People transport by leapfrog depots, a faster spiral orbit I hope.

Void · 2018-02-09 19:45:20

I can see that some very impressive converstation is occuring on other topics. I want to be careful not to muddy them up with what I am going to speculate on here, so I will start a new topic.
If the experts decide that what I start is just not that good, I will be happy to work with the moderators, and others to remove these materials.

Grypd said on the topic:
Quote:

Index
» Interplanetary transportation
» Falcon Heavy-moving forward & what's next?

Post #2:
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The fact that SPACE X expected to lose the whole vehicle but in the end only lost the upper stage is incredibly impressive
of course the two boosters landing as they did was impressive

And I agree.

O.F. has suggested moving external tanks to Mars, by ion rocket, I believe that the intention is to get the efficiency of ion rockets, and the responsiveness of chemical rockets.

I would like to try to expand on that. My intention is to try to leverage that idea, by multiplying the instances of depots, and using a spiral orbit method that is on steroids, to more quickly move between Earth and Mars.

The boosters landing as they did is evidence that robotic spacecraft are only getting more powerful, and I think we can expect that to follow "Moore's Law", or at least I suspect it might.

https://en.wikipedia.org/wiki/Moore%27s_law

To relax members, who love SpaceX's plan for four BFR's to Mars, I state that I am not trying to rewrite that plan. I am rather considering if Elon Musk wants to move 1,000,000 people to Mars, how can efficiency and redundant safety be improved above that plan, later on?

Well, for that I would want to segment the trip. Just an arbitrary number 10 depots. The passenger ship stopping off at each of them along the way. They, the depots, being dynamic devices, they would not stay in one place, but the passenger ship would be able to overtake them in spiral orbits.

Probably these depots, would be replenished continually. I do not have a hard decision on how much of their hardware would be re-usable, or how many times. Maybe the engine sections only? Maybe the whole things.

It would certainly be complicated choreography. But robots and software if properly debugged, should be able to master the situation.

If the Neumann method of Ion drive turns out to be successful, then that would be a option, but I think that if you set out fuel depots with metal propellant, and leapfrogged from one to another, it would involve dangerous movements of solid materials, perhaps spacewalks. I would like to utilize the Neumann drive and yet also avoid the dangers.

http://neumannspace.com/

So for the moment I will leave the Neumann drive behind, but will pick it up again after I explain what I think might be helpful:
"Spiral Chemical Method".

I will explain the above, and then suggest a hybrid between Neumann drive and "Spiral Chemical Method".

The trouble of chemical propulsion is "How do you keep the mass down?".

I am thinking you do it with small engines. Also by utilizing the boil off in a continuous manner.

If you use the SpaceX methods you super chill the propellants, before activation of the machines, to provide propellants that need more space. So, before you have to deal with boil off, you will have to deal with propellant expansion or the tanks will burst.
So, in the beginning your chemical engines will need to burn off as much propellant expansion as is necessary, to prevent the rupturing of tanks. After, that they can burn the boil off in a continuous manner, doing a spiral up in the case of moving from Earth to Mars.

SpaceX is developing what they claim is a reliable method to dock their spacecraft to the international space station.

My feeling is that if you have spiraling fuel depots two of them could be attached to the crewed craft at all times. The crewed craft would be able to overtake the spiraling depots since they would be thrusting at a lower level. At overtaking each depot between Earth and Mars, a less full depot would be disconnected, and a rather more full overtaken one would be connected. No refueling but of course the dangers of docking.

OK, so the whole intention here is to reduce the whole time mass of the ship. You start out with two fuel depots, and you exchange them as you go. That should allow you to travel between Earth an Mars in a spiral orbit at a faster rate.

We hope to protect humans from an some extent of damages (Radiation, low gravity, other risks in solar orbit).

But factoring in the Neumann drive, we might expect to join a chemical depot to a Neumann drive device. Using the burn off of excess fuel, to propel the ship, and to also use the Neumann drive to also help propel the "Barge".

So the crewed ship would overtake each depot on the spiral up to Mars, and since it was expecting to be resupplied, it would be light in mass.

This could present a danger, as if you did not reach then next depot, your fate could be very grim. However, I anticipate a vast array of such depots Neumann Drive/Small Engine Chemical Depot being constantly re-deployed robotically. Therefore, there should be vast resources, to rescue a crewed vessel, if it meets with a unanticipated and unfortunate mishap.

I am anticipating that some type of ballistic capture might also be involved.

OK then that is sufficient, you may attack.

Last edited by Void (2018-02-09 20:27:53)

SpaceNut · 2018-02-09 20:08:41

Having fuel depots as delivered from earth to remote locations are for several specific reasons. First for mars is its less of a burden on the mars surface insitu processing and relaunch that makes it harder to deliver the quantity of fuel back to orbit for mars uses. It is a better fit to only make just what we need to go back to orbit insitu where we couple back onto a fuel tank and then go.

