11/14/2023 - Written By Chris Quilty
Ever since Tsiolkovsky published the rocket equation in 1904, bold inventors and theorists have endeavored to break the equation. Balloons Horizontal launch. Space elevators. We get it. The engineering required for a satellite to survive three minutes on a high-G shaker table doesn’t come cheap. Horizontal launch from an aircraft at 35,000 feet enables a satellite to avoid 75% of the Earth’s atmosphere, while Zero 2 Infinity intends to launch from an altitude of 30 kilometers (above 99% of Earth’s atmosphere) using a balloon for primary assent.
Orbital Sciences tried and failed. The company’s Pegasus air-launched rocket conducted 48 missions over 32 years, but even the government’s largess (~80% of Pegasus missions) was insufficient to achieve commercial viability. Virgin Orbit followed the same fate, just quicker due to the Falcon 9 buzzsaw. Virgin Galactic, with its focus on human-rated spaceflight, is largely insulated from the competition that killed its wayward offspring. However, the company’s Unity spacecraft: (1) flies too infrequently, (2) carries too few passengers, and (3) has operating costs that are too high. For Virgin’s Delta vehicle to be any different, it will need to reverse these three problems and do so before the company drains its bank account. Virgin Galactic is forecasting the Delta spacecraft to generate a 12x revenue increase over Unity. That’s pretty impressive, but is it enough to overcome the curse of horizontal launch?
SOURCE: https://spacenews.com/virgin-galactic-to-halt-unity-suborbital-flights-by-mid-2024/