Skarv says the ship will be optimized for lower speeds, so don't expect ammonia-powered ships to cross oceans just yet.

Add Yahoo as a preferred source to see more of our stories on Google. Northrop Grumman's Cygnus XL cargo ship, carrying more than 11,000 pounds of equipment and supplies for the International Space ...

When people think of big engines, they usually think of regular gas engines, like Koenigsegg's 2,300-horsepower monster. However, if you think about it, there are many much bigger vehicles out there, ...

Northrop Grumman's Cygnus XL cargo ship, carrying more than 11,000 pounds of equipment and supplies for the International Space Station, is scheduled to rendezvous with the space station Thursday ...