Might Shuttle C - save Hubble?

GCNRevenger · 2004-07-19 15:09:40

NASA is making noises about looking for a compromise on the day-launch only issue by employing additional spotter aircraft with IR/NV cameras.

BWhite · 2004-07-19 15:34:28

Hmmm. . .

I am being persuaded that STS can finish ISS by 2010. Crews of 2 or 3 help that greatly, IMHO.

But okay lets say it does.

President Bush has already left office. The orbiter has worked flawlessly between 2005 and 2010. As GCNRevenger has said himself, without orbiter ISS has essentially no use or purpose.

(Albeit with only a little use or purpose with STS)

NASA comes to the next President in 2010 and says, STS has been working flawlessly and if we keep using it we can do so much more. . .

clark · 2004-07-19 15:40:42

NASA comes to the next President in 2010 and says, STS has been working flawlessly and if we keep using it we can do so much more. . .

*Bzzz* Sorry Chuck, incorrect response. We were looking for, "what is CEV."

Come 2010, first block CEV is being produced for a fly off. We need human rated lift. After ISS is built, we don't need Shuttle because we have ATV cargo, and the only discernable justification for Shuttle is to return science racks... which I'm sure we cane either discontinue in lieu of human-microgravity research and/or alternative return options.

Boeing CEv designs call for a return-to-earth capability for a cargo module.

Another 6 years, and we are looking at recertification and billions more to keep those same three orbiters flying. It's just not worth it (we have to find something more for them to do by the way). CEV will be a cheaper alternative.

BWhite · 2004-07-19 15:49:17

Okay, suppose Boeing donates to the wrong candidate.

= = =

Has anybody asked the ISS partners whether they might prefer to joint venture on http://www.space.com/news/igy_space_040719.html]this and just forget about ISS altogether?

We can't break an agreement all parties agree to cancel.

= = =

CEV ain't nothing but a view graph. . .

GCNRevenger · 2004-07-19 16:59:03

The fact of the matter is, that as long as Shuttle flies and the US is pouring so many billions into the ISS, that there will be no activity outside of Earth orbit... ever. Shuttle costs ~$4.0-4.5Bn per year, every year to fly and the ISS a few more on top of that... All manned-related activities cost around $7-10Bn a year more or less. There just isn't any money to do anything but send probes for this kind of money, not MarsDirect, not Apollo-II, not anything. Its either the Shuttle and ISS goes, or NASA stays put in LEO.

Unfortunatly for the ISS, even with the ESA's ATV, there still isn't much to be done up there without Shuttle. Science racks won't fit through the door that the station is built around... There isn't going to be a HAB module, which limits the crew to 3 even if you do have CRVs enough... The Europeans aren't building fleets of the expensive ATV's either, nor can Progress deliver much payload. Don't forget that Progress and ATV share the same kind of port... And most of all, the physical condition of the ISS is not that good, and without Shuttle to deliver big, heavy replacement parts on a regular basis, then ISS isn't going to last much past 2010 anyway. It simply took too long to bulid.

RobS · 2004-07-19 21:17:30

Regarding Hubble, there was a third option mentioned in the Houston Chronicle a few weeks ago that needs to be considered seriously: build a solar-powered electric propulsion vehicle (a solar ion tug) for a few hundred million, launch it with an EELV, and use the tug to move Hubble to ISS. The plane change is energetic, but possible with a solar-ion tug. At ISS (or ten miles from ISS) the shuttle can do a standard Hubble repair mission and still have the ISS as a lifeboat. Then the tug puts Hubble back into its design orbit, or any other orbit one desires.

Furthermore, the solar ion tug would be a prototype for something that could move satellites cheaply to geosynchronous orbit or cargo to lagrange. A solar ion tug could even do a plane change on ISS while maintaining its orbit against atmospheric drag.

And such a vehicle could be designed and built for less than a billion. The estimates are usually half a billion, I think.

