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## NASA Considers Sending Telescope To the Outer Solar System152

Nancy_A writes "A mission that astronomers and cosmologists have only dreamed about — until now. A team at JPL and Caltech has been looking into the possibility of hitching an optical telescope to a survey spacecraft on a mission to the outer solar system. Light pollution in our inner solar system, from both the nearby glow of the Sun and the hazy zodiacal glow from dust ground up in the asteroid belt, has long stymied cosmologists looking for a clearer take on the early Universe."
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## NASA Considers Sending Telescope To the Outer Solar System

• #### Upwards? (Score:5, Interesting)

by Anonymous Coward on Tuesday December 20, 2011 @05:07AM (#38432226)

Why couldn't they just send one upwards out of the plane of the solar system? Wouldn't that be quicker?

• #### Earth's orbit and slingshots (Score:5, Informative)

on Tuesday December 20, 2011 @05:24AM (#38432302)

Why couldn't they just send one upwards out of the plane of the solar system? Wouldn't that be quicker?

Costs. And time.

We already have a certain velocity in the plane (earth is going around the sun, and we have to escape the sun's gravity well). We have practically zero velocity in the upwards direction. This is also who rockets are launched from near the equator.

Add to that possible slingshots around other planets, and you have your whole answer.

• #### Re: (Score:2)

But the relative velocity of the rocket, relative to Earth, is zero at liftoff, so our velocity relative the solar system's plane is not a factor that affects the rocket.

The slingshot around other planets can also happen in a perpendicular direction relative to our plane.

• #### Re: (Score:2)

If you want to get away from the Solar system, then ultimately the velocity relative to the sun is what matters.

True, you first need to get off the earth. And the speed relatively to the earth matters. But as you reach the right speed (11 km/s), soon enough the velocity relative to the sun starts to matter more. And then it was nice if our rocket took off in the direction of the motion of the earth, using all the earth's forward motion as a bonus.

• #### Re: (Score:2)

Where's the edit button? Sorry about the all italics.

• #### Re: (Score:2)

If there was an edit button, you could make an incredibly stupid remark, then change it making all the people who responded look like fools. Or you could make a good comment, and after it's moderated +5 you could change it to a GNAA Goatse troll. It would open up all sorts of trollery, and would be a very bad thing indeed.

That's what the preview button is for -- so you can edit.

• #### Re: (Score:2)

But the relative velocity of the rocket, relative to Earth, is zero at liftoff, so our velocity relative the solar system's plane is not a factor that affects the rocket.

On the other hand, the velocity of the rocket, relative to the Sun, is high at liftoff. And velocity relative to the Sun is the primary factor in determining the orbit, relative to the Sun, that a deep-space probe takes.

To provide some numbers, starting from LEO, a deltaV of around 6300 m/s would be about enough to get us to Jupiter using

• #### Re:Upwards? (Score:5, Insightful)

on Tuesday December 20, 2011 @05:25AM (#38432304)
They are probably going to use gravity assists [wikipedia.org], and planets are hard to come by outside of the ecliptic. However, I suppose they could use the last gravity assist to deflect it upwards.
• #### Re: (Score:2)

You could use the last gravity assist to deflect upwards, but what would be the point? If you've already used a few planetary passes working to build up significant velocity in one direction, why waste your last opportunity by adding velocity in a whole other direction? Most likely you're already past the asteroid belt by that point, and it won't help you get away from the sun's glare any quicker.

• #### Re: (Score:3)

It helps if you intend to overfly the poles of say, the Sun (Ulysses)...

• #### Re: (Score:2)

The orbit would require that the telescope go through the plane of the solar system twice each orbit, which if it is close to the sun would mean going through the dust.

The only way to beat this is to go a far away, which as other posters have said, is easier slong the plane of the solar system.

• #### Re: (Score:2)

Just like the planets tend to be in the same plane, so does the dust. However, at trans-neptunian distances, the orbital period is over 2 centuries. So even if the twice-an-orbit transit of the ecliptic plane took a year, it is still only 1% of the time.
• #### Re: (Score:2)

In addition to the points others have made, they want to be far from the sun so that it's not a significant contaminant. Whether you go out of the plane or stay in the plane you'll need to get to the same distance to do that. Also, they want to avoid the Zodiacal dust. Going a short way out of the plane means that the dust (and the sun) will be blocking large amounts of an entire hemisphere.

