DEACON ROCKOON (Rocket-Balloon) - SUI-18

The so called ROCKOON (Rocket-Balloon) technique allowed small rockets to reach higher altitudes by sending it onboard a stratospheric balloon to an altitude of about 70.000 ft where it was fired either by an onboard timer, a pressure switch or by telecommand. The technique was first used in 1952 by Dr. James Van Allen then working at the State University of Iowa.

The main advantage of the rockoon combination was to let the rocket to pass throught the lower and thicker layers of the atmosphere without using its own propulsion power, which then allowed a higher apogee to be reched. The only setback was that once released, the balloons cannot be steered and consequently the rocket's launch direction nor imapct area can be predicted. Thus, for safety reasons, all the Rockoon missions were conducted from small vessels sailing in open waters. This possed an additional advantage as the ships could move with the wind to create a ""zero wind condition"" ideal to launch the balloons.

The first rockoon firings used a high-performance small vector known as DEACON. It was a vertically launched sounding rocket developed in 1947 by Allegany Balistics Laboratory for the Navy Bureau of Ordnance, and originally designed to carry a 50-pound instrument load to an altitude of about 20 miles. It had no internal controls or movable surfaces and was arrow stabillized by fins at the after end of the rocket. Propulsion was furnished by a JATO X220 solid propellant rocket motor. Its total length was 12.3 ft, diameter 6.5 inches and fin span was 38.9 inches. The Deacon was capable of attaining speeds about 3.000 mph, and altitudes in excess of 60 miles when fired from a balloon floating around 70.000 ft.

Balloon launched on: 8/30/1953 at 13:59 utc
Launch site: USCGC Eastwind (WAGB 279)  
Balloon launched by: General Mills Inc.
Balloon manufacturer/size/composition: Zero Pressure Balloon General Mills -- 55 foot
Flight identification number: GMI-1025
End of flight (L for landing time, W for last contact, otherwise termination time): 8/30/1953
Landing site: Payload no recoverable

The purpose of the flight was to make measurements of cosmic radiation in the auroral zone.

The balloon was launched on August 30th, 1953 at 13:59 utc, from the deck of the U.S Coast Guard vessel Eastwind sailing at coordinates 53º06'N - 55º05'W. The balloon failed to reach float altitude due to a leak. About 15:05 utc while it floated at 51.500 ft the telemetry signal was lost. As a result the rocket was not fired.

• Final report ANNEX IX (High Altitude Balloon Research) General Mills Inc. Mechanical division April 1954
• Upper Atmosphere Research Report Number 21. Summary of Upper Atmosphere Rocket Research Firings Naval Research Lab., Feb. 1954