I've gotten a few comments on this post that I want to respond to on the front page. They're subjects that I've discussed before, but there are probably a lot of new readers here, since many of them presumably came via the link from he whose links must be followed and NRO.

Several people expressed comments along the lines below, but I'll just respond to this particular one, since it's pernicious, and I commented at some length on this right after Columbia was lost last year.

I take some offense at the idea that, since we're planning to replace the shuttle fleet anyway, we can send them up to do more dangerous missions because we don't need them for much longer. I'm sorry, but if the safety of the astronauts is in question, as you indicated, then we should not send them up. The shuttles may be expendable, but the humans are not.

I'm sorry that you take offense, but any other idea is irrational, despite your claim to be a science and math teacher. Read again what you wrote. You are saying that human life is infinitely precious, and that there is nothing that's worth its risk.

Now, it's debatable whether or not a Hubble repair is worth that particular risk, but the attitude expressed here will make the president's new human exploration plans moot, since we cannot guarantee the safety of astronauts who go to the moon, or even into low earth orbit, let alone Mars.

I know that this will sound politically incorrect, but the reality is the exact opposite of this reader's commentary. We have more astronauts than we know what to do with, but we only have three orbiters, and they are essentially irreplaceable, since most of the tooling for them and knowledge of how to build them is gone. It would take several years, and many billions of dollars to replace one, and it would be an extremely foolish expenditure. So the decision as to whether or not to save Hubble with a Shuttle has (or at least, should have) little to do with crew safety, and everything to do with whether or not we're willing to risk a third of the remaining fleet. In my opinion, it is worth it, if the odds are 98% success.

This is why the notion that we should send the Shuttle up without crew is senseless. The major asset at risk is the orbiter itself, and sending it up sans people (as another commenter suggested) does nothing except dramatically reduce the possibility that the mission will be successful, at very high cost. Hubble was designed to be serviced by astronauts, and that's the most reliable means for it to be serviced this time as well. If a telerobotic mission is successful (and I consider such a mission very high risk--a subject on which I'll be discoursing further in the coming days), it can be done without Shuttle, and an uncrewed Shuttle adds zero value to a Hubble repair mission.

Let's get this straight once and for all, folks. The primary purpose of sending an orbiter into space is to deliver astronauts into space--the other cargo capacity is just lagniappe. Unmanned orbiter missions are largely pointless, given their ridiculously high cost, yet the notion continues to surface, among both the public and people who should know better, like Congressmen.

This commenter below is entitled to his opinion that:

Hubble needs to be replaced, and not having a telescope in space for a couple of years isn't a big deal at all.

But his opinion is apparently not that of the space-interested public, or there wouldn't have been such a hue and cry when NASA made the decision. There's no question that Hubble needs to be replaced, but it's continuing to provide good science (and beautiful images) and given that we're going to be continuing to spend billions on the Shuttle program, money largely wasted, it would be nice to get a little value out of it for this mission to keep the system alive until it's replaced with something better.

Finally, as to this:

Your probability calculations tell me (I'm a math and science teacher, for the record) that you have fallen into the infamous "gambler's fallacy". Basically, the gambler's fallacy goes something like this: if I flip a coin, and it lands on heads, then the next time I flip the same coin, it is more likely to land on tails, since the coin should land on heads and tails in roughly even amounts. In fact, the probability on the second flip is still exactly 50/50. What you have said here is equivalent, though with a smaller probability. You seem to be claiming that, because the shuttle has a 98% (or so) success rate, and the remaining shuttles have made a large number of successful trips, that the probability of them being destroying is increasing with each successful mission. While this may be true from an engineering standpoint (since parts and materials degrade over time), you can not reach that conclusion by looking at straight probabilities.

I have no idea how he could so misinterpret what I wrote. I am claiming no such thing, and I don't know how I even "seem" to be claiming it. I repeat: "At that reliability, there is a forty percent chance of losing another orbiter (which would cost billions and years to replace) in the next twenty five flights. There's a two in three probability of losing one in the next fifty. That means there's an excellent chance of losing one over the next ten years, at an optimistic flight rate of five per year."

