The race runs twice around the clock and is a marathon of endurance for both the drivers and the car. The 24-Hour is no doubt the toughest and best-known sports car race in the world and with 16 race wins, Porsche are the most successful manufacturer.
The German marque has been absent in the blue riband LMP1 class for 16 years and the team is looking to Hartley and co-drivers Mark Webber and Timo Bernhard to be there or thereabouts at race end, along with Neel Jani, Marc Lieb and Romain Dumas in the other car.
"This is the first official test day and everyone is obliged to go and drive," said Hartley. "We're going to try and put as many kilometres on the car as possible.
"It's the first time the cars will have been to Le Mans and it really is a specific and special kind of circuit. There are very, very high-speed straights where we will get up to 320km/h, combined with some really slow sections.
"I can't think of any other track like it in the world. The majority of it is public roads, which means there's a crown in the middle of the road and it's quite bumpy and there's not a lot of run off either.
"During the day we'll be doing set-up testing, tyre testing and also putting laps on the car. The cars have been designed to be fast at Le Mans and this will be the first time we'll be able to see how they all go."
In the opening two rounds of the world endurance championships, Hartley's car has shown good pace and the team are confident of doing well at Le Mans.
The drive train package on the car is sophisticated, incorporating the hybrid technology and works well, especially on the drive out of the corners.
One of the factors that probably helped Hartley get his fulltime gig with Porsche is that he's been to the race twice before and done pretty well.
"Since it is such a specialised track and race, having raced there before would have helped me get the drive. The style of racing, the 24 hours of racing, and everything else makes it very unique and I love racing here.
"On paper, the track doesn't look that exciting, but when you drive at full race speed with all the track about you at night -- the straights are so long you can't see the next corner -- trying to pick your braking mark with much reference makes you concentrate very hard.
"Combine the speed of the straights, and the technical corners, will really put our cars to the test. It's an incredible track to drive."
Hartley's previous stints on the Circuit de la Sarthe will stand him in good stead, and although he is the youngest bloke in the squad, he's been doing this for a fair few years now and is keen to impress.
