Pluto

3488 · Sep 5, 2007

Also with Voyager, Voyager 1 was given a mandate, to get close & personal with the Saturn moon Titan. Voyager 1 approached Titan from the south & the trajectory past Titan meant that a wide swathe of latitudes were observable from close quarters. Problem was, if Voyager 1 took that option (which did happen), then firstly Voyager 1 was put on a trajectory that was far too north & secondly too fast to enable a Pluto encounter. Remeber back then, Titan was imaged by Pioneer 11 & Pioneer 11 clearly showed Titan to be a giant orange hazy ball. Voyager 1 was put on a trajectory, to see whether or not that haze, seen by Pioneer 11, had gaps or less opaque regions that the Voyager 1 cameras could see through to image at least some parts of the true surface of Titan. It was not too be. The haze was far too dense & it was global. If Voyager 1 failed the Titan encounter, than Voyager 2 was to carry out the same mission. Uranus & Neptune would have been sacrificed for Titan. Pluto already was the sacrifical lamb, no matter what happened. Voyager 1 was highly successful, so Voyager 2 was free to continue to Uranus & Neptune. Pluto back then, was considered an ice ball, with a large moon (Charon). Now we know that Pluto has at least three moons one large (Charon) & two small (Nix & Hydra) & that Pluto has seasons. Atmosphere forms, than freezes out. Also now we know that Pluto is but one of a whole class of objects that populate that region. Pluto was the largest know KBO until the discovery of Eris. Also 2005 FY9 & 2003 EL61 are also giant KBOs. Eris may be the largest & most massive, we do not know, perhaps there are some Mars or even Earth sized ones lurking around, waiting to be found. Pluto all of a sudden is not the big hit, it once was. Having said that, Pluto h <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MeteorWayne · Sep 5, 2007

Actually Charon was discovered long after the Voyagers were underway. Discovery date was 6/22/78. So they were halfway to Jupiter, which is the major gravity source to use for retargeting. V2 was launched 8/20/77, V1 9/5/77 (WOW today's the 30th anniversery!!!) V1 passed Jupiter 3/9/79, V2 7/9/79. So for the most part the die was cast in advance. It was too late to do any major retargeting, other than sacrificing science at Saturn for the opportunity to visit Uranus and Neptune for the first time with V2, once V1 made sucessful observations.. A wise choice was made. After V1's success with Titan at Saturn, V2 was targeted to pass both Uranus and Neptune, but that left it exiting the solar system on an inclined orbit "below" the solar system, the opposite of (by then) Pluto and Charon. Wayne <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Sep 5, 2007

Approx 50,360 KPH / 31,300 MPH. It will be a very short visit. Encounter diagram below. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

3488 · Sep 5, 2007

Sorry MeteorWayne, I was aware of that fact, but I was not clear. At the time of the Voyagers launches, Pluto was thought to be alone. I just wasn't clear. Even if Charon was known pre-launch, I doubt the decision would have changed thought. The die was cast for Voyager 1 to closely approach Titan & for Voyager 2 to go onto Uranus & Neptune, if the sister craft was successful. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

willpittenger · Sep 6, 2007

For those still scratching their heads on how to put a probe into orbit around Pluto, you might be a bit upset. Twenty years ago, I came up with a system to do just that. In fact, it was before I heard about the Magellan space probe and I was going to use that name for the first vehicle. I believe that I mentioned this concept in M&L a year ago. The concept was for a huge solar sail -- at least 5 miles across, possibly 20 miles. The main body of the craft would be at the center of the sail and it could retract the sail in increments. Please don't misread this. The craft itself would not be a space probe and would have few science instruments on board. Most would actually be things like navigation cameras. Rather, I created a ferry capable of making two-way trips. It could take a probe out to Pluto and then return. It could also go and pick up that probe at the end of its life for analysis and display in a museum. Imagine being able to retrieve Galileo for a postmortem. We could find out what happened to the tape recorder and that high gain antenna. There were limitations. First, due to the size of the sail and the amount of orbital debris, it could not risk approaching Earth if that could be avoided. Second, I assumed that the ferry would leave the ecliptic plane to cross the asteroid belt. Third, it might not have been able to retrieve Galileo, despite my implications above. I say that as it might not have enough radiation hardening. Galileo would have had to reach the outer Jovian system on its own. The numbers in the list below refer to the numbers in the diagram below. The outer arc is Pluto's orbit (or whatever the destination is). The inner arc is that of the Earth. The red path is that taken by the ferry. The green lines show the angle and furl state of the ferry.<ol type="1"><li>The ferry, having just picked up its load in a orbit well outside the Moon's, unfurls its sail in a way that slows down its radial</li></ol> <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

