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Herschel Space Telescope Opens For the First Time 84
davecl writes "The Herschel space telescope, the largest ever launched into space, has opened its instrument cover, allowing its three instruments to observe for the first time. BBC news has the main coverage, while there is more coverage on the SPIRE instrument team website, and on the mission blog. I'm part of the SPIRE instrument team and the excitement as we move towards our first observations is building fast. The PACS and SPIRE instruments will see first light in the next few days."
space telescope (Score:5, Insightful)
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Maybe it'll be sensitive enough to image extrasolar planets.
From what I understand, even Hubble was sensitive enough to get a glimps of a few. Surely this will grant us an even better view. *Holds breath*
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We don't need any extra solar planets! We have enough solar planets as it is, especially if you count all them newfangled "dwarf" planets like Pluto and Grumpy and Sneezy. When I was a boy we only had eight solar planets, and we were happy to have them... (except maybe the one name after "yer anus")...
it is not the "largest evel launched into space" (Score:5, Informative)
The entry should clarify that it is the largest infrared telescope ever launched. Actually, the adjective large should not be used. Space is not porn. To most people.
It would also be very helpful for the public to know how will Herschel and Hubble complement each-other. Otherwise, the general public may believe that humanity has launched two different things to accomplish the same task.
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With the dwindling funds that space programs are receiving these days, it is a wonder that we can even send probes into space any more.
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I'm not sure who "we" is here, but note that it is mostly a European project, not a US one. It's good to see more international missions because it means more science and different ways of approaching designs and management. Russia's Keep-It-Simple and incremental improvement approach to manned-mission designs have been a fine lesson for NASA, for example. Hopefully NASA wil
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Now who's being ethnocentric?
I assumed GP meant "we" as in "humanity". Of course, now some asshat will accuse me of speciesism.
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Or singularists accusing you of pro-pluralist bias. Can't win :-)
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Re:it is not the "largest evel launched into space (Score:5, Interesting)
Re:it is not the "largest evel launched into space (Score:5, Informative)
Good reasons for placing infrared telescopes into space include the high opacity of the Earth's atmosphere in the infrared, the high thermal emissivity of the Earth and atmosphere in the infrared, and the low temperatures at which the detectors need to be kept.
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It's all optical, from 200 nm to 2000 nm.
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Why do they make Hubble and Herschel sensitive to infrared light? I would think it most important to pick a spectrum that will provide the best information...
Exactly. What spectrum you pick depends on what information you want to get.
Infrared is good for a lot of things. Dust clouds are mostly transparent to infrared, for example, so the infrared is good if you want to look, say, at the nuclei of galaxies (such as our own galaxy) which are surrounded by dust. And if you want to look at galaxies at high redshifts, which is to say, far away (and hence far back in time), infrared is good because the light is shifted into the infrared. Infrared is good at looki
Re:it is not the "largest evel launched into space (Score:5, Informative)
There is no one "right" spectrum frequency. They each offer different information; different clues. For example, an animal that can see 3 colors has more potential information than an animal that can only see 1 or 2.
And while Hubble and Herschel may be able to overlap somewhat, they are specialized (optimized) for different frequencies. It's difficult to make a single scope that can see every frequency well, so they send up different scopes for different spectrum ranges. Different materials make for better reflectors, conduits, and sensors for different frequencies. That's just life on the Spectrum Highway.
Think how AM radios need a long wire (coiled in practice) for an antenna. FM radios and traditional TV need about a meter-long antenna(s), and cell-phones have about a 3-inch antenna. No single antenna works best for all. Same with light-based scopes.
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"Same with light-based scopes."
Not to be pedantic, but all electromagnetic radiation is light, just not the way we're use to hearing it used.
Infra-red light is still light. 802.11 radiation is still electromagnetic radiation. Whether it's an AM radio in an old car, a $400 cell phone, or a telescope in the sky, it's all the same medium.
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I am not sure if "light" has a technical definition. Generally when one says "light", they mean either the visible spectrum (to humans), or frequencies close to it. That's what common usage dictates.
