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New proposal could better protect space crews from radiation during long-term missions  (Source: www.luther.edu)
NASA believes active electrostatic radiation shielding is the best form of radiation protection during long-term missions

NASA is searching for a potential partner in the development of a proposal for radiation shielding during long-term space flights.

Radiation protection currently used, which is based on materials shielding, has several issues that need to be addressed and improved before it can be utilized in space. A major issue is that current materials shielding does not fully prevent long-term exposure to radiation. There is also a lack of data and studies associated with long-term tissues exposure to radiation with materials shielding in place, which further hinders any progress for this particular technology. In addition, cost is a problem that prohibits the use of current radiation protection for long periods of time. 

To address the above-mentioned problems, NASA is looking for candidates who would like to create a proposal along with NASA scientists and engineers. More specifically, NASA would like a potential partner that can develop a proposal that will utilize active electrostatic radiation shielding, which is believed to be the best radiation protection for long-term missions. This active electrostatic radiation shielding should make use of state-of-the-art evolutionary materials shielding technologies as well, according to NASA's specifications. 

Active electrostatic radiation shielding stops ions from hitting a spacecraft, which reduces unknown harmful effects due to long-term radiation exposure by 70 percent for galactic cosmic rays. As far as solar particle events go, the use of active electrostatic radiation shielding "practically eliminates" it. 

Those looking to work with NASA LaRC must have expertise in assessments of radiation exposure dose, experience with modeling and simulation, fabricated expandable structures for space-related needs, and have worked with electrons accelerators and charged ions. Those looking to work with the NASA Innovative Advanced Concepts (NIAC), where the NASA Research Announcement (NRA) "solicits" studies that research mission, system or architecture-related concepts, must be innovative and very early in development when it comes to the validation of active electrostatic radiation shielding. 

Partners will be chosen based on experience, past performance, technical capability, key personnel availability and demonstration of work on modeling and simulation, fabricated expandable structures for space-related needs, electrons accelerators and charged ions. If chosen, partners will be expected to create electrostatic active radiation shielding configurations, make simulation investigations, assess exposure for these configurations, fabricate expandable structures and prepare laboratory validation. 


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RE: If they partner with...
By FITCamaro on 3/22/2011 8:39:02 PM , Rating: 3
I don't see why they don't just line the hull of the ship with lead.


RE: If they partner with...
By randomly on 3/22/2011 9:40:52 PM , Rating: 5
Lead is a poor shielding material for cosmic rays and solar protons which are the major radiation threat in space. Lead is only effective for x-ray/gamma rays (photons). A thin lead shield in space is worse than no shield at all because cosmic rays are so high energy that a single collision with a lead atom produces a huge shower of secondary radiation.

It would take meters thick of lead to be effective against cosmic rays. Mass reduction is paramount for spacecraft, high mass shielding systems are just not practical.

Solar protons (high velocity hydrogen nuclei), and cosmic rays (various high velocity nuclei from hydrogen up to iron) are best shielded with the lightest weight atoms. Liquid Hydrogen being the best. Hydrogen rich plastics are another option and have more convenient physical properties but are not as effective at shielding.

Since nuclei are charge particles the other shielding options are magnetic fields and high voltage electrostatic fields, which is what NASA wants to pursue.

The whole problem is achieving effective shielding with a minimum of mass. Brute force doesn't cut it in space.


RE: If they partner with...
By amagriva on 3/23/2011 7:05:07 AM , Rating: 3
Pfff! Those rednecks still don't get the unleaded thing...


RE: If they partner with...
By AssBall on 3/23/2011 8:17:39 AM , Rating: 2
Why not just have two counter-rotating inhabitable rings with spaced electromagnets form the inhabitable section of your craft? Join them at the hub so you can move between them.

This gives you:
-an electromagnetic shield.
-some gravity.
-fights precession.

Power it all with a Nuclear source (voyager is doing pretty good with it's tiny 35 year old nuclear power plant).


RE: If they partner with...
By FITCamaro on 3/23/2011 9:45:15 AM , Rating: 2
Yeah if we're going to have long term space travel, eventually we're going to have to start looking at ways to have artificial gravity.


RE: If they partner with...
By MrBlastman on 3/23/2011 12:42:54 PM , Rating: 2
I don't think we can ever have fully effective artificial gravity until we can fully and completely understand the fourth fundamental force (gravitation). We still don't.

Moving structures such as spin-based artifical gravity and so on are nice, but, they only provide a consistent level from a set distance from the center--i.e. @ 50 meters it is 1 g, but at 10 meters it might be .05 g's of gravity, so you have wasted space--or, the requirement of the work centers (the place people spend most of their activity while awake) being situated in those 1g areas, while the rest and sleep areas being situated away from there. Electromagnetic solutions are also possible but even then, the strain on the human body would potentially not be equal at all times thus not fully alleviating atrophy.

It's a complicated tradeoff. It also presents many design decisions to not just stations but spacecraft themselves. I feel the greatest contribution towards solving this dilemma would be further understanding this fourth force itself. Not to mention once we do understand it, it will potentially open far more doors towards propulsion or... transport over great distances.


RE: If they partner with...
By MrBlastman on 3/23/2011 12:50:44 PM , Rating: 2
I like the concept of RTG (Radioisotop thermoelectric generator) power generation, which you specifically reference, the downside of which is the wattage that is generated. While these powerplants are sustainable for a long period of time, they just don't generate enough output for a spacecraft that is manned by humans to be considered as the primary source of power. Their net effeciencies are only @ about 3-7%.

But, you address a very real problem. How are they going to power this electrostatic shielding. As it requires high voltage (we don't know amperage), something beyond batteries and solar cells will be needed (as distance increases from the sun, solar output decreases). So really, the only thing we have currently is somehow fitting a small fission-reactor inside a spacecraft. They do this already in Submarines which, in reality, are the closest thing we have to a spacecraft here on earth. The downside is they are so big--not to mention propellers don't really cut it in space (even if the Moon really was made out of Cheese ;) ).

This is why we need Nasa. Nasa realizes these problems and albeit slowly, makes progress towards solving them which ultimately benefits all of us.


RE: If they partner with...
By FITCamaro on 3/23/2011 1:43:32 PM , Rating: 4
You mean NASAs main goal shouldn't be better relations with the Arab world?


RE: If they partner with...
By MrBlastman on 3/23/2011 2:06:33 PM , Rating: 2
They've already made first contact.

Unfortunately, the Arab in the sand said to the NASA Man, "I come in peace," whence the NASA Man sighed in relief, only to proclaim, "I think I see the origin of the Sun!... As the Arab in the sand exploded into a fireball,
taking the NASA Man with him.

He came in peace, he left in pieces.

Tax dollars well spent. Not. :-|


RE: If they partner with...
By randomly on 3/23/2011 6:26:55 PM , Rating: 2
The voltage needs to be extremely high, but the current will be very low. It should not take a great deal of power to run an electrostatic system.

Out to the orbit of Mars or even the asteroid belt Solar panels can achieve a considerably higher power to weight ratio than nuclear power (an order of magnitude better). Nuclear power becomes necessary at Jupiter and beyond, or if your craft suffers day/night cycles.

NASA wants to move to ASRG (Advanced Sterling Radioisotope Generator) anywhere the extreme reliability of RTGs is not needed. ASRG are around 25% efficient, produce more power, weigh less, and cost less. They also use only 1/4 as much Plutonium 238 which is currently in extremely short supply and is no longer in production anywhere in the world. NASA is already constrained in future missions due to the shortage of PU238.


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