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Prologue: I want to give my bona fides on appreciation of the “US space program.” For as long as I can remember I have been a space enthusiast. I followed projects Mercury, Gemini, Apollo, Skylab, X-15, Space Shuttle, ISS, Voyager’s 1 & 2, Cassini and others in real time. Even though space publicists mention scientific research, they never go into more than the very least they can get away with for fear of MEGO- My Eyes Glaze Over. To its credit NASA posts annual lists of research papers with links disclosing research results from R&D conducted in the orbital environment. Here is such a list. Much of the research might seem arcane but it is important to realize that the practical value is likely to come later as others incorporate it into their subsequent research and product development. This is how R&D works.
A few words about Elon Musk’s plans on moving mankind to Mars. As everyone knows, Musk is actively engaged in developing space craft large enough, numerous enough and powerful enough to take a great many people to Mars. His stated dream for humanity is to transport a large number of people to the red planet to establish a permanent settlement- a sort of Earth 2.0 for humans. There is even fanciful talk of terraforming Mars for more convenient and safer occupation. This is a colossal job, even for a small world like Mars.
All energy produced and consumed on Mars will be electrical via nuclear energy, solar, or maybe wind (??) generation. Combustion as we know it is out due to the absence of combustible materials and abundant oxygen. Solar power generation will be limited by reduced solar energy shining on Mars and by the practical problem of dust accumulation. Thermoelectric generation from a Radioisotope Thermoelectric Generator (RTG) has been the solution used on many Mars landers and deep space probes.
The best radioisotopes for RTG are alpha emitters. Alpha particles are +2 charged helium nuclei which cause a large amount of ionization over a short distance as it crams its way through matter, stopping in a short distance. Because they lose energy over short distances even in air, alphas require very little shielding, unlike beta and especially gamma radiation.
Betas themselves are easily shielded, but as they decelerate in matter, they can generate radiation called braking radiation, or bremsstrahlung x-rays, which are more penetrating. This is how x-rays are generated in an x-ray tube. Electrons impacting a target like copper generates x-rays. The effect is more pronounced in higher atomic number (high Z) elements like copper, but in low Z materials like plexiglass x-ray generation is much reduced. Consequently, beta emitters are commonly shielded with plexiglass.
The main downside to RTG is the low efficiency in converting thermal energy to electrical energy via the Seebeck effect– about 3-5 % currently according to most sources. So, for every 100 watts of thermal energy production, only 3-5 watts of electrical energy are available. This puts pressure on the supply of scarce radioisotopes.
On the good side of RTGs, they are stable, reliable and long lasting. Waste heat can be used to provide warmth for proper operating temperature in the craft or facility. The Mars lander Curiosity uses 4.8 kg of 238PuO2 to produce 100 watts of electrical power.
The deal with the devil you have to make with RTG power generation is that the best heat generating isotopes in terms of power density (watts/g) also have the shortest half-lives. For instance, 210-Po has a high power density of 140 watts/g but a half-life of only 0.38 years. It undergoes a 5.6 MeV alpha decay directly to stable 206-Pb, emitting a gamma only once in 100,000 alpha decays. Gamma emission poses shielding weight penalties and radiation hazards both in manufacture and operation in space. Even with no humans around, there is still the matter of electronic components that are sensitive to radiation. The more commonly used alpha emitter 238-Pu has a lower power density of 0.54 watts/g but a reasonably lengthy half-life of 87.7 years and minimal shielding requirements.
The background radiation environment in space by itself demands that shielding and radiation hardened electronics be used. Any added radiation from an on-board RTG only compounds the problem. The amount of shielding any given material provides is measured in half-thickness, not “full thickness” and is dependent on the type and energy of the particle. This value is the thickness of a specific material required to reduce the intensity to half of the incident radiation, not the total radiation emerging from the shielding material. This is because scattering can occur within the shielding material contributing to or minimizing the total flux. The point of this is that shielding only attenuates radiation to acceptable levels and not to zero.
238-Pu is a synthetic isotope that must be isolated from other Pu isotopes as well as a dog’s lunch of other elements in spent nuclear fuel or be selectively synthesized by nuclear chemistry. Isotopic separation of 238-Pu from other plutonium isotopes is difficult, slow and not the preferred method of producing it at scale. Nuclear chemistry that provides exclusively 238-Pu from a single transformation as with like 237-Np, offers a more productive route. This allows good old regular, valence-electron chemistry to effect the separation needed.
238-Pu is produced by neutron irradiation of 237-Np producing transient 238-Np with its 2-day half-life and subsequent beta decay to the 238-Pu. Chemical separation of the plutonium from residual neptunium is straightforward but, like all chemistry with radioisotopes, burdened by the need for radiation shielding for safety.
238-Pu is presently in short supply in the US. The Savannah River Site was producing “bulk” 238-Pu but was shut down in 1988. After closing of Savannah, the US purchased 238-Pu from Russia but the word is that Russia is short on it as well. In recent years other sites have been scaling up production where “scaling up” means producing in the several hundred grams to a few kilograms in a campaign.
In the RTG, plutonium is not used in the metallic state but as the oxide which is a ceramic or refractory** material like most heavy metal oxides. The plutonium is oxidized to 238PuO2, pelletized and clad in corrosion resistant iridium. According to NASA, this refractory form of plutonium is resistant to an accidental release in a variety of accident scenarios including Earth reentry and rocket propellant fires.