-- RobS

GraemeSkinner · 2004-07-20 00:10:23

If they could make a solar-ion tug that was re-usable perhaps it could be made to dock with the ISS for future repair missions. We are getting more and more satellites in orbit, not all of them achieve correct orbit, or even work once they are out there. Why not have a tug that can go out, retrieve the defective satellite (or whatever) and take it back towards the ISS for repairs, or if the sat. was in the wrong orbit it could drag to it to the correct one. And what about space-junk? Could an solar-ion tug be used to capture these items (the large ones anyway) and drag them to a point near the ISS where a simple booster could be fitted and fire them out of orbit reducing the amount of clutter thats building up out there.
I don't know a lot about ion propulsion, so I don't know whats possible with them and what isn't.
On the subject of a robotic repair of Hubble, the cost would be very high, but it would also give us a chance to experiment in sending a robotic repair system into space - something that could prove quite useful in future. Would it not be more beneficial to try something now whatever the cost rather than wait until we absolutely have to send one not knowing what problems we're going to encounter. Like the solar-ion tug, why not make it re-usable, with some sort of propulsion, when its done with Hubble send it on to the ISS for storage and refit as required for future repair missions.
Either system (ion tug/robotic repair) would give us a chance to experiment, letting Hubbles orbit decay would achieve nothing other than wasting money and equipment.

Graeme

RobertDyck · 2004-07-20 03:26:13

There are a lot of good ideas to service Hubble. They all could work. However, the idea of replacing it will not happen. If a billion dollar national asset is considered just a piece of junk to be thrown away, then why would congress waste the same amount of money again? That would be just throwing good money after bad. A billion dollars is not nothing. The only way any space telescope will get support is if it's treated as an asset, not a chewing gum wrapper that's thrown away. Retaining a valuable asset means maintaining it. I'm sure the robotic service mission will cost millions, but not a billion. A tug to move Hubble to ISS is another good alternative. We have to start thinking of spacecraft as vehicles, not ammunition. The military doesn't think rockets or anything on them can be reused because they think of an ICBM, ammunition. You don't get ammunition back. But any manned spacecraft, whether it's Soyuz or Apollo or CEV, or even an unmanned tug, is far more complicated and expensive than a warhead on an ICBM. What is the cost of a spacecraft vs. the expendable launch vehicle? A true spaceplane may require further research, but a reusable spacecraft atop an expendable launch vehicle is possible now. A reusable on-orbit tug is also possible. Servicing Hubble has already been done several times, now it's just a matter of getting congress over its jitters. When it comes to space, they have always turned a blind eye to the danger then demonstrated their glass jaw with every setback. Engineers told NASA that Challenger couldn't be launched when it's that cold, but they did anyway. The first Shuttle flight lost heatshield tiles, the tiles were inspected from the ground with a military telescope, but no facility was given to NASA to inspect on its own. Now, 24 years after the first Shuttle flight, it's getting an inspection system. But as usual, congress overreacts. They don't want to simply do what should have been done 24 years ago and continue on, they want to claim Shuttle is fundamentally unsafe. In the process they're abandoning Hubble, a billion dollar asset. Reality is that if proper precautions are taken, don't launch when it's too cold for the SRBs and take along a heat shield inspection system, a direct Shuttle mission to service Hubble can be justified.

Palomar · 2004-07-20 06:32:09

There are a lot of good ideas to service Hubble. The all could work. However, the idea of replacing it will not happen. If a billion dollar national asset is considered just a piece of junk to be thrown away, then why would congress waste the same amount of money again? That would be just throwing good money after bad. A billion dollars is not nothing. The only way any space telescope will get support is if it's treated as an asset, not a chewing gum wrapper that's thrown away. Retaining a valuable asset means maintaining it. I'm sure the robotic service mission will cost millions, but not a billion. A tug to move Hubble to ISS is another good alternative. We have to start thinking of spacecraft as vehicles, not ammunition. The military doesn't think rockets or anything on them can be reused because they think of an ICBM, ammunition. You don't get ammunition back. But any manned spacecraft, whether it's Soyuz or Apollo or CEV, or even a unmanned tug, is far more complicated and expensive than a warhead on an ICBM. What is the cost of a spacecraft vs. the expendable launch vehicle? A true spaceplane may require further research, but a reusable spacecraft atop an expendable launch vehicle is possible now. A reusable on-orbit tug is also possible. Servicing Hubble has already been done several times, not it's just a matter of getting congress over its jitters. When it comes to space, they have always turned a blind eye to the danger then demonstrated their glass jaw with every setback. Engineers told NASA that Shuttle couldn't be launched when it's that cold, but they did anyway. The first Shuttle flight lost heatshield tiles, the tiles were inspected from the ground with a military telescope, but no facility was given to NASA to inspect on its own. Now, 24 years after the first Shuttle flight, it's getting an inspection system. But as usual, congress overreacts. They don't want to simply do what should have been done 24 years ago and continue on, they want to claim Shuttle is fundamentally unsafe. In the process they're abandoning Hubble, a billion dollar asset. Reality is that if proper precautions are taken, don't launch when it's too cold for the SRBs and take along a heat shield inspection system, a direct Shuttle mission to service Hubble can be justified.

