The big issue with any kinds of space technology is the power source and power density. If three quarters of the vessel is taken up by power generation to get a mediocre total, then all the other systems need to be more efficient (less cool stuff) in balance. Contraversely, if you can power the entire craft with something the size of a deck of cards that yields terawatts of power, you can afford to put more of other stuff and use systems that are less efficient.
Power generation is one of the primary difficulties in current space travel. All current systems utilize chemical-based propulsion (rockets) and have solar panels to assist in power generation. The problem with solar panels is that their relative energy production efficiency is limited, typically they only generate at around ten percent. What this means is that ten percent of the energy that hits the panels is generated into electricity. As far as space combat is concerned, solar panels are also extremely fragile, and increase the target profile (the size of the craft as a target, which makes it easier to hit). As an alternative, a number of early probes and devices such as Voyager used radioisotope thermoelectric generators (RTGs), which is a fancy way to say they have very radioactive material which produce heat and then convert that into electricity. This is a simple form of nuclear power generation. These types of generation were used only to produce electricity.
Other forms of nuclear power, both for propulsion and for electricity generation have been theorized. Nuclear fission is the primary method, which is the most well-explored nuclear technology. Pebble bed reactors, already more compact than a standard fission reactor, could be used to provide both power and propulsion. As a source of energy, nuclear power is much more compact than standard methods of power generation. Still, the current societal fears of radiation and ‘evil’ fission will likely make widespread use of nuclear power an uphill battle.
Other forms of power generation and storage have been theorized in science fiction as well as actual scientific articles. Fusion, often seen as the next step of nuclear power, is an often seen trope of military science fiction. The current hurdle is that a controllable, sustainable fusion reaction seems just out of our reach. In theory, it would only require hydrogen as fuel to produce power. The issue is that making such a power system compact enough to use. This is likely to keep fusion power just out of reach. Antimatter power generation is often misconstrued. Antimatter, when combined with normal matter, annihilates one another. The issue, is that antimatter doesn’t occur naturally in our area (luckily for us, because if it did, we’d have a big explosion). So we have to generate it with something like the CERN collider. This, in effect, turns antimatter power into a high capacity battery, and not necessarily a high efficiency one. Containment of antimatter requires powerful electromagnetic fields, and any slip up would allow the antimatter to contact normal matter, and then you lose the battery and possibly the space craft. Other, even more esoteric power sources include singularities and dark matter, both of which are well beyond our current technology levels.
So why does all this matter? Well, as far as spacecraft design and warfare, power design is essential. A compact system allows more of the spacecraft’s volume and mass to be dedicated to other systems. More power allows more complicated systems and higher energy usage for those systems. Where this comes into play especially is in weapons, but also in sensors, communications, defenses, propulsion and support systems. A high energy weapon system such as a directed energy weapon (such as a laser) requires a lot of power, as would a rail gun or some other linear accelerator. The pay off for weapons like these are their destructive capabilities. Lower yield weapons require less power, but deal less damage. Rockets, missiles and the like have internal power and so the craft pays for them directly in additional mass and volume. The destructive capabilities of the spacecraft are hinged upon its ability to generate power and project it.
The other systems are integrated into this as well. A ship which dedicates all of its capabilities to offensive weapons may have to sacrifice other systems as a consequence. Energy requirements to sensors and communications are not entirely trivial, and they are essential for combat. Propulsion systems may utilize the ship’s power source or have their own internal power, but will likely use as much power or more as weapons systems, and a ship which cannot maneuver is an easy target. Defensive systems, which could range from jamming systems to smaller weapons designed to intercept enemy fire to the futuristic defense screens or shields will also be essential to combat and to the preservation of a vessel. Other systems are not as crucial. A warship may need to cut back on non-essential systems prior to combat, such as life support systems, internal lighting, and temperature control much like wooden hulled ships ‘cleared the decks’ of non-essential furniture and equipment prior to a battle.
In the near future, we are likely to see no drastic in power generation. Solar panels allow satellites to function with relative efficiency. If space combat does develop, solar panels will probably shift to use only on civilian or ‘neutral’ craft or installations. Nuclear power will most likely see use in near future space combat, both the RTGs and possibly pebble bed reactors. This will allow higher energy production and more powerful weapons (not counting those weapons such as missiles or rockets, which are internally sourced). More powerful weapons will likely require better defenses; either in the form of concealment (hiding) or hardening (make it tougher). And like that, the space arms race begins.
Thanks for reading. Next week Friday I’ll discuss space weaponry and where I foresee the issues and difficulties, as well as some of the benefits.