The Seebeck effect is not the only means of producing electrical energy from radioactive decay heat. The free piston Stirling Radioisotope Generator can use decay heat to drive a piston in a Stirling engine using helium gas as the working fluid. Waste heat is dumped at the cooled end of the engine and the linear reciprocating motion of the free piston is used to generate electrical power in the adjacent alternator.
The electric alternator is similar to the electromagnetic flashlight on the market. It works on the ordinary induction principle buy moving a magnet through a coil. You shake the flashlight to recharge it, causing the internal magnet to move back and forth through a coil. Shake it for 1 minute to get 4 minutes of light. The Stirling radioisotope free piston linear alternator operating in this manner can produce 4 times the electrical power of an RGT.
In 2020 workers Wong and Wilson at the NASA Glenn Research Center reported that they were able to operate a Stirling radioisotope power convertor for 14 years maintenance-free.
Off we go!
Some thought will be needed on screening potential migrants to Mars for age, various physical ailments, dental health, genetic predispositions, sociability and underlying psychological issues. A manic crew member could drive fellow crew members to a murderous rage over time. Such screening has been done with astronauts for a long time. I wonder if choosing to migrate to Mars isn’t a sign of some precarious psychological condition in itself, after all the likelihood of a return to Earth may be slim. It would resemble going to jail in some ways.
Over time, the masses of new Martians living in Muskville will have to decide on what to do with themselves beyond exploratory geology, meteorology and engineering studies of Martian accommodations. Mars is a big, arid and frigid desert with no breathable air. But it may offer a few choices for recreation such as spacesuit hiking and shuffleboard. The outdoor choices will be limited by the Muskvillager’s battery, heating and oxygen supplies as well as ability to get around.
Eventually, all manner of psychological, social and physical maladies will manifest in Muskville and will have to be dealt with. People will spontaneously form cliques eventually giving us-vs-them issues requiring mediation. Unless the New Martian settlers are sterilized, pregnancy is a near certainty. An entire book could be written on complications this would bring. The alternative is to limit the inhabitants to a single gender or to gay individuals- most likely a non-starter.
Death on Mars means that your remains will need to rest somewhere outside the facility. A fresh body will freeze stiff in the Martian cold and remain that way indefinitely. Digging a grave will require energy expenditure and digging tools. Cremation will consume considerable power and may be out of reach.
Something like a hospital with medical supplies and trained staff will have to be present. The few physicians who might be present will be required to be generalists with exceptional diagnostic and surgical skills. A full medicine cabinet to cover a range of maladies will be needed to support this.
As Muskvillagers age out, the range of health problems will widen and require care. Diabetes, cancer, dementia etc. will fade in and people will age and die. This will leave job openings and duties behind which will have to be filled.
In general, the conveniences of modern living will be seriously cut short for the New Martians for a long time. A supply line with Earth that can withstand politics, business failure and war must be maintained.
If I were planning a migration to Mars, I’d worry about maintenance and spare parts for everything. Mechanical things will break. Perhaps an orange-colored Home Depot module will hitched to the back of the lander and sent along with a load of duct tape, assorted bolts and screws, sealant, O-rings, hand tools and cleaning supplies. Don’t forget a few bags of peanut M&Ms.
Wherein I jump to conclusions.
The human capacity for folly knows no bound. Woven in with folly are variable education, emotional inputs and diverse belief systems. The migrants will carry religious and political predispositions that they may or may not reveal in screening for candidates. Friends and relatives on Earth will sicken, age and eventually die but access to a return trip to earth may be severely restricted or effectively impossible.
On reflection, establishing even a modest Mars base will involve large energy inputs. Getting to the surface of Mars with enough reserve propellant for the return trip, the establishment of shelter, oxygen and water supplies are the priorities. Beyond just surviving day-to-day, there is interest in the possibility of putting Martian minerals to use as building materials or even water and oxygen production.
There are indications of frozen water on the surface of Mars in certain limited locations. Where there is water there is the possibility of using electric power to produce oxygen. The hydrogen produced may have utility somewhere but its use for combustion seems unlikely due to the corresponding amount of oxygen needed.
Anywhere you have silicates, aluminates and metal oxides, you have oxygen. Silicon and aluminum both have a strong affinity for oxygen and as such represent a thermodynamic well requiring steep energy inputs for oxygen extraction from minerals. Even worse, many silicates and aluminates are oligomers, chain polymers or network polymers that render them insoluble solids with high melting points. Silicates, aluminates and metal oxides are all comprised of a central atom- silicon, aluminum, or a metal -that are electron deficient by virtue of being connected to oxygen anions. In order to liberate oxide from oxidized silicon, aluminum or a metal, something negatively charged needs to come in and displace the oxide species. Metal oxides like the iron oxides are very often refractory requiring high temperatures to react. Then there is a long list of oxyanions like sulfate, phosphate, hydroxide, chromate, ferrates, molybdates, titanates, tungstates, manganates, etc., each with metal cations. After these there are the polyoxyanions …
The point is that there are a wide variety of oxide species to be found in rock and soil with differing properties. In the end, a negatively charged oxide anion must be oxidized to produce molecular oxygen.
A thermodynamic well resides in a substance where atoms come together to form strong chemical bonds and release a great deal of heat into the surroundings. The same amount of energy that was released is minimally what would be needed to drive the reaction in the reverse direction. This bond forming heat energy is dispersed amongst the large number of surrounding molecules. The heat evolved in forming the original bond produces a high temperature locally, but as it spreads out each succeeding layer of neighboring molecules gets a smaller and smaller share of the original energy. As the bond forming energy release is spread over more and more molecules, the resulting temperature rise of the succeeding layers get smaller and smaller.
