Changes

While the drogue chute brings down the rocket quickly, the altimeter is still measuring the altitude of the rocket. When it descends to a pre-programmed height (which you control), it then triggers a second charge. This charge pushes out the main parachute (usually stored in the front part of the rocket). Since the rocket is now closer to the ground, the wind doesn't have the time to push it downrange too far. So it lands slowly, but much closer to the launch pad.

While the drogue chute brings down the rocket quickly, the altimeter is still measuring the altitude of the rocket. When it descends to a pre-programmed height (which you control), it then triggers a second charge. This charge pushes out the main parachute (usually stored in the front part of the rocket). Since the rocket is now closer to the ground, the wind doesn't have the time to push it downrange too far. So it lands slowly, but much closer to the launch pad.