You are not logged in.
I think spacerep was just having some fun, planting a picture of Star Trek's Data at the head of the article.
At some point uncertainty will be a factor as to how small components can be.
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.
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.
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.
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?
I will admit that there is a bit of devil's advocacy going on here, but regardless, another loss and the party's over.
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.
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.
Colonizing Mars and colonizing the asteroid belt are not equivalent ventures. What kind of life would families have scattered about, limping from rock to rock in the asteroid belt? Humans are gregarious animals and they suffer when segregated from their own kind. I can't imagine an active human presence among the asteroids, save for a few cowboys. Colonizing Mars, on the other hand, is not nearly as bleak.
As an aside, by the time Earth is in dire need of the resources that can be found in the asteroid belt, we will have developed robotic systems that can sample a rock, chart a course and deliver a given load to a given location. The journey will probably take a few years, but the children won't miss their adolescence.
As a second aside, by the 22nd century the solar system will probably have robots near everywhere.
That's the smart way. No crazy trips to asteroids. No massive expenditures that ruin our childrens future. And no star trek warp drive needed.
The future Earth would have to be desperate in the extreme for whatever resources the asteroid belt has to offer. The future Moon and Mars, just a little less desperate.
Mining the asteroids to terraform Mars, itself a lofty notion, will be a task suited to begin in the 22nd century, more or less, and the incentive to do so would have to dwarf the incentive not to bother. The expense of the infrastructure is staggering.
But, there might be a few cowboy types that wouldn't mind life in a can and could sail a prime asteroid into Mars orbit, or shove it directly into the planet. That might happen, after Mars has been fully documented by the sciences and is desperate for metals and ice.
But, again, given enough robots and propulsion devices, Mars could eventually have a litany of mini-moons without too many cowboys on the payroll.
That said, 'colonizing' the asteroids is science fiction.
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.
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.
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.
China and Russia will be having war games to better coordinate each other for the war on terrorism? That's a hoot.
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?
I remember those Soviet probes. One of them that made it to the surface used a low-tech approach to keep the spacecraft working once it reached the ground. They spent some time exposing the entire lander to the vacuum of space, letting the probe get as cold as possible before entry.
Mars clearly has a wisp of an atmosphere, but I didn't figure it was appreciable enough to scatter blue light (or block nasty radiation).
What would the sky of Venus look like?
Does this mean that every planet with an appreciable atmosphere always scatters radiation that is at least as energetic as blue light?
If we are going to get Lunar fuel in on this... why not just put the telescopes there and use nuclear energy?
That's the best of all possible scenarios.
"...build a tug that could nudge the original telescope to a safe haven and have something to show for it when it's over. A useful tug, perhaps the first of many instead of a one shot doomsday machine. Even if it fails, the engineers will have been thinking in the right direction, one of creation rather than destruction."
Nope, because if you don't save Hubble before its batteries fail, then the whole telescope is worthless. Why? If Hubble loses power, it can no longer keep its electronics warm in the cold of space, and they will be quickly ruined. Pushing Hubble into a higher orbit for some future service mission isn't going to happen.
It's a given that Hubble will be scientifically useless way before 2013, whatever its location. It will never be refurbished The idea of building a tug isn't so much about the Hubble as it is about the tug.
Now it could be your position that a tug is a boat with no clear mission, other than the experience of its construction, which is much like the ISS. What would the tug tug? If the current trend is one of expendables, why bother designing tugs?
Simple crude assembly of future probes, perhaps, although the notion of complex constructions in orbit is way oversold.
Time out.
I found this on AP -
Updated: 11:42 AM EST
Is Hubble Telescope Worth Saving?
By DEVLIN BARRETT, AP
The chairman of the House Science Committee said Congress needs to decide whether the 14-year old telescope, renowned for its inspiring snapshots, is worth the cost of repair - estimated to be as much as $2 billion.
''We have to make hard choices about whether a Hubble mission is worth it now, when moving ahead is likely to have an adverse impact on other programs, including quite possibly other programs in astronomy,'' said Rep. Sherwood Boehlert, R-N.Y.
Hubble hovers about 375 miles above the Earth, circling the planet every 95 minutes, and has seen galaxies that are more than 12 billion light years away.
While NASA has sent several repair missions, experts say an additional one is needed because the batteries and gyroscopes probably will fail between mid-2007 and 2010.
But with the crash on Feb. 1, 2003, of the space shuttle Columbia, a manned mission to repair Hubble is not worth the risk, said Rep. Dana Rohrabacher, R-Calif.
''Some people just want to dive back in and use the shuttle as if these catastrophic accidents didn't happen. ... To the degree that we don't have to use the shuttle, we shouldn't use the shuttle,'' he said.
Experts also are divided about the best course of action.
NASA caused an uproar among scientists last year when the agency said that the safety of astronauts should not be put at risk in order to repair Hubble.
A National Academy of Sciences committee concluded in December that NASA should use astronauts, not a robot, for a repair attempt.
''The crew risk of a single shuttle mission to Hubble is very small,'' the chairman of that committee, Louis Lanzerotti, a professor at the New Jersey Institute of Technology, told lawmakers Wednesday.
But Dr. Paul Cooper, an executive at the company asked by NASA to create a Hubble-repairing robot, said such a trip could be of huge scientific benefit in future repairs of U.S. satellites, particularly for the Defense Department.
The goal of any repair mission to Hubble would be to install fresh batteries, gyroscopes, fine-guidance sensors, and two powerful new cameras that could make the telescope more productive than ever.
NASA has agreed that failing all else, it will use a robotic spacecraft to steer Hubble into the ocean by 2013.
-------------
So, that's the bottom line. The Hubble will be scientifically useless but still stable enough so that an assassin spacecraft can attach itself and dispatch Hubble into the deep.
So, what are we left with? Hopefully a Hubble II will have had a few years of observations under its belt, but the mission to scuttle the first Hubble is an expense with nothing to show for it. Nothing of any value was created. I've heard estimates of $300 million to create the de-orbit spacecraft and maybe that's about right, maybe not. Whatever it costs, it's money gone.
But, we have the luxury of 8 more years to mull it about. I would use the intervening time and budget, maybe more, maybe less, to build a tug that could nudge the original telescope to a safe haven and have something to show for it when it's over. A useful tug, perhaps the first of many instead of a one shot doomsday machine. Even if it fails, the engineers will have been thinking in the right direction, one of creation rather than destruction.
Hitting the LaGrange point is just a matter of physics, its pretty easy. Just make sure that the english/metric conversions are done correctly.
Ed Weiller tried to take the heat off NASA by commenting, to paraphrase, "Mars still has surprises for us," as if the metric/english fiasco was somehow the fault of Mars, and not human error.
What was NASA's experience with those poky Deep Space probes?
The Hubble buzz reminds me of the Balkans. Everyone living there had their own map of the place.
http://www.space.com/adastra/adastra_hu … 50128.html
That proposal would require the creation of a tug, a vehicle the Earth needs anyway. Who knows where that might lead?