However, I wonder why scientist types only seem to research on blindness caused by degeneration or other failing parts. What about those of us who have damaged optic nerves?
There's been research with directly stimulating either the visual cortex or optic nerves, but it hasn't been as successful yet. Hopefully more progress will be made over time. Some links:
No, the parent was right, whether you get to 8km/s by a railgun or a rocket, you still have to be going 8km/s to orbit the earth, it's basic orbital mechanics.
But how do things change if you're able to somehow apply a non-trivial amount of constant acceleration, via something like a souped-up ion engine?
"Long term plans call for development of a heavy lift product and even a super-heavy, if there is customer demand. We expect that each size increase would result in a meaningful decrease in cost per pound to orbit. For example, dollar cost per pound to orbit dropped from $4,000 to $1,300 between Falcon 1 and Falcon 5. Ultimately, I believe $500 per pound or less is very achievable."
It should be noted that Elon Musk and Burt Rutan are both part of t/Space, a market-oriented company competing for the NASA contract to build the Crew Exploration Vehicle (the successor to the Space Shuttle).
Keep in mind that Musk's SpaceX is very much a rocket company, while Burt Rutan is very much an aeronautical guy. Even with SpaceShipOne, Rutan didn't design his own rocket, but bought one from SpaceDev. It'd be interesting to see what would result if SpaceX supplied a rocket, and Rutan designed some sort of reentry vehicle or carrier for air-launch.
It's relevant to note that SpaceX has already announced that they'll be competing for the Bigelow-funded America's Space Prize, for orbital human flight.
With most of the other space entrepreneurs focused on suborbital flight, Musk is closest to the holy grail of manned commercial spaceflight: orbit. Although Falcon I, with its single Merlin engine, will be able to launch only small satellites, five Merlins will be mated to the first stage of the far more powerful Falcon V rocket, perhaps as early as this year. Falcon V, Musk told Wired News, will be able to carry at least five people into low Earth orbit.
Five to orbit is a significant number; it's the number required to win the next big space prize. America's Space Prize is a $50 million purse established last year by Las Vegas hotelier and, yes, space entrepreneur, Robert Bigelow. Bigelow will award the money to the first U.S. company to build, without government funding, a spaceship that can send five people into orbit twice within 60 days. Bigelow has more than an academic interest in commercial spaceflight; through his Bigelow Aerospace, he's expanding his real estate empire off-planet with the first commercial space stations. While he can launch his stations on existing unmanned commercial rockets, he needs an orbital passenger vehicle to succeed in his venture.
Musk told Wired News that he intends to win America's Space Prize, and that he can do it by the Jan. 10, 2010, deadline (that's when Bigelow wants to open his commercial space station for business). The space prize is right in line with Musk's business plan. "We hope to be the company that takes people back and forth from Earth to either the International Space Station or to Bigelow's space station, or to applications we don't know about today," said Musk. Ultimately, though, his ambitions extend beyond even orbit. "I think it's very important that we become a spacefaring civilization, and that we eventually become multiplanetary."
The objective of this work is to recognize all the frontal faces of a character in the closed world of a movie or situation comedy, given a small number of query faces. This is challenging because faces in a feature-length film are relatively uncontrolled with a wide variability of scale, pose, illumination, and expressions, and also may be partially occluded. We develop a recognition method based on a cascade of processing steps that normalize for the effects of the changing imaging environment. In particular there are three areas of novelty: (i) we suppress the background surrounding the face, enabling the maximum area of the face to be retained for recognition rather than a subset; (ii) we include a pose refinement step to optimize the registration between the test image and face exemplar; and (iii) we use robust distance to a sub-space to allow for partial occlusion and expression change. The method is applied and evaluated on several feature length films. It is demonstrated that high recall rates (over 92%) can be achieved whilst maintaining good precision (over 93%).
There's a bunch of interesting papers out there on content-based image analysis and retrieval. Below is a sampling from my bibtex file. Does anyone else have others they'd like to share?
Of course, reusing good ideas is a good idea, IMHO. Still, even though the sexiness of wings certainly looks nicer, I'm thinking that the capsule-based proposals by Boeing/Northrop-Grumman and t/Space will be more cost-effective and reliable. Spacecraft need wings about as much as an aircraft needs to float.
