Researching NASA's experiments in recovering Mercury-Redstone boosters (here) led me to researching Redstone booster serial numbers (here) aided greatly by Heroic Relics, Encyclopedia Astronautica, Jim Ryan's "My Army Redstone Days" and, later, by Gunter's Space Page. Unfortunately the Redstone components with which I am most familiar with are part of a collection which is not fully documented. While studying the components for hints as to the serial numbers, I found a note on Heroic Relics that pointed out that the gold/brass-colored piece pictured below (at the aft end of the body unit) is a mystery:

 Picture originally by Mike @ Heroic Relics

Picture originally by Mike @ Heroic Relics

On displayed Redstones, it's unique to the Cosmosphere's unit. Intrigued, I started by emailing Jim Ryan of My Army Redstone Days to see if a field artillery veteran would recognize the piece. He did not, but suggested the component was related to calibrating the missile prior to its being dispersed to a field unit. From this, I concluded that the component did not appear on tactical missiles in the field, leaving two or three possibilities: 1) that it was used in the manufacturing process, 2) that it was used in acceptance testing or battalion level operations, and 3) that it was used in non-tactical scenarios or tests. 

(1) was easy to rule out: thanks to Jim Ryan's collection of pictures I found no instances of the component during manufacturing.

(2) also became unlikely on reading the technical documentation he had, though still possible.

(3) was the most likely candidate. Since Jim didn't remember seeing it, I focused on post-retirement projects that involved the Redstone. This meant it could have been added during Chrysler's refurbishment of the vehicles, of which I found very few pictures. It didn't appear in any photos of Project Sparta, and there seem to be no pictures of the Redstones involved in Project Defender or Nike intercept tests. Another Redstone project was the Television Feasibility Demonstration, where the TV Reconnaissance Capsule "TV-1" would be ejected from the missile to assess the warhead's results. 

Via, click for source

It was this last project where I began to find answers. In the above picture taken by the TV-1 capsule (a Chrysler modified Jupiter nosecone) there seemed a possible shadow corresponding to the position of the mystery component at the 1 o'clock position. I thought maybe the mystery component could be related to the ejection of the TV-1 capsule as the serial numbers on the aft unit at the Cosmosphere (CC-2025/CC-2035) were close to some of the serials used in the project. Perhaps it was part of the equipment holding the capsule or commanding its ejection. Unfortunately a video from the project revealed that not to be the case, as the cradle design was not at all present on the artifact and the booster in that video lacked the mystery component:

However, a second video of the project did show the mystery component. More sightings followed: the boosters used in the Hardtack nuclear tests, pre-Block I boosters testing in Cape Canaveral and White Sands, and tests of late tactical boosters.

Given the component's absence on tactical boosters but presence in situations where measurements on their performance were germane and the co-axial-looking plugs, I began to suspect it was an antenna. Since it appeared in multiple projects, I assume the antenna was not payload specific but was for telemetry or tracking.

The unusually solid design left some question in my mind if the mystery component indeed was an antenna, so I sought verification on the forums of Antenna-Theory. The admin there, in two helpful posts, confirmed that it was probably an "Inverted 'F' Antenna" (IFA) or "Planar Inverted 'F' Antenna" (PIFA) operating in the UHF range at ~300MHz. These helpful specifics helped produce literature on tracking and telemetry systems used in the period.

Some systems could be ruled out because a second look at the body unit revealed there were plates appropriate for mounting the mystery component located every 90 degrees versus the 120 degrees mentioned in conjunction with certain systems. It also revealed a third cable leading into the pressurized compartment, presumably providing a hook-up to the ST-80 guidance platform.

The hanging plug and attached wire (nearly behind plug and disappearing into bulkhead) probably to connect the ST-80 or other instrumentation and the telemeter.

Thus, I believe the "mystery components" are telemetry/tracking antennas, given their uniform appearance on non-tactical and testing. The telemeter was probably an AN/DKT-2 (originally used on captured V2/A4) or AN/DKT-3. One source lists the AN/DKT-8 just as "used by Army," but the AN/DKT-8 is referenced in another as the XO-2.

From "Waveform Distortion in an FM/FM Transmitter System" by Simpson, Richard S., Ronald C. Houts, and Fred D. Parsons, p10.

A third reference lists the Redstone's telemeter as the XO-1, meaning its designation is probably less than 8. It is not a visual match to either the AN/DKT-7 or AN/DKT-5:

Screen Shot 2017-09-19 at 10.45.37 PM.png
Saturn I Recovery.png

However, a Bendix ad for the AN/DKT-3 shows only a close match (with the long "telemetering case with sub carrier oscillators"):

Screen Shot 2017-09-19 at 10.45.17 PM.png

So if the antennas and plugs were attached to a period telemeter, the AN/DKT-2 seems most likely. However, a tracking system is an even better candidate for being attached, as the Saturn I and Mercury-Redstone telemeters and antennas seem to be internal to those rockets while other documents show or indicate tracking antennas to be external.

The document "The Evolution of Electronic Tracking, Optical, Telemetry, and Command Systems at the Kennedy Space Center" provided a helpful grid summarizing the tracking systems used at KSC and which rockets they were used with. This allowed the construction of the following visual comparison:

This leaves the mystery component visible on the central booster to be the Beat-Beat DOVAP (Beat-Beat Dopplar Velocity And Position) antenna, a system for tracking the booster's deviation from its projected course. I believe this is a plausible definition on several points:

  1. Beat-Beat DOVAP would not have been used on tactical missiles as those would not employ post-launch tracking, hence why they were not on the missiles Mr. Ryan handled.
  2. Beat-Beat DOVAP was used on multiple types of missions with multiple types of payloads, hence why the component can be seen on pictures of different launches/types of launches.
  3. However, Beat-Beat DOVAP used a 36MHz frequency, which is an unexplained anomaly with what the said I should expect.