For decades, lead bricks and concrete rings sufficed for test flights. But as the industry pivoted to (think SpaceX’s Transporter missions or Rocket Lab’s dedicated smallsat flights), a new problem emerged: variable mass.
The ingot does not deploy. It does not phone home. It becomes debris—a silent, 500-kilo brick now in a slightly lower parking orbit than the satellites it just supported. This is where the story gets controversial. launch ingot
Environmentalists are beginning to push back. “Each ingot has the kinetic energy of a freight train at orbital velocity,” says Dr. Liam O’Rourke, an orbital debris researcher at MIT. “We are intentionally placing dense, un-trackable bricks in high-traffic lanes. One collision with a Starlink satellite and the shrapnel cloud takes out a hundred more.” For decades, lead bricks and concrete rings sufficed
A single Falcon 9 rideshare mission might drop 10 to 15 launch ingots into Low Earth Orbit (LEO). While they are tracked by the 18th Space Defense Squadron, they are considered “passive disposable objects.” It does not phone home
As the rocket fuels, the ingot is doing its only job: being heavy. It pushes the center of gravity aft, reducing bending loads on the interstage.
This is the ingot’s moment of sacrifice. The upper stage performs a “ballast jettison” burn. Explosive bolts fire. Pneumatic pushers shove the ingot away from the stack at 1.5 meters per second.
The ingot is mounted to the top of the kick stage or the center of the rideshare stack. Engineers perform a “mass moment of inertia” (MMI) test, spinning the stack to ensure the simulated weight matches the flight software.