Slashdot Mirror

I suspect this was probably discussed in Slashdot back in the day, but couldn't get the search engines to give me a good reference.

This timeline gives the birth of stars at occuring roughly 1 billion years after the big bang, which this article in January gives at between 11.2 and 20 billion years ago...

Wouldn't this hole place a lower limit of 14 billion years on the bang? And if last year's Hubble estimate of 13-14 billion years ago for the bang is right, wouldn't it pin it AT 14 billion years ago?

-T

Just curious where you found that information I can't seem to find any reference to NASA shuttle launches emitting any CO2. Considering their rocket fuel is liquid hydrogen an oxygen, water vapor is about all the engines ought to leave behind.

Well, there's the small matter of having a pair of the world's largest solid fuel rockets strapped to the whole contraption as it climbes skyward.

Otherwise, you're partially right. It'd be good if water wapor was indeed the only way to combine oxygen and hydrogen, but unfortunately the high temperatures involved will give rise to some H2O2 (Hydrogen peroxide). I seem to remember another, but cannot recall it now.

Sun's Output Increasing in Possible Trend Fueling Global Warming

And another:

NASA Study Finds Increasing Solar Trend That Can Change Climate

FYI the US spy satellite range is the Keyhole Series. Has been taking pictures of our earth for more than 30 years.

Tho a lot isnt know about current generation (or even the past 2 generations), the US has released older footage.

The following links have graphs and images. Here and here.

Marklar is the language from South Park from the episode of Starvin' Marvin in Space.

May your Marklar be Marklar. We should Marklar Marklar so we are never confused with Marklar. Marklar is the best Marklar ever, and may Marklar be with Marklar.

Thank you very Marklar!

• http://www.space.com/news/eu_gps_020326.html.
  
• http://www.ucis.pitt.edu/cwes/EUC/EUC_Research/Pol itics_of_Galileo/politics_of_galileo.html
  
• http://www.galileosworld.com/galileosworld/
  
• http://www.state.gov/r/pa/prs/ps/2002/8673.htm
  
• GPS http://ifen1.bauv.unibw-muenchen.de/Lehre/External /SpaceTech/GPS.pdf.
  

These links are from a file I have of info on Galileo. Hopefully no link rot.

There is also an article here.

Besides MSNBC, other medias are *revisiting* the SETI@home project. Read for instance this Space.com article, published yesterday (March 10, 2003). Tariq Malik wrote: "Researchers spearheading a worldwide effort to find ET, or anyone else out in space besides us humans, plan to revisit a group of their most likely candidate radio signals using the world's largest radio telescope." He added that "the Arecibo Observatory will work for three and a half days, starting March 18, to revisit the candidate signals identified by SETI@home users."

Ouch, you're absolutely right.

Very cool...

Heh - the rest of the solar system isn't 1% of the Sun's size! The Sun contains more than 99.8% of the total mass of the Solar System with Jupiter making up most of what's left. - source.

But doesn't it [Ceres] have a satellite? -- and -- What would we qualifty that as, because a satellite must orbit a planet.

It doesn't appear that Ceres has any satellites. But, there are 31 asteroids that do! That doesn't make them planets though...they're just small asteroids with really small moons.

Can anyone remind me what that sequence of numbers is called that vaguely predicts the distances of planets from the Sun?

Yep, its the Titius-Bode Law. Ceres does fit into this. But the reason we don't have a planet in between Mars and Jupiter is because "many astronomers think the asteroid belt is where a planet tried to form, but was pulled apart before it could solidify, caught between the strong opposing tugs of Jupiter and the sun's gravity." Quote taken from here.

Why does a planet _have_ to be a shpere...How perfect a sphere?

Well.... Ceres's shape is too distorted. Its shape is not spherical enough to be like regular planets. And, to get really technical, no planet is really a sphere. Due to rotation, all planets have a slightly distorted shape.

Accoding to this article from NASA, Ion engines don't create anything near 1g of thrust. In fact, the acceleration is so slight that scientists have to test in a vacuum to measure it. Like you mentioned, they get their efficiency from the speed of the ejected ions, however this article states that 80 kg of fuel would last 1 to 2 years and could accelerate a rocket up to 22,000 mph.

