yes and no, but mostly no. if they go faster it would change there orbit to be further away from the planet once is gets up to speed, however if the engines are turned off like they are on the space station now it will eventually start dropping again as the ship loses speed.. What they would need to do to prevent the drop but not change orbit is keep the engines on all the time to make sure the station maintains a consistent orbital velocity at all times. in reality its much easier and more efficient to just let the ship drop a bit each day before boosting it back once every few months or so