*I agree with you completely on this, Robert.

Unfortunately a few people seem not "to get" what you are saying (as per similar past posts of yours, which seem to be somewhat ignored). Oh well. :-\ You're certainly more knowledgeable and logical than some prattling wannabe know-it-alls I can think of.

Anyway, your posts are "spot-on" IMO.

--Cindy

GCNRevenger · 2004-07-20 08:47:17

There are alot of options for repairing Hubble... they could work... they could not... but all of them have one thing in common: They cost hundreds of millions of dollars. The robot repair vehicle that everybody is hailing is right now shaping up around $750M. Yes, actually, it could very well cost One Billion Dollars. You could afford to build a whole new telescope for that much which would last years longer. Or for a tenth of that money, you could build a super-telescope on Earth, sterioscopic vision, more light gathering power, and now adaptive optics which correct for atmospheric fuzziness... which Hubble was intended to circumvent all along.

So, how much is HST and "experience with space operations!" worth?

Building a solar-ion tug, or even a plain old chemical one sounds kinda good. "Build infrastructure" and whatnot. Well, the question begs... why? To fix broken satelites? The vast majority of them DO work, and that percentage is getting better every year. And now, since they really are being mass-produced, it makes no sense to mount a "rescue mission," just launch a spare. Rescue missions are expensive, each HST repair was a billion-plus dollar affair, and you won't have convienant spare satelite parts on orbit, nor will the the satelites be built for easy orbital handling! And how much longer do you think the ISS will be around for, anyway? You certainly wouldnt suggest sending humans out to risk fixing a broken satelite. That is, if it hasn't torn apart or spun out of control or reenterd still bolted to the GTO stage.

And why do you need a tug? Why really? There are so few failed satelite launches where all it needs is orbital correction, and now they are sporting' ion engines of their own (see Boeing 701 series). Why then would you need one? To connect pieces launched for Lunar missions? Whats wrong with the Russian method of having the pieces dock themselves, all you need is one payload launch that can maneuver and one TLI rocket stage or fuel tank.

Yes yes I know I know, it is counter-intuitive to throw it all away, but look and see... a reuseable rocket will cost billions and billions of dollars to develop, a small rocket like the DC-I would have cost nearly $10 billion, and a true TSTO Shuttle would have cost $20-25Bn... The EELV program cost one billion of USAF money, and each launch for similar payload costs $100M and $200M-250M respectivly.

That seems like a terrible deal, but really, how many launches will be needing? How many? There are only small number of satelite launches, and they are launched mostly by Delta-II and Zenit-III, perhaps pretty soon by Falcon-V... A Lunar mission will probobly not take more than four launches. Perhaps six. And thats about it.

And the money is scarse... there isn't enough to build a large RLV and go to Mars. There isn't enough money to build and operate a substantial RLV and go to Mars... Speaking of large rockets, that is another thing, that RLVs cannot launch large objects because of its low mass margin. Building large spacecraft out of small pieces is utter folley, if for no other reason than the fuel tank weight and orbital assembly... Look, look at Saturn-IV and Saturn-V, look at SDV's like Ares, or even an Atlas-VI... money going to an RLV is not going to these.

GraemeSkinner · 2004-07-20 09:51:11

So, how much is HST and "experience with space operations!" worth?

You can't IMO put a real value on HST, or on space operations experience. Well ok, accountants can put a value on them but they have to

In a very real way we are still on our baby steps with regards to space exploration; but rather than re-invent the wheel every time why not build on what we have. Hubble will be expensive to repair, there is no getting round it, but sending a robotic mission to carry out repairs and upgrades will not only extend its lifespan but give us experience in doing it. There can be no subtitute for experience, I'd much rather money was spent in learning to repair Hubble by remote than risk a manned mission.

