[2] Doctor Helena Russell is typing a report on a World Space Commission Medical Department form regarding the status of astronaut Captain Tony Cellini.

The Ultra Probe departed from the Interplanetary Space Station on its seven-month journey, with Cellini and three other crewmembers; Darwin King, Juliet Mackie and Monique Bouchere.

Emitting a deafening electronic scream, a huge, tentacled creature with one blazing eye and a fiery maw materialised in the probe ship.

When the conversation turned to the Ultra Probe incident, he became physically and verbally agitated, and Helena was forced to order sedation as the hysterical Cellini pleaded with her to believe him.

Stating there was no evidence on the flight recorder of any 'monster', he judged that Cellini bungled the decompression procedure, killed his crew and refused to accept the blame.

In September 1999, Koenig was appointed base commander to resolve the Meta Probe crisis, and he transferred his friend Cellini back to Alpha's Reconnaissance Section.

After the Moon's breakaway, all memory of the Ultra Probe incident was obliterated by their struggle to survive in a hostile universe—until Cellini's irrational behaviour on this night revived the controversy.

He tells Koenig and Helena that his attempt to depart Alpha was in response to an unconscious feeling that the Ultra Probe monster was near and he needed to go out and face it.

Taking a knife, a fire axe and rope, he enters the eerie darkness of main module and secures his lifeline to a support girder.

In addition to the regular Barry Gray score (drawn primarily from "Matter of Life and Death" and "Another Time, Another Place"), Remo Giazotto's composition ‘Adagio in G Minor for Strings and Organ in G Minor’ is played over the flight sequences of the Ultra Probe[3] and the 'space horror music' composed by Vic Elms and Alan Willis for "Ring Around the Moon" is used during the encounters with the monster.

[4] Reports indicate that Martin Landau (always cautious of his male castmates—especially Tate—receiving any significant exposure) influenced the production staff to rewrite the part as a one-off guest role.

In the final shooting script dated 21 January 1975, the Tony Cellini character is named 'Jim Calder' and Doctor Monique Bouchere is 'Olga Vishenskaya'.

This draft contains no reference to Koenig, Bergman and Dixon mentioning evidence about the spaceship graveyard or the Ultra Probe's docking with the alien ship apart from the scanner contacts and Cellini's testimony.

This dialogue must have been part of the last-minute script amendments: in the final cut, it seems a little odd that Dixon says they have only a series of unidentifiable bleeps on the scanner, but then Koenig states that the black box recorded a tight docking seal and a breathable atmosphere inside the alien spaceship.

Reports indicated that the visual effects crew shot a sequence including Star Trek's USS Enterprise and Doctor Who's TARDIS, but the footage was never used.

The orange versions of the jacket seen on Koenig and Cellini would be worn next episode by Security personnel and later, in series two, by Maya and a variety of guest artists.

The computer banks seen in the main module of the Ultra Probe ship originated in SHADO Control from the Andersons' previous science-fiction series UFO.

[7] John Kenneth Muir comments that besides Saint George and the Dragon, the story evokes Homer's Odyssey and the 19th-century novels Moby-Dick and Twenty Thousand Leagues Under the Seas in its portrayal of Cellini's quest to destroy the monster.