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Clock Ticking for Hubble
DoraLives writes "Ok then, what are we going to do with Hubble? Eventually, it MUST come down. The New York Times has a piece that addresses this less than pleasant (at least for the astronomical community) subject. Additionally "The decision about what happens then has been complicated by the breakup of the Columbia." Read all about it."
Why would that complicate things? All the incident proved was what we know already. Besides, Hubble's done some great things, and of course it'll have to come down eventually. We just have to move on and produce a successor.
Bash script for FP whores
Of course, Taco Bell will put a big floating bullseye in the ocean and if some titanium part of hubble hits it everyone in the US wins a Taco!
Wooo Hoooo!
Why don't we get some other country
to foot the bill on boosting it
into a sustainable orbit and paying
for the initial maintenance after
2010. I'm sure that an India or
Taiwan would be willing to take it on
for less than $500 million.
Click here
Reality has a liberal bias
NASA has long planned to end Hubble's spectacular run and bring it down in 2010 to make way in the budget for the James Webb Space Telescope, scheduled to be launched in 2011.
Theres a gap there in time where we wont have a telescope up there. this will be the end of the world, as we wont be able to see the asteroid comming at earth in time to send our best deep crust drillers to drop a nuke in it and split it up!
I just find is pathetic that the U.S. can't find $600m to refurb the HST. We're spending about twice that EVERY DAY on operations in Iraq.
Just pull the troops out two days earlier and there you have it... enough cash to service the Hubble twice!
My opinion is that the HST should be retrofitted with a small nuclear power source (like those on the Voyager series) and send out of the solar system. But unlike previous missions were the probes were sent past the outer planets, we should send HST perpendicular to the Earth's orbit, so we can look back "down" on ourselves and surrounding stars/planets.
I can't recall if the solar system plane is about parallel to the galactic plane, but if so this would also give us a tremendous perspective on the galaxy that we haven'y had before. Yea, yea it would take a decade or two to get to a distance that would mean anything astronomically, but it has to happen some time, why not now.
Article X: The powers not delegated... by the Constitution...are reserved...to the people
Hubble is in Low Earth Orbit (LEO). It's got an orbital velocity of around 4KM/Sec.
To raise the orbit far enough to get to the Moon, takes a total deltaV of 7KM/S (or another 3KM/S on it's current speed).
The Earth orbits the sun at around 30KM/S, give or take. So to send something - anything - into the sun requires a deltaV of the same amount: you've got to cancel out the existing 30KM/Sec velocity, otherwise you're just going to send the object into a different orbit around the sun
The fastest any object has left the earth is around 8KM/S for the interplanetary probes (Pioneer, Voyager, Cassini, Galileo etc). That's as fast as the human race has ever gotten anything going[*]. Without a major advance in rocket technology (i.e. away from chemical rockets), that's about as fast as we're going to get anything going, too.
As a reference, the on-orbit manoever capability of the Shuttle, is a total of about 100M/S
Oh, and Hubble has much MUCH less manoever capability than this
This is why things are de-orbited, rather than "sent towards the sun" or further out. De-orbiting from LEO requires only a little "kiss" of deceleration before the orbit intersects the atmosphere, from where friction does the rest. The only exceptions are Satellites in higher orbits (e.g. GPS in the 12-hr / 12,000KM orbits, or Geostationary sats) which tend to be "retired" in slightly higher orbits because these are thought to be more stable over longer (geological) time periods than lower ones, and there's not enough residual manoever capability to lower the orbit enough to graze the atmosphere
[*] = However, we've learnt the trick of gravitational assists which lets Mother Nature (or Newton, or Einstein depending on your religious orientation :-) speed up our probes considerably at the expense of the orbital energy of the planet we're assisting from.
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I'd rather have a bottle in front of me than a frontal lobotomy
I've been an avid avid amateur telescope maker since I was twelve years old. It led to me studying astronomy for a time at Caltech. While I'm a programmer now, it's still a very enjoyable and intellectually stimulating hobby.
While a basic newtonian is a straightforward instrument that can be built by anyone who's good with their hands, telescope making can get as complicated as you want if you're really looking for a challenge. Optical design is still a wide open area of research in mathematics, software engineering, and physics, and some of the more interesting designs take quite a bit of skill to fabricate. That means anyone can make a satisfying telescope, but the hobby will yield a lifetime of interest because there's always new things to learn.
You can construct your own telescope with a primary mirror of 8 inches in diameter for less than $200. It will take quite a bit of work, but it is enjoyable and meditative work. Grinding mirrors is one of the things I do to relax and relieve the strain of coding all day.
A good place to start looking for information is the ATM FAQ. The procedures for grinding, polishing and figuring are pretty involved - you should buy one of the books from astronomy publisher Willman-Bell.
There are a number of people and business who sell inexpensive mirror grinding kits. They will come with a glass mirror blank and an assortment of different sizes of abrasive grits. I would recommend asking on the ATM mailing list (that you can find in the FAQ) when you're ready to order your first kit.
The 8" plate glass kit I bought from Dan Cassaro for my current project set me back $64. When I get done working on the mirror, it will cost me about $35 to have a vacuum coating laboratory aluminize it. Good quality eyepieces cost about $50 - just one will do to start with but it helps to have more.
While fancy equatorial mountings can be expensive to make, it's possible to make a quite servicable altazimuth mount out of common materials like plywood and a few hand tools.
Request your free CD of my piano music.
I'm certain that it would have brain-dead simple to convince GM or Ford or DuPont to spend billions of dollars to build, launch, and maintain something which produces pictures of objects in space. In fact, I seem to recall that NASA had to sue a number of such companies to keep them from launching several other pure science satellites which had no commercial value. Stockholders in those companies were outraged that the attempts of their management to dump billions of dollars into altruistic enterprises were thwarted by evil bureaucrats. Idiot. Get a clue as to what private companies do and why and how they do it.