The ION use will also create depots of other resources as well such as water, Oxygen, foods, buffer gasses ect...in the same locations that fuel is delivered to. Another natural system to send are the nuclear power plants that sit quitely until we need them to help get ready for the next to park along side of it.

The use of ION drives to move ores for use in earth orbit as well as onto other locations not just Mars as well will need to develope toeholds, footholds and finally the strong presence of colony support....

Void · 2018-02-09 20:10:52

OK, I am going to edit this post and "Friendly it up a bit".

I am trying to come up with a method which gets people quickly from Earth to Mars, therefore reducing the exposure to radiation and low gravity. I think it may be possible by leveraging anticipated technological progresses. Hopefully using a spiral orbit method, but on steroids. Hopefully adding redundant safety/rescue methods. I will continue with my post #1.

When Insitu becomes real for Mars, these Depots could be resupplied from the Mars system (Mars>Phobos>Demos).

When Insitu becomes possible on the Moon, primarily with telepresence, these Depots could be resupplied from the Earth/Moon system.

Eventually, it may be that other Insitu methods dealing with other solar system objects could be resupply methods. Say asteroids.

But to begin with the resupply to the Depot-Robotic-Thrust systems would be strictly from LEO.

It would be decided what should be recycled back to LEO for refurbishment, the Neumann system?, the Chemical Tanks?, the Chemical Engine section?

As I have said not only is there a desire to quicken a spiral method to reduce exposure to radiation, but to lessen the other space illness exposures.

Having multiple robots, with both Ion and small thruster chemical drives, will offer methods of rescue which otherwise will not exist.

I anticipate that since the chemical engines will be small, there can be redundant numbers of them. In other words a whole backup thruster system, maybe even two.

If a ship carrying passengers got in trouble, a most near "Barge" could activate all usable chemical thrusters, to most quickly intercept the injured ship, bringing supplies, and methods of propulsion to it. Helping to rescue the situation.

And as I have said this is not the beginning method, but possibly how you move vast numbers of humans from locations of greater population to locations of lesser population, such as Mars, as it is now.

While of course cost is an issue, the recycling of hardware is currently the method which is being cultivated in order to bring costs down. This cost, being a money cost.

The other costs such as human health and safety will be addressed by having the equivalent of 10 habitable planets to visit on the way to Mars. That is my arbitrary 10 leapfrogs to dynamic (not stationary) depots, in spiraling sun orbit.

Done with this post for now, comments welcome.

Last edited by Void (2018-02-10 05:26:18)

SpaceNut · 2018-02-10 18:03:07

Chemical rockets can not change how they work just because we would like them to and niether will the momentum laws of mass acceleration.
https://en.wikipedia.org/wiki/Transit_o … _from_Mars

Types of mission profiles man has capability to do

This is GW's Fast Transit To and From Mars

There is a trade off of more fuel mass to transit faster versus the payload and when fuel is not increased its the power used to make the exhaust exit faster that is increased which also has the same effects on payloads...

Rapid Mars Transits With Exhaust-Modulated Plasma Propulsion

Fast and Robust Human Missions to Mars with Advanced Nuclear Electric Power and VASIMR Propulsion

Of course with any developig technology you must give it a try.
NASA eyes ion engines for Mars orbiter launching in 2022

Ion engines produce just a whisper of thrust, using electric power to ionize atoms of a neutral gas and spit out the particles at high speed. While the drive given by the thrusters is barely noticeable in one instant, they can operate for months or years, burning scant fuel compared to traditional chemical rockets.

Void · 2018-02-10 18:08:08

I don't believe you get it yet.

Let me explain it in another way.

Suppose you start with a crewed ship with two boosters, each booster having only 1/10th of the fuel and Oxygen that you need to get to Mars.
You start much lighter, because the tankage to hold 1/5th of the fuel and Oxygen is smaller. The amount of fuel is smaller. The amount of Oxygen is smaller. You are also going to use much smaller engines than normally would be used, so the engine mass very likely would be smaller. You are not going to attempt a Hohmann transfer method, or a typical Ballistic transfer. You are going to do a spiral method, with chemical boosters. Chemical boosters that will be put in place both by ion propulsion, and by burning off the expansion of super cooled fuels at first and also later the boil off.

Notice that previously I gave an arbitrary value of 10 encounters with other identical boosters along the way.

So you have a safety margin with you because you have 1/5th the chemical propulsion mass you need to get to Mars. You only empty the equivalent of 1 booster on the way to pick up the next one. So if something goes wrong, you have reserves.

Enter the Neumann Ion Drive:
http://neumannspace.com/
Quote:

The science
The Neumann Drive is a revolutionary, patented solar-electric ion drive. It uses a pulsed cathodic arc technology, paired with a solid fuel rod, which generates more specific impulse than NASA’s HIPEP thruster. The Neumann Drive can run on a variety of solid metallic fuels, the exact makeup of which varies the amount of thrust and specific impulse generated. This means that the Neumann Drive can run on nearly any metal likely to be found in asteroids, as well as on sintered-down space junk. So not only can you go further with a Neumann Drive, but you can refuel with whatever you find when you get there.

