malfunctions and a backpack. Watney crashes his helmet during the explosion of the Hab, but it is replaced by another Ares III helmet (during the rest of the period of Mars) and an Ares IV helmet (during the spaceflight). Hermes/Ares IV spacesuit Used by the Hermes crew and projected also for the Ares IV one, is a specialized spacesuit used during the Mars-Earth and Earth-Mars spaceflights on NASA's Hermes spacecraft. Commander Melissa Lewis also uses a Manned Maneuvering Unit (MMU) during the film's end. Ares V spacesuit Used by Rick Martinez and the other Ares V astronauts during the end credits of the film, is another suit, seen only during the launch of the Ares V mission. Skintight spacesuits The potential for greater mobility and simpler operation with a skintight spacesuit, generally referred to as a space activity suit or mechanical counterpressure suit, make this type of space suit an attractive choice for fiction, where flexibility of use can be a boon to plot development. Some space story writers whose work mentions flexible skin-tight spacesuits include: The spacesuits in early Buck Rogers comics seem to be skintight. Jerry Pournelle, who has been extensively involved in analysis and design of space technology systems. Pournelle envisions a layered design where the inner flexible suit can be overlain with various kinds of thermal protection or armor, for protection against meteoroids or space battle damage, in the same way a flak jacket protects the occupants of a warplane. Skintight spacesuits first appeared in recent science fiction in Pournelle's novel Exiles To Glory in 1977. A. Bertram Chandler. Grant Callin's Saturnalia and A Lion on Tharthee feature 'micropore suits' which use minute gas bubbles in foam rather than mechanical tension to provide counterpressure in vacuum. Stephen Baxter's Manifold Trilogy, notably Manifold: Time, covers the technical aspects of using a skintight suit for short EVAs, including the need to don the suit without creasing to prevent embolisms. In Larry Niven's Known Space, skintights are the preferred type of spacesuit used by belters in the 22nd and 23rd century. They often decorated them with elaborate (and expensive) torso paintings as a form of heraldry. Pournelle's design in particular is featured in some of Niven's later Ringworld novels. Victor Koman in Kings of the High Frontier. Kim Stanley Robinson used suits called "Walkers" that work on a similar principle for Martian surface exploration in the Mars Trilogy novels.