Breakthrough In-Space Propulsion for Affordable Mars Missions

kbd512 · 2016-11-04 14:56:42

As suggested by the topic of this post, I want to gather feasible ideas for better in-space propulsions technologies.

Thus far, I have identified three specific propulsion technology developments that appear to enable rapid transfer of humans and cargo to Mars.

1. Dr. Shawyer - EMDrive or Q-Thruster

Q-thrusters are a novel use of microwave radiation to produce a propulsive force somewhat more efficiently than traditional reaction mass electrical thrusters. This technology will be flown in space in the very near future. If it works in space, it's a true breakthrough and becomes the first thruster to produce propulsive force without reaction mass or propellant. The minute thrust produced is still on par with current electric propulsion technologies and appears to be most suitable for cargo delivery.

.3 newtons per kilowatt of input power

Although all experimental evidence suggests Q-thrusters work as advertised, there have been some issues cooling the high power microwave emitters required. However, if it works in space someone will solution that problem.

2. Dr. Nassikas - Super-Conducting Lorentz Thruster or S-Thruster

Although reaction-less like the Q-thrusters, albeit using entirely different operating principles, this technology uses superconductors and Lorentz forces to produce propulsive force. This technology is even less well-understood than the Q-thruster technology. However, it produces substantially more thrust, using substantially less input electrical power. There are claims that no input electrical power is required, but this is patently false since a cryocooler is required to cool the thruster.

Like the Q-thruster, this technology has already passed a pendulum test (produces thrust in both directions and when the thruster is warmed it produces no thrust.

This technology is simple and inexpensive, compared to reaction mass thrusters or Q-thrusters, but requires deeply cryogenic temperatures for operation (-196C/-321F). Only a cryocooler can produce such low temperatures, thus it is not zero-input power as claimed.

Compared to the NSTAR ion engine used on NASA's Dawn spacecraft, the thruster is pretty impressive. Dawn devoted 425kg of Xenon propellant and each of the three ion engines weighed 8.9kg and produced 92mN of thrust. By way of comparison, the S-thruster prototype produces 21mN of force and weighs .12kg (which does not include the mass of the cryocooler or power supply for the cryocooler). 23 such engines could produce the same 276mN of thrust as Dawn's three NSTAR engines at a weight of 2.76kg. The Dawn spacecraft would be at least 425kg lighter with S-thrusters.

That level of performance was achieved with Version I, which simply had permanent magnets built into the base of the thruster. Version II, yet to be built, is capable of much higher field strengths because it uses electromagnets instead of permanent magnets.

Even using Version I, the thruster could easily achieve what dawn achieved without $510,000 worth of propellant. The Version I thruster has no moving parts and requires no electrical power, so overall system reliability is determined only by the reliability of the cryocooler and power subsystem that provides electrical power to the cryocooler. Version II uses an electromagnet, but still has no moving parts. In 2015, the first all solid state cryocooler achieved temperatures below 100K, so in the next two to four years it should be possible to have all solid state propulsion hardware.

3. Dr. Slough - Fusion Driven Rocket

The fusion driven rocket superheats a Deuterium-Tritium pellet to the point of fusing by trapping the pellet in an electromagnetic field of exponentially increasing field strength using a metallic liner made of aluminum or lithium. The electromagnets collapse the liner at 2km/s to 3km/s, which is what produces the powerful electromagnetic field. The radiation produced from fusion is mostly trapped by the lithium liner, which vaporizes, and produces thrust by being electromagnetically expelled from the ignition chamber. This process is repeated at a rate of 14 cycles per second and produces a 36MW jet of vaporized lithium propellant. The rocket nozzle is mounted on a pusher plate to absorb the force of the "push" on the rest of the spacecraft. This pulsed power application solely relies on solar arrays and capacitors to produce and store the electrical power required to collapse the lithium liner onto the D-T pellet that produces fusion and to power the electromagnetic rocket nozzle.

The electromagnetic field applied to the liner has to be uniform to prevent disintegration of the liner, but fusion using this method has been experimentally proven in a variety of lab experiments. This is the first practical propulsion application. It does not produce any electrical power from fusion. The feasibility is determined by the gain from fusion (efficiency achieved in vaporizing the liner), not by the ability to sustain the reaction continuously, contain the plasma produced by the vaporized lithium liner, or generate electrical power. In other words, it combines all the classical problems we've had trying to produce electrical power from fusion and turns them into advantages for propulsion.

