Did I read that right, they launched it from a platform IN the ocean? Why would they do that?
Low earth orbit is about 8 Km/sec. If you launch from latitude 45 degrees, your initial orbit has an inclination of 45 degrees. When your rocket crosses the equator you need to have a burn to change your inclination to 0 degrees. From 45 to 0 degrees takes 6 Km/sec of delta V. So from the equator it takes 8 Km/sec, and from 45 degrees it takes 14 Km/sec. That is 75% more energy to lift the same amount of stuff...
Because it's obviously much more stable than launching from the ground! And it has the added benefit of making it much harder for others to keep an eye on what you're doing out there ;-)
The Earth spins at its fastest rate at the equator, about 1000 mph.
If you launch to the east, your satellite gets a gravity assist in reaching orbital speed of about 17,000 mph.
This means you can launch more weight with less rocket fuel or a less powerful rocket.
Unfortunately, launching a rocket from the ocean, many miles from shore, is a daunting logistical and engineering challenge all by itself.