Now if we can get a Crew Return Vehicle turned back back on we have a chance of fully populating the ISS. It would be a nice bonus if such a vehicle was a striped down (toilet-less, stowable) CEV that could use the same launch system.
You mean something like the X-38 (which was coincidentally constructed by Scaled Composites, Burt Rutan's company)?
NASA will choose this vehicle scematic or opt for the yet-released Northrop Grumman design in 2008.
Another company competing for NASA's contract to build the CEV is t/Space, which includes a number of notable members of the commercial spaceflight community, such as Burt Rutan, Elon Musk, Gary Hudson, and others. Their approach is expectedly much more market-oriented than Lockheed or Northrop-Grumman's, with the goal of constructing a self-sustaining commercial space infrastructure (like we have for aviation).
For the curious, midterm and final reports from the various competitors to NASA on their space exploration designs are available here. T/Space's midterm report is a particularly insightful read, detailing their plan for how commercial ventures and NASA can best cooperate to foster our access to space.
However, from the wiki article: "Some news reports in mid-March 2005, stemming from an interview with New Scientist, have reported that t/Space intends to withdraw from the competition, citing a high paperwork burden; however, no announcement of a withdrawal has yet been made by t/Space."
Personally, I really hope they're still in the running.
Because there's inevitably comments about the mission's name (which is the same as that of a Hollywood movie) whenever this is on slashdot, I figured I'd try to nip it in the bud. From this article:
"The scientists came up with the Deep Impact name independently of the movie studio, around the same time, neither knowing the other was choosing it, even though some members of NASA's Deep Impact team were consultants on the picture."
For those seeking more info, here's the Wikipedia article (on the mission, not the movie).
The PDF document by Edwards discusses this a little:
One issue brought up is the possibility of discharging the ionosphere. Our calculations based on the size and conductivity of the ribbon and the electrical properties exhibited in our upper atmosphere illustrate that a small area (square meters) around the ribbon could become discharged in the worst conditions. The magnitude of this discharging makes us believe with high confidence that no adverse local or global phenomenon will occur. It also shows that it is unlikely, without considerable effort, that any kind of usable power may be generated by this same method.
After submitting the article a few days ago, it's come to my attention that this isn't going to be the first nanotube factory; I didn't explicitly say anything of the sort in the submission, but wanted to clear any possible assumptions. From an industry report:
Among the small wonders produced by nanotechnology are carbon nanotubes, an advanced material as strong as diamond. These amazing carbon cylinders possess 100 times the tensile strength of steel and are 10,000 times finer than human hair. They are believed to conduct heat better than any other material, and they can also conduct electricity or function as semiconductors.
"Nanotubes are astonishingly promising, and I'm a realist, not an optimist," says Rod Ruoff, a mechanical engineering professor at Northwestern University. "It's a question of making the technology cheap enough." In 2001, only 3 kilograms of the highest quality carbon nanotubes--the single-walled variety--were produced worldwide, each gram worth $300, or 30 times as expensive as gold.
Now, full-scale production of carbon nanotubes is underway at the world's first ever large-scale nanotube factory, built outside Tokyo by the Carbon Nanotech Research Institute, a subsidiary of Japan's Mitsui & Co. The new facility is expected to churn out 10 tons of carbon nanotubes--albeit the lesser quality multi-walled type--a month, and CNRI anticipates the price will be a much more reasonable $80 a kilogram.
These multi-walled carbon nanotubes may not possess all the impressive properties of their single-walled brethren, but mixed with plastics, they make ultrastrong composites or microscale precision parts. Such carbon nanotube-filled plastics are already being used by automakers in fuel lines because they are conductive and can thus be grounded to release static electricity, which can ignite flammable gasoline.
It seems to me that were going to spend entirely to much money on something that is old obsolete. Why not replace it with something new and better?
IMHO, we should. A copy from an old post of mine:
Hubble Origins Probe: replace instead of repair?
