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#1 2005-02-19 00:22:38

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

NASA's IBEX mission is another of those faster, cheaper (under $150 million), simpler launches scheduled for a lift off in 2008 (or perhaps 2028). It's a serious probe and deserves a serious launch vehicle. NASA is going to provide a Pegasus.

I could be mistaken, and often am, but I remember the Pegasus as being a Navy missile from the 1960's or earlier. And the name of it, Pegasus, reminded me of an old Nova program, Death Star.

This is a snip of the transcript of that program:


NARRATOR: But in 25 years, no one had ever caught an afterglow. They must be fleeting. Astronomers needed to train their telescopes at the bursts much more quickly. They pinned their hopes on an explorer satellite called HETE.

DON LAMB: So the key ideas about the High Energy Transient Explorer, HETE, were that it would very accurately pinpoint the locations of the bursts and then share that with the community in near-real-time.

DALE FRAIL: So they'd detect the gamma ray burst and then they could give us a position accurate enough to point our very best telescopes at that position, so we could bring out our big guns if you like.

NARRATOR: After years of arguing over the origin of the bursts, astronomers thought HETE was the tool they needed to end the debate.

In November 1996, HETE took off from an airbase in Virginia. To the dismay of HETE scientists, NASA insisted on deploying the satellite from a Pegasus rocket strapped to the belly of a converted airliner. In previous launches, the Pegasus rockets had suffered a 40 percent failure rate.

DON LAMB: We said, "Look, we've spent a decade designing and building the satellite and now you're asking us to take a launch on a rocket that's shown, so far, to be very unreliable." And the answer that came back from NASA was, "You either take this ride now, or we close the program."

[On Tape] Peg is go. Peg is go.

DON LAMB: So the moment came when the aircraft, you know, says, "On my mark, launch. Three, two, one..."

[On Tape] Three, two, one...Drop.

DON LAMB: The rocket, it just dropped from the aircraft. And your heart's pounding and you're waiting because it will only ignite five seconds later. So you're counting to yourself.

[On Tape] Pegasus is away. Standing by for ignition...and Pegasus is up and burning.

DON LAMB: Ah, wow. You know that the first stage is ignited and it's headed for orbit so everything was going well and we were hearing, "We have first stage burnout."

[On Tape] ...burnout in approximately...now.

DON LAMB: "We have second stage separation. We have second stage ignition." And everything, all the telemetry...and you hear all these voices, of all the mission controllers who are monitoring and telling you how things are going. And we had third stage separation and just as that happened I just caught some person in the control room said, "We have an anomaly in the third stage bus."

[On Tape] This is Pegasus launch, stat. It looks like the transient bus has gone down. The transient bus has gone down.

DON LAMB: The other people in my office didn't understand what was going on, so they were still excited, and yet I was starting to feel this dread that something was terribly wrong.

[On Tape] ...and we appear to have a problem


And, of course, the mission was lost and the Pegasus failure rate racked up another few percentage points. I can't imagine NASA, or anyone else for that matter, using launchers that fail 40% of the time. Even the shuttle is safer.

I've read an article here that suggests the use of less reliable and less expensive rockets when the survival of the payload is not that important, that is, it's no big deal if a few loads of water and dried beans are lost because an inexpensive missile detonated under (or over) the aircraft carrying it.

I'm not buying that rationale. What engineer would want to sign off on a launch knowing those kinds of odds? This could be another black eye for NASA.

It's common knowledge that Earth is already surrounded by all manner of debris. We don't need any more junk up there. Is NASA simply clearing out its closets and disposing old launch vehicles?

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#2 2005-02-20 00:45:11

GregM
Member
Registered: 2005-01-16
Posts: 30

Re: Running on Empty - NASA launches with a wing and a prayer

Maybe I could add a few things.