And for propellantless propulsion we have the space tether, solar sails, and (for a good laugh) vacuum propellers which are big props that are supposed to push against the 'quantum vacuum'.

No, actually, we are going to Pluto. Pluto is about 6 billion kilometers (or is that 6 trillion meters ?) away. The moon is about 384,400 kilometers away. You do the math.

Oh, and if I recall correctly, we should get there before Pluto's atmosphere completely freezes. If someone else goes 40 - 50 years later, it will be far less usefull from a scientific standpoint.

Either way, good luck to Europe, China, Japan, and anyone else with a space program. I'm interested in all of them, as any one of them, including the US, seems to move at a glacial pace. Now if only someone would start a permanent colony somewhere. That would be a new accomplishment worthy of history books.

Dean G.

The remote control operator can see (immediately with his own eyes) the results of his controls, and only pause maybe every 30 seconds to verify that the experiment out in space has performed similarly.

For experiments where zero-G is important, perhaps a ride on the "vomit comet" is in order. Maybe not, since this article tells me that the plane was retired in '95, and was donated to the city of Houston in May 2000. I'm sure there's a replacement though.

Is there something fundamentally flawed with my idea?

It's hard to pin the "down on space" tail on Bush. Especially when he's talking about building nuclear powered interplanetary exploration craft that will use ion impulse engines and magnetic shielding for ultra-high energy transfer flights to Mars taking weeks rather than months.

I did some testing, and found that if we are successful in building a ship that can sustain 1 g of acceleration over six days (Prometheus calls for constant thrust to keep astronauts under 1 g of gravity to maintain bone and muscle mass, so it could go a hell of a lot faster), I can send a manned mission to Neptune that will take 40 days to get there. This trip would take 14 years on a Hohmann transfer.

Helium 3. 'Nuff said

Presumably when they talk about "mining the moon" they are talking about going there to mine Helium 3. This is an isotope of helium which, if available in abundance, would be a perfect fuel for clean fusion power generation. Unfortunately it is very rare on Earth, but there's plenty on the moon.

I've read about nuclear-explosion-powered space ships before. Project Orion, in the '60s, was a serious attempt at this. google for more links.

It's really amazing to me that the question is even arising; take a look at the archived project page for the Delta Clipper ; this is such an obvious solution, low cost, high sustainability, and it's really cool. Aside from the blowing up thing, of course.

While they claim that the X-series they are currently working on is just the latest incarnation, that's a bunch of crap; the big contractor corps just don't like the idea of a cheap spacecraft.

It's either this or Prometheus; anything else is just a temporary solution.

That, and Bush talked about Project Prometheus in his State of the Union Address. It seems like Bush wants to be remembered for something more than just Iraq.

--sex

You CANNOT fit a 100 foot dish to a satellite and orbit it around Mars or Jupiter, etc, to pick up signals from further out and relay them to earth. Its simply not possible.

Perhaps this is only not possible by conventional thinking, if even then. But picture the Space Elevator hoisting up a large dish, or several small pieces of it. Beyond that, if we can launch an International Space Station that weighs 393,733 lbs, then even a dish factory in space is fathomable. ("Break your satellite? Need new parts? Just order on the universe wide web at uww.spaceparts.com!")

Sounds like you have little faith in NASA, it's engineers and astronauts. Much COULD HAVE been done if a proper debris analysis, ground and space photos etc. confirmed the likelihood of a disaster. Atlantis was on the pad ready to launch within 1 week for a rescue mission. I believe NASA is a CAN DO agency, and when I hear NOTHING COULD BE DONE and we can't do this and we can't do that, I think we sell NASA short. If you don't believe me, check here which states:

"Could another shuttle have been sent up? Shuttle Atlantis might have been rushed into service, and if normal testing were skipped, it might have been in space in a week or so. The Columbia crew had enough supplies to last through Wednesday, Feb. 5 and might have been able to stretch those supplies a few more days."