Astronomy Magazine reports that an international team of astronomers has proposed an alternative to sending a robotic or human repair mission to the ailing Hubble Space Telescope. Their proposal is to build a new Hubble Origins Probe, reusing the Hubble design but using lighter and more cost-effective technologies. The probe would include instruments currently waiting to be installed on Hubble, as well as a Japanese-built imager which 'will allow scientists to map the heavens more than 20 times faster than even a refurbished Hubble Space Telescope could.' It would take an estimated 65 months and under $1 billion to build and launch, less than the estimated cost of a service mission.
So your plan is to replace something which is in many ways the essence of pork-barrel politics (i.e. the source of tens of thousands of constituent jobs and local funding), and replace it with competitive enterprise (essentially the opposite of pork-barrel). Sure, that sounds great, but it's politically dead in the water.
Don't get me wrong, I'm a big fan of things like the Centennial Challenges. However, there's a reason that Congress put a cap on how much NASA could spend on that program.
Subhayu Basu, Yoram Gerchman, Cynthia H. Collins, Frances H. Arnold and Ron Weiss
Nature 434, 1130-1134 (28 April 2005)
Pattern formation is a hallmark of coordinated cell behaviour in both single and multicellular organisms1, 2, 3. It typically involves cellcell communication and intracellular signal processing. Here we show a synthetic multicellular system in which genetically engineered 'receiver' cells are programmed to form ring-like patterns of differentiation based on chemical gradients of an acyl-homoserine lactone (AHL) signal that is synthesized by 'sender' cells. In receiver cells, 'band-detect' gene networks respond to user-defined ranges of AHL concentrations. By fusing different fluorescent proteins as outputs of network variants, an initially undifferentiated 'lawn' of receivers is engineered to form a bullseye pattern around a sender colony. Other patterns, such as ellipses and clovers, are achieved by placing senders in different configurations. Experimental and theoretical analyses reveal which kinetic parameters most significantly affect ring development over time. Construction and study of such synthetic multicellular systems can improve our quantitative understanding of naturally occurring developmental processes and may foster applications in tissue engineering, biomaterial fabrication and biosensing.
This conference abstract is also pretty darned cool:
Hsu, Allen (Princeton Univ.), Vijayan, Vikram (Princeton Univ.), Fomundam, Lawrence (Univ. of Maryland, Baltimore County), Gerchman, Yoram (Princeton Univ.), Basu, Subhayu (Princeton Univ.), Karig, David (Princeton Univ.), Hooshangi, Sara (Princeton Univ.), Weiss, Ron (Princeton Univ.)
2005 American Control Conference
Control system theory provides convenient tools and concepts for describing and analyzing complex cell functions. In this paper we demonstrate the use of control theory to forward-engineer a complex synthetic gene network constructed from several modular components. Specifically, we present the design and simulation of a synthetic multi-cellular maze-solving system. Here, bacterial cells are programmed to use artificial cell-to-cell communication and regulatory feedback in order to illuminate the correct path in a user-defined maze of cells arranged on a surface. Simulations were used to analyze the system's spatiotemporal dynamics and sensitivity to various kinetic parameters. Experiments with Escherichia coli were carried out to characterize the diffusion properties of artificial cell-to-cell communication based on bacterial quorum sensing systems. The rational design process and simulation tools employed in this study provide an example for future engineering of complex synthetic gene networks comprising multiple control system motifs.
The single largest contributer to launch cost is vehicle R&D.
Are you certain about that? I was under the impression that the largest cost contributor, at least for manned systems, it's the cost of paying the "standing army" required for maintaining and prepping the craft while it's on the ground. I recall hearing a figure of around 20,000 people needed to maintain the shuttle.
Having a universe with a human population spreading effectively in it summons an eerie image on a spherically expanding brain-tumor to my mind...
I find it curious that you'd think of it as a brain tumor, instead of just a rapidly expanding brain. Personally, I can think of few goals more noble than expanding intelligence and conscious thought throughout the universe.
To clarify my position, I'm actually very much in favor of Project Prometheus, but I'm not so sure that JIMO is the best initial application for this. I'd prefer to see a prototype nuclear reactor on a much smaller and less complex test mission first, before sticking it on something massively complicated like JIMO.
