The orbits of these satellites carries them within a few degrees of the Earth's poles, and they complete around 15 orbits a day (approximately one every 100 minutes). The satellite measures a swath of the earth's surface below it as it travels. Due to the relatively low orbit of these satellites, data is usually of high spatial resolution.
However, the temporal resolution of these satellites is dependent on their orbit and sensor characteristics. Satellites such as Envisat have a 35 day repeat cycle - the time taken to re-visit the same spot above the earth's surface. The time taken to make a repeat measurement at a point on the earth's surface may be significantly reduced if the instrument has a wide swath width, or the point is at high latitude, where the orbit tracks are closer together.