Newton’s Law of Cooling says that rate of heat flow is directly proportional to the temperature difference between contacting objects. The greater the temperature difference, the more useful work (heat and work are both energy) that can be done. Large temperature differences transfer large quantities of energy. Low temperature differences result in less energy transferred. As the heat spreads to the surroundings it produces decreasing temperatures as the heat conducts away and the ability to do work diminishes. This constrains the recovery of waste heat.
The diffusion of energy in this manner is what entropy is about- the irreversible loss of energy to the surroundings. If you are tempted to talk about entropy, consider that it has to be consistent with its unit of measure: Entropy, S, equals energy per degree Kelvin or Joules/Kelvin (J/K).
In order to get molecular oxygen from minerals it will require a great deal of energy expenditure per kilogram of oxygen. Not only that but specialized equipment and chemicals. Any oxygen produced will have to purified and compressed into cylinders.
MOXIE
The extraction of molecular oxygen from the abundant carbon dioxide atmosphere seems desirable and has actually been put to the test on Mars. A prototype molecular oxygen generator called MOXIE went to Mars on the Perseverance rover and successfully produced oxygen from carbon dioxide beginning in 2021.
The MOXIE oxygen generator is a solid oxide electrolysis device that operates at 800 oC and uses a stack of scandia stabilized zirconia ceramic electrolyte. An excellent source of information on MOXIE can be found at this Science site.
About 10 % yttria (Y2O3) or scandia (Sc2O3) will prevent the zirconia (Zr2O4) electrolyte from undergoing a phase change that causes the ceramic to fail at high temperature. From personal experience I know that scandia is chosen as a better diluent for zirconia because it allows lower temperature operation than yttria by perhaps 200 oC. The lower operating temperature with scandia allows for better sealing of the cell. High temperature seals are very problematic at these operating temperatures.
The MOXIE electrolysis cell uses a nickel coated cathode for reduction of the CO2, a ceramic zirconia/scandia electrolyte that allows oxygen anions to selectively pass through, and an anode where the anions are oxidized and combine to form O2 where it is captured. MOXIE produced O2 at a rate of 6-8 g/hr while on Mars. The process vents carbon monoxide waste as well as unreacted CO2 at the cathode where it is vented.
A limiting factor in operating MOXIE is the operating voltage across the cathode and anode. Two kinds of chemistry can occur within MOXIE. Carbon dioxide can be reduced to form oxide or carbon, depending on the flow rate of CO2 and the operating voltage. The Nernst voltage, VN, is the minimum voltage necessary to do the chemistry. At about 1.1 volts the cell will reduce CO waste biproduct to carbon on the cathode. This is called “coking”. Carbon formation on the cathode impedes the function of the cathode and reduces the output of the cell. The voltage for coking varies very little with flow rate.
The VN for the desired reduction of CO2 to oxide (O–) and CO at a low flow rate is around 1.0 volts and at high flow rates drops to about 0.95 volts or just a bit lower. So, the “normal” operating voltage range then would be between 1.0 and 1.1 volts to prevent fouling the cathode with coke. The operating voltage window seems a bit narrow. It was found that while a stable operating voltage could be supplied, the resistance of the cell was very sensitive to temperature making stable operation a bit delicate.
Pyrochemistry
Extraction of oxygen from lunar mineral samples has been done previously (below). All of the mineral samples were iron rich and gave yields of 2 to 5 % in the form of water. The samples were from Apollo 17 and consisted of ilmenite (FeTiO3), basalt, soil and volcanic glass. The process uses hydrogen at a reaction temperature of 1050 oC producing H2O. Presumably the water vapor is mixed with hydrogen during and after the reaction. The water can be isolated by simple condensation in the presence of the hydrogen.
Reduction of Ilmenite: FeTiO3 + H2 — > Fe + TiO2 + H2O
by Carlton C. Allen
Lockheed Martin Engineering and Sciences Co.
To use the process described above, high temperature is required for the hydrogen reduction in a refractory vessel. This requires considerable electrical energy input to heat the thermal mass of the vessel and the regolith. Spent material will have to be removed and discarded. Perhaps the heat can be recovered for general facility heating. Oh yes, the recovered water will need to be electrolyzed to produce molecular oxygen and hydrogen. This process will use plenty of electric power as well as for the compressors to store the O2 in pressure bottles. In principle the hydrogen can be recovered for reuse in the hydrogenation vessel.
The above process applied to ilmenite produces metallic iron and titanium dioxide, a white pigment. FYI, ilmenite is a common raw material for high purity titanium dioxide production. It is high purity because the titanium dioxide is prepared from titanium tetrachloride which is isolated by distillation from the ore matrix after fluidized bed chlorination.
The first Martian settlers will have to bring every single thing necessary to live on the planet. That includes launching it and landing it on the surface intact. Landing on Mars is tricky because the atmosphere is too thin to provide much aerobraking. The Martian surface pressure is the same as the Earth’s at 80,000 ft altitude and the temperatures are frigid.
Let’s say we successfully land a crew and set up housekeeping. What are they going to do with their time? These missions are supposed to last about 2 years including a lengthy transit time. They can collect various kinds of data on Martian geology and weather and send it back to earth. Somebody will get publications out of it. Eventually, somebody will decide that there must be other things to do besides geology and meteorology. Naturally there will be much ongoing R&D on the pragmatics of living on a remote Martian outpost in a crowded pressure can.
Eventually, the question of what non-research living will look like. Shelter will need construction from some kind of materials. Every new section of shelter will need to be airtight and equipped with environmental controls, sanitation and power. Bulkheads between sections will need to be in place to isolate calamities.
