As the
date is adjusted, the dashed lines might be coming together nicely and then they suddenly jump to totally new
positions. Orbital mechanics are fickle and sometimes they just can't seem to work out for a given situation.
Don't worry! Keep moving the date forward in time and eventually the lines will coincide (or get very close to
each other).
Note: Planetary orbits are ellipses and usually offset from each other. So as you rotate the date, you might
find that the hypothetical orbit (green dashed line) that previously reached out to Mar's orbit now falls short or
maybe overshoots. If this happens, jump back to step 7 and add or subtract thrust until the ship's orbit is
tangential to mars' orbit again.
During many steps of this process of getting to mars, it will be necessary to jump back and forth between steps
and variables to fine tune the flight plan. Changing one variable may throw an old variable out of whack so
you have to go back and adjust. Patience gets you to mars.
11. Continue to hop between and adjust the variables 'prograde vel' and 'eject date' & 'ch plane vel' variables
until 'cl. App' (closest approach) is as small a value as possible.
Note:
k = km
m = 1000km
g = 1,000,000km
t = 1 billionkm
12. Once you have 'Cl. App' at its lowest value, Go back to steps 7 thru 11 and pump up the sensitivity of
each variable by using (Lshift + {). This will allow you to trim down the distance even
more with fine tuning.
Note: The levels of sensitivity are:
course
medium
fine
super
ultra
hyper (if you are using Orbiter2010)
Please note: Don't labor too much on getting the 'Cl. App' to an unnecessarily low number. Chances are that
we'll be off on our burn and just a couple seconds variance will throw you off course and negate alot of your
tweaking. Anything between 100.0M and 300.0M is okay for your ejection burn. We'll tighten that up with
correction burns as we travel to destination.
13. Once you are satisfied that 'Cl. App' is as low as you are willing to get it, switch to "eject date' (Lshift + >)
and write down the MJD. See graph.
The details of your flight plan will be
different than what is shown in this graph.
Therefore your MJD date will be different
from what is shown here. Use the graphs
in this tutorial for their concepts, not
their details.
different than what is shown in this graph.
Therefore your MJD date will be different
from what is shown here. Use the graphs
in this tutorial for their concepts, not
their details.
14. Return to stage one (Lshift + r). You should now see a graph of the earth with the hypothetical orbit
represented as a curved dashed line.
15. Change 'view' to 'escape plan' (Lshift + w)
16. Change 'variable' to 'pe distance' (Lshift + >). This is where you set the distance of the periapsis
above the earth. Add or subtract (shift + '+' OR shift + '-') until 'pe distance' is 6.500 (6.5M). This will be a
very tight orbit just above earth's atmosphere (with a little wiggle room). Fine tune as needed (Lshift + {).
You may notice that this has shifted the hypothetical orbit (dashed curved line) to a position just above the
surface of the earth. The tighter your orbit the faster you will be going which will reduce your burn time.
Note: Your setup may show a dotted line that intersects earth on the graph. The graph is trying to relay
3-d information on a 2-d graph. As long as you've followed the instructions, this visual intersect will cause
no problems.
==
Congratulations! You've identified and recorded your launch window! You have also set up your flight
plan in the transx mfd.
Now all we have to do is follow through on that plan.
EJECTION BURN:
17. Exit Orbiter and 'save current' as E2M01.
18. Close out launch pad. Navigate your files and find E2M01 where it lives on your computer. For most
of us that will be:
start/my computer/local Disc C/Program Files/Orbiter/Scenarios
if you've got the latest version, replace 'Orbiter' with 'Orbiter2010'.
Your computer may have a different file structure. If you can't find the file, do a search.
19. Dbl click on E2M01. It should open in notepad. If it doesn't, launch notepad and then open the file
E2M01.
20. At the top of this document, you will see the line "Date MJD #####.#######". Change the MJD to just
BEFORE the launch window that you copied down in step 13 by subtracting .5 from the date
Example:
If you wrote down 52799.3435
Change MJD to 52798.843
21. Save this document using 'file' and 'save'. Do not rename it. Save it as the name it currently has
which should be E2M01. Exit Notepad.
The actions you just took will advance you to approx 1/2 day before your trans mars burn. Depending on
how far forward you set your date, this saves a lot of time acceleration.
22. Launch E2M01 in Orbiter. You are now 1/2 day away from optimum burn.
There are a few things left to do before we make our burn to mars so if you are not in orbit yet, get your
ship up and in orbit asap.
