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Also, the solar sail is not designed to work with "solar wind." See FAQ

And where would this be, exactly? Where there's no gravity?

All a solar sail does is to change orbits, by speeding up or slowing down. But changing the orbit of an object in earth orbit to a Mars orbit might conceivably be a very useful thing to do. Next time, before theorizing, read the FAQ.

What, like this one?

Read the artical first next time mate.

-Alex

planetary.org

Discovery.com

Some of the context is redundant, the first link is the most informative.

Now, I was following astronomy and space since 1989, when Voyager 2 reached Neptune, on National Geographic and other sci mags, so I already had a fair idea about the concepts being taught in class. Like you, I somehow had this innate urge to be an eager beaver, and, actually stood up in the class and pointed out that the textbook's data was 30 years old, and that Jupiter had, in fact, sixteen moons. (Nat Geo, August 1990; ol' Jupe seems to have amassed more moons recently).

Been 11 years now, the same lady taught my younger siblings and has developed a friendship with my mom that's continued even after I graduated from school, but I don't think I can ever forgive her for snubbing me for "confusing" the class with "new ideas".

The Planetary Society as mentioned in the article has their own solar sail which is going to be launched in a few months.

They are the ones actually doing something about this, NASA and the ESA have yet to get off their butts and actually do any real tests.

You can join them and give support to these and other space projects. Much better than complaining about NASA.

They also have a good overview of solar sailing on the project page here.

They also have a good overview of solar sailing on the project page here.

There is a very introductory book about solar sailing by Louis Friedman, Executive Directory of the Planetary Society: it's Starsailing: Solar Sails and Interstellar Travel (yeah, yeah, it's amazon, thbbbppp) and here are some selected chapters. It rocks because it walks you through the equations and such. It's really NOT hard to understand. I found it in my high school when I was a kid and really fell in love with the whole concept. It really rocks.

In the book it points out that the concept was tested with the Mercury probe that NASA sent way back (Mariner-10) in that they used the solar panels to get a spin from light pressure (iirc, it's in the book and I haven't read it in 10 years...)

Oh, man, I read your post and thought "Robert Forward is dead? I hope he's mistaken about that." Unfortunately, he died last year, and I for one will miss him for his unique style of hard science-fiction and his innovations in physics and space travel. He did a lot of work on tether propulsion systems. Unlike Arthur Clarke, he patented a lot of his inventions. I wonder if the company he set up will see any money from their use, or if he was just a little too far ahead of his time?

There's plenty of that already. IIRC all of the landers have had such cameras. This is one link and this is another to such images but there are plenty more (Google is your friend...). What I'd really like to see is, however, more than still images - ie. some movement by the rovers and so on. However, I assume that the scientific value of that wouldn't be much higher than that of high resolution still images and thus doesn't justify the amount of data that needs to be transferred.

Well, just make sure its on this list (Petition to Call for the Support of Future Space Exploration.) The Planetary Society does more than just SETI, you know.

Well, just make sure its on this list (Petition to Call for the Support of Future Space Exploration.) The Planetary Society does more than just SETI, you know.

For example, when my computer was working on the data in an area near the equator at the body of leo (look at the third yellow square for leo--that's approximately the location), I mixed in some Elvis with the data, and got back a 20-second pause in the bitrate.

I have to say: it's really been great to be able to analyze the dynamics of distributed processing, and I'm really grateful to the SETI-at-home project for letting me be a part of it.

[PS... on a different note, it's interesting that the greatest frequency of data is right along the milky-way's equator. On a not of caution, I think that says something more about the system they're using, than about their data.]

In fact the re-observations happened a long time ago (in March i believe) but the scientists are preparing the data to analysed by the SETI@Home program. Apparently it is quite a hard task as they used different instruments than for their usual data.

Last SETI Update : 21/05/2003

this article?

Although the SETI@home team was ready to pounce on any possible extraterrestrial signal the minute it was detected, nothing resembling such a signal was detected in real time, during the observations. This, however, is no cause for discouragement: real-time analysis is very rough, and would only detect the strongest and most obvious extraterrestrial signals.

Check it out...
1 - 20 of the computers who crunched data that lead to discovery of these "reobservation points" come from computers in Antarctica!

space may be full of resources, but unlike the resources in India, we have NO way to get TO them, extract them, and send them back, in any sort of reasonable way.

