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Thread: Moving Hubble near ISS for frequent maintenance?

  1. #61
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    Hi, IIRC, the moon is laden with Dust.....more than can be imagined.
    I should think this would be one....just One of the problems embraced with
    having a telescope on that distant orb. And how would you communicate with
    such an device on the other side of the moon, save perhaps...a satelite in a
    lunar polar orbit,with it's directed antennae tracking such. The challenges are formidable. But interesting.
    Best regards, Dan

  2. #62
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    Communication would be the easy part. Hardwire contact with a base camp that has access to a communication system at the poles, or on the near side.

    Also, there are craters on the near side that have total lack of contact with sunlight, though some Earthshine could be a periodic headache depending on the orientation of the crater through the full lunar orbit as it rolls slightly on axis, which means you've only got to get the signal out of the crater and to a communications system just over the crater ridge.

    I'll concede the dust issue, but this could be mitigated by keeping the aperture of the scope far enough off the ground. Dust does get kicked up, but to kick it up more than a few meters really requires some deliberate effort, and being in the dark constantly means you're not seeing the dust kicked up by ionization from solar particle bombardment. Puts it all back on picking the right crater to host the beastie.

  3. #63
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    knew about the James Webb Telescope, and I agree that it is an excellent advancement in orbital telescopes. However, it does not have any optical capability, as Hubble does.

    The loss of optical capability from orbit isn't as bad as it sounds. Since the Hubble was developed, terrestrial telescopes have made tremendous advances and they cost much less than orbital telescopes. Personally, I believe we should concentrate our limited astronomy dollars on terrestrial telescopes for those optical wavelenghts that can penetrate the Earth's atmosphere and orbital telescopes for wavelenghts (e.g. gamma, x-ray) that don't penetrate the atmosphere. That would seem to give us the most capability for the money.

  4. #64
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    Probably the best means to create a safe haven would be to send up a Bigelow inflateable and be done with the issue.

    The Hop as I recalled was close to the 1 billion for everything back in 2004 these were the plans for shuttle would not fly to a place were they could not seek refuge.

    Hubble Origins Probe (HOP)

  5. #65
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    Hi, In my opinion, Hubble ST has been and continues to be one of the most meritorious instruments we have ever built, and judging from the extraordinary demand for time on it (quite a que as I understand), we should surely do what is required to maintain and save such an extraordinary device, especially because it is in the optical spectrum.
    If boosting it in the neighborhood of the ISS would promote it's support, and further it's carreer, I should be in favour.
    Question: Can anyone shed light on the ' unstable orbit' of ISS ? Would a higher orbit benefit both ISS and Hubble ST ? Would they benefit from some
    simple ION propulsiion to reach such orbit? Or....could you boost enough fuel
    into low orbit for the shuttle to employ in it's main fuel tank to perform these tasks...rather than jetison the main fuel tank ,so as to accomplish such tasks, and THEN send it to burn up.( tasks such as retrieve HST...boost to higher orbit and re-deploy ). Is there any merit to such a scheme? Could you store enough
    of a fuel tank in the cargo bay on lift to have for boosting the HST once in orbit, remove and fasten the smaller tank eva, catch HST ,retrieve,boost, and
    return to earth? Tall orders,I guess. But this is the kind of work we should be good at , before we think about other planets.
    Of course, there may be easier ways. And...your thoughts..?
    Best regards, Dan

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    The ISS is affected by the very outer atmosphere as the solar energy causes fluctuations in the atmosphere. The ISS was designed for reboost by shuttle or Soyuz, small raises of the orbit. This was designed into the system.
    The shuttle's tank is basically empty when it reaches orbit, they do carry small reserves. Were it kept with the orbiter after MECO, it would take more OMS fuel to get them both into a circularized orbit at OMS2 burn, but I imagine it's do-able. Then you have a basically empty tank in very low orbit, then what? The shuttle main engines aren't restartable, and there are not "rocket motors" on the ISS. The shuttle OMS and RCS engines cannot use the H2/O2 from the tank, they use different propellants.
    I'm not sure what taking the ISS to a significantly higher orbit would do to affect accessability by shuttle, Progress or Soyuz...certainly more fuel used to get there.
    Getting HST to the ISS orbit inclination, I just don't see that as feasible. The ISS orbit was designed for the Russian participation (and maybe for Earth surface coverage? don't know). The HST orbit is where it's high enough to not require frequent reboost, but low enough for easy STS access, with a lower energy low inclination launch.
    Lots of issues, but the most direct approach says use the shuttle. That's the answer "today".