So each Neumann drive ship will be primed to bring a filled booster out to the intercept location, and to carry an empty back for reuse, if that is what is desired. The Neumann drive ship will be assisted in propulsion on the way out by the filled booster, because as the propulsion mass warms up in the booster, the expansion of it must be released, so you might as well burn it in a small engine.

So you left LEO with 2 ea 1/10th boosters, and you overtake the first one to pick up. You take the intercepted booster from the Neumann ship, and then attach your empty to the Neumann ship, the Neumann robotic ship carries it away, and you thrust with your almost full new booster.

So you overtake each booster and make the exchange.
So instead of making a large magnitude burn with large engines at the beginning of the trip, you more or less thrust the whole way there with tiny engines.

The your propulsion mass not counting the crew section is 1/5th to 1/10th of what otherwise would need to be the mass of a traditional method during each segment of the journey. When you picked up a new booster, you would be at 1/5th, as you got towards the next one you would be at 1/10th.

THIS METHOD WOULD BE USED MUCH LATER THAN THE FIRST TRIPS TO MARS. IT MIGHT BE USED TO TRANSPORT THE BULK OF THE 1,000,000 PEOPLE THAT ELON MUSK WANTS TO START A CIVILATION ON MARS WITH.

It should also be obvious that although this method is complicated, you also have some methods of rescue if you have an Apollo 13 mishap. You have multiple boosters on the way with engines, you have Neumann Drive ships along the way.

Probably there would be many crew ships traveling at the same time with their own scheduled booster assists.

And finally in that environment most likely there would be something like the coast guard for ships in trouble, robots with high thrust capability which on rare occasions would be used to provide special assistance if possible.

That's enough.

If it makes sense to put fuel tanks around Mars by electric rocket, it might make sense to do this.

You may reply.

Last edited by Void (2018-02-10 18:35:19)

SpaceNut · 2018-02-10 19:35:51

This particular documents starts out like a college paper but relates Selection Criteria for the Rocket Engine System Design and Overview on the Principles Relevant to the Use of Nuclear Power Sources in Outer Space

You are going to do a spiral method, with chemical boosters

Ah a pulsed engine burst to move the ship with each firing that additively speeds the ship to mars. Which is simular to the https://en.wikipedia.org/wiki/Pulse_detonation_engine but works in space like https://www.nasa.gov/centers/marshall/p … tonate.pdf and simular to the accelerated atoms New research could power rocket trip to Mars in weeks, not months

Back to spiral that is is ok for cargo but not crew as it is not a straight line and the distance will not help to get the ship to mars faster.

Fuel depots on the way means we can not slow down for them and matching speed may be possible if they are timed just right but thats a big if as we are trying to get to mars faster as once we are more than half way there the depot is moving to fast to catch it.

Vapor boil off will not work on a fluid style engine.

Void · 2018-02-10 20:02:12

Now I am going to grant you that the idea is very complicated if it even works.

But I exposed this site to this a while back:
Enter the Neumann Ion Drive:
http://neumannspace.com/

Quote:

Back to spiral that is is ok for cargo but not crew as it is not a straight line and the distance will not help to get the ship to mars faster.

And I recall that G.W. said "We could just spiral out" or something like that so if I understood correctly he believed a crewed mission was possible by spiraling. Of course it will require power supplies.

There are robots that can do this:
https://mashable.com/2018/02/06/spacex- … KaGTvi9Oq9

Now I am anticipating that there will be robotics sophisticated enough to place a dynamic progression much later on.

Quote:

Vapor boil off will not work on a fluid style engine.

That's good to know, thanks, I could argue that a tiny engine for the purpose might be possible to design, but lets drop that item at least for now.

Quote:

Fuel depots on the way means we can not slow down for them and matching speed may be possible if they are timed just right but thats a big if as we are trying to get to mars faster as once we are more than half way there the depot is moving to fast to catch it.

I have a question for you and it is not to be a jerk. It is to learn.

Logic (Maybe very bad logic) tells me that an ion rocket can catch Mars. Granted it might be that Martial gravitation helps.

Here is my question: If you shut down the ion rocket of a ship headed for Mars before it arrives at Mars, and don't ever turn it back on, what is the proper description of the shape of the solar orbit it will have? More or less circular or very dominantly elliptical?

But in my searching, I found this, so the point is moot. I will drop my case, at least for now, and go with something that NASA is proposing instead. And it is related to what I tried to conceive.
https://newatlas.com/hybrid-solar-elect … asa/24791/
Quote:

NASA examines hybrid solar-electric propulsion for manned space missions

Strange and his team believe that the answer lies in combining these methods into a much more efficient and flexible system. The basic plan is to use heavy lifting rockets like NASA’s Space Launch System to boost components for a ship into low-Earth orbit. Once assembled and fueled, the SEP system would slowly push the unmanned vehicle into an elliptical high-Earth orbit. Once there, the crew would rendezvous using chemical rockets, which would also be used to push the vehicle out of orbit. After that, the SEP would propel the ship to its destination.

