Problems with Black Arrow's engines slowed progress, and the original launch date target in 1968 could not be met. However, by 1969 the programme finally approached its 'moment of truth'.

The launch programme was reduced from the proposed five launches to just three. This meant that an orbital attempt would have to be made on only the second mission. The first vehicle, Black Arrow R0, would consist of two live stages and a dummy third. The next launch, Black Arrow R1, would orbit a simple developmental satellite. Black Arrow R2 would be the first to carry a fully working satellite into orbit.

R0: delays and launch
The launch of R0 had been scheduled for January 1968, just 16 months after the programme was given the go-ahead. Such a tight timetable left little room for manoeuvre if problems developed, and unfortunately they did--the engines ran into trouble during testing, and had to be modified. This in itself was not unusual in such a project, but the programme's reduced level of funding meant that there were not enough spares to cope with the setback, and this added to the delays. It was April 1969 before the problems were solved, and the Black Arrow launch teams were able to begin their journeys to Woomera, South Australia. This had been picked as the location for launch because of the low population density of the area. The risk of explosions was substantial, and no area of Britain lay far enough away from inhabited areas to be considered safe.

GKN Aerospace

Black Arrow R0 seconds after lift-off. The Black Arrow (and Black Knight) vehicles were held down until the 'instant of move' (lift-off) by a pneumatic release jack clamped to the underside of the first stage. When the engine's chambers reached their designated pressures, the jack was released and the vehicle rose steadily into the air. The steam clouds are produced by the engine's heat vaporising thousands of litres of exhaust-duct cooling water.

On 23 June 1968, everything was in place and R0 was declared ready for launching. The countdown started... and then stopped almost immediately: R0's flight sequence programmer had failed. The fault was fixed, but in the meantime low cloud had moved over the launch site. This would obscure R0 from the tracking cameras as it climbed, and so the launch attempt was abandoned for the day. Five days later the weather had improved and the countdown resumed. At 08.20 on 28 June the R0's mighty engine roared into life and lifted the first Black Arrow launch vehicle into the air. The launch programme had finally begun.

R0: failure and enquiry
Within seconds R0 started to twist and corkscrew. Something was clearly very wrong. The violent oscillations continued, and the dummy third stage was wrenched clear. The damaged vehicle continued its tortuous climb through the shimmering air. At a height of 8km it started to keel over and tumble. When it had fallen to an altitude of just under 3km, the range safety officer destroyed the vehicle--manganese dioxide was injected into the HTP tanks and R0 exploded. As debris rained over the parched orange soil of the Australian desert, the launch teams wondered what had caused the vehicle to malfunction.

The vehicle's data indicated that one of R0's four engine pairs had been repeatedly moving from one end of its movement range to the other. An enquiry team at the RAE in England ran computer simulations that indicated that this violent movement had almost certainly been caused by a loss of signal, probably as a result of a broken wire.

R1: repeat and success
Such a failure was entirely typical of the problems that can beset rocketry programmes. All new launch vehicles suffer failures during development, and R0 was just such a developmental launch. But it was a major setback for the already tight Black Arrow launch schedule. The next vehicle, Black Arrow R1, would now have to repeat the intended mission of R1, rather than attempt a launch of the developmental satellite. This meant that R1, still in England on the Isle of Wight, would have to be reconfigured to R0 specifications before being sent to Australia. This was duly done and R1 was made ready for launching in February 1970, before suffering a series of curtailed launch attempts because of more poor weather. Finally, at 06.45 on 4 March, R1 was launched in a repeat of R0's northwesterly trajectory over the Australian desert. This time the vehicle performed perfectly. The various teams in Australia and England breathed a collective sigh of relief as the Black Arrow programme came back on course. All was now set for the launch of the fully-functioning three-stage R2 vehicle and its X2 satellite.

