Tuesday, November 17, 2015

Why Air Is Hot When You Fly Fast

This article is for readers who are not trained in high speed compressible aerothermodynamics,  but who wish to understand why air friction and capture processes make air so very hot when you fly very fast through it.  The article explains why there is no such thing as cooling air,  once you have busted Mach to any significant amount.  

Captured Air (Scooped-Up by Any Sort of Inlet,  Including Cooling Air Inlets)

In order to do anything with atmospheric air inside a flight vehicle,  you have to scoop it up,  and decelerate it relative to yourself.  The air has a certain internal energy associated with its temperature,  plus some pressure energy associated with its ambient pressure.  Lumped together,  these are the air’s “enthalpy”,  the energy of its existence at those conditions. 

From your point of view inside the vehicle,  the air,  which has that certain enthalpy,  is also moving toward you very fast,  which is a kinetic energy.  Looked at from the air’s point of view,  it has to pick up an enormous speed in order to come aboard your vehicle.  Either way,  it is the same increment of kinetic energy. 

You add the kinetic energy change to the original enthalpy,  and that is the new enthalpy of the captured air at rest aboard your vehicle.  This enthalpy translates directly into a temperature measurement at the pressure conditions aboard your vehicle,  which are quite often different that in the ambient atmosphere.  What happens here is conservation of energy.  

Because of these changes in pressure,  it is more convenient to figure things directly from enthalpy,  symbolized as h in most textbooks on thermodynamics:

                h = m Cp T  (defined this simply only for absolute temperature)

where m is the mass,  Cp is the specific heat at constant pressure,  and T is the static (thermodynamic) temperature.  The energy that is conserved is the enthalpy h:

                h(ambient) + KE = h(on board)

where KE is the kinetic energy of the air 0.5 m V2,  and V is the absolute velocity of the vehicle.  If the velocity of the air once it is on-board is zero relative to the vehicle,  then its calculated temperature is maximum,  which we call the “total” or “stagnation” temperature.

If the air is still in motion aboard the vehicle at some velocity v,  then it still has some kinetic energy as measured on-board:

                KE(on board) = 0.5 m v2

Which must be subtracted from the on-board h in order to calculate the actual thermodynamic (“static”) air temperature.  That is why static temperature is always less than total temperature:  some of the energy that could have been enthalpy is still kinetic energy instead. 

Hot Boundary Layer Adjacent to Vehicle Skin

This phenomenon works by dissipation (waste) of energy,  instead of conservation of energy.  It is only readily apparent once vehicle flight speeds exceed transonic.  It has increasing effect very rapidly as supersonic speeds increase.  The effect is quite dominant in the hypersonic speed range. 

Understanding this effect requires the same “book-keeping” of static versus total temperature as before,  plus another calculated temperature called the “recovery temperature”.  This is an empirical concept that correlates how viscous dissipation converts KE to waste heat in the intense fluid shear zone that is a boundary layer adjacent to a flight vehicle’s lateral skin.  Yet the recovery temperature is an item that actually does physically exist,  and can be measured within that boundary layer. 

The difference between static temperature T and total temperature Tt is a measure of the air’s kinetic energy,  as already discussed above.  This increment represents the maximum possible energy that could be dissipated by viscous friction in the boundary layer.  Not all of it is wasted (although most of it is),  which is why recovery temperatures fall between static and total temperatures.

How much energy gets dissipated,  showing up as recovery temperature,  depends upon whether flow is laminar or turbulent.  For vehicles of ordinary size,  such flow is nearly always turbulent,  for reasons beyond scope here.

The correlation depends upon a property of the air called Prandtl number,  which for air is in the vicinity of 0.7.  The recovery factor applied to the total-minus-static temperature difference in the correlation for turbulent flow is the cube root of the Prandtl number (square root if laminar).  

Recovery temperatures Tr are the adjusted difference added to the static value.  These are very close to total temperatures,  the recovery factor being about 89% in turbulent flow.

The high-velocity dissipative boundary layer concept is shown in Figure 1What drives heat transfer to or from the skin is not the difference between skin and ambient temperatures,  but the difference between the skin and the (much higher) recovery temperature. 