Space.com had an article on possible alternatives a little while back. A snippet:
NASA is reviewing a list of fission-powered missions that could pre-empt the Jupiter Icy Moons Orbiter (JIMO) effort now being eyed for space travel no sooner than 2015.
A special study team has identified six potential candidate missions that could be done sooner, have shorter mission durations, and would be far less difficult to implement... The six ideas are:
* Technology Demonstration Mission to test fission power system in deep space with no specific science goal or destination.
* Lunar Geophysical Orbiter that in extended mission mode could serve as a telecom asset for future lunar missions.
* Next Generation Mars Telecommunications Station.
* Near Earth Object (NEO) Asteroid Mission that would involve stopovers at multiple objects, perhaps landing hardware on a NEO to assess the ability to modify the trajectory of a celestial body.
* Venus Orbiter, more like a Magellan II spacecraft that would carry out low altitude runs over the cloudy planet with state-of-the-art radar.
* Astrophysics Mission that would use high power levels from a fission power source, likely sending collected science information at very high data rates.
Slashdot Mirror
However, I wonder why scientist types only seem to research on blindness caused by degeneration or other failing parts. What about those of us who have damaged optic nerves?
There's been research with directly stimulating either the visual cortex or optic nerves, but it hasn't been as successful yet. Hopefully more progress will be made over time. Some links:
http://cortivis.umh.es/overview.htm
http://www.md.ucl.ac.be/gren/mivipresult.html
No, the parent was right, whether you get to 8km/s by a railgun or a rocket, you still have to be going 8km/s to orbit the earth, it's basic orbital mechanics.
But how do things change if you're able to somehow apply a non-trivial amount of constant acceleration, via something like a souped-up ion engine?
Anyone else wondering if it's named that because of the Millenium Falcon?
According to this press release, the name of the Falcon I is indeed a tribute to Han Solo's spacecraft.
That said, is it feasible that we will see it reduced by a factor of 1000?
From an interview with Elon Musk:
"Long term plans call for development of a heavy lift product and even a super-heavy, if there is customer demand. We expect that each size increase would result in a meaningful decrease in cost per pound to orbit. For example, dollar cost per pound to orbit dropped from $4,000 to $1,300 between Falcon 1 and Falcon 5. Ultimately, I believe $500 per pound or less is very achievable."
(Not quite 1000x less, but it's close.)
Should Burt Rutan be consulted?
It should be noted that Elon Musk and Burt Rutan are both part of t/Space, a market-oriented company competing for the NASA contract to build the Crew Exploration Vehicle (the successor to the Space Shuttle).
Keep in mind that Musk's SpaceX is very much a rocket company, while Burt Rutan is very much an aeronautical guy. Even with SpaceShipOne, Rutan didn't design his own rocket, but bought one from SpaceDev. It'd be interesting to see what would result if SpaceX supplied a rocket, and Rutan designed some sort of reentry vehicle or carrier for air-launch.
It's relevant to note that SpaceX has already announced that they'll be competing for the Bigelow-funded America's Space Prize, for orbital human flight.
8 ,00.html
http://wired-vig.wired.com/news/space/0,2697,6630
With most of the other space entrepreneurs focused on suborbital flight, Musk is closest to the holy grail of manned commercial spaceflight: orbit. Although Falcon I, with its single Merlin engine, will be able to launch only small satellites, five Merlins will be mated to the first stage of the far more powerful Falcon V rocket, perhaps as early as this year. Falcon V, Musk told Wired News, will be able to carry at least five people into low Earth orbit.
Five to orbit is a significant number; it's the number required to win the next big space prize. America's Space Prize is a $50 million purse established last year by Las Vegas hotelier and, yes, space entrepreneur, Robert Bigelow. Bigelow will award the money to the first U.S. company to build, without government funding, a spaceship that can send five people into orbit twice within 60 days. Bigelow has more than an academic interest in commercial spaceflight; through his Bigelow Aerospace, he's expanding his real estate empire off-planet with the first commercial space stations. While he can launch his stations on existing unmanned commercial rockets, he needs an orbital passenger vehicle to succeed in his venture.
