

Fly To Mars In A Plastic Ship 234
saskboy writes "NASA reports that an old polymer may be the spaceship material of the future. Polyethylene is in household garbage bags, and it is also an effective solar radiation shield. I learned three years ago in astronomy class that polyethylene is used in the sleeping quarters on current orbiting space vehicles, but now NASA has developed a way to toughen the polymer into a product they call RXF1 which is 'even stronger and lighter than aluminum'. As you may know, radiation in space is currently a major obstacle to manned missions outside of the Earth's magnetic field, so better radiation shielding is essential to planned manned missions to Mars and beyond.
Get the mp3 podcast of the article here."
Plastic aluminum? (Score:5, Funny)
Is it transparent?? Plastic usually is/can be. Perhaps this is what they really meant by transparent aluminum. We should really make sure none of this time's whales have been recently stolen!
Why, no I didn't read tfa.
Re:Plastic aluminum? (Score:2)
Especially since it doesn't yet handle temperature very well. Hmm.. not a good material for a spaceship, I'm thinking.
Re:Plastic aluminum? (Score:2)
Re:Plastic aluminum? (Score:2, Interesting)
If I were designing that thing, I'd put a space between metal shell and plastic - then you have insulation (or a thermos - open the valve in space to evacuate. :-))
Re:Plastic aluminum? (Score:2)
Wrong order dude. The light weight shielding has to be on the outside or you miss the point. Sure there will be some of the very energetic particles that penetrate the outer hull but the vast majority of the particles will produce the secondaries in the outer hull, therefore the low-Z material must be on the outside (to get the desired effect).
Re:Plastic aluminum? (Score:3, Interesting)
Polyethylene is in household garbage bags, and it is also an effective solar radiation shield
No, it isn't. It's an effective GCR shield, not an effective solar radiation shield - for solar radiation, you want high Z.
Would you, perchance, have seen a study that actually for once addresses bremsstrahlung doses with more than a passing menti
Re:Plastic aluminum? (Score:2, Insightful)
Re:Plastic aluminum? (Score:2)
If that's something that would satisfy you as "transparent aluminum", then pigmentation in the current version shouldn't disqualify it.
Not likely (Score:2, Insightful)
I would guess that their new form of PE is a variant on long linear PE, with reduced branching of the CH2 ba
Re:Plastic aluminum? (Score:2)
Re:Plastic aluminum? (Score:3, Informative)
Re:Plastic aluminum? (Score:2)
I want to say one word to you. Just one word. (Score:5, Funny)
if you didn't get this... (Score:3, Informative)
If you haven't seen the movie, shame on you.
Re:I want to say one word to you. Just one word. (Score:2)
Re:I want to say one word to you. Just one word. (Score:2)
...and when the mission is over (Score:5, Funny)
a new fashion (Score:5, Funny)
Yeah, and polyester hats should be much more fashionable than the tin foil ones.
Re:a new fashion (Score:2)
Gotta double up! (Score:2)
You can never be too safe.
Metals are becoming obsolete (Score:3, Interesting)
Re:Nature's way... (Score:5, Informative)
But most architecture just isn't that sensitive to weight. For example, steel frame houses have significant earthquake resistance and are just more durable overall. Most bridges cover modest spans and can continue to be steel and concrete. Further one has to consider the problem of wind force. If your structure is very light for its surface area, then it'll experience increased jostling due to wind. Then you need to engineer some sort of means for stabalizing the structure, maybe guy ropes or some sort of internal computer-controlled weight that counters these motions.
I suspect not. (Score:2, Informative)
This is not true for composites. Acc
Re:I suspect not. (Score:3, Informative)
You may suspect that - but you'd be wrong.
But what's the point? (Score:2, Interesting)
The risk? (Score:4, Insightful)
There is no risk to you.
Nobody is asking you to go to Mars and it just so happens that some people still have the spirit of exploration and adventure and will volunteer to go knowing the dangers involved. (I know this to be true because I would raise my hand for the chance).
If America can't find someone to volunteer and do it for the spirit of exploration, China, a few years later will order someone to do it for prestige.
Re:The risk? (Score:2)
I would cut off my hand for the chance!
Re:The risk? (Score:2)
It's not kindness that makes them concerned about radiation damage. It's practicality.
People smart enough to handle the job are valuable enough to keep healthy. People who aren't, aren't.
