Cloudbase is the operational headquarters of international security organisation Spectrum, from Captain Scarlet And The Mysterons. In the New Captain Scarlet series, it is called Skybase.
Originally conceived as a security organisation, Spectrum needed an HQ that could be top-secret yet easily accessible to its operatives. Early designs for a submarine, a space station, a floating island, and a Saharan complex were rejected. Ultimately, plans were approved for an aircraft carrier-like structure that was able to float on the edge of Earth's atmosphere using a combination of turbo fans and newly-developed anti-gravity
Cloudbase hovers in the troposphere at a height of 40,000 feet and can be moved above any point on Earth as needed. Due to its altitude, the entire structure is pressurized; pilots entering or leaving aircraft on the flight deck, do so inside airtight capsules.
Cloudbase is built from fleetonium alloy at an unnamed world government research depot in Stockholm, Sweden. It was made into fifty separate sections prefabricated and assembled in outer space, supervised by Colonel Conrad Turner of WSP from an abandoned satellite.
Cloudbase is 630 feet long and 330 foot wide, from where the 593 person crew of field agents (the Captains), pilots, medical, administrative and maintenance staff operate. It has a flight deck, control room sleeping facilities etc, just like an aircraft carrier.
In the Generator Room is a vast complex of more than 20 Cahelium engines working on the unique task of converting the sun's rays into energy. The engines provide enough power to enable Cloudbase to be held aloft by it's 4 vertical-thrust, air-ducting, hover "combines" (producing 500 tons per square centimeter, 2,688,000 Lbs PSO thrust). It also has horizontal thrusters able to propel it to any point around the world in a matter of hours. These atomic jets are powered by air-intake, nacelle located, nuclear-powered, cloud-vapor conversion jets.
The Captains, Angels and some administration staff (such as Colonel White and Lieutenant Green) usually work on a four hours on call/four hours off basis, with four hours on/two off in emergencies.
In the hyperactive Control Room are; Colonel White's control desk, itself a vast computer and Lieutenant Green's communications console. From his desk the Colonel is able to contact all the world's companies, any individuals, Spectrum's auxiliary forces and world government groups. From his communications console, with its own color-coded chart, the Lieutenant is able to help decipher Mysteron threats, and use this communications console to record, file and recall for further use vast amounts of information necessary for the maintenance of Cloudbase it'self.
Adjacent to this main Control Room is a short, curved, tunnel-like gallery. This observation tube is constructed from some clear a giving all-round clear visibility of the area surrounding Cloudbase. From all over the world information is radioed automatically through Cloudbase telecommunications systems in the Observations Room (or various worldwide Spectrum Information Centres), where it is identified, sorted, gauged on importance values, and passed on for storage. The observation room houses the Spectragram, the video-scanners, astroscopes, space-mascope. From this room, at the flick of a switch, any part of Earth can be scanned through observation satellites scattered above the Earth . The Spectragram is the radar defence of Cloudbase. Registering any object coming within a 500-miles radius of Cloudbase.
All members of Spectrum personnel (Captains, Angels, security officers, etc) are connected to Cloudbase by their radio-transceivers, linking them with the communications network of Lieutenant Green's desk. Every member of staff must make at least two daily reports to Lieutenant Green.
Other information is also relayed through to Colonel White and Lieutenant Green through Spectrum's communications section and the Spectrum Information Centers. Every major city on Earth, barring Bereznik, has some form of Information bureau (a Spectrum Information Centre or otherwise), linking them with Cloudbase.
The medical bay, the size of a small hospital, is manned by Doctor Fawn staff. It includes an isolation ward and operating theater and many other facilities.
Radar Room, for tracking aircraft, rockets and missiles; Colonel Whites Conference Room for important meetings; Room of Sleep for crew rest; Amber Room, where pilots (all female), stand by for action; Lounge, for all Cloudbase crew to relax between shifts.
Various types of aircraft are carried by Cloudbase. Among them are, Spectrum Passenger Jets, Magnocopters using the lower flight deck; [Interceptor fighters]] which are launched from the upper flight deck. the Interceptors are maintained below the flight deck.
Cloudbase's primary defense is the squadron of Angel Interceptor fighter aircraft. At least one fighter is in the air at all times, while the other two are kept on permanent standby; electron ray discharge air-to-air missiles; hypersonic paralyzing cannons.
Cloudbase was a six-foot model designed by Derek Meddings, filmed in front of a painted sky backdrop. Too heavy to be supported by wires, the model was held in the air by metal supports, which were concealed behind it.