Aaron Pollyea’s Science Academy: RCS Propulsion in Star Trek

Star Trek Adventures Writer Aaron Pollyea talks the science of Star Trek

Welcome to the first of what I hope is many articles on Continuing Mission dealing with technology in the Star Trek universe. In this series, I plan on presenting ideas, technology, and conjecture on science and technology and how to fit them into your game, but shying away from stats and rules. The first of the subjects that I’d like to cover is spacecraft propulsion.

In Star Trek the vast majority of times we see spacecraft propulsion being used or spoken about it is in reference to warp drive for FTL speeds, and impulse drive for sub-light speeds. However, there is a long road going from where we are currently to what even the NX-class had available. Let’s break down some of these steps.

Reaction Control System (RCS) Thrusters

The most basic kind of propulsion is still found on all starships in the form of RCS thrusters. RCS thrusters can actually come in many different forms ranging from simple compressed gas to more complex exothermic reactions like those found on the old Mercury and Gemini capsules that used hydrazine fuel. When used in-game, these types of propulsion is generally limited in its duration or how much it can move a vessel, unless backed up by sizable reserves on a starship. EVA suits and very small craft could effectively utilize this type of propulsion, and anything larger than a WorkBee may only have these kinds of systems installed to use for fine maneuvers.

The Phoenix was an Earth spaceship used in the 21st century. It was the first Earth-made, manned spacecraft to achieve light speed using warp drive. The Phoenix was remembered as the ship that instigated Earth’s First Contact with Vulcans. [Courtesy of Memory Alpha]

A whole series of encyclopedic style tomes could be written on regular rocket propulsion, but these could be broken down into two major categories, solid and liquid propulsion. Solid rockets, like those found on the first stage of the Space Shuttle, are lit and burn until they run out of fuel. Liquid rockets can be throttled and sometimes relit after being shut down, but not always depending on design. Cochrane’s Phoenix sat atop a modified Titan missile that had a liquid fuel rocket using dinitrogen tetroxide, allowing it to be throttled for optimal control before the warp-capable vessel separated, but with the downside of being incredibly toxic and corrosive.

aaron3Gamemasters may want to utilize RCS propulsion systems in adventures where an engineer is very wet behind the ears and needs something simple to fix or learn. Remember, a finely tuned RCS thruster system means the difference between a gentle docking with another starship or starbase and the starship plowing through observation galleries and causing a major incident. These systems should almost be idiot-proof, but as with all pieces of technology, there will always be an idiot to make sure it breaks. Keep these systems simple, easy to understand, and utilize the example of a fire extinguisher being used to move a little robot around in space.

“A crewmember with a hobby revolving around building rocket pods for a shuttlecraft may find the XO of a starship wondering why caustic chemicals spilled all over the bay during the last conflict with the Xindi or Borg.”

Rocket propulsion can be found in use on just about any world that has made it past some form of industrialization in its simplest forms. But, unless characters are from a world that has just entered the Federation or are enthusiasts of old technology, most Starfleet crew members will have little to no experience with this kind of propulsion as shuttles and starships do not use them.

These types of propulsion tend to be dangerous as it often uses corrosive or dangerous chemicals to provide enough energy to lift or move a vehicle. A crewmember with a hobby revolving around building rocket pods for a shuttlecraft may find the XO of a starship wondering why caustic chemicals spilled all over the bay during the last conflict with the Xindi or Borg, causing incredible damage to the section even though weapons fire never came close to hitting near there.

One can easily find hundreds of examples of failed launches online to drive home the point that while it may be a lot of fun to have a little rocket capable to launching a Class-F shuttle out of the shuttlebay at 20 G’s, it’s often not safe to do so for the occupants of said shuttle, or the crewmembers having to serve anywhere nearby if the fuel ignites accidentally.

Just remember, if Captain Proton would like to have it on his rocket ship, it’s probably a good idea to ask the XO if it’s alright to practice your hobby.


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