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The article at the link below could go into the Nuclear is Safe topic as well.
However, I think it fits in this topic reasonably well:
https://www.yahoo.com/news/russian-scie … 00265.html
This is the first time I've heard the concept of using fusion as a primer for a fission reaction.
The reverse has been in practice (of course) for many decades.
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For SpaceNut ... this item could go several places ... I'm tossing it into the mix here just to give it exposure ...
https://www.syfy.com/syfywire/amazon-pa … e-launcher
The article at the link above explains that this patent is on the winsome side, as is true of a number of patents Amazon secures, but it could be the starting point for a useful discussion in the forum.
While I am personally skeptical of this ** particular ** patent, I am intrigued by the idea of a whiplash launch method.
I am personally daunted at the prospect of trying to do the math on what I'm about to describe, so I hope someone in the forum would be willing to tackle it ...
Given a payload to launch of 100 kg, of which 50 kg is a "rounding rocket",
and given a line of sufficient strength to withstand the forces I'm about to describe,
and given that the line is laid out on the surface of the Earth (or other body for that matter),
and given that the line is to be wound up on a drum by a motor of sufficient strength,
what are the dimensions of the system to launch the payload into LEO,
and what are the forces that are at work as the payload moves through the atmosphere?
The vehicle itself is NOT the payload. The vehicle will return to Earth as a glider for re-use.
The "rounding rocket" is the same one (or very similar) to the one that is needed for a ballistic launcher, such as the one proposed by Dr. John Hunter:
https://www.universetoday.com/51532/hyd … it-wvideo/
According to Dr. John Hunter, a physicist at Lawrence Livermore National Laboratory and president of the company Quicklaunch, Inc., using a hydrogen-powered cannon may be the ticket for cheap access to space. That’s right, a “space gun” platform for inserting satellites, fuel, and other supplies into space genuinely could be the next big thing in space technology.
I'm guessing the line would have to be a few hundred kilometers long but that estimate could be high, depending upon the effectiveness of the wings in providing vertical momentum while the vehicle is in the atmosphere.
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aka catapult launch, electric rail gun launcher ect.. force and mass equation for momentum to suborbital or to obit.
Its still just trying to beat the mass of dead weight once the engines and fuel have performed the launch of the payload.
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The article at the link below could go into the Nuclear is Safe topic as well.
However, I think it fits in this topic reasonably well:
https://www.yahoo.com/news/russian-scie … 00265.html
This is the first time I've heard the concept of using fusion as a primer for a fission reaction.
The reverse has been in practice (of course) for many decades.
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The hybrid reactor (as a concept) started receiving interest in the 1970s, in response to the energy crisis. The biggest advantage over a fast breeder reactor is much shorter doubling time. A sodium fast breeder reactor might need 30 years to produce enough excess plutonium to fuel another breeder reactor of the same power. If you need to build reactors quickly, that introduces a bottleneck. It also requires the use of sodium in its cooling circuit, as water would soften the neutron spectrum and ruin breeding ratio. With a hybrid reactor, a single unit could provide enough excess fissile material to fuel 2-3 light water reactors of the same power. If each of those reactors is a reduced moderation light water reactor, with high conversion ratio; you might only need a single 1GWe hybrid to support 10 or more LWRs of the same power.
The hybrid can also start with depleted uranium and build up fissile material starting from zero. The neutron spectrum is hard enough to fast fission 238U or 232Th. In principal, you could fast fission anything heavier than lead. So you can feed this reactor any collection of nasty actinide waste products you want rid of and it will break them down into short lived fission products yielding plenty of energy at the same time.
The big problem in the 70s was lack of technological readiness of the fusion driver. This wouldn't be such a problem today. We are much closer to break-even now. And the fusion part doesn't need to produce any net energy, given that each neutron produced by fusion would result in several fissions, each yielding 200MeV.
So the concept is a very good one if you want to build a closed fuel cycle without resorting to fast breeder reactors. In principle, it could be cheaper in the long run.
