An improved version of the Zenit 4, the Zenit 4M carried a new camera, solar panels, and a restartable engine so the satellite's orbit could be altered during the course of its mission. The mission duration was 13 days.

2023年1月14日 · The soviet Zenit-4M (Rotor, 11F691) was an improved version of the Zenit-4 high resolution reconnaissance satellite and was part of the Vostok-based Zenit-family. The satellites consisted of the Vostok-based service and reentry modules.

The Zenit-4M was the first of the series equipped with a restartable engine which allowed adjustment of the orbit during the mission. High resolution, maneuverable; Typical orbital profile: inclination 65 degrees with altitude of 203-290 km; maneuvers to 178-312 km altitude.

2014年10月20日 · The Zenit-4M was an improvement over its predecessors by adding an Isayev orbit adjust engine atop the sphere, enabling it to boost its orbit and extend its lifetime, and making its appearance even uglier than earlier versions.

天顶4M-1 Kosmos 251 (Zenit-4M 1 Rotor 1) 国籍: 苏联: 研发机构: 进步火箭航天中心: 任务类型: 测绘（拍照） 轨道高度: 193 km×164 km

2023年1月14日 · The Zenit-4MKM, also known as Gerakl or 11F692M, was a soviet optical high resolution reconnaissance satellite of the Vostok-based Zenit-family to replace the earlier Zenit-4MK (Germes). The satellites consisted of the Vostok-based service and reentry modules and featured an additional maneuvering engine, which was jettisoned before reentry.

1972年4月14日 · The soviet Zenit-4M (Rotor, 11F691) was an improved version of the Zenit-4 high resolution reconnaissance satellite and was part of the Vostok-based Zenit-family. 43/3 (43L) has witnessed the launch of 229 rockets, including 229 orbital launch attempts, while Plesetsk Cosmodrome, Russian Federation, has been the site for 1669 rocket launches.

2019年11月9日 · Second generation imaging satellite equipped with film cameras for photo-reconnaissance and an orbit adjustment motor. First Zenit-4M to be detected at the secondary transmission frequency - 19.300 MHz. The cameras and film were recovered from orbit.

Low-perigee reconnaissance satellites - Zenit-4M (Rotor) This sketch of a Soviet reconnaissance satellite is indeed baffling. There are several large groups of reconnaissance satellites with perigees around 170 km. Occcasionally lower perigees were used, but very seldom.

2019年11月9日 · Zenit-4 It was originally designated Vostok-4 but the name was changed to differentiate it from the piloted spacecraft. One mission is specifically of note - Cosmos 309 (1969-098A/4223) was the only Zenit-2 to carry a Nauka module, a …