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A few weeks ago I was at the 2003 MAPLD (Military and Space Applications of Programmable Logic Devices) conference, and one of the talks was by Roger Launius, chief historian for the Smithsonian Air and Space Museum. He talked about the history of NASA, in the context of the Columbia disaster, what he thought lead to the failure, and where NASA could go from here. His outlook was pretty grim, but he made excellent points, which enraged a large portion of those attending the conference, half of whom were NASA employees.

Essentially, he said the Shuttle failed (and he didn't just mean 'crashed', he meant, failed to live up to its hype, to do real scientific work in space, and be cost effective) because it was designed wrong. It was designed to be all things. It was designed to transport people into space. It was designed to transport cargo into space. It was designed to conduct research in space. By trying to do all of these things, it failed to do any of them well. He made a number of other vary salient points about the reasons we should or should not send people into space, and the impact of public opinion and politics.

To keep this OT, I'd have to say, considering the historical perspective I learned from Dr. Launius, I like the capsule approach the best for transporting humans into space. It's cheap, it's effective, and it's less likely to break. I'd like to see NASA design vehicles that are inteded for a specific purpose, and do that purpose well. We have a space station for science that can only be done by humans in space (which there isn't much of...how do you really do microgravity experiments with people on board bumping into stuff, and jarring the place around?), we need a low-cost vehicle for transporting cargo, and a high-safety vehicle for transporting humans.

You've got it backwards. The Farscape module was based on the (now cancelled) crew return vehicle for the ISS. The vehicle was dubbed the X-38 through its testing-- here's a quick link:

X-38 Stuff

measuring the speed of microwaves, not light

Microwaves are light. They just have a longer wavelength. The speed is the same as for visible light. It is only dependent upon the medium.

if it needs 2 minutes to melt some chocolate, that's not very fast.

Otoh, I wholeheartedly agree with this statement.

Deep Space 1 certainly did not fail (who in their right mind would send a multi-million dollar probe up without testing it first?!) Here's proof.

Deep Space 1 ion engine lab videos Pictures of the DS1 project (scroll down for ion engine)

Official DS1 site

They extended the mission MULTIPLE times, and even landed it on an asteroid (yes, landed, very softly too) This European mission isn't even worth mentioning. They're going to map the moon, whop-de-freaking do. The only reason it's getting press is because of the ion engine, which if the press cared about the American space program they would have reported that NASA has already succesfully untilized ion engine technology in space for hundreds of days in a row. It was shut down after hundreds of days of use (and after it had completed its mission). Then they restarted the engine (unprecedented!) by 'shaking it up' with the gas maneuvering jets. You've misread your space history, jd.

Deep Space 1 certainly did not fail (who in their right mind would send a multi-million dollar probe up without testing it first?!) Here's proof.

Deep Space 1 ion engine lab videos Pictures of the DS1 project (scroll down for ion engine)

Official DS1 site

They extended the mission MULTIPLE times, and even landed it on an asteroid (yes, landed, very softly too) This European mission isn't even worth mentioning. They're going to map the moon, whop-de-freaking do. The only reason it's getting press is because of the ion engine, which if the press cared about the American space program they would have reported that NASA has already succesfully untilized ion engine technology in space for hundreds of days in a row. It was shut down after hundreds of days of use (and after it had completed its mission). Then they restarted the engine (unprecedented!) by 'shaking it up' with the gas maneuvering jets. You've misread your space history, jd.

Deep Space 1 certainly did not fail (who in their right mind would send a multi-million dollar probe up without testing it first?!) Here's proof.

Deep Space 1 ion engine lab videos Pictures of the DS1 project (scroll down for ion engine)

Official DS1 site

They extended the mission MULTIPLE times, and even landed it on an asteroid (yes, landed, very softly too) This European mission isn't even worth mentioning. They're going to map the moon, whop-de-freaking do. The only reason it's getting press is because of the ion engine, which if the press cared about the American space program they would have reported that NASA has already succesfully untilized ion engine technology in space for hundreds of days in a row. It was shut down after hundreds of days of use (and after it had completed its mission). Then they restarted the engine (unprecedented!) by 'shaking it up' with the gas maneuvering jets. You've misread your space history, jd.

The Nakhla meteorite you are referring to killed just one dog. Several people have been injured by meteorites. (I remember at least one local newspaper story of a guy who got a fist-sized meteorite through his windshield at 80 km/h, and was injured when he drove off the road.)

A meteor does not necessarily reach ground, it may burn entirely in the atmosphere. In contrast, a meteorite hits the ground.

In 1908 the Tunguska meteor injured several people, one of them died a few days later. Dozens of reindeer got killed, and they were 30 km away. I assume some wild animals closer to the site were also killed, but the site was searched only in 1920s so we have no record on that. The blast was equivalent to 15 Megatonnes, so only one dead human is really good luck.