I have plotted in Figures 2, 3, and 4 recovery (Tr) and total (Tt) temperatures vs flight Mach number at 3 different altitudes for a particular model of the atmosphere.  The ambient air static temperature T is different at each altitude.  Figure 5 shows how T varies with altitude in that model atmosphere (the US 1962 Standard Day model,  extended to the edge of space).  

The higher the ambient static temperature,  the higher the trend of Tr and Tt,  compared at the same flight Mach number.  Yet it is flight Mach number that dominates,  regardless.  If you are scooping cooling air,  and that air must be below boiling water temperatures to do its job,  then there is no such thing as cooling air for you at speeds between Mach 1.2 and 2,  regardless of which figure you examine.  Because the ambient static temperatures are the same,  the 110,000 ft data in Figure 4 looks just like data for 28,000 feet.  

If you look at the Tr or Tt data in the vicinity of Mach 6 in any of these figures,  you see temperatures in the vicinity of 3000 deg F.  For reference,  the meltpoint of iron and steel is 2935 F.  That,  more than anything else,  is why hypersonic flight is so very difficult.  

I apologize to readers who prefer metric units,  because these plots are not in metric units.  Here is the conversion information for you:

Deg F     the normal Fahrenheit non-metric temperature scale (corresponds to deg C in metric)
Deg R    the absolute Rankine non-metric temperature scale (corresponds to deg K in metric)
F and R use same size degree but different zero points,  0 R is absolute zero = -459.67 F

C and K use same size degree but different zero points,  0 K is absolute zero = -273.15 C
Deg K = deg R/1.8
Deg C = (deg F - 32)/1.8

Figure 1 -- Boundary Layer in High-Speed Flow

Figure 2 -- Temperatures vs Mach at Sea Level
Figure 3 -- Temperatures vs Mach in the Stratosphere

Figure 4 -- Temperatures vs Mach at Very High Flight Altitude

Figure 5 -- Temperatures vs Altitude in the Standard Day Model

Wednesday, October 7, 2015

Oregon Mass Shooting and Gun Control

Update 11-16-2015:  I have seen nothing to change any of these opinions or conclusions.

Original Posting:

Yet another mass shooting (this one at a community college on Oregon) prompts yet again calls for stricter gun control laws.  That’s the “usual response”,  and it is wrong.  Here’s why….

If stricter gun control laws were actually successful at reducing violence,  then Chicago and Washington DC would be the safest cities in America in which to live,  precisely because they have the strictest gun control laws.  They are actually the most violent cities in America by the statistics,  and by far. 

So,  clearly,  this approach is wrong,  it does not work.  QED.  Get over it! 

Look a bit deeper than the customary knee-jerk reaction,  for something that might actually work,  and try that instead!  To keep trying something again and again,  that does not bring about what you want,  is a pretty good operational definition of insanity.  Just how insane are you,  my neighbors?

This means that you look for what might actually be causing the problem,  and do something about that,  instead.  You will not find it by listening to knee jerk reactions and political sound bites. 

You might try history instead,  but you’ll have to be read between the lines to find any truth in history.  It’s written only by the winners/survivors. 

If you look at mass shooting incidents over the last several years,  there are really only two common threads.  And that’s a good place to start.  (1) With one exception,  every one of these incidents is an example of people known to have mental problems getting guns legally.  (2) Without exception,  every single one of these was a gun-free zone that was not adequately defended. 

The exception to (1) was the Newtown school incident,  where the perpetrator obtained his guns illegally.  He killed his mother,  so he could get access to her guns,  otherwise locked up beyond his reach.  That right there ought to tell you something! 

Current laws are based on a federal standard that is essentially an “on-off switch” with too high a bar.  To be prevented from obtaining guns,  a crazy person must be judged crazy by a judge in a court of law.  Otherwise,  he may buy the gun legally,  and the seller has no grounds not to sell it to him.  Period. 

That’s demonstrably the wrong standard.  It was written that way to make things easy and convenient for lawyers and judges.  Yet it quite demonstrably kills people.  The people who sold “xxx” the gun with which he shot congresswoman Gabby Giffords were uncomfortable selling him a gun,  but they had no choice.  That is a matter of public record. 

