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Construction of ESA Galaxy Mapping Satellite Completed

Unknown Lamer posted more than 3 years ago | from the beach-photos-with-a-zeta-reticulan dept.

Space 45

coondoggie writes with an article in Network World. From the article: "The European Space Agency says it has completed what it calls the largest digital camera ever built for a space mission — a one billion pixel array camera that will help create a three-dimensional picture of the Milky Way Galaxy. Set to be launched onboard the ESA's galaxy-mapping Gaia mission in 2013, the digital camera was 'mosaicked together from 106 separate electronic detectors.' ESA says that Gaia's measurements will be so accurate that, if it were on Earth, it could measure the thumbnails of a person on the Moon."

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Leo (2)

pablo_max (626328) | more than 3 years ago | (#36672942)

No, only if we could leave low Earth orbit and actually use said map.

Re:Leo (2)

djlemma (1053860) | more than 3 years ago | (#36673070)

If we were going somewhere that this satellite was trying to map, then I think leaving LEO would be one of the lesser challenges...

Thumbnails? (1)

boristdog (133725) | more than 3 years ago | (#36673000)

But could it measure a Library of Congress of Volkswagens full of ping-pong balls on an aircraft carrier?

Re:Thumbnails? (2)

blair1q (305137) | more than 3 years ago | (#36673298)

The moon is about 4e8 m away. A thumbnail is about 1e-2 m across. This telescope can resolve things 1e-10 in size relative to distance.

The center of the galaxy is 1e16 m away. 1e16 * 1e-10 = 1e6.

This telescope can directly image objects 1000 km across at the center of the galaxy.

May I just say, holy fuck!

Re:Thumbnails? (4, Insightful)

jpapon (1877296) | more than 3 years ago | (#36673646)

This telescope can directly image objects 1000 km across at the center of the galaxy.

Well, maybe, but that's assuming said object is really luminous. Sure, you can get 1000km resolution on a star, but it does you no good to have 1000km resolution on an exoplanet if the number of photons reaching you from the exoplanet are less than your noise floor. I could be wrong, but I don't think this resolution is *quite* as exciting as it sounds... unless of course you attach it to some wide aperture high quality optics.

Re:Thumbnails? (2)

djdanlib (732853) | more than 3 years ago | (#36675452)

Hooray for being someone who gets that.

Everyone goes ga-ga over the number of megapixels, while the professionals care about subject material and the sensor's dynamic range, gain characteristics and noise floor.

Re:Thumbnails? (0)

Anonymous Coward | more than 3 years ago | (#36677458)

Wouldn't this imply, however, that objects found at the galactic center (or equivalent distance) can be measured and rendered as something other than point sources of light?

I assume that one of the roles of this spacecraft is to increase the resolution of measuring stellar parallax. Some advances have already happened along that route, but any increase in the accuracy of those measurements, even if they don't quite meet the extremes suggested by this level of precision, certainly can be a huge benefit for improving astronomical yardsticks. Even measurements of a milliarcsecond have been outstanding as of a couple of decades or so ago.

From other sources [] apparently this telescope can measure down to the range of just a dozen microarcseconds. That is something to go ga-ga over that means a whole lot more than the "mega pixels" and is something which professionals do care about.

Re:Thumbnails? (1)

djdanlib (732853) | more than 3 years ago | (#36685840)

Remember, photons are photons whether they are reflected or traveling directly from a light source. There is no implication of their source. If you designed a satellite to observe celestial bodies, would you build it so it could observe sources and reflecting bodies? I would.

Spatial resolution is spatial resolution no matter what units you're using. You've still got to translate pixels to microarcseconds somehow - I'm sure that stellar parallax must still be derived from multiple measurements over time, which are now much finer with the new satellite. Yes, having a vast spatial resolution is excellent news!

When I'm talking about non-spatial resolutions, I'm mostly speaking in terms of how many photons are required to trigger the "Hey! There is a signal!" response of an individual sensing element. You can't measure zero photons, and it's not usually feasible to detect one photon - so how faint of a source can it detect? Fainter and fainter sources being detected could mean that we can directly observe planets that we had previously only calculated should exist.