The Roche limit for non-rotating spherical icy bodies >40 km in diameter approaching the sun is ~1.1 billion meters, and does NOT depend on size. NEAT never got closer than 15 billion meters (according to this article). Even if NEAT was much larger than it actually is, it was immune to tidal breakup.

http://slashdot.org/article.pl?sid=00/07/25/163522 8&mode=thread

Force Fields And Plasma Shields Get Closer
Posted by timothy on 03:23 AM July 26th, 2000
from the use-half-power-for-melting-butter dept.


http://www.space.com/businesstechnology/technology /cold_plasma_000724.html

Some theorists have speculated about mirror matter. This hypothetical stuff is exactly like ordinary matter but only interacts with ordinary matter gravitationally. They theorize that comets disappear because they are a thin matrix of ordinary molecules gravitationally bound to a large mirror object (perhaps a mirror asteroid in the mirror universe). The sun drives off the ordinary stuff, but the mirror object goes unchecked. I'm not making it up!

Last year, an asteroid 100 yards across, passed by the earth unnoticed until three days later. Keep in mind that three year's notice is long enough for the earth to circle the sun three times.

I doubt that "[t]he issue [of killer asteroid censorship] may be making its rounds because an asteroid was discovered orbiting the sun between Venus and Earth earlier this week." As was made quite clear in the link, this asteroid will remain harmless for the rest of its life, unless aliens strap a nuclear rocket to it, or space-monkeys attach a 1000 km solar sail to it, and heave it out of its low energy orbit.

At least they've got something for the weird people with a hand fetish...

To develop the technology quickly, StarTiger was created by the ESA. The project brought a group of researchers together for a few months, provided ample money and facilities, and encouraged development of new technology in a short period of time. The researchers started in June, created their first T-ray image last fall, and released one this week.

http://www.space.com/businesstechnology/technology /t-ray_camera_020613.html

Tethers ( 1, 2, 3 ) attached to counterweights can be used to transfer spacecraft from one orbit to another. The first tether has an orbit that skims the atmosphere, where a craft catches and connects to the end of the tether. The craft is lifted into low earth orbit and subsequent tethers help it to reach escape velocity. Using the tethers takes energy out of the orbits of the counterweights, some of which can be put back by using the tethers for descent as well as launch.

J. Storrs-Hall (once moderator of sci.nanotech) envisioned a space dock, a linear motor suspended 100 km above the ground that accelerates spacecraft to an elliptical orbit. He computes an amortized cost of reaching low earth orbit of 42 cents per kilogram. From the elliptical orbit, it's a relatively small safe step to escape velocity.

A space elevator ( 1, 2 ) is an excellent long-term solution. A cable is hung from a weight in geosynchronous orbit, reaching down to the Earth's surface. The elevator climbs the cable, carrying a craft. When it reaches GEO, the craft detaches and spends only a little fuel getting to escape velocity.

Tethers and the space elevator require novel materials for strong cables, probably using carbon nanotubes. The frame to hold up the space dock is in compression, and something we could build with little or no advance in material science. Any of these alternatives would be vastly cheaper and vastly safer than putting human lives on the noses of fuel tanks subjected to unreasonable speeds and stresses.

Tethers ( 1, 2, 3 ) attached to counterweights can be used to transfer spacecraft from one orbit to another. The first tether has an orbit that skims the atmosphere, where a craft catches and connects to the end of the tether. The craft is lifted into low earth orbit and subsequent tethers help it to reach escape velocity. Using the tethers takes energy out of the orbits of the counterweights, some of which can be put back by using the tethers for descent as well as launch.

J. Storrs-Hall (once moderator of sci.nanotech) envisioned a space dock, a linear motor suspended 100 km above the ground that accelerates spacecraft to an elliptical orbit. He computes an amortized cost of reaching low earth orbit of 42 cents per kilogram. From the elliptical orbit, it's a relatively small safe step to escape velocity.

A space elevator ( 1, 2 ) is an excellent long-term solution. A cable is hung from a weight in geosynchronous orbit, reaching down to the Earth's surface. The elevator climbs the cable, carrying a craft. When it reaches GEO, the craft detaches and spends only a little fuel getting to escape velocity.

Tethers and the space elevator require novel materials for strong cables, probably using carbon nanotubes. The frame to hold up the space dock is in compression, and something we could build with little or no advance in material science. Any of these alternatives would be vastly cheaper and vastly safer than putting human lives on the noses of fuel tanks subjected to unreasonable speeds and stresses.

