Another Arctic milestone was reached this week when a cargo ship fortified against ice completed a solo trip through the hazardous Northwest Passage.

The MV Nunavik, owned by shipping firm Fednav and built in Japan, left Canada's Deception Bay on Sept. 19 and rounded Alaska's Point Barrow on Tuesday (Sept. 30). The Nunavik is the first cargo ship to sail through the Northwest Passage without an escort from icebreakers, Fednav said.

The polar route to the port of Bayuquan, China, is about 40 percent shorter than the route through the Panama Canal, according to Fednav. Through fuel savings, the company expects to reduce its greenhouse gas emissions during the voyage by about 1,300 metric tons (1,430 tons). [On Ice: See Stunning Images of the Canadian Arctic]

The ship is carrying 23,000 tons of nickel ore mined in Deception Bay in Canada's Nunavik province.

MV Nunavik is a polar class vessel that can break through ice nearly 5 feet (1.5 meters) thick at 3 knots (3.4 mph), the company said in a statement.

The melting of Arctic ice has opened up several new Arctic routes to commercial shipping. The shortcuts help companies save on fuel and are deeper than the Panama Canal, which means companies can increase the amount of cargo per trip.

The first cargo ship to sail through the Northwest Passage completed the route in September 2013, with an icebreaker escort from the Canadian Coast Guard. And in 2012, a Russian ship sailed from Norway eastward to Japan. Cruise ships and personal yachts have also successfully made the voyage, some unassisted.

Though ice is thicker this year around the passage's islands and inlets than in previous years, the Nunavik never encountered any thick ice or chokepoints that hindered the crossing, according to the ship's blog.

But Arctic navigation challenges remain. For example, ice often lingers in the Northwest Passage longer than in other regions of the Arctic. The icy islands also make for tricky navigation.

The first attempt to navigate the Northwest Passage, in 1845, ended in death for the crew of 129 when the ships became trapped in ice. Canadian scientists discovered one of the ill-fated ships, the HMS Erebus, earlier this month.