I haven't seen any other fusion propulsion schemes that appear remotely feasible using current technology, but feel free to post whatever you can find.

That's about the extent of what we have on the back burner. These technologies receive minuscule funding compared to conventional chemical propulsion, even though all experimentation and evidence collected suggests these technologies actually work. The only unanswered question is how well these technologies will work in space. Once flown in space, and assuming it works, there is at last the possibility of regular travel to and from the red planet with eminently reasonable transit times.

louis · 2016-11-04 15:19:27

Laser and microwave propulsion look good to me:

http://www.sciencealert.com/nasa-scient … -in-3-days

https://en.wikipedia.org/wiki/Beam-powe … propulsion

The great thing about them is that you don't have to carry your fuel with you against the force of gravity. I think NASA have already got a (v small) space plane flying using such methods.

GW Johnson · 2016-11-05 13:02:50

So what's wrong with the Hall effect electric thrusters we already have, and have flown many times? They're off the shelf, those other things are not. Low thrust for the weight and power, just like all the other electric ideas, but Isp in the 5000 sec class.

Use those alone for applications not needing short flight times. Use them in concert with high-thrust propulsion to shorten flight times further, during the coast between burns.

And then there's two types of gas core nuclear thermal rocket that nobody ever actually did anything substantive with. The closed cycle form with the radioactively-clean exhaust was projected as T/We ~ 5-10 at Isp ~ 1300 sec. The open cycle form with the radioactive exhaust and full regenerative cooling was projected as T/We ~30 at Isp up to 2500 sec. The other open cycle, dirty exhaust form had radiator cooling, which cut T/We ~ 0.1 to 0.01, but with Isp in the 6-10,000 sec range. Definitely NOT on the shelf, but they all three sound like good bets for technology development programs.

There's also the 1950's nuclear pulse propulsion to update. It's not on the shelf either, but it's a very, very good bet for a technology development program. They flew the explosion propulsion idea subscale with ordinary explosives, even though they weren't supposed to, about 1959. It works best with gigantic vehicle sizes: 10,000 tons and up. Isp > 10,000 sec, and it's hard to hold vehicle accelerations to the 2-4 gee range. Vehicles that big are easy to spin for artificial gravity, and are in effect their own radiation shields.

GW

Void · 2016-11-05 16:26:18

I am going to post, and will list other things, but really, I am not pushing any certain technology, rather I choose to make the observation that I would like to be alive 100 years from now to see what technologies would be put to use.

Stuff from another topic:
http://newmars.com/forums/viewtopic.php?id=751
-Harvesting atmosphere from planets like Mars, to provide propulsion mass.
-Magnetic heat shields.
-Fusion pulse rockets.
-Plasma Mass drivers.

And then Tom posted this about Metallic Hydrogen:
http://newmars.com/forums/viewtopic.php?id=7534
I had thought that launching loads from Earth was never going to have a better implementation than what is being matured on the launch pads today. It would seem that 50-100 years from now that might not be true.

And then there is ballistic capture for payloads, which might not be that great for human space flight, but for pre-positioned payloads, and planned routine resupply might be very efficient.

My observation is that spaceflight technology has a long way to go before maturing into a dogma that satisfies best needs.
I am glad about that.

Yes, I know "We need to be "Down To Earth!" about technologies to get to Mars".

You might prefer stuff that can be reasonably mature in 10-20 years.

Last edited by Void (2016-11-05 16:34:44)

kbd512 · 2016-11-05 17:41:07

The only specific technologies I'm pushing are technologies that are substantially better than what we have now. We're essentially limited to low-Isp, high-thrust chemical rockets and high-Isp, low-thrust ion engines. We need better propulsion technologies. The insane cost of going to Mars with these technologies more or less proves that. There's a difference between possibility and practicality.

No one can say with 100% confidence that any given new power or propulsion technology will or won't work. However, I can say with 100% confidence that if we never attempt to obtain something better, we'll never get something better. I sincerely doubt that the people who designed chemical engines and ion engines had a complete understanding of the technology when it was initially developed and implemented, but that didn't stop them from devoting more money and manpower to further development.

