Meteor 3-5, launched in 1991, is in a slightly higher orbit than Meteor 2-21, and operated until 1994. It transmitted on 137.300 MHz. Mechanically, it is similar to Meteor 2-21. Which satellite was in operation depended on the sun angles and consequently the seasons. Meteor 3-5 was usually the (Northern Hemisphere) "summer" satellite while 2-21 was in operation for approximately the half-year centered on winter.