Did Newton's cannonball predict the speed to orbit, and how close did rockets get?
Research question: Did Newton's cannonball idea predict how fast a cannonball would have to travel to keep falling around Earth without landing, and how close did early rocket designers get to that speed?
The records show that Newton's thought experiment predicted a projectile fired at the orbital speed for its altitude would keep circling Earth 4. One source gives a specific figure of about 8 km per second, or roughly 28,000 km per hour, for orbital freefall around the ISS 8. Early rockets fell far short of this: ordinary ones reached gas ejection velocities of only about 1,000 ft/sec 2, while Goddard's experimental chamber reached nearly 8,000 ft/sec 1, roughly a third of the ISS figure 18. Goddard's 1926 liquid-propellant rocket flew only 12.5 m high in 2.5 seconds, far below orbital speed 9. The facts do not show that early designers explicitly calculated their speeds against Newton's orbit prediction, and the newest fact is from 2024, about two years before October 2026 789.
Sources
"highest velocity being nearly 8000 ft.-sec., pro¬ duced by the chamber shown in Fig. 2, whereas"A Method of Reaching Extreme Altitudes (1920)
"the velocity of ejection of the gases, 1,000 ft/sec."A method of reaching extreme altitudes [manuscript], approximately 1919 (1919)
"For the moon the velocity is 1-5 miles per second, and for the planet Mars 3-0 miles per second."A Method of Reaching Extreme Altitudes (1920)
"If the speed is the orbital speed at that altitude, it will go on circling around the Earth along a fixed circular orbit"Newton's cannonball
"If the speed is very high, it will leave Earth in a parabolic (at exactly escape velocity) or hyperbolic trajectory."Newton's cannonball
"Newton's cannonball was a thought experiment Isaac Newton used to hypothesize that the force of gravity was universal, and it was the key force for planetary motion ."Newton's cannonball
"Newton postulated that, if fired fast enough, the cannonball would reach a state of continuous freefall around Earth, a state we have defined as orbit."ARCH 2001 - A Space Odyssey - The Architecture of Microgravity Environments (2024)
"This occurs when objects are moving at a speed of 28,000 km per hour (17,500 mph)"ARCH 2001 - A Space Odyssey - The Architecture of Microgravity Environments (2024)
"The rocket flew 12.5m high, 56m away, in 2.5 seconds, inaugurating a new era of rocket flight."ARCH 2001 - A Space Odyssey - The Architecture of Microgravity Environments (2024)