Mariner was a 10-mission NASA program which sent unmanned probes to Mars, Venus, and Mercury from 1962 to 1973. Mariner 4 sent us the very 1st close-up pictures of Mars, and Mariner 10 send us the 1st pictures of Mercury & Venus.
Have you ever wondered how we got pictures back from unmanned spacecraft in the early 60s, when we barely even had color TV, let alone digital cameras? We used television cameras with vacuum tubes called “vidicons.” They looked a lot like Kuiper’s vacuum tubes here, but longer, and they had a flattened top. The TV cameras created an analog image like on an old school black and white television.
Here’s how it worked for Mariner 4: Mars is too far away for us to receive a clean enough analog signal to avoid making our TV all static-y. Thus, we had to take the analog picture from the TV camera and digitize it. The onboard digitizer sliced up the analog information into 200×200 “pixels” and assigned each pixel a number from 0 to 63 depending on how bright or dark it was. Then Mariner transmitted the numbers back to Earth.
There’s always going to be some amount of interference, changing the data slightly over such a long distance. Making the signal digital gave us a greater margin of error. It basically allowed us to say “ok, the signal says this square is .2, so it’s probably really 0” or “this square says 48.7 so let’s call it 49.”
In 1965, when the Mariner engineers at NASA received the data for the first ever picture of Mars, they were VERY. EXCITED. Their computer wouldn’t be done reconstructing it back into a picture til the next day, and they didn’t want to wait. Instead, they printed out the numbers onto strips of paper, stapled them to a cubicle wall, and colored them by hand with pastels from a local art store.
When they were done, the engineers did what any good engineer would do: they took a saw to the wall, framed it and gave it to their boss.
Original post: https://www.instagram.com/p/BdrRjXgg6n2/