Ernie Fretter, the Arc Jet’s business manager, welcomed a group from the 10th International Planetary Probe Workshop and guided them through the facility. Image credit: NASA Ames / Dominic Hart
"It seems the facility’s history, and sheer size and power, is what impresses our visitors most,” said Michael Wilder, an engineer at the Hypervelocity Free-Flight Facility at Ames. Image credit: NASA
The tour’s final stop was the Ames Space Shop, where guests watched Sarah Hovsepian give a 3D manufacturing demonstration. Image credit: NASAEarly on, NASA’s Ames Research Center, Moffett Field, Calif., broke new ground in all flight regimes, from subsonic to hypersonic, by developing sophisticated test facilities, research aircraft and methods of theoretical aerodynamics. In the fields of planetary exploration and planetary probe technology, it has made some equally impressive contributions to America's space program, including the blunt body concept, which is used on every spacecraft to prevent it from burning up when re-entering Earth’s atmosphere. Ames also played a key role in managing the famed Pioneer planetary spacecraft, the first human-made object to leave the solar system.
These breakthroughs were possible because of the creative and innovative engineering used by Ames employees to develop world-class space exploration technology, including the Arc Jet Complex and Ballistic Range Complex. Both played a key role in determining the aerodynamics and aerothermodynamics of a variety of spacecraft, including those used during the Apollo mission to return astronauts safely from the moon.
To keep the dream of space exploration alive, Ames invited international engineering experts attending the 10th International Planetary Probe Workshop (IPPW-10) at San Jose State University (SJSU), Calif., to tour its research facilities. The workshop was held June 17 – 21 and co-hosted by SJSU and Ames. The visit included a presentation by David Blake, principal investigator of the CheMin instrument on the Mars Science Laboratory Curiosity rover. In addition, guided tours of Ames’ Arc Jet Complex, hypervelocity free-flight facility and the ‘Space Shop’, which features rapid prototyping and 3D printing capabilities, were provided.
The purpose of the workshop was to bring together engineers, technologists, scientists, mission designers, space agency leaders, and students from around the world to focus on exploring solar system destinations during simulated planetary missions on Earth. Ames seemed the most opportune place to encourage enthusiasm and foster interest in planetary probe missions, new technologies, and scientific discoveries among the workshop attendees.
"Ames Research Center is heavily involved in planetary exploration, so we wanted to give others who work actively in this area an opportunity to see the facilities that have enabled so many planetary missions," said Anthony Strawa, the director of the New Opportunities Center at Ames.
The first stop on the tour was the Space Science Auditorium, where Blake discussed the development of the CheMin instrument and its deployment on Mars. He explained the lengthy time it took to develop the CheMin instrument, a definitive mineralogy tool installed on the Curiosity rover used to identify and quantify minerals found on Mars. He explained the competitive project approval processes within NASA, and noted the 20 years’ of grit and perseverance it required to fulfill the project’s goals.
“During 20 years of research and development at Ames, there were 16 instrument proposals and 12 mission proposals written before CheMin was accepted for flight on the Mars Science Laboratory,” informed Blake.
He showed a cartoon illustration of “what it takes” to get your project funded over the years: A hunter said to his dog, “You let the hare get away.” The dog said to the hunter, “I was running for my dinner, he was running for his life.” Researchers need to be like the hare, and show determination and focus to achieve your project goals, said Blake.
After a short question and answer session, visitors moved on to the next stop on the tour, the Interaction Heating Facility (IHF) in Building 238, which is one of four facilities in the Ames Arc Jet Complex. These facilities provide ground-based hyperthermal environments to test thermal protection materials, vehicle structures, aerothermodynamics and hypersonics. Ernie Fretter, the Arc Jet’s business manager, welcomed the group and guided them through the facilities.
IHF testing features were shown and discussed, including its power supply, pressures, enthalpy levels and heat fluxes. His audience then viewed a short video of the aerodynamic heating that occurs on Thermal Protection System (TPS) materials and their responses to a hot gas flow environment (representative of real hyperthermal environments experienced in flight). “TPS samples run in the arc jets from a few minutes to over an hour, from one exposure to multiple exposures of the same sample,” explained Fretter.
The large magnitude and capacity of systems in the Ames Arc Jet Complex make it unique in the world. In development for more than 40 years, it has been used for every NASA Space Transportation and Planetary program, including Apollo, Space Shuttle, Viking, Pioneer-Venus, Galileo, Mars Pathfinder, Stardust, NASP, X-33, X-34, SHARP-B1 and B2, X-37 and Mars Exploration Rovers.
The next stop on the tour was the Hypervelocity Free-Flight (HFF) Range. This facility in particular reflects NASA and Ames’ impressive history of planetary atmospheric entry testing and development. In 1957, the primary test facilities in the branch were ballistic ranges, consisting of light-gas guns that were used to launch small models up to about eight kilometers high per second. Photographs of models in flight are used to measure the model aerodynamics and heating rates. The facility yielded unique data on drag, lift, dynamic stability, boundary layer transition, and hydrodynamic heating at speeds and under conditions not available by any other means. These facilities helped make Ames NASA’s lead center for entry technology.
Today, the HFF consists of the Aerodynamic Facility (HFFAF) and the Gun Development Facility (HFFGDF). The HFFAF is a combined Ballistic Range and Shock-tube Driven Wind Tunnel. The HFFGDF uses the same arsenal of light-gas and powder guns as the HFFAF to accelerate particles that range in size from 3.2mm to 25.4mm (1/8 to 1 inch) diameter to velocities ranging from 0.5 to 8.5 km/s (1,500 to 28,000 feet per second). Most research efforts have focused on Earth atmosphere entry configurations (Mercury, Gemini, Apollo, and Shuttle), planetary entry designs (Viking, Pioneer Venus, Galileo and MSL), and aerobraking.
Michael Wilder, a NASA engineer at the HFF, greeted his guests and guided them through both facilities. These facilities were designed and built in the 1960's to support the Apollo program, and nearly every entry probe or capsule flown by NASA since (as well as commercial vehicles like the SpaceX Dragon capsule) has been tested in this facility. “There aren't many places where you can fly an object at 20 times the speed of sound, indoors,” he said.
A range of questions were asked, such as, “How do you clean the barrel?” and “What would happen if you shot an unstable model?”
Curiosity about others' reaction to such a unique facility also was addressed. “What impresses our visitors most? I think the facility’s history, and sheer size and power of the facility,” said Wilder.
The tour’s final stop was the Ames Space Shop, where guests watched a 3D manufacturing demonstration, from design to production and enhanced digital fabrication. To prepare for a future where parts can be built on-demand in space, Made in Space, the space manufacturing company, has partnered with NASA’s Marshall Space Flight Center to launch the first 3D printer to space.
At the end of the tour, Strawa, thanked people for coming to Ames and hoped they had enjoyed seeing a little slice of history that was so critical to so many of NASA’s successful past exploratory missions.
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