Thats a limited view on what counts as a resource. Without the money that went into space exploration, we would not have satelites. We wouldnt have GPS, we would have trans-global phone calls, we wouldnt be able to talk to people in Antarctica (the guys that discovered the hole in the ozzone layer - that was pretty essential research given the cost), we wouldnt have satelite TV, we wouldnt have live news reports from the other side of the world, etc.

we've flushed TRILLIONS of dollars into space exploration

Wheres that money gone? Its paid peoples wages, its bought goods. It's stayed in the U.S. economy.

Whats it got out of it? Scratch resistant lenses, blood presure measurers, pacemakers. I suggest, as the other guy said, you should read up on the medical benefits. The environmental/social benefits include things like the EPA, Greenpeace and Earth Day. Of course, theres Scores more benefits.

' Same thing goes for this moronic 'search for life'. I'm sure there IS life elsewhere in the galaxy. Will we ever find out or be able to do anything about it? Nope. Too far away. Who gives a crap

Lots of people actually, however SETI isnt government funded so thats not a valid argument.

What the HELL did going to the moon get us? ABSA-fucking-loutley NOTHING except a bunch of damn rocks sitting in a display case.

A picture of Earthrise. A realisation of how fragile our planet was. Also bragging rights over the USSR, which was important after they launched sputnik and Yuri first.

we've got damn good collaborative evidence that the speed of light is the end of the speedometer

So, sorry, I didnt realise that was you Mr. Hawking. The BPP is/was working on ways. Obviously its a long way off, but the potential might be there.

we're already doing that juuuuust fine in Iraq

Iraq, space exploration. I see the connection *rolls eyes*

That said- if mainstream media would do a better job of citing sources, critically evaluating credibility (even when less credible sources say more entertaining things), and giving reasons and deductions instead of rote facts, people might learn that science is a process, not a dogma.

The same problem exists for science ed- if you don't tell students how we got from Darwin's observations and theories to empirical tests, the compelling stories of trusted parents and friends will outweigh the rare knowledgeable biology teacher. For every fact, people should have an idea of the process of thinking behind it. (And maybe the world could use more stories of heros who succeed with knowledge, rather than manipulation and smokescreens.)

When the system is found succesful NASA plans to use it in future probes, like the Interstellar Probe. That thing would travel 200 AU (Astronomical Units) in 15 year. Much faster than the Voyager and Pioneer crafts.

Another, more controversial, propulsion system is Nuclear propulsion. Technical information can be found here

This mission should be shut down through peaceful protests before we all end up glowing green.

This concern is understandable, but uninformed. Refer to this page for a technical explanation of the problem and its solution. There is also a wealth of information here.

I, personally, am more concerned about nuclear-powered Cold War-era spy satellites still orbiting Earth than I am about a 21th-century-technology vehicle to be launched far, far away.

Pioneer 10's mission continues. Let's not forget the plaque that Pioneer 10 carries. It was world famous when the probe was launched, because it was mankind's first attempt to communicate beyond the solar system. Carl Sagan designed the plaque to be universally (in the truest sense) comprehensible, at least to any civilization sufficiently advanced to capture it. Next to the map of the probe's origin relative to our galaxy, with its key in binary notation, was an etching of a generic man and woman, superimposed on an outline of Pioneer to give a sense of scale. The man's arm was raised in a gesture that Sagan hoped would suggest friendship. Especially given the public's then-new awareness of threats to humanity's survival as a species, there was something very poignant about this cosmic message in a bottle that had no chance of being seen by anyone for millions of years.

I remember a newspaper cartoon from the day. A man in a business suit and a woman in a dress were looking at the plaque on Pioneer, which was half buried in the ground. The man said to the woman, "They seem very similar to us, except that they don't wear clothes."

detect an asteroid the size of Texas headed straight at us?

Just for the record, Texas is 266,807 sq miles . Does it make sense to compare a two dimensional item like a state to a three dimensional object like an asteroid? How? Compare the surface area of the asteroid to Texas? 4 pi r^2 is the formula for the area of a sphere.

Maybe one should use the largest cross section? This site says Vesta , the third largest asteroid, is the size of the state of Arizona. This site and this site list some of the larger asteroids.

Let me suggest that the chance of Ceres sneaking up on us is not one in a billion, or one in a trillion. Let me suggest it is zero.

Are there any asteroids the size of US states that haven't been discovered yet? None with Earth crossing orbits.

Are Kuiper Belt Objects asteroids? If so Ceres is no longer the largest asteroid. . But it is even more unlikely that something would divert a Ceres size KBO from past the orbit of Pluto to Earth orbit.

