OneDumbG0
Find Your Own Fire
^ The Thanagarians slowed the moon down. That much is clear. From my reading, the Sunstone created a near-relativistic bubble around it. And while the original Kryptonian ship provided its propulsion, the Sunstone crystals also controlled the speed.
The way I had read it was that the bubble created a kind of tactile kinesis field around it (a power that allows the application of strength against an object and prevent it from crumbling). Like... if you actually tried to drag a moon away from Jupiter in real life, no mater how strong that ship was, that moon would fall apart and crumble through pure gravity from Jupiter. In this way, by creating a near-relativistic bubble around it, it nullified normal gravitational effects allowing the propulsion ship to drag it through space. And as such, it also likely interfered with Superman and his regiment's application of pure strength on it while the bubble existed.
Rage.Of.Olympus is right in one sense though, from my reading, the Thanagarians pretty much eroded the relativistic bubble and slowed it down substantially and it still did take all of New Krypton to arrest its movement and place it into orbit. However, you could argue it took all of New Krypton because the relativistic bubble was gone and a few Kryptonians trying to arrest its propulsion would have simply punched through the moon.
But in that case then... it appears that for whatever reason, Superman or the Kryptonians didn't have tactile kinesis. Which is kind of weird. Also, there's a very simple explanation for why they had masks on, so that they could talk to each other. Sound doesn't travel in space and if you had a recorder next to your mouth in space without any gas as a medium for sound to travel through, the recorder would be useless.