What would interstellar war really look like? Part 4 - Tactics with natural space flight

After discussing the tactical challenges presented by interstellar war using an nearly-instantaneous transit system (NITS) form of transport, this post is going to look at what the problems of natural space flight (NSF) warfare might be in terms of tactics.

NSF transport essentially means that starships are used to move goods and people from one solar system to another. Then there is the challenge of moving them from space to the planet surface. Most science fiction uses some form of NSF to explain how people get from one solar system to another. In Star Trek, the problem of orbit-to-surface travel is solved using a short-range form of NITS, the transporter beam. The alternative is either to have the starships capable of flight in an atmosphere, or else to have separate vessels (shuttlecraft) that transport goods from orbiting starships down to the surface.

As discussed earlier, most space battles even in an interstellar war will take place in solar systems. One warring faction will seek to wrest control of the system from the other, either to take control of its useful resources or to deny them to the enemy. That means the objective will be to take control of any colony or colonies that have been established in the system.

As discussed in Part 1, colonies might be on hospitable planets, for example producing organic materials such as food, wood or organic fabric; or they might be on inhospitable worlds that for one reason or another (e.g. poisonous or non-existent atmosphere) cannot support human life without protection. Such worlds could include moons or large asteroids as well as planets. A third possibility is an artificial "hub" satellite that serves as a collection point for smaller vessels mining small asteroids that are too small to support the structures necessary for a human colony. Let's call the hospitable world colonies "H colonies" and those on inhospitable worlds, "I colonies". That makes the satellite-based colonies "J colonies" by alphabetic progression.

At first sight, it might seem that siege tactics would be effective against I and J colonies especially. However, in Part 1 I discussed that these colonies would still need to be self-sufficient for several months at a time. Hoping for essential life-support equipment to break down, or food supplies to run low, might take longer than is really practical - especially if the enemy is sending forces into the solar system to break the siege. Deliberately targeting the life-support systems would also be problematic if the objective is to gain control of the resources produced by the I or J colony, since after taking control of the facilities, those facilities would have to be repaired, or replaced entirely. If forcing the surrender of the colony is impractical, then it follows that somehow, entry to the sealed protective facilities must be achieved without simultaneously requiring large amounts of repair work to render the colony habitable again.

Defensive elements of an I or J colony's structure simply must include many airlocks dividing the colony into self-contained units. Not only because of the potential assault, but also because of the threat of natural events causing a breach. This means that simply piercing the protective shell and letting the inhospitable environs kill the inhabitants would be insufficient to gain control of the facilities.

The image that this leaves is of space-suited figures storming through metallic corridors and blasting their way through heavy doors - an image that is familiar from numerous "space opera" type movies and tv shows. But the same problem exists here as with the strike against life support systems: if the facility is to be usable afterwards, then the airlocks have to be easily repairable and not blasted to slag!

If the attackers want to gain use of the facilities to aid their war effort, therefore, then they cannot take them easily. Any direct assault on an I or J colony would necessarily be initially only to deny their resources to the enemy, and they could only be claimed for one's own side later, after the war has ended or the fighting has moved much further into territory formerly held by the enemy. As with NITS warfare, the aim will be not so much to prevent resources coming in, but to prevent them from leaving, whether by siege tactics or by destruction of the facilities. Accepting this, it is (of course) possible that the threat of destruction could be enough to persuade the colonists to surrender to the attacking forces, but for that to work the threat has to be credible, which means that the attacking commander has to be willing to destroy the colony to achieve his goals.

So much for satellites and inhospitable worlds. What of H colonies, though?

Obviously, if the world is hospitable, then it means both that the potential population of the colony is higher, and also the potential deployment of troops is more flexible. There is no limitation on where they can land except the need to be able to attack the colony itself easily. As considered with the NITS warfare, this is limited in part by the supplies that can be carried with the attacking forces. This impact grows less the more efficient the orbit-to-surface technology is - a localised NITS like the Star Trek transporter beam obviously makes resupply from orbit much easier than using any kind of shuttlecraft, however efficient that shuttlecraft might be.

One particular threat posed to troops landing using a shuttlecraft is that the journey from orbit to surface will take some time, during which they are relatively defenceless and missiles or other weaponry fired from the planet surface would be able to target it, as with missile defence shields that have been proposed by the US military in recent decades. This would require the ability to destroy those weapons from orbit, and/or the ability to land sufficiently far away from the target colony as to make the probability of being hit small enough that enough shuttles get through the defences.

