Green Launch is developing a device to launch objects into orbit at supersonic speeds using only a mixture of hydrogen and other gases.
Dr. John W. Hunter, CEO and Chief Research Officer of Green Launch, directed the Super High Altitude Research Project (SHARP) at Lawrence Livermore National Laboratory 30 years ago, leading to the development of the world’s largest and most powerful “hydrogen pulse launch device”.
Small-scale prototype of the hydrogen pulse launch device developed by Green Launch. (Photo: Green Launch)
The device is a long tube filled with hydrogen, helium, and oxygen, with the projectile positioned at the front. When this cannon fires, the gases expand rapidly, providing the projectile with a tremendous thrust from behind. The SHARP program developed and tested a 122-meter pulse launch device in 1992, breaking all energy and speed launch records, propelling various payloads (including a supersonic straight jet engine) at speeds of up to Mach 9 (11,113 km/h).
According to Eric Robinson, the Business Development Director at Green Launch, this method can scale better than circular accelerators like the SpinLaunch system. “The record for hydrogen propellant projectiles is 11.2 km/s. We plan to limit launch speeds to 6 km/s to enhance reusability and prevent wear and tear,” Robinson stated. Similar to the SpinLaunch system, the projectile from Green Launch’s device requires a small rocket to provide the final acceleration and achieve the correct trajectory. However, due to the hydrogen cannon launching the projectile at such high speeds, this rocket needs to be significantly smaller and lighter.
Green Launch estimates that the acceleration force will peak at 30,000 G. The company conducted a simple test to determine whether the electronics could withstand that force. They concluded that the acceleration would not affect the electronic components. Green Launch stated that launch costs would be minimal, only 1/10th of current rocket prices. By not using a rocket propulsion system in the initial phase, Green Launch’s system saves a significant amount of fuel and produces no emissions. Additionally, customers can mitigate risks with multiple launches instead of losing an entire satellite cluster in a single rocket explosion.
The hydrogen cannon can operate every 60 to 90 minutes, launching payloads into the atmosphere at supersonic speeds. The payload can reach low Earth orbit at altitudes of 300 to 1,000 km in less than two hours.
The company has constructed a 16.5-meter launch tube to demonstrate the concept. They successfully launched a payload into the stratosphere at speeds exceeding 3,705 km/h. By the end of this year, they aim to increase the speed sufficiently for the payload to travel beyond the Kármán line, which is 100 km above the Earth’s surface.
