Kevlar Tether for Phobos

In 2020, a member of the NewMars forum with the ID of “Void” initiated a discussion that has been continuing and evolving ever since. The post that started the sequence contained a simple speculation that it might be possible to deliver gas to the surface of Mars in a “bubble”.

The question led to a mathematical analysis by a member with a PhD in Aerospace Engineering, and the clear answer appears to be a definite NO, if the “bubble” is dropped from the altitude of Phobos with zero horizontal velocity with respect to the the surface of Mars.

The pull of Mars’ gravity, though less than that of Earth (38%) will ** still ** accelerate the bubble (ie, balloon) to a velocity significant enough to insure the object impacts on the surface, instead of floating as might have naively been imagined if the contents is Hydrogen.

However, taking the judgement of the PhD (GW Johnson) in stride, other members began considering the possibility of releasing the bubble at an altitude closer to the surface. That led to renewed discussion of tethers. It turns out that tethers have received some serious attention during the 20 years the NewMars forum has been available as a public service of the Mars Society. In particular, quotations from a web site/ blog by “Hop” show illustrations of various tethers that might be constructed, including one for Phobos.

The inspiration of the vision published by Hop led to work on a concept that might be implemented with Phobos as the anchor. The distance from Phobos to just above the surface of Mars is (about) 3700 miles (5955 km).

Since the Hop blog post suggests Kevlar as a material that might be strong enough for this application, a design is in development to make links of a chain of Kevlar thread. Kevlar thread is offered commercially on Earth in various grades and lengths. A #92 thread is 290 micrometers in diameter, and it can hold 25 pounds or just over 13 kilograms. This information can be (and is being) extended to the design of a chain of Kevlar thread links that would extend 3700 miles toward the surface of Mars.

It appears that a bubble/balloon released from the lowest rung of a Kevlar chain from Phobos would have a modest horizontal velocity with respect to the surface of Mars, and since vertical velocity would be zero at the time of release, a package would have a reasonable chance of survival. In particular, the possibility that a package could be buoyant (ie, filled with Hydrogen) is greater than zero. Testing at Mars, or calculations using CFD (Computation Fluid Dynamics) software may show one way or the other.

In any case, to see images of the CushionGuide intended to bear the compression load between links of the Phobos Tether, readers are welcome to visit the NewMars forum at:

http://newmars.com/forums/viewtopic.php?pid=168624#p168624

(th)

Cocoon for Apophis

Cocoon for Apophis from NewMars forums

A discussion is underway on the NewMars.com/forums web site, regarding a concept shown by nature, for capturing an asteroid. In nature, creatures (eg. caterpillars) wrap themselves in a cocoon (eg. silk thread) to prepare for metamorphosis. Asteroids such as Apophis are thought to be loose piles or collections of rubble held together by very small gravitational forces.

Such objects cannot be moved through application of a force, such as that produced by a chemical rocket. Wrapping such an object in a cocoon of basalt thread (as an example) would appear to offer a solution to the problem of giving the object a structure to facilitate movement to a harvesting location.

Here is a recent post by the forum administrator, inviting composition of an article about this topic, for possible display on the main page of the Mars Society web site. Luf.org readers are invited to think about the problem, and offer their thoughts about how best to proceed:

tahanson43206 wrote:

For SpaceNut re #

First, thanks for the reminder of the many contributions of JoshNH4H during his tenure as a moderator and member of the forum.

And thanks for the interesting teaser of an opportunity for the Asteroid Cocoon contingent. 

From my perspective, some work is still needed to reduce uncertainty in numerous areas. 

I’m not sure how many bullet points I’m going to come up with, but I’ll start and see how far it goes …

1) Is the surface of Apophis suitable for manufacture into thread?

2) Can equipment fabricated for manufacture of basalt thread here on Earth be adapted to deep space and whatever material Apophis offers?

3) Is there an optimum strategy for wrapping the cocoon.  Calliban’s long arm from a pole is what Nature offers as a model, but that would be slowest.

4) Would SpaceNut’s idea of tossed toilet paper rolls (as a metaphor of course) work at all, and if so, how would it be designed for the free space situation?

5) What amount of wrapping material is needed?  Nature provides a model of multiple layers of thread. Can we get by with less?

6) Where would the world want the asteroid to be delivered?  I say the world, because there is ** no ** doubt the world has an interest in the project.

7) Speaking of the world … what international agreements are needed to avoid unhappy and worried people, let alone nations?

Enough for now …

(th)

Maybe its time for a consolidated write up for this topic to be posted on the home page..targetting the above bullets to finish out what we might be missing…

Buy Materion (MTRN)

Today’s recommendation is a little different that past ones. Previous investment ideas have had a “green” tilt. Today’s has a “tech/space” tilt. Materion is a mining company (a good one!) and mining is hard to do in an environmentally friendly manner. It is a necessary evil for a technologically advanced society. Eventually, this dirty industry should move off planet but for now we have to make do. Fortunately, the material this mine produces is particularly useful for aerospace applications and advances the cause.