Last edited by Calliban (2020-02-17 16:04:17)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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For Calliban re #54
Thank you for your helpful reply! I'm encouraged by your closing paragraph.
It seems (to me at least) that a technology that could burn waste from earlier reactors would (or should) be welcome.
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For SpaceNut re #53
Thank you for your so OFTEN helpful comments designed to keep a topic moving.
For those who might discover this discussion as new visitors to the forum, the alternatives SpaceNut listed are distinctly different from the Amazon Whiplash patent, and certainly different from my proposal.
However, because SpaceNut has listed them for us to think about, I'll try to explain some of the differences as I understand them, and look forward to additional clarification by others with more knowledge or perhaps even experience.
aka catapult launch, electric rail gun launcher ect.. force and mass equation for momentum to suborbital or to obit.
All of the launch systems in the class given by SpaceNut impart ALL momentum in a single burst of applied energy.
The John Hunter ballistic launch design, featuring Hydrogen as the elastic fluid for propulsion, is an excellent addition to the list SpaceNut provided.
The Whiplash patent appears to employ a very long line manipulated by drones to achieve a launch velocity for the payload at the tip. The process of building up the energy needed for the launch is long, not short as is true for a catapult launch.
The system I have imagined would draw the payload toward the wind up reel gently, and at no time would G force exceed some low value. The system would look a LOT like a glider launcher on a glider field. There are several varieties of glider launch systems, but the one most applicable to this proposal is the "winch tow".
How to launch a glider - Winch tow
YouTube · 108,000+ views · 6/27/2012 · by DaveHax
The YouTube video at the location given above is helpful in understanding the concept. As can be seen, the launch is gentle and steady, and it takes place of an extended period of time, unlike any of the many rapid launch systems which exist or have been imagined.
I remain hopeful someone will find this concept worth developing as a math exercise.
The problem I have posed contains variables which must be chosen. I provided a payload of 50 kg to reach orbit, and a 50 kg rounding rocket, for a total mass tossed of 100 kg. However, the vehicle which carries the payload will have mass, just as the glider shown in the YouTube video has mass which eventually returns to Earth.
Edit#1: I found a discussion of a winch launch concept for ** something ** but I'm not sure what:
https://forum.nasaspaceflight.com/index … c=24756.20
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Last edited by tahanson43206 (2020-02-17 16:21:23)
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We have talked about the other means to cheat the first stage mass and velocity to get payloads to orbit in the past with high altitude balloons, to oxygen inlets for scram engines and for super cooling for use to make the lift capable. The small payload solid fueled rockets do a good job for price and reuse of old military engines of solid fuels.
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For SpaceNut re #57
The idea here is a Winch Tow system for launch from the surface of Earth or other bodies.
It is distinctly different from balloon launch, scram jet engines and other systems that depend upon rocket exhaust to perform first stage acceleration.
Potentially a Winch Tow system could operate without generating any greenhouse gases at all.
Hopefully someone in the forum community will find the concept interesting enough to take the time to perform the math to reveal what would be involved in realizing the concept.
As an addendum .... While the YouTube video shown in an earlier post showed that the Tow Winch was a fixed location machine, the winch mechanism for a satellite launch could be (and likely would be) considerably different because of the length of the cable. An alternative is to pull the cable with an electric train of sufficient strength to overcome the resistance of the atmosphere against the wings and underside of the lifting body.
As shown in the YouTube video, the glider with payload would be pulled toward a pulley mounted on a sufficiently strong axle, and the cable would be pulled away from the direction of acceleration of the glider.
Edit#1: Use of a Tow Winch concept is not out of the question for assisting with takeoff of airplanes under certain circumstances.
Launch of gliders is an established and commercially successful practice.
However, catapults are the preferred (and long practiced) method of accelerating aircraft from a short airfield such as an aircraft carrier. In addition, small solid motor rockets have been used for a similar purpose in the past.
A much larger tow winch system could be installed in a permanently short airfield such as on an island, if the economics of air travel were such that the expense could be justified.
