Analysis and Interpretation of the Delta 180 Collision Experiment in Space

Abstract

In a landmark experiment in 1986, the payload of a Delta 180 launch vehicle was made to collide with its second stage rocket. The collision produced two separate debris clouds without any significant center-of-mass cloud. The inclination and plane change angle distributions of the fragments in the two clouds exhibited Gaussian patterns, with the payload cloud having a considerably greater dispersion than the rocket cloud. Several fragments strewn between the two clouds showed some momentum transfer and hence originated from the contact area. The centers of the two clouds moved away from each other in apparent compliance with momentum conservation. The three orthogonal components of the velocity perturbations received by the fragments are calculated and the angular distributions of the fragments obtained. The total velocity perturbations could be fitted with a Maxwellian distribution whereas its components generally followed Gaussian trends. Fragments from the contact areas, including those thrown into high period orbits, generally fell outside these envelopes. A vast majority of the fragments from both clouds received velocity perturbations below the horizontal plane, thus indicating a loss of translational kinetic energy due to the fragmentation. Three preferred directions in the fragment spread in the horizontal plane suggest that the payload hit the rocket body at an angle from behind.