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Editing needed to accommodate the new "vision" statement

A seemingly trivial event has revealed some schadenfreude about NASA, along with a lot of irritation.  Apparently (as is their wont) the fertile minds running our national space agency decided that the time has come (once again) for a new and improved vision statement – out with the old and in with something new.  These would be harmless exercises except to the extent that taxpayer money is being spent to no real purpose (but if I got into that, there’d be no end to this post).

I want to specifically address the newest agency vision statement.  It reads: “To reach for new heights and reveal the unknown so that what we do and learn will benefit all humankind.” Beyond being generous, well meaning and philanthropic, what new vision can be found here? Should we not “reach for new heights”?  Isn’t the job of an agency devoted to exploration to “reveal the unknown”?  And why not do all this “for the benefit of all humankind?”  The first order of any lunar return must certainly be to replace that ill-conceived plaque that’s already there – “We came in peace for all mankind.”  Actually, “all kind” has a certain ring about it – perhaps on the next go-around.

I could vent my spleen about the utterly vacuous nature of the new slogan.  I could point out that nothing in it requires NASA (or any other entity) to actually conduct missions into space, or in fact, to do anything at all.  I could find many who, like me, understand that this new slogan reflects the fact that the agency understands that it has no real mission and has employed a wordsmith to design the appropriate phrasing for such a situation.

I have written previously about the management fads that periodically sweep through the agency – the alphabet soup of TQM to Earned Value to Continuous Improvement.  American industrial life is awash with self-help management cults that variously are employed to convince agency personnel they really need to become managers because NASA needs more people to manage meetings and seminars about all of the wonderful things they are going to do in space.  NASA is most certainly not immune to this tendency and indeed often among the first to embrace new management fads as soon they come out of the box.

What does this say about the state of our national space program?  As a longtime student and participant of many things NASA, I feel uncomfortable saying it’s because no one in charge of the agency can say (or cares to say) why we have a space program or what its mission is — or what they would do if they had one.  This is not to say that there aren’t good reasons for a space program or that there aren’t people who work for NASA who do in fact know what they are trying to do.  I believe that NASA dropped the ball in implementing the Vision for Space Exploration because they never took the trouble to understand exactly what it meant – that they forgot about what having a vision means beyond the obvious articulation of some destination.  Clearly, you cannot see a way forward to implement what you do not understand.

Twenty years ago, NASA got a new administrator, someone who (it was fervently hoped) would breathe new life into the moribund organization.  Daniel Goldin was a “take charge” guy, someone who had been successful in the commercial and defense space sector at TRW.  Goldin came to NASA ready to shake things up – he reinstated NASA’s classic Technicolor “meatball” logo and claimed to want to hear all opinions.  I was invited to a “Meet the New Administrator” meeting soon after he took office.  During the meeting, he was thoughtful and listened carefully while about a dozen of us from a variety of backgrounds kicked around some ideas about the mission of NASA.  Then, in the middle of this all-day brainstorming session, he suddenly excused himself and left.   He returned a bit later, breathless and with great excitement, announced to us: “I’ve just spent the last 2 hours with Carl Sagan!”

Uh-oh.  I knew what that meant.  The new “mission” of NASA was to be a “Quest for Life.”  And sure enough, searching for life became the mantra of NASA’s mission under Dan Goldin.  But by making “the search for life” their mission, NASA faced a problem – if they didn’t find it, their mission could be considered a failure.  So, in order to survive the new “mission,” the Quest for Life gradually morphed into the search for water (on Mars).  After all, water is required for life.  So the mission objective mutated from a long-shot miracle to something reasonably certain.  It fit.  No one would be seen as not fulfilling NASA’s mission and they could continue to look for water on Mars and dream of discovering new life.

Anyway, as I said, vision statements come and go.  No doubt the new one will last about as long as the current occupants of NASA Headquarters.

Oh, what was my brilliant suggestion for a “vision statement,” you ask?

“To explore the universe with people and machines.”

Succinct – to the point – all-inclusive.

But what do I know?

New interpretation of the lunar interior (from Weber et al., 2011, Science 331, 309-312)

A recently published science paper presented results of a re-analysis of seismic (moonquake) data sent to the Earth from a network emplaced by the Apollo astronauts 40 years ago.  The scientists processing the old data found that the Moon may have more than a simple core – it may have a layered, partly liquid metallic core.

