Posted by
michael
on from the up-up-and-away dept.
sckienle writes "Space.com has an article about the Israeli X Prize spacecraft. Not a lot of hard technical details, but a good overview of an attempted alternative to standard rocket launches."
-- --
Some days you're the dog; some days you're the hydrant.
Balloon launch
by
dpilot
·
· Score: 3, Interesting
As a kid I remember seeing a picture of one of these from back in the early days of rocketry. The rocket was shooting right up through the balloon, destroying it in the process.
Unless they do some sort of drop first, or an initially oblique launch, I don't see how the Israeli effort can help but do the same. If they drop first, then they have to launch at negative velocity, which negates part of the benefit. If they launch through the balloon with a manned vehicle, they have to make sure they can go cleanly through it without snarling something.
It'll be interesting. I like the idea of getting to 80,000ft without spending reaction mass.
-- The living have better things to do than to continue hating the dead.
Re:Balloon launch
by
geek42
·
· Score: 2, Informative
Looks like they intend to detach first, then fire rockets with the module at an angle of 70 to 80 degrees from horizontal.
http://www.xprize.org/pdfs/ILAT.pdf
Dumb question: do they retrieve the balloon later, or just let it float about up there? How long will it take to come down?
Less dumb question: how do you control where the landing site will be when your initial, 2-3 hour ascent is at the mercy of the wind? I suspect you don't - not my favorite form of transportation, given the landing is supposed to be at 25 km/h (15.5 mph). I can think of plenty of places I _wouldn't_ want to land at that speed, with or without ballutes!
Unless they do some sort of drop first, or an initially oblique launch, I don't see how the Israeli effort can help but do the same. If they drop first, then they have to launch at negative velocity, which negates part of the benefit.
Not much. The main benefit of a balloon launch is that you're above most of the atmosphere, and so have less drag to worry about. Dropping a few hundred metres won't impact that much, and the downwards velocity you gain while falling is truly negligeable compared to the delta-v an orbit-capable rocket needs.
The easiest would be to have a big flamethrower on the front to incinerate the balloon and strings. Both boosters and flamethrower goes off at the same time.
Dropping a few hundred metres won't impact that much, and the downwards velocity you gain while falling is truly negligeable compared to the delta-v an orbit-capable rocket needs.
X-prize rockets are *nowhere near* orbit capable, delta-v around 1400ms-1 compared to 10000ms-1 (just 2% of the kinetic energy!)
X-prize rockets are *nowhere near* orbit capable, delta-v around 1400ms-1 compared to 10000ms-1 (just 2% of the kinetic energy!)
Actually, I calculate it as about 8 km/sec for orbit and about 1.8 km/sec for 100 mile altitude, and about 30 vs. 1.6 MJ/kg (about 5% of the kinetic energy).
It's still negligeable. Gravitational potential energy is proportional to distance travelled vertically, so falling a few hundred metres gives very little kinetic energy compared to the kinetic energy required to travel up 100 miles.
if slashdot allowed mathml we could include maths equations in our comments. how cool would a simple web interface that could do math anonated graphics, could we have a firebird embedded plugin.
Perhaps the balloon could be run teathered? If you could compress enough helium (into tanks) to give it a small negative lift, it wouldn't necessarily take an enormously strong cable to pull it back to the launch pad.
-- "He who would learn astronomy, and other recondite arts, let him go elsewhere. " -- John Calvin, commenting on Genesis 1
That'd be one long-ass tether. If you wanted to avoid taking the full force of the balloon, you'd have to activate your compression system before the manned module separated. That means you'd want a fast compression system, to minimize the impact on the module's altitude.
If you're going to have a tether, though, why not take it a step further: make the tether strong enough to take the full lift of the balloon, and use it to winch up the next module. Sort of a space elevator, but not quite... more of a stratosphere elevator! =)
Would it be possible to put the rocket on the top of the balloon? It's counter-intuitive, but given a large counter-balancing weight below the balloon (much heavier than the spacecraft), it could be possible. Add in some fancy balancing electronics and it's almost starting to sound practical.
