Here's what he'll face on the record-breaking trip.

scott sears south pole
Credit: Getty Images/Max Mumby

Tennis great Andy Murray isn't the only one in the family who is cool under pressure.

Murray's brother-in-law Scott Sears, 27, will brave temperatures as low as 58 degrees below zero in an attempt to become the youngest person ever to reach the South Pole, unsupported, on a solo expedition.

Sears, a British Royal Army lieutenant, set off Friday on the journey that will take him 685 miles from the edge of Antarctica to the South Pole.

In addition to deadly cold, he’ll face challenges that include avoiding deep cracks that can be hidden under thin layers of ice and winds that can reach 150 miles per hour.

Sears' plan is to ski 10 hours a day in blocks of two hours at a time. If weather conditions permit, he hopes to travel 25 miles a day.

He’ll be wearing a compass on his chest as the high winds and low temperatures in Antarctica can lead to white outs, making it tough to know which direction to head in.

Sears will also have nearly 200 pounds of supplies with him, including one sled and two skis, which he will carry throughout his journey. He expects to burn anywhere from 7,000 to 9,000 calories a day.

Lewis Clarke, from the U.K., holds the Guinness World Record as the youngest person to trek to the South Pole for his journey in November 1997 at age 16.

Last year, Luke Robertson, 30, became the youngest person from the U.K. to complete a solo, unassisted, and unsupported trek to the South Pole, according to BBC. Categories for South Pole trek records can vary greatly depending on whether explorers are getting wind assistance and whether they're walking, skiing or using another mode of transportation.

Shears is attempting the record-breaking trip to raise £25,000 ($33,047) for the Gurkha Welfare Trust, a charity that supports veterans of his army unit. He will be regularly providing updates on his journey on his blog.

In November of 2013, Prince Harry, who was a Royal Army captain, and "True Blood” star Alexander Skarsgard joined 12 wounded soldiers on a 208-mile ski trip to the South Pole, teaming up with the Walking With the Wounded South Pole Allied Challenge for the trip.