Our chemical propulsion development programs have had enormous sums of money and incredible manpower thrown behind them, but specific impulse hasn't significantly improved in decades. Reliability and maintainability has improved, but at the end of the day every chemical rocket we've devised has been extraordinarily expensive and decidedly inefficient.

Our electrical propulsion development programs have also had quite a bit of money and manpower devoted to development, but the Xenon propellant typically used in these systems is every bit as expensive as gold and, like gold, pretty rare. The ion engines offer a marked improvement in specific impulse, but decades after those engines were available the largest payloads so propelled have been small satellites and probes.

We're unlikely to produce a viable replacement for chemical rockets to attain orbital velocity in the near future, but once in orbit we should strive to dramatically reduce or eliminate use of propellants for propulsion. We need more velocity to execute the types of missions we say we want to do than what current technologies make practical, even if it's still possible. The propulsion requirements to achieve our new exploration objectives won't be satisfied by mere refinement to existing technologies. We need to take a hard look at "what's next".

Tom Kalbfus · 2016-11-05 20:42:45

Void wrote:

I am going to post, and will list other things, but really, I am not pushing any certain technology, rather I choose to make the observation that I would like to be alive 100 years from now to see what technologies would be put to use.
Stuff from another topic:
http://newmars.com/forums/viewtopic.php?id=751
-Harvesting atmosphere from planets like Mars, to provide propulsion mass.
-Magnetic heat shields.
-Fusion pulse rockets.
-Plasma Mass drivers.
And then Tom posted this about Metallic Hydrogen:
http://newmars.com/forums/viewtopic.php?id=7534
I had thought that launching loads from Earth was never going to have a better implementation than what is being matured on the launch pads today. It would seem that 50-100 years from now that might not be true.
And then there is ballistic capture for payloads, which might not be that great for human space flight, but for pre-positioned payloads, and planned routine resupply might be very efficient.
My observation is that spaceflight technology has a long way to go before maturing into a dogma that satisfies best needs.
I am glad about that.
Yes, I know "We need to be "Down To Earth!" about technologies to get to Mars".
You might prefer stuff that can be reasonably mature in 10-20 years.

Metallic hydrogen has some other properties as well, superconductivity, we could use that to build a magsail, the article said it was 15 times denser than liquid hydrogen, about 14 cubic meters of the stuff weighs a ton, so that means a cubic meter of metallic hydrogen weighs a bit over a ton, a little more than the density of water. Metallic hydrogen is also monoatomic, its chemical formula is H, and monoatomic hydrogen is its own oxidizer, H + H -> H2 plus energy. the reaction product is molecular hydrogen, which because of its low molecular weight has a high specific impulse, and a temperature of 6000 K, about the temperature of the surface of the Sun. By mixing the exhaust with more hydrogen, we can lower its temperature so that it can be contained within a reaction vessel, but it would enable a single stage to orbit vehicle. Metallic hydrogen is hard to make, but easier than anti-hydrogen, safer to use as well, it is non nuclear so it isn't radioactive, and the exhaust it produces is simple hydrogen, which at the temperature it exits the reaction chamber, will quickly combine with oxygen in our own atmosphere to produce water vapor.

Last edited by Tom Kalbfus (2016-11-05 20:44:37)

SpaceNut · 2016-11-05 21:10:29

kbd512 not sure that I can add much but I notice that the list of technologies on the wish list are very energy consuming at power levels that solar will not do....
Some of the field generations are to bend space time around the craft so that it would slip more easily through it.

Void · 2016-11-06 11:18:00

kbd512's topic is "Breakthrough In-Space Propulsion for Affordable Mars Missions".

It seems to me that I can fit the "Mad Dash Plan" into that, or a "Strongly Protected Plan", if "Breakthroughs" allow it.

They both intend to reduce space medical problems for human travelers.

I am sure that if a Mad Dash Plan becomes possible which does not have the power limitation issues which spacenut has raised, then the Strongly Protected Plan may not be useful anymore as an idea.

However, since I cannot predict what breakthroughs, I will try to build a hybrid plan. (I will "Try").

I will start with Louis's mentioned item: Laser propulsion.
http://www.sciencealert.com/nasa-scient … -in-3-days
Actually for Human flight, I believe the time span is 1 Month. I like this idea because much of the propulsion method is:
Quote:

But instead of photons from the Sun's rays, Lubin's design would be given a push by giant Earth-based lasers.