I look forward to seeing some new images from this satellite!

Re:Thumbnails? (1)

Crookdotter (1297179) | more than 3 years ago | (#36673716)

That can't be right, surely. I mean, I'd expect such a camera to come across some sort of mega engineering projects if that were the case, and directly image many planets, which I thought was many years down the line? Or is it set up just for stellar observation with limitations that preclude what I'd just said?

Re:Thumbnails? (1)

blair1q (305137) | more than 3 years ago | (#36674110)

If you read TFA, they're going to be looking at everything. Stars, planets, intersolar freways, clear-cutting of the Rigel 7 rainforests. Every damn thing.

Yes, I expect to see pictures of exoplanets that look like backyard telescope pictures of Jupiter and Mars.

Re:Thumbnails? (0)

Anonymous Coward | more than 3 years ago | (#36673414)

Re:Thumbnails? (1)

Intron (870560) | more than 3 years ago | (#36674068)

But could it measure a Library of Congress of Volkswagens full of ping-pong balls on an aircraft carrier?

From the article:
Gaia's transmitter is weak, much less powerful than a standard 100 W light bulb.

You have left out the all-important light bulb unit.

NASA must be pissed (0)

Osgeld (1900440) | more than 3 years ago | (#36673064)

they didn't get to waste that money

Re:NASA must be pissed (1)

Jeng (926980) | more than 3 years ago | (#36673400)

Doubtful. NASA survives on a shoestring budget.

And as to why we were able to get to the moon, but can't now, remember that in the 60's in the middle of Vietnam, NASA had more funding than the DoD. Now NASA's budget is less than the cost of air conditioning for the DoD. And people still bitch and moan about how much NASA is spending.

Re:NASA must be pissed (1)

Lumpy (12016) | more than 3 years ago | (#36673460)

"And really stupid people still bitch and moan about how much NASA is spending."

Fixed that for you.

Re:NASA must be pissed (0)

Anonymous Coward | more than 3 years ago | (#36674896)

oh man really, we would never know how worms fuck in space without NASA, its a shame we cant that money for unworthy hot button items like education

but space worm porn it is! lets put another storage shed on the ISS! its for mankind!

Different century, same old stupidity: (2)

Hartree (191324) | more than 3 years ago | (#36675910)

Was your great grandpappy one of those who was laughing at the Wright brothers and saying "If man were meant to fly, he'd have wings."?

Or are you just a researcher whose proposal didn't get funded?

Re:NASA must be pissed (1)

JWSmythe (446288) | more than 3 years ago | (#36677952)

Nope, that's worthless. We should have taken from the small subset of the federal budget that is NASA, and given to the larger subset of the budget which is education, while ignoring the vast bottomless pits that money is thrown towards now.

    Education isn't purely funded by the federal government either. Schools have the luxury of being funded by states and local government also.

    How about this. In FY2010...

$18 billion went to NASA.
$150 billion went to education.
$685 billion went to the DoD.

    The DoD plans on spending $382 billion on the F-35 program, so we'll have the bigger badder fighter aircraft than anyone. Since we already hold air superiority and that's not being challenged, that could easily be deemed an unnecessary expense.

    So, why don't you show us where you would make budget cuts from, and not just preach from the "think of the children" handbook.

Re:NASA must be pissed (2)

JWSmythe (446288) | more than 3 years ago | (#36677048)

    Yup. There was someone ranting one day about how much NASA spends, so I took the time to go through the federal budget numbers, break it down, put it back together, and showed how insignificant the NASA budget was compared to other things that we really don't need and shouldn't be doing.

    Consider how much money has been put into new fighter aircraft, when there isn't an enemy with the capability of deploying aircraft to even get to CONUS. Some of the projects are dropped after spending billions, and not a single aircraft has made it to production. I could go on for hours about the DoD spending, and how it's not helpful in the least to the people of the United States. The government claims these wars we're fighting now are to help Americans, but there hasn't been a legitimate threat of war by any country against CONUS since WWII.