Hubble was designed to be serviced, on-orbit, by the Shuttle. This is '70s NASA remember which was juust getting the hang of perpetually self-justifying programs. Why do we need a Shuttle? To service Hubble, of course! Ahh, but why do we need Hubble? To give the Shuttle something to do!
Rather less cynically, note that the design life[*] of most unattended satellites is 5 years. After that period of time, enough is going to have started going wrong (fading power from radiation and micro-meteorite damaged solar cells is the classic example) that it's just not worth adding extra redundancy into the design up front to cover it (remember that redundancy = mass consumed that can't be used for the primary purpose of the sat.). Hubble has been up nearly 15 years now, and still has 5 years of useful life in it. That's because all of the things that traditionally go wrong - see the solar cells - have been replaced at least once. Also note that not only was the critical design-flaw in the mirror corrected on-orbit by the first Shuttle service mission (turning what would have been a wasted sat. requiring complete replacement and relaunch into a fully-functioning success), but later service missions have replaced components with improved versions, increasing the capabilities of Hubble enormously. It's like there's been 3 Space Telescopes up there, for the cost of... well, let's not go there. NASA's more than capable of making it look like it's cost less than 3 complete new telescopes, I'm sure...
[*] = as opposed to the actual life which can be much longer, but can't be predicted in advance
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I'd rather have a bottle in front of me than a frontal lobotomy
For everything Hubble has done to further astronomy (and since it was practically the only bright spot of the otherwise maligned space program), they owe it a better end than what they are proposing. To deorbit it and let it burn up with as much thought as one would give to flushing a dead goldfish is just plain wrong.
It should definitely be retrieved and become a piece in the Air & Space Museum's collection.
The moon race isn't the only example, SSI, public education, medicade/medicare are all drastic and sorry failures.
Yeah, not like the shining examples of Amtrak, Worldcom, and Enron.
Consider what you are suggesting for a sec, OK?
(1) Space Shuttles cannot push it up to much higher earth orbit.
(2) hence you will require a propulsion system to be attached to the HST and then launch into a new, higher orbit.
(3) however, the HST is not designed to take such ad-hoc propulsion system.
(4) and neither NASA has such convenient propulsion system sitting around (Air Force does,
IIRC).
(5) in any case, you have to do R&D to find a way to attach such system and safely launch the HST into a new orbit (consider multitude of risks; the major one that I see is supersonic vibration generated by the rocket).
(6) knowing this is NASA, it'd take a decade to get that sort of things built and launched. Waste of the limited resource. They'd rather build a new telescope (or try to build) with that resource.
In short, I guess it CAN be done. But not without additional resource and public support.
-b
> I was just thinking, what happened to the space program is a classic example of why it's better for things to be privatized. I mean, one of the worst possible things that can happen to a government program is
I find myself wondering whether you've every had a job. Surely even the most casual observation reveals that private enterprise doesn't have all the magical properties commonly attributed to it. Failed or discontinued projects in the private sector are a dime a dozen, as are pet projects that get funded on the basis of which manager is the best suck-up rather than on the basis of which best satisfies some other requirement (even if that requirement has no higher social goals than raking more gold into corporate coffers). Waste and "dumbsizing" of good projects seem to be the rule in the private sector as much as in the public sector; you're just less likely to see them in the news or hear them harped on for political exploitation by radio talkjox.
Sheesh, evil *and* a jerk. -- Jade
Hubble is an overgrown version of a digital camera. As CCDs improve, you eventually want to replace the ones up there with better ones. This has already been done a couple of times, but electronics keeps improving.
It also has batteries and solar cells that provide power, and these wear out and have to be replaced.
Hubble needs to point itself at things, and it does so using heavy spinning rotors, which are
turned one way, and by Newton's Law, Hubble
turns the other way. There are 5 of these
"Control Moment Gyros", or CMGs. Being mechanical devices, they wear out and break over time.
You need 3 out of 5 to be working to point Hubble, and if they have an MTBF of 12.5 years (which is pretty good for a mechanical device), then you need to visit every 5 years and replace 2 to keep Hubble running.
Hubble has no propulsion and you don't want any until you are ready to kill it. Fluids sloshing in tanks will mess up your pointing of the telescope, and any exhaust from a rocket will contaminate the optical surfaces. When the Shuttle visits, the thrusters are 50-75 feet away, which is much less of a problem than if your booster pack is on the back end of the telescope only 2 feet from the science instruments.
And yes, IAARS, in fact the first group I worked at at Boeing back in 1981 supplied the graphite/epoxy frame that holds Hubble's mirrors in place.
Daniel
Maybe it's time for the US to test some of their cool new weaponry. They must have SOMETHING neat that was designed to take out high altitude stuff. What better chance to prove it's effectiveness? I mean, the Hubble has to come down anyway, so why not give us all a show?
It's actually worse than that. Orbits at altitudes reachable by the Shuttle decay rapidly, because the atmosphere's a little too thick up there - satellites like the Hubble, with big solar arrays, are particularly vulnerable.
The most important thing that happens on Hubble servicing missions has nothing to do with fixing hardware. The Shuttle catches the Hubble, then fires its maneuvering engines and carries the Hubble up to a higher orbit.
I know this because my company did some computer modeling for NASA to help them predict how often these reboosts would be needed. The amount of atmospheric drag varies with sunspot activity - increased solar output makes the atmosphere "puff up" and makes orbits decay faster.
And guess what? The Space Station is in an orbit reachable by the Shuttle, and also has big solar panels, so it needs reboosting by the Shuttle too.
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-AD