Put it another way, you have a car thats in need of repair, do you spend the money on repairing it or throw it away and spend more than the repairs would have cost on replacing it - I know the maths are just a bit different in terms of space, but then costs are always astronomical in space exploration

I'm biased on the subject I'll admit, but IMO Hubble is still an excellent piece of engineering (as I'm biased I can turn a blind eye to its faults). If someone is not a fan (terrible term but I'll use it anyway), or does not see the value of keeping Hubble in orbit working, then whatever price is put on a repair mission will be too high.

Graeme

GraemeSkinner · 2004-07-20 09:55:23

.... Or for a tenth of that money, you could build a super-telescope on Earth, sterioscopic vision, more light gathering power, and now adaptive optics which correct for atmospheric fuzziness... which Hubble was intended to circumvent all along.

If plans to repair Hubble are thrown out of the window, I'd opt for this one. I'm just waiting for the price of adaptive optics to come down to amateur levels :;): then I'd be a very happy bunny.

Graeme

clark · 2004-07-20 10:09:20

However, the idea of replacing it will not happen. If a billion dollar national asset is considered just a piece of junk to be thrown away, then why would congress waste the same amount of money again?

Sometimes the cost of fixing a car exceeds the value of the car itself. Sometimes you are better off just buying a new one.

If the Hubble does have value, if it still serves a need that is a "must have", then a new one will be created. There would be a justification to do so.

I do not believe that the value of Hubble is worth risking the lives of astronauts, and one of our last three remaining Shuttles, to extend it's life for a few more years.

We need to get away from using the Shuttle. We need to move on. Keeping the Hubble will only serve to prolong our use and need of the Shuttle. It's just not worth it.

Let's figure out an alternative to the Shuttle so that if it does work, we can use this alternative in future years to prolong it further (if possible, and if warranted). Or, let's just build a new one and design it so that it dosen't need Shuttle repair missions. Times have changed, our directions have changed. Let's stop looking backwards.

Palomar · 2004-07-20 10:28:34

*Construction began on Hubble in 1977.

It was placed into orbit 13 years later, in 1990. Initial difficulties with out-of-focus pics prompted repairs; 3-1/2 years later the problem was fixed.

So, 16 years all in all, from beginning of construction to the first quality photos and data returning.

I doubt professional astronomers want to wait another 10 to 16 years to see a new Hubble build and put into orbit (::edit:: especially since we've already got the goods up there, with consistently marvelous returns and good workability ::end edit::). Nearly 2,000 professional astronomers applauded the decision to send a robotic mission at a recent conference. That can't be a coincidence.

Also, is it conceivable that any long-term telescope can be built to -not- require repairs of some sort? If no, and even if shuttle-oriented missions can be bypassed or eliminated to perform occasional repairs/upgrades, then it's got to be accomplished somehow. Most likely via robot repair. So why not begin robot repair NOW?

--Cindy

P.S.: Graeme, I agree with your reasoning.

::EDIT:: Wanted to add that I don't believe in sacrificing discovery and science -- or allowing it to be interrupted for years on end -- when a relatively affordable and easy solution to PREVENT interruption of incoming data can be accomplished.

There...off my soapbox.

RobertDyck · 2004-07-20 10:36:52

First, I don't believe you when you claim ground-based telescopes are as good as Hubble. Ground-based telescopes are getting better, but they still don't come close to the resolution of Hubble. Hubble is not about "experience with space operations", it's about imaging celestial objects that bring much more science information than we have ever had before.

Part of the problem with the North American culture is the "throw away" mentality. Cars are driven for a few years then thrown away. Car shows demonstrate that a properly maintained car can last half a century. However, car manufacturers don't want owners to keep their cars for a decade or two, so replacement parts are sold in large assemblies that require replacing large and expensive portions. Service stations used to sending parts out for refurbishment, or replace parts with rebuilt ones and give a "core" value for the old one. They aren't doing that any more because it's more profitable to throw away, read "price gouging". Cars are often designed with built-in obsolescence; they are designed to only work until the warranty runs out then fall apart. They don't have to be that way; cars have been built with polymer body panels, stainless steel chassis, aluminium alloy suspension, etc. Now you want to apply the "throw away" culture to billion dollar space assets!?