It'd be cool to see such a balloon escape the gravitational pull of Earth. You'd have an enormous source of solid propulsion in space if you could keep pressurizing the balloon after it released some of it's helium. Not only that, the balloon could ease re-entry creating a slow descent and not risking burning up the crew.
Could you make the external material some type of radiation barrier? Trips to Mars for instance with the balloon being a solar/radiation shield for the inhabitants?
That is a very interesting idea. I wonder what sort of propulsion would be required once the effectiveness of the balloon 'runs out' in order to get it above the gravity well?
Seems to me if you can float your material into space, then you can float a *lot* of material into space...
-- ; -- the corruption of government starts with its secrets. a truly free people keep no secrets.
--
Re:Space Propulsion? Not quite
by
MerryGoByeBye
·
· Score: 1
Have you ever seen what happens when you put rubber into liquid nitrogen? Now extrapolate that to a few degrees Kelvin and you'll see why this idea (lovely as it might be otherwise) is DOA.
Unfortunately, the thrust created via the explosion would be in the wrong direction.
-- SCO (noun.)- A Slimy Corporate Ogre. Often seeks free money.
Where would they land?
by
Anonymous Coward
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· Score: 0
If they launch from Israel, I wouldn't want to be in the capsule when it lands in country to the east (the direction of the jet stream). Just imagine that they land in Pakistan. They could get out of the capsule and say "Don't shoot, we're Israelis"
To win the $10 million X Prize a spacecraft must be privately financed and constructed with the ability to fly three people 62 miles (100 kilometers) into space. It also must be reusable, flying twice within a two-week period.
They can use no money from the Israeli Gov., whether it be from Israeli or US taxpayers.
Bear in mind that Boeing Civilian Aircraft is not subsidised by the US Gov't... but then they brought their new 767 tankers at 10 times the normal cost.
Airbus is not subsidised by the EU gov'ts... but they get a sizeable loan on good terms for R&D use.
Governments are governments - when they want to fund something, but are not allowed to, they just find another way to pour the cash in.
Re:What would the US reaction be if ...
by
Anonymous Coward
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· Score: 0
I'm not sure what the exact reaction, but I do imagine a senator in the midwest will rename "Persian Rugs" to "Freedom Rugs". That's the just the kind of idiotic country I live in. Now if you'll excuse me, I have to go watch Sean Hannity on Fox News....
What ?!?!?!
by
Anonymous Coward
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· Score: 0
Where have you been for the last 20 years? Israel has more nukes than its arab neighbours put together. Fuck Iraq, fuck Iran and Syria, if anywhere in the Middle East can wipe out the world, it's Israel.
Re:What ?!?!?!
by
Anonymous Coward
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· Score: 0
Sorry but that isn't true! Chemical and biological weapons are just as devastating as nukes and probably more effective considering that it would be foolish to lob a nuke in your back yard.
Plus if such an event was to happen I am sure Pakistan would have a coup deta and give the Israel nice barbecue feast.
Mutual destruction, assures the survival of no one but the politicians.
Re:What ?!?!?!
by
Anonymous Coward
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· Score: 0
Ummm yeah. Anthrax proved to be unstopable here in the U.S. after Sept.11. I'm so relieved "the Terrorists" didn't cheap out and use Nuclear weapons instead of that dreded Anthrax. I even heard of postal workers getting nasty skin rashes. You sir are what we call a fuckin clueless moron.
They should use a hydrogen balloon instead of helium - that way when they ignite the rocket, they'll get extra boost as the balloon explodes.
Except that hydrogen needs oxygen to burn. That's why rocket fuel usually has a lot of oxidizer in it.
By the way- this is the reason the Hindenburg really didn't burn 'because of the hydrogen'; there wasn't enough oxygen(if there had, there would have been a massive explosion- not a huge fire). As mentioned on slashdot among other places, scientists examined the film and noticed lots of black smoke, and lots of visible light; witnesses reported lots of yellow flame. Hydrogen burns cleanly, and generates next to no visible light when it does.