It is simply outside my expertise to give you practical details,  but I do suggest a staged,  multi-step approach to this.  If a seller is uncomfortable,  that should spark a deeper investigation by local law enforcement than just a review of existing paperwork on file.  Family,  friends,  and colleagues should be questioned about just how well we can trust “xxx” to behave responsibly with his weapons. 

As for item (2) defense of a gun free zone,  we have the example of the 19th century American frontier.  There are perfectly-good reasons to establish gun-free zones,  well-known since long before that time.  It actually works quite well to reduce violence,  if done correctly.  Not done correctly,  this approach demonstrably does not work.

There are two items,  completely forgotten today,  that are required to do a gun-free zone correctly.  (1) An easy way to comply by checking your weapons with local law enforcement when you enter the gun-free zone,  with easy retrieval when you leave.  (2) Timely defense of the gun-free zone (extremely crucial).  Of the two,  (2) is more important,  but both are actually crucial to success.  

The history of the 19th century American frontier confirms this assessment,  if and only if you look very closely at it. 

Today,  we completely ignore item (1),  and force people who are armed to leave their guns at home,  or (more damaging to us all),  in their cars.  Guns left in cars are targets for criminals who steal them and use them to commit violent crimes.  Period.  End of issue.  Not to mention terrorists. 

We have known this since the 19th century.  That’s why back then,  you checked your guns with the local sheriff/town marshal/constable (pick a name) when you entered town.  You knew they would be safe in his custody.  And you knew you could drop by his office and pick them up easily when you left town.  This stopped a huge proportion of the drunken-cowboy gunfights in saloons. 

Item (2) is more arguable today.  Back then,  a town was a physically-small thing around 2,  or at most 3,  modern city blocks in dimension.  An armed deputy could arrive anywhere in town within about 60 seconds,  at a dog trot. 

This standard of response time actually worked quite well.  It did not prevent every problem,   but it did prevent the vast majority of them.  That’s the real truth of our history. 

There’s absolutely nothing in any of the accounts to suggest that anything is any different today.  In point of fact,  the longer the response time,  the worse the typical outcome.  5 minutes is too long.  20+ minutes is way too long.  Period.

Now,  the mistake made at every mass shooting site in the last several years is not defending the gun-free zone adequately (essentially a 60-second response).    

In Oregon,  they not only declined to have an armed officer on site,  they declined to have an unarmed officer on site (all this is a matter of public record).  Just how stupid is that?

So,  what do you defend your gun-free zone with?  I suggest that only folks with actual peace officer training qualify.  You are quite literally counting on whoever might be armed to do a peace officer’s job. 

The holder of a concealed-carry permit might be trained in what he can and cannot do with his firearm,  but HE HAS NOT BEEN TRAINED TO BE A PEACE OFFICERThere’s quite a difference. 

What that says is that Donald Trump is wrong when he says the faculty should have been armed at the community college in Oregon.  It takes a real peace officer to defend a gun-free zone,  just like it did in the 19th century American  frontier.  

Saturday, September 12, 2015

Go Look It Up for Yourself

I get very angry with the widespread and flagrant abuse of the words “liberal” and “conservative” for over-hyped political activity.  What angers me most is how these words are used by each side to defame the other,  with all sorts of political agenda items incorrectly implied to be part of their definitions.

I suggest that you go look up the definitions for yourselves,  but I already know that the most flagrant abusers will not do that.  So,  here are the definitions from my old “Random House Dictionary of the English Language,  College Edition”,  published in 1968 by Random House,  New York,  and based upon their larger volume “Random House Dictionary of the English Language,  Unabridged Edition”,  from 1966 and 1967.  (Nothing about these words has truly changed since then.) 

(Page 286) conservative:  adj 1. disposed to preserve existing conditions,  institutions,  etc.,  and to resist change.  2. cautious,  moderate:  “a conservative estimate”.  3. traditional in style or manner;  avoiding showiness:  “a suit of conservative cut”.  4. (cap.) of or pertaining to the Conservative party.  5. of or pertaining to political conservatism.  6.  having the power or tendency to conserve; preservative.  7. of or pertaining to Conservative Judaism or Conservative Jews.  n.  8. a person who is conservative in principles,  actions,  habits,  etc.  9.  a member of a conservative political party.  10.  a preservative.