I can imagine a special case in which such a system would be advantageous for Mars ... Because of the thin atmosphere, an airplane there must have a significant velocity before the wing can generate enough lift to support the mass of the aircraft and payload including fuel. By accelerating the aircraft with a tow winch system, the fuel on board the Mars vehicle can be saved for travel and for landing at the destination.
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Last edited by tahanson43206 (2020-02-18 09:31:02)
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sounds simular to the payload lander for phobos of which earth thick atmospher creates a hugh drag on the cable
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For SpaceNut re Tow Winch idea ... My apology for wasting anyone's time on this ... it didn't take long with a pad and pencil to discover that the glider tow winch can scale only so far, and (from a practical point of view) nowhere near what is needed for a satellite launch
The cable would have to be moving on the order of 17,000 miles per hour (or a bit less because the payload with have its own orbit smoothing rocket).
A tow winch system might work reasonably well on smaller bodies. It would have the distinct advantage of mechanical simplicity.
For SpaceNut re #59 ... that's an interesting observation that is new to me ... do you have a reference I can study?
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Last edited by tahanson43206 (2020-02-17 19:59:30)
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We see the same thing with the space elevators from earth to orbital places.
We also do not have the materials strenght needed or the ability to grow carbon nano tubes long enough to do so.
we talked about the tether for the moon of mars phobos:
http://newmars.com/forums/viewtopic.php?id=9239
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This quote is from an industry newsletter ... the research may have implications for Mars applications:
Molecular glass — A revolutionary new material enabling future OLED displays and lighting
Molecular glass, or glassy small molecule organic light-emitting diode materials, is a new class of organic semiconductor materials poised to overcome several performance and manufacturing hurdles currently limiting adoption of OLED technology.
Here is a Google result for OLED:
OLED stands for "organic light-emitting diode" and its cutting edge technology results from many innovations in display monitors, lighting, and more. As the name suggests, OLED technology is the next-generation advance of regular LEDs and LCDs, or liquid crystal displays.Aug 14, 2019
Overview of OLED Technology - ThoughtCo
What I'm thinking about here is the (potential) opportunity to line the walls of underground living and working quarters on Mars, with a complete surrounding able to replicate the visual experience of being anywhere spherical images can be captured. Google Earth has a feature that allows for spherical images captured by special cameras to be "viewed" by a user. In the case of the Google Earth display (as I have experienced it) the user operates controls to move the view around the sphere so that the user is able to sequentially view the entire surrounding given the patience to direct the display and wait for data flows.
In the Mars experience i am thinking about, the surrounding visual field would be static, except for such changes as moving clouds or waving grass.
Implementation of this concept would benefit from very inexpensive display technology.
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Last edited by tahanson43206 (2020-02-18 09:54:44)
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For SpaceNut ... the story at the link below could go into a "battery storage" topic if you have one. I looked for "battery storage" and skimmed through the list for a while before giving up.
The story reports on significant investment by major players in the energy field. I'm glad to see signs of life in this sector.
https://www.bizjournals.com/charlotte/n … es-as.html
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Batteries topics are by material and design type for the technology.
Had to google for more articles as it wanted pay for access...
https://finance.yahoo.com/m/483dac43-0d … ?.tsrc=rss
https://news.duke-energy.com/releases/d … est-in-n-c
2016 article for the use of hybrid ultracapacitor-battery energy storage system (HESS) in which the battery locations are distributed accross the grid so as to keep fluctuation in supply from occurring as loads come on and off.
If that was not enough Duke as been experimenting with getting the Lithium out of the battery to make a safer battery.
Aurora 2.0 is an aqueous zinc battery, built on 10 years of testing as a safe, scalable alternative to lithium-ion. Eos deploys its aqueous zinc battery system at projects in North Carolina and California
https://www.power-eng.com/2019/06/19/eo … ects/#gref
This might need its own topic area for further discusion.
