IMFD AppD Programs Summary

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IMFD Appendix C: Common Settings IMFD Manual Contents IMFD Appendix E: Checklists for Scenarios

Appendix D

This is a summary of all programs. It is also a description of when to use each one.

Map Program

Information: The Map Program is really not used to plan any trajectories. Rather, it predicts them and displays them. It uses a special trajectory prediction method that allows for extremely accurate predictions.

Used to:

  • Display your orbit and your target‘s orbit
  • Provide very accurate data on many different properties of your trajectory Appropriate to use when:
  • You are out of a Planet or Moon‘s SOI
  • You need an accurate periapsis prediction
  • You want to see where your trajectory is taking you
  • You need an accurate prediction of almost anything, from Periapsis Velocity to Delta Velocity required to circularize an orbit

Not appropriate to use when:

  • No instances where the Map Program really is not useful.

Helpful Hints:

  • Set up the Reference to the body that everything is orbiting (you, the body you left, and your target object).
  • Set target to your target.
  • Hit the SOI button and use CNT to center your spacecraft to see when you cross inside a planet‘s SOI.
  • Hmmm, Why is it that I have outer planets installed with all 62 of jupiter‘s moons, and I see the grey circles around Jupiter on the Map Program but there are only green orbits displayed for the four Galilean Moons? If this happens anywhere, you might want to decrease the Mass Limit in the configuration page. All objects will be displayed as little grey circles, but only objects with a mass greater than the mass limit will have an orbit displayed. The minimum value for Mass Limit is 1e15.
  • The Base Approach or Planet Approach Program may not give you entirely accurate predictions of PeA (altitude of periapsis). For the most accurate prediction possible by IMFD, set the Accuracy to 1.000 in the Map Configuration Page.
  • When far from a planet, predictions made by the Map Program of values such as PeA (Altitude of Periapsis) and PeT (Time to Periapsis) will be much more accurate than those made by MFD‘s such as Orbit MFD. However, as you get closer to a planet, Orbit MFD becomes more accurate, and can be used.

Target Intercept Program

Information: The Target Intercept Program is used to calculate your trajectory from one celestial body to another. It uses special trajectory prediction methods, and is extraordinarily accurate. Be careful, though, because the target it heads you for is the very center of the planet!!

Used to: Predict trajectories, plan flights, perform midcourse corrections, set up free return trajectories.

Appropriate to use when:

  • Making a Planet to Moon trip (Earth to Moon)
  • Making a Planet to Planet trip (Earth to Saturn)
  • Making a Moon to Moon trip (Europa to Io)
  • Performing a midcourse correction far from a planet (outside its SOI)
  • Viewing important information such as time to target intercept, and viewing a diagram of you, your target, and the planet or moon you left.

Not appropriate to use when:

  • Making a midcourse correction close to a planet. As stated above, the Target Intercept Program will try to make you head for the dead center of a planet.
  • Making a Moon to Planet trip (Moon to Earth, Phobos to Mars, etc.) Helpful Hints:
  • The Reference is the object that the body you leave and your target object both orbit (Reference is the Sun for an Earth to Mars trip because Earth and Mars orbit the sun).
  • The Source is the object that you leave (For the same trip Source would be Earth because you leave the Earth).
  • Target is the object you are trying to get to (For the same trip Target would be Mars because that is where you are going)
  • Whenever you leave a Planet‘s SOI, ALWAYS SET THE SOURCE TO YOURSELF!!!!!!! You can do this by pressing the SCR button and inputting ―x‖ without the quotations.
  • After you are just outside a planet‘s SOI, and you set the source to yourself, you might find the dV value (delta velocity for midcourse correction) quite large. This is because you are still near the planet. Time warp until dV hits a minimum value and starts to climb, THEN perform your first midcourse correction.
  • It is inefficient to just launch to any planet whenever you want. Open up Target Intercept, set your Target, Source, and Reference, open doors so the crew can breathe for a long time (DGIV, XR series) and open your radiator or turn on External cooling so you don‘t overheat (XR series), and time warp at 100,000x until oV hits a minimum and starts climbing. This is the day you should go to your desired planet.
  • Off-Plane is often the most inefficient way to get to a planet. If you are going for efficiency, use Target Plane, Two Plane, or Source Plane.
  • After setting the source to yourself when using Target Plane, set the mode to manual target!!! There is a bug that will allow the line of nodes to rotate, always keeping you 90 degrees from your plane change.