Definitions 1,  2,  5,  8,  and 9 pertain to American politics.  Accordingly,  here is a related definition:

(Page 286) conservatism: n.  1. the disposition to preserve what is established and to resist change.  2.  the principles and practices of political conservatives.

The sense of all that for American politics,  expressed colloquially,  is that a political conservative is dominated by the idea that “if it ain’t broke,  don’t fix it”.  There is nothing wrong with that.  But it isn’t a complete philosophy,  because not all traditions do for us what we want. 

(Page 772) liberal:  adj 1. favorable to progress or reform,  as in religious or political affairs.  2. (often cap.) noting or pertaining to a political party advocating measures of progressive political reform.  3.  of or pertaining to representational forms of government rather than aristocracies or monarchies.  4.  of,  or pertaining to,  based on,  or advocating liberalism.  5. favorable to or in accord with concepts of maximum individual freedom possible,  especially as guaranteed by law and secured by governmental protection of civil liberties.  6. favoring or permitting freedom of action,  especially with respect to matters of personal belief or expression.  7.  free from prejudice or bigotry,  tolerant.  8.  open-minded or tolerant,  especially free of or not bound by traditional or conventional ideas,  values,  etc.  9. characterized by generosity and willingness to give in large amounts.  10. given freely or abundantly.  11. not strict or rigorous;  free;  not literal.  12. of,  pertaining to,  or befitting a freeman.  n. 13. a person of liberal principles or views.  14. (often cap.) a member of a liberal party in politics,  especially of the Liberal Party in Great Britain.

Definitions 1,  2,  4,  13,  and 14 pertain to American politics.  Accordingly,  here is a related definition:

(Page 772) liberalism: n. 1. the quality or state of being liberal,  as in behavior,  attitude,  etc.  2. (sometimes cap.) the principles and practices of a liberal party in politics.  3. a political or social philosophy advocating the freedom of the individual,  and governmental guarantees of individual rights and civil liberties.  4.  a movement in modern Protestantism that emphasizes freedom from tradition and authority in matters of belief. 

The sense of all that for American politics,  expressed colloquially,  is that a political liberal is dominated by the idea that “if it is broke,  then do fix it”.  And there is nothing wrong with that.  But it isn’t a complete philosophy,  either,  because some traditions really do work well for us. 

I submit to you all that both ideas are absolutely essential to the good governance of our country,  at all levels.  All of us must be both liberal and conservative,  whichever need arises,  and whenever they show up. 

What you really have to decide is whether something is “broken”,  meaning dysfunctional,  not serving its intended purpose.  If it is,  the intelligent thing to do is to be a “liberal” and fix it.  If it is not,  the intelligent thing to do is to be a “conservative” and leave it alone.  It’s really just that simple. 

The key advice I have to offer is to base your decision on whether something is “broke” on nothing but simple objective functionality.  That functionality evaluation should be a matter of demonstrable fact,  not anything political at all.  To do otherwise is a part of the madness that renders our governments so ineffective,  at all levels today.

The rest of that madness derives from dividing into two pigeon-hole categories (whose philosophies are dangerously incomplete at best),  and then each side misusing the words to tar the other.


Religious Freedom vs Sworn Duty?

Update 11-16-2015:  I have seen nothing since that would change any of these opinions or conclusions.

Original Posting:

Kim Davis,  a county clerk in Kentucky,  was recently sent to jail for contempt of court.  This was for refusing to issue marriage licenses to gay couples,  on account of her personal religious beliefs.  This refusal is in violation of a recent US Supreme Court decision making such licenses legal,  nationwide.

She has since been released.  But,  she is unrepentant,  and seems to have lots of supporters.

Videos posted on line do in fact show the nature of her interaction with that fraction of the public which actually is gay (under 10%).  She clearly refuses to issue the marriage license on account of her personal religious beliefs,  which in effect holds the requestor to the same religious practices as Ms. Davis

Yet issuing such licenses as this,  is the very nature of the job she holds.  It is county clerks who typically issue marriage licenses.  They are sworn to uphold the law regarding this function,  and many others. 

Nearly all of us have heard the old saw about how individual rights are not absolute:  your right to swing your fist ends before your fist reaches my nose.  We can always debate exactly where your right to swing your fist actually ends,  but the basic principle is always somewhere before you strike my nose,  no exceptions. 

