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(11 September 2020 – NASA Marshall) NASA’s Rapid Analysis and Manufacturing Propulsion Technology project, or RAMPT, is advancing development of an additive manufacturing technique to 3D print rocket engine parts using metal powder and lasers.

The method, called blown powder directed energy deposition, could bring down costs and lead times for producing large, complex engine components like nozzles and combustion chambers. Prior developments in additive manufacturing did not have the large-scale capabilities this emerging technology provides.

Complex designs – such as engine nozzles with integrated channels walls – can be fabricated using blown powder directed energy deposition. The sides of the nozzle and channel walls above are only the thickness of a few pieces of notebook paper. (courtesy: NASA)

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Blown powder directed energy deposition can produce large structures – such as these engine nozzles – cheaper and quicker than traditional fabrication techniques. (courtesy: NASA)

“This technology advancement is significant, as it allows us to produce the most difficult and expensive rocket engine parts for a lower price tag than in the past,” said Drew Hope, manager of NASA’s Game Changing Development Program, which funds the RAMPT project. “Further, it will allow companies within and outside of the aerospace industry to do the same and apply this manufacturing technology to the medical, transportation, and infrastructure industries.”

The printing method injects metal powder into a laser-heated pool of molten metal, or melt pool. The blown powder nozzle and laser optics are integrated into a print-head. This print-head is attached to a robot and moves in a pattern determined by a computer building one layer at a time. The fabrication method has many advantages, including the ability to produce very large pieces – limited only by the size of the room in which they are created. It can also be used to print very complex parts, including engine nozzles with internal coolant channels. Rocket engine nozzles that contain internal coolant channels run cryogenic propellant through the channels to help keep the nozzle at safe temperatures.

“It’s a challenging process to manufacture the nozzles traditionally, and it can take a very long time,” said Paul Gradl, RAMPT co-principal investigator at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “Blown powder directed energy deposition additive manufacturing allows us to create very large-scale components with complex internal features that were not previously possible. We’re able to significantly reduce the time and the cost associated with the fabrication of channel-cooled nozzles and other critical rocket components.”

The RAMPT team recently used the technique to produce one of the largest nozzles NASA has printed, measuring 40 inches in diameter and standing 38 inches tall, with fully integrated cooling channels. This nozzle was fabricated in record time – just 30 days compared with nearly one-year using traditional welding methods – and completion occurred a year earlier than scheduled due to the technology advancing rapidly.

The RAMPT project’s success has garnered the attention of NASA’s Space Launch System, or SLS, rocket team. NASA’s SLS, along with the Orion spacecraft, are the backbone to our deep space exploration plans, including sending the first woman and next man to the Moon in 2024 and establish sustainable exploration by the end of the decade. The SLS Program is investing in RAMPT’s blown powder directed energy deposition fabrication process with the goal of certifying it for spaceflight. Together with RAMPT, the team is using the technique to build and evaluate a channel-cooled nozzle that is up to 5 feet in diameter and almost 7 feet tall.

“Producing channel wall nozzles and other components using this new type of additive manufacturing would enable us to make the SLS engines at the scale required with a reduced schedule and reduced cost,” said Johnny Heflin, Liquid Engines Office manager for the SLS Program.

Through a series of rigorous hot fire tests, engineers will subject a subscale version of the nozzle to the same 6,000-degree combustion temperatures and sustained pressures it would face during launch to demonstrate the durability and performance of the new directed energy deposition technology.

Public-Private Partnerships

While NASA is leading the expedition of technology development, partnerships with academia and industry play an important role. Through an agreement with Auburn University in Alabama, RAMPT collaborates with specialty manufacturing companies already advancing the “state of the art” bolstering their work and making the technologies developed by this team available widely to the private sector. These public-private partnerships also add value to NASA missions, as partners share some development costs.

NASA’s investments in blown powder direct energy deposition fabrication technology and materials development will play a critical role in enabling the agency’s most ambitious exploration missions. The technology may also play critical roles in many other industries, including commercial space, helping make the world a better place one print at a time.

The RAMPT project is funded by NASA’s Game Changing Development program within the Space Technology Mission Directorate. RAMPT includes partners from across the agency, including NASA’s Glenn Research Center in Cleveland, NASA’s Ames Research Center in Silicon Valley, California, industry, and academia.

