Saturday, February 24, 2018

Yet Another School Shooting

A slightly-shortened version of this article appeared in the Waco Tribune-Herald newspaper as a guest column on Wednesday 21 February 2018.  I received one phone call from a reader I did not know,  indicating total agreement with what I wrote.  His only comment was calling a gun's ammunition magazine a "clip" is technically incorrect,  although most of the public does so.

Here is the full-length,  as-submitted form of the article:

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The latest school shooting incident in Parkland,  Florida,  exemplifies exactly the two “big-ticket” things demonstrated by the gun violence data,  if one actually goes and looks:  (1) we have a leak in the background check process that allows crazy people to get guns legally,  and (2) we are utterly failing to adequately defend our gun-free zones.  If you wish the lost kids' lives to have any lasting meaning,  then do something about those two problems!

Those same gun violence data (available in mass quantity from Motherjones.com) also show no significant protections are to be had from “the usual proposals”:  clip size limits,  “assault” rifle bans,  and such like. 

If you want to see exactly how to analyze such data,  visit http://exrocketman.blogspot.com,  click on year “2016”,  then click on month “June”,  then read the article titled “What the Gun Violence Data Really Say”,  dated June 21,  2016. 

I put quotes around “assault” rifle,  because things like the AR-15 are exactly like any semi-automatic hunting rifle in terms of firing rate.  The cosmetics have nothing to do with lethality. 

That being said,  it would be wise to ban bump stocks and trigger cranks,  those being devices that increase the firing rate of a semi-automatic weapon into the range of a fully-automatic weapon (machine gun).  The ban on civilian machine guns dates to the 1930’s,  with organized crime gangs using them in the streets.  That ban actually has been proven quite effective. 

Down to brass tacks:  Crazies Getting Guns

The current form of the ban on crazy people possessing guns is based on a court decision of insanity.  It’s a go/no-go “gate”:  if there is no court verdict of insanity,  there are no grounds to deny sale of the weapon. 

And that is exactly what was wrong with the Columbine incident,  the Gabby Giffords incident,  the Las Vegas incident,  many others,  and now the Parkland,  Florida incident.  Sandy Hook was different:  that shooter murdered his mother to steal her guns. 

In each case,  there were family,  friends,  and others aware of the mental problems of the shooters,  before their respective incidents.  In this last case (Parkland,  Florida),  many classmates and teachers knew this person was dangerous with a gun,  it appears the local law enforcement might have known “something” was wrong with him,  and the FBI was tipped off but failed to follow up. 

We need a multi-step decision process,  where anyone can voice a concern,  which leads to a real background investigation questioning real people who know or have interacted with the person in question,  not just an on-line records search.  That extra effort costs,  but the benefit is incidents prevented and lives saved. 

It all gets down to whether money trumps lives,  or vice versa.  Simple as that.  I recommend you judge your elected officials accordingly.

But,  the triggering of a deeper investigation must not presume “guilt”,  until and unless actual facts determine there really are mental problems.  We have to be very careful and very fair how we do this.  But it will help,  and very much more significantly than any of the usual gun control proposals. 

Down to Brass Tacks:  Adequately Defend the Gun-Free Zones

This is something we are currently not doing at all.  Accordingly,  the people in these gun-free zones are perceived to be sitting duck targets by both the crazies-with-guns and the terrorists.  And they are sitting-duck targets. 

Don’t get me wrong:  there are perfectly good reasons to have gun-free zones.  Schools,  shopping centers,  and churches are but a few of many such venues.  Everybody understands why this is so.

But,  we learned in the 19th century frontier towns that you have to defend your gun-free zone adequately.  That means a properly qualified guard or guards,  and a response time under 1 minute. 

Properly-qualified means peace officer training,  not just concealed-carry training.  This is because any armed guard will be called upon to respond as a peace officer if there really is trouble to quell.

The 1-minute response is based on the fact that those same 19th century frontier towns were small.  A deputy from the sheriff’s office could be anywhere in town in under a minute at a dog-trot,  at the first sign of trouble.  When towns got bigger (more than a minute to respond),  death tolls went up.  Simple as that. 

So,  defend the gun-free zones,  and the crazies and terrorists will no longer attack those venues,  by and large.  This will reduce deaths quite significantly,  unlike the “usual proposals”.


Again,  does the money trump the lives,  or vice versa?  That’s how you have to judge those charged with making these decisions.

