Successful Launch of ESA's Herschel and Planck 121
rgarbacz writes "Today at 13:12 GMT, the ESA launched successfully new and long-awaiting spacecraft: Herschel, the infrared telescope with a 3.5m mirror, and Planck, the CMB mapper. The spacecraft were carried by the Ariane-5, which lifted off from Kourou in French Guiana. They will stay in L2 to perform the research. This launch is one of the most expensive and important missions of the European Space Agency. Planck will measure the CMB with an accuracy more than 10 times better than the previous mission, WMAP. Because of this high sensitivity, both spacecraft are cooled to temperatures close to absolute zero by on-board liquid helium; staying in L2 is very helpful to maintain this state. Both spacecraft are designed to observe the Universe at its infancy: Herschel by observing the first stars and galaxies (whichever came first), and Planck by scrutinizing the first photons that were set free, making up the cosmic microwave background radiation."
with accuracy below 1% (Score:5, Funny)
SuperAccurate (Score:5, Insightful)
Planck will measure CMB with accuracy below 1%
Uhm. Is this technical terminology that I simply don't understand, or just a typo? Because I can understand a '1% margin of error', and I can sort of understand 'accurate to 1%'... but something which is below 1% accurate?
If only I could get away with that in my job.
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The bad news is that will be 9% accurate, followed by 9% accurate, followed by...
On the plus side, it'll still be nearly ten times better than this one.
Re:SuperAccurate (Score:4, Informative)
The correct term would be inaccuracy. Calling it accuracy is misleading, but very common.
Blame rgarbacz (Score:5, Informative)
It seems like the summary writer didn't understand TFA. Quoting from ESA:
The older measurements that Planck is trying to improve already are accurate to 0.1%.
It seems like someone got confused with the coincidence that the temperature of the universe, 2.7 K, is about 1% of the temperature of freezing water, 270 K.
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"(which is very cold, about 270C, near absolute zero)"
I think you dropped this: -
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(which is very cold, about 270C, near absolute zero).
Everything is relative of course, but I'm pretty sure with a minus sign it would be a lot closer: -270C.
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... Planck will examine this to a sensitivity, angular resolution and frequency range never achieved before.
I believe this 1% (+- 0.01) can be either the error level of one of the measurements or a general expression for an overall performance (not very scientific indeed). The commenter mentioned 10% (+- 0.1) for WMAP, and something around 40-50% (I do not remember exactly) for COBE.
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Can someone on this project tell us what took so long with Planck? I remember seeing a picture of it under construction in a cleanroom in the accompanying book to the PBS show "Stephen Hawking's Universe [youtube.com]"....... in 1998!
Re:SuperAccurate (Score:4, Insightful)
Most likely due to:
- funding (the launch phase costs the most because everything has to be tested & proven before it even goes up).
- other projects going up first (short-term projects slip in first etc), occupying launch events.
- feasibility (sometimes a great idea just is too risky)
in that order. it's not rocket science :)
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Probably waiting for Herschel to be finished so they could launched together.
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Sorry for a colloquial expression, it of course refers to the maximum error of the device.
What? (Score:2, Funny)
Accuracy below 1%? Did someone put a not gate in the wrong place?
Another Job well Done (Score:3, Interesting)
Between this and the fix ongoing on Hubble, where are set for some more time of great and impressive astronomy. Thank you NASA and ESA for keeping the good work.
Any one have any idea how they will keep the helium going on it? I tried on the articles but couldn't find the longevity and repair plans.
Re:Another Job well Done (Score:5, Informative)
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I realize we, as in all space agencies, use helium or something else to keep these instruments cold, but why can't we use the coldness of space to do the same thing? Isn't there some way to use one or more of the three forms of heat transfer to keep the instruments cold enough to work without having to rely on a limited source of helium?
Re:Another Job well Done (Score:5, Informative)
Well, that's because the space is too hot.
Even without the sun.
They are trying to measure the CMB. If you are not colder than outer space, most of the radiation would just come from the telescope itself...
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Well, that's because the space is too hot.
Huh? How can space have a temperature?
Re:Another Job well Done (Score:4, Informative)
If you have a distractor (radiation from the craft itself) as big as the thing you're trying to measure, you won't get good results.
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Space radiates. If we were to put a black body in space at absolute zero, after a while it would be about 2.7 Kelvin. This is because of the cosmic microwave background (which is what they're trying to measure here).
If you have a distractor (radiation from the craft itself) as big as the thing you're trying to measure, you won't get good results.
But emitting EM radiation isn't the same thing as having a temperature, is it?
