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Flight Journal - - CONTENTS - By John Lockwood

Rock­oons: A Short Chap­ter in At­mo­spheric Re­search

At first glance, rock­ets and bal­loons would ap­pear to be en­tirely separate tech­no­log­i­cal species that would have lit­tle to do with one an­other. A mod­ern rocket is a highly com­plex feat of engi­neer­ing and, if pow­er­ful enough, can es­cape the Earth al­to­gether. A bal­loon is as sim­ple as sim­ple gets (within rea­son), but even mod­ern re­search bal­loons can’t get higher than about 20 miles. But what if the two were com­bined?

In com­bin­ing the two, the bal­loon acts as a pas­sive booster by hoist­ing the rocket high enough that it gives the rocket a head start be­fore it is fired, thereby al­low­ing it to take off in the up­per at­mos­phere—less air re­sis­tance and fric­tion to worry about. In the 1950s, the U.S. govern­ment in­ves­ti­gated the con­cept for up­per at­mo­spheric and outer space re­search. In­evitably, per­haps, the re­sults were called “rock­oons.”

By 1952, the U.S. Navy was launch­ing 100-foot-wide bal­loons, each with a sin­gle-stage rocket dan­gling by a tether be­neath it. The Navy was us­ing Dea­con rock­ets, some of which were 10 feet long and 8 inches in di­am­e­ter.

When the bal­loon reached its max­i­mum al­ti­tude, the low­er­ing air pres­sure tripped a re­lay that au­to­mat­i­cally ig­nited the rocket, which then reached an al­ti­tude of some 40 miles, well above most of the earth’s at­mos­phere. The rocket used solid fuel.

A Geiger counter or ion­iza­tion cham­ber in the nose would then mea­sure and an­a­lyze cos­mic ra­di­a­tion in its nat­u­ral en­vi­ron­ment, free of most of the in­ter­fer­ence from Earth’s at­mos­phere. The find­ings were ra­dioed back to Earth, and the spent rocket came down some­where in the oceanic fir­ing range.

By 1957, the U.S. Air Force was also try­ing out rock­oons, un­der the name of “Project Far Side” (no...it pre­dated Gary Lar­son’s car­toon strip), with a bud­get of $750,000 ($6.6 mil­lion in to­day’s dol­lars). The rocket as­sem­bly was larger than that used by the Navy and had four stages, but it was still solid fuel.

The first stage con­sisted of four Re­cruit rock­ets, the sec­ond stage was a sin­gle Re­cruit, the third had four smaller Ar­row 2 rock­ets, and the fi­nal stage was a sin­gle Ar­row 2. All told, the en­tire as­sem­bly had a com­bined thrust of 220,000 pounds, com­pared to, for in­stance, the later Saturn V moon rocket, which had an over­all thrust of 7,500,000 pounds.

Rather than be­ing fired au­to­mat­i­cally by low­er­ing pres­sure, as with the Navy units, a ra­dio com­mand from the ground would ig­nite the four-stage as­sem­bly, which would shoot up straight through the bal­loon. The launch fa­cil­ity was lo­cated on the is­land of Eni­we­tok in the Pa­cific Ocean.

The Air Force bal­loons were much larger than the ones used by the Navy, some be­ing 200 feet in di­am­e­ter. The heav­ier rocket re­quired a much larger bal­loon, which was, in fact, the largest bal­loon con­structed up to that time. It was made out of thin poly­eth­yl­ene (2ml thick) and used he­lium for lift.

Project Far Side had six planned launches, with the first oc­cur­ring Septem­ber 25, 1957. The first five launches were fail­ures. The project was dogged by bad luck: bal­loons failed, the rock­ets mal­func­tioned, or the in­stru­ments didn’t work.

But the sixth launch suc­ceeded. It took off on Oc­to­ber 22, 1957, just 18 days af­ter the Soviet Union suc­cess­fully launched hu­man­ity’s first artificial satel­lite, Sput­nik I, on Oc­to­ber 4.

The sixth as­sem­bly reached a height of about 4,000 miles, with a sci­en­tific pay­load of only 3 1/2 pounds. The pre­vi­ous Amer­i­can record was 650 miles, us­ing the Jupiter-C, a much larger rocket—too large for any avail­able bal­loon to carry.

The four-stage rocket reached a max­i­mum speed of at least 17,000 miles an hour, or­bital speed, but since the tra­jec­tory was straight up, it did not go into or­bit. It, in­stead, fell back to Earth, burn­ing up from air fric­tion—but not be­fore ra­dio­ing its find­ings.

One of the Project’s more en­thu­si­as­tic mem­bers claimed the data thus gath­ered was more valu­able than that from Sput­nik I.

There was also talk of try­ing it out with a fifth stage, in hopes of reach­ing the Moon, though noth­ing came of it. Send­ing in­stru­ments and peo­ple to the Moon would have to wait for rock­ets far greater than even the Jupiter-C, and at­mo­spheric re­search leapfrogged well past rock­oons with the ad­vent of vi­able satel­lite tech­nol­ogy.

In the golden age of space ex­plo­ration and ever-grow­ing booster rock­ets, Project Far Side used bal­loons to de­feat the lower at­mos­phere and bun­dled rock­ets to act as staged boost­ers. (Photo cour­tesy of Wiki­me­dia Com­mons)

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