Orion CPAS
When NASA’s Orion spacecraft comes screaming back from the Moon, something has to slow it from a fiery plunge to a gentle landing on the water. That job belongs to Orion CPAS, the parachute system that carries the crew home.
Quick facts
- Full name: Capsule Parachute Assembly System (CPAS).
- What it does: slows Orion’s Crew Module (the cone-shaped capsule that holds the astronauts) after reentry for a safe ocean splashdown.
- Total parachutes: 11, in four types: 3 Forward Bay Cover parachutes, 2 drogues, 3 pilots, and 3 mains.
- Drogues: 2 parachutes, each about 23 feet (7 meters) across.
- Mains: 3 parachutes, each about 116 feet (35 meters) across, weighing roughly 300 pounds, with about 10,000 square feet of fabric apiece. Open together, they cover nearly an entire American football field.
- Capsule mass at descent: roughly 21,000+ pounds.
- Maker: Airborne Systems, with development and testing managed by NASA’s Johnson Space Center and Jacobs.
What it is
CPAS is not a rocket engine. It is a deceleration and landing system, meaning its only job is to slow the capsule down. It is the final stage of Orion’s descent, taking over after the spacecraft has plunged through the atmosphere. The design traces back to the Apollo program’s Earth Landing System, scaled up for the heavier Orion capsule. Because the parachutes are used once and then released, CPAS is an expendable, single-use safety system.
How it works
CPAS opens in a precisely timed sequence during the last few minutes of the fall. Most chutes are fired out by mortars, small explosive launchers that punch the parachutes clear of the air the capsule churns up behind it (its turbulent wake), so they open at the right moment without snagging.
First, three Forward Bay Cover parachutes pull away the protective lid covering the parachute compartment, around 25,000 feet. Next, two drogue parachutes deploy near 22,000 feet to slow the capsule and hold it steady and pointed the right way. Then three small pilot parachutes fire; each one acts as an extraction chute, yanking one large main parachute out of its pack near 6,000 feet.
The mains and drogues use a technique called reefing, where lines hold each canopy partly closed at first, then release in stages. Each chute opens to about 3.5 percent of its full area, then about 11 percent, then 100 percent. Reefing-line cutters fire on a timer so the canopies inflate gradually rather than all at once. Think of easing a car to a stop instead of slamming the brakes; this keeps the opening shock gentle enough for the crew and the structure. Fully open, the three mains bring Orion down to a soft splashdown.
Why it matters
CPAS is the system that brings the crew home alive. It is the only thing standing between a capsule reentering at up to about 25,000 miles per hour and a survivable landing, which makes it human-rating-critical, the highest reliability standard NASA applies to spaceflight hardware. It is used on every Orion return, putting it at the heart of the Artemis program, NASA’s effort to send astronauts back to the Moon. Its fault-tolerant design can land safely even if one drogue or one main parachute fails, a margin earned through one of the most extensive parachute test campaigns ever run.
Notable examples
- Exploration Flight Test-1 (December 5, 2014): Orion’s first orbital flight test. CPAS deployed after a roughly 20,000 mph reentry and landed the capsule safely in the Pacific.
- Artemis I (launched November 16, 2022; splashdown December 11, 2022): an uncrewed flight around the Moon. After a roughly 1.4-million-mile journey, CPAS deployed flawlessly for a Pacific splashdown.
- Artemis II (splashdown April 2026): the first crewed Artemis mission. CPAS safely returned the astronaut crew to a Pacific splashdown off the California coast, with deployment beginning at altitude.
- Yuma Proving Ground tests: the U.S. Army site in Arizona where CPAS was qualified through airdrops, including deliberate failure cases. Testing there led engineers to switch the cords from steel to lighter, strong Kevlar.
One detail captures the challenge: the main parachutes are packed to the density of oak wood to squeeze into the cramped top of the capsule. And unlike capsules such as Russia’s Soyuz, which land on solid ground using retro-rockets, Orion comes down on water.
