So I have already done... a lot of reading on this subject lately. A lot. You wouldn't believe. My maths is... functional, probably far above 'average', but when it gets into the realms of the 'rocket equation' and relativistic effects I pretty much have to take what I'm reading for granted. Problems arise when I read two different essays that each end up contradicting each other.
For example, I read in one place that the maximum possible velocity for a chemical rocket is 5km/s. But I'm fairly sure that's not the case, except perhaps that's the maximum velocity of rockets currently in production, due to fuel-tank sizes?
But anyway, to cut things a little short (too late I know) - I have found and read the 'relativistic rocket' text, which seems to be sent around a fair bit on here as a good source of information, as well as a couple other similar pages and essays. However these all only give data for either hypthetical "100% efficient engines", or for antimatter engines, or in some cases a 100% efficient antimatter engines. None of which is helpful, as they don't actually exist.
What I am looking for is essentially the same information, but for either the best Ion drive engine we currently have (known prototypes are allowed), and/or the best chemical or more traditional 'rocket' type engines we have.
What I am looking for is - (for both the ion and rocket)
- Amount of fuel/propellant needed to get the ship up to 0.05C (and then back down to stationary) for a 4.7ly trip.
- Same question, but for 0.2C.
- What the maximum acceleration would be (mostly for ion)
- With a maximum acceleration of 9.8m/s, how long would the ship need to be accelerating for.
I know the relativistic rocket page has this information, but only for 'fake' engines. 10kg per 1kg of payload was a major answer I was looking for... but I need it for non-100% efficient engines. And I can't seem to convert it myself, as nowhere actually seems to list the efficiency of our current generation of engines! (They often list it as 100% efficient at certain points, but I assume thats relative to its own profile).
Hopefully this made vague sense... Pointing me in the direction of figuring out the answers would be great too!
Edit: Realised I didn't specify a vehicle mass. Reasoning for this is that I wanted a similar result as the Relativistic Rocket page, that gives it in KG of fuel per 1kg of payload. I assume in their calculations they take into account the fuel's own mass needing to be accelerated on top of the payload.