I like to think hard about science fiction tropes and how accurate they are to the real world. Today, let’s look at my favorite mecha anime metaseries, Mobile Suit Gundam! Just how hard would it be to fight in space using a giant robot? From Reddit’s r/Gundam:

Theoretically, how hard would it be to pilot an MS (Without any space magic) and in which universe would it be the easiest to pilot an MS?

Let’s assume we’re in the Universal Century, Gundam’s main timeline. In it, “Minovsky particle interference” forces a return to visual-range combat and unguided weapons. That, combined with a multi-limbed robot’s ability to balance, maneuver, aim, and grapple are supposed to justify the use of giant mecha as the mainstay weapons in space warfare.

Combat in space relies on knowing an enemy’s relative position in three dimensions, heading, and relative speed.

Heat signatures would show up, but that would only provide two dimensions of position, so you need more information. Compounding difficulty is the lack of landmarks able to be used to establish relative positions. There’s nothing out there to establish scale, You can fudge a guess at distance if you know the exact size of the ship and its apparent size, but again, heading and speed would be extremely difficult to calculate without instruments. Dazzle camouflage would make it extremely difficult to line up a successful shot. And if you’re heading towards each other instead of trying to get your orbits to intersect, your relative speeds will be so fast you’ll have milliseconds to aim and fire.

It would be so hard to calculate a shot on the fly that combat in space is impractical at best without the aid of guided weapons and sensors, that it’s not worth attempting unless there’s no other choice.

Now, throwing mass at targets large enough (say, a city or a space colony) with a known position and heading (say, a LaGrange point or the bottom of a gravity well), at high enough relative speed, and you can make that F = ma accurate enough to matter. Colony drops or ballistic strikes on space colonies would work, so there’d have to be some kind of detente or peace agreement in place to avoid mutual catastrophe.

That went a bit astray of the initial question and relies heavily on Robert A. Heinlein’s The Moon Is a Harsh Mistress and Citizen of the Galaxy, but hopefully it makes sense. Enjoy the rest of your day, and suit up!