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Phys.org's Europa Clipper high-gain antenna undergoes testing says:

The full-scale prototype antenna, which at 10 feet (3 meters) tall is the same height as a standard basketball hoop, is in the Experimental Test Range (ETR) at NASA's Langley Research Center in Hampton, Virginia. Researchers from NASA's Jet Propulsion Laboratory in Pasadena, California, the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, and Langley are testing the prototype in the ETR in order to assess its performance and demonstrate the high pointing accuracies required for the Europa Clipper mission.

The ETR is an indoor electromagnetic test facility that allows researchers to characterize transmitters, receivers, antennas and other electromagnetic components and subsystems in a scientifically controlled environment.

It uses the image described in JPL's Space Image page Europa Clipper Antenna Prototype shown below.

You can also see it in Engadget's NASA is testing Jupiter moon probe's data-beaming antenna

Notice that there is a projection screen with an image of Jupiter and presumably Europa being projected on to it.

Kudos for "keeping an eye on the prize" but I am not sure how the projections could be part of the testing of the antenna. Perhaps the image is there to improve the attractiveness of the photo-op for publication, but that wouldn't explain the presence of the screen or the rojector.

Question: How is this video projection screen is used in tests of Europa Clipper's high gain antenna? Are there optical tests of imagers or star cameras done in this site as well perhaps?

Europa Clipper High Gain Antenna testing

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    $\begingroup$ Two random theories. This screen might be used to give some hint as to where the antenna is meant to be in relation to the Jupiter / Europa system: it's the 'view from the spacecraft for this test' perhaps (but how often do you actually get a convenient alignment like that in a real orbit?). Or this screen normally shows data and this is the screen saver. Or more likely as you suggest it's just pretty for the photograph, and could even have been put there just for the photograph: perhaps the most likely. No evidence for any of these. $\endgroup$
    – user21103
    Mar 7 at 11:11
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    $\begingroup$ @tfb Hmm... if so, then to give some hint or show... to whom? Is it a cue for the engineers setting up the test, or for some camera on the spacecraft, or for the viewers of this photograph, or for visiting dignitaries (like the "don't' touch" sign)? $\endgroup$
    – uhoh
    Mar 7 at 11:51
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    $\begingroup$ yes my initial idea was that it might be to give a visual clue about where it was in the orbit to engineers positioning things. But that's just wrong I think: I presume that the antenna always points more-or-less the same way (because the thing that is testing it is in that direction), but obviously in an orbit that would mean that Jupiter could be in any direction, not where a screen happened to be. I think it's just for the photo. $\endgroup$
    – user21103
    Mar 7 at 18:14
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    $\begingroup$ @tfb I think you are right, and for passing dignitaries on tours perhaps. $\endgroup$
    – uhoh
    Mar 7 at 22:39

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