So...It does seem that someone thinks a rendezvous in Earth orbit is possible. And they are doing it in an elliptical path. I have trouble understanding why it could not be done in solar orbit?

But the point is moot. Go ahead and remind me why I am wrong but it does not matter. There are persons examining the concept of hybrid missions already and they are rocket scientists. If there is a way to do it with very smart robotic rockets later on, they will figure it out. I should go ahead and find something better for myself to do instead.

I am done. You can keep this topic, or wipe it I don't care.

Last edited by Void (2018-02-10 20:46:46)

Terraformer · 2018-02-11 03:29:50

Are you thinking that the boosters would be spread out between here and Mars, and rockets would pick them up along the way? I don't think it works that way. If you don't get enough speed at the start, you won't leave Earth's gravity at all, or enter into a Mars transfer orbit.

It's a lot easier, anyway, to drop from EML1 and use a gravitational assist. That can get the trip time down to 3 months with chemical rockets.

Void · 2018-02-11 08:14:19

Quote:

It's a lot easier, anyway, to drop from EML1 and use a gravitational assist. That can get the trip time down to 3 months with chemical rockets.

Well, since the pain must continue, why don't you explain that a bit more, so that I can learn it.

......

For those who don't understand I will say that I don't feel as bad as you might think. I have discovered that Hybrid methods have been studied by real rocket science people. While a spiral out and refuel as you go is very likely to be unattainable, I'm happy to learn some stuff.

I repeat:
https://newatlas.com/hybrid-solar-elect … asa/24791/
Quote:

NASA examines hybrid solar-electric propulsion for manned space missions

Strange and his team believe that the answer lies in combining these methods into a much more efficient and flexible system. The basic plan is to use heavy lifting rockets like NASA’s Space Launch System to boost components for a ship into low-Earth orbit. Once assembled and fueled, the SEP system would slowly push the unmanned vehicle into an elliptical high-Earth orbit. Once there, the crew would rendezvous using chemical rockets, which would also be used to push the vehicle out of orbit. After that, the SEP would propel the ship to its destination.

So, Spacenut has worked to educate me some, but he was wrong that ion propulsion for humans is out of the question. It has been considered in a Hybrid method. Of course he was thinking only of the ion propulsion.

I learned that if you were to utilize boil off for propulsion you would need a new engine. Most likely a tiny one.

For the Hybrid mission method mentioned above, however, I think it would still be valid to burn off the excess fluid if it expanded.
That is if you super chilled the Oxygen and Methane (Supposing you were using Methane), and it warmed up and expanded, you would need to utilize some of it to keep the tanks from bursting. So, the spin up to Earth elliptical orbit would not only be done with an Ion rocket, but also with that excess propellant.

......

So, I will drop the notion of 10 arbitrary fuel depots, but will look at a single one with a 1.5 year elliptical sun orbit, that intercepts the Earth periodically. Maybe that being simpler, and looking something like the Hybrid method mentioned above could be considered.

A depot of that kind could possibly be positioned by Ion propulsion, and burn off of excess propellants, and perhaps even gravity assists. This would be a cycling spaceship, but without humans. A depot.
Quote:

Once there, the crew would rendezvous using chemical rockets, which would also be used to push the vehicle out of orbit. After that, the SEP would propel the ship to its destination.

So, you would do the hybrid maneuver that was mentioned in the article.
1) That would get a depot into Earth elliptical orbit. Essentially using the efficiency of Ion propulsion leveraged to provide the strength of chemical propulsion.
2) Get the crew through the Van Allen belts in a hurry. I think that is a useful medical protection from radiation.
3) Save time, and reduce the consumption of resources that people need to survive.

But if the 1.5 year Solar Cycling Depot could also be integrated into the plan, more leverage could be applied. Getting efficiency out of an Ion drive again, and probably the potential to shorten the travel time.

I am not sure this is what I would want to do. The costs of equipment might eat up the efficiencies produced. Might not be worth it. But I wonder if it would be possible to do.

A ~540 day Solar Cycling Depot and Mars orbit being about 686.98 days.

Weather it worked or not, I am inclined to believe that since it was a notion for later on, there will some kind of propulsion system coming up, perhaps nuclear of some kind that will make it obsolete anyway.

Last edited by Void (2018-02-11 13:02:00)

Void · 2018-02-11 08:48:32

Terraformer Quote:

It's a lot easier, anyway, to drop from EML1 and use a gravitational assist. That can get the trip time down to 3 months with chemical rockets.

Please explain with more detail.

