Below I've assembled some research into the question of which launch is actually the first to carry two satellites into orbit, but so far I think the results are inconclusive. So despite there being discussion of this in other posts, I think this issue of history and records in Space Exploration still needs its own, definitive answer.
Question: What is the first time that two satellites were launched together as the same payload?
The first launch that I could find it is this:
- Transit 2A
but maybe there are other launches before that?
Failed launches also count
- similar but not specifically a duplicate- History of multiple-payload launches?
- Highest number of satellites launched on a single rocket