Additionally, don't confuse "encoded" with "encrypted". Unless you're into signals and computer science, you may think they're the same thing, but they're not. Everything sent digitally is encoded. Encoding is the process of turning the information into a series of 1s and 0s which can be transmitted to a receiver, where they can then be decoded into something useful. For a very simple example, this post, written in English, will be encoded using a code called ASCII, a standard for representing characters (letters and digits) as numbers, which can then be represented in binary, which in turn can be transmitted across the Internet. When it gets to your PC, your computer takes those 1s and 0s, decodes them into characters, and then draws those characters onto your monitor. The letter "A" is never sent across the Internet -- instead, the number 65 is sent, which in binary is 1000001. So when the computer wants to encode the letter A, that's what it sends.<br /><br />That's a very simple example of encoding, and a well-known, standardized one. A spacecraft such as MRO may not use standard encoding methods; because its mission is very specific and its bandwidth is so intensely valuable because of the rarity of its data, engineers may have devised an entirely unique system of encoding the data which optimizes the bandwidth useage. Odds are, though, they've used a preexisting system, so if you can get a hold of the equipment, it should be at least theoretically possible to pull data out of the stream. I suspect you would not have enough signal strength to do it, though; the dishes normally used to communicate with these probes are very large, much larger than a hobbyist could afford.<br /><br />Encrypting, on the other hand, is the process of garbling the data in a very specific way so that it is useless to a third party intercepting the signal. A key of some sort is provided so that the recipient can then decrypt the signal and make use of it. Encryption can be use <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>