Interplanetary Superhighway used for large masses

[paulthew]

Shane Ross, a professor at Virginia Tech, proposed this concept of an interplanetary superhighway requiring very low energy in this presentation: 



If this concept proves to work well, it should follow that large masses could be sent between planets as long as they could be lifted to Lagrangian points. 

[Coastal Ron]

Shane Ross, a professor at Virginia Tech, proposed this concept of an interplanetary superhighway requiring very low energy in this presentation:

He likely wasn't proposing it, since the physics of this have been understood for quite a while.  Here is a Wikipedia entry about it that has the graphic he used in his presentation:

https://en.wikipedia.org/wiki/Interplanetary_Transport_Network

If this concept proves to work well, it should follow that large masses could be sent between planets as long as they could be lifted to Lagrangian points.

It's already been used.

[Robotbeat]

"The Interplanetary Superhighway, also known as "The Net," is a series of tubes connecting the planets together. " 

[paulthew]

I was thinking it should be used for sending heavy equipment to Mars and other places, such as mining equipment, fuel plants, building equipment, vehicles for people to use, and return vehicles.  Much larger payloads could be sent to Mars, for instance, if we only have to get them to Earth-Moon L1 and then use very little more fuel until they have to land on Mars.

[Coastal Ron]

I was thinking it should be used for sending heavy equipment to Mars and other places, such as mining equipment, fuel plants, building equipment, vehicles for people to use, and return vehicles.  Much larger payloads could be sent to Mars, for instance, if we only have to get them to Earth-Moon L1 and then use very little more fuel until they have to land on Mars.

Here on Earth the most fuel efficient means of transportation, such as ships and trains, and also our slowest ways to move cargo.  So it's really a matter of how quickly the "customer" needs their cargo at the destination.

Other factors that play into that equation are how much cargo is in the transportation network.  For instance, if you need a constant supply of food and medical equipment, as long as you can afford to a lot of cargo in transit then once you fill up the transportation network the customers at the destination will see a continuous supply.  It's very costly to fill up a transportation network though, since all the inventory is money not being put to use.

However if you have perishable items, which includes things that either have a limited lifetime or are affected by the conditions of the journey from Earth to wherever, then the slowest mode of transportation may not be the best choice.

[sanman]

If you're going to "fill up" the "pipeline", then wouldn't it be more useful to have some kind of shuttle system that transfers payload mass between planetary surface and LaGrange point? So one would be at the Earth-end of the pipeline, and the other would be at the Mars-end of the pipeline, for example.

[Coastal Ron]

If you're going to "fill up" the "pipeline", then wouldn't it be more useful to have some kind of shuttle system that transfers payload mass between planetary surface and LaGrange point? So one would be at the Earth-end of the pipeline, and the other would be at the Mars-end of the pipeline, for example.

I'm not a rocket engineer, or familiar enough with the physics of delta-v to know the best departure point from Earth, but it would seem to me that once we have a constant need for mass to be delivered beyond Earth's LEO that optimized transportation routes will be established.  So having a transport hub at a Lagrangian point will probably make sense, since the modes of transportation between Earth and an L-point will be different than the transportation used between planets.

But it will be the overall supply & demand forces that determine how quickly cargo needs to be moved between two points, and I think we'll initially see fast modes used, but as the destination areas get more established the focus will shift to lowering the sustaining costs, so more fuel efficient transportation routes will be used for bulk items.

My $0.02

[Hop_David]

Shane Ross, a professor at Virginia Tech, proposed this concept of an interplanetary superhighway...

If this concept proves to work well, it should follow that large masses could be sent between planets as long as they could be lifted to Lagrangian points.

Following WSBs from Sun earth Lagrange 2 (SEL2) to Sun Mars Lagrange 1 (SML1) would likely take thousands of years. Shane Ross acknowledges this in his comments on my blog post Potholes on the Interplanetary Super Highway.

Much ado is made of Belbruno's help to Hiten that helped get the probe to a loosely bound lunar orbit. Well, Hiten had already invested most of the 3.1 km/s needed to reach a high apogee. Farquhar devised a route from LEO to EML2 that takes about 3.4 km/s. So how much delta V did Belbruno save? around .3 km/s. It's noteworthy but definitely not the revolutionary innovation some think it is. See EML2

[Hop_David]

It's already been used.

Not for moving between planets. More like getting to sun earth L2 or L1.

The earth and moon have a healthy 3 body mass parameter. Which makes EML1 and EML2 interesting. It is also possible to travel from EML2 to SEL1 or 2 for little delta V.

