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#1 2020-04-16 09:11:52

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,591

Comet Harvesting: Water for Mars

In the absence of SpaceNut, I cannot ask for guidance about where to put this item.

This new topic under Terraformation is offered for those who might be interested in helping to figure out how to harvest water from comets that pass by Mars.

To start things out, here is a quote from a NASA observation:

Explanation: Cruising through the inner solar system, Comet ATLAS C2019/Y4 has apparently fragmented. Multiple separate condensations within its diffuse coma are visible in this telescopic close-up from April 12, composed of frames tracking the comet's motion against trailing background stars. Discovered at the end of December 2019, this comet ATLAS showed a remarkably rapid increase in brightness in late March. Northern hemisphere comet watchers held out hope that it would become a bright nake-eye comet as it came closer to Earth in late April and May. But fragmenting ATLAS is slowly fading in northern skies. The breakup of comets is not uncommon though. This comet ATLAS is in an orbit similar to the Great Comet of 1844 (C/1844 Y1) and both may be fragments of a single larger comet.

What I have in mind is finding people who have the ability and the motivation to find comets that are passing within harvesting distance of Mars, and inviting them to post tips here in the NewMars forum, in addition to other locations where the subject might be of interest.

It is certainly reasonable to suppose that an "ice" truck passing through the neighborhood would be of interest to future Mars settlers, and it ought to be of interest to those who are planning (or thinking about planning) expeditions to Mars.

(th)

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#2 2020-04-16 09:15:08

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,591

Re: Comet Harvesting: Water for Mars

A Google search: how to find comets that pass near mars

gave this result (selected from a larger list):

Comets: Siding Spring (C/2013 A1) - NASA's Mars Explorationmars.nasa.gov › comets › sidingspring
Mars Spacecraft Reveal Comet Flyby Effects on Martian Atmosphere ... Close Encounters: Comet Siding Spring Seen Next to Mars ... Time for Mars to Pass ... Mars Reconnaissance Orbiter (MRO) CRISM/HiRISE stellar scan to check boresite.

Comet Will Buzz Mars Sunday: How to See It in Telescopes ...www.space.com › 27444-comet-siding-spring-mars-skywatching
Oct 15, 2014 - Comet Will Buzz Mars Sunday: How to See It in Telescopes ... It will pass closest to the sun (called perihelion) on Oct. 25 at a distance of 130 ...

Edit #1: There are a number of detailed reports about Comet Siding Spring and its close approach to Mars.

Here is an example: https://skyandtelescope.org/astronomy-n … -10162014/

The article at the link above reports on planning done by NASA and other space agencies to maneuver their orbiting equipment to be on the far side of the planet when the comet passed by.  Distance of passage was given as about 85,000 miles.

(th)

Last edited by tahanson43206 (2020-04-17 20:27:31)

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#3 2020-04-16 18:31:29

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,802

Re: Comet Harvesting: Water for Mars

What would be the most energy-efficient way to deflect the course of a comet? Do you fly into it? Put a deflection shield up against its tail?


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#4 2020-04-16 19:54:35

kbd512
Administrator
Registered: 2015-01-02
Posts: 3,455

Re: Comet Harvesting: Water for Mars

Louis,

You could differentially shield part of its surface from sunlight and the off-gassing would take care of the rest, but you'd also need a very detailed model of the body to do that.

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#5 2020-04-17 04:19:45

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,591

Re: Comet Harvesting: Water for Mars

For Louis and kbd512 ...

Thank you for adding to this topic!

The shield would seem likely to have its greatest effect if fitted before the circuit around the Sun.

For all ... please add a post to this topic if/when you see announcement of discovery of a comet that has a trajectory that brings it anywhere near Mars, as was apparently the case in 2014.

The shield deflection method would seem likely to have the greatest benefit if applied to a comet that was expected to pass close to Mars on the outbound leg.

For the inbound leg, it might be possible to collect some ice in one of Calliban's asteroid bags.

(th)

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#6 2020-04-17 05:50:53

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,802

Re: Comet Harvesting: Water for Mars

Thanks kbd - interesting! So ju-jistu style, you'd be using the energy from the Sun, differentially applied by means of a shield, to deflect it from its course, rather than using energy you apply yourself. A very clever approach.

Of course, whether we really need more water on Mars, is perhaps an open question. It could accelerate global warming possibly though on Earth scientists seem to disagree about how much water vapour traps the sun's energy or deflects it (through the albedo effect of cloud cover). On the other hand why wouldn't we be happy with some shallow oceans on Mars. Atmospheric extraction, ice mining and 90% water recycling could probably meet the water  needs of a few hundred million people on Mars.



kbd512 wrote:

Louis,

You could differentially shield part of its surface from sunlight and the off-gassing would take care of the rest, but you'd also need a very detailed model of the body to do that.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#7 2020-04-17 14:51:08

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,591

Re: Comet Harvesting: Water for Mars

For Louis re #6

As a student of economics, your vision of potential markets on Mars, or those which might be served by Mars residents, is well documented in the NewMars database.