Continue reading “Buy Materion (MTRN)”

Climate Change Fuel Options

kbd512 is a member of the NewMars forum who frequently contributes long posts which are rich with detail, and show careful thought in preparation. In the post below, kbd512 looks at a variety of options for human beings to address climate change, and offers recommendations based upon various factors.

Readers of luf.org should be aware that kbd512 posts on a variety of topics, some of which might be offensive. The post below confines itself to physics, economics and technical fields, so should be acceptable in this setting.

Continue reading “Climate Change Fuel Options”

Economics of Mars

newmars.com/forums

Index>> Martian Politics and Economy >> Economics of Mars

Louis: Member from UK

Registered 2008-03-04: Posts: 5,198

I’ve just been reading a book on economic theory called 30-second economics (it’s actually a more in-depth study then that title might suggest). I thought it might be interesting to work through the theories and ask how they relate to a future human society on Mars since I don’t think anyone here or elsewhere has ever attempted to do that…

Classical economic theory This theory has evolved out of Adam Smith’s original writings which indicated that the rapidly adjusting market ensures equilibrium, stability and prosperity.

My comment: The free market will be largely absent from Mars for at least a couple of decades following the arrival of humans in my view. This partly reflects technology (the need to ensure that life support technology is in place) and partly the way missions will be structured (under the control of a centralised planning team). There will be a market between Mars and Earth e.g. over science experiments, where I anticipate demand will exceed supply.

Marxism Marx  predicted the inevitable evolution of a classless society based on the principle of “from each according to their ability and to each according to the need”.

My comment:   In a sense the early missions to Mars will probably reflect these principles. All the participants will be highly dedicated to giving their all to the project and financial motivation will not be required. Equally, they will be happy to help a fellow pioneer who may be in need – e.g. in need of medical treatment.  But Marxism is not an organising principle that works well with larger and more sophisticated societies.

Keynesian economics.  Keynes argued that the business cycle was driven by aggregate demand and suggested that government could intervene to smooth out the ups and downs of the business cycle by manipulating aggregate demand for goods and services.

My comment:    The business cycle is a reality in all markets but it is worth pointing out that we have, on Earth,  had steady growth in world GDP year by year virtually every year since World War II. This is due to technological innovation, improved transport and communications and a growing population. 

The Mars economy will be growing from a tiny colony into an economy based on substantial human populations possibly millions within 100 years. So I think we will not see major business cycle dips. There is perhaps a risk of investment “bubbles” going forward which may cause economic dislocation.

To be continued…

Last edited by louis (Today 09:46:57)

Louis added additional posts to his topic. These may be viewed at the links below:

Post #1 http://newmars.com/forums/viewtopic.php?pid=163436#p163436

Post #4 http://newmars.com/forums/viewtopic.php?pid=163447#p163447

Post #5 http://newmars.com/forums/viewtopic.php?pid=163449#p163449

Post #6 http://newmars.com/forums/viewtopic.php?pid=163456#p163456

Post #7 http://newmars.com/forums/viewtopic.php?pid=163472#p163472

The Procure Space ETF (UFO)

Today, I’m reviewing a new way to invest in the new space movement. There are three good reasons for investing in space at this time: 1) location based sharing apps are growing rapidly thanks to satellite enabled navigation 2) decreasing launch costs are creating new economically viable industries 3) with the formation of the US Space Force governments and the defense industry are poised to increase investment in space.

Continue reading “The Procure Space ETF (UFO)”

SBSP & Solar Electric Propulsion

Could we one day use the Space Solar Power to travel around the Solar System?

When Valery Danko in 2019 went to interview Professor Naoki Shinohara, during the intial contact phase, he mentioned an experiment using Microwave beam technology to fly a small drone. In other words, no energy is carried on the drone, it all comes from the microwave beam at a distance!

This example is not clearly the same as Solar sail, but the principle is the same. The drone saves vital weight carrying fuel or batteries. The energy is supplied by the sun, using another electromagnetic beam of radiation!

Continue reading “SBSP & Solar Electric Propulsion”

Mars – Will Space Solar Power be the key to its future?

The Developed Martian Colony

Mars is a very hostile place with a thin atmosphere and less solar energy than on Earth. It’s very far away from Earth – anywhere between 55 and 401 million kilometres. (34 million miles and 249 million miles). There’s no life on it as far as we currently know. Its atmosphere is so thin that it is an excellent insulator. However, it might also be so hot in the sun that living things will have problems without considerable energy use to keep cool. Artificially Intelligent (AI) robots will be critical to any development of a martian colony. Also, if we decide to nuke it before we turn up (as Elon Musk suggests) we can thicken up the atmosphere and hopefully create, albeit low gravity, conditions for growing food. To make it worthwhile, we’ll have let the robots build mars before humans arrive.

Continue reading “Mars – Will Space Solar Power be the key to its future?”