WRE HAD Rocket Experiments

Australia’s fledgling space program had been conducting a series of high altitude density (HAD) experiments at Woomera using rockets designed and built by the Weapons Research Establishment (WRE). Each experiment ejected a 2m diameter inflatable radar-reflective spherical balloon at 130-Km high to fall at speeds of up to 3200 Km/hr until it collapsed at about 30-Km high. Analysis of radar measurements of the falling sphere produced data on air density and temperature as well as wind direction and speed. Scientists believed simultaneous launches at Carnarvon and Woomera would yield valuable knowledge of “atmospheric tides … [and the] zonal travel of mesospheric disturbances.” [1]

The Carnarvon launches

A transportable rocket launcher set up in mid-1964 on a dry clay pan between the Carnarvon Space Tracking Station (CRO) and the Town of Carnarvon commenced launching HAD rockets 48 Km into Shark Bay in a south-west direction well past the town. CRO lacked Woomera’s sophisticated kine-theodolite optical tracking system so a VHF beacon installed in each rocket enabled AcqAid to track them and provide pointing data for Q6. The launcher-CRO interface was tested with a few trial firings - and the ‘comedy’ began

The AcqAid antennas (set to linear polarisation to match the beacon and giving an extra 3db gain) failed to acquire the first trial rocket; the signal continuously fading in and out. A spare beacon set up on the Q6 collimation tower indicated no problems so more trial firings were conducted. The next acquisition attempt also failed; probably hindered by the stronger signal from the collimation beacon which had unfortunately been left on. An argument ensued as to whether circular polarisation on the AcqAid antennas would be better suited to the fast spin-stabilisation of the rockets; it was decided to try one antenna on left polarization and the other on right. AcqAid was now able to track and provide pointing data to Q6. [2]

But then it was Q6’s turn to create problems. They tracked a couple of launches successfully but an engineer had forgotten to remove the ‘write-lockout ring’ on the computer magnetic-tape reel consequently no data was recorded. He can still remember the look of horror on the Operations Supervisor face when he told him. [3]

Meanwhile down at the launch pad a different ‘comedy’ was developing - apart from several rocket failures. The clay pan was not as firm as they thought. As each rocket was fired, its exhaust apparently drove the two rear pads of the launcher base a little deeper into the clay pan incrementally increasing the launch elevation angle. Eventually one rocket impacted on the edge of the town airport rather than far into Shark Bay. The next landed on the levy bank near the Gascoyne Hotel where a PWD crew was working on the water main. Leading-hand Ray Sharp recalls it clearly: “A large piece of the rocket just missed one of my crew. He stormed off, reckoning I was trying to kill him”; Ray still has a small rocket fragment as a memento. [4]

Everyone learnt from those first rocket firings. AcqAid and Q6 realised that ‘mission check lists’ were as necessary for local exercises as they were for NASA missions. The launch crew learnt to check their elevation angle before each firing. However, caution being the better part of valour, the launch site was moved to the rocky foundation of cliffs near Quobba Station, 60Km north of CRO. The public was invited to view the next launch series from a vantage point near Quobba Point lighthouse. But before the experiments resumed, a light aircraft carrying a beacon, was flown over the new launch site dropping aluminium pudding-bowls to be sure Q6 could distinguish the radar echoes of an aluminium bowl from that of the launch vehicle (the aircraft).

The Quobba launches were more successful. In mid-July rockets were launched within 1½ hours of local midday; two at Quobba and four at Woomera. They all reached a height of about 115 Km. Then late in October four attempts at Quobba yielded two results; one shortly before dawn and one shortly after dusk. More launches followed in May 1965. [5] These simultaneous ‘falling sphere’ experiments are still considered one of the best sets of seasonal atmosphere data ever gathered.

References

[1] Minister for Supply, press release, September, 1964. Note: CRO was the only other place in Australia with radar accurate enough for the experiments
[2] Goldsmith, E., email to PD, date???
[3] Main, P., email to PD, 31 July 2005
[4] Sharp, R., phone conversation with PD, May 2005
[5] NAA: PP538/S2, B87, DoS item 93, 22 October 1964