Firstly, the “Pegasus”  space launch vehicle (SLV) was developed by a company called Orbital Sciences Corporation in the mid-to-late 1980’s. The first successful launch was in 1990. It was designed from the outset as a vehicle to put spacecraft into space, and is still operated by OSC to this day. Customers (such as NASA) pay OSC to launch their spacecraft into orbit in the same manner as customers pay other companies such as International Launch Services, Lockheed-Martin, and Arianespace to put their spacecraft into space.  From 1990 through to 1996 (the period in question from the HETE case sighted), the Pegasus had an 80% success rate in 10 launches to date. Not a great success rate, but not a disaster for the first 10 launches Development problems are to be expected to some degree (and essentially the vehicle was still in development at that time). An 80% rate for a mature SLV program would be considered not very good. As a comparison, the Delta 2 program (a very mature SLV program) had a 97% success rate from 1989 through to 1998 in 67 launches. Currently, the Pegasus success rate is 91%, a little short of the 95-98% success rate of launchers generally considered very successful.

Secondly, other than having the same method of propulsion (solid rocket motors), Pegasus has no relationship to the “Polaris” and its follow-on “Poseidon” sea-launched ballistic missiles (SLBM) that I believe that you are confusing the Pegasus with. These missiles were designed as weapons of war, intended to throw thermonuclear warheads many thousands of kilometers in a sub-orbital trajectory to targets in the Soviet Union and East Bloc.  Polaris was designed in the late 50’s and early 60’s, and it’s replacement Poseidon in the late 60’s and early 70’s. Poseidon was retired and replaced by the “Trident” SLBM many years ago. If any of these missiles are being used in anything but the occasional reliability test, it literally means that the end of the world is coming in 30 minutes or less.

Thirdly, comparing the Pegasus with the Space Transportation System (STS) (commonly known as the “Space Shuttle”) is unfair in terms of successfully launching things into space.  Despite all the badmouthing that the Shuttle has received in the past few years, it is without exception one of the most successful SLV’s ever developed and flown in quantity, with a launch success rate in excess of 99%. The reason for the Shuttle’s excellent launch success rate is singular: it is a crewed vehicle that requires a “man-rating”. “Man-rating” is a much more stringent reliability requirement than for regular SLV’s for obvious safety reasons.  The Shuttle also has one other need for extreme launch reliability: it has no escape system for the crew in the event of a catastrophic launch failure.

Only a very small handful of SLV’s have 100% launch success ratings (such as the Saturn family of SLV’s). These vehicles were however flown only a very few number of times, so they cannot be compared to a mature family of SLV’s such as STS, Delta, Semyorka, Proton, or Ariane – all with over 100 launches per family. The only mature launch vehicle with a perfect record is the “Altas 2”, which was retired a few weeks ago with 68 launches.

Lastly, your general observations concerning “better, faster, cheaper” missions are spot on – but do not go far enough. Spacecraft  projects of this class (often called “Discovery” class missions by NASA) are of the low budget (in terms of spaceflight) variety.  The spacecraft often are built with off-the-shelf hardware, have a relatively small project staff compliment, and relatively short development times. Project costs are usually capped at $150 million or less. This usually means less redundancy (read reliability) in the spacecraft, shorter missions, and very narrowly focused objectives. Often, one of the largest single costs to any mission is the launch costs, so in this class of mission the launch costs are kept to an absolute minimum as well as the other aspects. This is done by selecting as small a launch vehicle as possible, therefore dictating as small a spacecraft as is possible to carry out the mission (HETE=124kg). The point that I’m trying to illustrate here is that these types of missions are inherently filled with more risk than other missions. This is not true with just the launch phase, but rather the whole mission.

The question you need to ask is if “better, faster, cheaper” Discovery class missions are worth it.  The launch vehicle itself is brand new.

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#3 2005-02-20 22:42:52

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

Thanks. It's nice to get a response.

It appears that there are two distinctly different Pegasus launch platforms! The producers of that Nova program or the scientists involved must have been mistaken.

My earliest, perhaps erroneous, memories of Pegasus was from a model of old missiles that I glued together as a child. The kit also contained models of the Redstone missile, Atlas, and one named Snark. I never did finish the display, preferring to "fly" the models around the alien terrain of my bed blankets. The SR71 model was everyone's favorite. We were kids.

Regarding the ICBMs Polaris and Poseidon, I wrote nothing about them and have not confused them.

As to the shuttle having a launch success rate in excess of 99%, that's better than 2 out of 200. Have there been over 200 shuttles launched?

STS can also be seen as a program that has lost two flight crews and 40% of the fleet. I don't know about you, but every time a shuttle launches I get white knuckles and sweat.