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For SpaceNut re Tow Winch idea ... My apology for wasting anyone's time on this ... it didn't take long with a pad and pencil to discover that the glider tow winch can scale only so far, and (from a practical point of view) nowhere near what is needed for a satellite launch
The cable would have to be moving on the order of 17,000 miles per hour (or a bit less because the payload with have its own orbit smoothing rocket).
A tow winch system might work reasonably well on smaller bodies. It would have the distinct advantage of mechanical simplicity.
For SpaceNut re #59 ... that's an interesting observation that is new to me ... do you have a reference I can study?
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Tahanson, are the talking about towing a rocket behind an aeroplane (like a glider) and then launching it from the stratosphere? If so, I think your idea is solid. I don't think you could take a towed vehicle up to supersonic speeds. But rockets launched from the ground have low propulsive efficiency and burn a lot of fuel getting that initial few hundred metres per second of velocity and climbing up to 40,000 feet. And by launching from 40,000 feet, the rocket has a lot less air resistance to contend with. An air launched rocket like this may very well be able to reach orbit on a single stage with tolerably good payload fraction. If you could tow it behind a commonly available aircraft, like a 747, then it could be done relatively cheaply. A practical idea at first glance.
Last edited by Calliban (2020-02-22 15:15:16)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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That carrier plane tech is what was used for Spaceship One and with SS2 for sub orbital flights mostly to near space. The white Knight is the carrier plane for rocket launch so there are limits to the mass of the rocket that the plane can lift before firing its engines.
The pegasus rocket is just that sort of flight rocket in that its lofted to altituded and then allowed to drop away to fire its rocket engines.
So no cable attached to the rocket as its on the ground and must be brought upward with the plane which means its piggyback style.
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This is for Calliban re #66
For SpaceNut ... thanks for the reminder of carrier launch technology. As you point out, system designers have successfully bet big on this concept. I saw a report that the huge double Boeing 747 aircraft took its first flight recently. It may yet get a chance to put a launch vehicle into motion. If so, it has the potential to launch the largest such vehicle ever launched from flight.
However, to clarify for forum readers who might be trying to follow the discussion within an unbounded topic, Calliban and I are talking about "TOWED" launch.
To the best of my knowledge, a "towed" launch has never been attempted for a rocket vehicle. Towing of gliders has been going on successfully for many decades.
For Calliban ... Actually, my thinking to this point had been focused upon "tow winch" technology, which has the distinct advantage of extreme simplicity and only a few moving parts. That line of thinking was stimulated by the Amazon patents for a "whip" system to launch small satellites. I came to the conclusion that the "tow winch" idea is (most likely) not scalable.
However, to follow up, I dropped the question into Google, and right at the top of the list was NASA's research and development of EXACTLY what you have proposed! You seem to be on a roll these days << grin >>.
https://en.wikipedia.org/wiki/Towed_gli … nch_system
The article above seems to have started around 2015. It includes a 2018 reference, and the article was most recently updated December 30, 2019.
NASA plans to test the feasibility of releasing a small unpowered rocket from the one-third scale glider, followed by mounting a small rocket motor on the glider to test the feasibility of a rocket-assisted glider design. Further plans involve the construction of a full-scale platform. The project has obtained funding for NASA's 2015 financial year through the Game Changing Development program following the first successful test flight of the one-third scale glider.[5][10]
I am glad to see (modest) taxpayer funds used to explore this idea.
A modest success along the lines NASA was considering in 2015 could open minds to fund larger scale experiments.
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Last edited by tahanson43206 (2020-02-22 19:52:35)
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The article at the link below reports on MIT research to use AI to find anti-bacterial molecules.
While this research shows a path forward on Earth, it seems likely to become part of the medical technology to be established and maintained on Mars.
The risks to a small isolated population of a new biological threat arriving on a passenger ship from Earth are significant, so I expect that population will create and sustain a medical capability equal to the best on Earth.