I mean, I can see how the net effect is similar, because you still end up heating up your black block, similarly to what would happen if there was a heat transfer due to conduction.
It just sounds a little loose with terms to say that space has a temp.
Re:Another Job well Done (Score:5, Insightful)
To put it another way- heat is full of microwaves (the same as are in your kitchen appliance) which heats up everything in space to a certain point (2.7 Kelvin, if it's a black something). If you simply rely on "the coldness of space" to cool you down, that's as cool as you're going to get.
That's still EXTREMELY cold, but for this particular mission it's not cold enough. This mission is to measure said background radiation, meaning that in order to do it's job it must be colder than that extremely low temperature that is "the coldness of space".
Re:Another Job well Done (Score:5, Insightful)
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Well, you can with a fridge, which basically pumps the heat out of a confined space and heats the radiator grille on tha back, and you could in principle do the same for a satelite - in fact, I am pretty sure they do something similar to that in order to make the helium last for that long. But helium is pretty difficult to hold on to, it tends to leak out through any pressure seals, because it is comes as single atoms which are much smaller than even the two-atom molecules of hydrogen. And of course a cooli
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Re:Another Job well Done (Score:5, Informative)
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I found it after, but thanks for the link. Now let's put our science fiction minds to work and hypothize something (I'm sure the fellow slashdotters that know astronomy better than me will correct all the problems with my idea)
Since we are talking about L2, a place on space where the craft will be mainly stationary, isn't it feasible to make a "pit stop craft"? I mean, launch a craft that would stay at L2 and its only mission would be to fuel the other crafts in the region? What are the serious flaws in thi
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1) we're lazy
2) we're too busy spending money on new "gee whiz" human launch systems
3) then we're going to need a "tanker" to refuel the "pit stop craft". Next thing you know we have a whole infrastructure to support robotic space exploration/exploitation. It'd be far too practical.
Which L2? (Score:3, Interesting)
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Flaws? Well, for a start there's the fact that it's completely ridiculous...
Any fuel to be used for refueling would have to be launched with the craft - it all has to come from earth anyway so there's no benefit to be gained. It doesn't make any sense, it's just adding in an unnecessary layer of complication.
Even apart from that, a docking at the L2 point in order for the refueling would be a ridiculously complicated process - some kind of automatic system could be designed to do it, but (unless the craft's
Re:Another Job well Done (Score:4, Informative)
Because what they're trying to measure is, in some senses, the temperature of space itself - the ~3K CMB. So they need the detector to be colder than that.
Isn't there some way to use one or more of the three forms of heat transfer to keep the instruments cold enough to work without having to rely on a limited source of helium?
No. The radiative coolers (can't really use conduction or convection in space) will keep the craft cold enough for the low frequency instrument to work, even after the helium* runs out, but to get the 0.1K that the high frequency instrument needs, there's no (good) alternative to this active cooler.
* Well, not after the helium in its own refrigerators runs out. But it's not actively venting that, so we only have leakage to worry about there.
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to get the 0.1K that the high frequency instrument needs, there's no (good) alternative to this active cooler.
What about cooling lasers? I am not a physicist... although I aspire to be. Maybe someday I'll make friends with mathematics.
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Re:Another Job well Done (Score:4, Informative)
I realize we, as in all space agencies, use helium or something else to keep these instruments cold, but why can't we use the coldness of space to do the same thing?
Space isn't really "cold", or rather, the terms "cold" and "hot" lose much of their meaning when you're talking about incredibly low densities like you have in space.
If you have an atmosphere then you transfer heat by radiation and conduction. You can cool your instruments by putting them in the shade (so they don't get the radiated energy from the sun) and ensuring the atmosphere is cool so that it will conduct the heat away. The atmosphere on Earth is actually not a great conductor, but because it is a fluid you can keep the air moving so that as soon as some of the heat has been conducted to the surrounding air you move that (warmer) aid out of the way and replace it with cool air - this can be done naturally by convection or by forcing the air to move with a fan.
In space you have practically no atmosphere, so the heat transfer is almost entirely by radiation - your instruments are essentially in a giant vacuum flask. Your satellite needs to reflect away the energy radiated by the sun, and the cosmic microwave background radiation, etc. and also radiate away its own heat (remember, these satellites contain lots of electronics and like all electronics they will generate heat). This is a pretty tall order - surfaces that radiate well are also really good at absorbing energy. - I imagine it's much cheaper and lighter to send up a load of liquid helium and dissipate the heat by letting it boil away.
