Bringing Orion Home: How the U.S. Navy will pluck our future astronauts from the sea
Posted by Jason Davis
2014/02/14 12:16 CST
One day in the not-so-distant future, a spacecraft called Orion will splash gently into the Pacific Ocean under three striped orange and white parachutes. There will be astronauts inside returning from an expedition to a near-Earth asteroid or Mars. They will have been deeper into space than any previous human beings, but out of the millions of miles they have travelled, the last five will suddenly become the most important.
Somewhere nearby, Mike Generale, NASA, and the U.S. Navy will be heading directly for the Orion capsule as it bobs helplessly in the waves. Generale is the Orion Recovery Operations Manager and Recovery Test Director at Kennedy Space Center. His team will be aboard one of the Navy’s Landing Platform/Dock (LPD) class ships, which come equipped with a floodable hangar used to launch and retrieve other watercraft.
Orion won’t carry astronauts until at least 2021, when it is scheduled to take humans to a captured near-Earth asteroid. Prior to that, it will make two uncrewed test flights—the first of which is scheduled for September of this year. But before Orion departs on its maiden voyage, NASA and the Navy have some practicing to do. They must make sure they can quickly and safely pluck the capsule out of the Pacific Ocean when it returns home. And to do that, they’ll have to revive some techniques that haven’t been used since 1975, when America’s last Apollo capsule returned from space.
Crawl, Walk, Run
The training for Orion’s recovery began last August at Naval Station Norfolk, when NASA and the U.S. Navy practiced hauling the capsule into the well deck of the U.S.S. Arlington. The Arlington is a sister ship of the New York and Somerset. All three were named after Sept. 11 attack locations, and the New York and Somerset used steel from their respective wreckage sites in the boat’s construction.
“I always tell people that this class of ship is like a cross between an aircraft carrier and a submarine,” Generale said. LPD-class ships have cavernous 50 by 200 feet openings called well decks at their sterns. The well deck sits at sea level and can be flooded with 8 to 10 feet of water, allowing for the transport of ships like hovercraft carrying tanks and trucks to shore.
How does one flood and then dry a well deck?
“They have ballast tanks on board the ship,” Generale said. “It’s kind of like in a submarine—they fill those tanks with water and the ship will lower itself down into the sea.” To get the deck dry again, air is forced back into the ballast tanks. As the ship rises from the sea, the water is drained out of the well deck.
For the Norfolk tests, the Arlington was moored to its pier within the calm waters of Hampton Roads, at the mouth of the James River. “We wanted a very controlled environment,” Generale said. “We had very benign conditions.” The tests were part of an approach he calls “crawl, walk, run.” Norfolk was a crawl. For the walk and run, NASA and the Navy will replicate their efforts out on the choppy waters of the Pacific Ocean.
The Orion capsule used in the recovery tests is called the Boilerplate Test Article. It’s the same capsule NASA has been test-dunking in a large pool called the Hydro Impact Basin at NASA’s Langley facility. Following the Norfolk retrieval tests, NASA shipped the test capsule to Naval Base San Diego. It spent a couple weeks on the road, making stops on a social media tour.
At the end of February, Generale’s team and the Navy will head out into the Pacific for open water recovery training. The tests are currently scheduled to take place aboard the U.S.S. San Diego, but ultimately, any available LPD-class ship can be used. The Navy will spend four days setting Orion adrift and recovering it in progressively choppier waters. Generale hopes to wrap up testing by practicing a recovery in the maximum allowable conditions. “We hope to be able to recover in up to six foot seas,” he said. Because practicing Orion recoveries offers valuable training that can be applied to other situations, the Navy and NASA have an agreement that makes it very affordable to NASA, according to Generale.
How to recover a bobbing Orion capsule
Navy divers will initially approach Orion using Zodiac boats and rigid-hulled inflatable boats. It’s a dangerous job. Hazards include being pinned between a boat and the capsule, or falling in the water and getting trapped underneath.