Also, probes going out to the outer reaches of the solar system can use gravitational slingshots to get extra speed. G

• #### Re: (Score:3)

Is the sun really a significant contaminant? I can see the dust being a problem, especially when illuminated by the sun...

On the other hand, if you're pointed away from the sun, without any significant dust in the way to reflect back the sun's light, I don't see how the sun would contaminate anything. I'm probably missing something...

• #### Re:Upwards? (Score:4, Informative)

on Tuesday December 20, 2011 @07:20AM (#38432830)

No, you're not, you're totally right - if you're pointing away from the sun then it doesn't contaminate anything. It depends where they're pointing it and what they're observing for whether it's an issue. You can mask out the sun but it will still be blocking a part of the sky - and more of it the nearer you are (obviously), and if you're any distance from it at all it will be many years before it gets out of the way.

The dust is probably more a problem though, I agree.

• #### Re: (Score:2)

Why couldn't they just send one upwards out of the plane of the solar system? Wouldn't that be quicker?

Because it would be whooshing through dust particles that orbit along the plane twice in its orbit, and it will get bashed up pretty quick.

• #### Re: (Score:2)

Why couldn't they just send one upwards out of the plane of the solar system? Wouldn't that be quicker?

The reason why is in the summary.

...Light pollution in our inner solar system...

If they were to go "upwards" they still have the light pollution. By going to the edge of our solar system, you got a lot of crap between you and the closets star (the sun), plus your farther away, which should give clearer pictures/images/whatevers.

I am, of course, a stoner and not some brainiac, but this answer i give seems like common sense to me. I could of course, be wrong, and if I am, then I learn something new. If i'm not, then woot! go common sense!

• #### Bandwidth make it improbable? (Score:5, Insightful)

on Tuesday December 20, 2011 @05:28AM (#38432316)
There is likely a bandwidth problem. Near-earth objects like Hubble and others can send us high-speed data streams. But while a distant telescope might see more, we would probably not be able to receive anywhere near the same data rate as for a closer object.

So... super-high resolution images at maybe one per day?

Maybe I have that wrong, but I don't think so. Higher-frequency (and therefore higher bandwidth) signals tend to attenuate more rapidly than lower-frequency signals do.
• #### Re:Bandwidth make it improbable? (Score:4, Interesting)

on Tuesday December 20, 2011 @05:58AM (#38432434)

Maybe the smart thing to do is have the 'scope do the data processing for us. In astronomy there's a lot of preprocessing from a large volume of redundant data to a small volume of high-value data, why not have a telescope that's got the intelligence (constantly updated and amended from Earth) to do some of that work before transmission.

• #### Re: (Score:3)

The solar system is mostly empty, what would attenuate the signal? The signal would have to pass through the dust causing the aforementioned zodiacal light, but I'm guessing that would not be enough to be a significant problem.

• #### Re: (Score:2)

It's hard to make a directional antenna that focusses all the energy into a few hundredths of a degree of solid angle.
• #### Re:Bandwidth make it improbable? (Score:4, Informative)

<hackertourist@x[ ]et.nl ['msn' in gap]> on Tuesday December 20, 2011 @12:02PM (#38436394)

Distance is the main factor. By the time you're far enough away, you need really big antennas (the Deep Space Network) of which there aren't many; you don't want to keep one of the few DSN antennas pointed at this probe 24/7.
On the transmitter side, the power and size/weight budgets limit the signal strength.

• #### Re: (Score:2)

The probe is only supposed to be sent out as far as Jupiter. That's pretty far, but NASA communicates with probes further out then that all the time.