Why is this important?  Scientists have known for many years that the Earth has a layered interior structure.  The outermost layer, called the crust, is the only part of the Earth directly accessible to us for study.  The crust varies in thickness, ranging from a few kilometers in the ocean basins to over 20 km in continental areas.  The next zone down is called the mantle.  The mantle is very thick – almost 3000 km.  It is made up of a dense, iron- and magnesium-rich rock type called peridotite.  Partial melting in the mantle is the source of basaltic magma that erupts to make up the floors of ocean basins worldwide.  The innermost part of the Earth is the core, comprised mostly of metallic iron and nickel, and over 3000 km in radius.  The outer layer of the core is liquid, but the enormous pressure that contains the inner core keeps it solid.

The Earth’s core is electrically conducting as the rotation of the Earth induces currents within it.  It is thought that these electrical currents are responsible for the dynamo that generates the magnetic field of the Earth.  Because most of the Earth’s iron is contained in the core, we know that in bulk composition, the Earth is made from chondrites, the same stony material found as primitive meteorites in space. Thus, understanding the core is relevant to the origin of its magnetic field and the internal structure and bulk composition of the Earth.

For these reasons, we are interested in the possibility of a core within the Moon.  Even before we went to the Moon, we understood that an internal structure similar to Earth was not likely.  A property called moment of inertia told us in broad terms that, unlike the layered structure of Earth, the Moon was more or less homogeneous inside.  The moment of inertia indicated that any core inside the Moon must be smaller than a couple of hundred kilometers at most (the Moon’s radius is 1740 km).

Seismometers, deployed on the Moon as part of a surface network during the Apollo missions, operated for over seven years collecting data on tremors within the Moon.  Because certain rocks have known physical properties (e.g., density), we use the velocity of seismic waves in an indirect way to infer the presence of these rock types and physical structure.  From our initial analyses of these data, we determined that the Moon had a fairly thick crust (from 50-80 km, more than twice the thickness of Earth’s crust) and a very thick mantle, almost the remainder of the lunar radius.

The question of the existence of a lunar core remained uncertain.  One moonquake resulting from a fairly large impact on the far side of the Moon  a couple of years after the Apollo missions had ended produced a signal that suggested the presence of a small core (less than 400 km radius).  Moreover, because seismic waves come in two varieties – P-waves, or compression (or sound) waves and S-waves (shear waves, which cannot propagate through liquids) – the partial suppression of S-waves through the center of the Moon during this event suggested that the lunar core might be partly liquid.

But this result was so uncertain that few lunar scientists actually believed it.  They proceeded to try and constrain the dimensions and composition of a lunar core through other means.  A core may be important in the generation of an early global magnetic field that some of the lunar samples seems to indicate (the current Moon has no global field).  By carefully measuring the ways in which the magnetic field of the Sun and Earth is modified when the Moon passes through it (as it does during its orbit around the Earth), it was thought that it might be possible to “sense” the presence of a lunar core by measuring these deviations.  Results indicated that the core of the Moon had to be small (less than 400 km in radius) and probably made of iron sulfide (FeS).

After seven years of operation, the Apollo seismic net was turned off to save money.  Up until it was turned off, we had received a large amount of data but processing it was extremely difficult.  The Apollo instruments, although sensitive, were very noisy and not well coupled to bedrock as are seismometers on Earth.   Fortunately, faster and more capable computers, along with new techniques to process and analyze noisy data, were developed.  And a new generation of scientists came forward to re-examine the old seismic data to see if anything could be discerned from it.

The new results are surprisingly detailed.  Not only do these researchers think they have detected a core inside the Moon, but a core with three separate layers – an inner solid core and outer core, very similar in structure to that of the Earth, but with the added wrinkle of a partly molten outermost layer.  The entire core is almost 500 km in radius, slightly larger than the diameter inferred from deep magnetic sounding.

The presence of currently molten core inside the Moon is rather startling; even the earlier idea about a partly molten zone was viewed askance by most lunar students.  But this new idea has revived concepts about a magnetic core dynamo inside the Moon, generating a global field early in lunar history.  Such a dynamo might explain a lot about the remnant magnetic fields measured in some of the returned lunar rocks.  But there is no obvious reason why such a field would suddenly stop being generated.

Even though the old Apollo network data may still be mined for information, to fully understand lunar structure and history we must emplace a long-lived, global network of new instruments to fully characterize the interior of the Moon.  Although studies are underway to determine how this might be accomplished, deployment of such a network is difficult to achieve by robotic spacecraft alone and long life on the Moon may require a nuclear power supply.  Each and every time we start believing that we understand our Moon, a new discovery raises even more questions.