I think it is clear that it is much easier to obtain infrastructure on the surface of the Earth than anywhere in space, at least at this time. And human resources + their life support.

If you are going to have a radiation shield, you might as well have it be a baton (GW). More of a cue tip shape I would think. Possibly a connecting tube between the two expanded ends. Heavy shielding on the expanded ends.

So, if that works, for this "Hybrid" method, then I want some protective methods as well, to balance it out, since it is to be a hybrid. Radiation shielding:
http://www.space.com/29512-mars-mission … lenge.html
Quote:

1st place ($5,000): George Hitt, assistant professor of physics and nuclear engineering at Khalifa University, United Arab Emirates, for proposing a reusable shield that could be placed in an orbit between Earth and Mars.

That is a bit of a cycling spaceship notion. I do not know if the lasers can aim at it if it is not close to Earth, so I have a gap there.
If not then that puts some damper on it, but it is not a deal killer. But for a "Cycling" radiation shield, you may only need orbital trimming from time to time, and you could use sunlight and gravity assists from Earth, Luna, Mars.

I would have the radiation shield in the form of a Q-Tip shaped baton, GW, which could generate synthetic gravity.
A docking port in the middle of the tube which connects each expanded bulb. Each end to hold a "Gym, radiation shelter, rec room. There would be two, so that if there were personal frictions, it would help to reduce them.

Of course how to associate a solar sail with this will be an issue.

I would have regular robot resupply, by an efficient robotic slow boat method.

And I would have the human spacecraft dock with this thing, and ride with it for a significant portion of the journey, and when the collection of crafts neared Mars, the human craft would do a ballistic capture for efficiency, and the cycling radiation shield would avoid capture and instead try to use a gravitational assist to go into it's next cycle.

Due to the incorporated protective measures, the 1 month trip time should not be a requirement anymore, but the lasers could be used, but you just might not need as much power.

And then there are the other mentioned possibilities mentioned by kbd512, and others. Well, the human ship does not have to be laser pushed, but it might be.

Due to the great number of eventual technological breakthroughs which are likely to happen over time, and the fact that I am not the beast and the brightest, I don't actually think that this is going to be "the" model. It is just one possible model. Don't get your feathers too ruffled over it.

Obviously this is not a first mission structure, it is a structure for repeated transport. It is also nothing like what Elon Musk has in mind.

If it turns out that this post annoys anyone significantly, just say so, I will wipe it out, and not really mind.

Last edited by Void (2016-11-06 12:05:25)

kbd512 · 2016-11-06 16:03:00

The point of this thread was to demonstrate that there are now a variety of technically feasible alternatives to chemical and ion engines that don't require multiple launches of super heavy lift rockets at $1B per flight. If any of the three technologies that I proposed or any of the other technologies that other posters have posed are pursued with a little more funding than what we presently allocate, it's highly likely that one or more of those technologies will bear fruit.

The Q-thrusters and S-thrusters are very low hanging fruit that require very little in the way of advanced technology development. Systems development is required for any propulsion technology, but nothing related to the systems development work is outside the realm of current technological capabilities. Therefore, we should figure out if either or both of these technologies work as advertised. The cost is too low, the time required to implement is too short, and the reward too great to pass up. Unlimited dV from your in-space propulsion system means that even if there is a problem on the surface of Mars and you need to come back, if the mission is planned accordingly you can ascend to orbit, rendezvous with the Mars Transfer Vehicle, and directly abort to Earth at any time.

The low performance projection for Version II of the S-thrusters would enable Dragon V2 to transit to Mars in a week and come back in a week. The high performance projection for Version II of the S-thrusters would enable assured access to Mars and the entirety of the inner solar system at any time, for any mission, by providing 2g acceleration. Obviously manned missions couldn't actually use that capability, but with 1g constant acceleration, artificial gravity is not required and transit time is about one week. We wouldn't want to get to Mars in less than a week, even if we could. If the spacecraft hits a grain of sand at the velocities involved, the effect would be catastrophic.

We're going to witness a race to the bottom of propulsion costs in the near future. No one will pay to deliver propellants or chemical rocket engines for in-space propulsion if there's a viable alternative.

