We Will Destroy Your Planet (10 page)

There is a big difference between space superiority and air superiority within the Earth's atmosphere. Space superiority can be maintained with stationary vessels, and the ability to conduct orbital bombardments. Air superiority requires constant movement, either very quickly, with great agility, or in such a way to avoid detection. Air superiority means being able to control traffic in the atmosphere and use that control to exert force upon the surface and upon other atmospheric traffic.

Air superiority is a misleading subject for the tactical planners of an invasion of Earth, or any other planet. In particular, if you have a fleet of starships in orbit it may be tempting to assume that you have air superiority handled. After all, you came who knows how far, you can observe everything that happens in the atmosphere below, and you can target anything moving down there, can't you?

Well, not necessarily. For one thing, it all depends on what weapons technology you brought with you. If you only brought strategic missiles, or mass-drivers, or some form of artillery designed for engagements between capital ships, then you will have a problem. Depending on the ship(s) you have as strategic/tactical support, your weapons systems simply may not be able to hit a manoeuvrable aircraft below, for example. Strategic weaponry simply isn't suited to quick reactions and the flow of an aerial combat.

If you have no backup in orbit, you will also require air superiority for the strategic bombing component of your attack, if you have one. So, you are going to need to dip into the atmosphere in order to establish superiority there.

Strategic bombardment does not just mean dropping rocks from orbit, however effective that may be. Clearly you can assault surface targets with many forms of ordnance, be they bombs, missiles or meteors, and whether they be delivered from orbit, launched from surface installations, or delivered by aircraft. There are many practical reasons for the application of strategic bombardment – to destroy military or manufacturing infrastructure, prevent gathering of insurgent forces, deny areas to enemy forces, and so forth – but one thing it is
not
suitable for is reducing the population's will to resist.

Historically, the military forces of various native terrestrial nation-states have often used strategic bombardment for exactly this purpose, but, historically, it has never worked to that purpose. In every recorded instance, the survivors of the bombed population have in fact simply become more determined to resist.

Therefore, use your strategic weapons as you desire for the practical purposes mentioned above – or indeed simply to eliminate large numbers of the local populace – but if your intent is to reduce their will to resist, then you will be wasting your time using this method.

For both the interception of other aircraft and fast precision attacks on small ground targets, you will need a faster, more manoeuvrable type of craft. Machines suitable for one individual occupant are best, as they can be smaller, faster, and more agile, and carry a decent weapons load.

The weapons load will vary according to whether a craft is optimized for strategic bombing, tactical ground attack, or interception of other aircraft. Currently on Earth, most airborne combats take place at long range, with missiles launched from miles – sometimes even tens of miles – away. The requirement for manoeuvrability in human-built aircraft, therefore, has more to do with the need to avoid inbound missiles than to follow a target around for a close-up attack. Depending on the nature of the weapons you mount on your atmospheric craft, this may not be the case for you.

If you fit your interceptors with light-based energy weapons, the beam should reach the target pretty much instantaneously, considering the distances involved, and so agility will be less of a requirement. If you fit projectile or particle weapons that require visible time to reach the target, or are affected by wind, gravity, or the scattering properties of moisture in the atmosphere, then you will need both speed and agility in order to get closer to your target for a higher probability of a kill.

You will also need greater agility if you intend to either rely on using part of your aeroform as a weapon – for example using a strengthened wing leading-edge as a blade to sever parts of other aircraft – or if you intend to operate at low altitudes where there is a need to avoid buildings, foliage, or geological structures.

Note that human-built aircraft tend to be relatively lightweight and therefore fragile. It does not take a large warhead or a large amount of energy impact to damage one beyond its ability to remain flying. Since your aim should be to eliminate as many enemy craft as possible to attain victory in the skies, there is no need for overkill. Calculate your weapon load to give you the best chance to hit more enemies, rather than fewer chances to do more damage to one. Also bear in mind that, with the object of victory in mind, it is the enemy aircraft you must prioritize, not the pilot (if there is one), so it is not a problem if the pilot survives the destruction of his or her machine.

You may find that you can use the same vehicles as close support craft both in and out of the planetary atmosphere, but this may present difficulties, depending on your systems of motive power and steering.

In the atmosphere, your best mode of steering a fast atmospheric vehicle will be through the use of ailerons and control surfaces built into a lifting body. In other words, you will need a vehicle design capable of being held aloft by the pressure of the air passing under it, and which can be steered by altering the surfaces in such a way as to change how much lift, or in what direction, the airflow gives you.

This is very different from in vacuum, where there is no pressure to steer against, and space-superiority fighters need manoeuvring thrusters and reaction control units for changes of orientation and direction. Your atmospheric craft will require aerofoils and rudders, and will not be able to simply spin around on the spot.

Let's get the disappointing bit out of the way first; saucers are not a good shape for this type of craft, if you are building aircraft locally. Unless you have a solid, stable, antigravity propulsion for saucers, then leave them at home, as they will basically be suicide machines in the atmosphere, prone to flipping, tumbling, and crashing. However, if you have stable antigravity and do bring along saucers for atmospheric combat, you will find they give a psychological advantage, at least before your attack becomes widely known, as humans will find it difficult to believe your saucers are actually flying in their airspace, and be reluctant to report an engagement for fear of being considered to be hallucinating.