What I was looking for but did not see was an indication the AI discovery technique could be used to find and kill virus. That would appear to be a direction worth looking, but I suppose this is a case of first things first.
https://www.engadget.com/2020/02/22/ai- … ntibiotic/
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"I expect that population will create and sustain a medical capability equal to the best on Earth"
I am not sure how feasible that would be. Certainly while the population of Mars remains in the 10s or 100s of thousands it will be extremely difficult I would say to develop the full range of human medical expertise, medicines production, pharma R&D, treatment processes, and state of the art machines (that all need monitoring and maintenance). Health will certainly be a priority and you are probably right to suggest there will be a focus on human to human infectious diseases.
The article at the link below reports on MIT research to use AI to find anti-bacterial molecules.
While this research shows a path forward on Earth, it seems likely to become part of the medical technology to be established and maintained on Mars.
The risks to a small isolated population of a new biological threat arriving on a passenger ship from Earth are significant, so I expect that population will create and sustain a medical capability equal to the best on Earth.
What I was looking for but did not see was an indication the AI discovery technique could be used to find and kill virus. That would appear to be a direction worth looking, but I suppose this is a case of first things first.
https://www.engadget.com/2020/02/22/ai- … ntibiotic/
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Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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For Calliban continuing #68 which itself was a reply to #66
In a post in the Unconventional LEO you mentioned the problem of moving humans to orbit with (relatively) low G forces. A towed rocket would appear to be a cost effective solution. A towed rocket vehicle would NOT have to be mated (very carefully) to a launch aircraft. Accordingly, a wide range of vendors could participate in a commercial launch activity. Some vendors could specialize in providing tow, and some could specialize in providing launch.
All vehicles could depart safely from commercial airports of sufficient size. Noise levels produced by equipment could be (and likely would be) kept to norms established for aircraft in densely populated regions.
There is a LOT to like about this idea, so I'm hoping someone in the forum will study the NASA proposal reported in #68 to see if it could be scaled up.
The entire operation proposed here is SO much safer than using rockets for launch from the surface of the Earth.
Elon Musk may be able to put his vision into practice, but everything will have to go perfectly right ** every ** launch (and landing).
An aircraft based launch system would appear (as I look at it) to have MUCH greater safety margin.
Even failure of the rocket stage to ignite after tow need not be a show stopper, if the launch site is chosen so that the vehicle can glide to a safe landing.
The business model to be built around the towed launch idea would seem likely to appeal to some investors, not to mention passengers.
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Last edited by tahanson43206 (2020-02-25 08:04:16)
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For SpaceNut ... the article at the link below describes ongoing development of thermal storage for energy.
Among other items that might be of interest, the author gives an example of a 1:10 advantage of thermal storage over pumped hydraulic storage, using water.
http://theconversation.com/how-heat-can … rgy-130549
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Last edited by tahanson43206 (2020-02-25 12:42:57)
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Just got back to look at this link and I was already on the same wavelegnth to use a heatpump design to aid in cooling a venus rover.
Heatpumps have been around for a while but its the cost and electrical cost that takes people aback to thinking that they are energy efficient. The heat produced in winter if we power from solar energy would be a net zero after the solar array pay back and when compared to throwing away your money on oil or electrical from the grid its a bargain to buy one when you can afford to do so.
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The article at the link below provides some encouraging updates for development of fusion power.
In particular, possibly of interest to Calliban, there is a report of an impact design using lasers, that would (apparently) guide hydrogen nuclei toward Boron atoms to achieve fusion as a (potentially) much more efficient process than the "traditional" heating of plasma to try to bang atoms together.
https://www.yahoo.com/finance/news/holy … 00475.html
The author points out differences between fission and fusion nuclear power, and updates the various development efforts going on around the world.
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Last edited by tahanson43206 (2020-02-27 20:04:07)
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Yes radiation after fusing is near none but at an atom one at a time will not produce the energy levels required to even sustain the magnetic fields needed to contain the force of the fusion of the atoms.
That field not only circles the chamber in one direction but also rotated cross ways to the other...
I posted an image of the field in the megasphere topics...
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