I know what you mean...
i think that the governing body has a rough guide of classing satellites smaller that a few miles big as planetesimal's or rocks..
Like its sister moon Phobos ( Greek for "Fear") is non-spherical in shape. Probably , and it is also a captured asteroid.
i hope that nasa manages to catch a similar transit with the larger and closer orbiting `Phobos`, which could blot out half the sun for 40-30 seconds or more.
Somewhere on a planet far, far away, near the martian equator, Phobos eclipses the sun nearly every day.