Support staff will be needed one day to provide critical services and perform facilities maintenance. This would also include medical staff, emergency care, food & sanitary support, electronics and IT support and administrative staff for the inevitable paperwork. The lander will need rocket engineers for upkeep and repairs to assure launch reliability for the return trip. Do rockets exist that can sit for a year fueled and then reliably launch and insert into a trajectory back to Earth? There are many, many problems to be resolved in many areas.
After some period of time, a crime will happen on Mars. It could be petty theft, assault or even murder. Someone will have to be appointed to look after law and order. An astronaut-sheriff, sergeant at arms or just the po-leese. What kind of due process will be available to a suspect in a Martian colony? Guns will be too risky to have in the settlement given that a bullet could pass right through a bad guy and rip through the structure creating a leak.
On earth, doing independent research requires getting academic credentials, finding a position, grading exams for goddammed freshman chemistry, executing an R&D program, and then going home every day to refresh and have a social life. Imbedded in all of this we have courtships, marriage, mortgages, babies and divorce. We manage the ten thousand details of modern life and interact with our families and social networks. We mourn those we lose and celebrate our achievements. We enjoy good health and suffer injury and sickness and eventual death.
On Mars, the equation will be a bit different. Many of the above life elements will apply, but from a great distance. Instead, we will be confined to a small space with an unchanging group of fellow crew members. The distance to Earth from Mars is constantly changing and there will be a period absent any communication when the earth is behind the sun.
Eventually, research on living in space or on Mars will wind down to minutae if it hasn’t already and people will have to find other things to do. The funding for living off-world will have to switch from R&D to … what, a lifestyle?
I wonder if there will ever be room for commerce and jobs on Mars. I can see running a canteen or restaurant for profit but stocking them with earth supplies will be prohibitively expensive and infrequent.
What joy can there be living in a pressure can on a hostile planet? What few hermit-astronauts there may be might find it acceptable if they never need a dentist. Perhaps dentures or implants should be routinely fitted to all visitors to Mars.
The second stage of Mars exploration will have to ramp up progress on sustainability. Using Martian soil as raw materials for construction and for crops. As the Martian population rises beyond the first few rotating crews, what will the immigrants do with their time in can-living on a hostile world? Would going to Mars to lead an utterly confined life with nothing to do be an attractive draw?
Epilog
I think that settling on Mars is not such a great idea overall and specifically would be wasteful of resources that should be applied to the rehabilitation of the biosphere on our home world. It would somewhat resemble living on the Amundson-Scott Station on the south pole but without the benefits of breathable air or supplies regularly shipped in. Further, the lack of radiation shielding on the surface of Mars will offer 40-50 times the background radiation as on Earth, not counting the occasional storm of angry solar protons the sun flings out now and then.
** NASA does not use the terms “ceramic or refractory” in its description of the 238-Pu heat source. This is my choice of words.
As I approach retirement in a year or so, I’m overcome with intrusive thoughts as I inventory my accomplishments and failures. Questions like “what have I done with my life?” or “why the hell did I do that?” are dangling in my consciousness more than usual. It’s normal sentient-being stuff I suppose. I never had the impression that farm animals agonized over such things. One lucky benefit of being a bovine.
I find myself disappointed over not having chosen a career path that might have led to a more impactful life. The closest I got was as a chemistry prof helping students get through organic chemistry. It was very satisfying and I managed to meet many wonderful students and faculty. Chemical science has provided a comfortable and intellectually stimulating lifestyle. One negative I suppose is that a chemist isn’t much good without an institution from which to practice chemistry within. Outside of an organization with no lab and no free access to Chemical Abstracts, how is a person to remain connected to chemistry? I guess you just don’t. Some say that a I could be an adjunct prof somewhere. But that is just being a hired hand in a school too cheap to pay much. I wouldn’t be surprised if they picked up adjuncts at Home Depot early in the morning for day labor. The poor sods would load up in the back of an old Ford pickup and trundle off with their sack lunches.
One of my faults as a person is a deficiency in recreation and doing vacations. The fact is that I’m perfectly happy at home reading or watching YouTube videos on geology, writing this silly blog, war reporting on Ukraine or following Itchy Boots. The problem is that guys who don’t stay active during retirement tend to die soon thereafter. I’m not ready to croak just yet so I decided to stay on for another year.
My memory begins in the early 1960’s. One of my earliest memories is watching the funeral of JFK on black and white television. Up until age 14 most of my time was spent on a hog, corn and soybean farm in Iowa. I grew up very aware of the US space program on television and was captivated by it. My father was a private pilot/farmer so airplanes were in our lives. I recall him in his friend Daryl’s Stearman buzzing our farm. They would drop a roll of toilet paper producing a long streamer of paper sailing to the ground and then fly back to the airport. We would go to flight breakfasts at the local airport where we would feast on pancakes, sausage and scrambled eggs inside someone’s hanger. Afterwards they gave kids airplane rides for a penny a pound.
My family still used machines like the corn picker above when I was a kid. For a kid interested in space, these machines made fantastic spaceships of the imagination when sitting in the machine shed. Why didn’t I try to be an astronaut? I did, sort of. I got a pilots license then entered Air Force ROTC in college in 1980. Between nearsightedness and a superabundance of qualified candidates with perfect vision from the Air Force Academy down in the Springs, the odds looked poor. My civilian pilots license was sneered at and valued as less than nothing, but I could train to be the GIB- Guy In Back, handling weapons systems and electronic countermeasures. While blowing things up could be exciting, what do you do when you get out? Naah.