Tangential Transfer Program

Information: This program is not used very often.

Appropriate to use when:

  • You are trying to make a transfer with the minimum delta velocity. Not appropriate to use when:
  • You want to get to a planet quickly and don‘t feel like spending 20 minutes finding a perfect launch time.

Helpful Hints:

  • You may want to use the SET button instead of the + and – buttons, because often times you will have to adjust TEj a HUGE amount and you would be holding down the + and – buttons for a very long time.

Planet Approach Program

Information: This program is useful when you are approaching a planet. It allows you to set up select orbital elements for your approach orbit, and thus it is more efficient than eyeballing your approach via Map MFD and Orbit MFD.

Appropriate to use when:

  • You are near a planet (inside or just outside its SOI). You can do your first correction burn far from the SOI to minimize the dV of later correction burns, but your first burn may be inaccurate if you are too far.
  • You want to orbit a planet a certain number of times and then land perfectly aligned with a base.
  • You want to see a diagram of what your approach orbit looks like.
  • You are planning a trip from a moon to a planet. Not appropriate to use when:
  • You are not near your target planet
  • Any mid course corrections far from your target planet. For this use the Target Intercept Program.
  • You are too close to a planet. If you wait until you get too close to a planet to perform the burn to set up your planet approach, the dV value will be astronomically high.

Helpful Hints:

  • Set up and perform the first burn when you are outside the planet‘s Sphere of Influence. It will be inaccurate but it will decrease the magnitude of the upcoming burns.
  • Do several burns (Autoburn) in the course of approaching a planet; this keeps dV low. Once dV gets high and you get close to a planet, it can begin to increase very rapidly.

Orbit Insert Program

Information: This program is used to do a capture burn from a hyperbolic orbit.

Appropriate to use when:

  • You are near a planet with a hyperbolic orbit, and you want the computer to do your insertion burn for you instead of doing it manually so it is more accurate.

Not appropriate to use when:

  • Every other instance other than the one listed above.

Helpful Hints:

  • USE IMFD V4.2.1!!!!!!!! The Orbit Insert program in the later versions of IMFD is highly inaccurate, and it decreases your periapsis dramatically. For best results, have the current version of IMFD AND version 4.2.1. Use 4.2.1 for Orbit Insert and the latest version for everything else.
  • You should execute Autoburn far from the actual point it will perform your insertion burn. Autoburn controls time warp automatically, so you never have to worry about passing the planet by mistake because you forgot to turn down the time warp.

Delta Velocity Program

Information: This program is used to autoburn a set delta velocity value. It is rarely used.

Appropriate to use when:

  • You want an automated burn for a specific amount of delta velocity Not appropriate to use when:
  • Performing ejection burns
  • Performing insertion burns
  • Performing midcourse corrections
  • Basically, there is no real need to ever use this program.

Orbital Program

Information: This program does several very useful things when you are in orbit.

Appropriate to use when:

  • You want to circularize your orbit at your CURRENT altitude.
  • You want to match the velocity with a target orbiting with a low relative velocity to you so you can intercept it (Martian moon, space station, etc.)
  • You want to center a target in your front windshield.

Not appropriate to use when:

  • You are flying between two bodies that have their own gravity (planet to planet, planet to moon EXCEPT for situations similar to Phobos, Deimos, tiny moons close to outer planets such as Amalthea). Use Planet Approach and Orbit Insert to enter orbit around these larger bodies. So any moon that you cannot orbit around (Phobos, Deimos, tiny moons close to outer planets such as Amalthea) you should use the Match Velocity Mode and then land on the moon much as if it were a space station—move slowly towards it; its gravity will not tug you towards it.

Helpful Hints:

  • The circularize orbit mode will circularize your orbit at the altitude when the engines start firing. It will not wait for you to reach apoapsis or periapsis. When you hit autoburn, the burn starts immediately.
  • If you want to put a space station into view, and don‘t want to ―cheat‖ by using planetarium mode, use the Find Target mode.