Don't worry about it too much. A Tunguska-sized event should take place only about every thousand years on average, and would be similar in severity to a major natural disaster in a local area, like a volcanic eruption (although it would most likely be a complete surprise, so evacuation might not be possible). No worldwide consequences.

This isn't the first time an ion engine has been used in space. NASA's Deep Space 1 probe toured the solar system for over 3 years with an ion engine. This probe isn't very well known, since it was just a test bed. But in the end it made some history by performing the closest encounter ever with a comet.

(Frankly, the physics of using rockets in space has never made sense to me - how do they go anywhere? - but it seems to work, so that's fine.)

Rockets use the same priciple that ion propulsion uses, the law of action and reaction (one of Newton's Laws, can't remember which one off the top of my head). Basically matter is accellerated out the back of the engine (by chemical means in the chemical rocket engine, and by using electro-magnetic forces in the ion propulsion engine). This accelleration causes causes a force to be placed on the engine that is equal to, but oppisite in direction, to the force accellerating the matter.

To answer your first question, Deep Space 1 used ion propulsion.

here ;)

Also, some kind of printed emails can be found in pdf format at this page at NASA. They say something to the effect like:

Engineer: Hey should we, err, take a picture with a DOD satellite or something? That debris looked a little nasty on the takeoff.

PHB: Nah, its OK.

This report was released one month ago today, so its kinda old news. I was floored the 1st time I read it. Look around page 150 or so of the whole document.

The parent's link is helpful, but I found these to help after reading the above:

http://techreports.larc.nasa.gov/ltrs/PDF/conf-1 3- ispa-unal+dean.pdf
and
http://www.sbaer.uca.edu/research/2003/swdsi/Pap er s/011.pdf

These show a lot more in examples, and explain more of the math.

Why couldn't we put this lab in orbit?

The main reason is that the effect is so weak. A mission concept called LISA is being studied by ESA and NASA. The idea is to have 6 spacecraft orbiting the Sun, which together form a interferometer several million kilometers in size. The catch: Because the waves are so weak, the distances between these spacecraft would need to be controlled to within about a nanometer (!) to have any hope of detecting a signal. Needless to say a VERY challenging mission.

A lot of other interesting missions would be enabled by good formation flight technology. Look at NASA's Terrestrial Planet Finder mission, or the ESA's similar Darwin mission.

NASA used Ion propusion in their Deep Space 1 craft, and used it to take pictures of an asteroid, back in 1998. Maybe new for Europe, but it's been tried and tested already.

Actually, Ion engines have been used in space since early 90's but primarly as station keeping thrusters for satilites. You are correct that competition is good for NASA, but at this very moment, the Air Force is funding the Ion Space Propulsion Lab where I am currently doing my PhD research.

Ion engines are a mature technology. They have existed since the 60's, and are currently used for stationkeeping on a great number of satellites. They performed far beyond expectations on NASA's Deep Space 1 mission in 1998, and are a logical and economical choice for any mission of relatively low mass where time is not a critical factor--which it is not in this case.

-Carolyn

You probably are talking about the Deep Space 1 mission. NASA also is planning a probe to Jupiter's moons using an ion drive.

Solar electric propulsion is hardly new. It's been used for getting communications satellites out to their final geosynchronous orbits for a number of years now, and NASA demonstrated using solar-powered ion engines for interplanetary primary propulsion on Deep Space 1 back in '98.

What ESA is claiming is new about this mission is that they'll be combining ion propulsion with gravity assist maneuvers. AFAIK that hasn't really been done yet (although I know some guys at JPL who're working on it), and given how difficult it can be to work out low-thrust trajectories in the first place I would imagine that successfully throwing gravity assists into the mix would be a significant acheivement.

It's a lot more economical. It means that they can launch a vehicle on top of a commerical GEO booster, and that the vehicle can make its own way out of geostationary orbit into lunar orbit.

Yes, the Apollo program managed to do the job in four days. But it did it by launching a huge, custom-made multistage vehicle on top of a Saturn 5, which was already a huge, custom-made multistage vehicle. The part of the Apollo spacecraft that actually entered lunar orbit consisted of the lander, the command module, and the service module. The service module was by far the largest component and was mostly fuel tank. It weighed twenty-five tonnes.

SMART I, OTOH, weighs less than half a tonne. Slight difference. It's actually sharing its Ariane 5 booster with a bunch of other satellites.

What I would like to know is what SMART I is going to use for station-keeping around the moon. Luna is lumpy; the part that faces the Earth sticks out, and that makes for really weird gravitation fields around it. There are, basically, no stable orbits around it. If you don't keep adjusting your course you'll either get slung off into space or plough into the ground. Is the ion drive powerful enough to do this usefully, or does it have conventional thrusters as well?

And the payload isn't really greater at all.

