I need a portable storage device for satellite imagery.
I have seen this device My Book Studio Edition II, could you please advice me on other possible devices.
You could look into getting an external enclosure with 2 bays for 2x 2TB drives.
Something like the Vantec Nexstar3-mx perhaps. They have one which has USB and another which offers eSATA.
A 2x2TB unit with the Vantec Nexstar3-mx USB will set you back R4900 or so. This is with just 5,900RPM Seagate drives.
Unfortunately I don't see any portable quad dock units. If there were they make it a whole lot cheaper by using 1TB drives, but then I wouldn't call it "portable".