How Far Can My Model Rocket Reach in Space?

[malfdawg]

I've built a model rocket with the longest burning engine I could find, a light sensor in the nose cone, accelerometers on the forward fins all connected to an Arduino pro mini microcontroller programmed to keep it pointed at the brightest source of light. If I attach this rocket to a balloon and set it so that the microcontroller fires the engine when the balloon dramatically loses pressure (it pops), and assuming everything goes right - the rocket expends most of its fuel while pointing at the sun/moon when they are at the highest point in the sky... How far could my rocket get? Can it survive the conditions of space?

Yes I know building a guided rocket that chases the brightest light it sees is probably frowned upon in some places, I doubt it'll be a problem where I live.

 

[russ_watters]

Welcome to PF. Based on the tone of the question, I'd say you'll get a few thousand feet above the balloon. Your biggest problem will be that your control system won't work at high altitude - there isn't enough air for the fins to grab.

Getting into space is not as easy as you think.

 

[harralk]

I'm no expert on space but I would think that controlling the rocket's direction through vectored thrust rather than movable fins would result in better control in a low pressure atmosphere.

But perhaps you should clarify what you mean by "space". The Earth's atmosphere has several regions and actual "space" doesn't begin for several hundred miles.

My opinion is that if you should manage to make it to the outer edge of the atmosphere the extreme cold will freeze the electronics (causing them to malfunction or stop altogether) and some important stuctural components. Certain materials such as some plastics and even certain grades of common metals become very brittle at extreme low temperatures and the vibration from the engine could shatter the rocket.