The payload in the Apollo program was launched from a Saturn V, which can put nearly 120,000 kg in low orbit and so had enough oomph to put it's payload immediately into a lunar trajectory. The payload for this mission will be launched from an Ariane V, which can only put ~16,000 kg in low orbit, but at (IIRC) a tenth the price.

Hopefully they can perfect the ion drive, however through this to increase the speed and payload capacity.

The drive itself is pretty near perfect; the problem is that if you're going to kick out exhaust at such insane velocity that you don't need a whole lot reaction mass to get good deltaV, then you need a whole lot of energy to get good deltaV instead. And these guys are getting that energy from solar panels, which takes a while. If we had that anti-matter reactor you want (or cold fusion, or anything else providing lots of energy from little mass) we might eventually want something fancy like VASIMR, but in the short run we'd probably just plug the reactor in to bigger or more ion drives.

They've been used as thrusters on satellites for years, and of course NASA's Deep Space 1 was powered by one back in the late 90s.

Ummm...this is nothing new.

How do you get rid of nasty infections? Autoclave! Heat things up enough to smoke out all those nasty hoomins and things can get back to normal around here.

As for volcanos, it looks like the production of CO/CO2 in eruptions can have an effect on global warming. It turns out, however, that the ash/SO2 released into the atmosphere has a cooling effect. It also helps scatter sunlight, allowing for more robust tree growth which leads to more carbon being taken out of the atmosphere.

So, all we need to happen is for the Yellowstone (NetBSD) volcano to erupt (supposed to be violent enough to wipe out hoomanity) and fill the skys with enough ash and SO2 to bring on Fimbulwinter to slow down global warming. Or have a big rock smack into the Indian Ocean.

But most environmentalists beg that question, and accept it as a given that "the weather is getting more extreme". I disagree with that premise and defy someone to show me figures showing drastic increases in precipitation, temperature, storm destruction, etc. over a 30+ year span (to leave out the 20-year sunspot/storm cycle).

Here you go, enjoy. I could find only ONE link that disagreed that weather was getting more extreme, from NASA:

Even with Needed Corrections, Data Still Don't Show the Expected Signature of Global Warming.

The rest say a definite YES that the weather is getting more extreme, most that it is caused by global warming, and some that this global warming is caused by humans:


NOVA and FRONTLINE join forces to investigate the science and politics of one of the most controversial issues of the 21st century: the truth about global warming.

I would especially like to draw your attention to

this graph.

2001 report by the Intergovernmental Panel on Climate Change


TESTIMONY OF THOMAS R. KARL, DIRECTOR NATIONAL CLIMATIC DATA CENTER NATIONAL ENVIRONMENTAL SATELLITE DATA AND INFORMATION SERVICES NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION BEFORE THE
COMMITTEE ON GOVERNMENTAL AFFAIRS UNITED STATES SENATE.


WMO STATEMENT ON THE STATUS OF THE GLOBAL CLIMATE IN 2001


National Oceanic and Atmospheric Administration - Global Warming - Frequently Asked Questions

Cheers,
Lars

http://earthobservatory.nasa.gov/Library/CarbonCyc le/

Or maybe there is more carbon dioxide because there is not enough dust in the air, so Ocean Plant Life Slows Down and Absorbs Less Carbon .

Depletion of the ozone layer is a separate issue to global warming. Tropospheric ozone, on the other hand, is related to global warming, in that it is one of the list of greenhouse gases.

No need to panic, there is no global warming greenhouse effect, as these new satellite pictures of earth show..

Well, a "fission-reactor ion-drive" is really not that outlandish at all -- though there isn't much reason for the fission reactor when there is plenty of light energy floating around in our solar system to power the ion drive. Deep Space 1 uses an ion drive...more info here

And I don't know why you want a quantum computer on your mission to mars....doesn't seem like you'll really need to be factoring large numbers out there. Plus, I can watch videos from space on my Linux desktop.

Then that is where I lose you...true AI? A power company who doesn't charge you through the nose? These things that will never happen...

on the Cosmic scale, the universe is always throwing sparks at things

Like this one. Flat bottom, paired damage, steep sides, right-angled crossings, almost ignores surrounding terrain... doesn't fit anything except arc machining. A good one to watch from a long way off. Notice also the paired craters scattered all about.

Cassini sent the movie of Jupiter's pole as it flew by on its way to Saturn. Given the enormous winds on Jupiter, the eye could extend a dive into the atmosphere a lot further than going in anywhere else as the pressure has got to be substantially lower inside the eye. Getting a signal out of there would be tricky but just try and imagine what's at the bottom of the eye.

nope, two streams are in windows media format. Though I'm not sure if that's better or worse.