Musk told Wired News that he intends to win America's Space Prize, and that he can do it by the Jan. 10, 2010, deadline (that's when Bigelow wants to open his commercial space station for business). The space prize is right in line with Musk's business plan. "We hope to be the company that takes people back and forth from Earth to either the International Space Station or to Bigelow's space station, or to applications we don't know about today," said Musk. Ultimately, though, his ambitions extend beyond even orbit. "I think it's very important that we become a spacefaring civilization, and that we eventually become multiplanetary."
I forgot one more, where specific faces were automatically retrieved from feature-length movies and Fawlty Towers:
Automatic Face Recognition for Film Character Retrieval in Feature-Length Films (Arandjelovic & Zisserman, 2005)
The objective of this work is to recognize all the frontal faces of a character in the closed world of a movie or situation comedy, given a small number of query faces. This is challenging because faces in a feature-length film are relatively uncontrolled with a wide variability of scale, pose, illumination, and expressions, and also may be partially occluded. We develop a recognition method based on a cascade of processing steps that normalize for the effects of the changing imaging environment. In particular there are three areas of novelty: (i) we suppress the background surrounding the face, enabling the maximum area of the face to be retained for recognition rather than a subset; (ii) we include a pose refinement step to optimize the registration between the test image and face exemplar; and (iii) we use robust distance to a sub-space to allow for partial occlusion and expression change. The method is applied and evaluated on several feature length films. It is demonstrated that high recall rates (over 92%) can be achieved whilst maintaining good precision (over 93%).
There's a bunch of interesting papers out there on content-based image analysis and retrieval. Below is a sampling from my bibtex file. Does anyone else have others they'd like to share?
* Finding Naked People (Fleck et al, 1996)
* Video google: A text retrieval approach to object matching in videos (Sivic & Zisserman, 2003): web page demo here
* Names and Faces in the News (Berg et al, 2004)
* FACERET: An Interactive Face Retrieval System Based on Self-Organizing Maps (Ruiz-del-Solar et al, 2002)
* Costume: A New Feature for Automatic Video Content Indexing (Jaffre 2005)
Good points.
* LockMart CEV proposal
* Big Gemini
* X-20A Dynasoar
* Russian Kliper
Of course, reusing good ideas is a good idea, IMHO. Still, even though the sexiness of wings certainly looks nicer, I'm thinking that the capsule-based proposals by Boeing/Northrop-Grumman and t/Space will be more cost-effective and reliable. Spacecraft need wings about as much as an aircraft needs to float.
But the new concepts lack something, i don't know...sexy.
You were expecting racing stripes and low-riding wheels, perhaps?
Now if we can get a Crew Return Vehicle turned back back on we have a chance of fully populating the ISS. It would be a nice bonus if such a vehicle was a striped down (toilet-less, stowable) CEV that could use the same launch system.
You mean something like the X-38 (which was coincidentally constructed by Scaled Composites, Burt Rutan's company)?
NASA will choose this vehicle scematic or opt for the yet-released Northrop Grumman design in 2008.
Another company competing for NASA's contract to build the CEV is t/Space, which includes a number of notable members of the commercial spaceflight community, such as Burt Rutan, Elon Musk, Gary Hudson, and others. Their approach is expectedly much more market-oriented than Lockheed or Northrop-Grumman's, with the goal of constructing a self-sustaining commercial space infrastructure (like we have for aviation).
For the curious, midterm and final reports from the various competitors to NASA on their space exploration designs are available here. T/Space's midterm report is a particularly insightful read, detailing their plan for how commercial ventures and NASA can best cooperate to foster our access to space.
However, from the wiki article: "Some news reports in mid-March 2005, stemming from an interview with New Scientist, have reported that t/Space intends to withdraw from the competition, citing a high paperwork burden; however, no announcement of a withdrawal has yet been made by t/Space."
Personally, I really hope they're still in the running.
Indeed. I've had my email on the slashdot front page once or twice, and almost no spam gets through the filter.