“The capsule is essentially a big buoy out there bobbing in the water,” Generale said. “It doesn’t have a keel; it doesn’t have any rudders. You have this 16-foot diameter, 20,000-pound bobber bouncing around in the water.”
The LPD ship will release between 600 to 700 feet of a 1000 foot winch line—standard boating fare that you can purchase at your local marine store. “We use off-the-shelf hardware as much as we can to keep expenses down,” Generale said. Divers will secure the line to Orion using a handy built-in attach point. Tending lines will be connected to two additional attach points, and the LPD will slowly pull Orion forward to stabilize the capsule. The winch will then reel Orion into the ship’s flooded well deck.
“The recovery of the capsule is very similar to the recovery of an incapacitated hovercraft or landing craft,” Generale said. “It’s just a different vehicle and we have to get the Navy used to the nuances of our capsule as opposed to what they normally do.”
Inside the well deck is a recovery cradle with two rubber bumpers. Orion will be snugged gently up against the bumpers as line tenders on platforms inside the well deck help secure the capsule. As water drains from the well deck, Orion will be berthed onto its recovery cradle. “It’s really quite similar to recovering a boat on a trailer,” Generale said. “It’s what we modeled it after.”
Although there will be no crew in the capsule for the recovery tests, there will be eventually, and they’ll be eager for some fresh air. “One of the requirements for us is to get the crew out of the capsule within two hours of landing,” Generale said. While the Navy can’t control how far Orion lands from the recovery ship, they hope to have the hatch open in just over an hour.
“We don’t want to leave the crew inside the vehicle any longer than necessary,” he said. “If you’ve ever been bobbing around in a small boat—especially if you’re trying to get used to Earth’s gravity again—it can be quite a harrowing experience.” The crew will rely on two hours of battery power to recirculate cabin air and keep the capsule’s cooling system functioning. Once Orion is secure on the recovery cradle, an access stand will be installed next to the capsules’ side hatch and a flight crew will help the crew egress.
If necessary, a snorkel fan can be used to get the crew fresh air. It won’t be used unless needed to cut down on the risk of leaky thrusters seeping toxic gas into the capsule. As a matter of fact, something similar happened during NASA’s last splashdown in 1975. As the Apollo-Soyuz crew hurtled back to Earth, a pressure valve allowed fumes from the Apollo capsule’s reaction control system to enter the cabin. The crew was nearly knocked unconscious and spent two weeks recovering in the hospital.
A thruster leak could also spell trouble for the Navy divers approaching the capsule, so divers will have equipment on hand to check for leaks. They will also make sure Orion’s S-band communications antenna, which is used to communicate with the Tracking and Data Relay Satellite system, has been turned off.
“There are some antennas near attach points and we don’t want to irradiate the recovery crew,” Generale said, adding that divers would need to be relatively close—within a foot—to suffer harmful effects. Nevertheless, “people in small boats, bobbing around—you can’t always control precisely where you want to be.” The Orion crew will still be able to use other radio transmitters to communicate with the recovery ship.
Exploration Flight Test 1
Orion will conduct its first shakedown cruise in September on a four-and-a-half-hour mission called Exploration Flight Test 1. The short flight means bad weather at the splashdown site could delay the launch. The mission begins with a Delta IV Heavy launching Orion from Cape Canaveral Air Force Station. Orion will remain attached to the Delta’s upper stage for lap around the Earth. Then, the upper stage will reignite, sending the capsule to an altitude of 3,600 miles. It will be the highest a human-rated spacecraft has been since Apollo 17. The trajectory will give Orion 85% of the energy that it would have if it were coming home from the moon. As Orion comes back around the Earth on its second orbit, it will separate from the upper stage, which will perform a disposal burn to send it safely away from Orion and any shipping traffic.
Generale said Orion’s flight corridor is 25 miles wide. The capsule’s reaction control system gives it a slight amount of control as it falls back to Earth. Additionally, the capsule has an offset center of gravity, which causes it to spin slightly as it reenters the Earth’s atmosphere. This gives Orion some additional control over its ride. “We can steer a little bit left and right,” Generale said. “That’s something we’ve demonstrated on Gemini through Apollo.”
