Technology
Development
Longshot is building kinetic launch to gradually accelerate a payload up to orbital launch speeds
Implementation
The current Longshot accelerator is located in Alameda, CA and consists of a kick stage, providing the initial impulse, followed by three boosters along the length of the 60-foot barrel. It is capable of accelerating payloads 6 inches in diameter up to Mach 4.2.
This technology demonstrator was built to:
- Measure the speed and location of the payload in the barrel
- Implement high speed gas injection
- Develop safe and rapid test operations
- Demonstrate building low cost hardware that meets challenging performance constraints.
Design
Longshot’s current prototype spread the acceleration of the projectile out over time. The speed is limited by the top speed of the gas, which is determined by the gas composition and temperature.
For room temperature nitrogen, this is a maximum of just over Mach 4, about 1/6th the speed needed for space launch.
By moving the system to the desert, Longshot can use hydrogen as the accelerant gas. By extending the length of the barrel to 500+ meters and adding more boosters, Longshot will be able to accelerate payloads of 100kg up to Mach 5+ at acceleration loads that your cell phone can survive, and at prices significantly lower than current rocket-based accelerator systems.
History
Kinetic launch has been used for decades to either extend the period of acceleration of a projectile, or attempt to put things in space.
The V3 was designed to send projectiles on a long-range trajectory.
The multiple injectors meant that the system could be made from inexpensive materials that were not designed to take high temperature or pressure, and the projectiles would experience relatively mild accelerations. It was never made fully operational.
HARP was a very large but traditional cannon designed to send projectiles into space.
It was made of high quality materials that could take the high temperatures and pressures required.
The single impulse meant that the projectiles experienced extremely high accelerations. It was commissioned in the 60's and fired a single projectile to 180 km altitude before the program was cancelled.
Longshot CEO Mike Grace built a multi-injection PVC cannon in his garage, that was eventually modified into a 20ft. long version.
The prototype fired foam projectiles at Mach 1.8, demonstrating the ability to accelerate projectiles with a multi-injection system with low hardware costs.
This laid the groundwork for the construction of Longshot's Oakland accelerator, and the future system in Nevada