to destroy a starship, though firing it requires vast amounts of energy which can quickly drain the SPHA-T. Joe Pappalardo of Popular Mechanics has criticized the design of the SPHA for using legs compared to wheels or treads which would be easier to maintain. Single Trooper Aerial Platform (STAP) STAPs, which first appeared in The Phantom Menace and have featured in other Star Wars media, are designed to appear reminiscent of the speeder bikes seen in Return of the Jedi. The STAP's design also relates back to Lucas' 1973 idea of ridable "jet-sticks" which appeared in early drafts of the original Star Wars movie. A draft of The Phantom Menace refers to the vehicles as STAPS, or Single Troop Armed Pogo Sticks. These lightweight reconnaissance vehicles are based in-universe on civilian vehicles called airhooks, modified for greater performance and to be piloted by the Trade Federation's battle droids. Floating above the ground thanks to "repulsorlift" technology, a pair of drive turbines on either side of the vertical stem gives it impressive speed and maneuverability. Though armed with a pair of blaster cannons, the STAP leaves its pilot completely exposed, making it ill-suit for heavy battle. Swamp speeder Swamp speeders appear in Revenge of the Sith during battle scenes on Felucia and Kashyyyk. TJ Frame, who worked on the swamp speeder concept soon after joining the art department, initially designed the craft to be appear reminiscent of fanboats. Within the Star Wars universe these vehicles are known as Infantry Support Platform (ISP) speeders, built for the Republic during the Clone Wars by Uulshos Manufacturing. ISPs use repulsorlifts and a powerful turbofan to patrol swampy regions, leading to their nickname, although they can be used on almost any terrain. Operated by two clone troopers and armed with a pair of twin swiveling blaster cannons, the ISP can move at speeds of up to . Wheel bike General Grievous rides a wheel bike in Revenge of the Sith during his confrontation with Obi-Wan Kenobi (Ewan McGregor). Grievous' vehicle is similar to another wheel bike that appears in the Star Wars: Droids cartoon. One concept for Grievous' vehicle was for it to include "tank-like chariots"; at another point, the vehicle was going to be another droid. Grievous' wheel bike is identified in Star Wars source material as a TSMEU-6 personal wheel bike built by the Z-Gomot Ternbuell Guppat Corporation. Wheel bikes are described as