Have you read 'Project Orion: The Atomic Spaceship 1957-1965' by George Dyson? (ISBN 0140277323 Penguin Press Science) It's a complete history of Project Orion and why it ultimately failed.
There is also an excellent BBC4 documentary called 'By Atom Bomb to the Stars' which has an enormous amount of colour footage of the Orion tests - well worth watching out for.
OK, so exactly how is this supposed to aid space flight efforts?
There is no mention made of that in the article at all.
Would this be completely unconnected with the Hypersonic Cruise Vehicle (Falcon) concept? DARPA's idea for a global hypersonic bomber that could pre-emptively bomb a country back to stone age before Letterman.
Still, the Germans beat DARPA to this idea by about 60 years - meet the Sanger Amerika bomber... an aircraft that would fly right around the planet skipping off the atmosphere like a stone thrown across a pond.
50% wider and roughly twice the mass of the one detected
If both bodies were the same shape the larger would have eight times the volume.
As for mass, Barringer was definitely iron which makes it comparitively rare - less than 6% of observed meteorite falls are iron, yet they make up over 80% of collected meteorites. The latter number is easy to explain - iron meteorites don't look anything like rocks found on Earth, the much more common stony meteorites (which form over 80% of all observed falls) are very hard to distinguish from the stuff on the ground.
More than likely this is a stony body which would give it a much lower density - round about 3.6 gcm-3 as opposed to 7.9 gcm-3 in iron meteorites.
Having said that - a lump of stone that size hitting the Earth would still be comparable to a hydrogen bomb going off - as you say it would have spoiled a whole lot of people's days.
you are an idiot, right? pressurce differences inside a solid mass?
No he's not.
It depends if it solid rock. many stony asteroids are apparently spongy having once contained volatiles that have subsequently been lost to space. These fragile objects will disintegrate in the atmosphere as atmospheric deceleration crushes them.
Its for this reason that carbonaceous chondrite meteorites - the black ones with the exciting organic compounds are relatively rarer on Earth than their abundance in space would suggest. We're regularly encountering them, they just don't make it through to the surface.
Having said that a 25m chunk of anything disintigrating in the atmosphere would produce a blast in the high kiloton, low megaton range. One of these smashing into a city would be a catastrophe.
And they seem to be more common than we think - there is obviously Tunguska in 1908, but then there are reports of something exploding over the Amazon basin in the 1930s, the more than 100 small impacts that hit Sikhote-Alin in Russia in 1947 and the most recently uncovered biggish impact at Wabar in Saudi Arabia - a Hiroshima-sized explosion in either 1863 or 1891 (there is no agreement on the date, since Arabic scholars saw two bright meteors heading in that direction on different dates, it's only recently that scientists have been able to determine the relative youth of the Wabar craters).
Best wishes,
Mike.
Re:Europa is already highly radioactive!
on
Melting Europa
·
· Score: 1
Correct me if I'm wrong, but don't most probes land on the surface?
At the risk of committing blasphemy on/. - if you read the article, this is about a probe that will search for life in the ocean deep under the Europan crust.
Best wishes,
Mike.
Re:Europa is already highly radioactive!
on
Melting Europa
·
· Score: 1
Europa is already highly radioactive. It's around 19 Mrads thanks to this thing we call Jupiter.
The surface of Europa is heavily irradiated, but not the underlying ocean. As far as I know no one is suggesting that there is life on the Europan surface.
Best wishes,
Mike.
Re:It's Open Mic Night at the Astrophysics Lounge!
on
Melting Europa
·
· Score: 4, Interesting
I'd like to see the leaky probe that could rival Jupiter itself in bombarding Europa with radiation.
Except any life on Europa will have evolved away from that radiation since its protected by almost 20km of ice.
The real threat of any contamination from a probe is not so much from radiation as from heavy metals leaching into the environment, but then if the floor of the Europan ocean is anything like the black smokers of Earth's oceans any life should be used to heavy metals.
Best wishes,
Mike.
