What aircraft has this pattern of white strobe lights?
Twenty cycles per minute means it wasn't an FAA-approved aircraft, so it probably wasn't manned, or even a weather balloon.

Satellites need no anticollision lights.

The bright strobe combined with the longer fading lights suggests something homebuilt.  The light may have been adapted from consumer bicycle lights, which have quite a variety of patterns.  Professional lights such as Whelen's models prefer flickering to fading, for both efficiency and visibility.