Nothing personal intended here. It's just that few people know the effects of radiation as well as the government -- it's not ju
Re:The risk? (Score:2)
Re:The risk? (Score:2)
how about medical care on long missions?
see, they have the need to carry as little as they can with them. that means not a lot of bulky food and not a lot of medical equipment.
space exploration, any exploration for that matter, pushes human technology to the breaking point and forces us to come up with new ways to meet our needs. After our needs are met, the travel becomes easy for everyone to do.
Human space exploration
Re:But what's the point? (Score:5, Insightful)
We desperately need to get some competition going on in space exploration or nothing's going to get done. Come on China...
Re:But what's the point? (Score:5, Insightful)
That being said, we need to go somewhere other than earth orbit. If we keep going on into the future without looking at ways to live without earth we will be doomed to eventually perish here. The planet keeps getting smaller and smaller and the population keeps increasing. Eventually in the relatively near future we will either die en masse from starvation, lack of resources, etc, and (hopefully) leave some survivors, but we could easily become extinct as well. Technology is only going to help us now. If such a mass extinction of humans occurs they will have little fertile land to live off of and very few animals to hunt. We need to kick ourselves out of the womb before we as a race die like a stillborn fetus.
The mother can only sustain our greed for consumption of natural resources for so long.
Re:But what's the point? (Score:2)
> for humanity to marvel at for a long time into the future,
> the actual scientific value of such a mission when compared
> to its cost is greatly diminished.
What about its financial value? I may be remembering wrong, but I thought the Apollo program paid for itself when you count revenue from inventions like velcro, Tang, and the myriad other materials and gadgetry (not to mention stimulting the nascent computer industry). IIRC the
Re:But what's the point? (Score:2)
Actually go there.
What if all the great explorers throughout history simply sent robots (assuming they had them). We'd all be living in isolated tribes sleeping in huts.
Humans (for good and bad) physically explore.
We go places.
Send all the probes and robots you want, but if there is a rock big enough to land on and explore in our solar system my bet is that we will eventually go there.
At the moment space exploration is
Robots should go first .. (Score:2)
Re:But what's the point? (Score:2)
Re:But what's the point? (Score:2)
Re:But what's the point? (Score:2)
Re:But what's the point? (Score:2)
the asgard are not going to help us out on that one.
Everything (Score:2)
Every new robot sent is going to get increasingly fewer returns. What a human can do is - anything. They can climb down in a gully we want to go to now, without spending a few billion more on a craft that MIGHT make it to the surface. Just because NASA has had a lot of success does not mean each new robot is assured of a landing, and once there will not break - especially if you are going in a canyon (when you can easily slip or loose signa
Re:But what's the point? (Score:2)
Nasa (Score:4, Interesting)
Re:Nasa (Score:2)
Won't you think of the baby Jesus?
Re:Nasa (Score:5, Informative)
Erm, where did you get that info from? Bush does many shitty things, but cutting NASA funding isn't one of them. In fact, NASA is one of the few non-defense government agencies which has actually seen funding increases. Bush even threatened to veto [msn.com] a huge appropriations bill unless legislators increased NASA's funding by a billion dollars.
The official info on NASA's budget can be seen here [nasa.gov].
Re:that's the problem (Score:2)
Boeing and Lockheed's NASA take is rather small compared to the tens
Yes, but... (Score:2, Redundant)
Yeah, but really geeks want to know, is it transparent?
So... (Score:2)
Outgassing and thermal properties (Score:5, Insightful)
The history of material science is the history of failures such as the catastrophic failure discovered in Liberty ship hulls in cold North Atlantic waters (learning that some steel alloys are brittle in low temperatures) [disastercity.com] to the Comet airplane crashes (learning that aluminum fatigues from repeat cycles of stress) [wikipedia.org]. I can only hope that NASA does something like LDEF [nasa.gov] with this material before depending on it to hold its properties for several years of space-exposure.
Re:Outgassing and thermal properties (Score:2)
No, sorry, can't say I have. I don't know the properties of cars left up on blocks in the front yard, either.
Re:Outgassing and thermal properties (Score:4, Informative)
The standard for testing whether steels are brittle at low temperatures that we use today was known about and insisted upon by Lloyds of London in the 1930s - it was just taking shortcuts and a two year refusal to acknowledge that there was a problem that resulted in so many of the "liberty" and "victory" ships having problems. Some ships developed major cracks but were kept afloat - since the crack started at hatch corners on deck. One ship used in Antarctic waters in the 1950s developed a crack that opened up to well over a foot across each time the ship went over a large wave in a storm. The ship made it back to port when the crew drilled holes in the deck and bolted steel beams over the crack to hold the deck together. Since these were welded ships they were effectiveley one peice of metal, so a crack starting on deck could go all of the way around to the keel, which is why some of the ships broke completely in half.
