Black Knight - BK17

BK17 was another two-stage vehicle but with a lighter low-drag eroding head to give higher re-entry speed. The first stage performance was very good. The kerosene level sensor and H,T.P. probes worked well and propellent usage in flight was determined. Visual observation and camera records of re-entry were confusing but it soon became clear that the second stage had not functioned correctly. The head and tape recorder were recovered. Subsequent analysis of head tape record and body telemetry indicated that second stage separation occurred at re-entry and not at the end of first stage burning. It was possible to deduce from the records that the failure of second stage separation at first stage burn-out was due to failure of one of the two explosive bolts. (In subsequent vehicles explosive bolts and associated circuits were duplicated.) Subsequently at re-entry the second stage was torn off, followed by second stage burning. Body telemetry was satisfactory until re-entry: good records were obtained of motor pressures, control data and propellant levels. After burn-out telemetry channel change-over switch No.1 operated so electron temperature was recorded and the "Faraday" propagation experiment was successful but, because switch No.2 failed to operate, the galactic radio noise was not recorded.

In subsequent vehicles change-over of telemetry channels was time-operated and independent of second stage operation. The head was separated from the second stage but remained in the separation bay of the body until at re-entry physical separation of body, second stage and head took place.

The tape of the recorder in the head ran out before re-entry. In subsequent heads, the speeds of the tape in the tape recorder was reduced so as to run for a longer period and ensure recording re-entry.

Number Stages Date local
time Empty
wt [lbs] HTP
[lbs] Kerosene
[lbs} All up
wt [lbs] Burn-out
time [s] Apogee
miles

17 1 7 6 61 20.50 2 015 9 862 1 358 13 235 144.5 362