Monthly Archives: November 2014

View 849 Tuesday, November 04, 2014

“I have observed over the years that the unintended consequences of social action are always more important, and usually less agreeable, than the intended consequences.”

Irving Kristol

“Transparency and the rule of law will be the touchstones of this presidency.”

President Barack Obama, January 31, 2009

1030 Wednesday: Hiking with Niven and Barnes.  Back after lunch.   Obama lost.  Republicans would do well to understand that they didn’t exactly win: Obama lost. Now Republicans have an opportunity to show what they are for, and that they are competent, and that they can govern. That will take work, because it is not obvious to anyone including me.  Better than what we have, yes. Well and competent needs to be demonstrated.   Having said all that, Hurrah!

1630 Tuesday Studio City: The polls are still open, and Fox News says that it’s a very close election. It is a very important election. Part of its importance is that there has been a resurrection of conservative Democrats, and that may halt the Democratic party’s race to the extremist liberal/progressive position; but that’s speculation like everything else. An actual repudiation of Obama at the polls would be important. There has already been a political repudiation, with Democrats up for election inviting Obama to support them with money but to stay out of their districts.

I expect that many of the elections will be decided by recounts and decisions about fraud, but that’s speculation too. I’ll have more comments when there is something to comment on.

Here’s an account of the SS2 disaster:

Crash Analysis: How SpaceShipTwo’s Feathered Tails Work

Virgin Galactic’s SpaceShipTwo in its "feathered" configuration, with tails upright. Credit: Virgin Galactic

The cause of the deadly crash of Virgin Galactic’s SpaceShipTwo on Friday remains unknown, but the commercial spaceplane’s feathered reentry system looks to have been involved. Investigators at the National Transportation Safety Board (NTSB) determined that the vehicle’s copilot moved a lever to “unlock” the feather system earlier than planned, and two seconds after the feathers deployed, the spacecraft disintegrated.

The details of how or why this happened are still unclear. The feather system is normally used after SpaceShipTwo has already climbed to the peak of its parabolic flight path and begun to descend, to help the vehicle slow down and stabilize as it flies back to Earth. In fact, the design was one of the major innovations that enabled SpaceShipTwo’s predecessor, the smaller SpaceShipOne, to perform the first manned commercial spaceflight in 2004 and win the $10 million Ansari X-Prize.

SpaceShipTwo has two tails, one pointing straight back off each wing. Each one acts as a rudder, and has a small, horizontal flap at the back, extending to the outside. When the plane is descending, both tails can pivot upright, together, from zero to 90 degrees, so that they stand “vertically” behind the plane. In this configuration, the tails and flaps create drag. This “feathering” effect is similar to that of a shuttlecock in the game badminton. The shapes of both are designed to incite high amounts of drag from air resistance, and both are extremely aerodynamically stable, meaning the drag forces will always end up pushing the plane, or the shuttlecock, into the same orientation (a shuttlecock will always turn to fly cork first, and SpaceShipTwo’s feathered tails ensure it will reenter Earth’s atmosphere at the correct angle).

During a normal flight, SpaceShipTwo is carried upwards by its mothership, WhiteKnightTwo, and released in midair to ignite its rocket engine for the rest of the climb to the edge of space. During all this time, the twin tails point straight out behind its body in the “de-feathered” configuration. When it’s time to make the trip back to the ground, SpaceShipTwo’s pilots can deploy the feather, pivoting the tails upright. When pointed upward, the tails are at right angles to the direction of airflow, creating a huge amount of drag on the vehicle, which slows it down without overheating the spacecraft. This method works because SpaceShipTwo is not coming back from orbit; from the edge of space (it flies to a peak altitude of 110 kilometers) its top speed is low enough that the feather is enough to slow it down safely. Orbital spacecraft return at such high velocities that they require heat shields to protect them.

The feathered design has already proven itself in previous SpaceShipTwo test flights. During one test in September 2011, the spacecraft’s pilots briefly lost control of the vehicle while gliding down to Earth, but regained stability by moving the tails into the feathered configuration.