Instead they tried to funnel most of us off into some missile squadron up at F.E. Warren AFB in Cheyenne, WY. It is an honorable slot for many good Americans, just not me. I lived an hour from there and had no interest in southeastern Wyoming or the Dakotas. There would be long stretches underground with someone authorized to shoot you if they doubt your sanity. The whole point of missileer training was to get the launch orders confirmed and the bird launched before the silo got cratered when Soviet MIRVs came sailing in from over the north pole. You can drive by missile silos in northeastern Colorado. Just don’t linger at the fence or a USAF vehicle with armed military police will pull up with considerable urgency and ask just exactly WTF you are doing.
A civilian commercial airline flying career in the 1970’s was complicated by the number of retired Viet Nam pilots who dominated the flying slots at the airlines, or so I was told. They had turbine engine time in complex, very fast aircraft and I had time with a 100 hp Lycoming horizontally opposed 4-cylinder engine poking holes in the sky at 95 knots. I was overly concerned about this I think.
Anyway, organic chemistry captured my fancy and I went for it. This was a constructive career whereas blowing things up was destructive. I chose the former.
Here in Colorado, we were located north of the totality band in the partial annular eclipse region that swept across the US last week. I’ve seen annular eclipses previously so it was a been-there-done-that event for me. Below is a great photograph from NASA showing the eclipse from the DSCOVR (Deep Space Climate Observatory), a satellite jointly operated by USAF, NASA and NOAA. This satellite is in a non-repeating Lissajous orbit at the Lagrange point L1 about 1.6 million kilometers from Earth. It has also been called a looping halo orbit. At this location, it has a perpetual fully illuminated view of the Earth which rotates below it. The exception would be when the moon is in this part of its orbit.
The probe carries numerous sensors to allow measurements of the earth and space environments.
The band of totality stretched across the southwestern states October 14, 2023.
Lagrange points arise from two large masses in gravitational proximity, in this case the sun and the Earth. Relative to the two large masses the 5 Lagrange points allow for stable “parking orbits” for small objects like a satellite. Objects are placed in orbit around the Lagrange points to remain roughly stationary in relation to the Earth-Sun system.
According to Wikipedia, a Lissajous orbit differs from a halo orbit in that it is quasi-periodic and dynamically unstable, needing occasional station-keeping actions by the probe. A halo orbit about a Lagrange point is described as a periodic, 3-dimensional orbit.
The history of the probe is a bit odd. It was launched by SpaceX on a Falcon 9 v1.1 launch vehicle on 11 February 2015, from Cape Canaveral. DSCOVR, initially called Triana after Rodrigo de Triana, the first European explorer to see the Americas. The mission began as a proposal by Vice President Al Gore in 1998 as a whole earth observatory at the L1 point. The probe’s mission was put on hold by the Bush Administration in January 2001 and officially terminated by NASA in 2005. The probe was placed in nitrogen blanketed storage until it was again funded, then removed and tested for viability in November 2008. The Obama Administration funded it for refurbishment in 2009 and the mission was fully funded by 2012. The Air Force allocated funds in 2012 for its launch and awarded SpaceX the contract. On February 11, 2015, the probe was finally launched from Cape Canaveral, FL. Management of DSCOVR is provided by NASA’s Goddard Spaceflight Center.
The NISTAR instrument on board the DSCOVR probe was provided by the National Institute of Standards and Technology, NIST. NISTAR is a 4-band cavity radiometer and is located as shown below in orange. It measures reflected and emitted light in the infrared, visible and ultraviolet parts of the spectrum. The instrument is able to separate reflected light from Earth’s radiant emissions.
The Faraday Cup (FC) is a sensor that collects and quantifies the flux of positively charged particles in the solar wind, i.e., protons and helium nuclei. Variations in the solar wind speed are observed. In the course of operation they discovered that the solar wind is “colder” than was previously thought in terms of what is referred to as “thermal speed.” The researchers presented thermal speed numbers on the order of 300 to 500 km/sec.
Schematic of optical system of EPIC.
- 1SciGlob Instruments & Services LLC, Elkridge, MD, United States
- 2Goddard Space Flight Center, NASA, Greenbelt, MD, United States
- 3LuftBlick, Innsbruck, Austria
- 4Science Systems and Applications, Inc., Lanham, MD, United States
- 5Joint Center for Earth Systems Technology, Baltimore, MD, United States
The probe has a 420 kg dry mass and its solar panels provided an initial 600 watts at 28 volts. The probe attitude and translational motion is managed with a set of 4 reaction wheels and 10 hydrazine thrusters. The hydrazine, N2H4, monopropellant is decomposed over a bed of catalyst prior to ejection. This decomposition yields hot N2, H2 and NH3 gases.
Like many satellites, DSCOVR uses reaction wheels for attitude control. Of the 4 reaction wheels, 3 are for axis-control and the 4th is used as a spare. Each wheel is driven by an electric motor. When the angular velocity of a single reaction wheel changes, there is a proportional counter rotation, resulting in a change in attitude about that 1 axis. Since the wheel velocity can be precisely controlled by the electric motor, fine adjustments in attitude can be attained.
Recently I had the occasion to take a ride in a vintage Fort Tri-Motor aircraft operated by the Experimental Aircraft Association, EAA. Among many other things they take it upon themselves to maintain and circulate certain aircraft around the country for display and to offer rides. The whole enterprise is about promoting civilian aviation and encouraging youth to pursue a career in aviation. The best way to generate enthusiasm is to give rides. This visit was sponsored by the local chapter of the EAA.