Re:I've Not Understood The Amiga Strategy For Year
on
Amiga Sells AmigaOS
·
· Score: 1
Cool - thanks for the suggestions!
Best wishes,
Mike.
Re:I've Not Understood The Amiga Strategy For Year
on
Amiga Sells AmigaOS
·
· Score: 1
What really killed the Amiga was the price. By 1992, when the new AGA Amigas finally came out, PC clones with hard drives and VGA cards and everything were getting pretty damn cheap
Not forgetting that if you bought one of the higher end Amigas - 1500/2000/2500/3000/4000 you had the pay for a monitor on top. PC owners got a monitor thrown in with the sticker price which was frequently lower than the Amiga. By the time the 4000 came along - shoehorned into a PC box it looked ridiculously overpriced to all but those people who desperately needed an Amiga.
My 4000 still works, but none of my monitors will synch to its frequency. Sigh - the march of progress.
Apollo is a name given to a class of asteroids - besides since he was associated with the Sun, sticking him out in the darkness wouldn't be fair - and Apollo was not a god you wanted to piss off.:)
Apollo is his Greek name, to the Romans he was Phoebus which I think is still free.
Juno, Diana, Cupido, Minerva, Ceres, Bacchus, Vesta and Flora are all asteroids.
Janus is a Moon of Saturn.
Vulcan was reserved for an intra-Mercurian planet postulated in the 19th Century to explain eccentricities in the orbit of Mercury. It does not however exist.
Given that Europa is a ice world, and it might contain life under it's icy floor, we might find life there in a 100 years.
Europa is only kept molten by the tidal forces induced in its orbit around of Jupiter. Its internal heat sources from radioactive decay are far too small to keep the interior hot.
So unless we can find one of these bodies in a tidal relationship there is no prospect of finding life.
If this holds true in the Oort cloud, in particular, there could be some pretty big objects. Even a Jupiter sized object might be able to hide from the Infrared surveys (the best way of detecting such an object).
Clyde Tombaugh who discovered Pluto performed an exhaustive search for Planet X for several decades. From his results he concluded that there were no undiscovered Jupiter-sized bodies within 470AU of the Sun, and no Neptune-sized objects with 210AU. (Pluto is never more than 50AU from the Sun).
The Oort Cloud is believed to have been populated by planetismals thrown out of the early inner part of the Solar System by the formation of Uranus and Neptune. They would have slungshot smaller bodies into the outer darkness into orbits that match the hypothetical orbits in the Oort Cloud. They would not have been able to shunt anything larger out that far - at least not without disrupting their own formation.
A further problem is that planet formation models run into trouble this far out. Distances between the planetismals that made up the proto-planets would have been so great, and relative velocities so small that its hard to see how they would ever have collided to built up a bigger planet.
Is it a possibility that Beagle-2 croaked during the Solar Flare event which happened during the journey? Serious question not answered earlier.
Mars Express reported all systems okay in the late November 2003 pre-release check, but I couldn't tell you how many of Beagle 2's systems were given a check-up at that point.
How about the Open University opening the software so that many eyes can see if we can find any bugs?
The descent software was written by Astrium. I'm sure they are just as keen as any defence contractor to let people see their source code.:)
If you'll remember, NASA adjusted the Rover's landing parameters immediately before landing, forcing the parachute to deploy sooner to compensate for lower atmospheric density. That very well may have saved the mission, because the chute still deployed at a lower altitude than expected.
IIRC they tweaked the programming on the second lander following Spirit's descent to the surface and analysing its data. This was the first indication that the pressure was lower than expected.
Either Beagle 2's landing sequence was such that it could not be tweaked en route, or ESA overlooked the opportunity to make such an adjustment.
Beagle 2 could receive software upgrades in-flight, but by the time NASA measured the pressure in the atmosphere, Beagle 2 was long-lost.
Best wishes,
Mike.
Re:Has the atmosphere DRASTICALLY changed in 20 yr
on
Beagle 2 Failure Theories
·
· Score: 2, Informative
how does that mean they had no idea the air was so thin?