A tug has many uses. Assembling ISS modules without Shuttle is just one. Moving Hubble or other space assets around is another. Do you remember Space Station Freedom? That was designed with only one module that wasn't U.S. built: a Canadian satellite repair module. When Freedom as cancelled, Prime Minister Jean Chrétien cancelled the repair module. That would have required a tug to bring satellites to the space station, and return them to their operational orbit. If you want to use space resources, you will need a tug to bring the resources to satellites: fuel, solar panels, or whatever replacement parts you can make in space. Installing anything more than a fuel refill will probably require moving the satellite to a repair station.

Bottom line is: stop treating Hubble as valueless.

clark · 2004-07-20 10:43:32

Bottom line, stop treating Hubble as the end all be all of space exploration.

You want artificaly colored pictures of the vast cosmos, fine. I want red sand.

Hubble will not give me what I want. It stands in the way.

RobertDyck · 2004-07-20 10:58:57

Aaaaaaaaaaaaah! You see Hubble is in the way of manned exploration of Mars. That's what this is all about. Well, I don't see them as competing. We need human presence in space, and servicing Hubble provides that. We need successful science.

We need to build upon what we have already accomplished. If you just throw away everything you have and spend your money re-buying it, you'll never have money to buy something new. For one thing, we have to demonstrate to congress that space assets are not multi-billion dollar gum wrappers. We have to prove that assets can be retained and built upon. We have to prove that a program that takes multiple years to complete can be done. If you're space assets are thrown away after just a few years, then how do you ever expect to complete a program that takes 10-20 years? If the space hardware from the first years cannot last to the end of the program, then the program can never succeed. Mars Direct shows how a single mission can take 26 months, but COLONIZATION will take decades.

As for cost, what is the incremental cost of a single Shuttle mission? Ignore the overhead cost; that will be incurred as long as ISS is under construction. The only cost saving of not servicing Hubble is the incremental cost of a single Shuttle mission. Is the HST hardware already built? The cost per Shuttle launch may be over $500 million if you amortize the overhead cost over 6 launches per year, but the cost for an additional Shuttle launch in a year is around $126 million (twice the 1988 incremental cost of $63 million).

Palomar · 2004-07-20 10:59:31

*I get the feeling someone here would be defending saving Hubble left and right if nearly everyone else were opposed to keeping it afloat. :laugh:

Supposedly saving Hubble will prevent/hinder us from going to Mars (it's the old "either/or" silly debate tactic again) -- and yet the same person calls for a *new* Hubble to be built (which will cost even more $).

Yeah, that makes sense.

Hubble isn't a threat to Mars exploration/colonization. Tired old tactic, try a new one sport.

Oh, and about a mega-ground-based 'scope: Weather? Atmospheric disturbances? Hubble doesn't have to deal with that. Solar weather, yes -- but Hubble has withstood those all magnificently.

--Cindy

clark · 2004-07-20 11:07:41

Cindy, you seem to want my attention, so here it is: get bent.

If you're space assets are thrown away after just a few years, then how do you ever expect to complete a program that takes 10-20 years?

Hubble was a first ever, one of a kind. A proto-type if you will. I fail to see why building another one, with what we have learned, will somehow cost more.

The Hubble has been working for over a decade, and it's value diminishes with every advance. We have future telescopes we could be developing that will push the limit of our technology, and provide even more opportunites beyond what Hubble can provide.

As for cost, what is the incremental cost of a single Shuttle mission? Ignore the overhead cost; that will be incurred as long as ISS is under construction. The only cost saving of not servicing Hubble is the incremental cost of a single Shuttle mission. Is the HST hardware already built? The cost per Shuttle launch may be over $500 million if you amortize the overhead cost over 6 launches per year, but the cost for an additional Shuttle launch in a year is around $126 million (twice the 1988 incremental cost of $63 million).

We end up risking one of our three remaining orbiters and the lives of several astronauts. We need those Shuttles to finish ISS. That is a priority. By using a Shuttle mission to Hubble, we have to plan for worst case scenerio- so we take the Shuttle on a mission that is not a priorty adn create the opportunity of a serious situation where we have to save those astronauts- we end up creating a problem we could avoid by not using the Shuttle.

Shuttle should not be used. Hubble isn't worth it.

GCNRevenger · 2004-07-20 15:11:35

Cost of the robot mission: $750M. Perhaps more. No guarantee of sucess as this is an untried, risky operation. No guarantee Hubble will be save-able in time (loss of attitude control & spinning). HST remaining lifespan will probobly be less than for a new UV/Optical telescope.