For high-speed aircraft, you will be better off with a delta shape, with a slim point at the front. The wingspan should be less than the overall nose-to-tail length of the craft, to reduce air resistance. For manoeuvrability of ground attack aircraft, and those operating at lower altitudes as close-support in combat areas, try larger wing areas, with a wingspan wider than the length of the craft. This will give greater stability at slow speeds, and a tighter turning circle.

You will also need a tail with a rudder for steering to one side or the other, and movable flaps on the trailing edges of the wings, for climbing, diving, and tilting to the side.

You can also use rotary-wing aircraft, or what the humans call helicopters. These use a horizontal set of tilted blades spinning at high speed to achieve lift, though most such craft will require a vertically-aligned set of blades at the end of a boom in order to maintain stability and not spin. Most such terrestrial craft have their main rotor set mounted about the fuselage, though there are variations.

If you really love your saucers, it
is
possible to use two contra-rotating sets of rotors at the centre of a saucer-shaped hull, though this will not have great speed or agility. All the same, the most important factor in your aerial adventures in Earth's atmosphere is the ability to shoot down human aircraft without crashing.

Earth's news media is replete with tales of travellers from space who are capable of traversing the infinite gulfs with their magical and near-godlike technology, but who are apparently incapable of noticing where they are in relation to the actual ground. Do not make this mistake. Do not allow the Earth natives to capture and reverse-engineer your vehicles, and to turn their crash sites into tourist attractions. If nothing else, this is embarrassing when you are trying to build a reputation as conquerors feared and respected across the galaxy.

It's even more embarrassing if your pilots are captured, interrogated, or dissected. Note, though, that you do not actually need to have your aerial vehicles carry a pilot. Even on Earth, there is an increasing use of remotely-piloted vehicles and drones, which can be used for reconnaissance and close combat support without endangering an occupant. Since you, as new arrivals, will likely have less access to replacements for lost forces, this is a wise approach to take.

A flying machine can be replaced quite easily, as quickly as the components can be manufactured and assembled, but a pilot's experience cannot be so easily replaced.

In total, 70% of the Earth's surface is water, and so, while you are living, working, hunting, and fighting on the surface of the planet, you will have to be able to deal with going into areas covered in water. Obviously this will not be a problem for aquatic species, who will only need to concern themselves with the issues of salinity – whether a specific body of water is salt water or freshwater – and the Earth's own aquatic life forms being either food or predators.

If you are a land-adapted species like humanity, or an avian species, you will obviously require, at the very least, adaptation for immersion in water. It's reasonable to assume that if you're capable of having built starships to come to Earth from your homeworld, then you're also capable of building both aerial and submersible vehicles. If you can make spacesuits to provide you with a breathable atmosphere or protect against low pressures, you can make suits to protect yourselves in water.

Do not, however, be tempted to think that because you have already demonstrated the ability to build a pressurized vehicle for travelling through the near-vacuum of space, that you can simply use the same constructions to travel underwater, no matter how cool SHADO's Skydiver combo from
UFO
or the saucer-shaped flying sub from
Land of the Giants
look when you view those transmissions. Trying to pull off the combination is probably unwise, though not necessarily impossible.

The structure of a mechanical construct built to withstand the absence of pressure is of necessity very different to the structure of something designed to withstand increasing external pressures and the load bearing of immense tonnage of water. At base, a vehicle designed as a submersible will have to be built with a greater attention given to internal supports and bulkheads more evenly spread throughout the design, as opposed to being designed to withstand g-forces at launch, and then zero pressure outside thereafter.

The deepest underwater point on the Earth's surface is 36,200 feet down. That means the pressure there will be 1,097 bar, 1,097 times the pressure of the atmosphere at surface level. The average depth of the Earth's oceans is around 14,000 feet, or 2.65 miles, with a pressure of 424.24 times the atmospheric pressure at sea level. This means any submersible vehicle must be designed and built to protect its interior from that level of external pressures.

Since the mechanical engineering requirements are very different, it would make far more sense to design and use separate vehicles for these environments. It would not be impossible to build one that could be used in the full range of pressures, but the cost-effectiveness in resources would be far less.

You will not need antigravity or the like to power submersible vehicles, or to allow them to ascend and descend. Flooding buoyancy tanks with water will allow descent, and flushing them with air will enable ascent. A submersible or surface boat can easily be powered by any form of storage batteries (so long as they are of the right scale) or power generator, nuclear or otherwise. On the surface, sails are still effective, and used across the globe. This is not a fast or highly technological means of propulsion, but excellent for silent movement and energy efficiency. Under power, a simple screw propeller, or multiples thereof, is still traditional both on surface and submersible vehicles. Propellers cause turbulence in the water, however, called cavitation (it leaves brief cavities, or holes, in the water), and because sound waves propagate even more effectively in the density of water than in air, this makes vessels detectable. A good solution, therefore, is to use some kind of hydrodynamic drive, drawing water in at the front of the engine, putting it under pressure, and squirting it out the rear, as per a jet or rocket engine. As well as being stealthier, this also makes for a smoother ride, and the relative lack of moving parts means there's less chance of catastrophic mechanical failure.