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    Quote Originally Posted by Larry Jacks View Post
    knew about the James Webb Telescope, and I agree that it is an excellent advancement in orbital telescopes. However, it does not have any optical capability, as Hubble does.

    The loss of optical capability from orbit isn't as bad as it sounds. Since the Hubble was developed, terrestrial telescopes have made tremendous advances and they cost much less than orbital telescopes. Personally, I believe we should concentrate our limited astronomy dollars on terrestrial telescopes for those optical wavelenghts that can penetrate the Earth's atmosphere and orbital telescopes for wavelenghts (e.g. gamma, x-ray) that don't penetrate the atmosphere. That would seem to give us the most capability for the money.
    Actually, now that you mention this, this is probably the best way to go. If Congress refuses to add anymore money to space exploration and studies, that is. Of course, I'd much rather see a larger budget for NASA and space science than what we currently have, but that's getting into politics and I'm not going to bring that up any further here.

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    Quote Originally Posted by gaetanomarano View Post
    the price of the Hubble-Progress-adapter may vary depending of the country that develops and build it... maybe $100M in USA... $50M in Europe... $20M in Russia (that has a great experience with automated vehicles)... $10M in China... $5M in India...
    But how does the docking gadget come into place?
    if the Prorgess is so gentle and safe to dock the (manned) ISS it can be equally gentle to dock the Hubble
    also,
    AFAIK a Progress (or Soyuz) docking still gives much more of a jerk than grappling with the RMS.
    the real target of the Progress is NOT the (big) ISS but its (small) docking port (very much smaller than Hubble!!!)
    Size is not an issue at all, but Russian spacecrafts use a two ended rendezvous system which is mandatory. You had to install a Kurs passive side onto Hubble first.

  9. #69
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    Quote Originally Posted by Dave J View Post
    there are not "rocket motors" on the ISS.
    Not sure what you mean by "rocket motors" but Zvezda has engines (UDMH/N2O4) suitable for orbit corrections and reboosting.

  10. #70
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    Quote Originally Posted by Dave J View Post
    The ISS is affected by the very outer atmosphere as the solar energy causes fluctuations in the atmosphere. The ISS was designed for reboost by shuttle or Soyuz, small raises of the orbit. This was designed into the system.
    The shuttle's tank is basically empty when it reaches orbit, they do carry small reserves. Were it kept with the orbiter after MECO, it would take more OMS fuel to get them both into a circularized orbit at OMS2 burn, but I imagine it's do-able. Then you have a basically empty tank in very low orbit, then what? The shuttle main engines aren't restartable, and there are not "rocket motors" on the ISS. The shuttle OMS and RCS engines cannot use the H2/O2 from the tank, they use different propellants.
    I'm not sure what taking the ISS to a significantly higher orbit would do to affect accessability by shuttle, Progress or Soyuz...certainly more fuel used to get there.
    Getting HST to the ISS orbit inclination, I just don't see that as feasible. The ISS orbit was designed for the Russian participation (and maybe for Earth surface coverage? don't know). The HST orbit is where it's high enough to not require frequent reboost, but low enough for easy STS access, with a lower energy low inclination launch.
    Lots of issues, but the most direct approach says use the shuttle. That's the answer "today".
    Hi, Thank you for your excellent reply. Could you amplify your mention of Shuttle main engine restart.....esp: what is required for MER; Hydrazine/oxy ?
    I'm curious. I know that this is only academic Asumming that "That" could be refurbished EVA, we then have the chore of electrically pumping the
    fuel load brought up in the cargo bay ..into the main fuel tank. Upon acceleration, the load now enjoys gravity and settles to the bottom for use,
    the orbiter's main engine being controlable. The internal tank is jetisoned and the cargo bay is ready for HST capture; to safely boost to higher orbit.
    Or is there some peculiar problem with tankage of liquid propellant and oxidizer in the vaccuum of space? Are precision SRB's the "ONLY answer" ?
    Or...do you surmise that anything we boost into "some" orbit is doomed in short order because it just can't be done? ( my background was diesel submarines, and our problems were simple by comparison).
    Again, my questions are acedemic, and driven by curiousity. I appreciate your effort in reply, and thank you in advance for that courtesy.
    Best regards, Dan
    Last edited by danscope; 2006-Dec-18 at 01:25 AM. Reason: typo