Similarly,  all of you have a right to believe in any sort of religious traditions that you choose,  and to practice them in any way that suits you.  But,  that right of yours is not absolute.  Your right to practice your religion ends somewhere before you impose your personal beliefs and practices upon me.  Or anybody else.  Just like your right to swing your fist ends before you strike anybody. 

We do not all believe in exactly the same religious teachings.  That is precisely why we established a fundamental principle of separation of church and state,  for one thing. 

For another,  our common law must be the lowest common denominator we all can agree upon,  else the union will inevitably dissolve in some sort of insurrection.  We’ve seen this effect before – it led to the Civil War,  for one thing. 

To do otherwise than lowest common denominator for common law is thus demonstrably insane policy.  That common-denominator approach comes from the same limitations-on-rights principle as exists for fist-swinging.    In point of fact,  it underlies most of the truly fundamental American legal traditions. 

Ms. Davis is faced with a personal moral dilemma:  either she is true to her sworn oath to uphold the law,  or else she is true to her personal religious beliefs.  If she cannot find it within herself to issue marriage licenses to gay couples,  then she should not continue in her job as county clerk.  Simple as that. 

I would suggest that her county look for another position she could fill,  outside of this moral conflict,  before they either fire her,  or accept her resignation.  That is because her job expectations changed after she assumed the position,  thanks to the Supreme Court decision.  Fair is only fair. 

But,  I see no other practical options available to her,  or to her county. 

That being said,  this same limitations-on-rights principle has other applications in American life.  One obvious one has to do with the politics of abortion. 

Science says there is no distinct line between human life and not-life.  It is a gradual spectrum,  pure and simple.  Any line we draw is both purely human and entirely arbitrary.  Saying otherwise does not refute this truth. 

If you base your decision on the potential ability of cells to reproduce,  then you should never even contemplate clipping your fingernails.  That is patently ridiculous,  even to the most religiously-fundamentalist among us. 

Equally insane would be to base it on actual birth.  That’s because we have evidence of self-awareness in fetuses nearing full-term.  So where do you draw the line?  Everybody has a different suggestion,  but all lie between the two endpoints of conception and birth. 

But when you combine that inherent human uncertainty with the fact that not all of us share the same religious beliefs and practices,  you inevitably conclude that the “line” between human life and not-life is entirely an arbitrary matter.  There is no line,  except what we together choose to draw. 

Once you realize that any such line is arbitrary,  then inevitably it follows that we need to draw that line as the lowest common denominator that we all can agree upon.  We collectively,  who separately have such disparate beliefs,  must be able to live within any such law.  In other words,  the limitation-on-rights principle applies,  including any religious teachings we may bring to bear on the decision.

Why is this limitations-on-rights principle so important?  Why is separation of church and state so important?  These traditions are almost unique to America.  But,  these (and our other unique rule-of-law traditions) are the sources of much of our individual freedom.  That’s what makes them so important. 

Look at other countries that lack such traditions,  and you can readily see how easily one group dominates the others,  misusing religion to justify this,  and to justify virtually any atrocity to enforce it.  Africa and the Middle East are just eaten-up with that evil. 

We surely don’t want that here! Open that door for one,  you have opened it for all.  

Iran Nuclear Deal Nonsense

Update 11-16-2015:  I have seen nothing since that would change any of these opinions,  conclusions,  or recommendations.

Original Posting:

I am so sick of all the political crap being spewed about the Iran nuclear deal that I could just throw up! 

The pros (mostly Democrats) talk about verification,  but not about what they would do if Iran cheats (and they will – see below).  The cons (mostly Republicans) cry excessively loudly about “how bad this deal is”,  but they have absolutely nothing credible to offer as an alternative (same as all the other things they want to reverse). 

I’m sick and tired of the whole lot of them.  But that’s a topic for another time.

The Iranians will cheat,  in fact there’s some hints floating around on the internet that their cheating attempts have already begun.  OK,  fine.  I have a plan for that. 

So,  there has to be a very dire consequence for cheating,  or else misbehavior and lying will continue unabated.  That’s been Iranian history ever since the old Shah was overthrown,  and even he was very far from truthful (I am an old guy,  I remember that). 