Void · 2016-11-06 21:36:10

Yes, I picked stuff with some familiar themes already in existence. Lasers, Solar Sails, Cycling Radiation Shield (Spaceship).

But those are not really the far out stuff that you mention, the Q-thrusters and S-thrusters and other things.

I actually have some belief in the Q-thrusters. It makes sense to me that if you apply energy to virtual particles you could push against them. Your not getting a free lunch doing that as far as energy and thrust go, you are just dispensing with take along propulsion mass.

I don't understand the S-thrusters tried to look it up but got stuff about steam engines.

A agree with what you say. What if 20 new propulsion methods matured in the not so distant future, and in many cases they could be used in combination. That would really get the human race out of it's strait-jacket.

Last edited by Void (2016-11-06 21:42:33)

Antius · 2016-11-07 05:54:32

Tom Kalbfus wrote:

Void wrote:
I am going to post, and will list other things, but really, I am not pushing any certain technology, rather I choose to make the observation that I would like to be alive 100 years from now to see what technologies would be put to use.
Stuff from another topic:
http://newmars.com/forums/viewtopic.php?id=751
-Harvesting atmosphere from planets like Mars, to provide propulsion mass.
-Magnetic heat shields.
-Fusion pulse rockets.
-Plasma Mass drivers.
And then Tom posted this about Metallic Hydrogen:
http://newmars.com/forums/viewtopic.php?id=7534
I had thought that launching loads from Earth was never going to have a better implementation than what is being matured on the launch pads today. It would seem that 50-100 years from now that might not be true.
And then there is ballistic capture for payloads, which might not be that great for human space flight, but for pre-positioned payloads, and planned routine resupply might be very efficient.
My observation is that spaceflight technology has a long way to go before maturing into a dogma that satisfies best needs.
I am glad about that.
Yes, I know "We need to be "Down To Earth!" about technologies to get to Mars".
You might prefer stuff that can be reasonably mature in 10-20 years.
Metallic hydrogen has some other properties as well, superconductivity, we could use that to build a magsail, the article said it was 15 times denser than liquid hydrogen, about 14 cubic meters of the stuff weighs a ton, so that means a cubic meter of metallic hydrogen weighs a bit over a ton, a little more than the density of water. Metallic hydrogen is also monoatomic, its chemical formula is H, and monoatomic hydrogen is its own oxidizer, H + H -> H2 plus energy. the reaction product is molecular hydrogen, which because of its low molecular weight has a high specific impulse, and a temperature of 6000 K, about the temperature of the surface of the Sun. By mixing the exhaust with more hydrogen, we can lower its temperature so that it can be contained within a reaction vessel, but it would enable a single stage to orbit vehicle. Metallic hydrogen is hard to make, but easier than anti-hydrogen, safer to use as well, it is non nuclear so it isn't radioactive, and the exhaust it produces is simple hydrogen, which at the temperature it exits the reaction chamber, will quickly combine with oxygen in our own atmosphere to produce water vapor.

Question: Metallic hydrogen forms at pressures of ~10E6 bar. Does it cease to be metallic when that pressure is removed? i.e. is it stable under standard conditions? If not, it would appear to have limited utility.

Last edited by Antius (2016-11-07 05:55:20)

kbd512 · 2016-11-07 11:51:47

Here's a pretty good article of what we can achieve with the Q-thrusters without improving upon current power generation technology:

Human Outer Solar System Exploration via Q-Thruster Technology

With 1MWe of input power, we can go directly to Mars any time we want, no matter what the orbital phasing of Earth and Mars is. The power requirement is fairly high, but not unachievable using current solar panel technology. That's 3,333kg worth of solar panels using actual production solar panels that are and have been flown in space. Obviously the actual mass allocation requirement is higher to achieve the same performance at Mars, but even with 5,000kg allocated for solar panels, we're not talking about significant mass. The actual complete propulsion device would have a mass of something like 10t, which means Falcon 9 rockets could easily deliver the cycler devices to orbit.

We only need two cycler devices, maybe three maximum to have a hot spare in LEO. Falcon Heavies would then deliver 50t cargo blocks to orbit, for a total launch services cost of $100M (assuming no first stage reusability). That means 400t worth of cargo could be delivered to Mars orbit for the cost of 1 SLS flight in the two years run up to a human landing on Mars. NASA can afford $2B per year for SLS, so for half the price we could actually deliver everything required for a "safe" Mars mission (orbital station, multiple MSH's, multiple MAV's, multiple solar arrays and fuel cells, multiple rovers) for approximately the same cost as the SLS program.