Once troops are landed, then many of the tactical issues are the same as for a large-NITS war, in terms of defence. The key difference is that the supply lines for the enemy are cut once orbital superiority has been established by the attacking fleet. Since H colonies are likely to be close to self-sufficient, orbital siege is not a viable option, but the fact that the enemy cannot reliably send new forces onto the planet surface to join the battle means that the large-scale deployments of the large-NITS situation discussed before will not occur. In order to win, all the attackers need to do is transport enough troops and arms to the planet to defeat the defenders already there.

This covers what might happen once an attacking fleet reached the target colony. However, a problem faced by NSF armed forces that would not be faced by NITS armies is that between arriving in the solar system and attacking the colony, they have to travel from the outskirts of the solar system to the inhabited world or worlds.

Space is pretty big, even when we're talking about space within a solar system. However, for NSF economies to develop, travelling around a solar system has to take place fairly rapidly, and that means that detection of and response to an attacking force arriving in the environs of a solar system would be relatively quick as well. A defending colony will most probably be able to send for reinforcements before the fleet arrives, as long as a starship of their own side was present in the system to start with. While in peacetime that might be unlikely, it would appear to be an essential requirement of defence once war broke out. It will still take some time for reinforcements to arrive (how long would depend on the size of the empire and the top speed of the faster-than-light drive - the larger the empire, the closer in terms of travel time the nearest neighbouring system is likely to be). The objective for the defenders in the meantime will be to delay the attackers as much as possible, and to try to destroy as many of them as possible before they reach the target world.

Essentially, there are two approaches to this: the first is to engage the attackers as they travel from the outer solar system towards the target planet. The second is to engage them once they are in orbital range of either the planet or any moons it might have. The first costs more, but gives more opportunities for destroying the enemy or delaying them. The second means that planet-based weapons can be used to attack the enemy fleet, but equally the enemy fleet can use orbit-to-surface weapons against the colony if the aim is mainly to deny its use to the defending power. In practice, it seems likely that orbital weapons satellites would make sense anyway, automatically giving the second option some weight, while if there are any warships already in the system for the defending power, they would do best to attack the incoming fleet before it reached orbit. The orbital defences would need to be targeted at least partly towards the planet, to deter any attempt to land shuttles until the orbital defences have been destroyed by the attackers. The aim of the defenders is to use these resources to hold off the attackers until enough of their own warships can arrive to prevent the attacking fleet from capturing the colony. If this does occur, then at the last there is the threat of a scorched-earth policy by the attackers, who might launch a massive orbit-to-surface weapons strike to destroy the colony and deny its resources to the defending power in that way.

In essence, the battle will most likely be over if the attacking fleet manages to gain orbital superiority before the defending fleet arrives within firing range of the attackers.

If the colony falls before the defending fleet arrives, but the defending fleet arrives after that, then the roles are reversed: the defenders will be trying to recapture the colony (or destroy it to prevent the attackers using its resources), while the attacking fleet will be trying to destroy the new arrivals. The newly-arrived defending fleet will have one advantage: if they have come in answer to a call for help sent when the attacks came, then they will have a rough idea how many attackers there were and will have been able (if the resources exist within range) to send a larger force than the attackers had. The attackers, however, will have the option of sending their own report concerning the capture of the planet and asking for reinforcements to make sure they hold it - it may be that a tactical reserve would be sent a few days behind the initial assault team to provide that back-up and enable them to hold the colony if they should succeed in capturing it.

Eventually, because NSF takes significant time to move resources across the empire, one side or the other will run out of forces that are near enough to be sent to the system under attack in time to affect the outcome of the battle, or else the cost of sending further weapons and troops to the system outweighs the possible advantage of holding it. Again, this might result in a "scorched earth" policy, of destroying the colony before withdrawing, so as to deny its use to the enemy.

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We have seen that interstellar war on the basis of natural space flight transport will have several tactical problems for attackers, centring on how to maintain the usability of the objective while still taking it from the enemy. Battles in interplanetary space, and in orbital space are both likely, as well as "traditional" battles on hospitable planet surfaces, depending on the defenders' deployment in the system. Inhospitable planets or satellite colonies will most likely be targets for destruction, due to the difficulty in capturing them intact, but using this as a threat could be used to force the surrender of the colony if it is not defended well when attackers arrive.

In my next piece in this series, I will look at what a NSF warship might look like, and how space battles might be fought.