The quest to get usable data out of Galileo has driven some of the world's most advanced communication and signal processing algorithms over the past few years. AS a result they were able to achieve a better than ten fold increase in data rate from 10 bps to a maximum of 120 bps, a pretty spectacular achievement that saved the mission. You can read the technical details here

Since Jamie rather thoughtlessly posted a direct link to the JPL real stream and now none of us can see it; please visit NASA's website listing all the alternate feeds for NASA TV and use one of these instead.

Don't forget Pioneer 10!
Pioneer 11 is also somewhere though scientist do not know if 11 is still transmitting signal. After 4 million years(!) it will reach constellation of Aquila.

FYI, NASA TV has a live webcast here. UATV is another place to watch as they are rebroadcasting the NASA channel...

Use internet to watch Galileo spacecraft crashing into Jupiter
Galileo has less than two hours before crash and slashdot still hasn't report this ?

Sunspots are not "holes into the Sun". Sunspots are cooler than their surrounds because magnetic fields in the region slow the convection which brings hotter matter up from the interior.

They are indeed holes into the Sun, but "only" a few thousand km deep. The patch of Sun underneath the sunspot and the layer of turbulence below it is hotter than the surrounds... but it still begs the question about the Sun in general being cooler under the surface than on top.

Also, the current LASCO movie of the solar corona doesn't show any solar "storms" coming our way in the last few days (they show up as expanding halos all the way around the Sun), although there were several that went off to the side in that period.

For all of you who keep asking, "What is telstar?" - here's the results of a Google:

http://roland.lerc.nasa.gov/~dglover/sat/telstar.h tml

Use this and get truly large distances.

Nobody made any mistakes, because nobody knows what really happened. Elsewhere there are examples of gas giants orbiting within 3-7 million miles of their stars' surfaces. Perhaps the enormous mass loss rate is bleeding the gas giant of its orbital angular momentum and essentially driving it into the star that is frying it. Or if the star is rotating slower than the planet is revolving around it (the previously mentioned evaporating gas giants have a period of 3-4 days, about a tenth of the rotational period of our own sun), then the induced tidal bulges will cause the planet to transfer its orbital angular momentum to the star's rotational angular momentum (and this could increase convection, allowing the star's energy to escape faster as light). Notice that in this case the planet is transferring energy to the star without even touching it while simultaneously falling towards it (the reverse process is happening here on Earth, where the rapidly rotating Earth is using its tidal bulges to slowly increase the orbital radius of the Moon, and we've actually been able to measure that increase). So there are a variety of ways a star could eat a planet. You seem to favor the expanding red giant model, so I'll quote from this article:

"In principle, that explanation seems OK," says John Lattanzio, director of the Centre for Stellar and Planetary Astrophysics at Monash University. But he says the star was too hot to have been a red giant. "It was probably one that was on its way there - that could fit the parameters."

And also the equation in my previous post is surprisingly robust. It should work quite well once the planet dips into the outer layers of star, no matter whether the star grew to meet it or it fell in. Also, one factor that I ignored but that works in my favor is the mass lot rate of m. The energy per unit radius lost by the planet decreases linearly with a decrease in m. Therefore the planet will be losing most of its energy when it still has most of its mass and before it gets far enough into the star that the force of gravity actually weakens (note that I've been treating M as the mass of the star interior to the radius of the planet's orbit, outside M is merely the mass of the star, but inside it decreases to 0). Once the star ate the first planet, it did increase in size, so your idea of how it eats is valid for the second and third planets.

Check out:

here, here and here

This one is my favorite.

"Your comment has too few characters per line (currently 6.1)" blah blah blah...

S

Check out:

here, here and here

This one is my favorite.

"Your comment has too few characters per line (currently 6.1)" blah blah blah...

S

Check out:

here, here and here

This one is my favorite.

"Your comment has too few characters per line (currently 6.1)" blah blah blah...

S

Check out:

here, here and here

This one is my favorite.

"Your comment has too few characters per line (currently 6.1)" blah blah blah...

S

What needs to be overhauled is how the astronomers interact with the press. Perhaps they should simply not hold press conferences on "maybes". Especially when certainty will be available within a few days anyway.

Guess what: they don't. They just keep a list of impact risks and every year or so some bored journalist finds the page, takes the top one off the list and writes a story about it.

Probably. But would we be better off then? Let's face it, the chance that we're going to be hit by an asteroid is there. I remember the Shoemaker-Levy 9 crash on Jupiter and the craters on every other planet in our solar system prove that every now and then something big comes down.

So while it would be easier to shut our eyes for it, it would probably be best if we all got scared. A lot. That way we'd make the best effort to foresee these things and take counter measures. Let's face it: we've got plenty of ways to eradicate our neighbours (Vietnam, Afghanistan, Iraq, North-Korea to be next?), but somehow we don't seem to care about this particular enemy...?

For that matter, a little brown pebble could whizz past this little blue one, and nobody would really notice as billions died instantenously.