I'm working on the assumption that a "proper" ship like Semaphore's is capable of much faster speeds than the... uh... thing... Major Tom and Isaac are on (which is only sub-light speed).

How does "convenient catch-up speed" work? Simple: it calculates the optimum speed from the speed and trajectory data provided by the tracking device on the ship you are following.

Panel 1: Semaphore is flying the ship that formerly belonged to Major Tom and Isaac.

Caption:

On the way to Space Station Clarke

Semaphore:

Hmm, those two Agency guys left a good couple of hours before me, I need to go faster.

Let's see what speed settings this ship has.

"Exhilarating" is probably not quick enough and "Ludicrous speed" will get me there far too soon; ahh, this looks like the perfect setting…

Panel 2: Major Tom's ship distorts as it speeds up.

VFX:

CONVENIENT CATCH-UP SPEED!

SFX:

Fwooooshhh!

Panel 3: Semaphore has slowed down again as he approaches Space Station Clarke. Between Semaphore and the station is Major Tom and Isaac's ship.

Semaphore:

Aha! I've conveniently caught-up with them!

Planting a tracking device on their ship was definitely one of my better ideas.

{{Sigh}} Semaphore, you need a holiday, you're talking aloud to yourself again, it's weird!