Note: We are taking liberties that won't work when flying a 'real' ship with limited fuel. There are ways to
optimize takeoff and align with the target at the same time. However, for simplicity, this checklist will break
these actions into separate steps. After you've gone to mars a couple times with this checklist, you can
research and experiment with ways to maximize efficiency.
23. Switch the view in the Lmfd to 'escape plan' (Lshft + w). Your ship is where the solid green straight
line intersects the solid green orbit. The grey straight line shows the points where your current orbital
plane intersects the orbital plane of your target (mars).
You will use this information in the next step as you would with the standard 'Align Orbital Plane' mfd to
align your orbital plane with mars' orbital plane.
24. Rotate your ship to '+normal' and time a burn to straddle either point where the grey line intersects
your orbit. The goal is to reduce 'R. Inc' to a value as close to zero as possible.
If 'R. Inc.' increases when you hit the gas, switch quickly to a retro thrusters. Fine tune with linear RCS
thrusters as needed.
Note: Unlike the standard 'Align Orbital Plane' mfd, the duration and timing of the alignment burn are not
computed for you. Use what you have learned about the 'Align Orbital Plane' mfd to make your best guess
about when to initiate this burn. It will take 2 or more burns to get 'R. Inc.' down as close as possible to
zero. If you will be making an extended burn (more than 20 degrees) change your Rmfd to orbital (set PRJ
to Shp) and monitor to ensure you don't accidentally de-orbit. Some add-on craft are not balanced and
burning normal or anti-normal can alter your orbit.
25. Set your right mfd to 'orbital' (Rshift + o). Change the projection to ship by hitting the 'PRJ' button
until 'SHP' is displayed in the uppe right. The next time you reach apoapsis, execute the necessary burn to
move your periapsis to the predetermined altitude of 6500 (see step 16).
26. The next time you reach periapsis, execute the necessary burn to move your apoapsis to an altitude
of 6500. This means that your Ecc will be zero or very close to zero. Circular orbits are finicky, this may
take a few touch-up burns.
27. Exit Orbiter and 'save current' as E2M02. It is a good idea to save at this point in case something
goes wrong with the burn. Should things go wrong, you can go back and relaunch from this point.
28. Launch your newly saved scenario (E2M02). Ensure your ship is oriented to 'prograde' ([). Set your
right mfd to transx (Rshift + j) but advance it to stage 2 (Rshift + f) while leaving the left mfd in stage 1.
Use 'Lshit + w' to change the view to 'escape plan'in your Lmfd. Monitor the countdown on stage 1 of the
Lmfd. In the lower left of that readout is a variable called 'T to Pe' (time to periapsis) This is the
countdown to burn. When this countdown reaches zero, (at the appropriate MJD that was written down in
step 13) as you approach the periapsis (green dotted straight line) initiate ejection burn.
Note: A dead-on successful burn will actually have to be initiated prior to this time. The transx mfd is
unable to calculate correct burn initiation for all possible spacecraft. You can either make your best guess
and correct en-route with maneuver burns or you can save the scenario just prior to burn so you can
relaunch and adjust if the burn isn't just right.
For example, I initiate burn 60 seconds before 'T to Pe'. The idea is to get the solid green curved line
(actual orbit) aligned with the dotted green curved line (hypothetical or target orbit). Don't worry if you are
off by a little bit. Just get it close and we'll correct our course as we go. Correction burns are a fact of life.
I'd bet it all that even NASA has never hit a bullseye on interplanetary travel launch.
During this burn you will see your orbit expand away from earth in the Lmfd. After your burn breaks you
out of earth's gravity the graph will change to a solar-centirc graph. Now you can see your orbit expand
out from earth's orbit to mars' in the Rmfd.
Note: I've seen tutorials that advise you to turn off prograde when you hit periapsis and others that leave
it on. Personally, I start my burn early with prograde on and hit 'num pad 5' to kill prograde and rotation
when I hit my periapsis. You'll have to play around to determine what works best for you.
29. Continue to burn while monitoring 'DeltaV' in the left transx mfd. Burn until this value is as close to
zero as possible. You can alternately watch the right mfd and see the actual orbit (solid green) expanding
outward from earth orbit (blue) towards the hypothetical orbit (dashed green). This will help you anticipate
when to shut down the main burn and fine tune it with linear thrusters.
