FLUG REVUE August 2003: The weathermen of Cape Canaveral

THE WEATHERMEN OF CAPE CANAVERAL

By Matthias Gründer

At Cape Canaveral, nothing runs without the US Air Force. Amongst the general public, satellite launches and the Cape are often mentioned in the same breath as NASA, but the fact is that only in the Kennedy Space Center to the north of the extensive site does NASA actually have the last word. All the other launch complexes for military missiles and satellite launchers are located on the grounds of Patrick Air Force Base, founded in 1947, also known as Cape Canaveral Air Force Station or Air Force Eastern Space and Missile Center or Eastern Test Range. One of the most unusual USAF units is stationed here, the 45th Space Wing of Air Force Space Command.

The Operations Group of this wing includes not only two launch squadrons but also one weather squadron, and it is no accident that the latter is mentioned immediately after the launch teams. The servicemen and civilians in this unit screen the airspace above Cape Canaveral all around the clock so as to be prepared for the rigours of the weather in good time. To do this they use a mixture of wide-area satellite reconnaissance, radar surveillance and releases of balloons equipped with radiosondes.

Florida and its calm, hot climate – this cliché is often used, not least by public agencies in this self-styled “Sun State” and its inhabitants. Most of the year it is in fact true, but one should not rely on it, not least given the proximity of the Caribbean and its unpredictable weather. That is why the 45th Weather Squadron's website is also one the most visited in the state. There are even separate pages for storm and lightning warnings, and in the case of launches that have been announced a separate preview is prepared for each launch complex, with continuous updates if required.

Virtually everyone who works at the Cape needs the weather information for their work. “As soon as one launch is over, we start preparing for the next one,” is the rule here, and sometimes it gets particularly hectic. Launch preparations start with delivery of the satellites or other payloads, which these days usually arrive by air. Calm weather is essential to the flight of such a super transporter, with its priceless cargo onboard, but shiploads bound for the harbour of the spaceport need to know the weather situation as well.

Next comes the setup and assembly of the launch systems which, apart from the Shuttles and the Titan space launch vehicles, to all intents and purposes take place outdoors, except that they are surrounded by an assembly tower which simultaneously offers protection against rain, wind and lightning. The individual stages are brought by truck and then mounted suspended by crane hook. Especially tricky is the phase in which a launch vehicle is connected up with any solid fuel boosters that may be required, as these are powder kegs in the truest sense of the word and are handled like raw eggs. Here too, as in the subsequent phase of fuelling the rocket with the various fuel components, confirmation is needed from the meteorologists to ensure that the weather will be calm and mild while the work is carried out.

Meanwhile, as previously mentioned, the Shuttles and the Titan launchers have large assembly hangars which can even withstand hurricanes. But only the assembly work is carried out there; installing the payload and refuelling has to be carried out on the ramp – once again, a case for the meteorologists. All these jobs – some 5,000 per year – are described as “weather-sensitive” on the Cape. Even if all the launch complexes or pads, as they are known for short, have a sufficient number of giant steel masts with lightning conductors, one would not want to tempt Providence, especially as there have been cases in the past where thunderstorms wreaked unpleasant surprises on the launch teams.

Even today, space veterans at the Cape think back with a shudder to the launch of the Apollo 12 Mission on 14 November 1969 when, shortly after takeoff, the primary onboard power supply failed because the Saturn launch vehicle was twice struck by lightning during lift-off. When films of the launch were subsequently analysed, it turned out that a terrestrial lightning strike was following the launch vehicle when this was already above the clouds – yet there were three men, priceless lunar flight equipment and 10,000 litres of highly explosive fuel on board!

Even today one can guarantee that if the launch window for a particular mission is tight, then a bad weather zone will be on its way so that the weathermen will be in for a difficult time: can we get the thing up before the storm is on us, or will we have to call it all off? The meteorologists always have the last word, and they have the power to abort a takeoff even after the countdown has started.

The phase immediately before a launch is particularly busy. The crew and the security forces need information on wind, temperature, clouds, smog levels, air density, humidity and many other parameters as well. There are 23 measurement systems located all over the launchpads that collect this data, and some 900 sensors generate 9 gigabytes of data every day. According to its own data, the 45th Weather Squadron thus has the densest measuring network in the world.

Eight hours before the launch, special radiosondes are launched with hydrogen-filled balloons for radar surveillance. Up to the start of the mission, twelve of these miniature direction finding sensors climb to an altitude of 35 kilometres and transmit back information on wind direction, wind speed and air density, as one cannot assume that if the weather is splendid on the ground this will automatically be the case at altitude as well. And if a bad weather front or even a high-speed hurricane is advancing from the Caribbean, then the alarm bells will sound shrilly at the Cape, as that means that a Shuttle will have to be taken back to the assembly building, which can shelter two of the billion-dollar space transport systems, acting as a “safe harbour”. The vertical assembly building was built at great expense specifically for this purpose.

In the case of Shuttle launches, the meteorologists provide a lot of additional data, such as the shipping forecast for rescue ships, the meteorological report for the surveillance aircraft and search and rescue helicopters and forecasts for any emergency airfields all over the world that might need to be used. Only if all this data is favourable can the green light be given for the mission to go ahead.

Equally extensive is the workload associated with Shuttle landings. Once again six-and-a-half hours before the planned touchdown up to five radiosondes are launched and information is gathered on the weather over the entire flight route. On more than one occasion Shuttle landings at Cape Canaveral have had to be postponed by a few days. If things get tight, a landing at Edwards AFB in California is one possibility, but this is an option they would prefer to avoid, as piggybacking the orbiter back to the east coast on a Boeing 747SCA (Shuttle Carrier Aircraft) is enormously expensive. However, if this is unavoidable, then once again the weathermen will be consulted in the run-up to such a flight.

But however reliable their work is, the meteorologists are powerless to prevent failures for technical reasons. In the Challenger disaster, for example, as far as they were concerned the weather conditions for the launch were ideal. However, the porous seals on the booster segments were out of their control, as was the break-up of the Columbia at the beginning of this year. Even unmanned flights can hit the men and women of the 45th Weather Squadron hard, for example, if a launcher fails to deliver its payload as planned despite ideal weather conditions. And even if the Shuttle orbiters are grounded at present until the cause of the catastrophe is fully explained, the Weather Squadron cannot take it easy. New payloads are being delivered to the Cape and launches are following in rapid succession, almost as if it were necessary to demonstrate to the world that US space flight is still alive and kicking. And so it will remain – not least thanks to the weathermen at the Cape.

From page 38 of FLUG REVUE 8/2003

Last updated 7 July 2003

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