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I realize we, as in all space agencies, use helium or something else to keep these instruments cold, but why can't we use the coldness of space to do the same thing?
According to this PDF [nationalacademies.org] the Planck mission does not use liquid helium coolant (although Herschel does). Also the upcoming James Webb telescope will not use it.
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It's impossible to cool _and_ contain helium (which is superfluid at that temperature) within the limits of a small spacecraft.
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It's worth noting that Planck doesn't actually use a lot of liquid helium to cool itself down. It's cryogenic system is based upon "cryogen-free" mechanical refrigerators - the satellite launches warm, then cools itself down electrically and by radiating to space. The satellite lifetime isn't limited by running out of liquid helium.
Herschel, in contrast, does have a giant liquid helium tank. It launches full of helium, and eventually warms up when the tank runs out.
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During the launch commentary they mentioned that the scopes are launched with a 3 year supply of helium. I'm pretty sure repair missions to L2 would be pretty impractical.
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...and hilarious.
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Between this and the fix ongoing on Hubble, where are set for some more time of great and impressive astronomy. Thank you NASA and ESA for keeping the good work.
My thoughts exactly! I can't stop thinking the wonders they could achieve if they worked as a united force. Space science and exploration is really costly. Instead of pursuing different goals they should unite NASA, ESA, JAXA, and the Chinese "under one ring" and create a truly global team.
ISA anyone?!
telecope out on the range (Score:1, Funny)
Bout that telescope outside the second Lagrange point.
You know what I'm talkin' bout...
L2? (Score:3, Informative)
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Some sort of cache I think.
Re:L2? (Score:5, Informative)
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Wouldn't that quiescent point (of gravity between the earth and sun) be between the earth and sun, and therefore not in the Earth's shadow?
I thought the point was to keep it in the shadow - i.e. no solar radiation.
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Pretty amazing - it was cool to read about the asteroids in the L4 and L5 fields of other planets!
Thanks - BKG
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Also, at the L2 point, all three major heat sources (Sun, Earth, and Moon) are in the same direction. This allows them to have a single heat shield to block radiation from those sources, reducing the cooling needs. When you're trying to keep something at 1.5K, even the light shining off the moon can make a pretty big difference in how much it takes to maintain that temperature.
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Re:L2? (Score:5, Informative)
Lagrange point. Location where the gravitic pulls of some objects cancel each other out. In this case, it's Earth and Moon.
Re:L2? annular eclipse? (Score:2)
If the earth is 8000 miles in diameter, the L2 point 930,000 miles from earth, the sun is 870,000 miles in diameter, and 93,000,000 miles from earth, then the sun will subtend about .53 degree in the sky from the L2 point, and the earth will subtend about .49 degree. So -- the sun will be eclipsed by the earth, but it will be an annular eclipse -- even if the Hershel and Planck were right in the middle of the shadow, they would see a rim of sun all around the earth.
Is my math wrong? Or are these telescope
Re:L2? (Score:4, Informative)
Actually, it's the Earth and the Sun. It's on the Earth-Sun line, behind the earth (from the sun's point of view), and orbits the sun once a year. They put it here because it's easier to shield the satellite from both the Sun and Earth.
The L2 point for the Earth-Moon system is on the Earth-Moon line, behind the moon, and orbits the earth once evry 29.5 days.
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Lagrange point 2, one of the 5 locations in space around an orbiting body where the gravity wells from the major surrounding bodies cancel each other out, providing a sort of "still point" in space.
http://en.wikipedia.org/wiki/Lagrange_point
Ah how, how, how, how....
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http://en.wikipedia.org/wiki/L2_point [wikipedia.org]
FFS (Score:1, Informative)
Plural of "spacecraft" is "spacecraft".
English, do you speak it?
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"new and long awaiting spacecrafts....both spacecrafts are cooled...Both spacecrafts are designed"
Plural of "spacecraft" is "spacecraft".
English, do you speak it?
Actually Herschel and Planck are _two_ of the most expensive and important missions. But maybe we are being too hard on the author of this piece, who may not have english as his native language.
Indeed, the working language of ESA is something known as "franglais". It sounds like french and has grammar like french, but uses mostly english words. From experience, a communication like the article summary is actually pretty good by ESA standards...
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I don't blame the original author, but the incompetent editors who should have noticed and fixed it before publishing it.
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It's never too late to fix bugs in the language.
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please do not contribute this error to ESA - I do not work for this agency, I am just a space exploration enthusiast.
Don't worry, you'd fit right in...
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Plural of "spacecraft" is "spacecraft".
But the plural should be spacecreft!