  11. #71
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    Quote Originally Posted by danscope View Post
    Hi, Thank you for your excellent reply. Could you amplify your mention of Shuttle main engine restart.....esp: what is required for MER; Hydrazine/oxy ?
    I'm curious. I know that this is only academic Asumming that "That" could be refurbished EVA, we then have the chore of electrically pumping the
    fuel load brought up in the cargo bay ..into the main fuel tank. Upon acceleration, the load now enjoys gravity and settles to the bottom for use,
    the orbiter's main engine being controlable. The internal tank is jetisoned and the cargo bay is ready for HST capture; to safely boost to higher orbit.
    Or is there some peculiar problem with tankage of liquid propellant and oxidizer in the vaccuum of space? Are precision SRB's the "ONLY answer" ?
    Or...do you surmise that anything we boost into "some" orbit is doomed in short order because it just can't be done? ( my background was diesel submarines, and our problems were simple by comparison).
    Again, my questions are acedemic, and driven by curiousity. I appreciate your effort in reply, and thank you in advance for that courtesy.
    Best regards, Dan
    The SSMEs run on hydrogen and oxygen. Probably there is some conceivable way of hooking them up to additional fuel and revving them up again, but there's no way in the present safety-paranoid environment that a space shuttle is going to launch with a cargo bay full of rocket fuel.
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  12. #72
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    Hi, Would that mean boosting up fuel by itself, and shuttle rendezvous with that fuel to accomplish such a mission? I appreciate the present atmosphere
    concerning safety, which must needs come before economy and super-efficiency.
    I am reminded of an expedition to save a B-29 which had a forced landing
    on Greenland, and sat there for some 50 years, and , having rebuilt it for ferrying to the nearest FBO and on to the US, had a small gasoline generator which was jury rigged in the after compartment. Too Bad it wasn't so well secured. On taxi and then takeoff, it got jostled enough to spill and catch fire, losing the whole project, one of the last flying B-29's left. Pity.
    Well, nothing's easy.
    Best regards, Dan

  13. #73
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    At one time, pre-Challenger, they were planning on flying satellites in the payload bay that were attached to Centaur stages, also LO2/LH2. Thee was a flight that actually did some EVA work where they did cryogenic plumbing practice, attaching and disconnecting lines, pumping cryo (I think) and the like. This all went away after Challenger, and only solid motor boost stages flew after that.
    I need to check, but from what I read, the SSMEs by their design are really hard to start and stabilize. Lots of ground support equipment on the pad goes into getting them going. I think one of the strikes against using SSMEs on the planned Earth Departure stage of the Aires V is the difficulty and penalties of designing in this restart capability.
    Now, theoretically, the Shuttle could meet the HST, attach a boost stage to it (which it's structure wasn't designed for, load bearing wise)and send it higher. Considerations include stress on the telescope itself (very fragile), designing and building the stage, then flying the mission. It would seem a very low thrust ion booster would be neat, but the burns may be on the order of days or weeks, and science would have to stop to perform them.
    Oh, and the booster would need maneuvering capability and a guidance system, whatever it's propulsion method.
    Frankly, the shuttle is the gentlest and most dependable way to do it. It's done it before very successfully, the procedures are established, and as pointed out before, the shuttle has made some hundred safe flights without the ISS "safe haven"...seems so many have lost their nerve when it comes to spaceflight...unfortunate.
    I'd like to see Shuttle flying up until the next program is ready to go...2010 is just an arbitrary date and sets us up for a long gap in manned flight...but I digress badly..

    Dave

  14. #74
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    Quote Originally Posted by Larry jacks
    The loss of optical capability from orbit isn't as bad as it sounds. Since the Hubble was developed, terrestrial telescopes have made tremendous advances and they cost much less than orbital telescopes.
    The while it is not traumatic it however can not be replace by earth adaptive optic telescopes which are at there limits especially with the increasing global warming.