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#4 2005-02-21 00:35:44

hubricide
Member
Registered: 2004-07-26
Posts: 49

Re: Running on Empty - NASA launches with a wing and a prayer

I don't know that going into space will ever exactly be 'safe'.  Huge amounts of power are needed to even go into orbit, and any tiny problem will probably end in a not-so-tiny result.  As long as everyone involved knows the risks, I say go for it.

As far as IBEX goes, I hope it succeeds, but NASA's 'cheaper faster better' theory hasn't been a stunning success thus far..

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#5 2005-02-23 17:05:30

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

We all have our first chance of stumbling when we crawl out of bed each day, but we continue to do it, every morning. But the odds in question here, be they 40% or 20% launch failure, depending on the source of information, are not insignificant.

I have not been able to locate any stats that include the percentage of failed Pegasus launches vs those that have been successful. All I have are the original quotes given in the Nova program. Granted PBS is not infallible, but it would be nice to address news that is more timely.

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#6 2005-02-23 17:20:37

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Running on Empty - NASA launches with a wing and a prayer

"STS can also be seen as a program that has lost two flight crews and 40% of the fleet. I don't know about you, but every time a shuttle launches I get white knuckles and sweat."

Again, this isn't terribly fair if you are comparing Shuttle to a throw-away rocket if all you are doing is launching probes. If you look at it that way, then there is a 100% chance of all expendable rockets being lost. If you compare mission sucess rates, Shuttle is pretty good.

Shuttle has a good reccord compared to most rockets, it is simply held to an extremely high standard because it carries people, and since they are effectively irreplaceable.

If HETE didn't fly on Pegasus, it wouldn't have flown at all either, since no other available rocket would have been cheap enough to meet the $150M budget.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#7 2005-02-26 19:22:52

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

The question you need to ask is if “better, faster, cheaper” Discovery class missions are worth it.  The launch vehicle itself is brand new.    
   
Faster, perhaps, cheaper, most certainly, but better? That's too generous.

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#8 2005-02-28 02:16:03

Stephen
Member
Registered: 2004-01-16
Posts: 68

Re: Running on Empty - NASA launches with a wing and a prayer

We all have our first chance of stumbling when we crawl out of bed each day, but we continue to do it, every morning. But the odds in question here, be they 40% or 20% launch failure, depending on the source of information, are not insignificant.

Uh, a 20% launch failure rate would suggest that 20 out of every 100 launches ended in failure. Similarly, a 40% failure rate would mean that almost half had failed!

I rather doubt that is what you were intending to say. smile

With over 110 shuttle flights--that figure, BTW, is taken from here and here --the loss of two flights would put the failure rate of somewhat under 2%.

True, there are only a small number of shuttles, two out of 5 (ie not counting "Enterprise") of which (40%) have been lost. But that is not a "launch failure" of 40%! The Challenger, for instance, had 9 successful launches before it exploded in 1986. The Columbia had nearly 30.


======
Stephen

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#9 2005-02-28 09:23:10

djellison
Member
From: Leicester,UK
Registered: 2004-08-31
Posts: 113

Re: Running on Empty - NASA launches with a wing and a prayer

We all have our first chance of stumbling when we crawl out of bed each day, but we continue to do it, every morning. But the odds in question here, be they 40% or 20% launch failure, depending on the source of information, are not insignificant.

Uh, a 20% launch failure rate would suggest that 20 out of every 100 launches ended in failure. Similarly, a 40% failure rate would mean that almost half had failed!

I rather doubt that is what you were intending to say. smile

With over 110 shuttle flights--that figure, BTW, is taken from here and here --the loss of two flights would put the failure rate of somewhat under 2%.

True, there are only a small number of shuttles, two out of 5 (ie not counting "Enterprise") of which (40%) have been lost. But that is not a "launch failure" of 40%! The Challenger, for instance, had 9 successful launches before it exploded in 1986. The Columbia had nearly 30.

Actually - the shuttle has a <1% launch failure - only Challenger failed during launch.  Columbia is a <1% entry failure

Doug

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#10 2005-02-28 10:33:45

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

Uh, a 20% launch failure rate would suggest that 20 out of every 100 launches ended in failure. Similarly, a 40% failure rate would mean that almost half had failed!