30. When 'DeltaV' is zero, or as close as you are willing to get it, shut down all engines. You are now on
the way to mars. Pick a port with the best view of earth. Crack open a cold one and enjoy the view as you
leave earth behind.
CORRECTION BURNS:
31. Keep an eye on the left transx mfd. When you have escaped the earth's influence, it will change
automatically to stage 2 and will look like the graph in the Rmfd. This is a good time to initiate the first
correction burn.
32. Switch 'view' to 'manoeuvre' (Lshift + w)
33. Turn 'manoeuvre mode' 'on' (Lshift + '+')
34. Advance the right mfd to the encounter (Rshift + f). Set view to 'encounter' (Rshift + w). This will
display your projected arrival at Mars.
35 Because you want to make your correction burn right away, do not advance 'man date' very far into
the future. Just a nudge will do. Change variable to 'man date' (Lshift + >). Reduce the sensitivity to 'fine'
(Lshift + {). Quickly tap Lshift + '+' to nudge the burn slightly into the future. For this first burn you could
even leave it unadjusted. The distance you travel between now and your burn will be almost insignificant
to the computations.
36. Similar to what you did in your initial set up, Use the variables (prograde vel, outward vel, ch plane).
Adjust each to bring 'cl. app' to smallest value. (Shift + '+' OR Shift + '-') as needed. (Shift + {) will adjust
the sensitivity of these variables for fine tuning. (Again, don't labor too much on getting a low value. We
are still a long ways out so pinpoint accuracy will be hard to come by. The closer we get to our target, the
more important a low 'Cl. App' will be. For now, let good enough be good enough.
37. When cl. App is as low as you are willing to get it, switch 'view' to 'target' (LShift + w)
38. Using rotational RCS thrusters, rotate ship until the green "x" centers in the graph.
39. Watch the 'time to mnvre' readout and when it counts down to zero, fire engines until 'Rel V' is as
close to zero as possible. Use linear RCS thrusters to fine tune. Sticklers can use the RCS thrusters while
holding down the 'control' key for 1/10th bursts.
40. Change view to 'manoeuvre' (Lshift + w). Change variable to 'manoeuvre mode' (Lshift + >). Turn
'manoeuvre mode' off (Lshift + '+').
Important note: The 'manoeuvre mode' should be turned off when it isn't being used to perform a
correction burn. If you don't reset the mode between burns, you'll be planning your burn using information
that is days maybe even weeks old.
41. As you progress to mars, small course corrections can be accomplished with linear thrusters. Point
ship to prograde ( [ ). Fire linear thrusters as needed to reduce 'Cl. App' to its lowest value.
Note: After prolonged time acceleration these small thruster corrections may become ineffective. If so, go
through steps 32-40 to perform a major correction burn.
42. Make corrections (using steps 32 - 40 or step 41) as needed to keep 'cl. App' as low as possible.
43. Monitor your progress:
Set your Lmfd to transx (LShift + J)
The inside blue circle is earth's orbit. The solid blue line shows where earth is on that orbit.
The outside blue circle is mars' orbit. The solid blue line shows where mars is on that orbit.
The solid green ellipse is your ship's orbit. The solid green line shows where your ship is on that
orbit.
The grey line indicates the point of intercept as computed by all your actions up to this time using the
transx mfd.
A good rule of thumb is to make a new correction burn every time you cover half of the remaining distance
to your intercept. This will put more corrections closer to Mars where they help the most.
Once you are over halfway to Mars it is a good idea to start seeking more accuracy in your burns. As you
adjust your variables for a burn, be conscious of the Rmfd which has been advanced to the next
(encounter) step. At a minimum, you want your orbit (green line) to be visible on this graph. The closer
you get, the larger you want Mars to be on this graph--not just an X but a circle. Ideally you should shoot
for something just above 3.490m for 'Cl App'.
Be patient. Continue to correct your course and wait for the intercept point. Once you can see mars, you
will be tempted to point your nose at it and try to 'rocket' on over. This might work by accident when
approaching the ISS but taking this action on a planetary scale will get you lost in space. Distance and
direction are deceptive in space. Don't trust your eyes, trust your flight plan.
Remember, you aren't actually flying AT Mars. You are flying to a point in space that both you and Mars
will reach at the same time. If you flew directly at Mars, by the time you got there, it would have moved.
