News

The Breakup of SpaceShipTwo Frame by Frame From the Tail Boom

By Doug Messier

Parabolic Arc

November 12, 2015

Filed under Mike Alsbury, NTSB, Pete Siebold, Scaled Composites, space tourism, space tourists, SpaceShipTwo, suborbital flights

Engine start on SpaceShipTwo. (Credit: Scaled Composites/NTSB)

Part 3.2 in a Series

The following sequence is extracted from a National Transportation Safety Board (NTSB) document about the loss of SpaceShipTwo last October. The images show the breakup of the vehicle from a camera on one of the tail booms. The premature unlocking of the feather mechanism resulted in aerodynamic pressures deploying the movable tail booms during powered ascent.

NTSB experts did the annotation on the photos and the narrative that accompanies the images. The sequence spans 3 seconds.

Figure 62 (Credit: Scaled Composites/NTSB)

Figure 62 is the last frame exported from the recording that shows the feather in a undeployed and nominal position. A vertical line was drawn at the intersection of the right boom’s leading edge and the contour of the upper fuselage structure to illustrate the feather’s relative position. In every frame prior to this, the feather position is nominal. By figure 62 and forward, the exported images show positive feather movement indicated by the incongruity between the vertical line and the relative position of the right boom’s leading edge and the contour of the fuselage.

Figure 63 (Credit: Scaled Composites/NTSB)

Figure 63 contains the first evidence indicating feather position movement. The vertical line from figure 62 was transposed onto figure 63. A slight change in relative position between the right boom leading edge and the upper contour of the fuselage was noted. Additionally, a region on the inner surface of the right boom covered in aluminized Kapton is observed having a slightly larger surface area indicating that the feather had slightly changed position. Slight feather movement was observed in frame 0330 (not shown) using the same techniques (Time 17:07:29.857) but was unable to be clearly presented in a graphics format.

Figure 64 (Credit: Scaled Composites/NTSB)

Figure 64 shows a portion of the right boom leading edge is visible to the left of the transposed vertical line applied from the previous figures. By this frame, movement of the feather is apparent when compared to figures 62 and 63.

Figure 65 (Credit: Scaled Composites/NTSB)

Figure 65 shows an increase in feather movement. The vehicle continues to pitch upward.

Figure 66 (Credit: Scaled Composites/NTSB)

Figure 66 is the last exported frame from the recording that was clear and did not contain video artifacts likely associated with the abrupt removal of power to the camera system. A significant increase in feather position is noted.

Figure 67a (Credit: Scaled Composites/NTSB)

Figure 67a shows the last frame in the series of exported images where the feather flap hinge line does not exhibit displacement. The feather flap hinge line in this image appears nominal.

Figure 67b (Credit: Scaled Composites/NTSB)

Figure 67b is the corresponding still frame exported from the boom camera hard drive containing high definition imagery.

Figure 68a (Credit: Scaled Composites/NTSB)

Figure 68a shows the first frame in the series of exported images where a displacement is exhibited along the feather flap hinge line. From this moment forward, the feather structure appears to become further displaced from the main structure of the vehicle.

Figure 68b (Credit: Scaled Composites/NTSB)

Figure 68b is the corresponding still frame exported from the boom camera hard drive containing high definition imagery. Figure 68b shows greater detail of the cracks forming on the outboard root fairings and the lightweight “taco” area. The high definition file also shows the Kapton foil failing in the upper left hand corner of the frame, the area near the leading the edge of the left boom structure.

Figure 69a (Credit: Scaled Composites/NTSB)

Figure 69a shows a field of view change apparent in the recorded images. The nose section is no longer visible. The change in field of view could possibly be attributed to the left boom structure being forced longitudinally outward, rotating inward, or a combination of both. Increased displacement is exhibited along the feather flap hinge line on the left side of the vehicle.

Figure 69b (Credit: Scaled Composites/NTSB)

Figure 69b is the corresponding still frame exported from the boom camera hard drive containing high definition imagery. The high definition file shows a portion of missing Kapton on the right boom structure and the continued failure of the upper feather flap skin and root fairings. Video artifacting has become present on the recovered high definition file.

Figure 70a (Credit: Scaled Composites/NTSB)

Figure 70a shows a further change in the camera’s field of view, only one window is visible near the main fuselage. Evidence of debris separation likely not attributed to video artifacting is near the center of the frame. Further separation between the wing trailing edge and the feather flap is visible.

Figure 70b (Credit: Scaled Composites/NTSB)

Figure 70b is the corresponding still frame exported from the boom camera hard drive containing high definition imagery. The high definition file shows the right feather flap structure completely failing. A skin panel from the bottom surface of the vehicle is seen removed from the structure and the left inboard upper root fairing structure is continuing to fail. Figure 70b is the last usable high definition file recovered from the boom camera hard drive. All subsequent recovered imagery contained heavy digital artifacting.

Figure 71 (Credit: Scaled Composites/NTSB)

Figure 71 shows the upper surface of the right mega strake becoming visible to the camera’s field of view. This indicates the right boom has begun to rotate inboard toward the centerline of the vehicle.

Figure 72 (Credit: Scaled Composites/NTSB)

Figure 72 shows an increase in the visibility of the upper surface of the right mega strake indicating further rotation of the right boom inboard toward the centerline of the vehicle. An open area is visible near the feather flap hinge line consistent with the color of the surrounding background near the left hand portion of the frame. Additionally, a crack has begun to propagate from the feather flap hinge line into the fuselage near the tail cone section of the vehicle.

Figure 73 (Credit: Scaled Composites/NTSB)

Figure 73 shows separation of the aft fuselage in the region of the tailcone. The crack along the feather flap hinge line has greatly increased in displacement. Background is visible between separated portions of the vehicle. The tailcone has begun to twist along the region of displacement, indicated by the “Virgin DNA” graphic becoming clearly misaligned (yellow line). Separation along the feather flap hinge line on the right side of the vehicle is also apparent, with background visible in the region of displacement. The right boom has mostly separated from the vehicle’s main structure and has continued to roll inboard with the upper surface of the right megastrake becoming more apparent to the camera’s field of view. The Virgin logo on the right side of the vehicle near the feather flap hinge line is attached to the right boom structure and separated from the vehicle.

Figure 74 (Credit: Scaled Composites/NTSB)

Figure 74 shows the camera has begun to power down and the recorded image is rapidly losing fidelity. The upper surface of the right mega strake is more apparent, indicating a continued roll inboard toward the center line of the vehicle. The “Virgin DNA” graphic on the upper portion of the main fuselage is in close view, indicating a significant change in displacement between the camera and the main fuselage.