TX-16

The TX-16 was a weaponized version of the Ivy Mike device. The Mark 16 is more properly designated TX-16/EC-16 as it only existed in Experimental/Emergency Capability (EC) versions. They were called Emergency Capability Weapons, officially designated TX-16, and unofficially nicknamed Jugheads. But they had hardly come into existence before they were rendered unnecessary and obsolete.

The TX-16 was the first deployed thermonuclear weapon; and the only cryogenic TN weapon ever deployed. To do this, it was necessary to significantly reduce the weight of the device and replace the complex cryogenic system with Dewar vessels to replenish deuterium losses due to its boiling. The carrier was a modified B-36. A small number of these bombs in the EC-16 modification were produced as a response to the Soviet thermonuclear program.

The TX-16 device was designed by Richard Garwin, a student of Enrico Fermi, Richard Garwin is often credited as the author of Mike, the first hydrogen bomb design, on the suggestion of Edward Teller. Garwin’s laconic remark about what he did in the summer of 1951 after designing Mike. “After July 25th, I had some time at Los Alamos, and so I designed a deliverable, cryogenic version of Mike that would lie down rather than stand up.” (Mike was vertical.) No easy task. To meet Air Force requirements for dealing with air turbulence or hard landings, the bomb had to withstand forces up to eight “g’s” (eight times its weight). It had to be no heavier than a B-36 bomber could carry, about 35 tons. (It ended up closer to 20 tons.) And its load of deuterium had to remain frigid and liquid for many hours without mechanical refrigeration. On the ground, until takeoff time, it could be kept cold with ground-based cryogenic equipment. In the air, until its release or until the bomber returned to base, it was probably surrounded by a larger dewar filled with liquid hydrogen (ordinary hydrogen, not deuterium) — a thermos within a thermos, so to speak.

Garwin had to design it so that during a long flight the amount of deuterium allowed to escape as gas would be a small fraction of the total and the pressure within the “sausage” would be tolerable. Garwin was up to the task. His design included even innovative bolts that minimized heat flow out of the stainless-steel dewar.

A TX-16 Panel was named in mid-January 1953 to study the weapon logistics, with members from Los Alamos, the Air Force Special Weapons Center and Sandia. The Air Force was assigned the task of providing a suitable carrier and handling equipment, no small task for a weapon of this size and weight. Sandia started to design a contact fuze, which was hoped to be ready for incorporation in the early weapons. Los Alamos would handle the detailed planning and coordination for the over-all project. Sandia would design and supply theafterbody, fuze, parachute, power supply and various test devices to be usedduring assembly and flight. The weapon would be baro-fuzed and baro-fired,using standard components. Carriers would be the B-36 and the B-47 aircraft.

Wind-tunnel studies were completed by October 1953, which determined the size ofthe fins and the height of the spoiler bands. A time of fall of about 200 seconds was desired, which required the use of a parachute. The initial drop test was made December 7, 1953. Release was made at the Saltón Sea Test Base from a B-36 at 39,500-foot altitude and 300-knot airspeed. This was a free-fall drop of about 52 seconds. The bomb started to pitch after release, but this motion soon damped out. Rockets were then fired to create both pitch and yaw oscillations, but these also damped out during the trajectory. Subsequent tests were made, with and without parachutes, at both Edwards Air Force Base and the Saltón Sea Test Base. The tests ended April 13, 1954, and good ballistic results were obtained.

Los Alamos requested an evaluation of the weapon afterbody under conditions of 40-percent overload at the time of parachute opening. Sandia calculated that an 80-foot-diameter parachute would result in an opening shock of 7 g's. Subsequent static testing showed that the afterbody would absorb this overload shock with a 1.22 factor of safety.

Sandia released its part of the TX-16 design April 15, 1954, with provisions forair burst only. It was hoped to later introduce the proximity fuze that had been developed for the TX-15, on a time scale that would not interfere with the TX-15 program.

The length of the bomb TX-16 was 7.54 m, diameter - 1.56 m, weight 17.69 - 19.05 t. The design capacity was 6-8 Mt. In January 1954, 5 bombs were produced under the designation EC-16. A simplified and lightened bomb version (the EC-16) was prepared and scheduled to be tested in operation Castle Yankee, as a backup in case the non-cryogenic "Shrimp" fusion device (tested in Castle Bravo) failed to work; that test was cancelled when the Bravo device was tested successfully.

After the successful test of Castle Bravo "Shrimp" it became obvious that the EC-16 was hopelessly outdated. By April 1954, they had been disarmed, since by that time devices with solid fusion fuel that did not require cryogenic systems had been successfully tested.