nexium · Sep 7, 2007

Most everyone, but me, thinks solar sail can manuver like a sail boat on an Earth ocean. The sail boat has a large keel which interacts strongly with the water. Worse I'm not sure a solar sail can manuver without the help of some ion engines, which will not be able to tact toward the sun, unless they are very powerful or you fold up the sail. Neil

willpittenger · Sep 7, 2007

You can't maneuver a solar sail like a keeled boat as there is nothing to push on. My solution was to balance gravity against the solar pressure on the sail. This is why I have the ferry angling the sail around and, at times, furling it. The only thrusters needed would be to spin the vehicle. However, gyros might be better for that as ion exhaust would have to be aimed away from the sail. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

hydra1 · Dec 18, 2007

Why can you see 2500++ light years away but can get a good picture of pluto?

vogon13 · Dec 18, 2007

We both can see the same moon in earth's sky, yet we cannot see each other . . . . <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

alokmohan · Dec 18, 2007

I dont brush aside the question as humour.I somtimes doubt whether all these pics are true.

adrenalynn · Dec 18, 2007

Yeah, I make all my pictures with photoshop. Which is why some of them come out great and others don't. The answer to the OPs question is: Pluto is a tiny object with very little reflectivity. It's average apparent magnitude is around 14.6. By way of example: the apparent magnitude of the star Capella is 0.00. Each magnitude is, as you might guess, an order of magnitude. So Capella is about 146 times brighter. Capella has 2.69 times the mass of our sun, about 10x the radius (IIRC). It's about 42 ly from us. If I toss a pea in the bushes across the street from your house, you'll have a hard (ie. impossible) time seeing it. If I set up a carbon-arc spotlight 15 miles from your house, you'll shade your eyes with your hand and still see the light. That said - I can see and even photograph Pluto with a small and relatively inexpensive telescope. I just can't resolve the detail that I can get from something tremendously bright. It's about light and size. <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

vogon13 · Dec 18, 2007

Is it that hard to tell when I am being profound instead of funny ?? <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

3488 · Dec 18, 2007

Hi Hydra1, Think about this, What's easier to see? Mount Everest from 40 KM away or a molehill from 60 metres away? Or a Football Stadium floodlight from 5 KM away or a hand held LED torch from 100 metres away? Its a question of scale. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

zeldun · Dec 18, 2007

Hi, I think that you can follow this up with another question. Why is it that probes sent out to the outer planets often take so fuzzy pictures? And why are they almost always in black and white or fake colour? So far I have seen no detailed pictures of Titans clouds for example. Can someone please explain the often so bad quality in pictures taken by probes? And also explain why they use fake colour. I don't think it is because NASA couldn't afford good cameras, but it has to be some reason or have I just missed all the true colour detailed pictures?

adrenalynn · Dec 18, 2007

False-color has more scientific value. These photos are not about being "pretty" and having "artistic value". That what us amateur photographers are for. <img src="/images/icons/wink.gif" /> False color images are shot through (or processed through) filters that are designed to reveal detail in things like chemical makeup, depth, viscosity, etc. Black and white reveals more contrast. The fuzzy nature really has several things at the core. First, remember the data is being sent over vast distances with severe power requirements. Transponder time is very "expensive" in power consumption. That power also has to go to things like telemetry and command structure. So the data is highly compressed. The cameras are very high resolution, so the data has to be compressed more to preserve the all those pixels. Weight also has to be kept down to something approaching zero. The data packet transfer is unidirectional. So signal processing "magic" needs to be done for data correction. Predictive algorithms such as various forward correction is used. These cameras are being used in the depths of space. Cosmic radiation as well as more traditional radiation has to be accounted for. This streaks and fuzzes the image. Shielding is very difficult because the lens has to be exposed. Finally, the cameras that have made it to the outter edges of our solar system to explore things like Pluto are coming up on a couple decades old. Technology has progressed massively. In a couple decades we'll get to see results from the technology we have developed today. <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

alokmohan · Dec 18, 2007

3488 has asked tough question.I dont know the answer.

