As part of an all weekend event at the Old Akihabara Radio Building for Steins;Gate, which includes a tie-in with the Radio Building, the exterior of the building has been transformed into the "crashed satellite" scene from the prologue of the game and episode 1 of the anime. Here is a photo tour via the internet of the the set-up and final result:
Starting with the final result, taken by Akiba-PC Hotline!:
Here is how it looks in the game for comparison:
A picture from a short distance away:
(Photo via http://twitpic.com/76ow1z)
Close-up of the "man-made satellite":
(Photo via http://twitpic.com/76nzmu)
So, how did they do it? Here's the secret:
The "damage" is in the artwork on the exterior of the building.
For those who are curious, here is the how the building normally looks via Google Maps.
And here is your literally "man-made satellite":
And from the side:
Additional photos can be found at the sites below. Akiba-PC Hotline! also has a step-by-step photo summary of the fitting of the satellite onto the building below the main article and pictures.
All photos copyright original creators.
Steins Gate ©5pb/Nitroplus
Update: Added huke's edit.