I rather doubt that is what you were intending to say.

No, that's what I'm saying. The 40% failure rate came from a Nova program and the 20% figure can be found in the first reply to this topic. I don't know the source of the 20% figure.

This topic was originally about the Pegasus rocket, but when I said that the shuttle was safer than the Pegasus, I caught a lot of flak for making the comparison.

That said, I will stand with my observation that the shuttle program has lost two flight crews and 40% of the fleet. I would not double the stats by claming that that the program lost one at launch and another while attempting to land. However a person wants to evaluate the shuttle program, the bottom line is two dead flight crews and two lost shuttles. No tricky arithmetic is necessary. Nothing survived. I think (or hope) that NASA is looking at the bottom line too.

I would make the same observation about the Concorde.

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#11 2005-03-01 05:32:01

Stephen
Member
Registered: 2004-01-16
Posts: 68

Re: Running on Empty - NASA launches with a wing and a prayer

Uh, a 20% launch failure rate would suggest that 20 out of every 100 launches ended in failure. Similarly, a 40% failure rate would mean that almost half had failed!

I rather doubt that is what you were intending to say.

No, that's what I'm saying. The 40% failure rate came from a Nova program and the 20% figure can be found in the first reply to this topic. I don't know the source of the 20% figure.

This topic was originally about the Pegasus rocket, but when I said that the shuttle was safer than the Pegasus, I caught a lot of flak for making the comparison.

That said, I will stand with my observation that the shuttle program has lost two flight crews and 40% of the fleet. I would not double the stats by claming that that the program lost one at launch and another while attempting to land.

Those 40% & 20% stats have less to do with the failure rate of NASA's shuttles than the fact that NASA has only ever had 5 of them. Had 50 shuttles been built instead of 5, the loss of two would mean the statistic you would now be invoking would be 4% rather than 40%.

Furthermore, it would remain 4% even if there had only ever been two flights and NASA lost a shuttle each time one went up! Yet which figure would you consider the more alarming, the loss of 4% of the shuttle fleet or that launch failure rate of 100%?

Back in the real world, NASA may have lost 40% of the fleet rather than a mere 4% but if you go up in a shuttle you have a less than 2% risk of not surviving the trip, at least due to accidents during launch or reentry.

However a person wants to evaluate the shuttle program, the bottom line is two dead flight crews and two lost shuttles. No tricky arithmetic is necessary. Nothing survived. I think (or hope) that NASA is looking at the bottom line too.

I would make the same observation about the Concorde.

No form of transport known to man is 100% safe. Horses bolt, cars plough into power poles, aircraft collide, and rockets have been known to explode. However, some accidents are more survivable than others simply because of the nature of the accident. If two cars collide on a road, for example, those on board may well survive the incident. On the other hand, if two planes collide in mid-air chances are they won't.

You mentioned the Concorde. Back in 1977 two Boeing 747s, one taxiing and one in the act of taking off, collided on a foggy runway on Teneriffe. Over 550 people were killed. Miraculously about 60 survived. Significantly, however, all the survivors were from the taxiing jumbo. Nobody survived from the plane in the act of taking off. Had both those planes been in the act of taking off when they collided, or been in the air, chances are nobody would have survived on either plane.

Just as nobody survived the Concorde, Columbia, or Challenger accidents.

The reason is obvious. Launch & re-entry are the most dangerous times for any spacecraft, just as takeoff & and landing are for aircraft. The next time NASA or anybody else loses a manned spacecraft on launch or reentry expect there to be a 100% casualty rate then too--just as there would almost certainly be no survivors the next time two planes collide in mid-air. Or for that matter collide with tall buildings or plough into the ground as in the case of those 9/11 aircraft.

It is the nature of the accident that contributes to that 100% casualty rate. You can try to make launch and reentry safer by making the launch & reentry systems more reliable. Alternately, you might find ways for problems to be detected and fixed before they become a problem. If, however, such systems do fail then I'm afraid you will have to expect there will be no survivors.


======
Stephen

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#12 2005-03-01 06:04:28

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 17,741

Re: Running on Empty - NASA launches with a wing and a prayer

Sort of reminds me of all those car crash dummy commercials in a way. Making the crew carrying or passenger area of a rocket safer for some types of re-entry or launches can be done but it will carry with it the burden of having less ability to deliver payloads to space. Had either cabin been re-enforced just a little more, the possibly would have been survivers in both cases. Granted maybe not all but some is better than none.