But beyond earth's Hill Sphere? The WSBs emanating from SEL1 or SEL2 are not interesting. The sun/small rocky planet mass parameters are miniscule. A ballistic path from SEL2 to SML2 would take thousands of years.

[sdsds]

Existence of the ballistic (i.e. zero delta-v along the way) paths principally puts an encouraging bound on the delta-v that would be required to transfer between periodic orbits near two Lagrange points. The math is not easy, but Parker provides a fairly straight-forward presentation in "FAMILIES OF LOW-ENERGY LUNAR HALO TRANSFERS." (See the text around figure 3.)

For the two example orbits shown the text emphasizes that there are ballistic transfers, but the figure also clearly shows there are transfers which take small amounts of impulsive delta-v part way along the path. Those could have shorter transfer times.

A speculative extension of that would be the possibility of using similar methods to find continuous thrust low impulse paths that effect the same transfer in considerably less time than other low impulse approaches.
 
http://ccar.colorado.edu/nag/papers/AAS%2006-132.pdf

[Hop_David]

Existence of the ballistic (i.e. zero delta-v along the way) paths principally puts an encouraging bound on the delta-v that would be required to transfer between periodic orbits near two Lagrange points. The math is not easy, but Parker provides a fairly straight-forward presentation in "FAMILIES OF LOW-ENERGY LUNAR HALO TRANSFERS." (See the text around figure 3.)

For the two example orbits shown the text emphasizes that there are ballistic transfers, but the figure also clearly shows there are transfers which take small amounts of impulsive delta-v part way along the path. Those could have shorter transfer times.

A speculative extension of that would be the possibility of using similar methods to find continuous thrust low impulse paths that effect the same transfer in considerably less time than other low impulse approaches.
 
http://ccar.colorado.edu/nag/papers/AAS%2006-132.pdf

I believe there are heteroclinic orbits between EML1 and EML2. I know there are low delta V routes from EML2 to SEL1 or 2.

But there are no such routes between SEL2 and SML1. At least no such routes that would take less than centuries. More likely tens of millennia. These routes are not much good for departing from the earth-moon neighborhood.

Looking at Table 2 of the Miller paper you cite, I see that Miller assumes .819 km/s for insertion to lunar orbit from a Hohmann transfer. And 3.14 to depart from LEO. A total of about 3.96 km/s

Sdsds, if I recall correctly you've done your own sims of the Farquhar route. It totals about 3.4 or 3.5 km/s, substantially less than Miller's Hohmann.

Farquhar's route is basically a Hohmann. But at Hohmann apogee the spacecraft is very close to the moon. Farquhar does a .18 km/s burn near the moon that enjoys a substantial Oberth benefit. This .18 km/s suffices to achieve lunar capture with apolune near EML2. At EML2, a .15 km/s burn suffices to park at EML2.

Miller's treble clefs are basically bi-elliptic transfers. If destination orbit is more than twelve times the departure, bi-elliptic is cheaper than Hohmann. And the moon's orbit certainly is more than 12 times the radius of LEO. Then at the apogee of Millier's bi-elliptic transfer, the sun's tidal influence is strong. The sun helps raise the apogee as well as the perigee, it raises the perigee to the moon's neighborhood. From there a ballistic slide into loosely bound lunar capture is doable.

Using my shotgun orbital sim, I found a route to EML2 even cheaper than Miller's. On the way up the spacecraft gets a lunar gravity assist up to the high apogee where the sun's tidal influence raises apogee and also perigee to the lunar neighborhood. Total delta V is 3.11 km/s and trip time is 74 days.

Are these routes interesting? Sure. If a payload is tough enough to endure a few months enroute, it's a slightly cheaper way to deliver stuff to EML2. Earth shattering? No.

[spacenut]

I've always though that very large SEP propulsion for say 100 ton cargo mass would be the best solution between say L2 and Mars.  I also thought argon should be the propellant because it could be extracted from Mars atmosphere and sent up to refuel the SEP tug for return trip to L2.  L1 could be used and use earth or the moon for a slingshot around on a trip to Mars. 

From either L1 or L2, the moon could be mined, and Mars could be supplied.  Eventually rare materials mined from Mars could be sent back on a SEP tug. 

SEP tugs could also be used between LEO and L2.  Like someone said, mining and earth moving equipment, large modular habitat structures, etc. 

