From the 1960s, most US television drama series started each episode by launching directly into the story, before showing the series title sequence. This short sequence was called the "hook", "teaser" or "cold open". It was rare in the UK, to the extent that US shows like Star Trek were edited to shift the series titles to the start of the episode. Lew Grade's ITC series were sold to US stations, and unusually for British television they followed the US convention of the "hook".
All episodes of Space: 1999 were written with a "hook" preceding the "standard series opening". In the US, this would be followed by a commercial break, before the first act began, showing the episode title and in-show credits. The series titles recap the Moon being blown out of orbit, which is a climax of this first episode, so it was logical to do something different. The first script of "The Void Ahead" by George Bellak describes the series titles over establishing shots of the Moonbase Alpha and the Moonbase sets, as the story continues.
The set we know as Main Mission was originally called "Central Control" ("Main Mission" was the organisational section, not the room). Leading the section is Vorkonen, who would later become Paul Morrow. The outgoing commander is Grodno, later to be renamed Gorski (both names are Polish; although the modern city of Grodno is in Belarus, it was historically Polish).
14 EXT. SPACE SKY. SFX. 14
Foreground Moon in relation to Earth.
15 EXT. MOONBASE ALPHA. SFX. 15
OPENING ON A HIGH WIDE SHOT OF THIS extraordinary Base
complex and moving in slowly, inexorably to the landing
pad area. TITLES START... Now, we reach the Central
Control exterior and...
CUT TO:
16 INT. CENTRAL CONTROL. 16
Great excitement and hubbub here, a sense of tension,
apprehension among the six permanent Main Mission
operatives.
Here also are as many of the hierarchy of Alpha who
are able to leave their posts to greet a new Commander
CAMERA TRACES PAST THEM
They talk, excitedly, in small groups.
ON VORKONEN
A high rank on Main Mission staff, forceful-looking,
young...
ON GRODNO.
Approaching middle age, tense and worried-looking. He
is the outgoing Commander and he wears the distinctive
uniform with two black sleeves.
ANOTHER ANGLE
As Grodno checks the time on his commlock and nods.
He moves to the door. The others surge to follow.
There is sound behind all this but no dialogue that
we need to hear.
17 INT. MTU PASSENGER MODULE 17
Commander John Koenig is here, uniformed as Grodno.
He sits watching a video screen set into the back of
the seats in front of him. Beside him is a Main
Mission aide, also watching.
AND NOW MAIN TITLES FADE
John Koenig is perhaps forty - intense, intelligent,
and somewhat preoccupied now as he watches the screen
and listens to the Earth News Report.