NASA engineers are exploring a new way to 3D print rocket engine parts using metal powder and lasers. The method, called blown powder directed energy deposition, is faster and more affordable than conventional fabrication methods. The development is part of NASA’s Rapid Analysis and Manufacturing Propulsion Technology, or RAMPT, project. (courtesy: NASA)

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Space

hints of fresh ice in northern hemisphere

hints of fresh ice in northern hemisphere

(18 September 2020 – JPL) New composite images made from NASA’s Cassini spacecraft are the most detailed global infrared views ever produced of Saturn’s moon Enceladus. And data used to build those images provides strong evidence that the northern hemisphere of the moon has been resurfaced with ice from its interior.

Cassini’s Visible and Infrared Mapping Spectrometer (VIMS) collected light reflected off Saturn, its rings and its ten major icy moons – light that is visible to humans as well as infrared light. VIMS then separated the light into its various wavelengths, information that tells scientists more about the makeup of the material reflecting it.

The VIMS data, combined with detailed images captured by Cassini’s Imaging Science Subsystem, were used to make the new global spectral map of Enceladus.

In these detailed infrared images of Saturn’s icy moon Enceladus, reddish areas indicate fresh ice that has been deposited on the surface. (courtesy: NASA/JPL-Caltech/University of Arizona/LPG/CNRS/University of Nantes/Space Science Institute)

Cassini scientists discovered in 2005 that Enceladus – which looks like a highly reflective, bright white snowball to the naked eye – shoots out enormous plumes of ice grains and vapor from an ocean that lies under the icy crust. The new spectral map shows that infrared signals clearly correlate with that geologic activity, which is easily seen at the south pole. That’s where the so-called “tiger stripe” gashes blast ice and vapor from the interior ocean.

But some of the same infrared features also appear in the northern hemisphere. That tells scientists not only that the northern area is covered with fresh ice but that the same kind of geologic activity – a resurfacing of the landscape – has occurred in both hemispheres. The resurfacing in the north may be due either to icy jets or to a more gradual movement of ice through fractures in the crust, from the subsurface ocean to the surface.

“The infrared shows us that the surface of the south pole is young, which is not a surprise because we knew about the jets that blast icy material there,” said Gabriel Tobie, VIMS scientist with the University of Nantes in France and co-author of the new research published in Icarus.

“Now, thanks to these infrared eyes, you can go back in time and say that one large region in the northern hemisphere appears also young and was probably active not that long ago, in geologic timelines.”

Managed by NASA’s Jet Propulsion Laboratory in Southern California, Cassini was an orbiter that observed Saturn for more than 13 years before exhausting its fuel supply. The mission plunged it into the planet’s atmosphere in September 2017, in part to protect Enceladus, which has the potential of holding conditions suitable for life, with its ocean likely heated and churned by hydrothermal vents like those on Earth’s ocean floors.

The Cassini-Huygens mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. JPL, a division of Caltech in Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter.

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Rocket Lab completes final dress rehearsal at Launch Complex 2 ahead of first Electron mission from U.S. soil

Rocket Lab completes final dress rehearsal at Launch Complex 2

(17 September 2020 – Rocket Lab) Rocket Lab has successfully completed a wet dress rehearsal of the Electron vehicle at Rocket Lab Launch Complex 2 (LC-2) at the Mid-Atlantic Regional Spaceport in Wallops Island, Virginia.

With this major milestone complete, the Electron launch vehicle, launch team, and the LC-2 pad systems are now ready for Rocket Lab’s first launch from U.S. soil. The mission is a dedicated launch for the United States Space Force in partnership with the Department of Defense’s Space Test Program and the Space and Missile Systems Center’s Small Launch and Targets Division.

(courtesy: Rocket Lab)

The wet dress rehearsal is a crucial final exercise conducted by the launch team to ensure all systems and procedures are working perfectly ahead of launch day. The Electron launch vehicle was rolled out to the pad, raised vertical and filled with high grade kerosene and liquid oxygen to verify fueling procedures. The launch team then flowed through the integrated countdown to T-0 to carry out the same operations they will undertake on launch day. Before a launch window can be set, NASA is conducting the final development and certification of its Autonomous Flight Termination System (AFTS) software for the mission. This flight will be the first time an AFTS has been has flown from the Mid-Atlantic Regional Spaceport and represents a valuable new capability for the spaceport.

