From Tekkenpedia

Final Frontier
Walls	Yes
BG Music	Orbital Move

Final Frontier is a stage in Tekken 5. It is a gigantic glass spaceship that is located in space. This place has a glass floor. If you look to your left or your right, you will see Pac-Man, along with the words, "Welcome to the Final Frontier!!". Pac-Man is another game that is made by Namco. Among the many things that can be seen in this area are the moon, Earth, stars, a black sky, large metal rotating bars with green lights at the end of them, and four huge yellow rotating wheels that look like huge hubcaps.

[edit] Trivia

• Lee and Heihachi both have their Round 4 battles against their sub-bosses in this stage.
• The stage's name is a reference to its location (outer space).