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Waspie_Dwarf

Hubble Stretches Stellar Tape Measure

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Hubble Stretches Stellar Tape Measure 10 Times Farther into Space

Even though NASA's Hubble Space Telescope is 24 years old, astronomers are still coming up with imaginative, novel, and groundbreaking new uses for it. The latest is an innovative technique that improves Hubble's observing accuracy to the point where rock-solid distance measurements can be made to Milky Way stars 10 times farther away than ever accomplished before.

To do this, Hubble observations and subsequent analysis were fine-tuned to make angular measurements (needed for estimating distances) that are so fine that if your eyes had a similar capability you could read a car's license plate located as far away as the Moon!

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Thats brilliant! I wonder what they will think to do with it in 24 more years.

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Thats brilliant! I wonder what they will think to do with it in 24 more years.

It won't be here in 24 years.

With no space shuttle to undertake servicing missions it will eventually fail. If NASA are lucky they will be able to keep it functioning until 2018 when it's successor, the James Webb Space Telescope (JWST) is launched. It is unlikely that NASA will keep the Hubble in service once the JWST is operating.

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It won't be here in 24 years.

With no space shuttle to undertake servicing missions it will eventually fail. If NASA are lucky they will be able to keep it functioning until 2018 when it's successor, the James Webb Space Telescope (JWST) is launched. It is unlikely that NASA will keep the Hubble in service once the JWST is operating.

Maybe parts could be salvaged, i wonder if that would be possible to dismantle it even and piece it back to earth... Seems such a waste.

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Maybe parts could be salvaged, i wonder if that would be possible to dismantle it even and piece it back to earth... Seems such a waste.

How?

There was only one vehicle in history that could do that... the space shuttle. In case you missed it, the space shuttle is no longer in service.

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Posted (edited)

And your point is?

Your link, whilst offering an interesting piece of history, makes no mention of any method of salvaging the Hubble with or with out the shuttle. It does not answer the question in any way, shape or form.

Edited by Waspie_Dwarf

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And your point is?

Human endeavour.

Your link, whilst offering an interesting piece of history, makes no mention of any method of salvaging the Hubble with or with out the shuttle. It does not answer the question in any way, shape or form.

This you might find just as interesting.

http://www.deepastronomy.com/how-the-hubble-space-telescope-will-die-video.html

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Human endeavour.

Human endeavour is a wonderful thing, but your reply is still pointless and meaningless in the context of the question asked.. There is no spacecraft currently in service or planned which is capable of salvaging the Hubble for spare parts. Even if there was, what would be the point. At a quarter of a century old it's components will be mostly obsolete, so you would be spending hundreds of millions of dollars to retrieve components that could be built better and more cheaply on Earth.

When I said it was interesting I was being polite. I would be more interested if it was more on topic to be honest.

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Human endeavour is a wonderful thing, but your reply is still pointless and meaningless in the context of the question asked.. There is no spacecraft currently in service or planned which is capable of salvaging the Hubble for spare parts. Even if there was, what would be the point. At a quarter of a century old it's components will be mostly obsolete, so you would be spending hundreds of millions of dollars to retrieve components that could be built better and more cheaply on Earth.

When I said it was interesting I was being polite. I would be more interested if it was more on topic to be honest.

I find it more interesting when your not so polite. Did you just not bother at all to watch the video or read the transcript? It is far from science fiction what nasa has in store for the hubbles re entry to earth.

The point is that there is facillity to robotically move its orbit. Why not move it into a lunar orbit, keep it in the lunar shadow, perhaps and inch out more of its lifes capabilities? Cost wise it may not make much sense, but even so there are people who would welcome its safe retrieval to earth if only for sentimental value.

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Posted (edited)

The point is that there is facillity to robotically move its orbit. Why not move it into a lunar orbit, keep it in the lunar shadow, perhaps and inch out more of its lifes capabilities? Cost wise it may not make much sense, but even so there are people who would welcome its safe retrieval to earth if only for sentimental value.

So we can add orbital mechanics to the ever increasing list of scientific concepts you don't understand.

I will try and explain this simply so that hopefully you can understand this.

Using robotic means to de-orbit Hubble requires reducing Hubble's velocity by a very small amount, orbiting at a velocity of about 28,000 kph kph a reduction of just 300 kph is sufficient. This drops the lowest point of Hubble's orbit into the upper atmosphere.