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Follow-up comments for this posting:

In the days following the shooting in Parkland,  it has been revealed that a deputy did not go inside and take on the shooter immediately.  Why has not yet been revealed.

But,  one possible reason is being outgunned by the shooter.  Most deputies have a revolver as a sidearm,  something little different from an Old West six-shooter.  Compared to a semi-automatic rifle,  that kind of weapon has less stopping power,  less rate of fire,  a less effective range,  and a much smaller quantity of shots,  before a much slower reload process is required.  A deputy with nothing but a revolver is way-outgunned.  

Such a deputy is properly qualified as a peace officer,  but is not properly equipped to do his job taking on a heavily-armed shooter.  So,  in addition to what I said above about who is qualified to defend a gun-free zone,  such a guard must also be properly equipped.

In this article,  I also didn't take on mental health care in this country.  There is something about modern American life that seems to be both causing mental issues,  and provoking sufferers to act out.  That issue needs to be fixed.  Again,  hold your politicians accountable.

Arming teachers to be the guards is a bad idea because:  (1) it destroys the atmosphere of trust in the classroom,  (2) the teachers have way more than enough to do already without being called upon to act as guards,  (3) no teacher armed with a handgun is adequate against a shooter armed with long guns,  and (4) nobody will pay them to take on the added risk and workload (they are already not paid enough even just to be teachers).  That idea is just insane.  Whether it comes from Wayne LaPierre or Donald Trump,  it is still insane.

One other point:  there is no difference between an AR-15 and a semi-automatic hunting rifle in terms of lethality.  Neither weapon is a proper "assault weapon" in today's military environment,  because neither is a machine gun.  Period.  End of issue.

Those calling AR-15's "assault weapons" display their ignorance for all to see.  Semi-automatic weapons were actually obsolete before Vietnam,  and proved in combat to be a real loser of an idea for battle in Vietnam.  (That does not address the comparison of the fully-automatic machine gun form M-16 versus the machine gun AK-47,  or the decades it took to correct the reliability problems experienced with the M-16 that the AK-47 did not suffer.)

But,  there is the issue of law enforcement being able to visually determine what they are up againstNo one adds a bump stock or a trigger crank to a hunting rifle.  Protecting our law enforcement people from semi-automatic weapons modified to be effective machine guns (as in Las Vegas) might actually be a good reason not to sell AR-15's and similar to the public.  That idea does deserve some thought and discussion,  even though we already know in general that most prohibitions don't work. 

In conclusion:  "something" needs to be done,  that's for sure.  My take on it is:  why not try those things that might actually confer significant benefit,  instead of the same,  lame old "knee-jerk" things that we already know won't help?

Find a way to stop selling guns legally to crazy people.

Defend the gun-free zones properly.

Friday, February 9, 2018

Launch Costs Comparison 2018

This article compares and correlates unit costs for launchers,  mostly those used commercially.  These data are based upon reported payload capacities and launch costs found in the literature.  The format is cost per unit delivered payload mass,  on the very important assumption that the launcher flies fully loaded.  All figures are at the end of this article.  Click on any figure to see any or all of them enlarged.  You can close that view box and be right back to viewing this article.  

Results are reported in millions of dollars per delivered metric ton,  and in dollars per delivered pound.  To estimate the unit cost when flying at less than full load,  simply divide these unit costs by the fraction of fully-loaded that you intend to fly. 

Scope includes the launchers used in the competitive satellite launch business,  plus a few launchers that were used,  but not competitively,  and the US Space Shuttle as representative of a large spaceplane.  Some of these launchers are no longer in service.  However,  the correlation results are used to predict unit costs for the NASA SLS block 1,  just for comparison.

Data,  Sources,  and Results for “Standard Low Earth Orbit”


“Standard Low Earth Orbit” is 23 degree inclination out of Cape Canaveral,  Florida,  to a 200 km orbit altitude.  This is what the reported payload delivery capabilities in the literature refer to.  These data are for one-way delivery of payload using a simple payload shroud,  not a recoverable capsule,  except for the Space Shuttle.  As researched,  those data are:

Of these,  the US Space Shuttle,  the Titan IVB,  and Falcon-1 are no longer in service.  There is a demonstrated history of reliability problems with Proton-M.  The Titan-IVB was retired in 2005.  The Falcon-1 retired no later than 2012.  The Space Shuttle retired in 2011.  The prices shown are for fully-expendable flights in the case of Falcon-9 and Falcon-Heavy.  There should be some small price break for flying reusably at reduced payload with these two launchers,  although how much is but speculation. 