During Friday’s flight, the pilots normally would have deployed the feather when the space plane had reached a speed of Mach 1.4 (1.4 times the speed of sound) during descent, but the copilot Michael Alsbury unlocked the rudders early, when SpaceShipTwo was going Mach 1.0, according to NTSB Acting Chairman Christopher Hart. That action alone should not have been enough to pivot the tails upright, however, because neither pilot took the further step of turning the feather handle to actually move them, Hart said. Somehow, the tails rotated upward anyway, and the increase in drag at this point in the flight proved disastrous.

It is now clear that the Virgin Galactic SpaceShip Two was torn apart by aerodynamic forces after the ship entered the “feathered” “reentry” mode while still in powered flight beginning its vertical ascent to whatever maximum altitude the mission had planned. The hybrid engine worked as planned, and survived the destruction of the craft.

We can conclude with some confidence that what happened was that very early in the powered flight of SS2 when the ship was still at the breakaway altitude – 30,000 feet or so – the locking bar that keeps the “feathers” from swiveling was released. The ship was at something above Mach 1 at 30,000 feet.

This is at about ¼ atmospheric density at sea level so call it 250 millibars pressure, and the ship is moving above Mach 1. It is not clear why the feathers, which were now free from constraint, would rotate, but SS1 was designed to be a shuttlecock when the feathers are deployed, and to remain aerodynamically stable while moving through the atmosphere in that condition. The control surfaces on the feathers are presumably designed that way, and apparently, so soon as the feathers were free to rotate, they did so.

This would rotate SS2 to try to fly with its belly to the direction of air resistance, making for the stable shuttlecock attitude as the ship falls into the atmosphere at what I have been told is a velocity of Mach 1.4 or so; but note that in that situation the engine would be off, having burned all its fuel to get SS2 to altitude above 100,000 feet. Unfortunately, the engine, was still working, and would be trying to push the ship forward nose first, not at a high angle of attack. The resulting stress would be resolved by tearing the ship apart while the engine continued to thrust. What angle of attack it would now resume (so long as the engine continued to operate) isn’t easy for me to visualize, and I don’t know how long the engine ran, but by then SS2 was no longer under control. One observer has told me that “pieces fell off and then it came down like a lawn dart.”

I am appalled to hear that NTSB estimates it will take them more than a year to complete their report, and meanwhile any replacement of SS2 will not be allowed to fly. It’s pretty clear that this was an accident easily prevented, either by better control design – I’d be glad to do the human factors engineering if asked, but there are surely plenty of engineering psychologists with more recent experience than mine – coupled with better operations instructions. We can speculate on why the copilot – who perished in the crash – unlatched the bar that keeps the feathers secure, but we can be pretty sure no one will ever make that mistake again.

NTSB should issue the report by the end of the year so that Sir Richard Branson can get to work replacing SS2 and getting Virgin Galactic back on schedule. SS2 was never going to be a pathway to suborbital flight. It won’t get us to Tokyo in two hours, nor will any of its descendants. But it will give us operational experience in near earth space. A ship harbor is supported by harbor sightseeing cruises as well as by ocean liners.

2300. Alaskan polls close with Republicans ahead in the Senate race there.  The Republicans will have at least 52 Senators, and have gained 12 seats n the House. The country has repudiated Hope and Change and The One You’ve Been Waiting For.  Now it is up to the Republicans to show they can actually accomplish something.

Before that, there may be a Constitutional crisis, as Obama attempts to use his Executive powers.  He may try an amnesty move, and he will almost certainly try for a series of judicial and executive appointments while he can count on a Senate majority.  This will not sit well with many.  November, December, and early January may be very interesting times, and after that there will still be the Executive Powers.

“Do we falsify the resume? Yes, we do. We call it ‘spicing of the resume’.”

<http://www.theguardian.com/us-news/2014/oct/28/-sp-jobs-brokers-entrap-indian-tech-workers>

—-

Roland Dobbins

It’s late and the election is over.  Time now to devise an actual program. It is not clear that the establishment Republicans know how to do that, but we can hope.

Freedom is not free. Free men are not equal. Equal men are not free.

View 849 Sunday, November 02, 2014

All Souls Day

“I have observed over the years that the unintended consequences of social action are always more important, and usually less agreeable, than the intended consequences.”

Irving Kristol

“Transparency and the rule of law will be the touchstones of this presidency.”