Eight minutes until splashdown, at just 10,000 feet, Orion’s forward bay cover pops off, revealing the “flowerpot,” the central connection point for the spacecraft’s parachutes. Two drogue chutes are deployed first, which stabilize the capsule’s descent. Pilot chutes are released next, which pull out three main parachutes. The capsule can safely splash down with just two parachutes inflated—something that NASA recently demonstrated during drop tests at the U.S. Army’s Yuma Proving Grounds.
As Orion descends, Generale and the Navy will receive updates on its position from Mission Control. The landing zone for EFT-1 is about 800 miles south of San Diego and 100 miles west from the tip of Baja California, in international waters. The landing zone has a diameter of five nautical miles, and Generale expects to be at the zone a day ahead of time. NASA will send out a “Notice to Airmen and Mariners” advising them to steer clear of the area. “We don’t want our capsule coming down on a fishing trawler,” Generale said.
He isn’t yet sure exactly how far out of the landing zone the Navy will sit as Orion descends, or the exact moment they will move in, since Safety assessments are still in work. Helicopters will be in the air to spot the capsule and capture high-resolution images of its heat shield before it smacks the water.
Generale said imaging the heat shield prior to impact will allow engineers to assess its performance. The shield is 16 feet in diameter—the largest ever flown. “We are revitalizing some Apollo technology on this heat shield,” he said. It’s a very similar design to what was used on Apollo.”
The helicopters will also be on the lookout for the components Orion will shed as it descends, which includes the forward bay cover, pilot chutes and drogue chutes. “There will be some pieces of hardware in the air with the capsule at the same time,” Generale said. “When those hit the water, our intent is to pick up after ourselves. Our mothers taught us well.”
As Orion approaches the ocean under its 116-foot main parachutes, the spacecraft’s offset center of gravity will cause it to strike the water at a 26-degree angle. This makes the impact more comfortable for the crew, which will absorb the impact along their spines, rather than their backs. Even so, the capsule hits the water at about 20 to 25 miles per hour. “It gives them a pretty good jolt,” Generale said.
When the capsule hits the water, the parachutes will be released. “There’s a guillotine—a pyrotechnically activated blade that cuts through the steel risers and releases them from the capsule,” Generale said. While it is possible for the parachutes to land on the capsule, he said there is usually a breeze at sea to prevent this from happening.
Orion has three landing positions: upright, upside-down or on its side. Upright is known as Stable 1 and is the preferred position. Upside-down is known as Stable 2, and astronauts aren’t big fans of this orientation because “they’re hanging upside down off their couches,” Generale said. To keep Orion right-side-up, a series of bright balloons called CMUS, the Crew Module Uprighting System, automatically inflate from the capsule’s top upon splashdown. “It’s akin to the system that was used on Apollo. Historically, we found that 50% of the time during the Apollo and Skylab missions, the wave and wind condition could be just right to flip the capsule upside down.” There’s also a side position called Stable 3, but getting there entails multiple CMUS failures, which Generale said is unlikely.
The EFT-1 Orion capsule will be refurbished and used later for an ascent abort test at Kennedy Space Center. The spacecraft will launch atop a repurposed Peacekeeper missile first stage and sail out over the Atlantic Ocean, at which point the launch abort system will ignite, testing the capsule’s ability to scramble away from a failing launch vehicle.
As for future Orion capsules, they are, for the most part, not reusable.
“There will be some components that can be re-used—probably some avionics boxes and things like that,” Generale said. “But because of landing in a saltwater environment, we will not be reusing the main structure.”
It has been ten years since NASA announced construction of what was initially known as the Crew Exploration Vehicle. When Orion finally completes its first mission later this year, Generale and the Navy will be the first to welcome it home. In the process, they will recreate a scene that hasn’t played out in American spaceflight for nearly 40 years.
“We’ve had a very good working relationship with the Navy, recreating the relationship we had during Apollo,” he said. “The crews that we’ve worked with have been enthusiastic and helpful and have provided a lot of good information for us. It’s been a joy working with them.”