Launch Complex 2 supplements Rocket Lab’s existing site, Launch Complex 1 in New Zealand, from which 14 Electron missions have already launched. The two launch complexes combined can support more than 130 launch opportunities every year to deliver unmatched flexibility for rapid, responsive launch to support a resilient space architecture. Operating two launch complexes in diverse geographic locations provides an unrivalled level of redundancy and assures access to space regardless of disruption to any one launch site.

“Responsive launch is the key to resilience in space and this is what Launch Complex 2 enables,” said Peter Beck, Rocket Lab founder and Chief Executive. “All satellites are vulnerable, be it from accidental or deliberate actions. By operating a proven launch vehicle from two launch sites on opposite sides of the world, Rocket Lab delivers unmatched flexibility and responsiveness for the defense and national security community to quickly replace any disabled satellite. We’re immensely proud to be delivering reliable and flexible launch capability to the U.S. Space Force and the wider defense community as space becomes an increasingly contested domain.”

While the launch team carried out this week’s wet dress rehearsal, construction is nearing completion on the Rocket Lab Integration and Control Facility (ICF) within the Wallops Research Park, adjacent to NASA Wallops Flight Facility Main Base. The ICF houses a launch control center, state-of-the-art payload integration facilities, and a vehicle integration department that enables the processing of multiple Electron vehicles to support multiple launches in rapid succession. The build has been carried out in just a few short months thanks to the tireless support of Virginia Space, Governor Northam, Virginia Secretary of Transportation Shannon Valentine, and Accomack County.

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NASA technology enables precision landing without a pilot

NASA technology enables precision landing without a pilot

(17 September 2020 – NASA) Some of the most interesting places to study in our solar system are found in the most inhospitable environments – but landing on any planetary body is already a risky proposition.

With NASA planning robotic and crewed missions to new locations on the Moon and Mars, avoiding landing on the steep slope of a crater or in a boulder field is critical to helping ensure a safe touch down for surface exploration of other worlds. In order to improve landing safety, NASA is developing and testing a suite of precise landing and hazard-avoidance technologies.

A new suite of lunar landing technologies, called Safe and Precise Landing – Integrated Capabilities Evolution (SPLICE), will enable safer and more accurate lunar landings than ever before. Future Moon missions could use NASA’s advanced SPLICE algorithms and sensors to target landing sites that weren’t possible during the Apollo missions, such as regions with hazardous boulders and nearby shadowed craters. SPLICE technologies could also help land humans on Mars. (courtesy: NASA)

A combination of laser sensors, a camera, a high-speed computer, and sophisticated algorithms will give spacecraft the artificial eyes and analytical capability to find a designated landing area, identify potential hazards, and adjust course to the safest touchdown site. The technologies developed under the Safe and Precise Landing – Integrated Capabilities Evolution (SPLICE) project within the Space Technology Mission Directorate’s Game Changing Development program will eventually make it possible for spacecraft to avoid boulders, craters, and more within landing areas half the size of a football field already targeted as relatively safe.

Three of SPLICE’s four main subsystems will have their first integrated test flight on a Blue Origin New Shepard rocket during an upcoming mission. As the rocket’s booster returns to the ground, after reaching the boundary between Earth’s atmosphere and space, SPLICE’s terrain relative navigation, navigation Doppler lidar, and descent and landing computer will run onboard the booster. Each will operate in the same way they will when approaching the surface of the Moon.

The fourth major SPLICE component, a hazard detection lidar, will be tested in the future via ground and flight tests.

The New Shepard (NS) booster lands after this vehicle’s fifth flight during NS-11 May 2, 2019. (courtesy: Blue Origin)

Following Breadcrumbs

When a site is chosen for exploration, part of the consideration is to ensure enough room for a spacecraft to land. The size of the area, called the landing ellipse, reveals the inexact nature of legacy landing technology. The targeted landing area for Apollo 11 in 1968 was approximately 11 miles by 3 miles, and astronauts piloted the lander. Subsequent robotic missions to Mars were designed for autonomous landings. Viking arrived on the Red Planet 10 years later with a target ellipse of 174 miles by 62 miles.

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The Apollo 11 landing ellipse, shown here, was 11 miles by 3 miles. Precision landing technology will reduce landing area drastically, allowing for multiple missions to land in the same region. (courtesy: NASA)

Technology has improved, and subsequent autonomous landing zones decreased in size. In 2012, the Curiosity rover landing ellipse was down to 12 miles by 4 miles.

Being able to pinpoint a landing site will help future missions target areas for new scientific explorations in locations previously deemed too hazardous for an unpiloted landing. It will also enable advanced supply missions to send cargo and supplies to a single location, rather than spread out over miles.