Terraformer · 2018-02-11 09:47:49

A spacecraft falling from Lagrange point 1 will be travelling close to escape velocity when it reaches it's lowest point. By using the Oberth effect, a 1.2km/s burn can provide the same delta-V as, I think, a 3.6km/s burn from LEO, enough for a 6 month journey to Mars. By instead using a 3.6km/s burn, the journey time can be reduced to 3 months. The actual calculations are buried in a post somewhere on this forum. This doesn't, however, include fuel for slowing down...

Void · 2018-02-11 09:52:46

Thanks Terraformer, I will see if I can digest that. It looks pretty interesting.

I'm not making any serious proposals, but it does seem to me that something like that if possible can be coupled to Ballistic Capture. And a Fuel Depot in Martian orbit (Put there with Ion drive and Ballistic Capture).

While Propulsion savings with Ballistic Capture are not possible outside of Ion propulsion methods, Ballistic Capture frees up departure times, where using Hohmann transfer is very rigid.

Of course where your plan gets the mission down to 3 Months, using Ballistic Capture is likely to add some flight time to the trip.
There are tradeoffs.

It is interesting though with a Hybrid method you would be finishing your trip to Mars with Ion propulsion. I wonder if there would be propulsion mass savings then.

I consider the Hohmann transfer to be quite dangerous. Also the harsh aeroburn.

With Ballistic Capture, you can enter orbit without Aeroburn, and then later do a much more gentile aeroburn with just a lander craft.

If this were to be a people moving system, then most likely a lander would not be included. BFR would already have set up a base on Mars, and there would be lander craft available at Mars. Perhaps in the beginning those lander craft would be cycled back to the Earth by Ion craft for serious maintenance periodically.

I like this better also because it might allow you to have some minimal synthetic gravity during the transit Earth/Moon>Mars and vice versa.

Like I have said elsewhere, just enough synthetic gravity for easy waste disposal would be my objective. It might even help some of the health and possible mental health issues.

With all of that your bulk of supplies and the bulk of the ship do not have to do an aeroburn.

......

1) Many supplies delivered to Mars orbit by robot Ion propulsion/Ballistic Capture.
2) Maybe 1.5 year? Solar Cycling Depot could also be integrated into the plan, but I am actually sort of against it is not wrong to consider it though. It does add dangerous complexity, and I guess unless the device could be reused repeatedly the costs would be undesirable.
3) So then some type of Earth/Moon Hybrid starting method. And then for my tastes Ballistic Capture. (The crewed mission).

But the Neumann drive needs improvements if it is to be used. Next post.

Last edited by Void (2018-02-11 10:30:37)

Void · 2018-02-11 09:55:00

In order to be fair, and also to bury my mistakes, I will post some information about the Neumann drive vs. more typical Ion drives.

I think it's weakness is it's draw on power relative to the propulsion it provides.

However, it is a new invention. Typically, first you do it at all, then you try to make it elegant.

https://newatlas.com/neumann-ion-drive- … ine/39490/

Towards the end of the article, intended improvement targets are mentioned.

Last edited by Void (2018-02-11 09:58:17)

SpaceNut · 2018-02-11 12:16:30

Escape_velocity

The escape velocity is the minimum speed needed for an object to "break free" from the gravitational attraction of a massive body. The escape velocity from Earth is about 40,270 km/h (25,020 mph).

Using EDS chemical boost from the moons circa lunar swing and then a slingshot around earth will make the transit faster but that means staging for the mission design. Time to the moon and back around a week.

Viod, the current ability of ION drive is why that men should not be considered. The Hall thruster is currently being used on a number of unmanned spacecraft, such as NASA’s Deep Space 1 and Dawn, they use electrically charged atoms of cesium or xenon for thrust instead of burning chemicals. The SEPs suffer from extremely low thrust – about the same as the weight of a coin resting on a table. In space, this is enough to move a vehicle at incredible speeds, but it also takes a very long time. Just spiraling out of Earth orbit can takes weeks or even months.

Dawn mission solar ION propulsion profile

Launch from Cape Canaveral on a Delta 2 (7925-H) on a four year heliocentric cruise including a Mars flyby to within 542 km of the surface and gravity assist.

The two 2.3 x 8.3 meter solar arrays, composed of InGaP/InGaAs/Ge triple-junction cells, provide 10.3 kW at 1 AU (1.3 kW at end-of-life at 3 AU) to drive the spacecraft (22-35 V) and the solar electric ion propulsion system (80-140 V). Power is stored in a 35 Ah NiH2 battery. The ion propulsion consists of three ion thrusters and is based on the Deep Space 1 spacecraft ion drive, using xenon which is ionized and accelerated by electrodes. The xenon ion engines have a maximum thrust at 2.6 kW input power of 92 mN and a specific impulse of 3200 to 1900 s. The 30-cm diameter thrusters are two-axis gimbal mounted at the base of the spacecraft. The xenon tank held 425 kg of propellant at launch.

power requirements:
solar-electric-hybrid-6.png?auto=format%2Ccompress&ch=Width%2CDPR&fit=max&h=700&q=60&w=616&s=ef046c86f5947fc41b3bb9f9994f6e53

Void · 2018-02-11 13:00:25

Spacenut said:

Viod, the current ability of ION drive is why that men should not be considered. The Hall thruster is currently being used on a number of unmanned spacecraft, such as NASA’s Deep Space 1 and Dawn, they use electrically charged atoms of cesium or xenon for thrust instead of burning chemicals. The SEPs suffer from extremely low thrust – about the same as the weight of a coin resting on a table. In space, this is enough to move a vehicle at incredible speeds, but it also takes a very long time. Just spiraling out of Earth orbit can takes weeks or even months.

