The memory cubes unlock the memories (lore) of the former captain of the Bumbling Bee in your personal bot. Very fragmented, out of order, and it doesn't seem complete. No matter how many updates the game has, there always seems to be one more memory cube than you can use for that.
The non-glowing version of that first cube are mystery cubes, used to unlock certain precursor technology. I've been puzzling out the glowing version of the mystery cubes (forget what they're called, and don't have any in stock in my latest save), too. They're fairly new items, but aren't documented in the walkthrough and I haven't seen much talk about them, here.
I did once find I had used up several upgrading... SOMETHING in bot construction, but by the time I realized I was doing that I'd used them all up, and hadn't realized that was what I was doing (I'd thought I was dismantling the bot parts in question to free up space, not upgrading them). Haven't had a chance to figure it out, since, and I have no idea if they're involved in anything other than that.