My claims are that if there is a two percent chance of loss per mission:

• There is a two percent chance of losing the Hubble mission, which is, after all, a...mission
  
• There is a forty percent chance of losing an orbiter and crew in the next twenty five flights
  
• There is a sixty seven percent chance of losing one in the next fifty flights
  

With which of these statements does our math and science teacher disagree? Which of these statements represents the gambler's fallacy, or says anything about extrapolating the probability of the success of the next flight from past performance?

You still haven't answered either of my questions. First, is Hubble valuable? The response to my last post went:

Also, I've heard from some amateur astronomers that there are now many land based telescopes that give equally good pictures as Hubble.

This is getting more common as time goes on. BUT 1) they can't do this in all regions of the sky and 2) they can't do it at all wavelengths.

Also, there is the prospect of replacing Hubble in the next few years:

it would be nice to get a little value out of it for this mission to keep the system alive until it's replaced with something better.

So what your saying is that we need to put billions of dollars, seven human lives, the reputation of NASA, and the future of the space program at a nominal 2% risk to gain a marginal benefit (that is greater wavelength access and certain areas of the sky for a few years). Maybe we should, but I think more analysis needs to be done than what we have here.

Second, the new mission of NASA is manned space flight to the Moon and Mars. This mission is going to eat up a majority of NASA's budget for the foreseeable future. If Hubble doesn't support that mission, how can it's enormous recurring costs be justified? They can't.

Also, I would like to mention that (I imagine) that Sean O'Keefe has already looked at all the costs and benefits of Hubble and found it wanting. The sentimentality of the "space-interested public" notwithstanding, Hubble just isn't worth it.

If the question is whether to put 7 human lives and an irreplaceable Shuttle to small (but real) risk to get marginal benefit out of Hubble, the answer is simple: Gads yes!

Hubble has been extremely valuable in unlocking the secrets of deep space and pushing physicists in new directions. But it's been much much more valuable in keeping the minds of our current scientists and the next generation in wonder. Hubble's shown millions of children what the stars look like far beyond what their eyes can see from home, and it will pay off as those children take some of that wonder and put it into their lives growing up. Whether they all become scientists or not, future society will be better off for that. Call it an intangible benefit, but it's not easily dismissed. To wave this off as sentimentality is to miss the point of exactly what sentimentality means to us as a people.

Yes, we still need Hubble up there, both for the science it produces and the human spirit it stimulates. Was the first moon shot any different? I'd argue that's very worth the risk of 7 lives, and I'd bet they would too--after all, they took the initiative to push to join the program and face that risk, for missions far less glamorous. If Hubble is to die, let its successor be in the sky with it by then.

Again we see that our education system does no teaching of just what risks mean and how to assess them. If the concern is human life, do you play russian roulette with two rounds in the revolver (comparable to the 40% chance over 25 flights) or dine twice on puffer fish (which, if I recall right, is something in the vacinity of a 2% chance of dying). So the logical thing to give up on is Space Station, not Hubble.

- Eric.

If Hubble doesn't support that mission, how can it's enormous recurring costs be justified?

The major costs:
The shuttle itself: One shuttle flight (at $70-$100 a flight - remember you are already flying the shuttle for ISS so you can write off the high fixed costs of STS with respect to HST) every three years.

New instruments - Some are already built and paid for (e. g. WFPC3 and COS). Others might be competitively bid for as individual Discovery-class missions.

STScl - The Hubble control center will be running the Webb Space Telescope, so you will not save money by shutting that down.

The plan Bruce McCandless proposed in 2003 for SM-5 (using a standard shuttle-based service mission to practice precision telerobotic techniques - with astronauts onsite to lower risk to Hubble) would directly bear on the human-robotic aspect of the new Vision.

So the costs of continuing shuttle missions to Hubble are on the order of $100-$200 billion over the next decade. No replacement high resolution UV observatories have even been proposed that I know of. Webb (even if it deploys successfully) fails to duplicate most of Hubble's capacities. I suspect that aesthetically images from HST will remain superior to those from WST (due to resolution and wavelengths).