Two cycler devices mean a cycler is delivers cargo to Mars every 90 days since round trip time is 180 days, hence the 400t pre-positioned cargo figure. The actual outbound flight time is 75 days, but the return flight is 100-110 days. That's still a long trip, but ISS stays seem commonly average 6 months to 1 year now. Since we can come and go as we please, the total mission time is one year. I would like to reiterate that this is using lab demonstrated technology with no advancement in thrust level or power conversion efficiency. The technology we have in hand right now enables this new mission architecture paradigm.

If Version II S-thrusters become operational and only perform to the low-end of what superconducting electromagnets are capable of, maximum transit time to Mars is one week, irrespective of orbital phasing, and power requirements drop like a rock. We're talking about the ability of a Dragon spacecraft to deliver a crew of 4 to Mars in less than a week. Mission times average just 6 months, equivalent to a "short" ISS mission. We come and go as we please because orbital phasing is meaningless over the distances we have to cover with the acceleration we can achieve. If someone gets sick or injured on Mars, we can feasibly bring that crew member home in a matter of days.

At the high end of the performance spectrum for Version II S-thrusters, propellant-less ascent to orbit becomes possible and space flight will be as safe and routine as flying on passenger aircraft. For purposes of Mars colonization, transit times of one week or less make a Mars colony of one million people a feasible feat of engineering and reasonably cost effective undertaking. More importantly, raw materials for building the colony will come from the asteroids near Mars and a very lucrative precious metals trade with Earth becomes feasible. Why would you spend time and money trying to dig iron out of the ground on Mars or Earth, when you could fly to an asteroid made of pure iron, start melting chunks of it, and carry the product back to the gravity well where you want to use it? At some point, it will become cost-ineffective to mine resources in the traditional sense when asteroids are discovered that have millions of tons of product that anyone with the technology can apply a little heat to and cart off.

Void · 2016-11-07 12:43:25

kdb512, your pdf not coming up. Not your fault, as it does not come up elsewhere either, but I will put this here.
https://ntrs.nasa.gov/search.jsp?R=20140013174
Frankly I am excited, but other than understanding push, and virtual particles, I am in over my head.

Last edited by Void (2016-11-07 12:47:08)

Void · 2016-11-07 12:48:40

Antius, I am utterly ignorant per metallic Hydrogen, starting to look into it since Tom posted.
Have this: https://en.wikipedia.org/wiki/Metallic_hydrogen
Interestingly:https://en.wikipedia.org/wiki/Metallic_hydrogen#Lithium_doping_reduces_requisite_pressure
Quote:

Lithium doping reduces requisite pressure[edit]
In 2009, Zurek et al. predicted that the alloy LiH6 would be a stable metal at only 1⁄4 of the pressure required to metallize hydrogen, and that similar effects should hold for alloys of type LiHn and possibly other alloys of type ?Lin.[15]

Back to Hydrogen as a metal: https://www.yahoo.com/news/m/0de4449b-6 … en-is.html
quote:

Metallic hydrogen is metastable could be used as superlightweight structural material for floating cities

Frankly I read the official news, and I read the crazy news. Don't believe I have much truth. So, some grains of salt as a caution.

Last edited by Void (2016-11-07 12:56:17)

kbd512 · 2016-11-07 21:07:19

Void wrote:

kdb512, your pdf not coming up. Not your fault, as it does not come up elsewhere either, but I will put this here.
https://ntrs.nasa.gov/search.jsp?R=20140013174
Frankly I am excited, but other than understanding push, and virtual particles, I am in over my head.

Void,

That's weird because it comes up in my browser. However, I've had problems with the NTRS system every so often. The link you posted is directed at the same document.

For NASA's part, I still can't believe that there isn't more funding for this technology. For the capability provided, I'd expect a near religious response from the agency. We're unlikely to acquire better in-space propulsion technology than this within our lifetimes.

Void · 2016-11-07 21:22:24

kbd512,

I'm really just trouble. Best to not bother, but:

Quote:
"I'd expect a near religious response from the agency."

Yes, and that is the sort of response you should expect from them.

