A "light emitter visible to a space-based telescope" is a means of communication. And what is a "control module"? Without a control system of some sort, how's it supposed to take and transmit pictures? And why do you think something makes such a probe impossible?

@ChristopherJamesHuff - I wish it would be possible. But I did not see a discussion in this regard, so there could be some technical limitations. Electronics that can withstand gun barrel g-forces would be very basic. Small camera and timer to trigger image transmission.

@OrganicMarble - small battery.

Credit card sized spacecraft have been flown, so bullet-size isn't impossible. There's power density limitations but I don't think there's anything truly impossible, especially if you're generous with what the size of a bullet is.

You said bullet-sized, your question said nothing about actually being launched as a bullet from a gun. And if that's what you have in mind, a bigger problem is the limited muzzle velocity achievable.

FYI, mentioning the asteroid belt doesn't make the question about the asteroid belt, so the "asteroid-belt" tag is inappropriate. You should also mention where you got that picture from and add an image description.

@ChristopherJamesHuff - 500 m/s (magnum bullet velocity) would not be sufficient delta-v for the Asteroid Belt?

500 m/s is not even close to tye speed needed to get to tye asteroid belt. For example, it took about 4500 m/s to get to Ceres. The fastest bullet in the world is the .220 Swift, which has a speed of 1,422 m/s. In addition your bullet needs a transmitter and antenna, and a camera with a decently large lens. Not going to happen.

What's it going to take pictures of? If, for instance, you intend to get good close-up pictures of an asteroid, you need sensors to find it and guidance to get close to it. Just blindly taking pictures of whatever patch of space you get shot towards is probably not a good use of resources.

@Cadence - In my understanding, a vacuum of space allows for unlimited precision. You can shoot a bullet precisely at the asteroid of your interest and have a timer to trigger the camera right before the approach. All necessary parameters will be preprogrammed before the bullet leaves the barrel.

...no. It just means there's no aerodynamic effects on the trajectory. Guns do not have "unlimited precision", either in direction or muzzle velocity. Launch rockets can correct their trajectory until they run out of propellant, and their payloads still typically require additional corrections that only become apparent with continued monitoring of their trajectory.

@TheMatrixEquation-balance boring chemistry stuff means you will not get quite identical burn rates out of out of a classical chemical gun, less than a meter per second for good batch control but even 1cm per second wrong on a 9 month journey is quite a miss (less than the 232km 9*30*24*60*60 gets you but right magnitude). You'd need some sort of fine tuning system in the projectile unless you genuinely go shotgun style and fire a pattern.

@GremlinWranger - "unless you genuinely go shotgun style" - this is a good idea. Speculating about $20,000 per shot, it would be affordable to shoot 5-10 projectiles per target.

Agree - you need to clarify the question. Are you just asking about whether we can use small probes, whether ballistic deployment is possible, or what?

You might also FOCUS the question on a few things. Such as: if we had a probe of x dimensions, what is the best performance we could expect from a [visible light sensor] [some other useful sensor] [laser communications thing] and what are the engineering challenges that would need to be overcome to obtain useful data?

@SpaceLawyer - I agree, it was a wide net question. But it generated very interesting answers and ideas. When someone is talking about technologies that are not on a drawing board yet, it is hard to be specific.

What I don't understand, is why no one can support this question. I have already been suspended for 7 days for a downvoted question.