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Astrogram, October 2003

FOR 45 YEARS, AMES PIONEERS NASA SCIENCE AND TECHNOLOGY

*Excerpts from the October 2003 Publication of our Monthly Newsletter
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The Apollo encounter with our moon was one of the defining events of the last century.  Apollo forever changed the way we look at the moon, at the Earth and at NASA.  Anyone over the age of 30 can look up at the moon today and personally remember that 12 men once walked there.  They can recall how thrilling were those late-night, black-and-white images of the small plots of lunar soil around where the lunar landers camped.  For those under 30--and that includes some holding PhDs in space science, and some with star-struck kids of their own--they learned that the last man to have trod the lunar landscape did so before they were even born.  When these youngsters think about the moon and wonder why we have only returned to the moon twice since then, once through a robotic probe developed by NASA researchers at Ames, perhaps they conclude that that early generation of explorers found the moon an even more barren rock than they had imagined.  Apollo changed how we think about our moon.

  When we think about our Earth in our post-Apollo age, by comparison with the moon, we see it as even more life-giving.  Before Apollo, school kids imagined the Earth like a brown Mercator projection lined with political divisions.  After Apollo, we envision the Earth--as first did the Apollo astronauts--as that fragile orb of interlaced green, blue and white suspended in the black vastness of space.  Life on Earth now inspires even more wonderment.   And when we think about NASA, there may also be a generational divide.  Some envision NASA as that can-do team of brainy young men and women--some wearing thick black glasses and others wearing thick white space suits--who achieved what once seemed impossible and did so before that decade was out.  Perhaps others envision NASA as scientists in orange jump-suits, looking down upon Earth while floating free from gravity but simply off to their jobs.   Of course, the story of NASA then, like the story of NASA today, is vastly more complicated and interesting once we look deeper.  And as Ames' life with NASA reaches its 45th anniversary, it is worth exploring how the historical analogy to the Apollo years-and to the early shuttle years--illuminates the 'One NASA' effort of today.  

Ames during Apollo

 

Apollo was a time of sweeping cultural change within NASA.  Yet Ames probably changed the least of all the centers, as the National Advisory Committee for Aeronautics was absorbed into NASA in October 1958 and as NASA became preoccupied with Apollo in 1962. Smith DeFrance kept Ames the way he had built it, as director from its founding in 1939 though his retirement as director in 1966. DeFrance was succeeded as director by H. Julian Allen, a paradigm-shifting aerodynamicist completely imbued with the NACA spirit of relevant but free research.  The first 'A' in NASA stands for aeronautics, and during the Apollo years Ames did much of the work that needed to be done on aircraft so that the new NASA centers could focus on space travel.   Ames still contributed much to NASA's Apollo mission--in terms of science, technology and culture.....   At Ames in the 1960s, as today, most all of NASA's strategic enterprises were pursued--aerospace, information technology, human factors, space and Earth science and aeroflightdynamics.  Each enterprise was weighted  equally by the management of the center and each looked for fertile areas to explore along their borderlands.                                                   

Life Sciences, Information Technology and Aeronautics

 

.....Ames began research on living subjects in the early 1950s when it started building simulators to improve the analog computers behind aircraft controls.  With the birth of NASA in 1958, Ames was asked to invent and build more sophisticated simulators for studying how human pilots could control the coming spacecraft.  From there, Ames developed expertise in the design of space suits that could support life in space while permitting a wide range of functionality.  And Ames began its work in miniature biosensors that could monitor and diagnose the health of astronauts sealed, far away, in space suits and capsules.....   .....Meanwhile, NASA researchers at Ames continued their work on flight simulators--for new generations of piloted spacecraft and rotorcraft and to study human adaptation to long stays in space.....   .....Information technology at Ames started later than the life sciences, though its history also displays the same perambulation.  At first,  the computers  at Ames were mathemeticians, hired to work through equations and compile vast amounts of experimental data.  Ames began using analog computing machines to simulate flight controls, and in the early 1960s, added a few digital computers to compile wind tunnel data and handle administration.  In 1972, Ames acquired the Illiac IV supercomputer, which Harvard Lomax used to create the field of computational fluid dynamics.  Over the next two decades, NASA researchers at Ames bought and debugged almost  every  new generation of supercomputer. ....    