Dogma. The Vatican of space travel. It has some big value, and causes some big trouble.

Have you noticed that the really out there ideas seem to come from outside of the power center?

Don't get yourself burned at the stake!

Last edited by Void (2016-11-07 21:24:17)

Tom Kalbfus · 2016-11-08 00:18:02

Antius wrote:

Tom Kalbfus wrote:
Void wrote:
I am going to post, and will list other things, but really, I am not pushing any certain technology, rather I choose to make the observation that I would like to be alive 100 years from now to see what technologies would be put to use.
Stuff from another topic:
http://newmars.com/forums/viewtopic.php?id=751
-Harvesting atmosphere from planets like Mars, to provide propulsion mass.
-Magnetic heat shields.
-Fusion pulse rockets.
-Plasma Mass drivers.
And then Tom posted this about Metallic Hydrogen:
http://newmars.com/forums/viewtopic.php?id=7534
I had thought that launching loads from Earth was never going to have a better implementation than what is being matured on the launch pads today. It would seem that 50-100 years from now that might not be true.
And then there is ballistic capture for payloads, which might not be that great for human space flight, but for pre-positioned payloads, and planned routine resupply might be very efficient.
My observation is that spaceflight technology has a long way to go before maturing into a dogma that satisfies best needs.
I am glad about that.
Yes, I know "We need to be "Down To Earth!" about technologies to get to Mars".
You might prefer stuff that can be reasonably mature in 10-20 years.
Metallic hydrogen has some other properties as well, superconductivity, we could use that to build a magsail, the article said it was 15 times denser than liquid hydrogen, about 14 cubic meters of the stuff weighs a ton, so that means a cubic meter of metallic hydrogen weighs a bit over a ton, a little more than the density of water. Metallic hydrogen is also monoatomic, its chemical formula is H, and monoatomic hydrogen is its own oxidizer, H + H -> H2 plus energy. the reaction product is molecular hydrogen, which because of its low molecular weight has a high specific impulse, and a temperature of 6000 K, about the temperature of the surface of the Sun. By mixing the exhaust with more hydrogen, we can lower its temperature so that it can be contained within a reaction vessel, but it would enable a single stage to orbit vehicle. Metallic hydrogen is hard to make, but easier than anti-hydrogen, safer to use as well, it is non nuclear so it isn't radioactive, and the exhaust it produces is simple hydrogen, which at the temperature it exits the reaction chamber, will quickly combine with oxygen in our own atmosphere to produce water vapor.
Question: Metallic hydrogen forms at pressures of ~10E6 bar. Does it cease to be metallic when that pressure is removed? i.e. is it stable under standard conditions? If not, it would appear to have limited utility.

I think it does, but if it does, it would be very explosive, since it reacts with itself. It forms a crystal lattice of monoatomic hydrogen, if you heat it above a certain temperature, hydrogen atoms would break out of the crystal lattice and react with each other to form molecular hydrogen and releasing a tremendous amount of energy while doing so, this energy would heat the remainder of the crystal, creating a chain reaction leading to an explosion! So if every we produced this stuff and it was stable, we would have to figure out how to react a little bit of it at a time, so we can have a rocket instead of a bomb!

kbd512 · 2016-11-08 10:51:19

Tom Kalbfus wrote:

I think it does, but if it does, it would be very explosive, since it reacts with itself. It forms a crystal lattice of monoatomic hydrogen, if you heat it above a certain temperature, hydrogen atoms would break out of the crystal lattice and react with each other to form molecular hydrogen and releasing a tremendous amount of energy while doing so, this energy would heat the remainder of the crystal, creating a chain reaction leading to an explosion! So if every we produced this stuff and it was stable, we would have to figure out how to react a little bit of it at a time, so we can have a rocket instead of a bomb!

If metallic hydrogen is metastable after the pressure is released, it could potentially be useful as a sort of super chemical propellant for rockets that enables greatly reduced tankage volumes, and thus mass, for storing whatever quantity of propellant is required to deliver a given payload mass to orbit. Isp's as high or even higher than solid core NTR's are possible, at which point there's little point in dealing with radioactive materials and low thrust-to-weight ratios of NTR's.

