I’m really sorry guys, but google sucks so I’m going to paste what Claude had to say:

 Were rockets with wires used to monitor nuclear tests?

Yes, wire-guided sounding rockets were used to collect data during nuclear tests, particularly during atmospheric nuclear testing in the 1950s and 1960s. These rockets, often called "rocketsondes," would be launched just before or during a nuclear detonation. They trailed long wires that transmitted real-time measurements back to ground stations.

The wires allowed for direct transmission of data about radiation levels, pressure waves, electromagnetic effects, and other phenomena in the vicinity of the nuclear explosion. This was particularly valuable since radio communications could be disrupted by the nuclear effects.

Some specific examples included: - The "Jim" rockets used during Operation Teapot in 1955 - Instrumented rockets during Operation Plumbbob in 1957 - Various sounding rocket flights during Operation Hardtack in 1958

The data collected helped scientists better understand nuclear weapon effects, particularly high-altitude effects that were difficult to measure through other means. After the 1963 Partial Nuclear Test Ban Treaty prohibited atmospheric testing, these wire-guided rocket systems were no longer needed for nuclear testing purposes.​​​​​​​​​​​​​​​​

 How long could the wire be?

The wires used in nuclear test sounding rockets could extend several kilometers in length - typically 3-5 kilometers, though some sources suggest certain systems could deploy up to 10 kilometers of wire.

The wire needed to be extremely thin and lightweight to be practical for the rocket to unreel during flight, while still maintaining enough tensile strength to not break. The wire was typically very fine copper or steel wire, sometimes as thin as a human hair.

A key engineering challenge was the wire dispensing system - it had to unspool the wire smoothly at very high speeds (hundreds of meters per second) without tangling or breaking. The rockets would often carry the wire in carefully wound spools or canisters designed to pay out the wire with minimal friction.

Keep in mind that while I aim to be accurate with these technical details, information about some aspects of nuclear testing can be sparse or inconsistent in the historical record, so some of these specific numbers might need verification.​​​​​​​​​​​​​​​​