Having square sharp cornered windows did the same thing with the Comet airliner - they also failed due to metal fatigue starting from a stress concentration. In the case of the airliner the fatigue properties of Aluminium (yes, americans spell it differently) were not considered to be important enough in the design process.
Back to polyethelene - the effects of radiation on this material are very well known. Despite years of research the best material for some parts of artificial knee joints remains the polyethelene exposed to radiation to produce more cross-links that was developed in the 1950s.
Re:Outgassing and thermal properties (Score:2)
Re:Outgassing and thermal properties (Score:5, Insightful)
This statement simplifies the problem to the point of being incorrect. I don't profess to have nearly the wealth of knowledge as the parent poster, but I have recently read and recommend The Outlaw Sea by William Langewiesche, which examines the modern merchant marine in fascinating detail.
Strength of materials or maintenance procedures has basically nothing to do with the loss of merchant ships in modern times, except for the banal observation that both are involved when a ship sinks. So is water. The cause is closer to deregulation and an unchecked free market in the shipping industry.
I don't think that a NASA-developed plastic space ship is going to experience deregulation or rampant capitalism. It seems pretty likely to me that someone is going to, oh, I don't know, check to see if the material is suitable for use in space before building a space craft from it. Just tossing that out there. By Slashdot standards, I'm probably insightful.
Re:Outgassing and thermal properties (Score:2)
Re:Outgassing and thermal properties (Score:2)
Cool, now I'm a rocket scientist... (Score:2)
I'm off to send my CV to NASA... now where are my crayons?
melting point of polyethelene? (Score:2)
what's the melting point of the modified polyethelene? that would certainly bear into my deciding whetheer to make a space hull from the material.
Re:melting point of polyethelene? (Score:2)
Re:melting point of polyethelene? (Score:2)
In space you only lose heat through radiation which is much slower than the other methods. Unless you have a leak or something that acts as an evaporation point to leach the heat away.
Re:melting point of polyethelene? (Score:2)
Anyhoo, plastic spacecraft is 'almost' old hat. http://www.bigelowaerospace.com/ [bigelowaerospace.com]
Re:melting point of polyethelene? (Score:2)
asuming your ship is roundish and has roughly similar albedo to earth, if you rotate it, it will reach somewhere near the average temperature of earth in our local neihborhood.
One could even paint one half white and one half black any vary the rate of rotation to heat up or cool down the craft as appropriate. you wouldn't even need to use any reaction mass as once you are up to spee
Re:melting point of polyethelene? (Score:2)
Polyethylene (Score:5, Interesting)
According to MatWeb [matweb.com], Ultra High Molecular Weight Polyethylene (UHMW-PE) has an ultimate tensile strength of about 40 MPa [matweb.com], while 7075 alloy aluminum has an ultimate tensile strength of 524 MPa [matweb.com]. The article claims that this new PE-derived material has a tensile strength 3x that of aluminum. I find a 40x improvement in tensile strength a bit tough to believe.
Re:Polyethylene (Score:2)
I for one... (Score:2, Redundant)
Plastic Kits (Score:3, Funny)
Let's Build Something More Useful (Score:2)
It would be more useful to be building cars out of this.
Re:Let's Build Something More Useful (Score:2)
Plastics (Score:3, Informative)
I've seen these things dissolve in the slightest bit of an organic solvent (e.g. Dichloromethane or acetone)... and seen them melt with a souped up hairdryer (heatgun) at less than 200 degrees C. I wouldnt feel particularly safe with these materials shielding me from one of the harsher environs known to man (space).
Maby it's just my experience of seeing these substances take damage a lot, but i'd be real uneasy to trust my life to them over a bar of aluminum, which you can easily dip in water/organic solvents and heat to rediculous heats without so much as loosing it's bright metallic glint, let alone the all important structural integretiy.
If they're going to use plastics as a main part of the airframe, they're definately going to have to do some shielding from heat/radiation (U.V. light by itself can be quite destructive to certain plastics).
Re:Plastics (Score:2)
Mylar for example is extensively used as reflective material. You might recall the apollo lunar landers were wrapped in it, as shielding.
Spacesuits are extensively made of plastic. Nylon, teflon, kevlar and dacron are used.
As others have pointed out, temperature in space is not as severe as one might think (otherwise, the earth would be a giant oven or freezer -- the sun's heat has to go _somewhere_ after all, and it doesnt just vanish into another dimension after reaching t
Coming soon to a pair of scissors near you (Score:4, Funny)
How long will it be until they're packaging our scissors, walkmans, and USB hubs in this stuff? You thought those packages are hard to open NOW!
