There's a little more detail about the Apollo situation on a post [1] by Neal Strickberger on Candlepower Forum:

"Chicken wire! Turns out this was added for the Apollo program, when they used the TVS-3s to light the pad. A 20kW short-arc fed with 400Hz 3phase fullwave rectified unfiltered power produces lots of RFI at 1200Hz harmonics, and when nice and focused with a reflector it was enough to shut down the capsule. So they made a Faraday cage."

[1] https://www.candlepowerforums.com/vb/showthread.php?348441-A...