Don’t be misled,  Iran is not alone in this deceitfulness!  There are no Middle Eastern countries that value truth at all!  There never have been,  not since Hammurabi,  or the tales in the Old Testament (that Christians,  Jews,  and Muslims all share) would not read the way they do.  But that’s yet another topic for yet another time.

There is a solution to this problem that does not involve sending troops to the Middle East.  I don’t want to do that anymore,  no ordinary American does!  We’ve have quite enough of that BS in Afghanistan and Iraq,  thank you very much.  (I’m trying to be charitable here in how I express myself.)

But my solution does involve very extreme violence!  You must prepare yourself for that.  Nothing else is understood over there. 

If you do not make a grisly example of misbehavers,  then nobody over there will mend their ways.  They never have.  There’s over 5000 years of that very history recorded in the Old Testament,  verifying exactly what I contend.

What you do is start a countdown clock when the cheating reports start,  as regards the Iran nuclear deal.  You set the time interval fairly short,  somewhere between a week and a month;  there’s no point dragging this out. 

You tell them you started that countdown clock,  and if they do not correct their misbehavior (“here’s the written list”),  then you will nuke all of their nuclear facilities.  Period.  No argument.  No negotiation.  No leeway on the deadline. 

And then you carry out that threat,  on time.  You’ll have to,  as they will not believe it until you do it. 

Don’t tell them how you are going to do it!  But make this ultimatum quite public,  so all of Iran’s neighbors know in advance what is going to happen in that neighborhood.  “52 cards face up on the table”,  as it were. 

You do not want Russia,  for one,  to be surprised by what they see coming on the radar.  Because,  what I propose could risk World War 3,  if misinterpreted by any nuclear power in the region.  Leave zero room for misinterpretation on anybody’s part! 

Do NOT send warplanes.  Do NOT send bombers.  ABOVE ALLdo not send ships and troops.  Give them zero warning of what you are doing.  Hit their nuclear sites with nuke-tipped ICBM’s,  in at least 2 waves.  It’ll all be over,  in about 1 hour.

These sites we target are well outside Tehran and the other cities.  Civilian casualties will actually be very low,  if any at all.  But the message about “what could happen next” will NOT be lost on those ruling mullahs,  no matter how thick-headed they really are (and they really are !!!). 

This could be the beginning of the end for them,  as their people catch on to what just happened.  And that would be a good thing!  And not just for us,  as Iran and Saudi Arabia are the two biggest funders of organized terrorism in the world today. 

We do this,  and all the other Middle Eastern countries will fall into line for a while,  and behave themselves.  But only for a while.   You will have to do it again to a different one,  somewhere down the road.

Then,  all you need do is figure out how to destroy the evil extremists like ISIS.  But,  if you have actually nuked a bad actor like Iran,  then even they (ISIS) might start to behave a little better.    All it takes is an extreme punishment example.

Friday, August 7, 2015

Access to Space: Commercial vs Government Rockets

A recent newspaper column by Michael Griffin and Daniel Dumbacher claims the new SLS launch vehicle is essential to the nation’s space program.  The column also claims that SLS costs are expected to be about the same as current commercial launchers.  Griffin is a former NASA administrator,  and Dumbacher is a former deputy associate administrator. 

NASA has its critics,  and it has a demonstrated history of badly underestimating costs,  which is primarily why it has critics.  I am not interested in criticizing anyone.  Personally,  I am just interested in the best facts and estimates that I can uncover.   The SLS will certainly have its critical uses.  I am less confident than Griffin and Dumbacher in its cost-effectiveness. 

Back in 2012,  I searched out payload data and launch cost estimates for several launch vehicles,  some domestic,  and some foreign.  There was some conflicting information,  which I resolved as best I could.  Where possible I used data direct from the manufacturers.  Some of the vehicles I researched are no longer flying,  some have not flown yet,  but most are flying today. 

To this database I have added this year the historical data for the NASA space shuttle (now retired),  and the best available projections from NASA (and from NASA’s critics) for its new SLS vehicle,  currently under development.  There is considerable disagreement and uncertainty about the projected launch prices for SLS in its 3 projected versions.   Much depends upon the actual flight rate,  which was presumed to be once a year for the data I used.  See figure 1 for my database.