Surface Launch Program

Information: This program helps you launch into a low orbit that is nearly ready to be ejected from.

Appropriate to use when:

  • You are on the ground waiting to launch.
  • You are ascending from the source planet (going to low earth orbit for an earth to mars trip)

Not appropriate to use when:

  • You are in orbit around anything anywhere. Basically, only use this program for the above cases.

Helpful Hints:

  • You can launch at any time. For the lowest EIn when you launch, wait until the yellow number counting down seconds reaches zero. This will happen twice per simulator day.
  • Leave this program up throughout your entire ascent. You can add left or right nose slip to keep the EIn number at a minimum.

Orbit Eject Program

Information: This program is used to eject from a low orbit onto an orbit created by another program.

Appropriate to use when:

  • You are in low orbit around a planet or moon, ready to eject to travel to your target planet or moon.

Not appropriate to use when:

  • Any other circumstance other than the one listed above. Helpful Hints:
  • Always use Off-Axis mode when you perform a long ejection burn. Then, after it has completed, switch to realtime mode and hit autoburn again to correct any mistake that the Autoburn made the first time. With very long burns, it is likely that Autoburn will not be able to make it perfectly.
  • Although you can get data from the Course, Base Approach, and Slingshot programs, you rarely use the latter two options—when flying to another planet, you almost always set up a course plan with target intercept, use surface launch to get into a low orbit, and use orbit eject to get on your way.

Base Approach

Information: Base Approach is used when you want to do a direct landing when you arrive at a planet, so you will not do an insertion burn and a deorbit burn. Either you will do a direct reentry (eliminating both of the above mentioned burns) or you will combine them (such as when you are approaching Brighton Beach on the Moon) into one long burn.

Appropriate to use when:

  • You are very far away from a planet.
  • You want to land directly and not orbit the target planet or moon. Not appropriate to use when:
  • You are making a midcourse correction VERY far from a planet. Use the Target Intercept Program to make midcourse corrections.
  • You want to orbit the target planet for some time (maybe for some sightseeing  )
  • Any other instance other than the ones mentioned in the Appropriate to use when list.

Helpful Hints:

  • You will not find a solution every time. If the program cannot find a solution, then no target orbit (purple) is displayed.
  • dV may be very large. This is the price to pay for landing directly. Again, if you do your first burn far away from the planet and use several smaller burns as you get closer, the dV is minimized.
  • Hint is time to periapsis. Do not trust Orbit MFD or anything else. Use the Map Program, with the accuracy set to 1.000.
  • Set Ant to 90 degrees for winged vehicles (DGIV, XR series, etc.) when approaching the Earth from the moon (elliptical). Set it to 120-160 degrees when approaching Earth from another planet (hyperbolic)
  • This program basically alters your orbit, thus altering the time at which your ship crosses the periapsis of a planet. As a result, you will find that it works best with planets with a fast rotation because a base on the surface will pass under your reentry or landing zone more often during your approach. It is difficult to get this program to work with planets or moons that rotate slowly.

Slingshot Program

Information: This program is used to change your course target by setting up a slingshot around a planet.

Appropriate to use when:

  • You are performing a slingshot around one planet enroute to another. Not appropriate to use when:
  • Any other instance other than the case mentioned above. This program will not plan a slingshot, it will simply set it up and autoburn so that your ship will fly by the planet on its way to the next planet.

Helpful Hints:

  • Once again, if you do your first burn far away from the planet and use several smaller burns as you get closer, the dV is minimized.
  • If doing slingshots around gas giants, once you are out of their SOI and you switch the source to self in target intercept, you may find dV quite high. That is because they are still influencing your orbit. Time warp until dV reaches a minimum and begins to climb, THEN perform your midcourse correction.
  • Slingshots are rarely more efficient than a direct transfer orbit (unless you are NASA and you calculate to launch on a very specific date when the planets are perfectly aligned for you). If you want to do a good slingshot, why not use NASA‘s dates? For example, do an Earth to Jupiter to Saturn around the time that Voyager 1 did it. Use Scenario Editor to go back in time
IMFD Appendix C: Common Settings IMFD Manual Contents IMFD Appendix E: Checklists for Scenarios