Realistic (and gamable) Space Travel

The biggest thing that I learned from Orbiter Space Simulator was how to accurately represent space travel realistically in a RPG.

The two key terms you need to know it delta-vee and time.

Delta-vee
This represent a change in velocity. For example to get into orbit you need to have enough fuel and thrust to go from zero to 7.8 km/sec. Sure if you doing it for real you have to have the right ascent trajectory so that when you hit the 7.8 km/sec mark everything is right to have a stable orbit. But for gaming all you care about is whether the character makes his piloting roll (or navigation depending on the system) and whether there is enough Delta-Vee to make that change in velocity.

All space maneuvers have a cost in delta-vee. So if you rate your fuel in delta-vee (instead of liters or kg) then you know how many of these maneuvers you can make. So if you on the moon of Alpha Leonis and want to goto Alpha Leonis. It may take a DV of 2.7 km/s to get into lunar orbit. Another 1.5 km/s to a trans-lunar trajectory to get to Alpha Leonis, and then a 3.5 km/s maneuver to achieve stable orbit around Alpha Leonis. So if you have fuel with a total of 7.7 km/s Delta-Vee in it then you have enough to make it the trip.

Time
Many Sci-fi systems have antigrav or some other superscience means of propulsion. In this case the limiting factor is time not fuel. In that you can only change your delta-vee by so much in X time. Normally this isn't a factor but if you are trying to catch someone that trying to escape that in a different orbital plane then it becomes critical.* Or if you coming in hot and trying to make a stable orbit in 2 minutes you may finding that you wished that you bought that 6G maneuver drive back on Efate.

*Changing the plane of your orbiter (the degree it is tilted to the planet's equator) requires 10 times the amount of delta-vee then simply raising and lower your orbit's altitude. This is why when there are mission to other planets or the ISS there is a window for the launch time. Mission Control is waiting for the orbital plane of the target to cross the launch site. Generally there is a couple of minute leeway on both sides. But the further you are off the more fuel (or time) it will take.

Orbiter Space Simulator 2010

I have another hobby (currently moribund while I work on publishing stuff) that involves programming add-ons for the Orbiter Space Simulator. This is not a game persay but rather a simulator similar to Microsoft Flight Simulator.

It can be used by people of different skill level and interests. The trick is that many of the default vessels are semi-realistic in that they are way overpowered compared to what we can really build. So they are lot more forgiving for novices getting the hang of orbiting and travelling in space. A realistic Space Shuttle is included as well as an orbiting International Space Station.

There are huge variety of add-ons at the Orbiter Hangar from my ultra realistic Mercury and Gemni to the fanciful. Note that Orbiter 2010 just has been released and many of the add-ons, my own included run better on the previous version Orbiter 2006. It still avaliable for download.

Best of all it all free.

My next GURPS session and Project Apollo

I will be trying out Twitter again when I play my next session of the GURPS Fantasy campaign. It will be starting on Monday July 20th around 6:30 eastern standard time.

Also don't forget that is also the 40th anniversary of the Apollo Moon Landing. If you have a hankering to try it for yourself, you can download the free Orbiter Space Simulator here. I also develop free add-ons for this which you see here. For wanting to try Apollo itself the most playable add-on is here and the most realistic add-on is here.

The difference between the two is that ASMO sticks with the Orbiter Space Simulator controls. Understand that Orbiter is a simulator not a game, but the author has wisely made a bunch of aids that allow novices to get going with realistic space flight. There still a bit of a learning curve.

In contrast NASSP's Project Apollo for Orbiter is designed so that you can take the original checklists and follow along doing exactly (or your own thing if you want) what the astronauts did. It even runs the original software for the various guidance computer.

Is is hard, in someways, but a ordinary person can learn to do it. The For the astronauts it wasn't technical difficulties of the training but being able to handle emergencies while accurately reporting what went wrong and what went right. To be able to do that under very stressful condition is a remarkable ability and is why 90% of the early astronauts were test pilots.

So come Monday, while follow my (mis)adventures at some point step out and take a look at the moon and remember the day that 40 years ago two men and a team of thousands brought fire to the moon.

Fire in the Sky here.