    Even during the cold war, the threats were inflated by both sides, and the military buildup existed as more of a show of force to their own citizens, than to scare the enemy. Instead of this huge wartime budget that we've been burying ourselves with, this could easily be peace time. That's only the financial side of it. The discussion of the lives of our soldiers, both in deaths and life changing effects could be nil, *AND* we could have had sizable research stations on the moon, Mars, and other objects in this solar system. Instead, we're looking at the last launch of the only American spacecraft capable of carrying humans on Friday morning. Our only fallback plan is the rough equivalent of selling your car, and hitching rides with your neighbors to get anywhere. That's particularly odd that we're now to depend on our cold war enemies to furnish our only way to space. We've forgiven them, but still have harsh sanctions against Cuba for housing a few Russian missiles decades ago, and sending them back to Russia years before most people reading this were ever born. That's November 1962, for those who may be wondering.

    How much is wasted continuing the nonsense against an enemy who hasn't done anything against us in almost 50 years?

Re:NASA must be pissed (1)

Daniel Dvorkin (106857) | more than 3 years ago | (#36675056)

Turn off your computer now. Also turn off your electricity and water, stop eating any foodstuffs not hunted (by hand) or gathered in the wild, take off any clothes you're wearing that aren't made from animal hides or woven grass, and go chip some tools out of flint. Actually, scratch that last part -- who needs to waste time on researching how to break perfectly good rocks when you can just pick them up and throw them at things? Be careful, though; you don't want the fire in your cave to go out, since it can be hard to find a new source.

Re:NASA must be pissed (1)

Osgeld (1900440) | more than 3 years ago | (#36677120)

computers existed before NASA by a number of years
foodstuffs not gathered in the wild is cultivation, and there are plenty of people who might lay claim to that before NASA
The Greeks had woven fabric, synthetic development was during WWII for military reasons
When you throw rocks at bigger rocks you break them, it might help your grasp on reality
and that fire bit is amusing considering a lot of people tend fires in their lives daily, whether its a pilot light for the furnace or a fire out side of a tent

Thanks NASA for computers, food cultivation, food canning/freezing, woven fabric, nylon fabric, physics, and fire!

Did we miss any?

Re:NASA must be pissed (1)

Daniel Dvorkin (106857) | more than 3 years ago | (#36677870)

Did we miss any?

In your case, what you're missing is the point, by a mile. This isn't about NASA. It's about the overall value of research, without which we would all still be living in caves and scratching bare-handed in the dirt. If you don't accept that, that's your privilege, but you should have the courage to act on your beliefs, which means GTFO of the modern world.

Re:NASA must be pissed (1)

Osgeld (1900440) | more than 3 years ago | (#36679560)

no, I am pretty sure I started the topic with NASA as the first acronym, please feel free to prove me wrong

Talk about bad timing (1)

zill (1690130) | more than 3 years ago | (#36673156)

In a related story, Transcenic Inc filed a patent infringement sue [] against Google, Microsoft, MapQuest, and AOL for allegedly violating their 3D mapping technology.

Guess who Transcenic Inc is targeting next?

Note: this is post is meant to be humorous. I realize that patent doesn't apply in this case. Not without the Chewbacca defense at least.

Re:Talk about bad timing (1)

blair1q (305137) | more than 3 years ago | (#36673308)

The Chewbacca defense has been obsoleted by the Evil Grandpa defense.

Could measure the thumbnails... (1)

P Nitram (2347806) | more than 3 years ago | (#36673160)

Can it take a picture of the American flag on the moon? I'm just curious to see if it's dirty.

Re:Could measure the thumbnails... (1)

damburger (981828) | more than 3 years ago | (#36675204)

Somehow, I think a camera designed to stare into the inky blackness of space is probably best not pointed at a fully illuminated part of the Moon's surface.

The likely final nail in the coffin of the Apollo hoaxes will be a photo of a bunch of Chinese astronauts standing around one of the descent modules.