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#13 2005-03-01 14:08:42

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

No one could fault the 747s that were lost in the Tenerife tragedy. It was human confusion that killed those people. I don't see the analog. Pilot error was not a factor in the deaths of the two shuttle crews.

It's unfortunate the shuttle doesn't have the same safety record that commercial aviation has. If 747s were dropping out of the sky 40% of the time, no make that 20%, 10%, 1%, no make it .01% of the time, due to design and not human error, the fleet would be grounded after a few accidents.

Now, when (if) the shuttle returns to service and another disaster, or say near disaster occurs, even if the crew survives, that's the end of the shuttle program. NASA could not and would not surmise that the shuttle was just a little less safe, under 3% lost, or what have you, name your percentage. The program would end. NASA and the public would look at three lost spacecraft, not this percentage or that percentage, the two remaining shuttles would be retired to museums, and rightly so. That's reality. 

It doesn't matter that most of us would give their right gonad for a chance to get into space.

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#14 2005-03-01 20:04:48

hubricide
Member
Registered: 2004-07-26
Posts: 49

Re: Running on Empty - NASA launches with a wing and a prayer

It's unfortunate the shuttle doesn't have the same safety record that commercial aviation has. If 747s were dropping out of the sky 40% of the time, no make that 20%, 10%, 1%, no make it .01% of the time, due to design and not human error, the fleet would be grounded after a few accidents.

Maybe I'm pointing out the obvious, but what 747s do is inherently far less dangerous than what the space shuttles do.  Surely you realize this?

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#15 2005-03-01 20:12:44

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

I will admit that there is a bit of devil's advocacy going on here, but regardless, another loss and the party's over.

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#16 2005-03-02 01:15:52

Stephen
Member
Registered: 2004-01-16
Posts: 68

Re: Running on Empty - NASA launches with a wing and a prayer

No one could fault the 747s that were lost in the Tenerife tragedy. It was human confusion that killed those people. I don't see the analog. Pilot error was not a factor in the deaths of the two shuttle crews.

The point of mentioning the Teneriffe tragedy was to point out the difference in the survival rates. Despite the horrific loss of life, some people survived. However, they only survived if they happened to be a passenger on the plane moving down the runway at a few miles per hour. There were no survivors from the one careering down the runway at full belt.

You would have to expect the same thing would occur with a shuttle plummeting earthwards at hundreds of miles an hour.

It's unfortunate the shuttle doesn't have the same safety record that commercial aviation has.

Two shuttles have been lost in fatal accidents in a little over 20 years. How many models of commercial aircraft can boast that record?

If 747s were dropping out of the sky 40% of the time, no make that 20%, 10%, 1%, no make it .01% of the time, due to design and not human error, the fleet would be grounded after a few accidents.

As I understand it aircraft of the same model are grounded, at least in cases where investigators suspect the cause to be due to mechanical or airframe problems. (In those circumstances to allow similar craft to stay in service would be irresponsible.)

The reason such groundings does not impact as much on world air travel is that the world's air travel industry is not dependant on a single make or model of aircraft.

Imagine what would happen if the only kind of aircraft in service (at least in non-Russian airlines smile  were Boeing 747-400 series planes and all those planes had to be suddenly grounded due to an air tragedy...

NASA's folly was to put almost all its eggs in one shuttle-shaped basket. It had no contingency plan in place for dealing with vehicle losses. As far as I can see it still does not. In fact it is again putting all its eggs in one basket with this plan to retire the shuttles to make way for this new gee-whiz CEV, just as the arrival of the shuttle led to no more Saturn Vs being built. Sooner or later one of the CEVs is going to be lost due to an accident. That is an inevitability. It may not happen for a decade or two, but it will happen eventually. No one can guarantee 100% reliability, any more than anyone can guarantee that there will be more fatal aircraft incidents. When the tragedy happens all the remaining CEVs will probably be grounded, just like all the remaining shuttles were grounded after the Columbia accident. Imagine what is going to happen should there be, by then, human beings at a base on the moon dependant on those CEVs to deliver supplies.

