My wife and I were on the back deck at about 10:30 with two other friends when my wife said "what is that?!". I turned to look where she was pointing and saw 4 blue lights in a line that flashed quickly in sequence and then turned green and flashed, alternating between blue and green as it continued to flash, travelling from east to west in the northern sky at a fair rate of speed. It appeared to be about an inch long from "first light to last light". It disappeared behind the rooftop of our neighbour's garage so I ran out front and observed it travelling SW until it disappeared behind the roofs of the houses. Approximately 20-30 minutes later one of our friends and I were still on the deck (my wife and his girlfriend were in the kitchen at this time)and we saw it return on the same flight path but appeared to be closer this time. I could see the dark outline shaped like a "slightly flattened rugby ball". The lights were still rapidly flashing in succession and changing on each "flash cycle" from blue to green. My friend and I both saw it the second time, and he said "Do you see that?!" I said "Ya, I see that". He said "what is that?", I said "I have no idea". The object then appeared to hover slightly in the sky (I believe this is because it changed direction and pointed north, so the object appeared to "pause" in the sky as its trajectory changed) and a red light flashed quickly once, and very brightly from the same area the blue-to-green lights were flashing, then three red-orange squares in a line immediately lit up very bright (they did not "flare up", but were immediately very bright and very square) and we could see from the lights the illuminated (back?) of the craft. From the light of the red squares, you could see that they were aligned on a definite object of some kind, and the craft was textured in an apparent "mechanical" surface. The object then shot off at an incredible rate as the red squares went dark again. We watched the continuing blue to green lights that were flashing this entire time until it vanished in the distance. it took about 2 seconds for it to disappear (we watched it until it became so small we could no longer see it. We time planes that leave the airport (though the angle of the object's trajectory in the sky was a little different), and it took approx. 10 minutes for the planes to disappear from view, much, much slower than the object we witnessed.The first sighting lasted almost two seconds as it passed over, and another 3-4 seconds as I watched it from the front until it disappeared over the roofs. The second sighting lasted 8-10 seconds, and was noticeably closer than when we had seen it the first time. If you hold an outstretched arm and spread your thumb and index finger, it was about two inches from "thumb to finger" long (side to side), and about 3/4 of an inch wide (top to bottom) during the second sighting. I would estimate it to have been no more than a few kilometers away. It was very distinct and very visible. We did not have to "try" and see what it was, just to try and figure out what we were seeing.The first time the object was seen, there was the sound of a plane heard (we live in Coventry in Calgary and so are close to the airport and flight paths), but once the object had moved across the sky the first time, we then saw the plane in the east as it left from the airport. The object itself made no noise. We see planes leaving the airport and on landing approach all the time and are very familiar with the flight paths. The object did not follow any typical flight path at any time. The second sighting of the (assumed) same object there was no sound in the sky and no planes seen or heard. The object made no noise whatsoever. It was completely silent.