Seasat
Perhaps I should have pointed out the implications for MH370 more clearly in my previous reference to my involvement with Seasat in 1978.
If the military had that in 1978 (and it was built for civilian purposes), what satellite side scan synthetic aperture radar capability over the world's oceans must the big powers have by now?
The only possible reason I can see that military data hasn't put an end to this search long ago is that the area must be swarming with far too many equally likely targets.
Look how many the French satellite came up with through three well-space tiny holes through a cloud sheet.