The upper atmosphere, unlike space, is dense enough to cause friction. This friction decelerates Hubble further and heats it up in the process, causing it to burn up.

So all this robotic system is doing is decelerating Hubble by 300 kph, the atmosphere does the rest.

Now what you want to do is send it to the Moon. The reason you want to send Hubble to the Moon makes no logical sense, but neither does anything else you've said, so I'll simply ignore that.

To send a spacecraft to the Moon you need to accelerate it to a sufficient velocity to break free of Earth's gravity. This velocity is 40,320 kph. Hubble is orbiting at 28,000 kph, so you would need to accelerate by over 12,000 kph.

Are you beginning to see the problem yet?

Accelerating Hubble to escape velocity means making a change in it's velocity forty times greater than de-orbiting it. This would require more fuel... much more fuel. This means we need a much more massive robotic vehicle. But a much more massive vehicle requires even more fuel to move it's own mass.

But it gets worse.

If we just launch Hubble in the direction of the Moon it will simply pass around it and head back towards Earth. This is known as a free return trajectory. Once it gets to the moon we need to decelerate it to lunar orbital velocity, which is about 3,700 kph. So this requires yet more fuel.

So why not send it to the Moon instead of de-orbiting it(apart from it being a totally pointless exercise)? Because instead of using a small robotic vehicle to do the job you would need a bloody enormous, prohibitively expensive one.

So having explained all this to you (although I'm guessing that I've wasted my time) I come back to what you originally said, which was:

Maybe parts could be salvaged, i wonder if that would be possible to dismantle it even and piece it back to earth... Seems such a waste.

And my initial question, which you have dodged with totally irrelevant links:

How?

There was only one vehicle in history that could do that... the space shuttle. In case you missed it, the space shuttle is no longer in service.

To be honest, I'm not going to hold my breath waiting for a sensible or relevant answer.

Edited by Waspie_Dwarf
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A better solution in that case would be to let the hubble burn and send a totally modern telescope to the moon.

Hopefully future telescopes could also be part shuttle, capable of re entry and re launching. Better to wait and see where the money takes us.

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A better solution in that case would be to let the hubble burn and send a totally modern telescope to the moon.

Hopefully future telescopes could also be part shuttle, capable of re entry and re launching. Better to wait and see where the money takes us.

Why would we want to bring back space telescopes and re-launch them? We don't even re-use old telescopes already here on Earth! Far more efficient to just build new telescopes and launch them.

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I wonder if the tech has improved enough to send a much smaller version of the Hubble into orbit to continue the amazing discoveries? I assume that the limiting factor is still the size of the mirror, I've always understood bigger is better here for gathering very low light intensities. I know that with computer imaging they are getting quite good at removing or limiting atmospheric interference with ground based telescopes, but it's hard to beat the vacuum of space for clarity. It will be a very sad day when Hubble crashes to Earth.

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I wonder if the tech has improved enough to send a much smaller version of the Hubble into orbit to continue the amazing discoveries? I assume that the limiting factor is still the size of the mirror, I've always understood bigger is better here for gathering very low light intensities. I know that with computer imaging they are getting quite good at removing or limiting atmospheric interference with ground based telescopes, but it's hard to beat the vacuum of space for clarity. It will be a very sad day when Hubble crashes to Earth.

The tech has improved, and we are sending up the James Webb Space telescope which will replace the Hubble. It is not a visible light telescope, but still it will reveal amazing things.

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I wonder if the tech has improved enough to send a much smaller version of the Hubble into orbit to continue the amazing discoveries? I assume that the limiting factor is still the size of the mirror, I've always understood bigger is better here for gathering very low light intensities. I know that with computer imaging they are getting quite good at removing or limiting atmospheric interference with ground based telescopes, but it's hard to beat the vacuum of space for clarity. It will be a very sad day when Hubble crashes to Earth.

You are correct in saying that bigger is better. As Einsteinium has said the tech has improved, allowing a much bigger space telescope the James Webb Space Telescope, to be built (it's due to be launched in 2018). Hubble had a primary mirror with a diameter of 2.4 m, Webb will have an 18 segment mirror with an effective diameter of 6.5 m.