Here's the important part of the article (Score:4, Informative)
So this stuff is a fabric, so the implausible tensile strength numbers are probably for the individual fibers, not for a solid piece of the material. (The photo has him holding a "brick" of the material though.) Spider silk is as strong as high strength steel, and is very tough, but no one is suggesting building spaceships out of it. 2.6 times less dense than aluminum gives it about a density of 1, which is what polyethylenes typically are.
So they've managed to build a tough fibrous material. That's good, and it might make for a good micrometorite shield, and possibly a radiation shield. But it's not going to be a replacement for steel, titanium, or aluminum.
Not Very Surprising (Score:2, Informative)
Somehow, this _is_ how I envisioned it (Score:2)
I knew I was right!!! (Score:2)
I love this story, old / new materials (Score:2)
Confused?
Get the mp3 podcast of the article here.
Or:
Get audio of article here
Or
Get MP3 of article here
The word podcast was complete redundant in that sentence. I mean, really.
If any word should be found #ditch shot execution style, it should be 'podcast'. Please, make it go away!
Back on topic: Compared to aluminum, polyethylene is 50% better at shielding solar flares and 15% better for cosmic rays.
You a
Not quite right I suspect... (Score:2)
But out in space you have to contend with COSMIC RAYS, which are a whole other kettle of fish. They're much more energetic. So much so that if your typical plastic stops a cosmic "ray" (they're usually particles), the plastic emits a spray of even less desireable radiation.
Re:Not a Podcast! (Score:3, Informative)
I am subscribed with the iPodder app. Again, how is this not a podcast?
Re:Not a Podcast! (Score:2)
Re:Not a Podcast! (Score:2)
Re:Not a Podcast! (Score:2)
Oh sure... (Score:2)
Oh sure...they all laughed at me for wearing garbage bags instead of clothes but now...NOW who's the one laughing! Mwhahahahahaha!
I beg your pardon. (Score:3, Funny)
Sorry to bring you up there, but my system weighs around 40kg now with the fluid cooling and it's anything but portable; even If I could work off with it, It'd rip the IEC out of the UPS after 4 feet.
With intent. (Score:3, Informative)
This would suggest the file is intended for listening by anyone, anywhere with a Mpeg 3 player thethered or not.
It seems that the term podcast in this case was applied solely by the submitter to Slashdot.
Re:With intent. (Score:2)
Re:With intent. (Score:2)
Re:With intent. (Score:2)
It seems to me that the term podcast has nothing to do with space ships made out of plastic. I'm glad all these mod points were put to such effective use.
Re:With intent. (Score:2)
MPEG 2 layer 3 = mp3
i dont know what that means, but i'd take a guess that the audio is the third layer of an mpg2 file.
Re:Artificial Magnetic Field (Score:2)
Re:Artificial Magnetic Field (Score:2)
Re:Artificial Magnetic Field (Score:2)
Re:Heat shielding? (Score:2)
I am pretty sure the ablative heat shield on the apollo command module was made of epoxy resin. Remember how nasty that stuff can get when it is really hot. It doesn't turn to powder like wood. It just sits around, partly liquid and absorbs more heat.
Re:Heat shielding? (Score:2)
Currently they are worried about the ship bursting into flames when exposed to direct sunlight and oxygen.
The man who is patenting this is working on making it more heat resistant.
Re:Heat shielding? (Score:2)
Re:Heat shielding? (Score:3, Informative)
Re:Plastisteel (Score:2)
Re:Upgrades - foil hat (Score:2)
And you all laughed at me then.
Look who's laughing now?!
MUHAHAHAHAHAAHH!!
http://mirrors.meepzorp.com/ebay/pet-foil-hat/ [meepzorp.com]
In the world of radiation... (Score:2, Informative)
Poly (and water) make the best neutron radiation sheilding because it has alot of hydrogen atoms (one proton nuclei) which when hit with a loose neutron, will cause the neutron to loose 1/2 it's energy (two equal mass objects remember). So after a few collisions with a few Hydrogen nuclei (protons), the Neutro
Re:How does it stand up to radiation (Score:2)
NASA should also consider highly rigid polymers like polycyclopentene - PCP has a good strenght and much higher melting point than PE. It is more expensive to make but I guess the price here is not the biggest factor.
Re:Save me some time and bandwidth. (Score:2)
Re:The Moon and conspiracies. (Score:2)