For example, development of a 70 mm magazine was accelerated to meet the space program. The first modified (in fact simplified) Hasselblad 500 C cameras were used on the last two Project Mercury missions in 1962 and 1963. They continued to be used throughout the Gemini spaceflights in 1965 and 1966. A general program of reliability and safety was implemented following the Apollo 1 fire in 1967, addressing such issues as reliability and safe operation of electrical equipment in a high-oxygen environment. EL electric cameras were used for the first time on Apollo 8. A heavily modified 500 EL, the so-called Hasselblad Electric Camera (HEC) was used from Apollo 8 on board the spacecraft. Three 500 EL cameras were carried on Apollo 11. An even more extensively modified Hasselblad EL Data Camera (HDC), equipped with a special Zeiss 5.6/60 mm Biogon lens and film magazines for 150–200 exposures, was used on the Moon surface on the Apollo 11 mission. This command module camera, carried on Apollo 11, was a simplified version of the commercial Hasselblad 500 EL motorized film advance camera. Used for color still photography, it could operate in the command module or in the vacuum of space. All following NASA missions also had Hasselblad cameras on board. The photographic equipment and films used on the five subsequent flights were similar to that taken on Apollo 11. On Apollo 15, the 500 mm telelens was added. During the Space Shuttle period cameras based on the 500 EL/M, 553 ELX, 205 TCC and 203 FE have been used. There are 12 Hasselblad cameras currently sitting on the lunar surface, where only the film magazines were brought back to Earth. The HK-7 put a 7 cm tall by 9 cm wide image on 80 mm film. It has interchangeable lenses, generally a 135 mm Zeiss Biotessar, with the second being either a 240 mm f/4 Meyer Tele-Megor or a 250 mm f/5 Schneider Tele-Xenar. The SKa4 has interchangeable film magazines, a key feature of later Hasselblad cameras. Hasselblad's first civilian camera was launched in 1948. Born from the idea of Victor Hasselblad to create the "ideal camera", it was a 6×6 cm format focal-plane shutter SLR camera that was six inches long. First simply known as the "Hasselblad Camera" it was later named "1600F" after its highest shutter speed of 1/1600 sec and "F" for "focal plane".