Category Archives: Astronomy and Aerospace

Converting NYC’s Central Park into Manhattan Airport

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There is a website by the Manhattan Airport Foundation dedicated to the proposition that Central Park in New York City be converted into a regional airport. From their press release-

NEW YORK, NY, July 15, 2009 – For the past three years The Manhattan Airport Foundation has been quietly laying the groundwork to provide New Yorkers with a most fundamental urban amenity: access to viable air transportation. And today, TMAF releases its much-anticipated Stage One call for entries to a hand-picked group of top architecture firms worldwide in what is sure to be one of the most closely-watched design competitions in recent memory.

This has to be some kind of a joke. What a horrible place for an airport. Even if the people of NYC consent to the loss of a large greenspace in the middle of their high density glass and steel jungle, there is the issue of air traffic. Do these people understand how loud jet aircraft can be? Someone should remind them that Hong Kong was so anxious to be rid of their mid-town airport that they built an artificial island to put it on. Imagine jet traffic lumbering in on final approach over the tops of the buildings in Manhattan? It might even drown out the sound of honking taxis.

Even better, imagine the noise of jets on departure, clawing for altitude at full power trying to get out of the Manhattan airspace? Imagine the the roar of jet engines reflecting off of the skyscrapers from 777’s and other heavies on their takeoff rolls. Power failure on takeoff? The skyscrapers downrange will absorb the impact energy.

Yep, this has to be a gag of some kind. Imagine someone actually trying it? Pffft!

Mineral deposits on other worlds

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As one begins to understand the manner in which mineralization and elemental concentration occurs as a result of terrestrial geology, it is only natural to wonder how this would occur on other worlds. On earth, the concentration of the elements in the form of mineral deposits is a partitioning phenomenon that benefits greatly from fractional crystallization, metamorphic modifications, and from a variety of transport mechanisms.

Fractional crystallization of magmas provides a condition whereby a mixture of simple and complex ions may associate to form mineral compositions that partition from the molten phase by virtue of high solidification temperature. In this way, solid, higher melting compositions precipitate from a melt sequentially, leading to the selective partition of certain combinations of elements into a new solid phase. The molten phase may be enriched in certain combinations of other elements by default- many of which may be relatively volatile.

The composition and cooling rate of the magma will determine the nature of the solid rock that is formed after cooling.  Over time, rock may be lifted toward the surface and subjected to modification by hydrothermal action or by erosion and redeposition by gravity. Cooled igneous rock may be subjected to crystalline modification by exposure to heat further down the timeline.

Hydrothermal water, superheated under high pressure, is a major force in the formation of mineral deposits. The sulfides (and hydrosulfides) of transition metals (i.e., Au) are thought to be transported from source rock through cracks, faults, and porous formations to be deposited in locations where transport can no longer be sustained. The accumulation of economic quantities of uranium are thought to be the result of hydrothermal or aqueous transport as well.

So here is the point of this essay–  If preconcentration of elements to viable deposits is critical for the success of value extraction on earth, what about mining on the moon or Mars? To what extent are we dependent on these mechanisms to make viable the mining and extraction of useful materials?  If lunar geology has not been quietly concentrating minerals in the manner to which we earthlings have been accustomed, how will we come to grips with using native materials on the moon for self-sustaining habitation?

It is one thing to find x ppm of oxygen or y ppm of titanium in the lunar regolith. It is quite another to enable extraction of critical elements from low-value (dilute) material. The chemical energy inputs for processing will be severely limited owing to the scarcity of reducing materials on the moon or Mars. Reducing materials are really just reservoirs of inexpensive and useful electrons. Reducing materials would include carbon or electropositive metals for the reductive winning of other metals. 

In the absence of an inexpensive supply of electrons, all phases of extraterrestrial mining and processing will be subject to large cost multipliers. Cheap electrons are required to energize machinery, move materials, or conduct refining. All of these familiar activities are energy intensive on earth and there is no reason to think it will be different on another world. On earth, cheap electrons come in the form of diesel and coal. On the moon and Mars, it seems likely that solar and nuclear will energize most work for those who try to set up camp there.