    Quote Originally Posted by Larry Jacks
    Quote Originally Posted by DOOMMaster
    knew about the James Webb Telescope, and I agree that it is an excellent advancement in orbital telescopes. However, it does not have any optical capability, as Hubble does.
    Actually, now that you mention this, this is probably the best way to go. If Congress refuses to add anymore money to space exploration and studies
    JWST is delayed for launch and over budget not to mention no where even close to being assembled for testing.

    Quote Originally Posted by Dave J
    The shuttle's tank is basically empty when it reaches orbit, they do carry small reserves. Were it kept with the orbiter after MECO, it would take more OMS fuel to get them both into a circularized orbit at OMS2 burn, but I imagine it's do-able. Then you have a basically empty tank in very low orbit, then what? The shuttle main engines aren't restartable, and there are not "rocket motors" on the ISS. The shuttle OMS and RCS engines cannot use the H2/O2 from the tank, they use different propellants.
    So true that it is nearly empmty and is the wrong fuel type for the Zvezda engines or for the shuttles OMS. Thou the main problem for reuse of what fuel is there is in that the tank needs to be repressurized before you could use it. Another use of what is there could be for the fuel cells to make power or just save the LOX and dump the Hydrogen overboard as the Russian unit does via the waste water reuse.

    Quote Originally Posted by Dave J
    At one time, pre-Challenger, they were planning on flying satellites in the payload bay that were attached to Centaur stages, also LO2/LH2. Thee was a flight that actually did some EVA work where they did cryogenic plumbing practice, attaching and disconnecting lines, pumping cryo (I think) and the like. This all went away after Challenger, and only solid motor boost stages flew after that.
    I do not recall this, I would have hoped that they would have though and that more work was to have continued with it since reusuability for vehicles in the fule may depend on this.

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    Hi Dave, Thanks for your reply.
    My scheme was to capture HST after the Shuttle was refueled,allowing it to be accelerated within the cargo bay, and deployed safely at it's new position.
    Self boosting such a delicate structure is daunting,at best,I suppose.
    I wonder....just what the precise difficulties in re-fueling the shuttle would be.
    I,too, should like to see Shuttle and Hubble enjoy a robust and usefull carreer
    greater than what some have planned. Thanks again for your reply.
    Best regards, Dan

  16. #76
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    Quote Originally Posted by SpaceNutNewmars View Post
    The while it is not traumatic it however can not be replace by earth adaptive optic telescopes which are at there limits especially with the increasing global warming.




    JWST is delayed for launch and over budget not to mention no where even close to being assembled for testing.



    So true that it is nearly empmty and is the wrong fuel type for the Zvezda engines or for the shuttles OMS. Thou the main problem for reuse of what fuel is there is in that the tank needs to be repressurized before you could use it. Another use of what is there could be for the fuel cells to make power or just save the LOX and dump the Hydrogen overboard as the Russian unit does via the waste water reuse.



    I do not recall this, I would have hoped that they would have though and that more work was to have continued with it since reusuability for vehicles in the fule may depend on this.
    Hi, Can you say what concerns there are for pressurization of the fuel tank? In fact, in space, a single 60 cubic foot Scuba tank would expand to sufficiently pressurize even that tank. Remember: we are not looking for super performance at lift-off to fight gravity . I was only thinking that the performance of the main engines has nothing to do with that required for initial boost to LEO, but simply to get "Some performance ,even at 20% throttle up (which in orbit ,with no gravity,
    and in a vaccuum would be spactacular....I should think). And enjoy the
    piloting astronautics of the Crew toward their objective: Deploy HST with any upgrades and with it's solar panels deployed as advertised, and enjoy HST for the better future . For myself, I see this as a noble purpose and worthy of
    the talent and resource of NASA and those skillful individuals they work so hard to train.
    Best regards, Dan

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    I don't think I can add much to this discussion, but I am curious as to whether there is a reason why the ISS wasn't designed with its own telescope at least equal to Hubble.

    Also, what does gaetanomarano mean when he refers to the mass of something in mT. Is this not millitesla? How is mass measured in Tesla? what does magnetic field strength have to do with mass? Does he mean millitons? If so, why doesn't he just say kg like every one else?

