This comment mentions:
This relation between drag and mass is taken to a relative (for satellites) extreme in GOCE which I think needed to be close to Earth to accurately sense the changes in gravity, but "streamlined" (have a low frontal surface area) to not decelerate too much in order to reach a mission duration of at least 20 months. Some called it "the Ferarri of Space" (Phys.org, 12-Sep-2013: 'Ferrari of space' set to fall to Earth)
And that Phys.org article says:
Circulation Explorer (GOCE) orbits at an extremely low altitude of just 260 kilometres (160 miles), where there are lingering molecules of atmosphere.
To reduce drag, it has an arrow-like octagonal shape and two fins to provide extra aerodynamic stability, a departure from the box-like form of satellites that operate in the complete vacuum of space.
It stays aloft thanks to an ion engine that began with a stock of 41 kilos (90.2 pounds) of fuel and is now down to about two kilos (4.4 pounds), Rune Floberghagen said from an ESA symposium in Edinburgh, Scotland.
- Did the spacecraft orbit so low that the engines had to run continuously to counteract drag, or were they just run intermittently? If intermittent, roughly what was the duty cycle.
- Roughly how much lower was GOCE's drag compared to a typical spacecraft, or to a sphere of the same mass. Did it have a drag coefficient as low as a real Ferrari?