How Small Is Big Enough?

chemical handwarmers. If there are indeed volatiles in the NEA subsurface
then the heater should cause a cloud to form which can be observed from
earth and studied spectroscopically.

I am a bit confused. Is the probe supposed to survive the impact ? That would require a large propulsion capability to match veolocities with the NEA. At orbital velocity the probe would be vaporized by the impact.
The energy of the impact itself would release quite a lot of heat, so maybe there is no need for the heater.
The other variant involves hitting a nickel-iron NEA with an impactor
that releases CO, forming carbonyls which can again be studied Where does the CO come from ? Does the probe carry it along ? What causes the release ?
Cheers,
Charles R.