Also, be sure to let your flight plan play out. Many times I've checked my graph and determined that
something was wrong. There seemed to be no way that a rendezvous would happen. Yet, when I played
them out I was surprised to see that everything worked out as planned in TransX.
ENCOUNTER:
44. Keep watch on your graph. When the blue, green and grey straight lines are about to line up, you are
close to the intercept point. See graph.
represented as a curved dashed line.
15. Change 'view' to 'escape plan' (Lshift + w)
16. Change 'variable' to 'pe distance' (Lshift + >). This is where you set the distance of the periapsis
above the earth. Add or subtract (shift + '+' OR shift + '-') until 'pe distance' is 6.500 (6.5M). This will be a
very tight orbit just above earth's atmosphere (with a little wiggle room). Fine tune as needed (Lshift + {).
You may notice that this has shifted the hypothetical orbit (dashed curved line) to a position just above the
surface of the earth. The tighter your orbit the faster you will be going which will reduce your burn time.
Note: Your setup may show a dotted line that intersects earth on the graph. The graph is trying to relay
3-d information on a 2-d graph. As long as you've followed the instructions, this visual intersect will cause
no problems.
==
Congratulations! You've identified and recorded your launch window! You have also set up your flight
plan in the transx mfd.
Now all we have to do is follow through on that plan.
EJECTION BURN:
17. Exit Orbiter and 'save current' as E2M01.
18. Close out launch pad. Navigate your files and find E2M01 where it lives on your computer. For most
of us that will be:
start/my computer/local Disc C/Program Files/Orbiter/Scenarios
if you've got the latest version, replace 'Orbiter' with 'Orbiter2010'.
Your computer may have a different file structure. If you can't find the file, do a search.
19. Dbl click on E2M01. It should open in notepad. If it doesn't, launch notepad and then open the file
E2M01.
20. At the top of this document, you will see the line "Date MJD #####.#######". Change the MJD to just
BEFORE the launch window that you copied down in step 13 by subtracting .5 from the date
Example:
If you wrote down 52799.3435
Change MJD to 52798.843
21. Save this document using 'file' and 'save'. Do not rename it. Save it as the name it currently has
which should be E2M01. Exit Notepad.
The actions you just took will advance you to approx 1/2 day before your trans mars burn. Depending on
how far forward you set your date, this saves a lot of time acceleration.
22. Launch E2M01 in Orbiter. You are now 1/2 day away from optimum burn.
There are a few things left to do before we make our burn to mars so if you are not in orbit yet, get your
ship up and in orbit asap.
Note: We are taking liberties that won't work when flying a 'real' ship with limited fuel. There are ways to
optimize takeoff and align with the target at the same time. However, for simplicity, this checklist will break
these actions into separate steps. After you've gone to mars a couple times with this checklist, you can
research and experiment with ways to maximize efficiency.
23. Switch the view in the Lmfd to 'escape plan' (Lshft + w). Your ship is where the solid green straight
line intersects the solid green orbit. The grey straight line shows the points where your current orbital
plane intersects the orbital plane of your target (mars).
You will use this information in the next step as you would with the standard 'Align Orbital Plane' mfd to
align your orbital plane with mars' orbital plane.
24. Rotate your ship to '+normal' and time a burn to straddle either point where the grey line intersects
your orbit. The goal is to reduce 'R. Inc' to a value as close to zero as possible.
If 'R. Inc.' increases when you hit the gas, switch quickly to a retro thrusters. Fine tune with linear RCS
thrusters as needed.
Note: Unlike the standard 'Align Orbital Plane' mfd, the duration and timing of the alignment burn are not
computed for you. Use what you have learned about the 'Align Orbital Plane' mfd to make your best guess
about when to initiate this burn. It will take 2 or more burns to get 'R. Inc.' down as close as possible to
zero. If you will be making an extended burn (more than 20 degrees) change your Rmfd to orbital (set PRJ
to Shp) and monitor to ensure you don't accidentally de-orbit. Some add-on craft are not balanced and
burning normal or anti-normal can alter your orbit.
25. Set your right mfd to 'orbital' (Rshift + o). Change the projection to ship by hitting the 'PRJ' button
until 'SHP' is displayed in the uppe right. The next time you reach apoapsis, execute the necessary burn to
move your periapsis to the predetermined altitude of 6500 (see step 16).