Re:FFS (Score:5, Funny)
Plural of "spacecraft" is "spacecraft".
But the plural should be spacecreft!
Spacecruft?
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No, that's the stuff they have to scrape off the shuttle's windshield after each mission.
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Spacecruft?
no, that's past plural tense of "spacecraft"
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"new and long awaiting spacecrafts....both spacecrafts are cooled...Both spacecrafts are designed"
Plural of "spacecraft" is "spacecraft".
English, do you speak it?
Hmm, do you speak it?
Quoting 'Wiktionary':
Noun
Singular: spacecraft
Plural: spacecrafts or spacecraft
spacecraft (plural spacecrafts or spacecraft)
1. A vehicle that travels through space.
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Cite a real dictionary and I might take note. Any idiot can write a Wiktionary definition. I have, for instance.
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Quoting 'Wiktionary':
Any idiot can write a Wiktionary definition. I have, for instance.
An idiot like you? Well, you said it.
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I know it is not the most reliable source for English, but http://en.wiktionary.org/wiki/spacecraft [wiktionary.org] says that both forms are correct you may write spacecrafts as well as spacecraft.
By the way when all (or at least a large group) people who speak some sort of English start to use words differetly then this becomes the standard.
It is like the s indicating genitive case in German. For example it was "Toms Buchladen" (TomÂs Bookshop) and nowadays you can also write "Tom's Bookshop" which I find completely
Far out and still close to home... (Score:4, Interesting)
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Sounds like you are close to a Total Perspective Vortex.
http://fscked.org/writings/TotalPerspectiveVortex/ [fscked.org]
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But before I looked it up I had completely forgotten that Mars is at best still another 53 million km and then imagining the billions of lightyears Herschel will be able to "see"... I have to buy another ticket for "Star Trek" to lose this image of an invisibly tiny blue spec in a black void in my head...
Here's something that won't help you do it: http://www.physics.uci.edu/~observat/Physical_Scales.html [uci.edu]
Happy launching (Score:4, Interesting)
It's really awesome this thing launched succesfully. My professor of astronomy and his department worked ten years on Herschel. I'm really happy for him.
I hope the sattelite gives us a lot of useful information or at least some beautiful pictures
Re:Happy launching (Score:5, Funny)
it's all about the pretty sparkle isnt it?
If I don't get new desktops by June I will NOT be happy...
Free Software On Both (Score:5, Interesting)
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The NASA/GSFC Solar Dynamics Observatory (SDO) also uses RTEMS on some of its support processors. The main processor on SDO runs the closed source VX/Works OS.
Re:Free Software On Both (Score:4, Funny)
Nice site. Interesting project.
Its a good thing they didn't put (insert x86 architecture OS here) on them.
I can see the first message sent back containing the words "No keyboard present. Press F1 to continue." ... followed by a prolonged silence. ;)
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Well they are not mindless automatons. And they need stable OS which they can adapt to their needs. And their should be no usage restriction. So they only can use free OS.
Very well written submission! (Score:2)
UOA and WUVESDFA and very well employed in the article summary. They are great tactics to keep the reader guessing about WTF they are reading. Furthermore, overuse of hyperlinks is a big problem these days. A summary need link to nothing more than a single article, which no one will read anyway. Any other linking to clarify the meaning of the story is just wasteful. Lets hear it for more Unidentified Obscure Acronyms (UOA) and greater use of Wait Until the Very End of the Summary to Define the Fucking Acron
Launched by a bunch of skinheads? (Score:1)
Herschel and Planck? (Score:2, Interesting)
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Failure to understand that basic laws of physics (Score:2)
Okay, so at the point of the big bang, the entire universe was concentrated into a single point of matter.
At some point in the past the big bang occurred and matter and energy expanded from this single point at the speed of light or near it
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Okay, so at the point of the big bang, the entire universe was concentrated into a single point of matter.
At some point in the past the big bang occurred and matter and energy expanded from this single point at the speed of light or near it, as best we can tell. The matter and light were traveling away from the point of orgin, at the highest possible speed, the speed of light which we say is a constant and is the max attainable speed by anything, ever.
No you are wrong. Not the matter and energy traveled away from a point in space. The space expanded. I know the phrase "Big Bang" implies an explosion, but it was no explosion it was an expansion. An expansion of space. Therefore nothing traveled. And space can theoretically expand faster than the speed of light.
Golly... (Score:1)
Herschel and Planck? (Score:2)
At first I thought this was a new spinoff game release. However I'd expect the title to come from SCEA, not ESA.
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