Reentry from the Moon is far harsher than from Earth orbit, and that one difference shaped two completely different spacecraft designs. Orion spacecraft returns at about 25,000 mph, facing temperatures near 5,000°F, which was demonstrated during Artemis II when she brought her crew back on April 10, 2026. The Space Shuttle, by comparison, reentered from low Earth orbit at around 17,300 to 17,500 mph, with heating closer to 3,000°F. That extra speed from lunar return means Orion carries far more energy into the atmosphere, making her descent much more intense than anything the Shuttle experienced.
That energy difference explains why their heat protection systems are completely different. Orion uses a thick ablative heat shield that slowly burns away, carrying heat off the capsule during descent, which is ideal for one time, high energy reentry followed by parachute splashdown. The Shuttle instead relied on reusable silica tiles and reinforced carbon carbon on critical areas, designed to survive repeated flights and allow a runway landing like an aircraft. In simple terms, Orion is built to survive a single, extreme deep space return, while the Shuttle was designed for reuse after lower energy missions in Earth orbit.