President Barack Obama, January 31, 2009

Tuesday will be one of the most important elections of this Millennium. A Republican win will not be decisive over time, because it will not be a mandate: a Republican win will be a public objection to the leftward plunge of the Democratic Party. Unfortunately it will be construed by Establishment Republicans as a great deal more than that, and that will cause problems, but they are soluble problems. A Republican Thumping – unlikely given the polls – would be a disaster for the cause of limited government. If the big government party can win despite the sheer incompetence of the past few years, the Republic will have to sink very low indeed before it can turn back from centralization and control by increasingly arrogant and incompetent bureaucracy.

It appears that the Ebola threat remains under control. Little of that control is due to competence. We do not really have an understanding of all the strains of Ebola, the mutation rate that could follow a large outbreak of the virus in a hitherto unfamiliar host environment, or indeed all the transfer mechanisms. We have been fortunate enough to find that the general theory – that the virus can become virulent only after it so infects the human host that obvious symptoms are displayed – has so far been predictive. Of course it is very much in the interest of the virus to be transmitted before any visible symptoms are displayed; or if you prefer, the strains of the virus that can infect before the host subject displays symptoms have a far higher chance of survival; that would be a far more ‘fit’ virus than one that has to render the host half dead before it can spread to a new host.

We are betting heavily that such mutations are not taking place in this current outbreak. I have no way to estimate the probabilities here, and wouldn’t even with a great deal more data on what’s going on in West Africa. The Administration theory is that quarantine is an ineffective strategy. We are better off fighting the disease in Africa than in the United States, and putting difficulties in the way of physicians returning from the plague area will discourage them from going there at all. These are, after all, trained professionals and they will act properly.

The behavior of several of these professionals indicates that they are very certain that they can’t be contagious before displaying symptoms, and they believe this so strongly that they feel justified in defying any instruction to the contrary. We can hope that none of the medical professionals who go to the plague zone encounter a different strain that has an altered cycle of infectivity. Had some of the previous professionals encountered such a strain, the effects might have been catastrophic.

The United States continues to break things and kill people in the Middle East without a discernible objective other than trying to stave off disasters. We send our air power where the enemy chooses. Allowing the other side to issue marching orders to your soldiers has not been a winning strategy since Demosthenes warned the Athenians against it in one of the Philippics.

So you, if you hear of Philip in the Chersonese, vote an expedition there; if at Thermopylae, you vote one there; if somewhere else, you still keep pace with him to and fro. You take your marching orders from him; you have never framed any plan of campaign for yourselves, never foreseen any event, until you learn that something has happened or is happening.

Demosthenes.

There are a few voices raised in favor of building a US Air Base in Kurdish Iraq. I think I first suggested this a year ago, and it still seems like a good idea. The whole thing proceeds slowly http://www.presstv.ir/detail/2014/10/23/383335/us-to-take-iraq-airport-as-military-base/ and half heartedly, but then the President is very reluctant to commit more forces to Iraq, particularly before the election.

ISIL AKA The Caliphate is our enemy, but is also the enemy of several of our enemies. The destruction of the Caliphate is not possible without a greater commitment of forces than any American administration including a Republican one is likely to send; but securing Iraqi Kurdistan can be accomplished with tactical air power and a brigade of ground forces. Moreover, the same forces could keep Baghdad from falling to the Caliphate, and while the tactical air elements would have to remain American, a good part of the ground element could be created from existing Kurdish forces with US equipment and training. Indeed we might even recapture some of the American equipment given to the Baghdad regime and thrown down in terror for ISIL to pick up and use…

Two major events in space development: the failure and destruction by range safety of an Orbital Sciences rocket carrying supplies and experiments to the International Space Station, and the destruction of the Virgin Airlines SpaceShip Two in the Mohave Desert. The most significant of these was clearly the SS-2 which was destroyed in mid-air.

SpaceShipTwo (SS2), the plane on which the Virgin boss Sir Richard Branson has pinned his hopes of sending commercial passengers to the edge of space at a cost of $250,000 (£156,000) each, broke up during a test flight at about 45,000ft on Friday. The pilot, Peter Siebold 43, managed to parachute to the ground and was described as alert though with serious injuries; the co-pilot, Michael Alsbury, 39, was killed.

http://www.theguardian.com/science/2014/nov/02/virgin-galactic-spaceshiptwo-crash-investigators-fuel-warnings

In actuality, the SS-2 loss, though both spectacular and tragic, was the less significant in all ways other than public perception. The Virgin Galactic space tourism venture is important to commercial space development because it is a path to making money in space, and such commercial activities are needed so that private space investments will continue. If there’s no clear way to make a profit, few people will invest in space activities. A number of people have invested a great part of their lives in trying to develop such activities, and they are to be commended; but space won’t be conquered by heroes and heroines alone. It also takes money and a lot of it.

