[freepersup]

Good catch- thermal battery it is- the ole 9B17

The rechargeable grip stock explains the blue tube vs the OD green grip stock. Either the blue is inert (training) or NATO blue (or perhaps another Warsaw state). Perhaps the launcher was fired and now sports the replaced rechargeable grip stock. ? Would the grip stock contain the booster propellant ? Rechargeable... ?

sic-armament

[Cold Heat]

The booster would be in the missile. Similar to the U.S. LAW rocket. All the propellant burns before the thing leaves the tube. (no blast in the face, just don't stand behind it!)

Then the main motor lights up.

[Cold Heat]

I have no clue. I do know, that it takes power to launch the missile.

A thermal battery would be nice, so the shelf life would not depend on a battery holding a charge. It is likely, the warmth from your hand would be enough to create a voltage potential and fire the missile.