Most likely trajectory of the Gravity Probe A spacecraft, and location of the microwave maser receiver on Earth?

Question

Background/motivation

@PM2Ring's comment under an answer to "Is there a wavelength shift between sunlight observed from the ISS versus from Earth's surface?" in Physics SE links to the alludes to the Pound–Rebka experiment where the measurement of the blue/red shift of photons in a gravity gradient was proposed¹. It was confirmed the same year (1960)² using gamma rays and the incredibly sensitive Mössbauer effect and a modest height difference of about 22.5 meters on Earth.

A further test of the same type, the gravitational blue-shift of a microwave signal sent from space to Earth's surface was performed in 1976 using the satellite Gravity Probe A which was equipped with a 1 part in 10¹⁵ frequency stabilized microwave maser. It's signal was received on Earth and compared to an (essentially) identical maser on the ground via heterodyning and measuring the 4 parts in 10¹⁰ difference in their frequencies.

Research effort

The linked Wikipedia article mentions that Cospar ID "GRAVR-A" was a Scout sounding rocket launched from Wallops, with an apoapsis of "10,224 km". (There's always that ambiguity if that's really referenced from Earth's center, or it's equatorial radius 6328 km) It links to https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=GRAVR-A with the following information:

NSSDCA ID: GRAVR-A

Launch Information Launch Date/Time: 1976-06-17T00:00:00Z Launch Vehicle: Scout Launch Site: Wallops Island, United States Decay Date: 1976-06-17

Trajectory Description: No description available.

Trajectory Details

Type: Orbiter Central Body: Earth Epoch start (UTC): 1976-06-17 00:00:00 Epoch stop (UTC): (blank) Orbital Parameters

Periapsis	Apoapsis	Period	Inclination	Eccentricity
0.10 km	10224.00 km	(blank)	35.000°	0.44471

Regions Traversed: (blank)

Question:

What is the most likely trajectory of the Gravity Probe A spacecraft and where was the experiment's receiver on Earth, based on all information available? For example:

1. It was launched from Wallops but how far downrange did it return to Earth?
2. In unambiguous terms, what was its apoapsis and periapsis measured from the center of the Earth? How high did it reach above Earth's surface? These can be estimated - don't worry about a few hundred km, it's that 6378 km ambiguity that's bothering me
3. Where was the microwave receiver on Earth? Was it at Wallops, or closer to directly under the maximum height where the the shift would have been the most steady?

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References:

• ¹Apparent Weight of Photons R. V. Pound and G. A. Rebka, Jr. (1960)
• ²Measurement of the Gravitational Red Shift Using the Mössbauer Effect in Fe⁵⁷ T. E. Cranshaw, J. P. Schiffer, and A. B. Whitehead (1960)

Answer 1

Partial answer due to incompletely reproduced reference :(

It was launched from Wallops but how far downrange did it return to Earth?

A map of the groundtrack is shown.

How high did it reach above Earth's surface?

NON-ANSWER

Every other page in the document is missing - it appears that they didn't bother to scan the back sides of the pages sigh - so a lot of info is missing. Here's a sketch of the trajectory without any numbers. They talk about how precise the trajectory tracking was...

Where was the microwave receiver on Earth? Was it at Wallops, or closer to directly under the maximum height where the the shift would have been the most steady?

There were 3 earth based masers, one at Wallops and two at Merritt Island (MILA) in Florida. The ones at MILA appear to have been the primary ones used in the experiment:

The frequency of signals from the oscillator was monitored on the ground at Merritt Island, Florida by using two hydrogen masers as comparison oscillators.

The crucial page 6 is missing, but from reading what remains, it appears all the ground equipment used during the actual flight was at MILA. The second MILA maser was "set up to monitor the primary reference".

Reference: A test of the equivalence principle using a space-borne clock