In the reference implementation of the VPSL system, the adaptive nut separates from the launch sled and spacecraft at the end of the forward acceleration section. While the sled and spacecraft continue to coast at full speed up the ramp, the pitch of the screws transitions from "variable and gradually increasing" through "constant" to "variable and rapidly decreasing". The adaptive nut adapts to this change by repositioning its grappler pads to the opposite sides of the screw flights. The "variable and rapidly decreasing" pitch of the screws decelerates the adaptive nut, bringing it to a stop near the downrange end of the ramp. Because the ramp is much shorter than the acceleration section, the adaptive nut must decelerate at approximately 820 m/s² (about 84 g) to stop before reaching the end of the ramp. Although this is a high acceleration for a payload, the adaptive nut is a purpose-built mechanical assembly engineered to tolerate such loads.

The current mass budget allocates 10,000 kg to the adaptive nut, 1,000 kg to the sled, and 24,940 kg to the fueled spacecraft. While the nut experiences a higher deceleration rate than its earlier acceleration, the total mass being decelerated is smaller.

The screws in the deceleration section are similar in construction to the screws in the acceleration section but incorporate a more rapid change in pitch to achieve the required braking rate. In the deceleration section, inside each screw, flywheels start out spinning more slowly than the screws. As the adaptive nut threads along the deceleration screws, its linear momentum is converted into rotational torque on the screw shafts, and that torque is transmitted through electromagnetic clutches to the flywheels, causing them to accelerate. In effect, the nut’s forward kinetic energy is absorbed as an increase in flywheel angular velocity, with the flywheels acting as temporary energy reservoirs during braking.

At the end of the ramp, the adaptive nut disengages from the guideway and is set aside, clearing the system for the next launch. Multiple adaptive nuts are employed when several spacecraft are to be launched in rapid succession. During pauses in launch operations, the adaptive nuts are reattached to the guideway and returned at low speed to the starting position in preparation for subsequent launches. Each adaptive nut descends the ramp under gravity and then coasts along the maglev guideway, with linear motors spaced at intervals of several kilometers providing propulsion assistance to maintain speed throughout the return journey.

Following each launch, electric motor-generators recover the flywheels’ stored rotational energy, converting it to electrical power while slowing them down for reuse. The recovered energy is then supplied to the motors in the acceleration section to re-spin-up those flywheels in preparation for the next launch cycle.