  18. #78
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    Quote Originally Posted by lti View Post
    I don't think I can add much to this discussion, but I am curious as to whether there is a reason why the ISS wasn't designed with its own telescope at least equal to Hubble.
    A space telescope like Hubble needs two things (well, a bunch, but two are worth mentioning here): an extremely stable platform, and an extremely clean environment. The ISS fails on both counts, though they could get by on the former so long as the astronauts remained completely motionless for the duration of any observations.
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  19. #79
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    Quote Originally Posted by danscope View Post
    Hi Dave, Thanks for your reply.
    My scheme was to capture HST after the Shuttle was refueled,allowing it to be accelerated within the cargo bay, and deployed safely at it's new position.
    Self boosting such a delicate structure is daunting,at best,I suppose.
    I wonder....just what the precise difficulties in re-fueling the shuttle would be.
    I,too, should like to see Shuttle and Hubble enjoy a robust and usefull carreer
    greater than what some have planned. Thanks again for your reply.
    Best regards, Dan
    I'm pretty certain, if we're still talking of moving HST to an ISS orbit, that the shuttle us not able to do it safely. Even with the ability to dock with the HST and boost it by whatever available propulsion, you deal with the unfortunate aditional mass of the Shuttle itself, over 100 tons.

    In a best case scenario, I expect it would take many shuttle missions. Capture Hubble with the probably still existing cradle hardware, tuck it in, burn with OMS for all you have (no room in the cargo bay for fuel tanks) then leave,,,then another mission, and another...I couldn't guess how many it would take...very, very many.

    The ISS and Hubble are in orbits that are incompatible by today's technology, based on both HST physical limitations and mission needs of the telescope, as well as propulsion capabilities. Unfortunately, the two will never meet. Not to say that the next system won't be different, if it's deemed appropriate.

    BTW, mT has to do with mass Tons. I'm guessing about 2000lb/ton, there are so many types of tons...

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    well apparently mT is used in some parts of the world to refer to metric tonnes (1000 kg) to distinguish from the various other tons in the world.

    however its a very dumb way of writing it because metric tonnes should use the symbol t, as T is used already for Tesla. mT would be millitesla.

    Personally I find the fact that the term ton has so many different values (at least 3 that i know of) means that it is of no usefullness as a unit.

    But this is neither here nor there.


    Thats an interesting point ToSeek made about needing a stable platform.
    Thanks.

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    the 'next system' will be the James Webb facility - which will not be in Earth Orbit at all.


    As for the orig. subject...it would take hundreds and hundreds of millions of dollars - a LOT more than a Hubble servicing mission - to move Hubble into the ISS orbit. 3km/sec of Delta V required - 10x much as the Shuttle can provide on any one mission.

    Also - there are other problems with Hubble at ISS Orbits. The ISS is at a higher linclination and thus due to seasonal changes can undergo night and day passes that vary a huge ammount - not just 45 mins of one and 45 mins of the other. That would be very non optimal for Hubbles thermal design and battery capacity.

    Furthermore - the ISS orbit is littered with crud - exhaust gasses, water dumps etc etc etc - all stuff that would contaminate the mirror of Hubble and degrade its performance. The very reason Hubble has no thrusters of its own is because they would contaminate the mirrors.

    There is no way to sensible propose adjusting the very aging Hubble to the ISS orbit - when, even if you ignore the spacecraft management issues, the cost of doing that orbit change is possibly as much as an order of magnitude greater than simply launching a replacement on an EELV.

    FYI Progress/Soyuz/ATV use russian hardware on the ISS to allow automated docking. US politics would not allow for the purchase of either that hardware, nor the 15+ Progress vehicles required to do the orbit shift.

    When you don't understand the principles or limitations - it is very very easy to say "move it to ISS". When you scrach the surface, even just a tiny ammount, it soon becomes very very obvious that it is not only something that would vastly more expensive than launching a replacement, but also a stupid thing to do from a spacecraft operations perspective. No one in their right minds could seriously propose this as practical or sensible.


    Doug

  22. #82
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    To create a platform if the cradle for the hubble is available one could attach it to the outside of the ET after placing it to the points on the hubble. Also on this same mission in the cargo bay could be brought up an engine capable of burning the excess fuel in the Et. Along with this a small amount of helium to repressurize the ET. Of course you still need to add the controls neccessary to fire the engines and such but it could be done.

    So do we have an engine capable of the 3km/sec of Delta V?

    As for moving it to the ISS orbit as Doug put it, the conditions that it would be in make it a bad place for it to reside in.

