"Somewhat better" photos of the Chinese balloon payload

[Citysnaps]

Although far from a decent photo, one can still speculate a little about the balloon payload structure.

I'm guessing what is believed to be the four motor-driven propellers are used to orient the balloon and payload boom. I'm wondering if the boom can be rotated on its longitudinal axis to both keep the collection antennas, presumably on the backside of the boom behind the solar panels, oriented towards signals of interest on Earth. And from time-to-time to orient the solar panels towards the Sun to charge batteries. Perhaps the the four propellers can also make course changes (to some extent). Guessing the small white dish/disk at the boom's center is an antenna used to periodically upload collected signals data to a satellite for subsequent transmission, either real-time or stored/forwarded, to a ground station either back home, or at another location (the Chinese ground station recently constructed in Argentina, ostensibly for "peaceful space research") comes to mind. That datalink could also be used to send new signals collection tasking to the balloon's collection equipment.

It would be nice if higher resolution photos, of both sides of the boom, would eventually be released to the public. Perhaps that will be coming soon with different elements of the payload identified.

Our Best Look Yet At The Chinese Spy Balloon's Massive Payload

A just declassified high-resolution image of the Chinese spy balloon taken from a U-2 shows what appear to be propellers and other features.

www.thedrive.com

 

[Chew Toy McCoy]

I was shocked to discover that under the balloon there appears to be a basket-like structure with 2 occupants drinking wine. This is clearly an act of war.

 

[Yoused]

Guessing the small white dish/disk at the boom's center is an antenna used to periodically upload collected signals data to a satellite …

Your guess would almost certainly be incorrect. A dish aims a signal at its focal point, which is a very short distance away from it. Dishes are for collecting signals. Transmitters are more compact devices, often with radiator fins for shedding heat, designed to broadcast to a distant receiver (which itself will have a dish).

 

[Citysnaps]

Your guess would almost certainly be incorrect. A dish aims a signal at its focal point, which is a very short distance away from it. Dishes are for collecting signals. Transmitters are more compact devices, often with radiator fins for shedding heat, designed to broadcast to a distant receiver (which itself will have a dish).

Dish and other kinds of high gain/high directivity antennas can be used for both transmission and reception. They provide gain, directivity (via narrower beamwidth) as a function of diameter, over an ideal isotropic radiator (a point source radiating/receiving equally well in all directions).

Reciprocity holds for both transmission and reception, with respect to gain and beamwidth. The larger the reflector the more gain and the narrower the beamwidth becomes. The smaller the reflector, the wider the beamwidth, the less aiming precision is needed, with the downside of less antenna gain.

What appears to be a small dish antenna (the white disk) on the balloon payload would provide some gain (always desirable considering path-loss over long distances to a distant satellite), especially with limited transmitter power output, but likely a not-so-narrow radiation pattern - thus allowing positioning to not be as critical. The satellite it probably communicates with for uploading collected intelligence data and transmitting future balloon payload tasking, would have an antenna with gain and beam pattern that can be roughly position positioned - either mechanically or steered electronically by a beamformed array.

Datalinks, whether terrestrial or Earth <> satellite, frequently use dish, dish-like, or other directional antennas (such as a helical or crossed Yagi) - especially on the satellite end of the link. As dish antennas have a narrow beamwidth they of course need to be aimed at each other, and if either source is moving, need to track each other in azimuth/elevation. A satellite ground station with a larger dish (more gain to receive weaker signals from the balloon payload) and precise dynamic tracking positioning would keep the link working while the balloon/payload is moving.

Collection antennas on the balloon payload beam (presumably behind the payload beam), on the other hand usually have a wide beamwidth pattern (at the expense of less gain) since the goal is to collect or survey unknown signals of interest over a wider area. Or could use an electronically steered beamformed array of elements to provide directionality and gain to quickly survey an area on the ground. I haven't seen any photos of the back side of the payload boom where I'm guessing those antennas are located.