Cost of the original HST, including launch on Shuttle: $3.0-3.5Bn (depending on who you ask).

Cost of the Spitzer SIRTF, including launch on Delta 7000 (NASA specialty Delta-II): $450M

...So, if we are so in love with UV/Optical space telescopes, then we take that billion dollars headed to the HST servicing mission and spend it on Hubble-II instead. Launch on EELV or Delta-7000, smaller and lighter.. collapseable shroud, liquid neon regenerative optics cooling, smaller rigid solar GaAs solar cells, long life metal hydride batteries, modern computers/communications (FlashROM not tapes), and of course a built-in deorbit rocket. No money spent to make it space-serviceable, weld the thing shut. Use the new cameras destined for Hubble, saving money... even take public donations. $1Bn is not unattainable for useful aperature size, just increase the exposure time.

A Shuttle mission would be no more expensive. It would probobly be cheaper. But NASA needs every single flight to finish the ISS by the 2010 deadline, and with no ISS as a shelter, an unfixable TPS failure would doom the astronauts going to Hubble... Its just not worth it and is not going to happen without Congress making a huge fuss. And again, Hubble won't last as long as a new scope', nor is there any promise Hubble will be capturable by launch time.

So... a risky chance to fix the old telescope maybe, or build a brand new one with the same cameras which will last for years long and have a better chance of working... for about the same money.

Oh and time for a little update on modern ground-based telescopes... A super-scope on the ground would probobly not be quite as high resolution, but they can get close with spysat-derived adaptive optics. They can obviously gather much more light than HST can, since their aperature is far, far bigger, particularly now with multi-primary-mirror scopes. And they can also make somewhat sterioscopic images by combining multiple telescopes' images into one image. The scopes' can even be on the other side of the planet, mitigating the "weather excuse." ...so how valuble is that last fraction of an arcsecond and quasi-UV optics?

---

"We need to build upon what we have already accomplished. If you just throw away everything you have and spend your money re-buying it, you'll never have money to buy something new. For one thing, we have to demonstrate to congress that space assets are not multi-billion dollar gum wrappers. We have to prove that assets can be retained and built upon."

And we can... with a new telescope. I think you are ignoring the economics of the whole mess to champion a renewed sense of worth in exsisting space hardware, perhaps even a psychological shift from the acceptability of "expendable hardware" in the face of the "wisdom" of recycling.

It really is going to cost about as much to "recycle" Hubble as it would be to build a brand new one. On a more general note, there is a good reason for rockets to be expendable, because you need not build them as strong (heavy) or include provision for recovery (heavy). It really is more economical to build a brand new cheap rocket unless you are aiming to fly many many times a year, and so on.

RobS · 2004-07-20 16:15:21

Regarding the question of why we need a reusable solar-ion tug:

1. It would allow EELVs to launch almost twice as many satellites at once; four large geosynch satellites and a xenon (or argon?) propellant tank could dock to a solar-ion tug and be pushed to geosynchronous, where the satellies would separate and "walk" to their final place. This would cut launch costs (though it would also depress an already small commercial launch market!). The tug would then return to LEO for reuse (which it could do in a month or so, since it wouldn't have payload).

2. It would allow EELVs to be used for most of launches for the moon and Mars instead of a SDV or other heavy-lift vehicle. Why use six EELVs when two or three will do, especially if, as I think you note in another posting, the factories can only turn out so many per year? If the Delta-IV heavy can put 25.7 tonnes into LEO, best that it all be one payload, like a Mars hab, ERV, or a cargo pallet. To push them to Lagrange 1, one needs about 5 or 6 tonnes of ion engine propellant; from there to Mars, 5 or 6 tonnes of hydrogen and oxygen or another tonne or so of ion propellant. With a chemical propulsion system one will need at least 2, probably 3, 25.7-tonne propulsion stages to push 25.7 tonnes to Mars.

Of course, you can't use solar-ion to push humans to Lagrange; they'd fry in the Van Allen Belts. The disadvantage of solar ion is that you have to plan way in advance because transit to lagrange takes six months or so, and another 12-18 months to Mars (if you use ion all the way). But it's much cheaper to develop than nuclear engines, has no political and emotional downside, and Prometheus is already developing an electric propulsion system that is probably about 1/5 to 1/10 as large as needed (Prometheus will put out 50 to 100 kilowatts of nuclear electricity; a solar ion tug needs about 450 kilowatts of power).