I am guessing it would also be bad to hang out in the Earth's radiation belts for a long time.

But this is a hybrid method which has some validity from the reference materials I found and presented.

I repeat:
https://newatlas.com/hybrid-solar-elect … asa/24791/
Quote:

NASA examines hybrid solar-electric propulsion for manned space missions

Strange and his team believe that the answer lies in combining these methods into a much more efficient and flexible system. The basic plan is to use heavy lifting rockets like NASA’s Space Launch System to boost components for a ship into low-Earth orbit. Once assembled and fueled, the SEP system would slowly push the unmanned vehicle into an elliptical high-Earth orbit. Once there, the crew would rendezvous using chemical rockets, which would also be used to push the vehicle out of orbit. After that, the SEP would propel the ship to its destination.

I don't like you "Oh not everything is perfect yet, so just drop it attitude". It is well to challenge me to find a solution for certain problems, but I don't like the "Lets give up attitude."

Just picking the reference materials apart, could we agree than a modification of that plan I will describe could have potential?
1) Ion propulsion puts a payload into high Earth elliptical orbit. Now we are done with Ion drive.
2) A crewed chemical ship goes to the high elliptical orbit payload.
3) They tell the Ion drive to go home.
4) They head to Mars on chemicals only.

This hybrid method avoids all of your time exposure concerns, due to the slow acceleration of Ion drives.

I am going to find it very hard to accept if you deny that.

So, until Ion drives "Grow Up" or are replaced with something else, that is all the part that they can have, other than positioning supplies at Mars prior to a crewed mission.

Surely this is reasonable.

......

Now also a problem with what happens at this site, is a lack of forward thinking. It is quite possible that Ion drives will grow up.
The solar panels become more productive with less mass, or nuclear power.

If SpaceX were to establish a Mars base say in 7 years, which I think is way sooner than it will happen, then lets suppose we might want an efficient people transport system in 10 years. That's 10 years of Ion drives growing up, becoming more capable. And that is an assumption, I could be wrong about it but so what! This is speculative thinking.

I think I have been quite fair in drawing attention to the deficiencies of the Neumann drive. But it is a new born. If there are ways to make it better, there are good chances it will occur within the next 10 years. Otherwise, I guess it will be the Xenon gas method which may also improve (Lighter and better solar cells, maybe the engine itself).

......

So, I am going to go ahead with speculation on a sun orbiting "Variable" cycling spaceship. I really am not sure I want this but I want to consider it.

In this case I am supposing that it will go into orbit of Mars periodically but not into orbit of Earth. It will pass by Earth periodically allowing a crewed mission to intercept it. I am getting to be like a lot of people here in not liking the idea of a deep space intercept. Particularly if the options of recovery from a missed intercept are weak, and the reliability of the hardware as starting from the Earth/Moon system is not sufficient.

The device can be resupplied at Mars since it will periodically go into Mars orbit (I hope the highest possible Mars orbit).
It could also be resupplied by robotic Ion rocket from the Earth/Moon.
As for its nature, I want it to be a synthetic gravity device with both propulsive options. Ion and Chemical (Unless Nuclear comes along).
If possible also add on Earth pass gravity assist.
Also add in an extra helping of radiation shielding, since the thing will not be going in and out of Earth orbit, and if you can manage an Earth pass gravity assist that could work out well.

With some synthetic gravity and extra radiation shielding, some of the problems of a longer duration mission are perhaps mitigated.
With an Earth pass gravity assist, ion propulsion, chemical propulsion options then a ballistic capture to higher Martian orbit might be a suitable option.

It is the option I want, since a synthetic gravity device is not something that you want to try to aerocapture into Martian orbit. (I think )

What are the dangers of this?
1) The deep space intercept (Near Earth) while the device is doing an Earth pass gravity assist boost is dangerous.
However as the mission is just starting, the maintenance on the interceptor should have been high quality, and recent.
2) You have to refurbish the device in Mars orbit, where infrastructure may be rather weak for a long time.
However, robotic Ion drives should have been able to deliver replacement materials/parts to that Martian orbit efficiently.

How comfortable am I with this idea? Well time will tell. At least 10 years.

Is it the right way to go for a people transporter? Well, in about 10 years we will see what else has emerged.

But in the meantime there is always the concept of BFR or some government(s) program.

I would expect that some derivative of BFR would be used to transport people from the synthetic gravity device to the Martian surface.

