Ryujin
Legend
Voyager at 18 billion km away is easily visible from the background while only generating a 20 watt radio signal with a radio telescope. I can imagine how a ship generating terawatts in thrust would stand out. As far as I understand it, there's no easy or fast way to get rid of the heat you generate in space.
Somewhat easier when you know precisely which cubic inch of sand you need to look at in the first place.