The Slipspace COM Launcher is an experimental piece of technology recently invented by the UNSC.
a COM probe launched by an underground gauss accelerator and then a Shaw-Fujikawa Slipspace Drive creates a slipspace rent in high orbit that the COM probe goes through slipspace like a "bullet" on an ultraprecise trajectory. It rips through the laws of known human physics, and drops back into normal space at some very distant coordinates. The probe actually navigates through slipspace, and traverses as far and as fast as any UNSC ship.
The technology would revolutionize long-distance communication. Far faster than conventional radio communication, if each ship were outfitted with such a device, messages could be delivered without requiring a ship to travel through space to manually give the message, especially when the ship is further delayed by the Cole Protocol.
Unfortunately, the cost to build a Shaw-Fujikawa ultraprecise low-mass launcher is comperable to a fleet of ships. Therefore, there are only three known launchers. One on Earth, one on Reach, and a secret one on Onyx, though the Onyx and Reach launchers were likely destoryed in The Battle of Reach and The Battle of Onyx, respectively.