The reason Hubble was such an improvement over ground based telescopes was simply because it was above the atmosphere. That atmosphere is constantly moving, distorting the images that are received and hence limiting the resolution that ground based telescopes can achieve.

In the years since Hubble was launched the electronic detectors on telescopes have advanced incredibly, meaning that modern CCD are getting very close to being as good as they can possibly be. Hubble was not left behind with these advances. The fact that it was serviceable by the shuttle means that it's instruments have been updated during it's life time.

However things have moved on in other ways. Modern telescopes use something called adaptive optics. these working in various ways but basically some part of the telescope's optics are moved rapidly to counter-act the distortion of the atmosphere. The result is that ground based telescopes are now matching or surpassing the capabilities of the Hubble.

Given the advancement of adaptive optics, a smaller version of Hubble would be far less capable than current ground based telescopes... and orders of magnitude less capable than the three new generation mega-telescopes (the Giant Magellan Telescope, the Thirty Meter Telescope and the European Extremely Large Telescope) currently being constructed. Even the Webb can not compete with these.

This is why the Webb will not be looking at the wavelengths visible to the human eye. Instead it will be looking at the near and mid infra-red wavelengths. These are absorbed by the atmosphere, so the Webb will be capable of seeing things that even the largest ground based telescopes can't.

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You are correct in saying that bigger is better. As Einsteinium has said the tech has improved, allowing a much bigger space telescope the James Webb Space Telescope, to be built (it's due to be launched in 2018). Hubble had a primary mirror with a diameter of 2.4 m, Webb will have an 18 segment mirror with an effective diameter of 6.5 m.

The reason Hubble was such an improvement over ground based telescopes was simply because it was above the atmosphere. That atmosphere is constantly moving, distorting the images that are received and hence limiting the resolution that ground based telescopes can achieve.

In the years since Hubble was launched the electronic detectors on telescopes have advanced incredibly, meaning that modern CCD are getting very close to being as good as they can possibly be. Hubble was not left behind with these advances. The fact that it was serviceable by the shuttle means that it's instruments have been updated during it's life time.

However things have moved on in other ways. Modern telescopes use something called adaptive optics. these working in various ways but basically some part of the telescope's optics are moved rapidly to counter-act the distortion of the atmosphere. The result is that ground based telescopes are now matching or surpassing the capabilities of the Hubble.

Given the advancement of adaptive optics, a smaller version of Hubble would be far less capable than current ground based telescopes... and orders of magnitude less capable than the three new generation mega-telescopes (the Giant Magellan Telescope, the Thirty Meter Telescope and the European Extremely Large Telescope) currently being constructed. Even the Webb can not compete with these.

This is why the Webb will not be looking at the wavelengths visible to the human eye. Instead it will be looking at the near and mid infra-red wavelengths. These are absorbed by the atmosphere, so the Webb will be capable of seeing things that even the largest ground based telescopes can't.

Good to see new generations of telescopes will be coming online, can't wait to see the images.

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Posted (edited)

Good to see new generations of telescopes will be coming online, can't wait to see the images.

Yes it will be interesting to see how they surpass hubbles imaging. Whether it be whales or Private Ryan, sometimes somethings are worth saving and the hubble is no exception. Have you seen this doco sundew?

Saving Hubble, a new independent documentary film, examines NASAs decision in 2004 to cancel the famed Hubble Space Telescope and introduces us to the people who united to save it. Many films have been made about Hubble and its many accomplishments. This is the first time a film about Hubble asks the question What does this machine say about us? Saving Hubble is the story of ordinary people finding a voice and a love letter to the machine that stands as humanity’s ambassador to the expanding universe.

http://vimeo.com/84731091

One thing I found it interesting how robotics could conceivably replace the shuttle service and repair schedule. I think even with the ground based telescopes the space hubble is far from obsolete as the OP clearly shows. The john Webb is a power of one but if the hubble was saved who knows what could be imaged by their power combined?

Edited by taniwha

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Posted (edited)

Whether it be whales or Private Ryan, sometimes somethings are worth saving and the hubble is no exception. Have you seen this doco sundew?

Sadly this thread is no longer one of those things worth saving.

I would ask why you want to spend billions to save a satellite that has already exceeded it's design life and is close to being obsolete, when those billions could be spent on new, better missions?

I would ask, but experience suggests that I will not get a straight answer from you.

Edited by Waspie_Dwarf

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