What caused it? Well, maybe the paint on the canopy- which was discovered to have a chemical composition very similar to solid rocket fuel(powdered aluminum, for example, was one ingredient.)
Aww, poor Israel...
by
Anonymous Coward
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· Score: 0
They can't fire nuclear weapons at Iran now, lest they send some back...
Re:About the Israelis
by
Anonymous Coward
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· Score: 0
"Critics of Israel are usually denounced as nazis or terrorists [...]"
You forgot "trolls".
Should I or should'nt I?
by
Anonymous Coward
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· Score: 0
ok everyone all together
JEEEEWWWSSSSS IIINNNN SSSSPPPPPAAAACCCCEEEEEE
Uncle Mell would be proud
It's a Natural Resource
by
Anonymous Coward
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· Score: 0
They should use Suicide Bomber propulsion. Heck, that might get them to Mars.
Re:About the Israelis
by
Anonymous Coward
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· Score: 0
Please watch your language, you're giving Nazi's a bad name. I'd never want to compare the bungling bunch of israeli amateurs with a lean mean fighting machine like the Nazi's where.
If the israelis would've had even 10% of the Nazi's idealism and quality of execution, they would have solved the 'Palestinian problem' a long time ago.
For all our Post-Modern touchy feely sensitivities, the Nazi's did know how to wage war and get rid of ethnic groups they didn;t like.
This is great news!!!
by
Anonymous Coward
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· Score: 0
I can't wait to see my paycheck lessened in the name of Israeli innovation! I mean don't get me wrong, I love it when they use my tax money for building fortress cities and tanks in the name of a racist God, but this just extends the thought of Israeli soon-to-be domination of airspace. Yes, life is great in California:)
Re:About the Israelis
by
Anonymous Coward
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· Score: 0
Sir, that is bollocks.
The Israelis do have ideals - they want complete annhilation of the Palestinian people. Rather blunt, but idealogical enough to count as an idealology. They have the weapons and the ability to do it (not hard, their tanks and helicopter gunships against the Palestinians AK-47s).
Unfortunately, unlike Nazi Germany, the Zionists killed, maimed and massacred for thousands of years for a bit of land that was totally devoid of prosperity. It has no real resource value and it was only really useful for hiding secret nuclear reactors for weapons development.
This combined with the fact the Arabs are being a relentless pain in the arse over to the East meant that the usually greedy and selfish Jews that moved in after the Palestinians were kicked out had *shock* NO MONEY!
This is where America comes in. They usually don't tend to (publically) approve the slaughter of entire ethnic groups, and since the Israelis are dependant on aid from America (after all, that's how they pay for their tanks and helicopter gunships!), they have to keep them happy in that respect. And if they don't, bye-bye Israel!
And thus for that reason they have had to postpone their dream of killing off the Palestinians once and for all, at least for the time being.
Slashdot Mirror
This can be used to carry WMD!!
But wait, they don't have any !!
GO CANADA!!!
c hn icalFlight.html
http://www.davinciproject.com/beta/Technical/Te
GO CANADA!!!
--meh--
As a kid I remember seeing a picture of one of these from back in the early days of rocketry. The rocket was shooting right up through the balloon, destroying it in the process.
Unless they do some sort of drop first, or an initially oblique launch, I don't see how the Israeli effort can help but do the same. If they drop first, then they have to launch at negative velocity, which negates part of the benefit. If they launch through the balloon with a manned vehicle, they have to make sure they can go cleanly through it without snarling something.
It'll be interesting. I like the idea of getting to 80,000ft without spending reaction mass.
The living have better things to do than to continue hating the dead.
Could you make the external material some type of radiation barrier? Trips to Mars for instance with the balloon being a solar/radiation shield for the inhabitants?
All together this is an interesting concept.