26. The next time you reach periapsis, execute the necessary burn to move your apoapsis to an altitude
of 6500. This means that your Ecc will be zero or very close to zero. Circular orbits are finicky, this may
take a few touch-up burns.
27. Exit Orbiter and 'save current' as E2M02. It is a good idea to save at this point in case something
goes wrong with the burn. Should things go wrong, you can go back and relaunch from this point.
28. Launch your newly saved scenario (E2M02). Ensure your ship is oriented to 'prograde' ([). Set your
right mfd to transx (Rshift + j) but advance it to stage 2 (Rshift + f) while leaving the left mfd in stage 1.
Use 'Lshit + w' to change the view to 'escape plan'in your Lmfd. Monitor the countdown on stage 1 of the
Lmfd. In the lower left of that readout is a variable called 'T to Pe' (time to periapsis) This is the
countdown to burn. When this countdown reaches zero, (at the appropriate MJD that was written down in
step 13) as you approach the periapsis (green dotted straight line) initiate ejection burn.
Note: A dead-on successful burn will actually have to be initiated prior to this time. The transx mfd is
unable to calculate correct burn initiation for all possible spacecraft. You can either make your best guess
and correct en-route with maneuver burns or you can save the scenario just prior to burn so you can
relaunch and adjust if the burn isn't just right.
For example, I initiate burn 60 seconds before 'T to Pe'. The idea is to get the solid green curved line
(actual orbit) aligned with the dotted green curved line (hypothetical or target orbit). Don't worry if you are
off by a little bit. Just get it close and we'll correct our course as we go. Correction burns are a fact of life.
I'd bet it all that even NASA has never hit a bullseye on interplanetary travel launch.
During this burn you will see your orbit expand away from earth in the Lmfd. After your burn breaks you
out of earth's gravity the graph will change to a solar-centirc graph. Now you can see your orbit expand
out from earth's orbit to mars' in the Rmfd.
Note: I've seen tutorials that advise you to turn off prograde when you hit periapsis and others that leave
it on. Personally, I start my burn early with prograde on and hit 'num pad 5' to kill prograde and rotation
when I hit my periapsis. You'll have to play around to determine what works best for you.
29. Continue to burn while monitoring 'DeltaV' in the left transx mfd. Burn until this value is as close to
zero as possible. You can alternately watch the right mfd and see the actual orbit (solid green) expanding
outward from earth orbit (blue) towards the hypothetical orbit (dashed green). This will help you anticipate
when to shut down the main burn and fine tune it with linear thrusters.
30. When 'DeltaV' is zero, or as close as you are willing to get it, shut down all engines. You are now on
the way to mars. Pick a port with the best view of earth. Crack open a cold one and enjoy the view as you
leave earth behind.
CORRECTION BURNS:
31. Keep an eye on the left transx mfd. When you have escaped the earth's influence, it will change
automatically to stage 2 and will look like the graph in the Rmfd. This is a good time to initiate the first
correction burn.
32. Switch 'view' to 'manoeuvre' (Lshift + w)
33. Turn 'manoeuvre mode' 'on' (Lshift + '+')
34. Advance the right mfd to the encounter (Rshift + f). Set view to 'encounter' (Rshift + w). This will
display your projected arrival at Mars.
35 Because you want to make your correction burn right away, do not advance 'man date' very far into
the future. Just a nudge will do. Change variable to 'man date' (Lshift + >). Reduce the sensitivity to 'fine'
(Lshift + {). Quickly tap Lshift + '+' to nudge the burn slightly into the future. For this first burn you could
even leave it unadjusted. The distance you travel between now and your burn will be almost insignificant
to the computations.
36. Similar to what you did in your initial set up, Use the variables (prograde vel, outward vel, ch plane).
Adjust each to bring 'cl. app' to smallest value. (Shift + '+' OR Shift + '-') as needed. (Shift + {) will adjust
the sensitivity of these variables for fine tuning. (Again, don't labor too much on getting a low value. We
are still a long ways out so pinpoint accuracy will be hard to come by. The closer we get to our target, the
more important a low 'Cl. App' will be. For now, let good enough be good enough.
37. When cl. App is as low as you are willing to get it, switch 'view' to 'target' (LShift + w)
38. Using rotational RCS thrusters, rotate ship until the green "x" centers in the graph.
39. Watch the 'time to mnvre' readout and when it counts down to zero, fire engines until 'Rel V' is as
close to zero as possible. Use linear RCS thrusters to fine tune. Sticklers can use the RCS thrusters while
holding down the 'control' key for 1/10th bursts.