Apollo Technology

  Ames researchers quietly contributed to the Apollo mission. Public attention focused on the spectacular-powerful rockets, massive spaceports, mission control centers and charismatic astronauts. Ames hosted none of these spectacles.  Perhaps the most exciting photographs to emerge from that era, around here, were of tiny capsule models ablaze in a high-speed and high-temperature tunnel or ballistic range.  Instead, behind the scenes, Ames researchers gathered knowledge about new scientific fields  and tested their technologies with painstaking precision.  And they did so with a style that was uniquely Ames.  Researchers with many areas of expertise discussed their work persistently and freely, then cooperated to bring every tool they had to solve a very complex problem.  And they were given the freedom to work quickly and to their own ideal of thoroughness. Ames developed some key Apollo technologies, most importantly technologies to allow the astronauts to return safely to Earth. Building upon what was already two decades of research on re-entry physics and material science--a discipline today known as aerothermodynamics--NASA researchers at Ames devised the basic shape of the Apollo capsule and its thermal protection system.  Today, almost 60 years later, all spacecraft are still derived from essential insights learned at Ames. Before Ames began its work, many thought that a spacecraft re-entering the Earth's atmosphere at meteoric speeds would, like a meteor, burn into a fireball.  Those who speculated about spacecraft design suggested pointy, cone-shape tips of hardened metal to pierce the atmosphere with the least possible friction and the slowest possible melting.  Harvey Allen stepped outside the conventional thought, and took an entirely fresh approach.  (Appropriately, the H. Julian Allen Award is presented each year to the scientists at Ames who do the most creative and relevant basic research.)  In 1948, Allen advanced the blunt-body concept, which was further developed by Al Eggers and Dean Chapman. They conceptualized that, with a blunt body, atmospheric air would still heat up as it crossed the bigger bow shock wave in front of the spacecraft.  However, that air would be heated at a distance from the spacecraft, then pass harmlessly around it and into the wake of gas behind the body.  With less heat near the spacecraft, different types of heatshield materials could be imagined.  Such a radical idea met with resistance, so Ames set about to prove it. Ames then used its practical expertise in wind tunnels and its theoretical expertise in hypersonics and built free-flight tunnels to determine which precise blunt-body shape would be best during re-entry.  These ballistic ranges shot tiny metal models into an onrush of air to reach the actual velocities at which they would enter the atmosphere, while delicate instruments recorded the results.  These test runs led Thomas Canning to discover that the best shape for retaining a laminar boundary layer, and thus minimizing heat transfer to the capsule, was a nearly flat front face to the blunt body.  They also checked these shapes for lift and drag and for aerodynamic stability-so a capsule would not start to tumble.  Based on these tests, NASA selected this shape for the Mercury, Gemini and Apollo capsules.  Once Ames demonstrated which specific blunt-body shape worked best, work began on picking the best materials to protect it.  Since no known materials could insulate against that kind of heat, Morris Rubesin, Constantine Pappas, John Howe and other NASA researchers at Ames developed an ablative heat shield.  Ablation meant that the heat shield material was slowly consumed by burning and vaporization, but as it burned it transfered heat into the atmosphere and away from the underlying metal frame of the spacecraft.  Surface transpiration also reduced skin friction, which kept the spacecraft more aerodynamically stable. Ames people then invented and built arc jet tunnels to prove which were the best specific ablative materials.   Arc jets are a type of wind tunnel that generated very hot gas flows for minutes so that re-entry heat could be simulated both in terms of temperature and chemistry.  Aerospace firms then designed ablative heat shields for the Apollo capsules. These then were tested again by John Lundell, Roy Wakefield, Nick Vojvodich and others in Ames' arc jet complex. The result was superb performance from all the Apollo spacecraft during their re-entry into their home atmosphere.  

