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Interplanetary Travel

Eventually everyone wants to leave earth behind and do some solar exploring. There are two methods for interplanetary travel. Direct point to point flying, star wars style, and the Hohmann transfer.

The direct method is preferred. It allows you to leave at any time and get to where your going as quick as possible. It is what we do every day going back and forth to work. Oh its not that fuel minded, we get off course turning this way and that wherever the road leads. Its also how we travel by plane let say going from New York to London in this case taking the most direct route but burning fuel the whole way to overcome gravity and astmoshereic drag.

Now in actual space travel the direct flight is never used. If you have launched and docked to any station you have already found this out. We are confined to the more fuel efficient methods. Here is why.

1. no  place to stop on the way and tank up
2. we need to take our oxygen as well as fuel with us
3. the most important , we must launch the full weight of all this out of the earths atmoshere.

These are the three main limitations of using chemical rocket engines.

Futuristic ships will have more powerful engines and won't be so limited. Most likely because they won't be chemical rockets. In the default Orbiter there are no futuristic ships with such Powerful engines.

- Atlantis, realistic model of Space Shuttle, LEO only, dock to station
- Shuttle A , futuristic heavy lift cargo ship, launch to a station only
- Delta Glider, Futuristic ship, with the ability to reach other planets,
- Dragonfly , space station builder, no atmospheric flight capabilities

As you can see without add-on ships the Delta Glider is the only ship capable of reaching the moon or other planets. Yet, the DG must use the Hohmann transfer method of space travel because of its low power chemical rocket engines. So what is the Hohman transfer? I think everyone who has flown in an airplane understands direct flight. Take off, aim for target, fire up engines. Hohmann transfers are not so simple. It works like this, while in orbit you burn progade until the eclipse is so large that apoapsis intersects the orbit of the target planet or moon. Once intersect accurs you quit burning and coast all the way there. As you can see there needs to be some planning for this type of flight. You need to aim your intersect to nail the target planet at the time of arrival. So a little bit a math is involved with the help of the Tran MFD. However a good flight computer can do the calculations for you. The TansX MFD is an add-on MFD worth obtaining. Duncan Sharpe has complete tutorials on using TransX MFD which is his creation. Now included in the base Orbiter download.

If you get a powerful add-on ship you can use the direct flight method for interplanetary flight. I like the Star Trek ship USS Voyager myself or the Millenium Falcon. However I recommend that any star ship captain know how to do a Hohmann transfer. It is one of the fundamental basics of space flight.

Related Links:

See Duncans Deep Space Manual

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