 Figure 1 – Database on Payloads and Costs,  Including Sources of Data

This kind of data comes from sources across a multitude of years,  which requires correction for inflation to a common comparison year.  My original database is corrected to 2012 dollars,  and I did not change that.  The SLS estimates have not really changed by any amount I could find from 2012 to present.  Inflation rates have been quite low for many years.  I used 2% as a representative figure.  See figure 2 for my inflation-adjusted launch prices.

 Figure 2 – How Launch Costs Were Adjusted for Inflation to 2012 Dollars

What I generated with this data was a plot of unit prices to low earth orbit (LEO) as a function of payload mass sent to LEO.  You calculate this as launch price divided by the max payload capability (in this case to LEO).  Then you plot that unit price versus max payload.  It is generally expected that there should be a gently-decreasing trend of unit price as payload size increases,  especially for vehicles that compete commercially in the satellite launch business.  This is the “price break for larger sizes” effect,  in rockets. 

This unit price (expressed here as millions of 2012 dollars per metric ton of payload) represents a minimum unit cost to send payload LEO,  obtained only because the rocket flies “full”.  You must remember that the rocket costs the same to launch whether it flies “full” or not.  If the rockets fly “half full”,  then the achieved unit prices are twice those reported here.  10% full is 10 times the price,  etc. 

The units of measure here are 2012 dollars (in millions) and payloads measured in metric tons.  A metric ton is 2205 pounds per ton instead of the US customary 2000 pounds per ton,  so a metric ton is about 10% larger than a US ton.  But that’s still pretty close. 

I used two estimates for NASA’s SLS system:  their target is $500 million per launch at about one flight per year,  while their critics contend that figure is likely closer to $1000 million ($1 billion) per launch,  at that same flight rate.  Thus I show a lower-bound curve (NASA) and an upper-bound curve (their critics) for SLS.  See figure 3.  I used the same launch price for all three versions of SLS,  because the data are still too uncertain to resolve the price differences among the three configurations.  

Figure 3. – Unit Launch Price Comparisons to LEO

The expected trends of gentle price break with larger rockets is definitely there,  as illustrated by the commercial rockets.   That would be the Spacex Falcon family,  the ULA Atlas-V group,  Ariane,  Proton,  and ULA’s Delta-IV.  For the 20-ton class of payloads,  prices range from about 5 to about 8 million dollars per ton to LEO.  Extrapolating,  we would expect lower numbers at 50 and 100 tons,  based on these trends,  perhaps in the 1-3 million dollars per ton range. 

The Titan-IV data are considerably higher at around $23M/ton for a 20-ton-class payload,  but that is because Titan-IV was never used for commercial competitive satellite launch.  The others discussed so far were;  it’s not about the rocket as much as it is the logistics that support it.  That is how prices were reduced by a factor of 3 or 4,  for the same basic technology and the same payload class.  Titan-IV no longer flies,  it is obsolete and fairly-recently retired. 

The data point for the space shuttle represents an entirely-different technology:  the semi-reusable boosted space plane,  not a throwaway rocket booster.   Its deliverable payload in the cargo bay was 20 tons to LEO,  but what was sent to orbit was that plus a recoverable space plane,  totaling 100 tons.  For my curves,  I based the unit price on deliverable payload.  If instead you base that on the entire orbiting vehicle,  that unit price drops from $75M/ton to about $15M/ton,  very comparable to the non-commercial Titan-IV. 

However,  that’s still about factor 2-3 higher than what is currently available commercially in the same payload tonnage class.  In that sense,  the two government-only vehicles (shuttle and Titan-IV) illustrate quite clearly the effects of commercial competition upon simplifying logistics to lower the price per launch.  Commercial is about factor-3 cheaper for the same thrown payload than government. 

That government-vs-commercial effect shows up in the projected unit prices with NASA’s new SLS,  even if you accept their launch price estimates.  Over the 70 to 130 ton payload range,  that unit price ranges from about $7M/ton down to about $4M/ton. 

So far there are no commercial vehicles in that payload class,  but based on the commercial unit price trend,  one might reasonably expect such vehicles to price out closer to $1-3M/ton.  The SLS might actually turn out to be closer to $8-14M/ton (my upper-bound curve),  if NASA’s critics are closer to right.  In any event,  it is unlikely to fly before 2018 at the earliest,  based on what I read.  And it is very unlikely to be as cheap as any commercial rockets that may come to exist in that size class. 