The trends of unit cost per delivered metric ton (flying fully-loaded) are given in Figure 1.  Figure 2 shows unit cost per delivered pound.  Data are grouped and correlated as “competitive”,  “non-competitive”,  and “spaceplane.  The “competitive” launchers correlate flying fully loaded as:

                Unit cost $M/metric ton = 10.557 e^(-0.033 Wp)  where Wp = delivered payload, metric tons

                Unit cost $/delivered lb  =   4787 e^(-0.033 Wp)   where Wp = delivered payload, metric tons

The launchers marked “competitive” all compete in the commercial (and military) satellite launch businesses,  with market share in part depending upon price.  The launchers marked “non-competitive” never competed commercially,  and thus were not subjected to severe pressure on price.  The model for these assumes the same -0.033 Wp factor,  and uses a coefficient that forces the curve through the average of the Titan IVB and Delta IV Heavy data points: 

                Unit cost $M/metric ton  =   39.1 e^(-0.033 Wp)  where Wp = delivered payload,  metric tons

                Unit cost $/delivered lb = 17,720 e^(-0.033 Wp)  where Wp = delivered payload,  metric tons

This model was extended to 70 metric tons payload to estimate what should be expected for NASA’s SLS block 1 as shown in the figures ($3.878M/m.ton and $1759/lb).  That calculation corresponds to an expected launch cost of $271M,  when NASA’s actual launch cost estimate is $500M,  and its critics estimate twice that.  So instead of only 3 times more expensive than Falcon-Heavy (otherwise comparable in payload) as predicted by the correlation,  SLS block 1 is likely to be at least 6 times more expensive,  and it might even be 12 times more expensive.

The Space Shuttle (marked “spaceplane”) is quite different,  in that the delivered payload is but a small fraction of the mass of the recovered vehicle.  All the others are one-way trips to space,  with the delivered payload encased in a shroud.  There are no recovered capsules delivered by these launchers. 

The spaceplane model for the Space Shuttle assumes the same -0.033 Wp factor as the “competitive” launchers,  with a coefficient that puts the curve through the data point for the Shuttle:

                Unit cost $M/metric ton  =   131 e^(-0.033 Wp)  where Wp = delivered payload,  metric tons

                Unit cost $/delivered lb = 62,580 e^(-0.033 Wp)  where Wp = delivered payload,  metric tons

Re-Scaling Results for Delivery at the International Space Station (ISS)

I used the payload reduction fraction seen with the Space Shuttle as a constant applied to all the launchers still in service,  for estimating unit cost performance delivering to the ISS.  The ISS is located at a higher inclination and a higher orbit altitude.  For the same launcher technical performance,  a launcher’s max payload capability must be reduced when reaching for the more demanding destination. 

Flying with a 7 person crew,  the Space Shuttle is listed as 24 metric tons to standard low Earth orbit.  It could deliver as much as 27.5 tons,  but only with a smaller crew and less supplies.  Flying with a 7 man crew,  its capability to ISS is reduced to 16 tons.  That is 2/3 of the standard low Earth orbit capability with the same crew and supplies.  Applying this 2/3 factor “across the board” with the same launch prices produces Figures 3 (per ton) and 4 (per pound) below. 

I correlated unit cost estimates to ISS only for the “competitive” launchers that are still in service.  These are (of course) somewhat higher than for “standard low Earth orbit”,  because payload capability is lower,  while launch price is not.  This for one-way payload delivery using a simple payload shroud,  not a recoverable capsule.  That model is:

                Unit cost $M/metric ton = 15.428 e^(-0.048 Wp)  where Wp = delivered payload,  metric tons

                Unit cost $/delivered lb   =    6996 e^(-0.048 Wp)  where Wp = delivered payload,  metric tons

Estimating the Effects of Reusability

I based this estimate on what Falcon-9/Cargo Dragon has demonstrated to ISS with re-use of first stages,  when loaded to max cargo for ISS,  versus what I estimate the fully-expendable deliverable payload is to ISS.  The fully expendable estimate is 15.2 metric tons to ISS.  A fully-loaded (for ISS) Cargo Dragon is 8.8 metric tons.  That ratio is 0.5789,  and I assume it applies to Falcon-Heavy for its payload delivery to ISS with re-use of first stage cores.  The results are given in Figure 5,  for both full price and for an arbitrary modest price break:  80%-of-full-price,  representing savings from re-use. 