As Mars Express closed in on the planet, astronomers noticed a large dust storm building on the planet. Martian storms are unusual in that they markedly heat the atmosphere. As dust particles are swept up into the air, they absorb solar radiation and radiate heat - warming the atmosphere, increasing the force of the wind and so raising more dust. As the air warms, it expands and pressure drops.
All three landers were committed to landing on Mars at a particular time from the moment they blasted off. Unlike Viking, which could sit in orbit and wait for ideal conditions, they had to land directly. The two NASA landers had a larger safety margin and made it to the surface, Beagle 2 had almost none and may simply have landed too fast.
Unfortunately having a stand-off orbiter is expensive in terms of weight and neither the Delta IV nor the Soyuz/Fregat could have sent a useful orbiter and a lander to Mars. The alternative would have been to use the much bigger Titan IV or Proton rockets.
And this isn't the first time a Mars lander has been affected by adverse weather, the Soviet Union's Mars 3 became the first craft to land on Mars in 1971. It touched down in the midst of a dust storm and returned data for only 20 seconds before mysteriously falling silent. The Soviets believed that its antenna had been knocked out of alignment by the storms.
Such an error would just send the poor Beagle 2 hurtling into the vast reaches of space or crashing to the surface. So it is most likely something like this that has caused all the trouble with the Beagle 2 and given those poor Brits such a hard time.
Beagle 2 was released from Mars Express whilst the probe was on a ballistic trajectory and before Mars Express went into orbit (indeed if it hadn't ejected Beagle 2, Mars Express would have been unable to enter orbit).
We know where Mars Express was, we know in what direction it was facing, how fast it was travelling and when Beagle 2 was released. Since the probe had no engines it had to follow a simple path to the surface.
So we can say with absolute confidence that Beagle 2 hit the upper edges of the Martian atmosphere. After that, all else is speculation until some wreckage is found.
Seriously, though, this looks not unlike a typical small commuter car that you might see in Europe every day. The accenting on the headlights is the only thing that stands out.
Is that the new design? It looks identical to the Norwegian Pivco electric car developed about 5 years ago. Ford got into a partnership with Pivco and released the vehicle as the TH!NK in Europe.
AFAIK the Pivco is now out of production. It featured on an excellent Channel 4 programme backed by the Design Council 'Better by Design' where they called in the designer partnership Seymour-Powell. The designers came up with some superb little ideas - electric cars that looked great, micro-delivery vans for small companies that featured removable back sections so the van could be changed to a different purpose in minutes, small cars with easy access for the elderly or for small children, a sporty version.
As you can imagine, there ideas weren't taken up by Pivco.
Now what we need are electric Smart cars - great design, I love the removeable body panels so that you can restyle your car when you get bored of it, but the fuel economy is no better than bigger, cheaper cars. But I have to admit, the Smart Roadster and the Bluewave are gorgeous!
Well, you'd still need an optician. Leaving the lenses tuning to the user could end in a bad regulated lenses or not suitable for that person. Not everyone has common sense or skill for tuning them. This is like automedication.
Is it better for a person living without access - either physical or financial - to an optician to be able to see something, rather than a blur? It's pretty hard to imagine how the myopic amongst us would manage without access to spectacles, contacts and the like.
Here in the UK plenty of charities collect old spectacles for redistribution in the developing World. Personally I imagine the quality of life with improved vision rather than perfect vision must be significant.
I guess that if you fill a plastic bag with water you automatically get a lens which has a () shape, as opposed to the )) shape you normally get in glasses. It might work, but you not gone look like the coolest kid on the bloc wearing two fish-bowls on your nose.
About ten years ago a UK charity demonstrated a pair of spectacles for the developing World that used just this principle. The lens were made of two plastic films separated by a small gap. Syringes filled with water (?) could be attached to the arms of the spectacles. The person needing the glasses would put them on, then the syringes would be depressed and water pushed into the gap between the films. When the wearer saw a sharp image, the syringe could be disconnected.
