Here’s the bad: The ship, Kapitan Dranitsyn, burned so much fuel that now it, too, has to be resupplied. Another icebreaker is on its way to bring it more fuel.

Such are the logistical complexities of the expedition, known as Mosaic, in which a German research ship, Polarstern, has been drifting with the sea ice in the Arctic Ocean since October with a revolving complement of scientists. The ship is expected to come out of the ice east of Greenland in September after gathering a year’s worth of data on conditions in the remote Central Arctic.

The Kapitan Dranitsyn left Tromso, Norway, on Jan. 29 with 43 tons of food, fuel and other supplies for the Polarstern, as well as a replacement team of researchers and technicians for what is the third two-month leg of the expedition. The resupply trip was expected to take about two weeks, but the icebreaker ran into trouble from the start, when a storm in the Barents Sea forced it to anchor off Tromso for the better part of a week.

Once underway, the ship encountered sea ice that had gotten much thicker as the winter progressed — doubling to more than 5 feet, or 1.5 meters, in places. The Kapitan Dranitsyn finally arrived at the Polarstern on Feb. 28.

After several days unloading the supplies and transferring personnel across about a half-mile of ice in dangerous conditions (a wind chill of minus 72 degrees Fahrenheit, or about minus 58 Celsius), the Kapitan Dranitsyn left for the return trip to Tromso. But calculations showed that it would not have enough diesel fuel for the journey.

So on March 3, another icebreaker, the Admiral Makarov, left Murmansk, Russia, with a load of extra fuel to intercept the Kapitan Dranitsyn on its way. Early this week, the two ships were about 350 miles, or roughly 560 kilometers, apart.

Markus Rex, an atmospheric scientist who is Mosaic’s leader, wrote in a blog post that the delay in resupplying the Polarstern was “absolutely in keeping with what had to be expected” given the ice conditions.