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    Quote Originally Posted by gaetanomarano View Post
    I can't calculate it, but, as I've explained in my previous posts, the distance between the Hubble and the ISS is a minor problem (compared with the change of orbit and altitude!) since the Hubble don't need to be reboosted every day but only when it goes too away from ISS or needs some maintenance 8and that can be done with a Progress)
    If you can't calculate it then how can you say it is a minor problem?

    I went and found an orbital calculator on the web (something that you apparently cannot do) and discovered that the difference in ISS altitude and ISS+100m is virtually the same (to my surprise). At least in the significance as the following statement.

    If HST is in orbit 50m higher than ISS, and both travelling the same speed, then the ISS has travelled 157m farther (from Earth's perspective) than the HST. Therefore, the two will travel 2.5km farther from each other each day. Eventually, without continuous adjustments, the two will be near each other but at different inclinations. That is a big problem.


    Quote Originally Posted by gaetanomarano View Post
    I don't know, but this is not important, since, before a Shuttle/Hubble repair mission, the Hubble can be reboosted with a Progress to be at a reasonable/right distance from ISS.
    If you don't know, then how do you know it's not important? The people here who do know, say it's important, and why it's important. In most of the civilized world, this negates your argument.

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    Quote Originally Posted by gaetanomarano View Post
    the price of the Hubble-Progress-adapter may vary depending of the country that develops and build it... maybe $100M in USA... $50M in Europe... $20M in Russia (that has a great experience with automated vehicles)... $10M in China... $5M in India...
    These numbers you've thrown out are based on what? Wishful thinking?

    if the Prorgess is so gentle and safe to dock the (manned) ISS it can be equally gentle to dock the Hubble
    also, the real target of the Progress is NOT the (big) ISS but its (small) docking port (very much smaller than Hubble!!!)
    The docking port on the ISS is a much bigger target than the small grapple fixture on the HST. In addition, the ISS docking port is designed to absorb some of the energy from docking. HST is not.

    if the Hubble (built with space-grade technologies) survived the very high stress and acceleration of the lanunch, can easy survive some gentle moving with the Progress (like the much complex ISS does!)
    Yes, HST survived launch when it was safely cradled in the cargo bay of the Shuttle and its solar arrays weren't deployed. This is not the same scenario at all.

    near the ISS Hubble can be repaired and ugraded many times, so, its operational life (and the total time of observation) will be INCREASED VERY MUCH
    How many years are in an "INCREASED VERY MUCH" and at what cost? The next service mission will give the HST a nominal life extension of about 5 years and take it to about 2013. The Shuttles are retired in 2010 and it is unclear whether Orion will have the necessary capabilities to perform an HST service. So what is the point?

    the "cushion" you quote is very close to a (medium) weather delay and is very much smaller than recent (medium) Shuttle flights' delays...
    Cite?

    true... we must add other costs to the ($330M) 15-Progress' price, but, also with at $500M or $800M, move the Hubble near the ISS and multiply its operational life WORTH THE PRICE

    .
    No, it's not worth the price even if it could be done. Since you seem unwilling to see the downside to any of your ideas, let me lay them out:

    1. You have no idea what the total cost is, so claiming its cheaper than a Shuttle mission is just wishful thinking.
    2. 15+ attempts to dock with a delicate, precision instrument (HST) using a tool (Progress) that was not made for the job. Any problems in docking could ruin the telescope.
    3. What toll does 15+ accelerations do to the instruments, mirror or to the solar panel attachments?
    4. Loss of observing time from the repeated downtimes necessary for each docking. What are the costs for this?
    5. You would be moving the telescope from a relatively clean orbit to one that is filled with exhaust particles and other detritus that has escaped from the ISS and Shuttles.
    6. You haven't even considered where the money is going to come from for all of these service missions. There is currently money for one more mission and that's it. At this point, it seems unlikely that Congress is going to fund anymore service missions to Hubble, regardless of what orbit it is in.
    7. In 2010 you lose the only vehicle capable of doing a service mission and it is unclear whether Orion will have the required capability.


    There are probably more reason, but these are enough to show this idea has no merit whatsoever.

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    Quote Originally Posted by djellison View Post
    the 'next system' will be the James Webb facility - which will not be in Earth Orbit at all.