Now, when (if) the shuttle returns to service and another disaster, or say near disaster occurs, even if the crew survives, that's the end of the shuttle program. NASA could not and would not surmise that the shuttle was just a little less safe, under 3% lost, or what have you, name your percentage. The program would end. NASA and the public would look at three lost spacecraft, not this percentage or that percentage, the two remaining shuttles would be retired to museums, and rightly so. That's reality.

No, the reality is that NASA only has three shuttles left, with no prospect of Congress funding the construction of any more. (The CEV is now seen as the great white hope for American human spaceflight.) The loss of another would leave only two left, imposing a further burden on maintaining its schedule.

As to your views about NASA (and/or Congress and/or the president) retiring the remaining shuttle post-haste should a third shuttle be lost, I take it you will also be expecting the same three-fatal-crashes policy be applied to aircraft and motor cars. If (say) three Boeing 747s over a 20 or 30 years period, or three Toyota Camrys crash over such a period, with the loss of all onboard, those models should be immediately withdrawn from sale, the skies, and the roads. To paraphrase your words, "the public would look at three lost [aircraft or motor cars], not this percentage or that percentage".

In other words, it would not matter one iota that there were hundreds of 747s and millions of Camrys in service, the vast proportion without any fatal accidents. What would matter more was the loss of those three.

If on the other hand that is not the sort of policy you would want to see applied to aircraft or motor cars, why then should anyone insist it be applied to the shuttle? (And, presumably, to the CEV when it comes into service.)

Thousands of people die on the world's roads every year. Hundreds die in plane accidents. Yet the cars stay on the roads and the planes still fly, with the crashed ones replaced and faults in the remainder fixed (often via expensive mass recalls in the case of cars).


======
Stephen

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#17 2005-03-02 12:52:02

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

True, there are only a small number of shuttles, two out of 5 (ie not counting "Enterprise") of which (40%) have been lost. But that is not a "launch failure" of 40%! The Challenger, for instance, had 9 successful launches before it exploded in 1986. The Columbia had nearly 30.

Is this something to boast about?

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#18 2005-03-02 19:18:47

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

Two shuttles have been lost in fatal accidents in a little over 20 years. How many models of commercial aircraft can boast that record?

Does that mean percentages are irrelevant because there are only 5 shuttles to be lost, that is, each launch is worth 1/5 of the fleet Vs the much smaller percentage of commercial aircraft because there are so many of them?

Over a course of 20 years I would say none of the shuttles saw much action compared to any 747 over the same amount of time. They spent most of their lives in hangars while technicians tinkered with them. 

NASA's folly was to put almost all its eggs in one shuttle-shaped basket. It had no contingency plan in place for dealing with vehicle losses. As far as I can see it still does not. In fact it is again putting all its eggs in one basket with this plan to retire the shuttles to make way for this new gee-whiz CEV, just as the arrival of the shuttle led to no more Saturn Vs being built. Sooner or later one of the CEVs is going to be lost due to an accident. That is an inevitability. It may not happen for a decade or two, but it will happen eventually. No one can guarantee 100% reliability, any more than anyone can guarantee that there will be more fatal aircraft incidents. When the tragedy happens all the remaining CEVs will probably be grounded, just like all the remaining shuttles were grounded after the Columbia accident. Imagine what is going to happen should there be, by then, human beings at a base on the moon dependant on those CEVs to deliver supplies.

I have never argued that 100% reliability is a mandate. Indeed, there would be no statistics to quibble over if you don't begin launching at some point in time. Should the first mission fail, for whatever reason, yes, the failure rate would be 100% at that point in time. How could it be otherwise?


No, the reality is that NASA only has three shuttles left, with no prospect of Congress funding the construction of any more. (The CEV is now seen as the great white hope for American human spaceflight.) The loss of another would leave only two left, imposing a further burden on maintaining its schedule.

I would argue that there would be no schedule to maintain.

As to your views about NASA (and/or Congress and/or the president) retiring the remaining shuttle post-haste should a third shuttle be lost, I take it you will also be expecting the same three-fatal-crashes policy be applied to aircraft and motor cars. If (say) three Boeing 747s over a 20 or 30 years period, or three Toyota Camrys crash over such a period, with the loss of all onboard, those models should be immediately withdrawn from sale, the skies, and the roads. To paraphrase your words, "the public would look at three lost [aircraft or motor cars], not this percentage or that percentage".