No need for precision lens grinding technology, no need for a trained optician and most of all cheap to make and replace.
Never saw it again, I guess the curse of 'Tomorrow's World' struck this one down.
I saw that the NASA have launched Deep Space 1 in 1998. This probe flew by the commet Borrelly in 2001, using ion propulsion. As with the recent ESA and NASA mars missions, you can not compare the projects directly -- Deep Space 1 was a high risk project, didn't land, the speed/trajectories of the commets differ, etc -- but it shows the ion drive is certainly an option.
It's amazing that ion propulsion has taken so long to (ahem) take off. The first space craft to use ion thrusters was Zond 2 which flew to Mars in (wait for it) 1964! The craft suffered power failures en-route and lost communications shortly before flying past the planet at a distance of only 1500km. Had it survived, it would have been the second spacecraft to make a close approach to Mars - beaten by one month by the American probe Mariner 4.
The same ion engines were flown in 1965 on an identical spacecraft - Zond 3. It was sent past the Moon, returned some superb images and then flew on into deep space where it retransmitted the images. The Soviets were trying to improve their deep space tracking systems and used Zond 3 as a test bed for future missions.
As far as I know the engines were never flown again. Strange.
Life does not preferentially select carbon-12. Carbon-12 and -13 are chemically indistinguishable. There is no way that a (bio-)chemical mechanism could distinguish between them.
Sorry you're wrong, isotopes are chemically almost identical, but you can separate them using chemical processes. Uranium is routinely enriched using chemical techniques. They may also be separated physically, the heavier isotope tending to have slightly higher boiling points and very slightly lower reactivity. The processes that incorporate carbon into living tissues favour the lighter isotope of carbon over the heavier.
The depletion of carbon 13 in plant tissues is one method of determining nutrient sources for herbivores. Since different groups of plants have slightly different photosynthetic pathways they produce slightly different depletions of carbon 13 (so-called dC13) in their tissues which can be traced through into animal tissue.
And a quick scan of the Beagle 2 page shows that they were trying to get a C12/13 ratio from Mars.
If life did select -12, then radio-carbon dating would simply say that all dead things are exactly the same age.
And why is that, when radiocarbon measures the amount of carbon 14 in a sample?
Since the c-13 decays (known half-life) then the current ratio of c-12 to c-13 implies the time passed between death and now.
Oh dear. carbon 13 is perfectly stable. You're thinking of carbon 14 which no one has even mentioned in this context as yet. C14 dating is hardly ever used in geology because the half-life is too short for all but the most recent of sediments.
Don't be ridiculous. An RTG with twice the power output would have weighed far less than the batteries, solar panels, and mounting.
I couldn't find any bang-up-to-date specs for RTGs, but those fitted to Galileo and Ulysses weighed 65 kilos, which is a sizeable chunk of the rover's 185kg. Don't forget that any rover using an RTG would need a major redesign so as to shed heat during the flight to Mars. It might have required the use of a Titan IV rather than the cheaper, but smaller Delta to get it to Mars.
Of course what we need is someone to approach the Russians about using a Proton to send 4,500kg to Mars - then we could have some serious exploration!
Agree with you completely about the senseless scare stories sent around before the Cassini launch, you'd have thought NASA had a glowing chunk of plutonium mounted on the nose cone.
Slashdot Mirror
There is also an excellent BBC4 documentary called 'By Atom Bomb to the Stars' which has an enormous amount of colour footage of the Orion tests - well worth watching out for.
Best wishes,
Mike.
Thanks for that scary link, all of a sudden Dubya's NMD plan seems almost rational... ALMOST.
Best wishes,
Mike.
There is no mention made of that in the article at all.
Would this be completely unconnected with the Hypersonic Cruise Vehicle (Falcon) concept? DARPA's idea for a global hypersonic bomber that could pre-emptively bomb a country back to stone age before Letterman.