R2: orbital attempt
However the delays continued. A shortage of available ships meant that R2 had to wait on the Isle of Wight for a month. This was probably a good thing, because operations were not running smoothly at Woomera either: the launch site was suffering from a faulty water supply and a still-unfinished nitrogen-gas feed, while the HTP propellant was late arriving from Sydney. Eventually, on 1 September 1970, R2 was ready for launch. The countdown started... and then stopped with 35 seconds to go, because of a fault at one of the tracking stations. An immediate investigation showed the station to be in error, but the delay meant that the launch had to be abandoned for the day. The countdown was resumed the following morning and at 10.04 R2 thundered into the air.

The R2 rocket climbed perfectly and arced gracefully to the north, the setbacks of the past year apparently evaporating in its wake. But after the first stage had separated, it became clear to technicians on the ground that something was wrong. Vehicle data and tracking readings indicated that the engine of the second stage was losing thrust. It then shut down altogether, almost 30 seconds earlier than it should have done. Despite this, R2 continued its ascent. Second-stage separation passed without incident and the Waxwing motor of the third stage ignited successfully. However, the reduced performance of the second-stage engine meant that the third stage was lacking in speed, and the Waxwing, despite performing flawlessly, could not compensate for this. When the X2 satellite separated from the third stage, both were travelling too slowly to stay in orbit. Earth's gravity prevailed, and both Waxwing and X2 splashed down south of the Arafura Sea in the Gulf of Carpentaria.

The enquiry into this mission failure revealed a faulty propellant-tank pressurisation system in the second stage, which had caused nitrogen to be vented in error. This meant that there was insufficient gas to maintain the HTP tank's pressure, and the engine was starved of HTP. In turn, this led to the decrease in engine thrust and, eventually, to the shutting-down of the engine.

The implications of this latest setback for the Black Arrow programme were serious. Teams in Britain and Australia carried out an urgent and rigorous review of the entire Black Arrow vehicle design. They concluded, however, that, although some minor modifications were needed, there were no fundamental faults in the vehicle design and the execution of the programme. The performance of R2 was put down as a 'spiritual success', and the teams prepared for the greatest challenge yet: the launch of R3 and its X3 payload, the first fully working satellite.

R3: ascent to orbit
Progress was once again painfully slow. The enforced delay caused by the inquiries into the R2 mission and the whole Black Arrow programme was compounded when more problems developed with R3's engines. Then, an industrial dispute at Rolls-Royce, now the parent company of Bristol Siddeley, led to further delay. Even worse, the subcontractor that had been supplying the engine combustion chambers to Rolls-Royce closed its production line. The launch of R3 was pushed back to October 1971.

On the blazing hot afternoon of 28 October everything was set. At 13.38 and 46 seconds, R3's engines were started. Its eight chambers shook and swayed as thrust built up. Four seconds later R3 started climbing gradually away from the swirling desert dust, inclined away from the vertical, and roared on towards orbit.

When R3's velocity had risen to a little under 7.8km/sec., at an altitude of almost 620km, the rocket hardware dropped back, leaving the satellite on its own in space. For the first 11 minutes of the mission, radio data had been flooding into the Australian receiving stations. When, 39 minutes later, signals were received at the Fairbanks receiving station in Alaska, USA, the Black Arrow teams knew that X3 was in orbit. It was duly renamed Prospero. There were celebrations across the globe as Prospero passed overhead. Britain had finally launched its own satellite.

R.I.P
However, after jubilation came sadness as the hollow nature of this success sank in. For three months, the Black Arrow teams in Australia and in Britain had soldiered on, despite knowing that R3 would be the final Black Arrow launch. On 29 July 1971, Britain's minister for aerospace, Frederick Corfield, had announced to the House of Commons the cancellation of the Black Arrow programme. The launch of R3 would be the last, and the last opportunity for Britain to place a satellite in orbit using Black Arrow. The next in the satellite series, X4, would be launched on a NASA Scout vehicle, and then the satellite programme itself would end, the planned follow-on satellites never to be built. After the success of R3, Britain had become the sixth nation to launch its own satellite, but the first to then abandon that capability.