Because there's inevitably comments about the mission's name (which is the same as that of a Hollywood movie) whenever this is on slashdot, I figured I'd try to nip it in the bud. From this article:
"The scientists came up with the Deep Impact name independently of the movie studio, around the same time, neither knowing the other was choosing it, even though some members of NASA's Deep Impact team were consultants on the picture."
For those seeking more info, here's the Wikipedia article (on the mission, not the movie).
The PDF document by Edwards discusses this a little:
One issue brought up is the possibility of discharging the ionosphere. Our calculations based on the size and conductivity of the ribbon and the electrical properties exhibited in our upper atmosphere illustrate that a small area (square meters) around the ribbon could become discharged in the worst conditions. The magnitude of this discharging makes us believe with high confidence that no adverse local or global phenomenon will occur. It also shows that it is unlikely, without considerable effort, that any kind of usable power may be generated by this same method.
After submitting the article a few days ago, it's come to my attention that this isn't going to be the first nanotube factory; I didn't explicitly say anything of the sort in the submission, but wanted to clear any possible assumptions. From an industry report:
Among the small wonders produced by nanotechnology are carbon nanotubes, an advanced material as strong as diamond. These amazing carbon cylinders possess 100 times the tensile strength of steel and are 10,000 times finer than human hair. They are believed to conduct heat better than any other material, and they can also conduct electricity or function as semiconductors.
"Nanotubes are astonishingly promising, and I'm a realist, not an optimist," says Rod Ruoff, a mechanical engineering professor at Northwestern University. "It's a question of making the technology cheap enough." In 2001, only 3 kilograms of the highest quality carbon nanotubes--the single-walled variety--were produced worldwide, each gram worth $300, or 30 times as expensive as gold.
Now, full-scale production of carbon nanotubes is underway at the world's first ever large-scale nanotube factory, built outside Tokyo by the Carbon Nanotech Research Institute, a subsidiary of Japan's Mitsui & Co. The new facility is expected to churn out 10 tons of carbon nanotubes--albeit the lesser quality multi-walled type--a month, and CNRI anticipates the price will be a much more reasonable $80 a kilogram.
These multi-walled carbon nanotubes may not possess all the impressive properties of their single-walled brethren, but mixed with plastics, they make ultrastrong composites or microscale precision parts. Such carbon nanotube-filled plastics are already being used by automakers in fuel lines because they are conductive and can thus be grounded to release static electricity, which can ignite flammable gasoline.
Friggin' awesome?
I think the original poster meant that SOX is friggin' awesome for consultants in the same sense that the Y2K bug was friggin' awesome.
It seems to me that were going to spend entirely to much money on something that is old obsolete. Why not replace it with something new and better?
IMHO, we should. A copy from an old post of mine:
Hubble Origins Probe: replace instead of repair?
Astronomy Magazine reports that an international team of astronomers has proposed an alternative to sending a robotic or human repair mission to the ailing Hubble Space Telescope. Their proposal is to build a new Hubble Origins Probe, reusing the Hubble design but using lighter and more cost-effective technologies. The probe would include instruments currently waiting to be installed on Hubble, as well as a Japanese-built imager which 'will allow scientists to map the heavens more than 20 times faster than even a refurbished Hubble Space Telescope could.' It would take an estimated 65 months and under $1 billion to build and launch, less than the estimated cost of a service mission.
So your plan is to replace something which is in many ways the essence of pork-barrel politics (i.e. the source of tens of thousands of constituent jobs and local funding), and replace it with competitive enterprise (essentially the opposite of pork-barrel). Sure, that sounds great, but it's politically dead in the water.
Don't get me wrong, I'm a big fan of things like the Centennial Challenges. However, there's a reason that Congress put a cap on how much NASA could spend on that program.
::digs around for relevant info::
First off, here's the web page for Ron Weiss, the scientist mentioned in the article.