Still, the Germans beat DARPA to this idea by about 60 years - meet the Sanger Amerika bomber... an aircraft that would fly right around the planet skipping off the atmosphere like a stone thrown across a pond.
Best wishes,
Mike.
The Barringer object is estimated at 50-70m in diameter which is about twice the size of the thing whizzing towards us.
Not a bad excuse eh?
Best wishes,
Mike.
If both bodies were the same shape the larger would have eight times the volume.
As for mass, Barringer was definitely iron which makes it comparitively rare - less than 6% of observed meteorite falls are iron, yet they make up over 80% of collected meteorites. The latter number is easy to explain - iron meteorites don't look anything like rocks found on Earth, the much more common stony meteorites (which form over 80% of all observed falls) are very hard to distinguish from the stuff on the ground.
More than likely this is a stony body which would give it a much lower density - round about 3.6 gcm-3 as opposed to 7.9 gcm-3 in iron meteorites.
Having said that - a lump of stone that size hitting the Earth would still be comparable to a hydrogen bomb going off - as you say it would have spoiled a whole lot of people's days.
Best wishes,
Mike.
No he's not.
It depends if it solid rock. many stony asteroids are apparently spongy having once contained volatiles that have subsequently been lost to space. These fragile objects will disintegrate in the atmosphere as atmospheric deceleration crushes them.
Its for this reason that carbonaceous chondrite meteorites - the black ones with the exciting organic compounds are relatively rarer on Earth than their abundance in space would suggest. We're regularly encountering them, they just don't make it through to the surface.
Having said that a 25m chunk of anything disintigrating in the atmosphere would produce a blast in the high kiloton, low megaton range. One of these smashing into a city would be a catastrophe.
And they seem to be more common than we think - there is obviously Tunguska in 1908, but then there are reports of something exploding over the Amazon basin in the 1930s, the more than 100 small impacts that hit Sikhote-Alin in Russia in 1947 and the most recently uncovered biggish impact at Wabar in Saudi Arabia - a Hiroshima-sized explosion in either 1863 or 1891 (there is no agreement on the date, since Arabic scholars saw two bright meteors heading in that direction on different dates, it's only recently that scientists have been able to determine the relative youth of the Wabar craters).
Best wishes,
Mike.
At the risk of committing blasphemy on /. - if you read the article, this is about a probe that will search for life in the ocean deep under the Europan crust.
Best wishes,
Mike.
The surface of Europa is heavily irradiated, but not the underlying ocean. As far as I know no one is suggesting that there is life on the Europan surface.
Best wishes,
Mike.
Except any life on Europa will have evolved away from that radiation since its protected by almost 20km of ice.
The real threat of any contamination from a probe is not so much from radiation as from heavy metals leaching into the environment, but then if the floor of the Europan ocean is anything like the black smokers of Earth's oceans any life should be used to heavy metals.
Best wishes,
Mike.
Best wishes,
Mike.
Not forgetting that if you bought one of the higher end Amigas - 1500/2000/2500/3000/4000 you had the pay for a monitor on top. PC owners got a monitor thrown in with the sticker price which was frequently lower than the Amiga. By the time the 4000 came along - shoehorned into a PC box it looked ridiculously overpriced to all but those people who desperately needed an Amiga.
My 4000 still works, but none of my monitors will synch to its frequency. Sigh - the march of progress.
Best wishes,
Mike.
Apollo is a name given to a class of asteroids - besides since he was associated with the Sun, sticking him out in the darkness wouldn't be fair - and Apollo was not a god you wanted to piss off. :)
Apollo is his Greek name, to the Romans he was Phoebus which I think is still free.
Juno, Diana, Cupido, Minerva, Ceres, Bacchus, Vesta and Flora are all asteroids.
Janus is a Moon of Saturn.
Vulcan was reserved for an intra-Mercurian planet postulated in the 19th Century to explain eccentricities in the orbit of Mercury. It does not however exist.
Proserpine and Maia appear to be free though.
Best wishes,
Mike.