Done enough.

I am going to be out of touch for a while.

Last edited by Void (2018-02-11 13:43:28)

GW Johnson · 2018-02-11 16:23:36

I can't say I understand what is being debated here.

I can say I recommended against ion-propelled spiral-out trajectories through the van Allen belts with men. That's the way to get a fatal dose of radiation, plus the trip time is longer than by impulsive Hohmann transfer by multiple months.

What I recommended was sending ahead by ion propulsion in a spiral-out/spiral-in trajectory the unmanned assets that would not get radiation poisoning or care about a long flight time.

That kind of trajectory, once spiraled-out to interplanetary, is sped up by firing the ion propulsion continuously to midpoint, then reversing to decelerate continuously until the spiral-in capture at Mars. Done that way, Mars was a 13 month trip, versus a nominal 8.5 months by min energy impulsive Hohmann transfer.

GW

Last edited by GW Johnson (2018-02-11 16:24:07)

SpaceNut · 2018-02-11 16:35:15

You guessed correct to not linger long in the Earth's radiation belts.

LOW ENERGY TRANSFER TO THE MOON

Mars is a distance to time equation for mans' health concerns with the rocket being the mass to acceleration via power for proplellant use with ION drive and with propellant being a chemical mass for speed to mars.

Earth to Mars Ballistic Mission Opportunities, 1990-2005 Interplanetary Mission Design Handbook, Volume I, Part 2

The Analysis of Mars Atmospheric Entry

New route to Mars could make manned mission much cheaper and easier
https://www.quora.com/Is-it-true-that-t … is-that-so
work by Topputo and Belbruno: Earth--Mars Transfers with Ballistic Capture

Mathematicians have plotted out new route that solves two of the biggest problems with the Mars mission — but it takes longer. The two big problems that have held humans back from getting there — the cost of the journey and the fact that it can only done every two years.

The current route requires a huge amount of fuel to be used. It also can only happen once every 26 months, when the planets line up in the right way.

It requires lobbing the ship into an orbit like that of Mars so that it flies ahead of the planet, called ballistic capture. That is instead of the Hohmann transfer that’s currently used, where the spaceship is aimed at a certain place in the Mars orbit and meets it there.

The two techniques costs the same at launch and while it cruises. But the expensive burn of fuel to slow down and aim when the ship reaches Mars is reduced. But the new route takes a few months longer than the normal 6 months.

The 25 per cent less fuel used will reduce costs, and will make the ship lighter and therefore even cheaper to launch when using gravity capture.

Void · 2018-02-11 19:43:13

Well, I thank you for your patience Spacenut.

I can see that there are real rocket people working on stuff. I will stand down, and be satisfied that you and I approached some kind of an approximate mutuality.

Void · 2018-02-12 08:26:24

GW said:

I can't say I understand what is being debated here.
I can say I recommended against ion-propelled spiral-out trajectories through the van Allen belts with men. That's the way to get a fatal dose of radiation, plus the trip time is longer than by impulsive Hohmann transfer by multiple months.
What I recommended was sending ahead by ion propulsion in a spiral-out/spiral-in trajectory the unmanned assets that would not get radiation poisoning or care about a long flight time.
That kind of trajectory, once spiraled-out to interplanetary, is sped up by firing the ion propulsion continuously to midpoint, then reversing to decelerate continuously until the spiral-in capture at Mars. Done that way, Mars was a 13 month trip, versus a nominal 8.5 months by min energy impulsive Hohmann transfer.
GW

The board was quiet, so I took the opportunity to make some speculative inquiry, but made a mess of it. Spacenut got high blood pressure over it possibly. However I am trying to salvage what might have some worth.

I missed your post earlier. I recalled what you said. I at least have that kind of learning ability. So I did stay away from a crewed spiral out through the Van Allen Belt.

Last edited by Void (2018-02-12 08:32:21)

Void · 2018-02-12 08:34:09

I want to explore a method to leverage BFR (The plans presented by SpaceX itself).

So they say they are going to have a crew BFR and a Fueling BFR.

Using those components, and an Ion propulsion system, it seems to me that a potential exists to refuel the crewed BFR in high Earth orbit. I would imagine that could give it more capability.

However to not loose the value of super chilled propellants, a method would be needed to keep them super chilled during a ion propelled transit to high Earth orbit. (I almost missed that point).

It also occurs to me that the Lunar Gateway is not that wrong of an idea.

Done.

Last edited by Void (2018-02-12 08:51:08)

Void · 2018-02-12 13:02:01

I am going to take a shot at redemption.

I will always regret the title of this topic, and the introduction, but I think it lead to a better understanding (By me) and perhaps a better method.

A very modified method, that you might not even think is derived from the original, but it is.
......

This is not that final method, but lead to it:
-Send a chemical booster to a circular sun orbit, about 1/2 of the way to Mars (1/2 the way as measured by thrust force).
-The booster would be placed there by an ion rocket.
-Move a crewed vessel quickly through the Van Allen belts to a depot in the Earth Moon system, perhaps similar to the lunar gateway.

