Each flight model of Blue Streak was
numbered F1, F2, F3, and so on. The first
three launches – F1, F2 and F3 – were to be
just of Blue Streak itself, with a dummy
Figure 71. The Perigee Apogee nosecone weighted to simulate a payload. System, or PAS.
F4 and F5 had all dummy upper stages; F6/1 and F6/2 had live first and second stages; from F7 onwards all stages were live.
F1 reached Australia on 18 January 1964. It was set up in the launch gantry, and was static fired (that is, the tanks filled and the engines ignited, but the vehicle remained tethered to the ground and not released) on 30 April. The weather caused delays to the launch throughout May, and after other delays, the launch date was set for Friday, 5 June.
A report prepared by HGR Robinson of RAE states:
The vehicle was successfully launched at 9.11 a. m. after an extremely smooth and efficient final count down, both as regards vehicle and range… The vehicle lifted off
and programmed downrange according to plan, its flight path and walking impact point following closely to nominal. At about 130 seconds, however, telemetry records indicated the commencement of incipient instability. This became marked at 140 seconds, developing into an uncontrolled corkscrew at 145 seconds. At 147.5 seconds the engine ceased thrusting, some six seconds before the planned time for engine cut. The termination of powered flight has been diagnosed as arising from fuel starvation caused by the manoeuvres of the vehicle during its final period of instability.3
The problem lay in what was called ‘fuel sloshing’ – that is, the vibrations of the vehicle caused the remaining fuel in the tanks to slosh from side to side. As the ‘slosh’ built up, the control system was unable to cope, and the vehicle corkscrewed then tumbled. It was not a difficult problem to solve – the control system could be adapted to cope, and in any case, the vibrations would be different when the upper stages were added. Figure 72 shows three frames from the film of the flight showing the last few seconds.
Velocity at engine cut: Height at engine cut: Impact range:
(n. m. = nautical miles)
F2 and F3
Repeats of F1, F2 was launched on 20 October 1964 and F3 on 22 March 1965. Both flights were extremely successful, meeting all objectives.
Modification of the autopilot reduced the sloshing on F2 to a low and stable value; additional anti-sloshing baffles were installed in the liquid oxygen tank for F3.
This was a simulation of the complete vehicle, but with dummy upper stages, and the first launch to have the motors uprated to the full 150,000 lb thrust. F4 was launched on 24 May 1966 with a planned first stage boost duration of about 144.3 seconds and with the cut-off was to have been by exhaustion of the liquid oxygen. The flight was terminated after 135 seconds by the Range Safety Officer when it appeared that the vehicle was straying outside the range boundaries. This was a somewhat controversial decision, particularly when it was found that the vehicle had been inside limits; the range officer had acted on false tracking data caused by large cross-polarisation of the tracking transponder signal.
F5 was a repeat of F4, and was launched on 15 Nov 1966. The flight was a success.
Launched on 4 August 1967, the first and second stages were live, with a dummy third stage and satellite. The first stage performance was as planned, but the explosive bolts of the first/second stage separation system fired prematurely and the second stage failed to ignite. This was thought to be caused by an electrical fault which caused the second stage electronic sequencer to be reset. This meant the command to open the main valves was not given and the motors did not fire even though the main tanks had been pressurised by the gas generator.4
This was a repeat of F6/1, launched on 5 December 1967. Again, the first stage performance was as planned, but this time the first and second stages failed to separate.
The RAE report on F7 was as follows:
This vehicle was launched on the 30th November, 1968 … The most important defect during the trial was the complete failure of the 3rd stage immediately after separation from the 2nd stage. Final assessment has been unable to establish the cause of the failure but it has highlighted three areas which may have been either singularly or in combination responsible for the failure. These are firstly the pressurisation pipes which were of rigid construction. These may have fractured and for F8 a flexible element is included. Secondly, unscheduled operation of the break up system due to spikes appearing in the signal from the WREBUS system in the second stage; filters are being fitted to F8. Thirdly, the failure could have been occasioned by a rupture of the tank diaphragm which separates the two propellant liquids. This diaphragm may have been weakened during the preparation phase, and it appears that this is the most likely cause of the failure.