• #### Re: (Score:2)

It's called "Free Space Loss" Even with a directional antenna, your signal is still subject to the inverse square law. As such, even though there isn't actually atennuation of any kind in a free space, your signal still drops markedly over a long distance. Between the surface of the earth and a satellite in geo-synchronous orbit (such as the DirecTV satellites, which is a hell of a lot of bandwidth) there is about 220dB of free-space loss. This isn't caused by atmospherics, it's just the drop-off due to d

• #### Re: (Score:2)

Not only this but the energy to broadcast the signal so far might be hard to come by without sunlight
• #### Re: (Score:2)

Probes beyond Jupiter are nuclear powered, so lack of sunlight is no issue.
• #### hmmm... (Score:2)

...far side of Pluto? There was a drama-docu sci-fi thing made by the BBC ("Space Odyssey: Voyage To The Planets" I think it was called) where part of the Grand Manned Tour was to install an optical array on Pluto. Shockingly good idea, I wonder why this hasn't been done yet (apart from the obvious being cost and how to remotely soft land not just one but a series of probes carrying precision optical instruments on a rock six billion miles away *and* get them synchronised *and* hope that the journey hasn't

• #### Re: (Score:2)

Too far, the best place to set one up, so we could learn from the building and apply that knowledge to future projects, would be to build one on the dark side of the moon and use a sat in orbit of the moon to relay the data to earth. While we were there we could do some small scale mining of H3 and see how feasible it would be to set up a mining operation.

Remember for anything in space you really need to start with baby steps and work your way up. After all we didn't just shoot some guys to the moon, we

• #### Re: (Score:2)

WE could have though. the Apollo program system was designed before the first launch, the orbital stuff was just making sure we did not end up killing astronauts on the first try and horrifying all of america. we could have easily landed on the moon with apollo 1, no testing, just go.

everything from apollo 1 to 11 was safety testing.

• #### Nah (Score:2)

we could have easily landed on the moon with Apollo 1, no testing, just go.

Although development of the LEM wasn't ready until Apollo 5 [wikipedia.org] (22 January 1968). The LEM was on the critical path for the Apollo program.

• #### Re: (Score:2)

And Apollo I isn't really a good example. I had nightmares about that when I was a kid.

http://en.wikipedia.org/wiki/File:Apollo_1_fire.jpg [wikipedia.org]

• #### Re: (Score:2)

Yeah. My dad came home shattered, like his own parents had died. Stared at the walls.

• #### Re: (Score:2)

As we learned from the shuttle disasters the American public simply doesn't have the stomach for killing astronauts which is why i wouldn't be surprised if China or India are the next ones out there...

I've always thought this was the best argument for non-governmental space exploration and exploitation. If the American public has lost its balls, fuck 'em -- the pussies can butt out. Let those who are willing to take the risks, the ones with the right stuff, reap the rewards.

• #### Re: (Score:2)

And again, looking at history, the expeditions to the north poll that were funded by government had a much higher failure rate than those funded by private enterprise.

• #### Re: (Score:2)

Ya know, I think that is what actually killed space exploration right there. To rip off a line from Right Stuff "Folks want Buck Rogers" and we started sending school teachers and math nerds. Glenn, Lovell, these guys had big fucking brass balls. I mean have you ever listened to the actual "Houston we've had a problem" recordings? I mean the guy is pretty damned calm when you consider half his damned ship just blew away. Hell I bet they could get a good 100 test pilot volunteers for a trip to Mars even if t

• #### Re: (Score:2)

would be to build one on the dark side of the moon

There is no "dark side" of the moon. The side that faces away from Earth is illuminated by the Sun just as often as the side facing Earth.

• #### Re: (Score:2)

until the Russians took photographs of it, it was known as the Dark Side. Orbital mechanics be damned.

• #### Re: (Score:2)

There's no good reason to put such a telescope on anything.

• #### Sure if you want to go smalltime (Score:2)

I mean, if you really want to rock some low light pollution just send it out of the galaxy.

Of course it'll take a few thousand years to get the data back from each picture, but what's a thousand years when you're looking at the beginning of the universe right?

• #### pilot (Score:2, Funny)

NASA Considers Sending Telescope To the Outer Solar System

I have an ex-wife I'd like to nominate to drive it.

Just tell her there's a Nordstrom's out there.