Submersible Aviation

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Sharpen your pencils boys and girls. DARPA is soliciting proposals for Submersible Aircraft.  Here is the synopsis-

DARPA is soliciting innovative research proposals on the topic of a Submersible Aircraft. In particular, DARPA is interested in a feasibility study and experiments to prove out the possibility of making an aircraft that can maneuver underwater. The proposal needs to outline a conceptual design along with identifying the major technological limitations that need to be overcome in order to maneuver an aircraft underwater. In addition to the conceptual design studies, performers need to outline experiments or computational models that will be used to demonstrate that the major technological limitations can be overcome.

Aircraft are constructed to withstand loads from particular directions arising from the airstream and from dynamic loads imposed on the airframe by accelerated maneuvers. A submersible aircraft must be constructed to withstand additional compressive loads all over the airframe from all directions due to conducting operations in water and at depth.

Perhaps crew chiefs will have to deal with seaweed and barnacles in addition to damage from FOD and birdstrikes. A whole new skill set will arise for naval aviators. Will these craft require anchors and bilge pumps? It is fun to speculate.

It may well be easier to devise a submersible aircraft carrier. I can see it now–

Sunset in the north Atlantic. A blood red sun sets over the gray Atlantic rollers. Suddenly, the surface is broken by a large craft abruptly surfacing. The bow rises into the air then splashes to the surface as the large gray ship glides onto the surface at full speed.

Moments later, a hatch on the offset conning tower opens and sailors spill onto the broad flat deck.  Large sections of deck open skyward and elevators lift folded aircraft to the deck. These strange craft are rolled into position while scurrying crews fuel and arm them in the muted red running lights. Curling streams of steam spill to aft from vents on the carrier deck as the vessels screws push it forward.

Elsewhere on deck, sailors mount antenna arrays and open ports revealing defensive weapons. Soon, a fleet of submersible men-of-war have surfaced and set up a defensive perimeter around the submersible aircraft carrier.

After a few minutes, the aircrews run toward the aircraft and strap in. Turbine engines begin to whine as they spool up. Crews disconnect startup carts and run with their equipment to designated locations. As the aircraft power up, their wings unfold and lock into place.

Pilots engage the flapping box and the turbine powered ornithopters begin to flap their articulated wings. The pilot of the lead craft advances the throttle and rolls to the takeoff position while exercising control surfaces. The airboss clears the flight for takeoff and the pilot salutes smartly and advances the thrust to military power.

The black stealth gullwing craft diverts full power to the flapping mechanism and leaps into the air, vanishing into the dark sky.  The vacancy is quickly filled by the next craft. Moments later, another takes wing followed by the rest of the squadron.

At altitude the squadron members meet and assume formation flight. Below, the carrier has already begun to submerge to loiter in position until the appointed time where it will surface and recover the flight if any manage to return. It will be a harrowing night.

Siccus Silicis. Oh yonder dessicated moon! Why dust thou taunt me?

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Big discovery. A few doors down at The Universe Today there is a report of findings showing that the moon is quite dry. This result is from an interpretation of radar soundings taken by the Japanese lunar probe SELENE.

Given the near proximity of the sun, and lack of any atmosphere, it would be astonishing that any water would be found on the moon, at least in the top few meters. Perhaps there are mineral hydrates in the regolith, but discrete surface water as ice or liquid in the shadows seems a bit of a stretch. Supposedly a trace of water was found by others near the polar regions where the sun angle is always low. 

Comets famously de-gas when they come near the sun. Maybe the moon was blowing a vapor trail too- 3 or 4 billion years ago.

The SELENE radar soundings were used to infer the presence of aqueous reservoirs well below the surface. The results failed to give any evidence of such bodies of water. Given the tumultuous history of the moon, as evidenced by the lava plains and impact activity it has experienced, there has been lots of opportunity for water to sublimate or cook off through fractures in the regolith in the past.

I like and appreciate the Universe Today site. But if I could offer some constructive criticism, they could do with more links to primary references rather than just recursive links to previous Universe Today articles. Actually, more than a few news sites do this.

On a side note, it is worth browsing the Japanese Space Agency (JAXA) website to get a feel for the depth of their program.

US Airways Splashdown on the Hudson

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The Hudson River touchdown of US Airways flight 1549 has been called a miracle by some folks. How these folks would describe the ingestion of a flock of birds in terms of miraculous phenomena has not been disclosed. Whatever it was, the aircrew certainly performed admirably.

