On Thursday, NASA showed off a new look for its Orion crew capsule — the spacecraft that could eventually take humans into deep space and on to Mars someday. Future versions of Orion will now sport a shiny, metallic coating that will cover a large portion of the vehicle's outer surface. The coating is part of Orion's newly updated thermal protection system, which protects the spacecraft from the extreme hot and cold temperatures it experiences during space missions.
Currently, one of the main components of Orion's thermal protection system is its heat shield, which covers the "belly" of the teardrop-shaped spacecraft. When Orion returns to Earth from space, the shield faces into the atmosphere during reentry, helping to slow the vehicle down and protect it from the intense heat generated during the fall. A grid of specialized thermal tiles cover the rest of the spacecraft — known as the back shell — also limiting the intense heat felt inside the capsule.
However, Orion needs to be able to keep heat in just as much as it needs to keep heat out. When the capsule is in deep space, it will experience extremely cold temperatures, and it's going to need a way to limit heat loss. That's where this new metallic coating comes in. The silvery material, which is similar to what's used in the main heat shield, will be bonded to the back shell tiles. The coating will help keep the back shell's temperature somewhere between -150 to 550 degrees Fahrenheit when in space.
"You’re trying to hit this sweet spot because when you’re looking at the sun, you don’t want to get too hot, and then when you’re not looking at the sun and instead in darkness, you don’t want to lose all the heat that the spacecraft generates," said John Kowal, who's in charge of the thermal protection for Orion.
NASA engineers are making these system enhancements in preparation for the next big test of Orion, called Exploration Mission-1 (EM-1). Scheduled for no later than November, 2018, it will be the second uncrewed test flight of the capsule, taking Orion into distant orbit around the Moon. The vehicle will be in space for more than three weeks for the mission and then return to Earth at speeds of 36,000 feet per second. Temperatures during reentry are expected to exceed 4,000 degrees Fahrenheit.
Orion's test flights have experienced delays, though. EM-1 was originally supposed to be in 2017 but then slipped to 2018. And Exploration Mission-2, the first crewed flight of Orion, was also recently rescheduled. The mission will happen no later than 2023, when it was originally scheduled for no later than 2021.