This transport aircraft is a 3-engine, high wing tail dragger. The skin is made of a corrugated aluminum alloy covering an all-metal frame. The Tri-Motor has all metal control surfaces which was unusual for the time. The corrugation serves as a stiffener but does increase the drag a bit. From 1925 to mid-1933, the Ford Company produced 199 copies. Ford stopped production in favor of more profitable opportunities. The EAA Tri-Motor is a 1929 Ford 4-AT-E with serial number 69. According to Wikipedia, there are currently 8 Tri-Motors with Airworthiness Certificates. and another 5 under restoration.
The two outboard radial engines each had engine instruments located just above the cowling for “easy” viewing. Evidently this was a concession to practicality and avoided the problem of routing cables and tubes to the cockpit. In those days, avionics were just a twinkle in the designer’s eyes and were largely mechanical in nature with cables and tubes with fluid.
The Tri-Motor gives the visual first impression of being sort of a brick sh** house with fins- sturdy, stable and slow. But, looks hardly matter and we had a great ride from start to finish. It was a calm morning with no convection activity and stable air. Winds were calm and the temperature was ~70 oF. A searing, hot summer day at 5000 ft ground elevation is not the best thing for slow, lumbering aircraft. The density altitude can climb to the equivalent of 9000 feet affording a low rate of climb. There were a few dark scud clouds loitering below the 2000 ft ceiling.
We circled the nearby city and came back on a long final approach. The view from the airplane is quite nice, much like flying in a fish tank. The pilot greased a two-point landing. It’s not a high-performance bird by today’s standards with it’s 93 knot cruise but it could carry 11 paying passengers beginning in the mid 1920’s.
The Tri-Motor was designed to be a reliable transport for passengers and cargo but falls short in the “need for speed” department. One barrier to higher performance in the 20’s and 30’s was a reliance on low compression ratio engines. I say “reliance” because the fuels available then were prone to knocking or pre-detonation if the compression ratio got too high. Knocking or detonation before a piston finishes its compression travel up the cylinder (pre-detonation) could harm an engine and certainly robbed it of power. Aircraft engines are run at constant high rpm compared to automobiles because they have no transmission. As a car accelerates to cruising speed, the gearing is adjusted to maintain optimum rpms on the power band. This allows lower rpm as cruise speed is approached. Aircraft are notable for their lack of a gearshift handle.
The 1920’s were a period of transition in which higher octane fuels were being developed so high engine compression ratios and higher power could be achieved. Tetraethyllead was commercialized in 1924, but was found to be quite toxic to workers in its manufacture.
Early on the development timeline of gasoline engine, it was found that gasoline engines had limitations in power output. One path to higher power output was to increase the compression ratio in the cylinders. Greater piston travel meant more power produced per cycle. Unfortunately, this eventually led to undesired knocking. Incidentally, ignition by compression is how a diesel engine works.
>>> Here is how I wedge chemistry into a post about an airplane. <<<
An interesting article on the history of antiknock additives can be found here and a much better one here. The production of bulk 100 octane aviation fuel was a key factor in the British establishing air superiority over the Luftwaffe in WWII. Across the Atlantic it was none other than Jimmy Doolittle who convinced the US military to convert to higher octane avgas (Incidentally, Doolittle had a Masters and PhD in aeronautics from MIT). In the mid-1920’s Doolittle was pushing seaplanes for the Navy to their limit in speed. He achieved numerous speed records and won many prizes for this. Doolittle would later win acclaim for leading a successful April 18, 1942 bombing raid of Tokyo from an aircraft carrier. Doolittle had a remarkable career and his contributions to many aspects of American aerospace were invaluable.
There were two aspects to manufacturing higher octane fuel at a profit- blending and the manufacture of tetraethyllead. Blending was just a normal refinery operation. Production of tetraethyllead was chemical synthesis to produce an organometallic substance that had to be optimized and scaled up.
Tetraethyllead is synthesized by reacting a sodium-lead alloy with chloroethane- a mixture pretty close to Earth, Air, Fire and Water. The reaction produces tetraethyllead, sodium chloride and unreacted metallic lead. Isolation of product from the reaction mixture is achieved by steam distillation. That tetraethyllead (i.e., something with metal-carbon bonds) is stable in the presence of steam is, in my mind, remarkable. Tetraethyllead is a neutral, hydrophobic substance that is soluble in the hydrocarbon fuel.
Numerous organometallic antiknock additives were found such as the piano-stool complex Methylcyclopentadienyl manganese tricarbonyl (MMT), Ferrocene (the first metallocene), Tetraethyllead, and Iron Pentacarbonyl (Yikes!).
Side note: A serious MMT manufacturing explosion happened in Jacksonville, Florida in Dec. 2007. The blast killed 4 people and injured 14. It was estimated to have been equivalent to 640 kg TNT. Loss of cooling led to a runaway of the batch reaction.
>>> Back to regular programming <<<
Performance specifications straight from Wikipedia.
