Greetings,<br /><br />I'm a new member to the forum, though I've been browsing space.com for a while. Skipping the formalities, I'm writing a paper on interstellar space travel, and I've got a few questions.<br /><br />I read in another thread on the forums (Unfortunately, once I got my account activated, I could not find the thread) that if you accelerate fast enough the cosmic microwave background radiation will become blueshifted and essentially fry you and your ship. Is this true? If so, what speed would this occur at?<br /><br />My second question is: Would it be possible to use a solar sail-like device to slow down upon reaching another solar system? In the paper, I'm trying to outline a rough plan for an interstellar probe, and I was wondering if such a device would work for breaking at least somewhat, and at what speed a probe would need to be traveling for it to be a viable method of breaking if it is indeed possible.<br /><br />Last question: Would using Proxima Centauri as a gravity-assist point work for a mission toward Alpha Centauri A and B? I'm a bit of an amateur at the physics of space travel, so I apologize in advance.<br /><br />I hope someone can help, and thanks in advance.