I was surprised, therefore, to see your momentary hesitation to recognize the market opportunity for an enterprising comet harvester.  It isn't a question of water being available on Mars, as you have correctly pointed out.  It ** is ** a question of how a clever entrepreneur prices deliverables to acquire and maintain a sustainable share of the market.

Some will surely make the investments needed to provide a reliable supply of fresh, clean, potable water from the resources available on Mars.  The competition I am seeing will come from those who acquire rights to off-planet resources, and provide fresh, clean, potable water to Mars customers at prices that are just a tiny bit lower than are possible for the planet bound supplier.

For Phobos, which will (according to some forecasts) become a major shipping hub for Mars, an off-world supplier will be much appreciated, and (i suspect) the competition there will be between off-world suppliers, and NOT from planet bound suppliers.

(th)

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#8 2020-04-18 17:02:19

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,802

Re: Comet Harvesting: Water for Mars

Yes, I can see much more of an argument for water to Phobos. You might even have a rocket fuel production facility there. 

tahanson43206 wrote:

For Louis re #6

As a student of economics, your vision of potential markets on Mars, or those which might be served by Mars residents, is well documented in the NewMars database.

I was surprised, therefore, to see your momentary hesitation to recognize the market opportunity for an enterprising comet harvester.  It isn't a question of water being available on Mars, as you have correctly pointed out.  It ** is ** a question of how a clever entrepreneur prices deliverables to acquire and maintain a sustainable share of the market.

Some will surely make the investments needed to provide a reliable supply of fresh, clean, potable water from the resources available on Mars.  The competition I am seeing will come from those who acquire rights to off-planet resources, and provide fresh, clean, potable water to Mars customers at prices that are just a tiny bit lower than are possible for the planet bound supplier.

For Phobos, which will (according to some forecasts) become a major shipping hub for Mars, an off-world supplier will be much appreciated, and (i suspect) the competition there will be between off-world suppliers, and NOT from planet bound suppliers.

(th)


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#9 2020-04-18 19:14:54

Void
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Registered: 2011-12-29
Posts: 3,194

Re: Comet Harvesting: Water for Mars

I would like to suggest that there may be water production on the moons of Mars.

For our Moon, Hydroxyl seems to move about.  And apparently some water is produced.  This requires the solar wind to push Hydrogen/Protons into the lunar soil.  However that is not enough.  It is apparently required for small impactors to contribute the energy to produce water from the Hydrogen/Protons, and the Oxygen in the lunar soil.

Mercury may be hot enough in places just from the sunlight.

So, the moons of Mars seem to be rubble piles and are very porous.  Inside, I would expect them to be relatively cold.  So at the very least their may be hydrated minerals inside of them.  Just my guess.

Comets?  Ya, OK.  Down the road.


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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#10 2020-04-19 06:09:47

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,591

Re: Comet Harvesting: Water for Mars

For Void re #9

Thank you for your interest (and indirect support) of the Comet Harvesting topic!

It would seem likely your prediction will come to pass.  Each entrepreneur looking at prospects for a successful business in this specialty will surely consider the advantages and drawbacks of each approach to obtaining pure, fresh, potable water for exchange with others for valuable commodities.

It is worth noting that the water collected from comets or other passing repositories of material will most definitely need to be "processed" before it can be offered for sale or trade.  The question for the entrepreneur to try to answer before making an investment in any option is which is likely to yield the greatest return for whatever investment is made.

A factor for any business planner is certainty.  It is reasonable to try to increase confidence levels wherever possible, in taking on an inherently risky venture. The presence of abundant water (ice) can be confirmed remotely, so the risks of trying to dock with a comet will be rewarded with a payload of material suitable for (relatively inexpensive) processing at whatever processing location is chosen.

(th)

Last edited by tahanson43206 (2020-04-19 06:10:40)

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#11 2020-04-19 14:43:07

Void
Member
Registered: 2011-12-29
Posts: 3,194

Re: Comet Harvesting: Water for Mars

(th)  This is a bit (quite a bit) off topic.  But I add it because I do think there eventually could be the potential to push ships to intercept comets, and indeed, perhaps to alter the course of comets.  Maybe even light sails that are sent to the comet by laser beam to impact it and alter it's course by that means. Impacting Mars with such might achieve what you want.  Very likely with catastrophic results.  However, using Mars or Venus as a punching bag, may not be what we want.

Else, I guess you just have to send ships to it to emplace the rigging others have previously suggested.  If you could get comets into the trojan asteroid belt, they may remain stable for some time as far as evaporation.  Then you might mine them.  If you could get a gas giant planet to assist in the relocation by gravity, that seems fun.  However we really should install human populations around the solar system before we would risk the extinction of the human race.

https://soundcloud.com/isaac-arthur-148 … r-highways

Last edited by Void (2020-04-19 14:49:47)


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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#12 2020-04-19 16:30:15

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,591

Re: Comet Harvesting: Water for Mars

For Void re #11

So here is the initial topic specification:

This new topic under Terraformation is offered for those who might be interested in helping to figure out how to harvest water from comets that pass by Mars.

Your contribution is on topic, in the sense that water would certainly be harvested if an entire comet is directed on a collision course with a celestial object.  However, I agree that it ** is ** very different in scope from the initial postings.

