The Apollo program used several television cameras in its space missions in the late 1960s and 1970s; some of these Apollo TV cameras were also used on the later Skylab and Apollo–Soyuz Test Project missions. These cameras varied in design, with image quality improving significantly with each successive model. Two companies made these various camera systems: RCA and Westinghouse. Originally, these slow-scan television (SSTV) cameras, running at 10 frames per second (fps), produced only black-and-white pictures and first flew on the Apollo 7 mission in October 1968. A color camera – using a field-sequential color system – flew on the Apollo 10 mission in May 1969, and every mission after that. The color camera ran at the North American standard 30 fps. The cameras all used image pickup tubes that were initially fragile, as one was irreparably damaged during the live broadcast of the Apollo 12 mission's first moonwalk. Starting with the Apollo 15 mission, a more robust, damage-resistant camera was used on the lunar surface. All of these cameras required signal processing back on Earth to make the frame rate and color encoding compatible with analog broadcast television standards. Starting with Apollo 7, a camera was carried on every Apollo command module (CM) except Apollo 9. For each lunar landing mission, a camera was also placed inside the Apollo Lunar Module (LM) descent stage's modularized equipment stowage assembly (MESA). Positioning the camera in the MESA made it possible to telecast the astronauts' first steps as they climbed down the LM's ladder at the start of a mission's first moonwalk/EVA. Afterwards, the camera would be detached from its mount in the MESA, mounted on a tripod and carried away from the LM to show the EVA's progress; or, mounted on a Lunar Roving Vehicle (LRV), where it could be remotely controlled from Mission Control on Earth. RCA command module TV camera Development NASA decided on initial specifications for TV on the Apollo command module (CM) in 1962. Both analog and digital transmission techniques were studied, but the early digital systems still used more bandwidth than an analog approach: 20 MHz for the digital system, compared to 500 kHz for the analog system. The video standard for the Block I CM meant that the analog video standard for early Apollo missions was set as follows: monochrome signal, with 320 active scan lines, and progressively scanned at 10 frames per second (fps).