Re:Could measure the thumbnails... (1)

geekoid (135745) | more than 3 years ago | (#36675984)

I would be surprised if the nylon hadn't completely disintegrated from the harsh and direct UV rays from the Sun.

Re:Could measure the thumbnails... (1)

JWSmythe (446288) | more than 3 years ago | (#36678310)

It may have, but with no wind (or atmosphere), and very little gravity, it probably wouldn't fall apart until something touched it.

It's so powerful (1)

Normal Dan (1053064) | more than 3 years ago | (#36673184)

if they pointed it back towards Earth, it could be used to spy on us.

Re:It's so powerful (1)

Infiniti2000 (1720222) | more than 3 years ago | (#36673230)

Nah, they'd never do that.

Re:It's so powerful (0)

Anonymous Coward | more than 3 years ago | (#36673518)

You have some egg on your tie.

I mean, yes, no, we--they! They would never do that.

Measuring your thumbnails from orbit (1)

billstewart (78916) | more than 3 years ago | (#36673784)

LEO is 500x closer than the moon. Nah, you're right, they'd never :-)

Realistically, other than the silliness of it (and the atmospheric distortion), the camera only has a billion pixels (and really great optics). If they're trying to focus in really great detail, they can't cover that many people or that much area at once. 1000 people would be a megapixel each (so wear your hats, folks), but if you were building a spy satellite instead of one intended for deep astronomy pixels, you could probably do a good job of tracking individuals moving around.

Camera finished, not satellite (5, Informative)

Trapezium Artist (919330) | more than 3 years ago | (#36673316)

To avoid any confusion, we have finished the assembly of the focal plane assembly (i.e. those 106 large CCDs), but not the full-up satellite itself. That still has a way to go, with launch likely at the end of 2012 or early 2013. But it's nevertheless a great achievement to have the huge detector array done and is a real milestone for us.

Also, Gaia isn't taking pretty pictures of the sky per se: via repeated scans over the sky, it's going to provide extremely accurate positions and velocities for about one billion stars in the Milky Way, allowing us to trace their motions back (and forward) in time, and thus understand how the Milky Way was put together in the first place. It does much, much more than that, so if you're interested, I suggest you follow the link in the original submission for more.

(DIsclosure: I work for ESA and am close to the project)

Re:Camera finished, not satellite (1)

Trapezium Artist (919330) | more than 3 years ago | (#36673558)

Apologies: too many "assembly"'s in the first sentence, but you get my drift, I hope :-)

Re:Camera finished, not satellite (1)

lazn (202878) | more than 3 years ago | (#36674684)

why did they do the CCDs first? Over the course of the next year those are the things most likely to improve from advancing technology..

Like building a hybrid car by starting with lead acid batteries and taking decades to build the chassis.. By that time Lithium Ions would be out. etc.

Re:Camera finished, not satellite (2)

Trapezium Artist (919330) | more than 3 years ago | (#36675194)

Not really; these are very specialised custom CCDs made for Gaia alone, to its specific requirements. Because of this, they're a very long lead item and need to be tested rigorously, which means that they needed to be done early. That said, most of the parts of Gaia are ready by now, and the remaining time before launch will be needed for integration and testing of the whole system.

While you're right about the rapid pace of detector development in the commercial sector, those are very different beasts to the ones needed for most scientific applications. For one thing, we almost exclusively use "black-and-white" detectors, i.e. which can image a single colour or single band at a time through a filter: we need this to ensure the highest sensitivity to faint sources. We can then make colour pictures later by superimposing images taken in several different bands. We also generally use very long exposures, so we need detectors which work at very low temperatures to avoid dark current noise. Finally, we can usually tolerate slightly imperfect detectors in terms of dead pixels, because we usually take a series of dithered images and can fill in the bad pixels later. On the other hand, we really care about low read noise.

