DEACON ROCKOON (Rocket-Balloon) - SUI-01

The so-called ROCKOON (Rocket-Balloon) technique enabled small rockets to reach higher altitudes by launching them from a stratospheric balloon. The balloon would ascend to approximately 70,000 feet, where the rocket was fired using an onboard timer, a pressure switch, or telecommand. This innovative method was first employed in 1952 by Dr. James Van Allen, who was working at the State University of Iowa at the time.

The primary advantage of the rockoon combination was that it allowed the rocket to bypass the denser, lower layers of the atmosphere without expending its own propulsion energy. This resulted in a higher achievable apogee. However, the technique had a limitation: once released, the balloons could not be steered, making it impossible to precisely predict the rocket's launch direction or impact area. To address this safety concern, all rockoon missions were conducted from small vessels operating in open waters. This approach offered an additional benefit, as the ships could adjust their position to create "zero wind conditions," ideal for balloon launches.

The initial rockoon launches utilized a high-performance, small rocket known as DEACON. Developed in 1947 by Allegany Ballistics Laboratory for the Navy Bureau of Ordnance, the Deacon was originally designed to carry a 50-pound instrument payload to an altitude of approximately 20 miles. The rocket had no internal controls or movable surfaces and relied on fin-based arrow stabilization at its rear. Propulsion was provided by a JATO X220 solid propellant rocket motor. The Deacon measured 12.3 feet in length, had a diameter of 6.5 inches, and featured a fin span of 38.9 inches. When launched from a balloon at an altitude of around 70,000 feet, it could achieve speeds of approximately 3,000 mph and altitudes exceeding 60 miles.

The objective of this flight was to perform absolute measurements of the total intensity of charged primary cosmic rays, extending to the lowest feasible levels of magnetic rigidity. The PAYLOAD included a Victoreen 1B85 Geiger counter housed in the rocket's nose section. This section, approximately conical in shape, was pressurized, detachable, and had a volume of about 2.5 cubic feet. The schematic diagram at left above illustrates the internal distribution of instruments: (1) Geiger Counter, (2) Thin fiber plate and cathode follower, (3) Circuitry, (4) Audio-oscillator for the radio transmitter, (5-9) Batteries, and (10) Telemetry transmitter. Additionally, a small rocket-firing gondola -containing a timer, barometric pressure switch, and firing batteries- was suspended from the rocket's tail fins by a lightweight cord, allowing the rocket to detach cleanly when fired.

Balloon launched on: 8/21/1952 at 1:25 EST
Launch site: USCGC Eastwind (WAGB 279) anclado en la Bahia de Baffin entre Groenlandia y el NE de Canada (Lat. 80.10º N - Lon. 68.47º O)
Balloon launched by: General Mills Inc.
Balloon manufacturer/size/composition: Zero Pressure Balloon General Mills - 55 ft
Flight identification number: GMI-952
End of flight (L for landing time, W for last contact, otherwise termination time): 8/21/1952
Landing site: Payload no recoverable

The balloon was launched on August 21th, 1952 from the deck of the U.S Coast Guard vessel Eastwind, sailing at coordinates 80º6'N - 68º28'W. While ascending the balloon entered a cloud deck. Through breaks in the clouds the balloon was observed to be fully inflated, indicating pressure altitude had been reached, but the rocket failed to fire due to a faulty firing circuit.

• Cosmic-Ray Intensity above the Atmosphere at High Latitudes Physical Review, Vol 99 Nº 1 p. 198
• Deacon rocket launches log Jonathan McDowell's website
• Final Report Project 85006 General Mills - 1953
• Upper Atmosphere Research Report Number 21. Summary of Upper Atmosphere Rocket Research Firings Naval Research Lab., Feb. 1954