It seems to me quite reasonable to imagine a determined crew of engineers putting together a water harvesting expedition, to intercept a comet similar to the one that passed Mars is 2014.  Whatever mass can be liberated from the moving comet can be decelerated over time and through a series of clever maneuvers, to deliver a cargo to a location where it can be harvested.

A time scale of 10 Earth years from today seems reasonable to me, for a successful execution of such an expedition, if a person of the caliber of Elon Musk or perhaps even Jeff Bezos were to decide it was worth taking the risk.

On the nation state side of the ledger, I can easily imagine Vladimir Putin deciding harvesting a comet is worth his consideration, if doing so would place Russia in an advantageous position with respect to whatever space development goals they may have in mind.

Thank you again for adding an interesting (and expansive) perspective to the topic.

(th)

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#13 2020-04-21 04:12:41

Spaniard
Member
From: Spain
Registered: 2008-04-18
Posts: 68

Re: Comet Harvesting: Water for Mars

I think that it would be easier to launch volatile "pellets" from a giant planet moon.
Ganymede for example.

It has no atmosphere, so they can put the ice on route easily with a cannon or a enormous rail-gun. With some small rocket "attached" (could use gravity drag, so no need to this attach to be spend in the collision), a multi ton rock with minor corrections could be easily targeted to Mars.

Launch as much as need... There is more than enough volatiles on that moons.

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#14 2020-04-21 07:18:24

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,591

Re: Comet Harvesting: Water for Mars

For Spaniard re #13

Thank you for this interesting addition to the scope of the topic.  In pursuing your idea, I found a web site I'd not seen before.  The lead author of the site appears to have been making a significant effort to collect useful information about Delta-v between various solar system objects (and a great deal more).

http://www.projectrho.com/public_html/r … ntable.php

Ganymede shows up in a table called "Delta-v and Travel Time for ROUND Trips To or From Terra's Surface"

The author introduces a term I have not seen before, for ion drive (type) engines: "Brachistochrone"

About 1/3rd of the way down the page, the author shows a table that is more helpful for the Ganymede proposal.

This table is entitied "Solar system", and it includes a set of planets and objects along X and Y axis.  Jupiter (with respect to Mars) shows 25,265 Delta-v and an estimated flight time of 2 years and 3 months (rounded up).    The author reminds the reader that the software used is not "NASA grade".

Never-the-less, if you are serious about planning to harvest useful materials from Ganymede, I'd like to encourage you to create a topic in the Interplanetary Transportation Index topic, and begin to develop the details of how that would be done.

You will (I hope) be thinking about creating a business with Ganymede and Mars as the first leg of a trade pattern. 

You will have an opportunity to report (in the context of the NewMars forum) your discoveries about the various obstacles to be overcome in setting up your business.

I'd like this topic to focus closely to the idea of working with comets.

Unlike your sensible and practical idea to harvest materials from Ganymede, a comet harvest strategy is dependent upon random events offered by the Universe.  The potential advantage of a comet harvesting strategy is that the source of materials can be expected to come close to the intended end user upon occasion.  A proof of concept is the 2014 fly-by of a decent sized comet by Mars.

Thank you again for your contribution to this topic!

Best wishes for success with your new Ganymede topic!

It should be fun for you to develop, and you can be assured of at least ((one)) interested follower.

(th)

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#15 2020-04-30 10:31:51

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,591

Re: Comet Harvesting: Water for Mars

A "new-old" comet is approaching the Earth ... closest approach to Earth is estimated at (about) 50 million miles (80467200 km) in the middle of May (on Earth).

https://www.space.com/bright-comet-atla … -2020.html

This article, by By Joe Rao 24 days ago, includes an ephemeris for those who might be able to plan ahead for a possible viewing.

The comet is thought to have been around the Sun before (old) but (perhaps) consist of a part of the first trip package, and therefore "new" in terms of behavior with respect to the exposure of volatiles.

While we are some years away from being able to mount expeditions to harvest such travelling repositories of potential wealth, we can certainly foresee that at some point at least one expedition will set out to intercept the comet and redirect the most valuable materials for use where needed.

That time won't be too different from the present, when expeditions still head out into the (now well-charted) oceans to collect fish for sale on shore.

(th)

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#16 2020-05-27 11:47:04

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,591

Re: Comet Harvesting: Water for Mars

The article at the link below reports on results of careful study of an object in the Trojans cluster leading Jupiter.

The object is releasing material like a comet, but it appears to have been captured.

This suggests it still may be around when NASA's planned probe gets there:

https://gizmodo.com/freaky-active-objec … 1843587415

Excitingly, NASA will be launching a probe to visit the Trojan asteroids. Called Lucy, the spacecraft will investigate a half-dozen Trojans between 2027 and 2033. This mission will shed new light on these mysterious objects, including their chemical composition and how they found themselves within Jupiter’s orbital path.

I'm not sure about the energy economics, but at least there appears to be a prospect that substantial amounts of water may be available in Jupiter's orbit.

This topic was created to think about harvesting water and other useful materials from comets that fly close to Mars, but it might be easier to go collect materials from a sitting duck.

(th)

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