40. Change view to 'manoeuvre' (Lshift + w). Change variable to 'manoeuvre mode' (Lshift + >). Turn
'manoeuvre mode' off (Lshift + '+').
Important note: The 'manoeuvre mode' should be turned off when it isn't being used to perform a
correction burn. If you don't reset the mode between burns, you'll be planning your burn using information
that is days maybe even weeks old.
41. As you progress to mars, small course corrections can be accomplished with linear thrusters. Point
ship to prograde ( [ ). Fire linear thrusters as needed to reduce 'Cl. App' to its lowest value.
Note: After prolonged time acceleration these small thruster corrections may become ineffective. If so, go
through steps 32-40 to perform a major correction burn.
42. Make corrections (using steps 32 - 40 or step 41) as needed to keep 'cl. App' as low as possible.
43. Monitor your progress:
Set your Lmfd to transx (LShift + J)
The inside blue circle is earth's orbit. The solid blue line shows where earth is on that orbit.
The outside blue circle is mars' orbit. The solid blue line shows where mars is on that orbit.
The solid green ellipse is your ship's orbit. The solid green line shows where your ship is on that
orbit.
The grey line indicates the point of intercept as computed by all your actions up to this time using the
transx mfd.
A good rule of thumb is to make a new correction burn every time you cover half of the remaining distance
to your intercept. This will put more corrections closer to Mars where they help the most.
Once you are over halfway to Mars it is a good idea to start seeking more accuracy in your burns. As you
adjust your variables for a burn, be conscious of the Rmfd which has been advanced to the next
(encounter) step. At a minimum, you want your orbit (green line) to be visible on this graph. The closer
you get, the larger you want Mars to be on this graph--not just an X but a circle. Ideally you should shoot
for something just above 3.490m for 'Cl App'.
Be patient. Continue to correct your course and wait for the intercept point. Once you can see mars, you
will be tempted to point your nose at it and try to 'rocket' on over. This might work by accident when
approaching the ISS but taking this action on a planetary scale will get you lost in space. Distance and
direction are deceptive in space. Don't trust your eyes, trust your flight plan.
Remember, you aren't actually flying AT Mars. You are flying to a point in space that both you and Mars
will reach at the same time. If you flew directly at Mars, by the time you got there, it would have moved.
Also, be sure to let your flight plan play out. Many times I've checked my graph and determined that
something was wrong. There seemed to be no way that a rendezvous would happen. Yet, when I played
them out I was surprised to see that everything worked out as planned in TransX.
ENCOUNTER:
44. Keep watch on your graph. When the blue, green and grey straight lines are about to line up, you are
close to the intercept point. See graph.
45. Ensure that your current encounter is not an impact with Mars. This makes it very hard to set up your
encounter. See graphs below. Make your 'Cl. App' as close to 3.490m as you can without going lower.
This puts you just above Mars' atmosphere influence. Lower than that and your orbit begins to degrade
due to friction.
WARNING: On the long trip, you've probably gotten used to accelerating to some high time rates. Get
back into a close-in mind set and keep your time accelerations low or you'll zip right past Mars in a blink of
an eye. Just in case something goes wrong it may be a good idea to save a version at this point.
encounter. See graphs below. Make your 'Cl. App' as close to 3.490m as you can without going lower.
This puts you just above Mars' atmosphere influence. Lower than that and your orbit begins to degrade
due to friction.
WARNING: On the long trip, you've probably gotten used to accelerating to some high time rates. Get
back into a close-in mind set and keep your time accelerations low or you'll zip right past Mars in a blink of
an eye. Just in case something goes wrong it may be a good idea to save a version at this point.
46. When you enter Mars' gravitational influence, the MFDs will switch over automatically to the final step.
Slow your time acceleration. Carefully approach until you are approx. 4 - 6 planetary diameters away
from mars. You will have to eyeball this.
Note: It is a good idea to move in to this proximity so that Mars appears as a fairly large circle in the
graph. This aids in your visual set up for capture burn.
Slow your time acceleration. Carefully approach until you are approx. 4 - 6 planetary diameters away
from mars. You will have to eyeball this.
Note: It is a good idea to move in to this proximity so that Mars appears as a fairly large circle in the
graph. This aids in your visual set up for capture burn.