    As for the orig. subject...it would take hundreds and hundreds of millions of dollars - a LOT more than a Hubble servicing mission - to move Hubble into the ISS orbit. 3km/sec of Delta V required - 10x much as the Shuttle can provide on any one mission.

    Also - there are other problems with Hubble at ISS Orbits. The ISS is at a higher linclination and thus due to seasonal changes can undergo night and day passes that vary a huge ammount - not just 45 mins of one and 45 mins of the other. That would be very non optimal for Hubbles thermal design and battery capacity.

    Furthermore - the ISS orbit is littered with crud - exhaust gasses, water dumps etc etc etc - all stuff that would contaminate the mirror of Hubble and degrade its performance. The very reason Hubble has no thrusters of its own is because they would contaminate the mirrors.

    There is no way to sensible propose adjusting the very aging Hubble to the ISS orbit - when, even if you ignore the spacecraft management issues, the cost of doing that orbit change is possibly as much as an order of magnitude greater than simply launching a replacement on an EELV.

    FYI Progress/Soyuz/ATV use russian hardware on the ISS to allow automated docking. US politics would not allow for the purchase of either that hardware, nor the 15+ Progress vehicles required to do the orbit shift.

    When you don't understand the principles or limitations - it is very very easy to say "move it to ISS". When you scrach the surface, even just a tiny ammount, it soon becomes very very obvious that it is not only something that would vastly more expensive than launching a replacement, but also a stupid thing to do from a spacecraft operations perspective. No one in their right minds could seriously propose this as practical or sensible.


    Doug
    Hi Doug, You illustrate an important concept: Contamination. I think this changes the picture. Local service on demand would generate more of what we don't need, apparently. Are you theoretically opposed to boosting Hubble's orbit even minimally to extend life, or is it just impossible?
    And thankyou for your kind service to my inquiry.
    Best regards, Dan

  26. #86
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    Quote Originally Posted by danscope View Post
    Are you theoretically opposed to boosting Hubble's orbit even minimally to extend life
    The limiting factor for life will be hardware failure, not orbital decay - but there would be no harm in throwing it up as high as fuel will allow with the last servicing mission - minimise the torque generated on the arrays from the upper atmosphere.

    Some would argue ( perhaps rightly ) that the servicing mission - which you can price at anything between about 0.5 and 1.5 B$ depending on how you split the maths - is too expensive and that for the money it would make more sense to launch a replacement. However I think that misses an important point - Hubble is an international 'asset' that most space-aware members of public hold dear and in some cases, you have to put the emotional value of the thing higher than the financial value of the thing. It would be a fitting near-final-fling for the Shuttle program - something that, despite all it's negatives - one can point to and say "yes - but look what it achieved"

    Doug

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    Hi Doug, Thanks for the reply. I should hope that,apart from the batteries on board, that Hubble will out last our greatest expectations. Here's to all possible success with the return flight.
    Best regards, Dan

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    Quote Originally Posted by djellison View Post
    The limiting factor for life will be hardware failure, not orbital decay - but there would be no harm in throwing it up as high as fuel will allow with the last servicing mission - minimise the torque generated on the arrays from the upper atmosphere.

    Some would argue ( perhaps rightly ) that the servicing mission - which you can price at anything between about 0.5 and 1.5 B$ depending on how you split the maths - is too expensive and that for the money it would make more sense to launch a replacement. However I think that misses an important point - Hubble is an international 'asset' that most space-aware members of public hold dear and in some cases, you have to put the emotional value of the thing higher than the financial value of the thing. It would be a fitting near-final-fling for the Shuttle program - something that, despite all it's negatives - one can point to and say "yes - but look what it achieved"

    Doug
    I think there would also be significant political consequences to going from a servicing mission to a replacement mission - people would be asking, "Okay, if it was such a good idea this time, why wasn't it a good idea the last four times?"
    Everything I need to know I learned through Googling.

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    Quote Originally Posted by danscope View Post
    apart from the batteries
    Realistically, it will be the gyros I would have thought.

    Doug

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    Quote Originally Posted by djellison View Post
    Realistically, it will be the gyros I would have thought.

    Doug
    It would be the gyros. The batteries are original equipment (i.e., they've lasted since 1990), while this is the third time a servicing mission has had to deal with the Rate Sensing Units (gyros).
    Everything I need to know I learned through Googling.

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