How long would it take to divert an asteroid from an Earth impact? Decades? Centuries? Millenia? Anyhow, Deep Impact had the incoming object be a comet. Even with a project to find deadly NEOs, we could still be snuck up on by a long period or extra-solar comet.

Actually there are about 100 people worldwide searching for NEOs according to NASA's Ames Research Centre Asteroid Coment Impact Hazards Website.

The most productive NEO search program is the USAF/MIT run LINEAR which has discovered more NEOs than all other search programs combined.

Other search progrms include

• NEAT
• Spacewatch
• Lowell Observatory Near-Earth Object Search (LONEOS)
• Catalina Sky Survey
• Japanese Spaceguard Association (JSGA)
• Asiago DLR Asteroid Survey (ADAS)

I haven't been able to read the article because it's slashdotted, but it makes me wonder why they would have something like the Torino Impact Scale if they weren't going to use it to inform the public. So far only one object has ever has ever been classifed a "1" on the tornio scale, but that doesn't look like it's going to a a problem. But with most NEOs still unidentified the most likely warning we will have is none at all.

There are a lot of scientific reasons to go back to the Moon - first a lot of questions about the Moon itself, and the early history of the solar system that can be learned from lunar cratering. Of most interest in this is the South Pole - Aitken basin, which is mostly on the far side; the south polar regions of this very deep basin have craters that may hold water ice and other cometary debris. But the basin material is itself of some geological interest, and a sample-return mission to this area was listed as one of the highest priorities in planetary science in the recent NRC decadal survey.

Second, for science, is the potential of the Moon as a platform for observation of the rest of the universe. A lunar telescope has the same lack-of-atmosphere advantages of Hubble, but could be constructed much larger than is possible for a free-space telescope (with current technology) with use of in-situ materials. This is particularly important for infrared and ultraviolet/x-ray astronomy, for which much of the spectrum is almost completely attenuated in the Earth's atmosphere and space is the only real option. It makes a lot of sense to base the next generation of space telescopes on the Moon, though I have not seen much movement in this direction, other than some early-stage proposals.

Space solar power is considered by many to be the only long-term solution to Earth's energy needs that meets both global energy and environmental requirements over the next 50 years. Making use of lunar materials, possibly even generating the power on the Moon, is the only realistic option for building these things on the scale needed. If this globe could ever manage to get its act together and move beyond carbon-based fuels to invest in the future, the Moon has a major role to play.

Finally, space tourism has been in the news, and private companies are starting to look at orbiting hotels and lunar excursions - for those who can pay of course. With the right price, demand can be expected to be huge :-) Retirement to the Moon's low gravity might become a major draw as well.

So the Moon has a bright future - if we could just pay it a bit of attention with all the other distractions the world has to offer these days!

The situation isn't as dire as it sounds. Our dominant problem has been that the falling economy has caused some of our sponsors to withdraw support. With support withdrawn, we are denied matching funds from the University. Essentially, the University is witholding funding until we find further sponsors. We are actively seeking corporate sponsors who would be willing to donate, and have their contributions matched by the University. Under the matching program the sponsors must be for-profit industry. If anyone reading this works for such a corporation, please contact SETI@home through our web site.

Individuals wishing to make a contribution can do so through the SETI@home web site. Please be aware that our current largest sponsor is the Planetary Society. A membership to the Planetary Society (assuming it is done through the links on the SETI@home page) may return more to SETI@home than does a direct contribution, as it indicates the importance of SETI@home to members of the Society.

Regardless of the funding issues, we are working hard to make SETI@home II a reality. We have funding from the NSF to develop the BOINC client/server code which will be used as the framework for SETI@home II. We are in the process of building the SETI@home II data recorder. What we do with it (multibeam, wide bandwidth) and where (Arecibo or Parkes) depends upon what we can afford.

We are also seeking NSF funding for AstroPulse and SETHI and SERENDIP V.

That said, things are currently somewhat tight here. We'll need to make do with fewer employees until we're back in the black. I don't think this spells the end of SETI@home by any means.

• More, higher resolution pictures
• Detailed timeline
• A 2 minute NPR segment
• A longer segment at the end of Science News Roundup on NPR

• Reuters
• BBC
• Washington Post

however, some of the press coverage has been sensationalistic. Some either decry that the object was found after closest approach (rather than before) or express concern about the "blind spot" otherwise commonly known to astronomers as the daytime sky.

The NASA page he cites says the plan is to map all the major near Earth asteroids by 2008. How is this pitiful? If extinction class rocks hit us every 10^7 or 10^8 years, how much time can we budget to defend ourselves against the next one? What if it took 10^2 years? Would that be an unreasonable amount of time to be confident we had detected most of them?

