DESIGN:
The nose cone for the Orion vehicle is an 11 degree conical fiberglass nose cone with a machined leaded steel nose tip. This nose cone shape is optimized for supersonic flight, with a radious steel nose tip to provide a bow shock wave for less pressure drag and heat build up on the nose tip during flight. To dissipate the heat buildup on the nose cone during flight, it was coated with ablative coating.

CONSTRUCTION:
The nose was first turned from wood on a lath by Alaska Tool Company in Fairbanks, Alaska, to provide a plug for molding the fiberglass nose cone. A fiberglass female mold for the male nose cone plug was fabricated using materials from Fibre Glast. The nose cone was laid up by hand using epoxy resin laminated with 12 layers of 10 ounce Fibre Glast fiberlass cloth. The epoxy resin was then cured under vacum bagging to eliminate voids, and provide uniform adhesion of the epoxy resin to the layers of fiberglass cloth.

 

Testing and Analysis

THERMAL ANALYSIS:
Predicted flight performance estimated a nose tip stagnation temperature and pressure were projected for an Apache rocket motor. This nose cone and payload flew on a NASA supplied Orion motor, which provides higher performance, resulting in higher nose tip stagnation temperature and pressure. The short time line of approximately 2 months from NASA notification of Orion mission 30.044 UP to launch at Poker Flat didn't allow for a new nose cone thermal analysis to be completed prior to launch. Upon consultation with NASA/Wallops, the ablative coating listed in the specifications below was adopted.

SPECIFICATIONS:

 Length:
                              44 inches
 Weight:
                              6.0 pounds
 Nose Tip
                              1.5 inch length leaded steel
 Color:
                              Napa engine orange spray paint
 Ablative Coating:
                              Dow Corning 3145 RTV (MIL-46-146) clear rubber silicon adhesive/sealant, thinned out and brushed on with Naptha solvent.

FINISHING:
The completed nose cone was wet sanded to provide a smooth finish for priming and painting. The nose cone was painted using a base coat of Krylon white primer spray paint, and finished with a top coat of Napa engine orange spray paint. The clear rubber silicon ablative coating was thinned out with Naptha solvent and brushed onto the nose cone in several coats. Each coat was allowed to air dry prior to application of the next coat.

FLIGHT DATA:
Flight telemetry data for the nose tip stagnation temperature was received during flight. However, this data wasn't properly calibrated, so the data couldn't be used, and no flight data for nose tip temperature is available.