47. Don't forget to enjoy the view. There are lots of procedures going on here but take a minute to
admire the red planet. Make sure you are at time normal and don't gawk for too long.
Beautiful!
48. Set your Rmfd to the standard 'orbit' mfd. (Rshft + o). Make sure to hit the "PRJ" button in the upper
right to set the view to Shp (ship). Confirm in the Rmfd that your orbit is slightly above Mar's surface and
does not intersect the planet. If mars is not the reference body of your Rmfd (check upper left of mfd),
then assign it (Rshift + r) then select Mars.
Note: If your orbit trajectory intersects Mars, you've got to act fast. Quickly follow this procedure: A. Turn
Prograde. B. Swith to cockpit or internal view. C. Ensure Hud is in Orbit mode (H). D. Switch RCS to
linear. E. Fire in whichever direction will move your vector crosshair off of Mars surface the fastest. You
may have to burn for a long time with those wimpy thrusters. If RCS is taking too long, you'll have to do
some quick thinking, rotate your ship 90 degrees from prograde and make a main engine burn that moves
your vector off the planet. If you were paying attention in step 44, this wouldn't be an issue. :)
49. Switch Lmfd view to 'maneuver' (Lshift + W). Change variable to 'maneuver' (Lshift + >). Turn
maneuver mode on (LShift + '+').
50. You must now create a hypothetical retro burn that slows your ship down to a speed that allows Mars
to capture you. This can be a frustrating step the first few times you attempt it. The best advice is to
keep tweaking and pay attention to what your actions do to the graph. As with all other set ups,
'Lshift + {' and 'Lshift + }' will increase or decrease the adjustment amount of each variable.
Set variable to 'prograde vel' (Lshift + >). Reduce thrust (Lshift + '-'). You will see the hypothetical
dashed orbit bend around Mars, collapse and reform into an elongated ellipse as you decrease thrust.
This will require that you burn through a visual glich that happens when you go from a solar to a mars
centric orbit. Stay calm and keep reducing thrust until an elongated elipse forms around mars.
51. Switch the variable to 'man date' (Lshift + >). Set the sensitivity for this variable to 'ultra' (Lshift + {).
Slowly add to the date (Lshift + '+') until you see the elipse shift. Rock the elipse back and forth by adding
and subtracting time until it is centered around mars. See Graphs Below.
admire the red planet. Make sure you are at time normal and don't gawk for too long.
Beautiful!
48. Set your Rmfd to the standard 'orbit' mfd. (Rshft + o). Make sure to hit the "PRJ" button in the upper
right to set the view to Shp (ship). Confirm in the Rmfd that your orbit is slightly above Mar's surface and
does not intersect the planet. If mars is not the reference body of your Rmfd (check upper left of mfd),
then assign it (Rshift + r) then select Mars.
Note: If your orbit trajectory intersects Mars, you've got to act fast. Quickly follow this procedure: A. Turn
Prograde. B. Swith to cockpit or internal view. C. Ensure Hud is in Orbit mode (H). D. Switch RCS to
linear. E. Fire in whichever direction will move your vector crosshair off of Mars surface the fastest. You
may have to burn for a long time with those wimpy thrusters. If RCS is taking too long, you'll have to do
some quick thinking, rotate your ship 90 degrees from prograde and make a main engine burn that moves
your vector off the planet. If you were paying attention in step 44, this wouldn't be an issue. :)
49. Switch Lmfd view to 'maneuver' (Lshift + W). Change variable to 'maneuver' (Lshift + >). Turn
maneuver mode on (LShift + '+').
50. You must now create a hypothetical retro burn that slows your ship down to a speed that allows Mars
to capture you. This can be a frustrating step the first few times you attempt it. The best advice is to
keep tweaking and pay attention to what your actions do to the graph. As with all other set ups,
'Lshift + {' and 'Lshift + }' will increase or decrease the adjustment amount of each variable.
Set variable to 'prograde vel' (Lshift + >). Reduce thrust (Lshift + '-'). You will see the hypothetical
dashed orbit bend around Mars, collapse and reform into an elongated ellipse as you decrease thrust.
This will require that you burn through a visual glich that happens when you go from a solar to a mars
centric orbit. Stay calm and keep reducing thrust until an elongated elipse forms around mars.