Re:it is not the "largest evel launched into space (Score:5, Insightful)
The atmosphere is a lovely IR absorber. So, if you're gonna launch a telescope into space, why not look at a band of frequencies you can't see thru the atmosphere? Whatever you see, it'll be something you can't see from the ground (more or less).
So that works pretty well, if the criteria is to see whats never been seen before, discover new things, etc.
http://en.wikipedia.org/wiki/Infrared_astronomy [wikipedia.org]
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"Largest" is simply poorly qualified. There's lots of different metrics that they could be referencing, such as weight (of the whole probe), aperture of light-gathering reflector/lens, and total energy of light/radiation it's able to collect and/or process per unit of time from a typical or reference target. Dollars/Euros spent also, for that matter.
Re:it is not the "largest evel launched into space (Score:2)
The entry should clarify that it is the largest infrared telescope ever launched.
...and perhaps also that there may well be larger telescopes looking down than up.
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It is actually the largest telescope every launched into space. It has a larger mirror than Hubble. It is also true that it is the largest infrared telescope launched into space, but then a square is also a rectangle.
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Actually measuring the aperture in wavelengths of light observed by the instrument might be even more meaning full; an instrument like Herschel that observes in the deep infrared need a larger aperture than Hubble to get the same resolution.
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According to Wikipedia [wikipedia.org]:
At 3.5 meters wide, its telescope incorporates the largest mirror ever deployed in space.
It's also important to note that there are fields other than porn in which size matters. In this case, the size of the mirrors in a telescope is proportional to the quantity of light it can focus to its sensors, and thus proportional to its sensitivity.
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The entry should clarify that it is the largest infrared telescope ever launched. Actually, the adjective large should not be used. Space is not porn. To most people.
The kid's never seen an an open elliptical galaxy. Heh.
Repair? (Score:4, Interesting)
I wonder if they designed any of it to be repaired in space, learning from Hubble. (It's not a direct competitor to Hubble because it "sees" in longer wavelengths.)
I wonder if it would have been cheaper to build *multiple* Hubbles rather than repair them in space, which costs about a half-billion per mission. However, they'd have to decide that path in advanced to take advantage of bulk assembly procedures. Or build them to be remotely serviceable thru a repair-bot? But that's mostly untried technology, which usually means expensive or unpredictable overrun risk.
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It's not repairable. It'll orbit around L2 and is placed 1.5 millions km away from earth. We cannot currently send humans at that distance. As for repairbots, I don't know.
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Such may be a good test-run for a Mars mission, killing 2 birds with one stone (for lack of a nicer saying). After all, before Apollo 11 actually landed, earlier missions went around the back of the moon in a partial test run.
Re:Repair? (Score:5, Informative)
The upside of it being in orbit around L2 is that it never has to face either the earth or the sun, so every second of every day is useful observation time. Hubble is in LEO which makes it accessible, but also shielded by the bulk of the planet almost half of every day for any given target. This is fine for scheduled observations, but not so good for staring at one point or homing in on something in progress. Also, some time is inevitably lost making sure it doesn't stare into something bright as it swings around the planet, which is not an issue at L2.
Even if it does not live as long as Hubble (and it probably won't if there is no servicing), it has the potential to produce more data per unit of time. Also, with the bigger reflector, exposures should not take as long, also freeing it up to do more science. This also has the nice side effect of reducing the effects of thermal noise and cosmic rays, since they just don't have as much time to do their damage to any given picture.
Mal-2
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It will live three to five years, so it will not outlive Hubble. After that it has run out of the coolant (helium).
By that time it has scanned the whole space a couple of times.
Re:Repair? (Score:4, Funny)
I agree. We should also have manned missions be one way as well.
Why pay a few million extra to bring them down again when we have 6 billion cheaply made replacements already available?
I hear the Chinese are itching to get to the moon, they could use the same plan. They could even pretend that they retrieved the astronaut. All they have to do is threaten to run over anyone who said differently with a tank.
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There's a handful of ex-politicians I'd like to volunteer :-)
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ex-politicians??
I have more than a handful of current ones I'd like to volunteer... from multiple countries, including my own.