Europa is only kept molten by the tidal forces induced in its orbit around of Jupiter. Its internal heat sources from radioactive decay are far too small to keep the interior hot.
So unless we can find one of these bodies in a tidal relationship there is no prospect of finding life.
Best wishes,
Mike.
Clyde Tombaugh who discovered Pluto performed an exhaustive search for Planet X for several decades. From his results he concluded that there were no undiscovered Jupiter-sized bodies within 470AU of the Sun, and no Neptune-sized objects with 210AU. (Pluto is never more than 50AU from the Sun).
The Oort Cloud is believed to have been populated by planetismals thrown out of the early inner part of the Solar System by the formation of Uranus and Neptune. They would have slungshot smaller bodies into the outer darkness into orbits that match the hypothetical orbits in the Oort Cloud. They would not have been able to shunt anything larger out that far - at least not without disrupting their own formation.
A further problem is that planet formation models run into trouble this far out. Distances between the planetismals that made up the proto-planets would have been so great, and relative velocities so small that its hard to see how they would ever have collided to built up a bigger planet.
Best wishes,
Mike.
Mars Express reported all systems okay in the late November 2003 pre-release check, but I couldn't tell you how many of Beagle 2's systems were given a check-up at that point.
How about the Open University opening the software so that many eyes can see if we can find any bugs?
The descent software was written by Astrium. I'm sure they are just as keen as any defence contractor to let people see their source code. :)
Best wishes,
Mike.
IIRC they tweaked the programming on the second lander following Spirit's descent to the surface and analysing its data. This was the first indication that the pressure was lower than expected.
Either Beagle 2's landing sequence was such that it could not be tweaked en route, or ESA overlooked the opportunity to make such an adjustment.
Beagle 2 could receive software upgrades in-flight, but by the time NASA measured the pressure in the atmosphere, Beagle 2 was long-lost.
Best wishes,
Mike.
As Mars Express closed in on the planet, astronomers noticed a large dust storm building on the planet. Martian storms are unusual in that they markedly heat the atmosphere. As dust particles are swept up into the air, they absorb solar radiation and radiate heat - warming the atmosphere, increasing the force of the wind and so raising more dust. As the air warms, it expands and pressure drops.
All three landers were committed to landing on Mars at a particular time from the moment they blasted off. Unlike Viking, which could sit in orbit and wait for ideal conditions, they had to land directly. The two NASA landers had a larger safety margin and made it to the surface, Beagle 2 had almost none and may simply have landed too fast.
Unfortunately having a stand-off orbiter is expensive in terms of weight and neither the Delta IV nor the Soyuz/Fregat could have sent a useful orbiter and a lander to Mars. The alternative would have been to use the much bigger Titan IV or Proton rockets.
And this isn't the first time a Mars lander has been affected by adverse weather, the Soviet Union's Mars 3 became the first craft to land on Mars in 1971. It touched down in the midst of a dust storm and returned data for only 20 seconds before mysteriously falling silent. The Soviets believed that its antenna had been knocked out of alignment by the storms.
Best wishes,
Mike.
Beagle 2 was released from Mars Express whilst the probe was on a ballistic trajectory and before Mars Express went into orbit (indeed if it hadn't ejected Beagle 2, Mars Express would have been unable to enter orbit).
We know where Mars Express was, we know in what direction it was facing, how fast it was travelling and when Beagle 2 was released. Since the probe had no engines it had to follow a simple path to the surface.
So we can say with absolute confidence that Beagle 2 hit the upper edges of the Martian atmosphere. After that, all else is speculation until some wreckage is found.
Best wishes,
Mike.
Is that the new design? It looks identical to the Norwegian Pivco electric car developed about 5 years ago. Ford got into a partnership with Pivco and released the vehicle as the TH!NK in Europe.
AFAIK the Pivco is now out of production. It featured on an excellent Channel 4 programme backed by the Design Council 'Better by Design' where they called in the designer partnership Seymour-Powell. The designers came up with some superb little ideas - electric cars that looked great, micro-delivery vans for small companies that featured removable back sections so the van could be changed to a different purpose in minutes, small cars with easy access for the elderly or for small children, a sporty version.