51. Switch the variable to 'man date' (Lshift + >). Set the sensitivity for this variable to 'ultra' (Lshift + {).
Slowly add to the date (Lshift + '+') until you see the elipse shift. Rock the elipse back and forth by adding
and subtracting time until it is centered around mars. See Graphs Below.
52. Switch back to 'prograde vel' and add or subtract thrust to tighten the orbit around Mars.
53. Continue to tweak 'prograde vel' and 'man date' until you are happy with the encounter orbit. See
Graph Above.
54. Now we will perform the burn. Switch to 'target' view (Lshift + w). Use rotational RCS thrusters to
center the green X on the graph.
55. When 'T to Mnvr' counts down to zero, fire main engines.
56. Burn until 'Rel V' is zero. Remember the graph will freak out just a bit as you go from a solar to a
mars centric orbit. Stay calm and power through when this happens.
Note: Depending on the strength of your engines, you may need to hit the gas before the 'T to Mnvr'
reaches zero. Trans X cannot compute the burns for all craft. Practice with your ship and you'll get
intuitive about how much lead time you may need.
57. While burning to 'Rel V' zero, you should also keep an eye on your Rmfd which should still be set to
the standard 'orbit' mfd. Make sure your burn doesn't cause your orbit to intersect with Mar's surface. If
it looks like this is going to happen, interrupt the insertion burn. You'll have to swing out wide on one
orbit. Then burn at apogee and perigee to tighten your orbit.
58. You should be in familiar territory now due to your experience in earth orbit. On subsequent orbits at
periapsis and apoapsis refine your orbit to a low mars orbit. Be sure to keep it above 3.490m or your
orbit will slowly decay due to atmospheric drag.
59. Pat yourself on the back--You made it to mars.
==
DEBRIEF:
It wasn't the most efficient or most elegant trip. But our goal was to get to mars and this checklist should
have accomplished that. Use this experience to research and refine your interplanetary navigational
skills.
This checklist will work for traveling to all the outer planets, asteroids and other space bodies within the
solar system.
NOTE ON TRAVELING TO THE INNER PLANETS: As strange as it may seem, the same procedures
outlined here will also get you to the inner planets. The only difference is in step 8. Instead of increasing
thrust you must decrease it. Watch the graph and you'll see your ellipse dip down and extend toward
your target. Everything else works the same.
To return from the moon to earth using transx see flytandem's excellent tutorial.
53. Continue to tweak 'prograde vel' and 'man date' until you are happy with the encounter orbit. See
Graph Above.
54. Now we will perform the burn. Switch to 'target' view (Lshift + w). Use rotational RCS thrusters to
center the green X on the graph.
55. When 'T to Mnvr' counts down to zero, fire main engines.
56. Burn until 'Rel V' is zero. Remember the graph will freak out just a bit as you go from a solar to a
mars centric orbit. Stay calm and power through when this happens.
Note: Depending on the strength of your engines, you may need to hit the gas before the 'T to Mnvr'
reaches zero. Trans X cannot compute the burns for all craft. Practice with your ship and you'll get
intuitive about how much lead time you may need.
57. While burning to 'Rel V' zero, you should also keep an eye on your Rmfd which should still be set to
the standard 'orbit' mfd. Make sure your burn doesn't cause your orbit to intersect with Mar's surface. If
it looks like this is going to happen, interrupt the insertion burn. You'll have to swing out wide on one
orbit. Then burn at apogee and perigee to tighten your orbit.
58. You should be in familiar territory now due to your experience in earth orbit. On subsequent orbits at
periapsis and apoapsis refine your orbit to a low mars orbit. Be sure to keep it above 3.490m or your
orbit will slowly decay due to atmospheric drag.
59. Pat yourself on the back--You made it to mars.
==
DEBRIEF:
It wasn't the most efficient or most elegant trip. But our goal was to get to mars and this checklist should
have accomplished that. Use this experience to research and refine your interplanetary navigational
skills.
This checklist will work for traveling to all the outer planets, asteroids and other space bodies within the
solar system.
NOTE ON TRAVELING TO THE INNER PLANETS: As strange as it may seem, the same procedures
outlined here will also get you to the inner planets. The only difference is in step 8. Instead of increasing
thrust you must decrease it. Watch the graph and you'll see your ellipse dip down and extend toward
your target. Everything else works the same.
To return from the moon to earth using transx see flytandem's excellent tutorial.