Given those data that demonstrate a clear commercial cost advantage,  I would suggest for the near term using SLS only for those missions absolutely requiring 70-130 ton payloads.  Anything and everything else ought to “fly commercial” for around factor 3 savings.  And soon,  we won’t be restricted to 20-ton-class payloads on those commercial rockets.  Falcon-Heavy is supposed to fly its first time this year,  or next year,  providing a 53 ton capability. 

I don’t know about the other companies,  but Spacex is reportedly considering an upgrade to its not-yet-flying Falcon-Heavy that could up its payload capability closer to the low end of the range covered by the SLS configurations (about 70 tons). 

Spacex is also reportedly considering an entirely-new vehicle called “MCT” that equals or exceeds the payload capability of all the SLS configurations.  It will be very interesting to see how that one prices out,  as it will be designed by people with real competitive experience,  and with commercial competition in mind from the outset,  just like its earlier siblings. 

Meanwhile,  the political “long knives” have come out in Congress over the recent failures of a Spacex Falcon-9 and an Orbital Sciences Antares.  They seek to kill the new initiatives aimed at commercial crewed launch and commercial unmanned space station resupply. 

When you think about it,  all the rocket makers have had their histories of failures to overcome,  so it is clear the “long knives” are politically motivated to protect the older companies from the competition of the newer companies. 

Commercial is demonstrably cheaper than government-supplied,  and likely will always be cheaper.  It would be very unwise to listen to the “long knives”,  or to let them win.

Thursday, July 30, 2015

New Cactus Tool Website

If you need cactus removal from farm or ranch pastures,  please read on.  There is a new website for a mechanical method of how to kill cactus using a tool I developed.

Used properly,  it literally kills cactus (the prickly pear,  or some folks spell this prickley pear),  eradicating it permanently,  without pickup-and-disposal,  without chemicals,  and without disturbing the grass.  And your effort is reduced to driving your tractor around.  The end result is far better than any of the chemical or mechanical control methods that I have ever found.

This new site is something my son and I have been working on,  to greatly expand the cactus tool business I have operated for over a decade now.  Since I am retiring,  I can devote more time and effort to building and selling these very simple and effective tools.  Most people find it hard to believe how effective this approach is;  I could hardly believe it myself when I accidentally discovered how to do this.  But it is true:  this is really effective,  and without so much onerous work.

The new site is now operational as “http://www.killyourcactusnow.com”.  Here's a video from that site,  which tells you exactly how to kill cactus:

If that doesn't work for you,  try going directly to this site to see it:


It is a turnkey site designed specifically for online browsing,  information-gathering,  customization of your tool with options,  and secure purchasing.  Prices and options posted there supersede all others published elsewhere.  The information posted there will allow you to evaluate for yourself the relative economics of chemical sprays versus the purchase of a well-proven mechanical eradication tool. 

There are two basic cactus killer tool models:  the plain tool and the hydraulic tool.  Each comes with multiple options,  and each is equally durable.  The plain tool has no moving parts,  and is less expensive because it is simpler.  The hydraulic tool has hydraulically-operated transport wheels that enable it to “step over” the occasional bale of debris under the tool,  without manual clearing of that debris.  It is more complicated and expensive,  but is more capable of saving the owner time and effort.

The new site is jam-packed with text,  picture,  and video-clip information.  Go visit it and learn how to kill cactus,  permanently. 


Guide to all cactus tool articles on this site follows.  The yellow highlight indicates this article.


7-30-15......New Cactus Tool Website
...................turnkey site for info,  photos,  videos,  purchases
1-8-15……Kactus Kicker Development
………………production prototype & 1st production article
1-8-14……Kactus Kicker: Recent Progress
…………..….testing a revised wheeled design (experimental)
10-12-13..Construction of the Tool
………………building a “Kactus Kicker” (plain tool)
5-19-13…….Loading Steel Safely
……………….transport and storage of materials
12-19-12…Using the Cactus Tool or Tools
……………...how the tool is employed (applies to any model)
11-1-12….About the Kactus Kicker
..…………….painting and rigging finished tools (plain tool)
12-28-11..Latest Production Version
………………new bigger snout and barge front (plain tool)