-- RobS

BWhite · 2004-07-20 17:03:27

That 2010 deadline for ISS? We do that only if everything falls perfectly into place.

Already the politicians are circling to extend shuttle orbiter.

Re-certification? After spending $1.1 billion on return to flight, all Congress has to do is change the rules and define orbitrer as re-certified.

Euler · 2004-07-20 17:14:01

Modern telescopes are like computers. When they fist come out, they are great. After a few years, they are average. After a few decades, they belong in a museum.

We could send up a telescope that is much better than hubble for less than the cost of the repair mission. We could also build better telescopes on the ground for much less than the cost of fixing Hubble.

First, I don't believe you when you claim ground-based telescopes are as good as Hubble. Ground-based telescopes are getting better, but they still don't come close to the resolution of Hubble. Hubble is not about "experience with space operations", it's about imaging celestial objects that bring much more science information than we have ever had before.

The latest ground based telescopes aren't as good as Hubble. They are much better than Hubble. Hubble can achieve an angular resolution of about .1 arcsecconds. That was better than any ground based telescope could acheive when Hubble was built. However, the new VLT array (which costs 1/7 as much as Hubble) will have a resolution of .001 arcsecond when operation in full interferometric mode. That is right, the VLT has a 100 times better resolution than Hubble. It also has 50 times more light gathering power.

GCNRevenger · 2004-07-20 17:45:11

Sooo now that Hubble or any optical ST has been trounced by the VLT... that leaves the near-UV capability. How important is that? Can the Chandra XST operate in a similar spectrum? Can a UV scope' be built on Earth? ... Hubble has been a magnificent tool, but it was developed with the purpose of defeating atmospheric interference, and that is all is special about it. Now that we have adaptive optics, we don't even need that anymore... Hubble's time is over.

Remember, all our telescopes down here are space telescopes too, they just have the atmosphere in the way

---

December 31st 2010 at 2359 EST the last orbiter must be wheels-down, or we can write off NASA ever getting to Mars... then the only thing that would save us is if another Shuttle blew up or the ISS had an "incident"... it would drag on forever until somthing gave way, and that would be the end of NASA's manned spaceflight.

It is not within the power of the Congress to declare a vehicle to be recertified or not, that is a matter for engineering review, but they can order that it be done.

---

As for a tug, I still see very limited benefit for a Lunar or Martian expedition. There aren't going to be that many launches to begin with, barring construction of a large Martian ship in orbit piecemeal, and the ion tug still requires enough fuel that it will cut into payload masses signifigantly in order to avoid having to make a second tiny launch for ion drive fuel.

Lockheed is making noises about a fatter Atlas-V and Boeing could make a stretch Delta-IV where you start talking about 40MT loads. You could put substantial masses on the Moon with only two shots (1 for payload/lander/CEV, one for cryogenic TLI stage) and do it quickly instead of waiting for the tug... plus, you will need to build the "Fast" way for manned flights anyway, the argument will be that since we aren't doing much on the Moon, just build two TLI stages and buy an extra EELV+ flight and save the trouble of fooling with a tug.

As for MARS, its SDV all the way. Three, perhaps four launches total per mission launched directly, perhaps an equal number of EELV+ for extra fuel without NTR... no need for the ion tug really, as it would have to be obcenely big to push 40MT loads, require large amounts of rare Xenon, and could not accompany the payload to aerobrake... would it be able to avoid atmospheric entry on the Mars end while the payload enters?

GraemeSkinner · 2004-07-21 09:45:03

Sooo now that Hubble or any optical ST has been trounced by the VLT... that leaves the near-UV capability. How important is that? Can the Chandra XST operate in a similar spectrum? Can a UV scope' be built on Earth? ... Hubble has been a magnificent tool, but it was developed with the purpose of defeating atmospheric interference, and that is all is special about it. Now that we have adaptive optics, we don't even need that anymore... Hubble's time is over.

Bit off topic for this thread but anyhoo...
Can adaptive optics work at correcting the atmospheric interference for a UV scope on Earth? With the atmosphere filtering a great deal of UV I'm not sure how adaptive optics would overcome this, I know how they work at visible light wavelengths (well in principle, not in depth ) Anyone studied adaptive optics on here?

Graeme

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