adrenalynn · Dec 18, 2007

The answer to his questions is self-evident. And they're the same questions I pose as explanations in my post. Since they apparently AREN'T self-evident to you: It's easier to see a mountain from 40km than it is to see a molehill from 60m. Go try it yourself. <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

zeldun · Dec 18, 2007

Adrenalynn, thanks, that was very helpful.

alokmohan · Dec 18, 2007

Adrenalyn thaks a lot .Now I pass the test.

adrenalynn · Dec 18, 2007

Sure! Just to quantify one of things I wrote - Pioneer 11 (our close-pass to Pluto) [oops - incorrect - see below] was launched April 6, 1973. That's coming-up on 35 years. Three and a half decades is a _looong_ time in technology! Put that in perspective the computer you're using right now would have taken-up an entire fair-sized building and still wouldn't quite be that fast. The Internet didn't exist. Cell phones didn't exist. CD players didn't exist, let alone DVDs. Even the Walkman didn't exist yet. Analog audio cassette tape was new and exciting. Digital cameras as we know them didn't exist. Given the Photopolarimeter in use on Pioneer - it's *stunning* to me that it gets such amazing pictures. An early 1990s webcam would crush it. Sorry - Voyager 2 appears to have been the closest pass to Pluto. Launched in Sept 1977. Close enough. New Horizons will, of course, get closer in July of 2015. It'll be interesting to see what it delivers since it was launched in 2006. <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

zeldun · Dec 18, 2007

Indeed, its very exciting.

3488 · Dec 18, 2007

Hi Zeldun, Adrenallyn is correct. I too am not sure that pictures from outer solar system probes are fuzzy. Both Voyagers, Galileo, Cassini & New Horizons have all delivered stunningly high quality imagery without fail. Many, no correct that, most of those images are crystal clear & really quite stunning. Look at what Cassini is sending back from the Saturn system. Notable earlier examples: Voyager 1 sent back from Jupiter & Io, Saturn, Mimas & Rhea, Voyager 2 from Jupiter, Ganymede, Callisto, Tethys, Iapetus, Uranus, Miranda, Ariel, Titania, Oberon, Neptune, Triton. Nothing fuzzy or poor quality about these examples. Galileo from the Jupiter system & the recent New Horizons Jovian adventure. Nothing fuzzy or poor quality there either. Please remeber lighting levels are very low, this far from the Sun, so getting high resolution images is not so easy. Also the Voyagers are both on solar system escape velocities, thus compounding it further. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

adrenalynn · Dec 18, 2007

I think people have come to expect Hubble-like images. It needs to be appreciated these Hubble images are cherry-picked images intended to wow the public and further NASA's mission [of funding]. Many hundreds of hours goes into image processing them to make them "look pretty". The science-oriented images look a bit different. <img src="/images/icons/wink.gif" /> That said, I do agree that those images returned from the escape vehicles are amazing. Especially when you figure that some of them are running about 1.4kbit/sec data transfer rate. Yes - about the speed of a 1200 baud modem! <div class="Discussion_UserSignature"> .bipartisan (bī-pär'tĭ-zən, -sən) [Adj.] Maintaining the ability to blame republications when your stimulus plan proves to be a devastating failure.IMPEACH OBAMA! </div>

Mee_n_Mac · Dec 18, 2007

One last observation (!) ... when we see a star 2500 LY away we don't see it's sunspots do we. So the OP's comparison is somewhat of a strawman. <div class="Discussion_UserSignature"> -----------------------------------------------------Ask not what your Forum Software can do do on you,Ask it to, please for the love of all that's Holy, STOP ! </div>

MeteorWayne · Dec 18, 2007

One correction Adrenelynn. Each magnitude step is 2.5 X in brightness, so Capella is 2.5^14.6 brighter, or 645,000 times brighter than Pluto. Wayne <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

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