As you can imagine, there ideas weren't taken up by Pivco.
Now what we need are electric Smart cars - great design, I love the removeable body panels so that you can restyle your car when you get bored of it, but the fuel economy is no better than bigger, cheaper cars. But I have to admit, the Smart Roadster and the Bluewave are gorgeous!
Best wishes,
Mike.
Is it better for a person living without access - either physical or financial - to an optician to be able to see something, rather than a blur? It's pretty hard to imagine how the myopic amongst us would manage without access to spectacles, contacts and the like.
Here in the UK plenty of charities collect old spectacles for redistribution in the developing World. Personally I imagine the quality of life with improved vision rather than perfect vision must be significant.
Best wishes,
Mike.
About ten years ago a UK charity demonstrated a pair of spectacles for the developing World that used just this principle. The lens were made of two plastic films separated by a small gap. Syringes filled with water (?) could be attached to the arms of the spectacles. The person needing the glasses would put them on, then the syringes would be depressed and water pushed into the gap between the films. When the wearer saw a sharp image, the syringe could be disconnected.
No need for precision lens grinding technology, no need for a trained optician and most of all cheap to make and replace.
Never saw it again, I guess the curse of 'Tomorrow's World' struck this one down.
Best wishes,
Mike.
It's amazing that ion propulsion has taken so long to (ahem) take off. The first space craft to use ion thrusters was Zond 2 which flew to Mars in (wait for it) 1964! The craft suffered power failures en-route and lost communications shortly before flying past the planet at a distance of only 1500km. Had it survived, it would have been the second spacecraft to make a close approach to Mars - beaten by one month by the American probe Mariner 4.
The same ion engines were flown in 1965 on an identical spacecraft - Zond 3. It was sent past the Moon, returned some superb images and then flew on into deep space where it retransmitted the images. The Soviets were trying to improve their deep space tracking systems and used Zond 3 as a test bed for future missions.
As far as I know the engines were never flown again. Strange.
Best wishes,
Mike.
Best wishes,
Mike.
Sorry you're wrong, isotopes are chemically almost identical, but you can separate them using chemical processes. Uranium is routinely enriched using chemical techniques. They may also be separated physically, the heavier isotope tending to have slightly higher boiling points and very slightly lower reactivity. The processes that incorporate carbon into living tissues favour the lighter isotope of carbon over the heavier.
The depletion of carbon 13 in plant tissues is one method of determining nutrient sources for herbivores. Since different groups of plants have slightly different photosynthetic pathways they produce slightly different depletions of carbon 13 (so-called dC13) in their tissues which can be traced through into animal tissue.
And a quick scan of the Beagle 2 page shows that they were trying to get a C12/13 ratio from Mars.
If life did select -12, then radio-carbon dating would simply say that all dead things are exactly the same age.
And why is that, when radiocarbon measures the amount of carbon 14 in a sample?
Since the c-13 decays (known half-life) then the current ratio of c-12 to c-13 implies the time passed between death and now.
Oh dear. carbon 13 is perfectly stable. You're thinking of carbon 14 which no one has even mentioned in this context as yet. C14 dating is hardly ever used in geology because the half-life is too short for all but the most recent of sediments.
Best wishes,
Mike.
I couldn't find any bang-up-to-date specs for RTGs, but those fitted to Galileo and Ulysses weighed 65 kilos, which is a sizeable chunk of the rover's 185kg. Don't forget that any rover using an RTG would need a major redesign so as to shed heat during the flight to Mars. It might have required the use of a Titan IV rather than the cheaper, but smaller Delta to get it to Mars.
Of course what we need is someone to approach the Russians about using a Proton to send 4,500kg to Mars - then we could have some serious exploration!
Agree with you completely about the senseless scare stories sent around before the Cassini launch, you'd have thought NASA had a glowing chunk of plutonium mounted on the nose cone.
Best wishes,
Mike.