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Too many and they may start a new colony and reproduce.
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The detectors, cameras and other instrumentation would come in a close second while the structure, power, navigation, and communications systems are probably largely built of off the shelf stuff.
Cameras and instruments get better and more sensitive, other systems require periodic maintenance and repair while good optics generally stay good provided they aren't physically damaged.
I would thi
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There is a risk of premature breakdown, but the cost of the Hubble is such that they've launched several groundbreaking, science advancing telescopes since Hubble, each did their intended job for less than the cost of a servicing mission via the manned shuttle.
Developing robotic servicing capabilities would be interesting, but that may be a ways off yet, and it's hard to design for something that hasn't been established yet, and designing for serviceability might also lead to compromises to the capabilities
Re:Repair? (Score:4, Interesting)
I wonder if it would have been cheaper to build *multiple* Hubbles rather than repair them in space, which costs about a half-billion per mission.
The Hubble repair cost was actually well over $1 billion. Even ignoring mass-production, it would have been cheaper to just replace the Hubble instead of repairing it. Let me dig up an old comment of mine from 4 years ago:
http://science.slashdot.org/comments.pl?sid=141507&cid=11856177 [slashdot.org]
An international team led by Johns Hopkins University astronomers have proposed an alternative [spaceref.com] to sending a robotic or manned repair mission to the ailing Hubble Space Telescope [wikipedia.org]. Their proposal is to build a new Hubble Origins Probe [jhu.edu], reusing the Hubble design but using lighter and more cost-effective technologies. The probe would include instruments currently waiting to be installed on Hubble, as well as a Japanese-built imager which 'will allow scientists to map the heavens more than 20 times faster than even a refurbished Hubble Space Telescope could.' It would take an estimated 65 months and $1 billion to build and launch, approximately the same cost as a robotic service mission.
Here's the official web site, with slideshows and posters explaining the planned scientific instruments:
http://www.pha.jhu.edu/hop/ [jhu.edu]
Lid Release Video (Score:2, Informative)
While not completely obvious from the wording, the slow motion video [youtube.com] that most sites seem to be using of the lid opening is actually from a test on an identical cover after it had been sealed for 2 years and not from the actual telescope in space. On the actual telescope, opening was only initially confirmed via gyro sensors and temperature changes afterwards. It won't be fully confirmed until they do light tests.
Except it has mysteriously stopped responding (Score:1)
Just as the Hubble happened to be flying by...
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Hubble is in low earth orbit. Herschel is en route to L2. They will be no flyby.
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Two telescopes in space... they needed a little privacy :)
Congrats to ESA and all involved! (Score:1)
I was really bummed when the Beagle rover went MIA years ago... so good for ESA, this is a great accomplishment!
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It was a static lander, not a rover. And it likely failed because they tried to do it on the cheap. Based on NASA's expenditure-versus-failure history, the amount they spent on it would result in very roughly a 70% chance of failure using the NASA scale. They got what they paid for, I hate to say. They should have scaled it down in my opinion. They got a little carried away with the features, havi
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The Beagle team knowingly skipped some landing-related tests to cut costs. Britain's own post analysis agreed with that. And my analysis is generally a statistical one. I agree the problem may have been related to something else: statistics only estimate probabilities, not guarantee them. If you plot failure-rate per expenditure for NASA probes, with some fudging for mission type and instrument count, it will generally point to what I said. (But I do agree its a small sample size one is using.)
Damn, pictures will be only tomorrow (Score:1)
Perhaps we should ask some Japanese to get some because today, it is tomorrow there.
How far out is 1.5 million miles? (Score:2)
I'm curious how far out this will be in comparison to Hubble. Is this in a Lagrange Point? The articles I'm finding via Google just note the distance but don't say much else about it.
Also, will the longer wavelengths give it a better chance of imaging through dust? What effect will it have on the images produced as opposed to Hubble?
