The Missing Sets
Under the Lego Mars Mission theme, there are two sets that were never officially sold or released, but still appear in the customer service listings. It appears that they were either early prototypes for what later became actual sets (or part of actual sets), or were simply planned for and never officially released. It is likely that these sets were not releases because the theme already had two (eventually three) "impulse" sets, and the theme would be unbalanced with an additional two.7728: Jet Pack
This set was never officially released, but a very similar model was included as a part of the MB-01 Eagle Command Base. The set itself features an Astro Pilot minifigure and contains 25 parts (with torso and legs assembled). The completed set and parts list for the Jet Pack can be seen at https://brickset.com/sets/7728-1/Jet-Pack. Below is a page of instructions made by rennatnave101 which shows the assembly of the Jet Pack without the minifigure. Also below are the instructions for the jet pack model included in the MB-01 Eagle Command Base set, to show the similarity between the two. It is entirely possible that the Jet Pack set was a prototype for the jet pack model, which, with the addition of the round plate, is a sturdier construction.
Instructions for 7728 Jet Pack set, made by rennatnave101 |
Instructions for jet pack model from MB-01 Eagle Command Base booklet |
7729: Alien Flyer
The alien flyer was never released as part of a set, and nothing really appears to be modeled after it. That being said, it is the fundamental equivalent to the actual set, "Alien Jet," and does follow the overall design theme of the Alien faction with its curved wings. The set had 21 parts and included one alien minifigure. The complete set and parts list for the Alien Flyer can be found at https://brickset.com/sets/7729-1/Alien-Flyer. Below is a page of instructions made by rennatnave101 which shows the assembly of the Alien Flyer without the alien minifigure.
The alien flyer was never released as part of a set, and nothing really appears to be modeled after it. That being said, it is the fundamental equivalent to the actual set, "Alien Jet," and does follow the overall design theme of the Alien faction with its curved wings. The set had 21 parts and included one alien minifigure. The complete set and parts list for the Alien Flyer can be found at https://brickset.com/sets/7729-1/Alien-Flyer. Below is a page of instructions made by rennatnave101 which shows the assembly of the Alien Flyer without the alien minifigure.
Instructions for 7729 Alien Flyer set, made by rennatnave101  |