Estimating What SLS Block 1 Might Really Do (Standard Low Earth Orbit)

SLS Block 1 is said to deliver 70 metric tons to standard low Earth orbit.  NASA says it expects each launch to cost roughly $500M.  NASA’s critics say each launch might cost nearer $1000M = $1B.  Those data correspond to $7.14-to-14.28M/delivered metric ton or $3239-6478/delivered pound (flying fully loaded). 

The “non-competitive” launcher correlation predicts for SLS Block 1 a unit cost of $3.878/delivered metric ton or $1759/delivered pound (flying fully loaded).  Falcon-Heavy has an almost comparable payload (63.8 vs 70 metric tons),  with unit costs of $1.411M/delivered metric ton or $640/delivered pound (flying fully loaded and fully expendably).  SLS will never be reusable,  as that was never considered as a design requirement. 

SLS is expected to fly only once a year,  and not until 2019 or 2020.  Falcon-Heavy flew its maiden test flight in February 2018.  It is scheduled to fly at least two more times in 2018. 

Other Launchers to Watch For (That Are Not Yet Flying)

There will be an Ariane 6.  Long March 5 may or may not be flying yet.  United Launch Alliance is designing a new heavy lifter to be called Vulcan.  The Jeff Bezos organization Blue Origin is designing a heavy lifter to be called New Glenn.  Spacex is working on a design called BFR which will be a super-heavy-lifter with a fly-back first stage combined with a second stage that is also a reusable spacecraft. 

Final Note:  Falcon-9 Cargo Dragon to ISS

Full price for a Falcon-9 launch is $62M.  This can send to ISS a Cargo Dragon totaling 8.8 metric tons.  Of that,  only 3.310 metric tons is actual deliverable cargo.  Using that 3.31 tons,  the effective unit costs for delivery to the ISS are: 

                $18.73M/delivered metric ton = $8495/delivered pound

Given the same 80% of full price with reusability,  as was used above,  these data reduce to:

                $14.98M/delivered metric ton = $6796/delivered pound

Compare those with what the Space Shuttle costs were,  delivering 16 metric tons to the ISS at $1.5B per launch:

                $93.75M/delivered metric ton = $42,517/delivered pound

These are the best guesses I have for Enhanced Cygnus on Atlas V 551,  and they are not accurate.  The max deliverable mass to ISS is 12.34 metric tons,  which has to be larger than the loaded Cygnus.  Data gleaned from multiple sites on the internet says the max payload to ISS inside the Cygnus is 3.5 metric tons max.  Cygnus cannot return to Earth.  Each launch is $153M.  Those unit costs are thus crudely:

                $46.M/delivered metric ton = $21,000/delivered pound

I have no reliable data on the cargo version of Soyuz,  riding the R-7 rocket.  Best guesses are max 2.4 metric tons of payload in the capsule,  and a launch cost on the order of $65M.  Those unit costs are:

                $27.1M/delivered metric ton = $12,300/delivered pound

Thus,  cargo Dragon on a Falcon-9 appears to be the most cost-effective means to deliver self-maneuvering and self-rendezvousing cargo to the ISS,  of all the vehicles that have done this task.  
Prior Similar Articles

This article replaces earlier postings on this site.  The best of the older postings is “Access to Space:  Commercial vs Government Rockets”,  dated August 7,  2015.  That one compares multiple rockets with the best inflation-corrected costs I could find or devise.  The one prior to that was “Revised Launch Cost Update” dated September 13,  2012.  It refers in turn to “Revised,  Expanded Launch Cost Data” dated May 26,  2012.  That one in turn was a revision to the original “Launch Cost Data” article dated January 9,  2012.  But this current posting is the best,  with the latest versions of the rockets,  and the most current costs I could find.  I did not inflation-correct costs from 2016 to 2018 values.

Figures Follow:


 Figure 1 – Unit Cost Comparison (per ton) to Standard Low Earth Orbit

 Figure 2 – Unit Cost Comparison (per pound) to Standard Low Earth Orbit

Figure 3 – Unit Cost Comparison (per ton) to ISS

 Figure 4 – Unit Cost Comparison (per pound) to ISS


Figure 5 – Unit Costs for Falcon Vehicles as Payload-in-Shroud to ISS with Re-Use