I would think we'd have a tank of metallic hydrogen comprised of sand granule sized particles pressurized with gaseous hydrogen from a liquid hydrogen tank. The gas would feed the granules into the combustion chamber, the LH2 would provide regenerative cooling for the nozzle and be fed into the combustion chamber where a heating element would catalyze the reaction. It's a simple pressure fed rocket.

The questions that have to be answered are:

1. Is metallic hydrogen stable enough for use as rocket fuel?

2. Can we devise a cost effective manufacturing method that can produce multiple kg's of fuel per hour.

Terraformer · 2016-11-08 12:18:18

You better be launching from the sea, and have a very good crew escape system... I don't think you'd have that much time if a tank of metallic hydrogen went off...

kbd512 · 2016-11-08 14:09:32

Terraformer,

I think it'd make a lot more sense to use MH propellant for cargo than humans. The energy that MH can rapidly release is too dangerous to use with humans present. The capsules can continue to launch on small commodity rockets. That said, just imagine entire super heavy lift vehicles that can fit inside the barge that NASA uses for the SLS core stage.

Void · 2016-11-09 12:33:03

Q-Thrusters and Sulfur Concrete (From the Moon?)

The new Prez...

http://spacenews.com/what-a-trump-admin … for-space/
Quote:

Walker suggested a Trump administration could create a bigger role for the moon in NASA’s space exploration plans than today, when the agency has no plans for a human return to the lunar surface.

So, I am hoping that we could get some high tech results from some lower tech materials.

Specifically, if one idea being pondered is a re-usable radiation shield, perhaps Sulfur concrete shells with a tensile netting for re-enforcement, propelled by Q-Thrusters is a good marriage. Maybe the Sulfur concrete materials at least in part from the Moon (The Sulfur at least), and if more economical, the aggregate from near Earth asteroids.

To protect the tensile netting, and to moderate potential high temperatures, the shells could be wrapped in a protective foil like material. And of course there would be no harm in regular insulation use to moderate temperature swings on the outside.

I am of course hoping that large pressure shells can be created from what might otherwise only be radiation shields.

And I am hoping that very large doors can be built into them sealed and unsealed at the seams by the melting and solidification of Sulfur. This would be done only to bring in or out large objects, or payloads of ore to be processed. As mentioned before, such doors and the shells would be re-enforced with tensile netting protected by foil/insulation methods.

The Sulfur concrete may be cheaper to build shells from in this way than manufactured metals.

Obviously, if Q-Thrusters do not work, then you want a lighter material. But if you have thrust using virtual particles, as propellant, and do not have to resupply the shell constantly with hard to procure normal propellant, then it becomes much more attractive I think. And yes even cycling spaceships begin to make more sense if you have Q-Thrusters that work.

Or the shells manufactured in the Earth/Luna location could be towed to the asteroid belt and Phobos, Demos. To provide pressurized environments to process bulk ores/dirt.

If Q-Thrusters work.

I hope everyone is OK, it is very quiet.

Last edited by Void (2016-11-09 12:53:26)

Terraformer · 2016-11-09 16:06:46

Still here. I meant to check the forums earlier, but... it's been a strange day.

kbd512 · 2016-11-09 19:33:48

What's strange about today, Terraformer?

It's Wednesday. More importantly, SpaceX figured out what happened to their rocket, science is still moving technology forward, and the world did not end just because we elected our next President. All election day nonsense aside, we're on the other side of it. We won't have to hear about it for at least another three years, or so I hope. My most fervent wish is that ALL of our politicians work together to move us forward as a country and that we can put aside our petty differences to accomplish something worthwhile. We have a long list of problems to solve that's not getting any shorter.

On a more personal note, I hope everyone here can set aside political differences and re-focus on cracking this diamond hard problem of making humanity interplanetary and interstellar.

SpaceNut · 2016-11-10 17:53:27

The last 2 posts have been moved due to political conversation....Please continue there....

Lets stay focussed on the technology that will make it possible to go to Mars....

Thanks You

kbd512 · 2016-11-11 02:40:59

SpaceNut,

Sorry about that. I'm tired of people fixating on problems that only exist between their ears when there are so many actual problems that haven't been addressed.

Back on topic.

The point here is pretty simple, but I'm not sure those at NASA have ceded it. If any of the technologies listed here can be made to work passably well, we're assured affordable and reliable access to the entire solar system. The reward is worth the risk.

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