Here's (what I think is) the relevant publication on the topic:
A synthetic multicellular system for programmed pattern formation
Subhayu Basu, Yoram Gerchman, Cynthia H. Collins, Frances H. Arnold and Ron Weiss
Nature 434, 1130-1134 (28 April 2005)
Pattern formation is a hallmark of coordinated cell behaviour in both single and multicellular organisms1, 2, 3. It typically involves cellcell communication and intracellular signal processing. Here we show a synthetic multicellular system in which genetically engineered 'receiver' cells are programmed to form ring-like patterns of differentiation based on chemical gradients of an acyl-homoserine lactone (AHL) signal that is synthesized by 'sender' cells. In receiver cells, 'band-detect' gene networks respond to user-defined ranges of AHL concentrations. By fusing different fluorescent proteins as outputs of network variants, an initially undifferentiated 'lawn' of receivers is engineered to form a bullseye pattern around a sender colony. Other patterns, such as ellipses and clovers, are achieved by placing senders in different configurations. Experimental and theoretical analyses reveal which kinetic parameters most significantly affect ring development over time. Construction and study of such synthetic multicellular systems can improve our quantitative understanding of naturally occurring developmental processes and may foster applications in tissue engineering, biomaterial fabrication and biosensing.
This conference abstract is also pretty darned cool:
Dynamic Control in a Coordinated Multi-Cellular Maze Solving System
Hsu, Allen (Princeton Univ.), Vijayan, Vikram (Princeton Univ.), Fomundam, Lawrence (Univ. of Maryland, Baltimore County), Gerchman, Yoram (Princeton Univ.), Basu, Subhayu (Princeton Univ.), Karig, David (Princeton Univ.), Hooshangi, Sara (Princeton Univ.), Weiss, Ron (Princeton Univ.)
2005 American Control Conference
Control system theory provides convenient tools and concepts for describing and analyzing complex cell functions. In this paper we demonstrate the use of control theory to forward-engineer a complex synthetic gene network constructed from several modular components. Specifically, we present the design and simulation of a synthetic multi-cellular maze-solving system. Here, bacterial cells are programmed to use artificial cell-to-cell communication and regulatory feedback in order to illuminate the correct path in a user-defined maze of cells arranged on a surface. Simulations were used to analyze the system's spatiotemporal dynamics and sensitivity to various kinetic parameters. Experiments with Escherichia coli were carried out to characterize the diffusion properties of artificial cell-to-cell communication based on bacterial quorum sensing systems. The rational design process and simulation tools employed in this study provide an example for future engineering of complex synthetic gene networks comprising multiple control system motifs.
The single largest contributer to launch cost is vehicle R&D.
Are you certain about that? I was under the impression that the largest cost contributor, at least for manned systems, it's the cost of paying the "standing army" required for maintaining and prepping the craft while it's on the ground. I recall hearing a figure of around 20,000 people needed to maintain the shuttle.
Oops, that was supposed to be posted to the GP, not the P.
Having a universe with a human population spreading effectively in it summons an eerie image on a spherically expanding brain-tumor to my mind...
I find it curious that you'd think of it as a brain tumor, instead of just a rapidly expanding brain. Personally, I can think of few goals more noble than expanding intelligence and conscious thought throughout the universe.
Thanks for the link.
To clarify my position, I'm actually very much in favor of Project Prometheus, but I'm not so sure that JIMO is the best initial application for this. I'd prefer to see a prototype nuclear reactor on a much smaller and less complex test mission first, before sticking it on something massively complicated like JIMO.
Space.com had an article on possible alternatives a little while back. A snippet:
NASA is reviewing a list of fission-powered missions that could pre-empt the Jupiter Icy Moons Orbiter (JIMO) effort now being eyed for space travel no sooner than 2015.
A special study team has identified six potential candidate missions that could be done sooner, have shorter mission durations, and would be far less difficult to implement... The six ideas are:
* Technology Demonstration Mission to test fission power system in deep space with no specific science goal or destination.
* Lunar Geophysical Orbiter that in extended mission mode could serve as a telecom asset for future lunar missions.
* Next Generation Mars Telecommunications Station.
* Near Earth Object (NEO) Asteroid Mission that would involve stopovers at multiple objects, perhaps landing hardware on a NEO to assess the ability to modify the trajectory of a celestial body.
* Venus Orbiter, more like a Magellan II spacecraft that would carry out low altitude runs over the cloudy planet with state-of-the-art radar.
* Astrophysics Mission that would use high power levels from a fission power source, likely sending collected science information at very high data rates.