Hypersonic flight

Hypersonic Flight: Pioneering Speed Beyond Mach 5
Hypersonic flight refers to the act of flying through the Earth’s atmosphere at speeds exceeding Mach 5, typically below altitudes of around 90 kilometers. At these velocities, air molecules begin to dissociate, and substantial heat is generated due to aerodynamic forces. In fact, speeds surpassing Mach 25 have been attained beneath the thermosphere as of 2020, although a citation is required for this claim.

Hypersonic vehicles possess the capability to navigate through the atmosphere along non-parabolic trajectories. However, their operation necessitates effective management of the intense aerodynamic heating they encounter, as illustrated by the blackened tip of a reentry vehicle in the accompanying image. This phenomenon is akin to the aerodynamic heating experienced by iron meteorites during atmospheric entry.

History of Hypersonic Flight
The inaugural instance of hypersonic flight was achieved by the two-stage Bumper rocket, which combined a V-2 first stage with a WAC Corporal second stage. In February 1949, this rocket soared to a remarkable speed of 8,290 km/h (5,150 mph), equivalent to approximately Mach 6.7, at White Sands. Regrettably, the vehicle succumbed to the intense heat of atmospheric re-entry, leaving behind only charred remnants.

The era of human hypersonic travel dawned in April 1961 when Russian Major Yuri Gagarin embarked on the world’s premier piloted orbital flight, surpassing hypersonic speeds. Shortly thereafter, in May 1961, Alan Shepard became the first American and the second individual to achieve hypersonic flight, as his capsule re-entered the atmosphere at speeds exceeding Mach 5 at the conclusion of his suborbital voyage over the Atlantic Ocean.

November 1961 marked another milestone when Air Force Major Robert White piloted the X-15 research aircraft at velocities surpassing Mach 6. Notably, on 3 October 1967, an X-15 in California attained a speed of Mach 6.7.

Extensive research addressed the re-entry challenges of space vehicles, culminating in notable achievements such as the NASA X-43A, which flew under scramjet power for 10 seconds before gliding for 10 minutes on its final flight in 2004. Subsequent advancements included the Boeing X-51 Waverider, which flew under scramjet power for 210 seconds in 2013, ultimately reaching Mach 5.1 during its fourth test flight. The hypersonic realm has emerged as a focal point for 21st-century exploration and strategic competition among nations such as the United States, India, Russia, and China.

Future of Hypersonic Technology
The continuous development in hypersonic technology holds significant implications for both civilian and military applications. As nations strive to achieve superior speed and maneuverability, hypersonic flight remains a critical area of research and innovation.