The Lost Missile relies on stock footage (you see the same B-66 take off at least 3 times in the "maximum defense" montage) and EXTREMELY limited animationrotoscoping, but if you can get past that, the story is surprisingly good right up until the "this is the MacGuffin that will save us, so we'll ship it without a proper military escort" plot device near the end (the same stupidity as seen in the War of the Worlds).
Oddly, the science behind the story isn't all that flaky. By its nature, a starship is a de facto weapon of mass destruction. If it were knocked into an exceptionally low orbit (as happens in the first five minutes), whatever protects the ship from interstellar gas, dust, and radiation (assume it's a whopping STRONG magnetic field) would raise holy ned with the atmosphere as it plows through -' the killer heat from the missile isn't simply the heat of reentry, it's a byproduct of the stardrive. We learn very little about The Lost Missile (mostly just the incredible destruction its unplanned ball-of-twine orbit would do). Lee Gordon (Producer) didn't even pay for a model of the missile; instead, Lester Wm. Berke (Director) used and reused and re-reused (etc., etc.) the same pitifully few drawings of the interloper (in order of frequency: one shot from the side passing left-to-right, one shot 30° off face-on, one shot from above -' used in conjunction with the most destructive wake you will probably ever see done for $100 or less).
Some striking features: the LACK of a monster -' The Lost Missile is deadly beyond belief (unless it's stopped, it will kill everybody on Earth, but it wasn't intentional); the heavy-handed, but necessary actions of the Civil Defense wardens; the way the secretaries bypass military restrictions via the old girl's network; the relentless music that conveys the unstoppable nature of the threat; and the "happy" ending (SPOILER: we survive) that isn't happy -' it shows the cold equations of human sacrifice.
I would have LOVED to have seen Mystery Science Theater 3000's take on The Lost Missile.
Review by user_4574 from the Internet Movie Database.