The rock last week was about 100 meters in diameter. Tunguska is estimated to have been 60 meters in diameter. Since the mass goes up as the cube of the diameter this one would have been about five times as powerful as Tunguska. The planetary.org article I linked to says one that size strikes us every couple of millenia. Is this program a failure if we can't detect and divert the next Tunguska sized rock? The article says the Tunguska strike was as powerful as the blast from a 16 megaton H-bomb. It said it devastated 2000 square kilometres. That would be a square about 42 kilometers on a side. Ie. Bigger than Monaco, smaller than NYC.

16 megatons? Rick Green's glossary of cold-war terms defined a "small-theatre nuclear exchange" as "Curtains for the actors after just one act, hence the prefix 'small theatre'". Sure, this could be devastating for lots of people, if it too didn't land somewhere relatively deserted, like northern Siberia. But civilization would survive, even if it landed on Hollywood.

The planetary.org article said 25% or more of the rocks that have hit Earth may have been long period comets. Figuring out how to detect and deflect long period comets that might hit the Earth would be much more difficult. Maybe so much more difficult we shouldn't waste any resources trying?

Here is a link offering more info on NY40, and some more info here. And there is a video here.

• SMART-1 from ESA (the only one this BBC article mentions)
• LUNAR-A from ISAS/NASDA (Japan).
• SELENE also from ISAS.
• TrailBlazer and Electra from TransOrbital Inc.
• Lunar Retriever from AppliedSpace Resources
• IceBreaker from Lunacorp
• Lunar Service from Celestis (you have to be dead...)
• Lunar Architecture is a subject of study for HJ Rombaut, including a recent Lunar Base design workshop
• Bill Mook's lunar tours
• The Artemis Project

#2 on the new planetary exploration priority list from the National Research Council is a sample return mission from the South Pole basin of the Moon. So if NASA doesn't have plans right now, they're going to be thinking about it real hard real soon.

Information from the Planetary Society is here Also, the full text (not PDF) is here Also Florida Today has something here There's more, also. Just check Google.

Sigh...the spacecraft is NOT repeat NOT Russian. It is a creation of the Planetary Society, a non-profit NGO founded by Carl Sagan. The Russians are merely providing an inexpensive launch vehicle, no more.

Actually the name of the mission is "Cosmos 1", the solar sail craft itself isn't named yet.

http://www.planetary.org/solarsail/index2.html

Imagine that....people on Slashdot not getting the facts straight...

Well, it's not so much "them." The Plenetary Society is the driving force behind the project, and they're a U.S.-based non-profit. The cool thing about this project is that it's non-governmental. The Russians are launching it bacuase they're the ones with the cheap launch vehicles.

WHY: To conduct the first solar sail flight and demonstrate the technique for traveling between planets -- and someday, to the stars.

Here (from this site).

Here (from this site).

There is more info on the Spacecraft here on the Planetary Society Website.

Here is the co-organisers (Planetary Society) website (deeplinked to avoid crappy flash front page). It's done in conjunction with Cosmos Studios.

There is much more in-depth information and some pictures on both of those sites.

No migration happens because photons have 0 rest mass, and therefore don't have intertia.

Ahh, yes... a very common mistake by the non-physicist. It seems to make sense that something that has zero rest mass cannot possibly have inertia. This is, however, completely wrong. The problem is that massless particals travel at the speed of light, which is where some interesting things happen in the equations. We start out with the general equation:
E^2 = m^2*c^4+p^2*c^2

Substituting 0 for m, we can solve for p = E/c. It's well known that photons carry energy, and thus they must carry momentum. (There are other methods of deriving this, however I will not get into them... pretty much all waves carry momentum, one way or another).

How else would projects like the Astronomical Society's Solar Sail function?

As for this being the primary reason that optronics are better than electronics, I'm not entirely sure... definately massless particals are in general better for things like this (where you want maximum information carried for a minimum amount of energy, in a minimum amount of time). Photons typically propagate faster than electronic signals, and optical circuits usually have a much higher bandwitdth due to frequency-level multiplexing.

Also, it is possible to use physical properties of photons to compute fast fourier transforms, which are especially important for digital signal processing. Not to mention the amazingly fast access times of ultra-huge holographic databases.

Dislaimer: I'm not a physicist, but I'm studying to become one.

-Justin

We'd better hurry up and find those 4 additional Earths, so there can be enough natural resources for everyone to be able to get online!

