Trace the evolution of high-altitude flight from early 20th-century aeroplane altitude records to modern stratospheric and space exploration, highlighting the physiological challenges involved.

Flight above roughly 10 km demanded not merely stronger engines but artificial life support. From the inter-war altitude contests to today's orbital missions, the ceiling of human flight has been set less by machines than by the limits of human physiology.

Age of record-chasing (1920s)

• Post-WWI advances in aero-engine design triggered prestige-driven contests among France, the USA and Italy; Lt. John Macready reached about 40,800 feet by 1923 [2].
• In 1926 the French airman Callizo claimed a mark of over 7¾ miles near Paris in an oxygen-equipped Blériot-SPAD — the claim was later annulled for tampering with the barograph, an early lesson in record verification by certifying bodies such as the FAI, which still validates air-sport records [1].

From stratosphere to space

• Attention shifted from aeroplanes to sealed gondolas and balloons. Capt. Hawthorne C. Gray ascended to 42,470 feet in May 1927, but died of oxygen starvation on a repeat attempt that November — proof that unpressurised flight had reached its ceiling [3].
• Stratospheric flight is now routine science: NASA's Scientific Balloon Programme floats payloads at 36–42 km, providing low-cost access to near-space [4].
• Orbital flight is the present frontier — India's Gaganyaan will carry a three-member crew to a 400-km orbit [5].

Physiological challenges

• Hypoxia: above 12,000–15,000 ft, judgment, memory and coordination deteriorate, with tunnel vision setting in beyond 15,000 ft; supplemental oxygen is advised above 10,000 ft [6].
• Extreme cold near -50°C, and, higher still, ambient pressure so low that oxygen masks alone fail — mandating pressurised cabins and full-pressure suits.
• In orbit, microgravity and cosmic radiation add bone loss and long-term health risks.

The century-long ascent shows that each engineering leap has had to be matched by an advance in aerospace medicine. India's investment in astronaut training and life-support technology through Gaganyaan continues that tradition — extending human reach while keeping the human body, and verified scientific integrity, at the centre of the enterprise.