• #### IT saddens me... (Score:3)

on Tuesday December 20, 2011 @08:44AM (#38433540) Homepage

That we blow more money on a pointless war and other bullshit like bailing out the rich and the banks than doing real science and things that benefit all of mankind.

IF we were able to put a hubble telescope out around mars or even further out where it's a lot colder, we could really take advantage of things.

Instead we blow more than the entire NASA budge air conditioning tents for a war in a god forsaken land that will end up with another dictator within 10 years anyways.

• #### Re: (Score:3)

Instead we blow more than the entire NASA budge air conditioning tents for a war in a god forsaken land

There's plenty of room for debate, but many people believe that without protecting its own interests, the US would risk becoming one of those god forsaken lands. The risk might be small but nobody wants to take that chance.

• #### Send it farther, look at NEW Kepler targets! (Score:2)

News flash: NASA will announce something new (presumably more results) from the Kepler planet hunting spacecraft today.

Back to my post: if you can get it to about (I think) 500 AU, it gets to the focal point of the Sun's gravitational lens. The Sun then becomes a GIANT (as in millions of kilometers across) lens, allowing you to see at unbelievable resolutions even at distances of light years. I read somewhere it was at meters(?!) per light year, I can't believe that is true but even at KILOmeters per ligh

• #### Strap a booster rocket onto Hubble (Score:2)

Rather than let the crowning achievement of orbital optics burn up in the atmosphere, why not boost its orbit out of earth's neighborhood. Kick it up to a LaGrange point, or even further. Even if it floats in space until it runs out of batteries, it's still better than ending up as a ball of flaming metal in the upper atmosphere. And next century when spaceflight is commoditized, someone can salvage it and bring it back for a museum piece.

The Mars rovers have shown that useful science can be done far bey

• #### It's not about high-res piccies (Score:3)

on Tuesday December 20, 2011 @10:24AM (#38434910)

If you read the article, it's clear that this is intended to be an instrument which includes a very wide-field imager (3cm aperture) and a somewhat higher-spatial resolution (although that's only in a relative sense) channel with a 15cm aperture, both to operate in the optical/near-infrared. This is not about high spatial resolution imaging of the HST/JWST kind.

The aim is to detect the very faint extragalactic background light (EBL), which includes a component due to the integrated light from the first generation of galaxies in the Universe. Since the zodiacal light of the solar system drowns out that light, getting out beyond 5AU and thus beyond most of the asteroids which yield the dust which in turn reflect sunlight / emit their own IR flux, makes your telescope much more sensitive.

I would have said that this is just YAJS or Yet Another JPL Study, of which we've had several appear in these pages of late. If you want studies, I can give you loads of them: doesn't mean they're going to happen. And yet this one involves Chas Beichman and he knows what he's up to. It also very deliberately name checks the ESA JUICE (Jupiter Icy Moons Explorer) mission as a possible carrier for the proposed instrument package. OK, JUICE is also just a study at the moment, but within six months time, there's a 1-in-3 chance that it'll win the competition to be ESA's next L-class mission and thus much more "real".

Then again, given that JUICE's destination is the Jupiter system (duh), an EBL experiment would be limited to the cruise stage part en-route to 5AU.

Either way, a title of "NASA Considers Sending Telescope to the Outer Solar System" is pretty misleading: this is a study for an instrument package with a couple of cameras, photometers, and spectrometers which might hitchhike on another satellite; it scarcely qualifies as a "telescope" in the same sense as HST, Spitzer, Herschel, JWST, etc.

• #### NASA has had to cancel many probes (Score:3)

on Tuesday December 20, 2011 @11:09AM (#38435634)
Kepler turned out to be a roaring success with 2000 planet candidates so far and potential for 10,000 if the tea-party doesnt terminate it. You'd think that that two follow-ups to Kepler like the inferometric planet finder would be a sure bet. But both of these were shelved last year.
Ditto the Hubble telescope. It had a rocky start with the Challenger accident and mis-ground lens. But with a lot of jury-rigging t has been more successful, and costly, than most had anticipated. But its successor the Webb telescope is already triple budget and five years delayed. It came within a hairbreadth of being cancelled twice this year.

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