Implanted boundary layer trip

Claim 1

A re-entry nose cone comprising a first and a second element; said first element being composed of a first carbon-carbon composite ablative material having a recess in the forwardmost portion; and said second element including a pair of components, one of the components of said pair of components being in the form of an implant positioned in said recess and being composed of a second carbon-carbon composite ablative material characterized by having a different density than that charactrerized by said first ablative material, and a surface roughness greater than that of said first ablative material, the other component of said pair of components forming a forward cap section for said implant and being composed of a third carbon-carbon composite ablative material characterized by having a density and surface roughness similar to that characterized by said first ablative material; whereby said nose cone exhibits a symmetrical erosion profile during its re-entry regime.

Claim 5

A method of controlling the ablation symmetry of a re-entry vehicle nose cone during its re-entry regime which comprises the steps of (A) providing a nose cone composed of a first carbon-carbon composite ablative material; (B) machining a recessed portion of predetermined configuration into the leading surface of said nose cone; (C) implanting a second carbon-carbon composite material into said recessed portion, said second ablative material characterized by having a different density, and greater surface roughness, than that characterizing said first ablative material, and (D) forming a forward cap section over said implant said cap section composed of a third carbon-carbon composite material characterized by having a density and surface roughness similar to that characterized by said first ablative material such that when said implanted second ablative material is exposed to a re-entry environment, its difference in surface roughness will uniformily trip the nose cone boundary layer thereby allowing the transition forward progression of said nose cone to proceed symmetrically and exhibit a symmetrical erosion profile during its re-entry regime.

Claim 6

A method of controlling the ablation symmetry of a re-entry vehicle nose cone during its re-entry regime which comprises the steps of (A) providing a nose cone composed of a first carbon-carbon composite ablative material; (B) machining a recessed portion of predetermined configuration into the leading surface of said nose cone; (C) implanting a second carbon-carbon composite material into said recessed portion, said second ablative material characterized by having a different density, and greater surface roughness, than that characterizing said first ablative material, and (D) forming a forward cap section over said implant said cap section composed of a third carbon-carbon composite material characterized by having a density and surface roughness similar to that characterized by said first ablative material such that when said implanted second ablative material is exposed to a re-entry environment, its difference in surface roughness will uniformily trip the nose cone boundary layer thereby allowing the transition forward progression of said nose cone to proceed symmetrically and exhibit a symmetrical erosion profile during its re-entry regime.