Solarsail home

The Planetary Society is dedicated to promoting robotic exploration off the planet and is mildly biased against such projects as the ISS and human exploration of Mars and the Moon.

Wrong.

Check out this page.

Since its inception, the Planetary Society has advocated the exploration of Mars?with the ultimate goal of sending humans to the Red Planet


The Planetary Society promotes all types of space exploration to other planets, especially Mars.

Note that the survey was coordinated by the Planetary Society, not directly by NASA, and the Planetary Society has it's own (Carl Sagan memorial) agenda. The survey was at least a lot better than the typical "let me know whether you support or oppose the XXX program I have sponsored that brings world peace, tax cuts for all, and saves the global environment.." survey letters I get from my Congressman. But it could have been a lot better. A box to enter general comments would have been much appreciated, at the least.

4 How do you want to find out about space mission results?
Please indicate in what ways you currently receive news and information about U.S. space exploration activities. - https://planetary.org/survey/

The question and instructions are not the same. I would like to find out about space exploration from lectures by scientists, but don't. I currently receive my space news from astronomy mailing lists.

I chose to answer how I'd like to get that info, as that was what the question in big bold header text was, and what I understand the survey is about.

PS: I have no problem rating the most important thing a 1, and least important 10.

Make no mistake, it does read like a PR stunt, but its not NASA trying to spin to us. This "survey" is in large part an effort by The Planetary Society to justify their goals and priorities, in the near future to NASA and a highly volatile U.S. congress.

Notice, no manned missions? Do you think ordinary people care about them? In large part, having live people on the scene is something that most ordinary folk can relate to more than having robots crawling around or some deep space probe whizzing by. Its also, tremendously greater expense, and there's some debate within the scientific community over the relative value of manned vs unmanned flight, however, the Planetary Society has pretty much always come out dead-set against manned exploration- its just not their priority or interest.I find it curious that while many individual members/supporters of PS (like their founder, Sagan himself) acknowledge an interest in discovering habitats and environments suitable for future human settlement, they've been very loath to begin acting on that today. I suspect that results of the survey are likely to aid PS in representing their agendas to NASA as "what the people really want".

So... NASA wins, PS wins, Zubrin loses, everyone else goes home happy.

Note, I personally appreciate the agendas that both the rabid "humans in space!" and "robots in space!" camps further. Its important to keep them both in perspective, since they each have value.

"We're talking about an impact on Europa, not on Earth. Europa doesn't have an atmosphere (at least, not one that is even comparable to Earth's.)"

The discussion is about impacting Galileo on Jupiter.

I used Earth as a model - a small model compared to Jupiter! If Earth's atmosphere can handle the breaking up of the craft to undetectable levels of radiation, I think the reaction of the craft compacting (and impacting (into, what? Gas for it's first 300 miles or so...)) into Jupiter would have an even less noticable effect. P-238 is not weapons grade plutonium. It's half-life is 87.8 years.

"Plutonium-238 is a non-fissile, alpha-emitting isotope with a half-life of 87.8 years. Given Pu-238 characteristics, it makes it the most capable heat-generating isotope. While selecting the radioisotope fuel, it was important to note certain characteristics: If the radioisotope has too short a half-life, it won't be useful for missions like Cassini, which is scheduled to last 11 years. On the other hand if the half-life is to long, the heat generated from a given amount of radioisotope will be too low, making the RTG heavier and larger. In order to protect people and electronic components within the spacecraft, it's important to avoid radioisotopes that emit gamma rays. It was found that Pu-238 met these requirements.">> Halflife of P-238

Raising ships with ping-pong balls

Solar sails for spacecraft

Laser-powered spacecraft

Supersonic speeds underwater

Fake breastesses

Sometimes it feels so good to be a human being :)

"Has sensational journalism gone too far? Find out at eleven!" - John Stewart

little info about planetary society :)

"The Planetary Society was founded in 1980 by Carl Sagan, Bruce Murray, and Louis Friedman to encourage the exploration of our solar system and the search for extraterrestrial life.

The Society is a nonprofit, nongovernmental organization, funded by dues and donations from individuals around the world. With more than 100,000 members from over 140 countries, we are the largest space interest group on Earth. Membership is open to all people interested in our mission."

so go to their site and apply for a membership. it costs only 40$ (30$ for students) for us in europe. its even cheaper for north americans. most of the money goes to various space related projects. as a member you will also recieve their magazine planetary report which is really educational and entertaining to read.