There, it is joined to a Solar Powered Ion rocket.

So they set off on a mission to join the booster in sun orbit. Perhaps at that location the suns intensity is about 75% of Earths, so solar panels are getting to be less useful.

Be patient Spacenut, this is not the final edition. If you could intercept a chemical booster in a relatively circular sun orbit, then do so, and then drop the ion drive and boost with the chemical booster the rest of the way to Mars. Intercept Mars by the method of practicality or your liking.

......

My current plan as of today:
?Why have a deep space intercept?
Just boost with the chemical booster and the crew vessel, using a bigger Ion rocket.
Therefore you did make a propellant depot, but you are traveling with it. The Ion rocket is taking you by spiral course as far as you plan it to. I stated 1/2 of the effort, but that is an arbitrary decision. It could be 30% Ion/70% Chemical, or vice versa. Too early to tell what would make the most sense if this makes sense at all.

So this is a "Staged" interplanetary mission. The Crew section, and the 1st and 2nd stage are joined in high Earth/Moon orbit, and presumably toped off for propellant, and whatever cargo is desired.

The 1st stage is the Ion rocket, and the 2nd stage is the Chemical rocket. It is a hybrid system.

The 1st stage is most efficient I think during the 1st part of the journey, and the 2nd stage can be used to shorten the time duration of the flight after that.

......

So what do you do with the 1st stage (Ion Rocket) when you are done with it?
Option #1: Discard it.
Option #2: It has enough fuel to either fly itself to Mars where there is an orbital depot to refuel it, or back to Earth.
Option #3: A second Ion rocket works with it to do an intercept and either tows it back to some location, or refuels it. (I believe you won't like that idea).

......

As for the chemical 2nd stage booster, I favor a hybrid, but I am not rigid about that. Solid rockets go until they can't go anymore. For Oxygen/Methane, you are likely to have expansion and boil-off.

But with a Hybrid, if you have expansion from very chilled Oxygen, you might do a few burns of the Hybrid to utilize that resource. If you got to boil-off, then it might be at a rate that the crew could breath it, so it would not be wasted.

I hope that this is less annoying to Spacenut and G.W. than my previous activities.

Done.

Last edited by Void (2018-02-12 13:26:07)

Void · 2018-02-12 13:40:11

I do have a need. Perhaps Spacenut, O.F., or G.W. will be kind to help me understand.

If there were a planet in between the Earth and Mars, should I not expect that it could be intercepted by a Ion rocket on a spiral path around the sun?

And if that were true, could you not place a depot in that location instead of a planet, and then intercept it with spiral propulsion?

I know that Mars can be intercepted, and it's orbit is a little bit circular and a little bit elliptical.

Not saying that it is the right and sensible thing to do, but if there was a chemical rocket that with a tiny engine could spiral out, could it not act like a Ion rocket, and spiral out to Mars, or to the planet between Earth and Mars, or to a fuel depot?

Actually I don't care much anymore, except that I want to know what is wrong with my thinking. A sanity check.

I like the 2 stage hybrid now instead of depots between Earth and Mars.

Void · 2018-02-12 13:50:55

Relating to post #21 of this topic, is it possible that by starting with a spiral Ion rocket as 1st stage, and chemical rocket as 2nd stage, we can modify the rigid mandate that flights between Earth and Mars can only happen every 26 months?

That is if you really want to do a Hohmann transfer and aeroburn to arrive at Mars.

We already know that Ballistic transfer offers a more flexible option, but at some penalty of flight time.

Last edited by Void (2018-02-12 13:51:31)

SpaceNut · 2018-09-23 09:33:29

yet another depot topic that seems to have drifted as well

New Mars Forums

Announcement

#1 2018-02-09 19:45:20

People transport by leapfrog depots, a faster spiral orbit I hope.

#2 2018-02-09 20:08:41

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#3 2018-02-09 20:10:52

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#4 2018-02-10 18:03:07

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#5 2018-02-10 18:08:08

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#6 2018-02-10 19:35:51

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#7 2018-02-10 20:02:12

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#8 2018-02-11 03:29:50

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#9 2018-02-11 08:14:19

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#10 2018-02-11 08:48:32

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#11 2018-02-11 09:47:49

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#12 2018-02-11 09:52:46

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#13 2018-02-11 09:55:00

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#14 2018-02-11 12:16:30

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#15 2018-02-11 13:00:25

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#16 2018-02-11 16:23:36

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#17 2018-02-11 16:35:15

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#18 2018-02-11 19:43:13

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#19 2018-02-12 08:26:24

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#20 2018-02-12 08:34:09

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#21 2018-02-12 13:02:01

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#22 2018-02-12 13:40:11

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#23 2018-02-12 13:50:55

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

#24 2018-09-23 09:33:29

Re: People transport by leapfrog depots, a faster spiral orbit I hope.

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