In other words, it would not matter one iota that there were hundreds of 747s and millions of Camrys in service, the vast proportion without any fatal accidents. What would matter more was the loss of those three.

It has been argued in this topic that it is not fair to compare the two or three lost shuttles to commercial aviation because there are many aircraft and only 5 shuttles.

Now, it is argued that two or three lost aircraft or cars are relevant even though there are so many of them. Which is it? I don't view the loss of a Camry as being equivalent to the loss of a shuttle. That's nuts.

Again, another accident wll kill the program and NASA knows it.

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#19 2005-03-02 19:46:42

hubricide
Member
Registered: 2004-07-26
Posts: 49

Re: Running on Empty - NASA launches with a wing and a prayer

True, there are only a small number of shuttles, two out of 5 (ie not counting "Enterprise") of which (40%) have been lost. But that is not a "launch failure" of 40%! The Challenger, for instance, had 9 successful launches before it exploded in 1986. The Columbia had nearly 30.

Is this something to boast about?

Surely you are just seeking to stir up trouble..  The space shuttles FLY INTO SPACE on GIANT ROCKETS FULL OF HIGHLY EXPLOSIVE FUEL.  They orbit the Earth at 17,500 miles an hour.  They are SPACE SHIPS.  THEY GO INTO SPACE.  THEY MUST ESCAPE EARTH'S GRAVITATIONAL PULL.

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#20 2005-03-02 21:07:57

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

Surely you are just seeking to stir up trouble..  The space shuttles FLY INTO SPACE on GIANT ROCKETS FULL OF HIGHLY EXPLOSIVE FUEL.  They orbit the Earth at 17,500 miles an hour.  They are SPACE SHIPS.  THEY GO INTO SPACE.  THEY MUST ESCAPE EARTH'S GRAVITATIONAL PULL

There is no need to shout.

When the shuttle system was first pitched, they were promoted as very safe reusable vehicles having a vanishingly small chance of failure, perhaps one accident out of a thousand, or ten thousand missions. Whatever, the initial claims of safety were extravagant. The revised claims that followed were still extravagant.

When the Challenger was lost all of those claims went out the door. I remember, vividly, where I was when I heard about it. You might not be old enough. One loss grounded the program. Just one. You didn't ground it. I didn't ground it. NASA grounded it. We were shocked. We knew it was coming but were living in denial.

Now, there have been two failures and NASA has no choice but to take it seriously, again. The loss of two flight crews and two shuttles is not acceptable. A failure rate of 2% is not acceptable. It has nothing to do with what you say or I say.

I think NASA would agree with that as they are putting a lot of time, money and people's careers into making the shuttles safer than 2%. Two percent is not safe enough for NASA. Not me, not you, NASA is making that call. Get it?

You can factor in decades of time, planes and boats, bicycles, waxed floors, cat litter, anything you choose and it would not matter. 2% is not safe enough for NASA. They have established their own bottom line.

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#21 2005-03-02 22:07:57

hubricide
Member
Registered: 2004-07-26
Posts: 49

Re: Running on Empty - NASA launches with a wing and a prayer

Regardless of whether the space shuttle blows up zero more times or blows up a million more times, the US, and any other government, has to know that it would cancel its manned space program at its own peril.  Someone somewhere will have the guts to continually fly people into space, as safely as possible, yes, but regardless of just how safe it can be made, and those that continue to do so will be the ones who gain more benefits than those that don't.

If there is indeed another shuttle accident and NASA does indeed cancel manned flights altogether (forever?  I really can't see it happening), then the US will have lost a huge opportunity to learn and discover huge things about the universe in which we live.

The shuttles are of course more dangerous than 747s (go figure!) but they are not anywhere near the danger level necessary to prevent people from trying.

You seem to be saying that since occasionally people die we should just ditch the entire program altogether and sit on our hands here on Earth for the rest of our days.  That, frankly, is an insane viewpoint, tantamount to saying that we should never have left our caves or that we should all just hole ourselves up in our houses and never leave, because hey, you might get shot, or hit by a meteor, or you might get skin cancer in 80 years.  Hide on Earth if you want, but it would be a huge mistake for any sizeable amount of people to take your viewpoint.