Finally, given it's about a meter larger in diameter
Re:How far out is 1.5 million miles? (Score:5, Informative)
As pointed out earlier in a separated thread, Hubble is in a low, circular orbit about 560 km above the Earth. It has has a low inclination -- about 28 degrees with respect to the equator. You can actually see the orbital details and where it is in the sky on Heavens Above [heavens-above.com]. The low Earth orbit was chosen so that the space shuttles could service it as they can't reach very far orbits basically due to limitation i how much fuel they can carry (bear in mind that at launch the shuttle engines are powered by the huge orange tank attached to it). It would have to be double checked but I think that the low orbital inclination was decided because it's was easier to launch -- Hubble is one of the most massive payloads ever carried by a space shuttle -- since you benefit from the fact that the Earth rotates so it effectively adds up to your velocity whereas for a polar orbit the contribution is basically null.
On the other hand, Herschel is orbiting 1.5 million km away from the Earth at the L2 point, in a direction opposite to the Sun -- the Sun - Earth - Herschel system forms a straight line. To give you an idea of the scale, the Earth-Moon distance is about 385 000 km so Herschel is located 3.9 times further. Therefore it's easy to understand why the mission is a one-hit wonder because there is no way someone is gonna go there fix it. To be more precise, Herschel is actually "orbiting" about the L2 point (see this diagram [wikipedia.org] on Wikipedia) otherwise its orbit around the Sun-Earth-Moon system would be too unstable. The main reason for sending Herschel so far away from Earth is to optimize its infrared performances. Herschel observe at very long infrared wavelengths compared to, say, the the infrared camera of Hubble and near the Earth, even though you are in space, there is still a lot of thermal radiation coming from the Earth as well as the radiation belts that add up on top of what you want to detect. By being further away, passive cooling helps you and the liquid helium that keeps you cryostat cold heats up slower so your instrument has a longer life time. Also, "temperature" fluctuations are much smaller out there whereas they can be quite large near the Earth depending if your in the Earth shadow, crossing a radiation belt, etc. More stable environment means smaller systematics, which, in turns, imply better telescope sensitivity.
Finally, note that Hubble's successor, JWST will also hang out around L2 for similar reasons.
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Thank you
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Outgassing... (Score:3, Interesting)
But, don't the pyrotechnic bolts which held the hatch closed (which the article also mentions) outgas, and perhaps even send metallic fragments flying? There is obviously some explosive process involved.
I understand they're more reliable than mechanical latches, but given the need, wouldn't a solenoid operated latch have been better? The hatch would have held closed on its own until in space (since it contained a vacuum), and there's presumably not a lot of force needed to release the hatch once in space.
Re:Outgassing... (Score:4, Informative)
Manganese/barium chromate/lead chromate: time delay mix, used for sequencing. Gasless burning.
Zirconium/potassium perchlorate: NASA standard initiator (NSI). Rapid pressure rise, little gas but emits hot particles, thermally stable, vacuum stable, long shelf life. Sensitive to static electricity.
Which doesn't address the issue... (Score:2)
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I'm sure there's some good reason pal, you can find it out when you join the JPL. I do not know but it's a good question nonetheless.
I suppose that since this is /. (Score:2)
The Herschel was designed and built by the ESA [esa.int], not NASA and the JPL. JPL had nothing to do with it. [esa.int]
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Why in the world are you being so aggressive? I merely said the JPL because they are experts and would know the answer to your question. I read the damned article, I know Herschel is an ESA project, but guess who else uses explosive bolts?
Quit being a know it all, jackass. you don't.
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I understand they're more reliable than mechanical latches, but given the need, wouldn't a solenoid operated latch have been better?
That depends on if you want to be pretty damn sure it's going to open. The vast temperature differences tends to mock up most other methods. I think they where more worried about the thing not opening rather than some slight smear that might happen in bazzaro world which if it did occur could still be corrected for in software unlike the hatch being stuck shut forever.
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If you watch the video you'll notice a pronounced delay from when the bolts fire and the hatch opening, one fragment visible in the video leaves the area before the even begins to open.
isn't 1st light a traditional publicity point (Score:2)
am i the only curmudgeon who thinks telescope PR should start with 1st light ?
Cover opening doesn't actually mean anything is working - when they have images that are within spec being sent to earth on a regular basis, they have a working scope
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