Commercial detectors these days usually take colour pictures straight off, by having clusters of RGB pixels on chip. Cosmetic quality is at a premium, but dark current noise is less of an issue. Finally, they usually run warm, not at cryogenic temperatures. Many commercial imaging sensors are in fact CMOS devices now, whereas CCDs still pretty much rule the roost for optical imaging in astronomy. That said, I was approached at this week's UK Space Conference in Warwick by representatives from e2v, the suppliers of Gaia's CCDs, wanting to talk to me about scientific uses of their CMOS line :-)

Re:Camera finished, not satellite (1)

Hartree (191324) | more than 3 years ago | (#36676218)

"It does much, much more than that"

I've been watching Gaia's timeline for more than a decade. This mission is doing so many worthwhile things it's amazing. High resolution astrometry data for a billion stars.

Astrometry may not have the "pretty picture" allure of the Hubble or Webb telescopes, but it's in many ways even more important. Astronomers will be mining this data for a long time.

I remember the anticipation when Hipparcos launched and the chagrin when it didn't reach proper orbit. The ability to not only recover from that, but exceed the original aims of the mission was very impressive.

Imagine if it had really BIG mirrors! (2)

wisebabo (638845) | more than 3 years ago | (#36673596)

By the scale of the upcoming James Web Space Telescope or even by the Hubble Space Telescope, GAIA has some pretty small primary mirrors (1.45m). Hell, there are probably some amateurs with telescopes with bigger mirrors than that (though not 1.5 million kilometers in space!). I'm amazed that with such small mirrors it will have the sensitivity to do all that is claimed it will like find (hopefully) tens of thousands of brown dwarfs which are very dim (hence the name). (Of course ACCURACY not sensitivity is the main goal of this thing, that's why even though it could have the resolution to pinpoint a thumbnail on the moon it couldn't see it unless it was a very bright thumb!)

Still I am not a professional astronomer and since this is being done by the same(?) people as who created hipparcus, the previous spacecraft of this type, I'm optimistic that it will be equally successful. Someday we can hope here will be a version of this with really big mirrors, maybe that will allow us to get the remaining 99% of the galaxy. Still to think that soon we may have a pretty good 3D model of the galaxy (with a billion 3D data points) is amazing considering that the only comparable example of this was in Star Trek Voyager's "Map Room" set several centuries in the future! And they were still lost!

If one of the goals of astronomy is to show humanity's place in the universe, I think this goes a long way to fulfilling it. I really really want the 3D dataset when it comes out after 2018 so I can take my own virtual voyages through the milky way!

Re:Imagine if it had really BIG mirrors! (1)

kyle5t (1479639) | more than 3 years ago | (#36678130)

Hell, there are probably some amateurs with telescopes with bigger mirrors than that

I don't think so. The largest are Newtonians with a primary around 40".

More information on the CCD array (1)

hackertourist (2202674) | more than 3 years ago | (#36673740)

here []

LIkewise (0)

Anonymous Coward | more than 3 years ago | (#36674230)

... If it were on the moon, it could resolve a person's thumbnail, right?

Wasn't there just an article about adding a camera to the ISS?

Why aren't they putting more of these in space to tie in with their facial recognition programs? I want to be safe from terrorists, dammit!

if it were on Earth?? (0)

Anonymous Coward | more than 3 years ago | (#36675218)

What is the deal with that? Is it secretly being constructed at Utopia Planitia to be beamed back to Earth when completed? Just seemed like a funny way to express its resolution.

Article is wrong (1)

qinjuehang (1195139) | more than 3 years ago | (#36690810)

The resolution is 0.08 arcseconds. That translates to it being able to resolve 150m objects on the moon. You'd need a really big thumb I guess.

Re:Article is wrong (1)

Trapezium Artist (919330) | more than 3 years ago | (#36693104)

There's some confusion here. The raw image resolution provided by Gaia's mirrors is one thing and your estimate of 0.08 arcsec may be appropriate there.

On the other hand, Gaia's real job is to measure the position of stars very accurately, and that it can do down to a few microarcseconds: it doesn't resolve the stars, of course, but provides extremely accurate positions for them. By doing this repeatedly over several years, it can then see objects move by very small distances.

Ten microarcseconds at the distance the Moon is about 2 centimetres, so to be more accurate, Gaia could measure a movement as small as the width of a human thumb at the distance to the Moon.

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