Velocity

2014

NovAtel's Annual Journal of GNSS Technology Solutions and Innovation

Issue link: http://velocitymagazine.epubxp.com/i/380251

Contents of this Issue

Navigation

Page 36 of 51

CPAS Orion 2014 For more Solutions visit http://www.novatel.com velocity 37 IN JUST A FEW YEARS, NASA's Orion space- craft will travel further into space than anyone has ever been. This spacecraft will carry up to four astronauts deep into space, where they'll have the opportu- nity to visit near-earth asteroids, the moon, the moons of Mars and eventually Mars itself. Orion's development, which benefits from more than 50 years of spaceflight research, marks a new era of space exploration, with an aircraft that, accord- ing to NASA, "will be the safest, most advanced spacecraft ever built." Orion is scheduled to take its first manned flight into deep space in 2021. But before that can happen, researchers and engineers must complete multiple tests to verify the spacecraft is ready for deep space exploration, from making sure it can withstand the harsh envi- ronment created during launch to ensuring it can safely re-enter the Earth's atmosphere and land in the Pacific Ocean once a mission is complete. Orion's Landing and Recovery System is among those systems that must be verified to ensure the spacecraft is ready to take astronauts into space and bring them home safely. The NASA Capsule Parachute Assembly System, or CPAS, is its subsystem. Through CPAS, NASA has put Orion's parachutes to the test for the last five years. The most recent tests, Nos. 12, 13 and 14 were completed earlier this year. "Our objective is to provide a parachute sys- tem that is going to decelerate the Orion capsule to a safe velocity for touchdown in the ocean," says Charles Williamson, NASA avionics test lead. "We have a whole litany of requirements that we have to meet from the Orion program, and a lot of those requirements were also im- posed on the Apollo program. We have some members of the Apollo program on our team so they can pass down their knowledge. One of the biggest requirements is a descent rate that is less than 33 feet per second to ensure crew members are not harmed when they hit the water." To determine how fast the test vehicle is fall- ing, the team uses NovAtel's SPAN-SE™ receiv- er combined with an inertial measurement unit, or IMU. During these drop tests, researchers need to capture vertical velocity data to ensure the test vehicle's descent rate doesn't exceed the 33 feet per second requirement. The SPAN-SE provides the user interface to NovAtel's SPAN technology, and outputs raw measurement data or solution data over several communication protocols or a removable SD card. Combining the SPAN-SE with a SPAN-supported IMU cre- ates a complete INS system. How CPAS drop tests work The first CPAS development tests focused on one main or one drogue parachute deployed by a static line, but more recent tests have evolved into Cluster Development Tests, or CDTs, that deploy multiple parachutes. CPAS uses two test vehicles, both utilizing SPAN technology. The first is called a parachute com- partment development test vehicle, or PCDTV. When this missile-shaped vehicle drops out of the C-17 aircraft, it falls as fast as possible to test the parachutes' strength. The second option, known as the Parachute Test Vehicle (PVT), was used in January, February and April test launches. Regardless which vehicle is used, SPAN-SE helps ensure analysts vertical velocity data, and has done so in 15 CPAS test drops since the pro- gram began in 2009. The PTV looks like and weighs about the same as the actual Orion capsule so the team can conduct "apple to apple comparisons," but that's about where the similarities end, William- son says. The test vehicle's internal structure is steel and it doesn't come equipped with a heat shield. It is a little shorter than the real Orion so it can fit into the C-17 aircraft, it lands on land rather than in water, and researchers can reuse it for future parachute testing. Before the parachutes are deployed, the C-17 aircraft flies as high as 35,000 feet—the actual altitude parachutes will deploy from on the real Orion spacecraft. The C-17 aircraft is used to recreate the turbulence as the test vehicle falls through the air, and to see how it reacts to that " " Our objective is to provide a parachute system that is going to decelerate the Orion capsule to a safe velocity for touchdown in the ocean. Orion facts • Orion can carry two to six crew members • Orion was named after one of the largest constellations • Crew missions will last between 21 and 210 days • Total change in velocity is 4,920 ft/s • Orion's gross liftoff weight is 69,181 lbs • Orion's effective mass to orbit is 50,231 lbs Source: NASA

Articles in this issue

Links on this page

view archives of Velocity - 2014