If you look at a map of the flight path and note the timing, one minute after the birdstrike the A320 had descended from 4000′ to 2000′. At this phase of flight 1549, the airplane is heavy with fuel, baggage, and people. They are configured for climbout and are navigating in congested airspace at low altitude.  At least one of the pilots has his head on a swivel watching for traffic while the other is monitoring flight control systems.

After the birdstrike, there would be some seconds of confusion where the pilot and first officer would have to analyze the warning annunciators as well as what story the flight instruments are telling them. Loss of power on climbout means a prompt loss of airspeed. Here the pilot and first officer would coordinate their cockpit duties. One pilot will concentrate on flying the airplane while the other would, for instance, focus on an engine restart, declaring an emergency with the tower or TRACON, notify the cabin crew for emergency procedures, etc.

While the pilots are determining what kinds of flight controls they have to work with and what other failures may be unfolding, they have to establish a standard airspeed that will minimize their decent rate. This gives them more time in the air and correspondingly, more landing options.

An airplane does a coordinated turn by banking the wing and tilting the lift vector in the direction of the turn. As you tilt the wing, the force vector acting against gravity becomes smaller and without coordinated input from other controls and a bit of power, the airplane will begin to sink.

The point is that when you bank an aircraft during a deadstick glide, you will increase the sink rate. Looking at the map, the pilot could not afford to lose anymore altitude by attempting to make a gliding turn to Teterboro to get lined up with the runways. They had no choice but to continue straight forward along the direction of the river and hope they could land in the water without dipping a wing and cartwheeling the airplane.

I’d say the aircrew made a series of good decisions.

Martian Swamp Gas

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According to recent reports, space scientists using infrared spectrometers at observatories in Hawaii and Chile have detected low levels of methane in the Martian atmosphere. This finding is consistent with results from as far back as 2003 when several studies reported methane at approximately 45 ppb.  Observers performing the latest work conclude that the observed methane must be of recent origin, given the short half-life of atmospheric methane due to photodegradation. 

The connection of these findings with the possibility of past or present life on Mars has proven irresistable. I’m sure there are group leaders beavering away at mission proposals this very moment based upon these findings.

An explanation that is much less exciting and much more challenging in regard to grant proposals is the abiotic explanation. Here on earth there we have a lesser known and widely overlooked abiotic theory of hydrocarbon origin. Abiotic hydrocarbons are often referred to as primordial and are known to exist in planetary atmospheres elsewhere.

According to John S. Lewis, Physics and Chemistry of the Solar System, 2nd edition, 2004, Elsevier, Inc.,  p. 159, the mole fraction of methane in the atmosphere of Jupiter is 0.001 and for Saturn it is 0.002.  The mole fractions of water are 0.001 and 0.002 respectively. Among heavy atom species, only ammonia, hydrogen sulfide, neon, and argon approach these levels within a factor of 0.5 to 0.1.

Oxygen and carbon are two of the most highly abundant heavy atoms and to see them richly represented as their respective hydrogen compounds isn’t so surprising.

At some point in the formation of the solar system, atomic carbon and atomic hydrogen were cool enough to collide and form molecular methane.  Hydrogen with its larger mole fraction would be expected to dominate bond forming interactions with carbon atoms, forming H-saturated methane.

Given the abundance of methane in the gas giants (and don’t forget the methane atmosphere of Titan)  it is hard to discount that Mars has trapped methane in the vast interstitial spaces of the interior of the planet. Methane is known to form clathrate structures with water, so perhaps the proposed underground reservoir of Martian water is comingled with methane.

I believe we should be exploring Mars. But I am increasingly uncomfortable with this stream of “Entertainment Tonight” titillation coming from NASA in regard to the possibility of life on Mars.  Perhaps our culture isn’t as advanced as we assume. Space exploration has always had a large political prestige component to it. Contractors need new contracts and politicians are always keen to bring funding to their districts.  If it takes our lesser angels to make it work, then so be it.

Solar Transit of Jet

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Check out this great shot of a jet transiting the sun. It happens ca 8 seconds in the sequence.  What surprised me was the extent of the forward motion of the contrail vapors.  I always imagined that they had closer to a zero ground speed. This is a good visualization of the extent to which the aircraft does work on the atmosphere by accelerating some of it along the direction of motion.

This video was captured by a member of the Radio Jove community. He was shooting a solar prominence with a Coronado PST and a webcam when the jet passed through the field of view. (Obviously, he was not doing radio astronomy at the time.)