JWST’s eagle-eyed astronomical acumen stems from its gigantic 6.5-meter primary mirror. Composed of 18 gold-coated hexagons forged from featherweight beryllium, the mirror is taller than a four-story building, and once launched will be the largest ever flown in space. Carrying science instruments to detect very faint infrared sources, the observatory must operate at ultra-cold temperatures requiring a multi-layered tennis-court-sized “sunshield” to insulate it from the Sun’s heat.

Now toss in for good measure where in space JWST will reside. After launching on Europe’s Ariane 5 rocket from French Guiana and following roughly 100 days of space travel, the observatory will be parked one million miles away from Earth, far beyond the orbit of the moon. It will reside within the Earth-Sun Lagrange point, or L2, a locale where the collective gravitational tugs of the Earth, Sun and moon allow the telescope to stay aligned with our planet as it moves around our star. Out there—way, way out there—JWST’s operators will remotely test and tweak the observatory with commands beamed from Earth, bringing it fully online and ready for science within six months of its launch.