Mars exploration is a thought, at least it's dramatic enough that it might grab people's attention. I submit that we would be better off pursuing a goal in space with some obvious practical benefit, e.g. this scheme of Robert Kennedy of the Ultimax Group:

Mirrors & Smoke: Ameliorating Climate Change with Giant Solar Sails;

Topic: Mirrors & Smoke, and Other Shady Schemes

390,000 sq.km of solar sails, placed in non-Keplerian orbits around the Sun-Earth L1 Lagrange point, can intercept enough (~0.25%) sunlight to offset global warming and concomitant rapid climate change due to anthropogenic CO2, or if you will, a mirrored Maunder Minimum. Such mirrors can also provide total planetary electricity demand, estimated at 300 quads (quadrillion BTUs) by 2050, displacing all terrestrial carbon-burners.

Bright Future for Solar Power Satellites

A new spaceplane, designed for crew. See the Orbital Space Plane.

A new technology, reusable launch vehicle. See the Space Launch Initiative.

Continuing with the Prometheus Project. We fucked up when we stopped persuing NERVA/Rover.

Mars. Need I say more?

I'd also like to see a space elevator persued, but I don't know that we have the tech yet. Then again, I haven't looked into it that much either.

Yeah, so that's my wishlist. Only a few hundreds of billions of dollars in imaginary cash NASA doesn't have...

from: http://www.space.com/news/spaceagencies/esa_25year s_000602.html
However, ESA's biggest achievement of all, explained Bonacina, lies not in any one particular space project. Rather, it's the fact that 15 European nations have successfully worked together, and in cooperation with other non-European space programs, to reach a common goal.

It's amazing how little a program this wide in scope accomplishes :)

Hmm. Right. And I suppose that telescopes haven't changed much over the last 5 years? Adaptive optics have seen no improvements?

OK, I see where you're coming from.

I'm still not sure that it would have made good financial sense to send four up at once -- only because you make some assumptions that may not be 100% reliable.

Given the ~15-year lifespan of the HST, there may be a chance that regardless of use, the telescope(s) may deteriorate in space (see this semi-related article) and require regular service as part of the design. This, however, is speculation -- there's a good chance that you know far more about this than I do.

Your argument is very compelling, but I'm not totally convinced. But it does raise some very interesting questions for me.

Why would NASA use the Shuttle to deploy the HST if it wasn't necessary? Was it done just to draw more attention to the project? Would it have been cost effective to have built another (in lieu of reparing the original) and launch it via an unmanned rocket? right after the reiaprs, the HST began making new scientific discoveries. After weighing in the time necessary for a redesign/rebuild/unmanned-launch against the scientific findings that happened in the (potential) time saved by the manned repair mission, did we benefit or lose in the end?

Just some stuff that's left in the back of my mind...thanks for the info...very intriguing.

--Turkey

Ever handled the tile material? I have. They had a neat demonstration where they heated a cube of it cherry-red with a torch and then handed it around a moment later. Incredible material, light and essentially fireproof.

But also brittle and fragile as hell, comparable to styrofoam or balsa wood. I've handled this stuff and it would have been trivial to damage with my bare hands. Armor against a blowtorch, but not a pebble.

NASA apparently has had a number of incidents involving damage to the belly of the orbiter from separated insulation and ice on launch. Apparently the polyurethane (or whatever it is) can become ice-impregnated, too, with the hardness of a brick. The report I read reported that on one occasion 300 tiles were damaged beyond repair, and that tiles had been sliced as deep as 1 1/2" out of 2" -- "enough" for re-entry, but there's always the next time. Perhaps Columbia was that next time and your random chance came up.

There have only been a bit over 100 missions, and the composition of the foam has changed over time -- perhaps also the tiles? Yes, the Shuttle was designed for brutal re-entry, but not to HIT anything at supersonic speeds. The tile would be destroyed by mere rain. Apollo by contrast launched in just about anything. Apollo 12 even survived a lightning strike (barely -- the capsule guidance system was scrambled, which would have led to a breakup of the launch vehicle had it not had its own redundant guidance).

I'm unwilling to draw any conclusions this early, but the damaged-tile theory is plausible. If we're lucky we'll recover that wing.