A paper in the ELDO archives has this to say about F8:
Following the F7 trial, the Secretariat tried to inculcate a greater awareness of the need for better technical discipline and control of operations during a trial. Meetings and discussions took place with Member States on the subject of inspection and defect reporting in particular. During the F8 trial, some improvement was obvious, but it is still apparent that these disciplines are not accepted as having the importance attached to them which the Secretariat would wish. The supply and control of spares was also still far from satisfactory in the upper stage areas.5
F8 was launched on 3 July 1969. Both the first and second stages functioned correctly, but after the signal was sent to separate the third stage, it appeared to explode. The RAE report suggests that the failure was identical to that of F7, and was not a mechanical malfunction but an electrical malfunction.
The subsequent RAE report describes the flight thus:
On the 12 June 1970 the vehicle was launched at 10.40 am local time… The first stage functioned correctly as predicted in the flight plan, and the second stage separated and performed as predicted. The third stage separated from the second stage and its engines ignited correctly. After engine ignition occurred the third stage helium tanks lost pressure progressively which caused the third stage engines to lose thrust and also to give intermittent thrusting. These factors gave rise to uncovering of the fuel depletion sensors and a premature engine shut down before all the propellants were used up and before orbital velocity was achieved. The satellite did in fact separate correctly from the third stage when the engine cut off signal was given.
A second major fault which occurred during the flight of the vehicle was the non-jettisoning of the satellite fairings during second stage thrusting. This fault occurred due to the unscheduled separation of a plug and socket connection between the third stage and the satellite. This plug and socket was in the circuit which should have carried the command signal to ignite the fairing jettisoning device; the continuity of this plug and socket was monitored and a disconnect was registered at +78 seconds.
The failure to achieve orbit was a combination of these two faults. Post flight calculations show that an orbit would have been achieved by the satellite even with the under-performance of the third stage had the fairings been jettisoned. On the other hand had the third stage performed correctly the complete third stage and satellite with fairings attached should have acquired orbital velocity.
A later report pinpoints the cause of the plug failure:
Investigation has shown that upon assembly of the connector, air was sealed into the cylinder at 1 atmosphere by two toroidal seals on the piston. Upon reaching a less dense atmosphere during flight, the differential pressure was sufficient to operate the piston and to separate the plug and socket. The device operated correctly in F7 and F8 because the cylinder and piston were dismantled several times before final assembly for flight. This had the effect of slightly damaging the toroidal seals and allowing a slight air leakage to occur.
There was also a problem with the pressurisation of the third stages tanks, meaning that the thrust in the last part of the flight became irregular.
For budgetary reasons, there was no F10.
F11 was the first and only flight from Kourou in South America. It was launched on 5 November 1971.
During the first stage burn, the vehicle went out of control and broke up due to a failure of the electronic guidance mounted at the top of the third stage. As the vehicle accelerated, air resistance caused the temperature of the fairings to rise, and at the same time, an electrostatic charge built up on the fairings. Air at low pressure and a high temperature can conduct relatively easily; there was a discharge from the fairings to the main third stage body which disrupted the electronic systems, leading to a loss in control.
F12 and F13 were never launched: the Europa programme was abandoned on 27 April 1973. Blue Streak never flew again.
Eleven Blue Streaks were launched: F1 to F9 (there were two F6s, F6/1 and F6/2) and F11.
F12 is at French Guiana, or parts of it are. The stainless steel tanks (which would not corrode in the equatorial heat and rain) are being used as a chicken coop.
F13 is at the Deutsches Museum, Munich.
F14 is at the Aircraft Museum at East Lothian, outside Edinburgh.
F15 is at the Euro Space Centre, Redu, Belgium.
F16 was not finally completed (and is now on display at the Space Museum at Leicester).
F17 and F18: by the time of the final cancellation these vehicles were only parts, and not fully assembled.
In addition to these vehicles, several non-flight prototypes were built. These included D1 to D4, some of which were for trials at Hatfield, others were taken to Spadeadam for static firings. Another, designated DA, was shipped to Australia before the flight vehicles, and set up on the launch site for static testing. This was to test the Woomera site and give experience to the Australian team. DB was static fired at Spadeadam to check the engines. In addition, there was a further prototype vehicle, DG, used to prove the Blue Streak launch site at Kourou, in French Guiana.