Original Specifications
- Crew: 3 (pilot, co-pilot, flight attendant)
- Capacity: 11 passengers
- Length: 49 ft 10 in (15.19 m)
- Wingspan: 74 ft 0 in (22.56 m)
- Height: 11 ft 9 in (3.58 m)
- Cabin length: 16 ft 3 in (5 m)
- Cabin width (average): 4 ft 6 in (1 m)
- Cabin height (average): 6 ft 0 in (2 m)
- Cabin volume: 461 cu ft (13 m3)
- Empty weight: 6,500 lb (2,948 kg)
- Gross weight: 10,130 lb (4,595 kg)
- Fuel capacity: 231 US gal (192 imp gal; 874 L)
- Oil capacity: 24 US gal (20 imp gal; 91 L)
- Powerplant: 3 × Wright J-6-9 Whirlwind 9-cylinder air-cooled radial piston engines, 300 hp (220 kW) each for take-off
- Propellers: 2-bladed fixed-pitch propellers
Performance
- Maximum speed: 132 mph (212 km/h, 115 kn)
- Cruise speed: 107 mph (172 km/h, 93 kn) at 1,700 rpm
- Stall speed: 57 mph (92 km/h, 50 kn)
- Range: 570 mi (920 km, 500 nmi)
- Service ceiling: 16,500 ft (5,000 m)
- Absolute ceiling: 18,600 ft (5,669 m)
- Absolute ceiling on 2 engines: 7,100 ft (2,164 m)
- Rate of climb: 920 ft/min (4.7 m/s)
- Time to altitude: 7,200 ft (2,195 m) in 10 minutes
Congratulations are in order to India’s space agency, the Indian Space Research Organization (ISRO), on their successful moon landing with Chandrayaan-3. This is a great achievement for any organization and India well deserves their feeling of pride in the accomplishment.
A soft touchdown on the moon is a challenging task every time it is done and requires that a great many systems in a lengthy sequence of events perform perfectly. Presently, the rover has deployed properly and is in motion.
The Chandrayaan-3 spacecraft is comprised of a propulsion module, a lander and a rover. Each is equipped with scientific instrumentation.
Lander
- Chandra’s Surface Thermophysical Experiment (ChaSTE) will measure the thermal conductivity and temperature of the lunar surface.
- Instrument for Lunar Seismic Activity (ILSA) will measure the seismicity around the landing site.
- Langmuir Probe (LP) will estimate the near-surface plasma density over time.
Rover
- Alpha Particle X-Ray Spectrometer (APXS) will derive the chemical composition and infer the mineralogical composition of the lunar surface.
- Laser-Induced Breakdown Spectroscope (LIBS) will determine the elemental composition (Mg, Al, Si, K, Ca, Ti, Fe) of lunar soil and rocks around the lunar landing site.
Propulsion module
- Spectro-polarimetry of Habitable Planet Earth (SHAPE) will study spectral and polarimetric measurements of Earth from the lunar orbit in the near-infrared (NIR) wavelength range (1–1.7 μm [3.9×10−5–6.7×10−5 in]).
Russia’s Roscosmos Space Agency suffered a setback in its moon landing ambitions with the loss of its Luna-25 lander. Launched August 10 from the Vostochny Cosmodrome in southeastern Russia, contact with the craft was lost after a command was sent for it to lower its orbit around the moon. By August 20 Roscosmos had to conclude that the vehicle had impacted the moon. This was the first Russian attempt to land a probe on the moon since Luna-24 in 1976. The goal was to land at the 100-kilometre-wide Boguslawsky crater.
Source: NASA/GSFC/Arizona State University.
The science payload aboard Luna-25 was substantial-
- ADRON-LR, active neutron and gamma-ray analysis of regolith
- ARIES-L, measurement of plasma in the exosphere
- LASMA-LR, laser mass-spectrometer
- LIS-TV-RPM, infrared spectrometry of minerals and imaging
- PmL, measurement of dust and micro-meteorites
- THERMO-L, measurement of the thermal properties of regolith
- STS-L, panoramic and local imaging
- Laser retroreflector, Moon libration and ranging experiments
Some vocabulary from bad old days of the Cold War has come back to haunt us. Russia has announced that it has deployed its RS-28 Sarmat intercontinental ballistic missile (ICBM) in Belarus. The 112 ft long, 211 ton missile is said to carry 15 Multiple Independent Reentry Vehicles (MIRVs). As new and scary as this sounds, the US first conceived of the MIRV in the early 1960’s and deployed its first MIRV’d ICBM (Minuteman III) in 1970 and the first MIRV’d SLBM (Poseiden Sea Launched Ballistic Missile) in 1971. The USSR followed suit in 1975 and 1978, respectively.
In the early 1960’s it was believed in the US that it was behind the USSR in what was called the “Missile Gap”. It turns out this was incorrect and that, in fact, the US had a large advantage in the number of ICBM strategic delivery vehicles. For a long while we in NATO thought the Soviets were 10 feet tall and that turned out to be an exaggeration. From their performance in conventional battle, they have diminished in stature just a bit. However, their nuclear triad is to be respected.
The initial purpose of the MIRV concept was to compensate for inaccurate delivery. It has evolved to include decoys and multiple target delivery. There is a good deal of non-classified information on MIRV systems on the interwebs.
Putin’s threat of a new MIRV’d missile is just more nuclear bluster to frighten NATO citizens. For the present time his nuclear weapons are more valuable in storage as they have been all along with the Mutual Assured Destruction policy. That said, they have a policy of using nukes if the security of the state itself is under threat. I would guess that Putin sees himself as the state.
I wonder if it has dawned on the Russians that nobody in their right mind would actually make a preemptive attack on Russia or its former Soviet satellites. Who actually wants the place? What benefit is there in trying to subdue 140 million angry Russians and their huge frozen taiga? That’s nuts.