[Hop_David]

I've always though that very large SEP propulsion for say 100 ton cargo mass would be the best solution between say L2 and Mars.  I also thought argon should be the propellant because it could be extracted from Mars atmosphere and sent up to refuel the SEP tug for return trip to L2.  L1 could be used and use earth or the moon for a slingshot around on a trip to Mars.

I agree with most of what you say. SEP can be very durable and has great ISP. And I agree EML2 is a great place to berth an ion ship between trips. Ion ships really suck at climbing in and out of planetary gravity wells so it would be much better for them to travel between the edges of planetary wells.

I attached a graphic of interplanetary ion craft traveling between the edges of wells. It comes from my blog post Xenon. I was also an enthusiast for Martian argon as propellent mass. But Wolfe pointed out to me xenon's lower ionization energy and high molar weight. This makes xenon a much better propellent. I still have some enthusiasm for Argon, though.

Although this is interesting, it's off topic in a discussion of the Interplanetary Super Highway as proposed by Ross, Lo et al. They exploit WSBs emanating from L1 or L2 necks of various bodies that take virtually no energy. The trips with ion ships would actually take more energy. But the ion ships save on reaction mass since exhaust velocity is higher. It muddies the waters that people keep conflating trips via VASIMR or Hall Thrusters with the Interplanetary Super Highway.

[mmeijeri]

I've always though that very large SEP propulsion for say 100 ton cargo mass would be the best solution between say L2 and Mars.

Not just for large masses, also for propellant, of which you need a large amount, but which can be almost arbitrarily divided. And you could do that with almost off the shelf hardware, without needing huge tugs.

[Robotbeat]

I always like your diagrams, Hop_David.

[Hop_David]

I always like your diagrams, Hop_David.

Thanks. I'm enthusiastic about using SEP to deliver massive payloads. But not the ITN. They're different animals, not sure that's getting through. I'm attaching one of Shane Ross' comments that he left on my blog.

[SergioZ82]

That's a fascinating concept but if you guys say it takes thousand of years for an orbital transfer between Earth and Mars then it's of little or no use.
Maybe it's exploitable for relatively short distances like an Earth-Moon transfer.. at least for non perishable items as Coastal Ron says

[paulthew]

Yeah, it looks like even if it were used to lower the energy required even by a little bit, it might still not be worth the time required.  I did a spreadsheet to try to see how much it would save and it looks like it only lowers the energy required by a little bit.  Formulas are from wikipedia.  Anyway, thank you all for the discussion.

[Hop_David]

That's a fascinating concept but if you guys say it takes thousand of years for an orbital transfer between Earth and Mars then it's of little or no use.
Maybe it's exploitable for relatively short distances like an Earth-Moon transfer.. at least for non perishable items as Coastal Ron says

I't's not really distances that screw things up for using the ITN. It is the tiny earth sun 3 body mass parameter.

Compared to the sun, the small rocky planets are microscopic specks. The weak instability boundaries emanating from the earth sun L1 and L2 are not that interesting. Ditto Venus sun L1 and L2 necks. Also Mars.

It's a different story when it comes to gas giants. The sun gas giant mass parameters are large enough that the gas giants can swap comets. I haven't really looked at it but I would imagine this would also take too much time for human use. Although the comet Oterma is interesting.

The Jupiter and Galilean moons have a large enough mass parameter that a probe might go from the neighborhood of one Galilean moon to another with little propellent. I find this an interesting proposal.

Below is a list of 3 body mass parameters for various systems. The biggest by far is Pluto and Charon. I've been wanting to make a sims of the Pluto Charon neighborhood.

Pluto/Charon   1.043E-01
Earth/Moon   1.216E-02
Sun/Jupiter   9.545E-04
Sun/Saturn   2.856E-04
Saturn/Titan   2.374E-04
Jupiter/Ganymede   7.789E-05
Jupiter/Callisto   5.684E-05
Sun/Neptune   5.153E-05
Jupiter/Io   4.700E-05
Sun/Uranus   4.366E-05
Jupiter/Europa   2.526E-05
Saturn/Rhea   4.046E-06
Sun/Earth   3.039E-06
Sun/Venus   2.448E-06
Saturn/Dione   1.935E-06
Saturn/Tethys   1.091E-06
Sun/Mars   3.229E-07
Saturn/Enceladus   1.935E-07
Sun/Mercury   1.659E-07
Saturn/Mimas   7.037E-08
Mars/Phobos   1.682E-08
Sun/Pluto& Charon   7.149E-09
Mars/Deimos   2.803E-09
Sun/Ceres   4.741E-10