The Space Exploration Act of 2002 seemed a great first step, but received very little backing. NASA's NExT group plans look very promising - but do they have any money, even in this year's budget? The goal should be human exploration, development, and settlement of the solar system. The National Space Society has a clear roadmap for space development, and a vision of people living and working in thriving communities in space - but membership there has been dropping for years. The goals actually are pretty obvious - what's needed is for the public to get behind them. Go join these organizations, write your senators and congressman! If you care about space, do something about it!

Actually, that much (and more) is denied you, because you obviously know nothing about it and choose to spout off anyway. Quote from space.com article: "Ice forms on the tank because of the super-cold liquid hydrogen and oxygen inside." --Paul Fischbeck, an engineering professor at Carnegie Mellon University who conducted the 1994 analysis.
You sound like every other conspiracy theorist* here. Short on knowledge, but long on theory.

*conspiracy theorists are often control freaks who can't stand the thought that something might happen beyond their (or someone else's) control. The idea that we're fallible, or that circumstances can be such that Bad Things happen despite all attempts to prevent them is inconceivable to them. No, there's no way a single, very lucky and very skilled nut could've killed Kennedy, it was a CONSPIRACY. Yeah, if that makes you feel better, go ahead and think it. But in reality, there are some things beyond our (or others) control...{/rant]

Yes - the space shuttle was travelling fast. But the insulation fell OFF THE SHUTTLE.

Wrong:

Insulation that fell off and hit the shuttle is from the external tanks that are jetisoned after launch. Chunks fell off while shuttle was traveling at approxiamately 2x the speed of sound.

http://www.space.com/missionlaunches/columbia_ques tions_answers.html#foam

So what has happened to all these great ideas? Stifled (so far) for lack of public support! Write your senators and representatives - tell them you believe NASA needs a clear new mission! It doesn't require much or any increased funding - it just needs to get NASA up out of the pork-barrel mire it's been stuck in by Congress for the past 30 years!

because the O-rings in its solid-fuel boosters leaked

because the boosters are made in two pieces

because the boosters have to be transported by rail and barge

because the boosters are manufactured in Utah

because the money to run the Shuttle has to be sprinkled across as many Congressional districts as possible (see here and here, especially the list of subcontractors at the bottom of the second one).

Before Challenger, the Air Force was planning to have a Shuttle fleet of its own, operating out of Vandenberg AFB. The Air Force Shuttle's boosters were going to be made all in one piece, on site, and would have been stronger and lighter than the reusable Shuttle SRBs, allowing more payload to orbit. They wouldn't have been reusable, but I doubt they would have been a lot more expensive when you factor in the costs of recycling SRBs (recovery, transport to and from Utah and refurbishing).

As usual, when you show Congress an engineering versus safety decision, it will choose the option that spends the most money in the most districts.

Hell, they made TANG, can't they think of something new in the 30 years since they designed the Shuttle?

Such a personal reentry vehicle has already been considered. In the 1960's General Electric drew up plans for just such a device, entitled MOOSE (Man Out of Space Easiest), which would have required an astronaut to slip inside a big, foam-filled plastic bag, float out of the spacecraft and fire thrusters attached to the bag to push it out of orbit.

Then, the astronaut would rely on a built-in heat shield to survive the fiery plunge through Earth's atmosphere and wait for a parachute to automatically deploy for a safe landing.

You can check out this out-there but admittedly cool idea at Space.com. I'm still waiting for it to be used in a major motion picture...

For what it's worth, I feel rather strongly that we need to solve the cost-to-orbit problem first - which will then make all the other science cheaper. The beanstalk idea is a good one, but I don't know if it will be viable in the next ten years, so one might also look at the old "National AeroSpace Plane" concept. The concept will work - if congress will fund it. Reducing the complexity of getting to orbit is the ONLY thing that will prevent another shuttle disaster. Its a 30 year old design now; we can do better.

"NASA did not attempt to examine Columbia's left wing with high-powered telescopes on the ground, 180 miles below, or with spy satellites. The last time NASA tried that, to check Discovery's drag-chute compartment during John Glenn's shuttle flight in 1998, the pictures were of little use, [shuttle program manager Ron] Dittemore said. Besides, he said, `'there was zero we could have done about it.' "

The article discusses other options and why they wouldn't have worked. Recommended reading....