That depends on what you mean by "preserve" and that depends on exactly how information is stored in the brain, the answer to which no one really is quite sure. Is it stored chemically? Is it rather to do with which neurons a given neuron is connected to through its axons? Is it something else entirely? Even the experts don't really know. If the answer is chemical then the information defining your personal identity would be extremely sensitive to the abuse it's going to receive in even the earliest stages of death. But if it has only to do with the connectivity (which actually, oddly enough, is an entirely digital code, if you think about it. Is neuron 4623429 directly connected to neuron 900521? Yes or no? 0 or 1?), and possibly only the shortest term memories are held chemically, if that was to be the case, then your personal identity may even survive your brain being freeze-dried and stored in vacuum. (What, you thought I was going to suggest then storing that digital code in a super-duper hard drive? Some would be satisfied with that. But then, it would just be a computer with an emulation of the real thing. Would they also be satisfied to die and have an exact replica of them with their memories live on? Even if that replica was started up BEFORE they actually died? And what difference would it make whether it was a little before or a little after or at the same time?) If that was the case (the freeze-drying part, not the part in parentheses), then that would be your best answer. Of course, restoring it to function would really be quite something, wouldn't it? But you know, that which we call "room temperature" is actually quite hot as far as most of the universe is concerned. It wouldn't require any equipment at all to keep your body QUITE cold, so long as it was left drifting in space a little farther from the sun than the planet Earth's orbit. Of course, you'd also want to protect it from cosmic radiation, so possibly the answer is to have your body left in the heart of an asteroid. Then again, that would be very inconspicuous. Some alien race far in the future wouldn't see that asteroid as anything unusual and worth investigating. Perhaps then something should be attention getting about that asteroid. Maybe construct a structure that is obviously artificially made, like a big cube of solid iron, and let your body sit there in its core for eons to pass. But you know, why would your life with these aliens be any better than it is now? You might as well end it all for good and forever with a bullet right now. Whether it's destroyed by quantum fluctuations over the next 10 to the 40th power years (some people say that quantum tunneling will cause everything to decay into iron-56 after such time, and according to the standard model, protons decay into 2 positrons, an electron, a neutrino and some gamma rays and of course one of the positrons is likely to annihilate with the electron, and if it was in an electrically neutral atom, so will the other positron) or eaten by insects in the next week, it'll be destroyed eventually, and then it might as well never have existed in the first place. It's just your survival instinct that keeps you from offing yourself this minute, there isn't any logic or reason behind it. So why fight so hard to prolong it with such schemes? Granted with them available, being a slave to that instinct, you won't be able to resist it, but is it really that great a prospect being a slave to a basic instinct for an eternity? Live for a while, and then when you're tired of it, die. That's the best way, given that living forever is not an option. Believe me. It will become unbearable after a long enough time passes. It won't even be that long. A blip as far as the universe is concerned.