Each planetary body has its own unique conditions. That’s why “SPLICE is designed to integrate with any spacecraft landing on a planet or moon,” said project manager Ron Sostaric. Based at NASA’s Johnson Space Center in Houston, Sostaric explained the project spans multiple centers across the agency.

“What we’re building is a complete descent and landing system that will work for future Artemis missions to the Moon and can be adapted for Mars,” he said. “Our job is to put the individual components together and make sure that it works as a functioning system.”

Atmospheric conditions might vary, but the process of descent and landing is the same. The SPLICE computer is programmed to activate terrain relative navigation several miles above the ground. The onboard camera photographs the surface, taking up to 10 pictures every second. Those are continuously fed into the computer, which is preloaded with satellite images of the landing field and a database of known landmarks.

Algorithms search the real-time imagery for the known features to determine the spacecraft location and navigate the craft safely to its expected landing point. It’s similar to navigating via landmarks, like buildings, rather than street names.

In the same way, terrain relative navigation identifies where the spacecraft is and sends that information to the guidance and control computer, which is responsible for executing the flight path to the surface. The computer will know approximately when the spacecraft should be nearing its target, almost like laying breadcrumbs and then following them to the final destination.

This process continues until approximately four miles above the surface.

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NASA’s navigation Doppler lidar instrument is comprised of a chassis, containing electro-optic and electronic components, and an optical head with three telescopes. (courtesy: NASA)

Laser Navigation

Knowing the exact position of a spacecraft is essential for the calculations needed to plan and execute a powered descent to precise landing. Midway through the descent, the computer turns on the navigation Doppler lidar to measure velocity and range measurements that further add to the precise navigation information coming from terrain relative navigation. Lidar (light detection and ranging) works in much the same way as a radar but uses light waves instead of radio waves. Three laser beams, each as narrow as a pencil, are pointed toward the ground. The light from these beams bounces off the surface, reflecting back toward the spacecraft.

The travel time and wavelength of that reflected light are used to calculate how far the craft is from the ground, what direction it’s heading, and how fast it’s moving. These calculations are made 20 times per second for all three laser beams and fed into the guidance computer.

Doppler lidar works successfully on Earth. However, Farzin Amzajerdian, the technology’s co-inventor and principal investigator from NASA’s Langley Research Center in Hampton, Virginia, is responsible for addressing the challenges for use in space.

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Langley engineer John Savage inspects a section of the navigation Doppler lidar unit after its manufacture from a block of metal. (courtesy: NASA/David C. Bowman)

“There are still some unknowns about how much signal will come from the surface of the Moon and Mars,” he said. If material on the ground is not very reflective, the signal back to the sensors will be weaker. But Amzajerdian is confident the lidar will outperform radar technology because the laser frequency is orders of magnitude greater than radio waves, which enables far greater precision and more efficient sensing.

The workhorse responsible for managing all of this data is the descent and landing computer. Navigation data from the sensor systems is fed to onboard algorithms, which calculate new pathways for a precise landing.

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SPLICE hardware undergoing preparations for a vacuum chamber test. Three of SPLICE’s four main subsystems will have their first integrated test flight on a Blue Origin New Shepard rocket. (courtesy: NASA)

Computer Powerhouse

The descent and landing computer synchronizes the functions and data management of individual SPLICE components. It must also integrate seamlessly with the other systems on any spacecraft. So, this small computing powerhouse keeps the precision landing technologies from overloading the primary flight computer.

The computational needs identified early on made it clear that existing computers were inadequate. NASA’s high-performance spaceflight computing processor would meet the demand but is still several years from completion. An interim solution was needed to get SPLICE ready for its first suborbital rocket flight test with Blue Origin on its New Shepard rocket. Data from the new computer’s performance will help shape its eventual replacement.

John Carson, the technical integration manager for precision landing, explained that “the surrogate computer has very similar processing technology, which is informing both the future high-speed computer design, as well as future descent and landing computer integration efforts.”

Looking forward, test missions like these will help shape safe landing systems for missions by NASA and commercial providers on the surface of the Moon and other solar system bodies.

“Safely and precisely landing on another world still has many challenges,” said Carson. “There’s no commercial technology yet that you can go out and buy for this. Every future surface mission could use this precision landing capability, so NASA’s meeting that need now. And we’re fostering the transfer and use with our industry partners.”

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