So there is a very good case for continuing service missions. I suspect it will require a new Administrator for the policy to change. Yet another reason to fire Rumsfeld - give O'Keefe a promotion?

So the costs of continuing shuttle missions to Hubble are on the order of $100-$200 billion over the next decade

Bah, $200 million. Sorry.

at $70-$100 a flight

Bah - if only.. $70-$100 million per flight...

Today is not the day to balance my checkbook...

Don't worry, Duncan, once you start throwing all those "illion" numbers around, it's all the same to me...

Today is not the day to balance my checkbook...

Unless you're Bill Gates--then you could afford the error.

As for replacing O'Keefe, it's not clear who might replace him that would be an improvement. I'm eagerly awaiting the results of the Aldridge Commission to see if a) they come up with any fresh approaches and b) to see if the administration follows through and implements them .

As for the first commenter ("I'm sorry, but if the safety of the astronauts is in question..."), I'd say that the astronauts themselves would take offense at that attitude. They're mature, rational adults, they know what the risks are in a Hubble repair mission (or an ISS mission, or any other space mission), and they're willing to take those risks. In short, they knew the job was dangerous when they took it.

If Americans as a society are willing to let thousands of soldiers risk their lives in Iraq and Afganistan doing a job that needs to be done, then perhaps they can let six or seven astronauts risk their lives on a Hubble repair mission (another job that needs to be done, IMO).

Your comment about surplus astronauts remind me of a comment made by amid-levle NASA administrator at a meeting at MSC in the mid-sixtes when an astrounaut complained that a proposal would be dangerous to astronauts. The adminstrator said "Ve got lots of astronauts".

I like the idea of having a reusable robot tug move Hubble to ISS. It would be useful for many things beyond Hubble. If it is feasible, it would be a win-win situation.

While I don't have a problem sending a Shuttle to save Hubble, I can understand that the logistics with the new flight restrictions would make it very difficult to do that and ISS service flights too. And the Shuttles are getting older, so the chance of failure is probably increasing.

Mike, I take great exception to this:

"Second, the new mission of NASA is manned space flight to the Moon and Mars. This mission is going to eat up a majority of NASA's budget for the foreseeable future. If Hubble doesn't support that mission, how can it's enormous recurring costs be justified? They can't."

I'm one of the biggest supporters of manned space you are going to find, but I am also a big supporter of Hubble. It is one of the most powerful tools of exploration the human race has ever created, and is doing things manned flight cannot. Also, the cost to keep it going is tiny compared to the manned space budget. If money is not to be spent to save Hubble, I would prefer an equal amount be spent to accelerate new space telescopes that have far greater resolution and light gathering capability. I want to see the planets around other suns.

"Second, the new mission of NASA is manned space flight to the Moon and Mars."

Well, no. That's the 'sound bite' version the media is reporting. The reality is quite different. A better description of the change in NASA would be, "NASA is moving from exploitation to exploration." That exploration includes manned AND unmanned missions. Projects like the Terrestrial Planet Finder, the James Webb space telescope, and the Jupiter Icy Moons orbiter are all part of the new Exploration Systems division within NASA. None of these projects are getting funding cuts, and in fact I expect to see funding increases for robotic exploration as part of the new vision.

Also, the moon is not just a 'stepping stone to Mars'. That's another distortion of the new vision. The new vision, with respect to manned space flight, is this: Build a comprehensive, extendable capability for exploring space. Start by building a modular spacecraft that is suitable for missions to the moon, Mars, the asteroids, Lagrange points, etc. Develop new techniques for inhabiting other worlds. Go to the moon first and shake it all out. Improve the technology, shake the bugs out of the hardware, learn from the mistakes, and get to the point where you have a robust, sustainable capability. Then expand the envelope to other locations. Maybe Mars is the next likely candidate. Or perhaps an Asteroid. Perhaps somewhere else. But do it incrementally and sustainably."

I like that approach. The 'Mars Direct' plan is more akin to Apollo - a one-shot 'flags and footprints' mission that, once over, doesn't really leave your space capability much better. If we're serious about going into space, we need to avoid stunts and one-shot missions, and start serious work on the hardware required to let us go where we want, when we want.