The Virgin Galactic route to space begins and ends with tourism: going to space, spending a little time there, and coming home. The SS-2 and its successors are airlaunched at 30,000 feet and rocket to space – however high we define “space” to begin – then fall like a badminton shuttlecock into the atmosphere and glide down to a landing. There is no path from this performance to actual spacefaring. Even if SS-2 reaches 100 miles altitude – Low Earth Orbit altitude – it hasn’t “gone orbital” nor could it ever. It’s actual velocity when it reaches maximum altitude is effectively zero, and it falls into the thickening atmosphere at subsonic speeds. This is not “reentry” as an orbital or sub-orbital craft would experience it. The thermal protection problems are not the same, nor are the control and stability problems.

Moreover the hybrid motors of SS-1 and SS-2 could never be built large enough to give the craft appreciable velocity. It can never go orbital.

These craft can make money from space tourism. One can hope the income stream will continue long enough to make the ventures profitable. But they don’t lead to becoming a spacefaring nation.

I have for some years been dubious about the safety of the hybrid engines. I first encountered them when I accompanied the late George Koopman out to his American Rocket Company test site at Edwards for a test firing. The system chugged. Hybrid engines consist of a cast solid fuel block into which an oxidizer is introduced. The fuel is exceptionally safe and stable. It won’t blow in manufacture or storage. If it catches fire it burns. It’s only in a confined place with a powerful oxidant that it becomes rocket fuel. There is a lot to recommend them, including the elimination of fuels tanks and pumps.  The oxidant needs to be supplied from tanks, but not the fuel which burns in place.

The problem with hybrid engines is that the burning takes place on the surface of the fuel. If a piece of the fuel breaks loose from the rest, it burns all over, producing a sudden temporary increase in pressure. If this happens several times it is called chugging, and it makes the flight difficult to control. Something of this sort happened during the X-Prize flights conducted by Scaled Technology.  The hybrid engines won the X-prize, but it was close in the second flight.

If a large enough piece breaks off it can block the flow of rocket exhaust out of the combustion chamber. Pressure rises, and with luck blows the errant fuel chunk out the back and; but if the chunk is too large, the overpressure in the combustion chamber can get too high, rupturing the chamber. Or the pressure can force the propellant to crack, exposing more surface area to the oxidant; more fuel burns. There are other scenarios leading to from mild to catastrophic damage to the spaceplane’s structure.

In my judgment this is likely what happened to SS-2.

http://www.theguardian.com/science/2014/nov/02/virgin-galactic-spaceshiptwo-crash-investigators-fuel-warnings

Note that I have long been critical of the hybrid engine concept. There are other views.

http://online.wsj.com/articles/virgin-galactic-crash-probe-focuses-on-possible-structural-failure-1414972644

[1100 Monday 3 November update: there is considerable evidence that the SS2 was brought down by a flight control problem, not any failure of the engine.]

I would think this is not the end of Virgin Galactic. Sir Richard Branson is a determined man of great courage. It is not the end of man in space, or of commercial space. But it will be used as ammunition for those who want to put all control of such activities in the hands of a bureaucracy.

We lost Grissom, White, and Chaffee and continued. The star road takes its toll.

http://www.jerrypournelle.com/images/phoenix.mp3

[2300 Sunday 2 November]: I am reluctant to get involved in breaking news for the obvious reason that one ends up commenting on stuff only to discover that it isn’t relevant.  My dislike of hybrid engines may well have led me to say more about their problems than is warranted by this incident: I am now getting the story that there may have been control error involved in this.  The feathering system for use in the vertical reentry to the atmosphere may have been activated while the ship was under rocket power.  This would far overstress the structure of the craft, so that it literally tore itself apart. There appears to be some evidence of this found in the wreckage; but again this is speculation in the absence of important information.  I am reluctant to report rumors.

The cause of the crash of SS2 is not yet determined.

Freedom is not free. Free men are not equal. Equal men are not free.