A paper is out comparing the resources needed to send women vs men on a trip to Mars. The paper, appearing in Nature publication Scientific Reports is: Scott, J.P.R., Green, D.A., Weerts, G. et al. Effects of body size and countermeasure exercise on estimates of life support resources during all-female crewed exploration missions. Sci Rep 13, 5950 (2023). https://doi.org/10.1038/s41598-023-31713-6.
The paper is worth a look, but I’ve cut and pasted the conclusions below-
When compared at the 50th percentile for stature for US females and males, these differences increased to − 11% to − 41% and translated to larger reductions in TEE, O2 and water requirements, and less CO2 and Hprod during 1080-day missions using CM exercise. Differences between female and male theoretical astronauts result from lower resting and exercising O2 requirements (based on available astronaut data) of female astronauts, who are lighter than male astronauts at equivalent statures and have lower relative VO2max values. These data, combined with the current move towards smaller diameter space habitat modules, point to a number of potential advantages of all-female crews during future human space exploration missions.
A female crew would require less energy and less weight in provisions than men just from the benefits of smaller scale metabolism alone. Looks like hurtling women to Mars is an all-around winning idea.
Recently, the FAA had a fiasco with its NOTAM service. Departures were halted system-wide and there was general fear and loathing in the air transport industry. According to Flying magazine, in a preliminary statement the FAA is claiming the cause of the shutdown was related to a damaged database file. The purpose of the NOTAM is to provide important and current information to pilots. There have been facile comparisons to the previous fiasco with Southwest Airlines. Easy does it there folks.
NOTAM used to stand for Notice To Airmen. It was changed to Notice To Air Missions. I guess this is now gender neutral.
Meg Godlewski at Flying magazine writes-
NOTAMs provide essential information to pilots about the abnormal status of a component of the national airspace system, such as ground-based navigational system failures at airports, GPS outages, and facility closures. Pilots are required to check for NOTAMs pertinent to for their departure airport, route, and destination as part of preflight planning.
The content of a NOTAM is written in a highly abbreviated manner. This continues from the days of the teletype machine where brevity was important due to the limitations of communication technology. An example of a NOTAM from an FAA website is shown below-
e. Changes to usable runway length and declared distances
EXAMPLES-
…RWY 19 THR DISPLACED 300FT MARKING NOT STD. DECLARED DIST: TORA 6827FT TODA 6827FT ASDA 6827FT LDA 6527FT. ….
…RWY 01 DECLARED DIST: TORA 6827FT TODA 6827FT ASDA 6527FT LDA 6527FT. …
NOTE-
Runway 19 threshold is displaced 300 feet, therefore the Runway 19 landing LDA is shortened by 300 feet. The LDA and ASDA for Runway 1 are also shortened by 300 feet.
EXAMPLE-
…RWY 05/23 NE 500FT CLSD. DECLARED DIST: RWY 05 TORA 7002FT TODA 7002FT ASDA 7002FT LDA 7002FT. RWY 23 TORA 7002FT TODA 7002FT ASDA 7002FT LDA 7002FT. …
NOTE-
Construction on Runway 05 requires 500 feet to be closed to protect a construction area thus changing declared distances to Runways 05 and 23.
EXAMPLE-
…RWY 08/26 CHANGED TO 10000FT X 150FT. DECLARED DIST: RWY 08 TORA 9000FT TODA 9500FT ADSA 9000FT LDA 9000FT. RWY 26 TORA 9000FT TODA 9000FT ASDA 9400FT LDA 10000FT….
Notice that each example has a “translation” in plain English. It seems like there is no longer a technology-related need for this kind of abbreviated and cryptic text.
In government there is a general hesitancy to fund upgrades to infrastructure, unless maybe it relates to defense. An upgrade of the NOTAM system isn’t like executing a moon landing or splitting the atom. It is plainly needed IT work and when the congress gets through parading their indignity in front of the cameras, they should be able to get started on funding and mandating a fix in the system.
History. I’m preparing myself for the upcoming May 27th release of Top Gun: Maverick. To be blunt, I’m still disappointed by the first movie which was released in 1986, so I’m bracing to be disappointed again. Make no mistake, I am an aviation enthusiast and I did really enjoy the flying action scenes with the F-14’s in the first movie. The flying shots were well thought out and captured on film. So, what’s not to like? Well … the rest of the story. The content that is left over when you take out the aircraft and the flying. Roger Ebert of the Chicago Sun-Times said it best, “”Movies like Top Gun are hard to review because the good parts are so good and the bad parts are so relentless.”
Current. On to the recent release, Top Gun: Maverick. As before the flying sequences were quite good. But again it was against the backdrop of, well, a dumb story. As before the story is written to feature studly macho bravado against the lone-wolf instinct on the part of Maverick. The strenuously independent behavior of Maverick flies in the face of military discipline and is where I part company with the story.
The old timer, Maverick, is finally brought in to lead a group of Top Gun fighter jocks to bomb a highly defended hard target in what looks like a deep crater with impossibly steep walls. Among the best of the best, Maverick is regarded by old timers to be the very best despite his undisciplined ways. Of course, the new generation of fighter pilots are skeptical.
A lot happens … yada, yada, … love interest … yada, yada … guilt trip …. etc, etc … steal a fighter from the enemy … resolve to overcome adversity one more time … zip, zing, zowie … triumph!!
A movie is entertainment that requires you to set aside disbelief. Very often I can do it. But this time I couldn’t.
The electronic media have dumbed down the weather map so much that it is difficult to find a decent weather map that shows high and low pressure centers, isobars, and frontal boundaries. Fortunately, the NOAA National Weather Service publishes up-to-date aviation weather maps for public use. Have at it.
Lamentations on Chemistry 
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