Missiles And The Speed Of Light: Is It Possible?

The speed of missiles is a crucial aspect of military strategy, with significant implications for global security, international relations, and arms control. Missiles can achieve very high speeds, with intercontinental ballistic missiles (ICBMs) capable of reaching approximately 24,000 kilometres per hour (15,000 miles per hour) during their mid-course phase. This speed is remarkable, yet it pales in comparison to the speed of light, which is a staggering 1,079,252,848.8 kilometres per hour. So, can missiles ever reach the speed of light?

Hypersonic missiles can travel at 5x the speed of sound

Hypersonic missiles are defined as those capable of travelling at speeds above Mach 5, or five times the speed of sound. There are several types of hypersonic weapons, including hypersonic glide vehicles (HGVs), hypersonic cruise missiles, and hypersonic aircraft. These missiles are distinct from ballistic missiles, which follow a simple trajectory and are unpowered for most of their flight. Hypersonic weapons, on the other hand, use aerodynamic lift to manoeuvre under guided flight within the atmosphere.

Hypersonic weapons can be powered by strong rockets with aerodynamic designs, allowing them to accelerate incredibly fast and achieve hypersonic speeds. The design and engineering of these weapons are complex, as they need to withstand extreme heat generated by compressed air at the leading edge. The development of hypersonic weapons has been an area of active research and military interest, with various countries investing in their development and deployment.

One example of a hypersonic missile is the Russian Avangard, which was unveiled during the 2022 Russian invasion of Ukraine. Russia touted these missiles as capable of overcoming any foreign missile defence systems. Another example is the DARPA Hypersonic Air-breathing Weapon Concept (HAWC), which successfully achieved a flight speed greater than Mach 5.

While hypersonic missiles can achieve remarkable speeds, they are still far from reaching the speed of light. The speed of light is considered a fundamental physical limit, and reaching it would require an infinite amount of energy due to the mass of the object. Hypersonic missiles, even with powerful rockets, cannot come close to attaining light speed due to the sheer amount of fuel that would be required.

In conclusion, hypersonic missiles travelling at 5x the speed of sound represent a significant advancement in military technology, but they are still bound by physical limitations that prevent them from approaching the speed of light.

Ballistic missiles can reach 15,000 mph

Ballistic missiles are a type of missile that uses projectile motion to deliver warheads to a target. They are distinct from cruise missiles, which are aerodynamically guided in powered flight and therefore restricted to the Earth's atmosphere. Ballistic missiles, on the other hand, are often launched into high sub-orbital spaceflight, especially intercontinental missiles, which can reach altitudes of about 4,500 kilometres (2,800 miles).

The trajectory of a ballistic missile can be divided into three parts: the boost phase, the mid-course phase, and the terminal phase. The boost phase is the only powered flight portion, lasting from a few tenths of a second to several minutes. The mid-course phase is the longest, during which the missile enters free flight and can travel at speeds of up to 7.5 to 10 kilometres per second (4 to 5 nautical miles per second). The terminal phase begins when the missile re-enters the Earth's atmosphere and is influenced by atmospheric drag, which impacts its landing.

During the terminal phase, intercontinental ballistic missiles (ICBMs) can re-enter the Earth's atmosphere at very high velocities, reaching speeds of 6–8 kilometres per second (22,000–29,000 km/h; 13,000–18,000 mph). This speed range includes velocities of 15,000 mph, and so it is indeed possible for ballistic missiles to reach this speed. However, it is important to note that this speed range is specific to ICBMs, which have a range of over 5,500 kilometres (3,400 miles).

While ballistic missiles can reach incredible speeds, they are far from reaching the speed of light. To put it into perspective, the speed of light is approximately 299,792,458 metres per second, which is incredibly faster than the top speeds that any human-made object, like a ballistic missile, has ever achieved.

ICBMs are intercontinental ballistic missiles

An intercontinental ballistic missile (ICBM) is a ballistic missile with a minimum range of 5,500 kilometres (3,400 miles) or 5,600 kilometres (3,500 miles). They are designed to deliver nuclear weapons, although conventional, chemical, and biological weapons can also be delivered with varying effectiveness. ICBMs are differentiated from other ballistic missiles by their greater range and speed.

ICBMs are primarily land-based, although they can also be submarine-launched. They are powered only during brief periods, with most of the flight being unpowered. They are launched into a high sub-orbital spaceflight, and can travel in space indefinitely in the case of fractional-orbital capable systems. ICBMs can be deployed from multiple platforms, including missile silos, submarines, heavy trucks, and mobile launchers on rails.

ICBMs have three phases of flight: the boost phase, the mid-course phase, and the re-entry or terminal phase. The boost phase can last from a few tenths of a second to several minutes, depending on the number of rocket stages. The mid-course phase is the longest, where the missile enters free flight and can travel in space for thousands of kilometres. The re-entry or terminal phase begins when the missile re-enters the Earth's atmosphere, where it is influenced by gravity and aerodynamic drag.

ICBMs are equipped with multiple independently targetable reentry vehicles (MIRVs), allowing a single missile to carry several warheads that can strike different targets. Modern ICBMs tend to be smaller than their predecessors due to increased accuracy and smaller, lighter warheads. They also use solid fuels, making them less useful as orbital launch vehicles.

Cruise missiles are restricted to the atmosphere

Cruise missiles are distinct from ballistic missiles, which are a type of missile that uses projectile motion to deliver warheads to a target. Ballistic missiles are powered only during brief periods, and most of their flight is unpowered. Short-range ballistic missiles typically stay within the Earth's atmosphere, while most larger missiles travel outside the atmosphere.

Cruise missiles can be categorised by payload/warhead size, speed, range, and launch platform. They can be fitted with a variety of navigation systems and can carry either a conventional or a nuclear warhead. They are among the most expensive of single-use weapons, with each missile costing up to several million dollars.

The most common mission for cruise missiles is to attack high-value targets such as ships, command bunkers, bridges, and dams. Modern guidance systems allow for accurate attacks.

Hypersonic missiles are harder to detect

Hypersonic missiles are a type of weapon that travels at Mach 5 or faster—that is, at least 760 miles per hour at sea level. They are highly maneuverable, even in flight, and fly at lower altitudes than other missiles, making them difficult to detect and intercept.

Hypersonic missiles are designed to be too agile for traditional missile defence systems to detect in time. They do not follow a predetermined trajectory, and their high speed makes them harder to detect and interpret. Their low-altitude trajectories mean that satellite imaging is critical for early detection and ongoing tracking.

The high speed of hypersonic missiles also puts radars at a disadvantage when it comes to tracking and detection. To detect these missiles, radars need to be set up to track fast-moving objects. Without this capability, the signals from the hypersonic missiles won't be shown on the same track, and they will become impossible to track over time.

However, there are ways to counter hypersonic missiles. One method is to use higher frequencies to increase a radar's resolution, making it easier to detect smaller, fast-moving objects. Another approach is to use multiple radar systems, each focusing on a different aspect of the missile and acting on different frequencies.

In addition to radar technology, other countermeasures against hypersonic missiles are being developed. These include high-power lasers, microwave weapons, railguns, hypersonic interceptors, and cyberattacks to disrupt critical subsystems.

While hypersonic missiles pose significant challenges in detection and interception, ongoing research and advancements in technology aim to address these challenges and develop effective countermeasures.

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