Apollo Science

  And upon their return home, the Apollo astronauts had much good information to convey.  Ames had formed a space sciences division in 1962 to maximize all we learned from the Apollo mission.  Ames scientists analyzed samples of rock and soil taken from the moon, studied the lunar craters and measured lunar magnetic fields.   Apollo astronauts spent a total of 340 hours on the lunar surface and carried back to Earth more than 840 pounds of lunar rock.  Only at Ames and JSC did NASA build lunar receiving facilities to analyze soil samples returned from the moon.  JSC would identify and isolate hazardous materials in the samples; Ames would explore the essential composition of the lunar materials.  So Ames built a very clean laboratory and outfitted it with unique equipment.  They observed the carbon chemistry of the samples, and concluded that they did not contain life.  This led them to question what kind of carbon chemistry happens in the absence of life.  They discovered that the moon was being constantly bombarded with solar wind and micrometeorites, which left the moon with a carbon chemistry dominated by the energetic interaction of the sun, the moon and cosmic debris.   Ames space scientists also devised magnetometers to study the moon's composition and its magnetic fields.  Four Apollo missions flew Ames magnetometers to different sites on the surface of the moon, and two portable magnetometers carried aboard the lunar rovers measured magnetic fields while in motion.  These revealed much about the moon's geophysics and geological history.  For example, the moon did not have two-pole magnetism like Earth but did have a stronger field than expected.  They also revealed that the moon was a solid mass, without a molten core like the Earth.  Transient magnetic fields were induced by changes in the solar wind.  Based on this magnetometer data, NASA developed an orbiting satellite to map the permanent lunar magnetic fields, as well as equipment to measure magnetism in other bodies throughout our solar system.   NASA scientists at Ames also devised an ingenious method for doing basic planetary science with what they learned during the re-entry testing of the Apollo spacecraft.  Al Seiff, in a brilliant bit of scientific opportunism, proposed sending small spacecraft to Mars and Venus to gather the first hard data on their atmospheres.  Seiff inverted the re-entry problem.  Rather than developing a new vehicle to better enter Earth's known environment, he proposed dropping a blunt-body vehicle of known aerodynamic characteristics into an unknown atmosphere.  

First, of course, Ames tested the concept.  They started by sending various gases--of the sort that might enshroud other planets--through ballistic ranges and arc-jets to see how blunt bodies reacted to them.  In 1971, Sieff managed the planetary entry experiment test into Earth's atmosphere, to demonstrate that one well-designed probe could gather data on the structure of an upper atmosphere based on aerodynamic responses during hypersonic entry, could directly measure the temperature and pressure of a lower atmosphere once slowed with a parachute, and could gather data about an atmosphere's chemical composition through mass spectroscopy analysis of the hot bow shock wave.  And a probe could telemeter all this data back to NASA before smashing into the planet surface. Working closely with colleagues at JPL, Langley, Goddard and industry, Ames sent probes into the atmospheres of Mars with the Viking in 1976, of Venus with Pioneer Venus in 1978, and Jupiter with Galileo in 1995.  For very little money they returned spectacular data about  the composition of planetary atmospheres.....

RELATED LINKS

Atmosphere of Freedom-Sixty Years at the NASA Ames Research Center excerpts

Searching the Horizon, A History of Ames Research Center 1940-1976 excerpts

Adventures with Apollo excerpts

Astrogram Archive: For 45 Years, Ames Pioneers NASA Science and Technology

Image Archive: Moon Missions

Historic Apollo Press Releases

Clues To Origin Of The Moon Will Come From Study Of The First Lunar Sample

Scientists Will Look For Evidence of Life in Lunar Samples at Ames

 

 

 

 

 

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