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#22 2005-03-04 13:49:00

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

It's not my viewpoint, it's NASA's.

A word about safety. When SpaceShipOne made its successful second  landing, there was a brief press conference in the desert and all of the major players had their say. The first subject Rutan addressed was safety. It's safety first, he repeated that over and over. Keep it simple and keep it safe. Safe safe safe

And another thing, regarding the loss of shuttle crews. When people talk about the loss of a shuttle, the picture in their minds is that of the vehicle. The crews are an abstraction, they are unknown and are lost in the wake of the accident.

But those people were dear to each other. They trained together, drank beer together, had pizza together. They knew each other's families and birthdays. They made up softball teams with each other and had become good friends over the years. If you have never lost a family member unexpectedly, you don't know the meaning or the pain of sorrow.

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#23 2005-03-05 14:19:17

hubricide
Member
Registered: 2004-07-26
Posts: 49

Re: Running on Empty - NASA launches with a wing and a prayer

I agree that everything possible should be done to avoid unnecessary risk.  But everything in life has risk, and the adventures with the most possible benefit are always the ones with the highest amount of risk.  Blame God.  smile

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#24 2005-03-05 16:20:20

LtlPhysics
Member
From: north of the equator
Registered: 2004-02-24
Posts: 76

Re: Running on Empty - NASA launches with a wing and a prayer

If you give God the glory, you got to give God the blame.

If everything goes as planned, that is, the shuttles are returned to flight and the ISS is completed (ha), there will be a period of time where the US will not have a manned platform. NASA will retire the shuttle like a poor cousin and be happy to be rid of it. The US will have to book flights with the Russians. Life is good. More whiskey.

2004 was a banner year for NASA and perhaps we have all been spoiled. The rovers on Mars are in good health and will be run until their wheels fall off. Barring a catastrophe, Cassini is good for at least four years and probably longer if past experience holds sway. Other than that and some smaller cheaper designs, NASA doesn't seem to have any forward momentum. If handed an extra $10 billion, would they know what to do with it?

That new CEV vehicle, a mini-shuttle, what's that good for? Do we need it to get to the ISS, to the moon? If the ISS cannot be completed why build a ferry system designed, in part, to service it? For that we have Soyuz.

Heavy lift, do we have it? If we don't is it possible to do some crude, very, very crude assembly in LEO of medium lift pieces? Would that require a completed ISS or is the ISS just getting in the way? Are there spacecraft pieces that are designed to auto dock with each other? The Russians seem to have a basic docking system, if they have one why construct another?

Is China really interested in the ISS? Should we sell it to them? Perhaps we should give the keys to the ESA. Here, take it.

The shuttle's launch platform is probably as close to perfection as it will ever be. The solid fuel boosters are the most scrutinized boosters that have seen the light of day. The new external tank has a couple of heaters, among other improvements, and the amazing engines have not suffered a turbine loss (catastrophic). The shuttle c might not be quite heavy lift enough, but would two launches suffice? Could the two packages mate on their own and be on their way?

It makes no sense to maintain the shuttle's infrastructure but could part of it be used for the CEV, if and when?  Is anything salvageable besides the hangars?

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#25 2017-07-14 19:50:04

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 17,741

Re: Running on Empty - NASA launches with a wing and a prayer

This is the SR-71 gallery-1496845809-lockheed-sr-71-blackbird-1.jpg to which we are so familar with.

http://www.dailymail.co.uk/news/article … -hour.html

Shaun Barrett wrote:

Coincidentally, I just saw a reference to this new aircraft, being built as we speak at the Skunk Works:

hqdefault.jpg

Successor to the SR-71 'Blackbird' - previous holder of the speed record for a production aircraft - this new version is hypersonic.
It's designed to reach Mach 6.

(Of course, conspiracy theorists maintain that, if Skunk Works tells you they're about to release an aircraft capable of Mach 6, that means they've quietly moved on, long since, to something much more exotic. wink )

After Years of Silence, We Finally Know More About the SR-71 Blackbird's Successor

http://lockheedmartin.com/us/news/featu … sr-72.html

1400599103878.jpg

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