Have you ever seen what happens when you put rubber into liquid nitrogen? Now extrapolate that to a few degrees Kelvin and you'll see why this idea (lovely as it might be otherwise) is DOA.
They should use a hydrogen balloon instead of helium - that way when they ignite the rocket, they'll get extra boost as the balloon explodes.
>:-D
(Spudley Strikes Again!)
If they launch from Israel, I wouldn't want to be in the capsule when it lands in country to the east (the direction of the jet stream). Just imagine that they land in Pakistan. They could get out of the capsule and say "Don't shoot, we're Israelis"
They can use no money from the Israeli Gov., whether it be from Israeli or US taxpayers.
Don't Bogart the fish sticks
... It was Iran doing this?
Where have you been for the last 20 years? Israel has more nukes than its arab neighbours put together. Fuck Iraq, fuck Iran and Syria, if anywhere in the Middle East can wipe out the world, it's Israel.
nt
Iran just tested a missile that can reach Israel. Much more war-like than a privately financed rocket with a credible civilian use...
Karma: Excellent (My Karma? I wish...:-( )
They should use a hydrogen balloon instead of helium - that way when they ignite the rocket, they'll get extra boost as the balloon explodes.
Except that hydrogen needs oxygen to burn. That's why rocket fuel usually has a lot of oxidizer in it.
By the way- this is the reason the Hindenburg really didn't burn 'because of the hydrogen'; there wasn't enough oxygen(if there had, there would have been a massive explosion- not a huge fire). As mentioned on slashdot among other places, scientists examined the film and noticed lots of black smoke, and lots of visible light; witnesses reported lots of yellow flame. Hydrogen burns cleanly, and generates next to no visible light when it does.
What caused it? Well, maybe the paint on the canopy- which was discovered to have a chemical composition very similar to solid rocket fuel(powdered aluminum, for example, was one ingredient.)
Please help metamoderate.
They can't fire nuclear weapons at Iran now, lest they send some back...
"Critics of Israel are usually denounced as nazis or terrorists [...]"
You forgot "trolls".
ok everyone all together
JEEEEWWWSSSSS IIINNNN SSSSPPPPPAAAACCCCEEEEEE
Uncle Mell would be proud
They should use Suicide Bomber propulsion. Heck, that might get them to Mars.
Please watch your language, you're giving Nazi's a bad name. I'd never want to compare the bungling bunch of israeli amateurs with a lean mean fighting machine like the Nazi's where.
If the israelis would've had even 10% of the Nazi's idealism and quality of execution, they would have solved the 'Palestinian problem' a long time ago.
For all our Post-Modern touchy feely sensitivities, the Nazi's did know how to wage war and get rid of ethnic groups they didn;t like.
I can't wait to see my paycheck lessened in the name of Israeli innovation! I mean don't get me wrong, I love it when they use my tax money for building fortress cities and tanks in the name of a racist God, but this just extends the thought of Israeli soon-to-be domination of airspace. Yes, life is great in California:)
Sir, that is bollocks.
The Israelis do have ideals - they want complete annhilation of the Palestinian people. Rather blunt, but idealogical enough to count as an idealology. They have the weapons and the ability to do it (not hard, their tanks and helicopter gunships against the Palestinians AK-47s).
Unfortunately, unlike Nazi Germany, the Zionists killed, maimed and massacred for thousands of years for a bit of land that was totally devoid of prosperity. It has no real resource value and it was only really useful for hiding secret nuclear reactors for weapons development.
This combined with the fact the Arabs are being a relentless pain in the arse over to the East meant that the usually greedy and selfish Jews that moved in after the Palestinians were kicked out had *shock* NO MONEY!
This is where America comes in. They usually don't tend to (publically) approve the slaughter of entire ethnic groups, and since the Israelis are dependant on aid from America (after all, that's how they pay for their tanks and helicopter gunships!), they have to keep them happy in that respect. And if they don't, bye-bye Israel!
And thus for that reason they have had to postpone their dream of killing off the Palestinians once and for all, at least for the time being.
All the best!