Evidence Latency
Evidence Latency
I'm a casual space enthusiast, so forgive me if this is ignorant, but is it typical that there is a delay (of several days or more) between hearing news about the success of a given space project and then the photos of it being published? I feel like I've noticed it a few times... And if so, why? Are photos hard/slow to transmit or make?
It depends on what the photos are. Something like photos of a launch, are usually pretty quick, the camera is on the planet.
However if we're talking photos from say the surface of Mars, that will take a while. The bandwidth is very limited, something like 8bps if I remember correctly. So it takes hours to download each image, and then you have processing of the raw image data for whatever they're trying to show.
There are some new transmission systems being deployed like the Deep Space Optical Communications (DSOC), and TeraByte InfraRed Delivery (TBIRD), but current vehicles can't utilize that, and the old Neep Space Network was built in the 1960s.
When New Horizons flew past Pluto, it took about 1 hour for the probe to send one image, and about 4 hours for the bits to travel from the probe to Earth. I believe those images were 1024x1024, so not very large.
Everything we end up with published by NASA and such are composites of many individual images that had to be downloaded very slowly.