VALT is a vertically oriented catapult for launching model rockets.
It acts as a reusable first stage that never leaves the ground.
The purpose of VALT is to demonstrate the concept of using a ground accelerator to launch a rocket.
The advantage of VALT is that it reduces the amount of propellant that a rocket needs to carry to achieve orbit.
Reducing the propellant allows the rocket to carry a larger payload.
Some of this extra payload capacity can also be used to make the rocket reusable.
Increasing payload capacity and making the rocket reusable are the two key ingredients that are needed to make affordable airliner like operations to Earth orbit possible.