Asteroid/Comet Resource Utilization

[csmyth3025]

Just some rough calcs, a 4 meter diameter asteroid (100 m^3) would have a mass of 10,000 kg (pure water ice), 20,000 kg (lighter carbonaceous chondrites), to 80,000 kg (for an iron).
MW

BTW, that's 11 to 88 US tons, for the metric challenged

I'm not sure if my math is correct MW, but if I use 4/3pi(2^3) for the volume, I get 33.5 m^3. Also, using this volume, at 1 gm/cm^3 I get a mass of 33,500 kg, at 2gm/cm^3 I get 67,000 kg, and at 8 gm/cm^3 I get 268,000 kg. Is this right?

Chris

 

[MeteorWayne]

Yep, you are right. My brain auto recall of the formula forgot the "/3". Thanx!
I have no explanation for the other errors...that's what I get for posting while watching my Giants crush Da Bears :roll:

 

[MeteorWayne]

csmyth3025,

Your question inspired me to do a some checking.

There are a handful of very small asteroids in the 2-10 meter range that have been found, all by various efforts of the Catalina surveys, with the smallest (H > 30) by the Mt Lemmon site of that survey:

"Catalina Sky Surveys: The Catalina Sky Surveys (CSS) is currently the most efficient NEO survey program for finding new near-Earth objects. CSS utilizes three refurbished telescopes all using identical thinned, multichannel cryogenically cooled 4K x4K CCD cameras; 1) The original Catalina Sky Survey (CSS, MPC COD 703) using a 0.7-meter f/1.8 Schmidt telescope with a 2.9 x 2.9 degree field at the Steward Observatory Catalina Station (2510m elevation, 20 km northeast of Tucson, Arizona), 2) The Siding Spring Survey (SSS, MPC COD E12) using the Uppsala 0.5-m f/3.5 Schmidt telescope with a 2.0 x 2.0 degree field operated jointly with the Australian National University Research School for Astronomy and Astrophysics at Siding Spring Observatory, Australia (1150m elevation), and 3) the Mt. Lemmon Survey (MLS, MPC COD G96) using the 1.5-meter f/2.0 prime focus telescope with a 1.0 x 1.0 degree field at the Steward Observatory Mt. Lemmon station (2790-m elevation, 18 km north of Tucson). The 1.5-m Mt. Lemmon and 1.0-m Siding Spring telescopes are also used for astrometric follow up and physical observations of interesting NEOs. "

The smallest (highest H of +33.2) implies a rock in the 2-5 meter size range. For some reason I haven't figured out yet, they were all discovered in 2008.

MW

 

[csmyth3025]

Thanks MW. I've challenged our counterparts on the Spacesettlers forum to pick a known NEA that they feel is a good candidate for deflection from an Earth-crossing orbit to an Earth-centric orbit at an altitude of ~350 km.

There is still talk of using aerobraking in Earth's atmosphere as a means of circularizing the orbit. I cringe whenever this comes up. I don't think they realize the near imposibility of deflecting a multi-ton object of unknown composition and irregular shape into a precise keyhole window that will aerobrake without breaking up, plunging to Earth, or skipping out into a new, uncotrolled orbit.

If they come up with a specific known NEA with real orbital data, I may be searching around for where I could go to make the orbital calculations, delta-v needed for alteration of the orbit, fuel requirements, time frame to make the change, etc. One thing that worries me (among many others) is the possibility that altering an established natural orbit may cause an asteroid to run into someting else - like Mars, the Moon, or another asrteroid.

Chris

 

[orienteer]

Just for the sake of argument, let's say we put Eros at EML1. I believe that would create a Eros Earth Lagrange point that we could also use for say Vesta. Now, depending on how many asteroids we drag into earth orbit, who would be responsible for the tidal damage to the beaches around the world? I sure hope your insurance is paid up.

 

[MeteorWayne]

Just for the sake of argument, let's say we put Eros at EML1. I believe that would create a Eros Earth Lagrange point that we could also use for say Vega. Now, depending on how many asteroids we drag into earth orbit, who would be responsible for the tidal damage to the beaches around the world? I sure hope your insurance is paid up.

Vega???

 

[orienteer]

Just for the sake of argument, let's say we put Eros at EML1. I believe that would create a Eros Earth Lagrange point that we could also use for say Vega. Now, depending on how many asteroids we drag into earth orbit, who would be responsible for the tidal damage to the beaches around the world? I sure hope your insurance is paid up.

Vega???

Sorry about that, fat fingers strike again. Any way, I edited it to Vesta

 

[csmyth3025]

The general question in the spacesettlers group is whether it's practical to divert a small 4 meter diameter NEA (70 to 100 metric ton mass) to a circular Earth-centered orbit at about 450 km altitude for the purpose of mining and processing its materials in LEO for construction of space facilities. The proponents of this idea feel that this approach will be more practical than mining and processing lunar material for several reasons - not the least of which is that we dont have any facilities on the Moon and we wont have reasonable access to the Moon for a long time.

They feel that a slight "nudge" on such an asteroid will divert it to a "keyhole" pass near Earth which will put it on a resonant orbit with the Earth. They would subsequently tweak this orbit with "nudges" on subsquent passes to use aerobraking in Earth's atmosphere to circularize the orbit.

Does anyone feel that this scheme is possible in theory or, more importantly, doable in real life? My concerns are:
1) It will take more than a "nudge" to divert a NEA that has projected future close approaches to Earth that most probably are measured in (at best)10's of thousands of km and, more likely, several hundred thousand km, to a future approach that will hit a "keyhole" window measured in tens of km.
2) The time frame for such a diversion - if attempted - would be several, if not many, decades.
3) The political furor over a plan to deliberately divert an asteroid - however small - into a possible Earth impact trajectory would kill the project before it got started. The proponents argue that 4 meter meteorites enter the atmosphere about once per year without doing any harm so this objection isn't valid.
4) Trying an aerobraking maneuver on an asteriod of uncertain composition and irregular shape is not likely to result in any predictable result.

Chris

 

[rockett]

Seems like a lot of effort and expense for very little result...

 

[oldAtlas_Eguy]

The general question in the spacesettlers group is whether it's practical to divert a small 4 meter diameter NEA (70 to 100 metric ton mass) to a circular Earth-centered orbit at about 450 km altitude for the purpose of mining and processing its materials in LEO for construction of space facilities. The proponents of this idea feel that this approach will be more practical than mining and processing lunar material for several reasons - not the least of which is that we dont have any facilities on the Moon and we wont have reasonable access to the Moon for a long time.

They feel that a slight "nudge" on such an asteroid will divert it to a "keyhole" pass near Earth will put it on a resonant orbit with the Earth. They would subsequently tweak this orbit with "nudges" on subsquent passes using aerobraking in Earth's atmosphere to circularize the orbit.

Does anyone feel that this scheme is possible in theory or, more importantly, practical as a real world strategy?

Chris

It’s all a matter of economics. If the equipment used to perform this is not extremely cheap then it would need to be reusable for subsequent object retrievals. This would spread out the costs of the hardware and development over multiple missions resulting in more material for the processing plants.

If it’s not viable economically with a high return it won’t work. So if the estimates don’t show a 2 to 1 return to costs it’s not doable.

 

[EarthlingX]

www.physorg.com : Water discovered on second asteroid, may be even more common

October 7, 2010


Credit: Gabriel Pérez, Instituto de Astrofisica de Canarias, Spain

Water ice on asteroids may be more common than expected, according to a new study that will be presented today at the world's largest gathering of planetary scientists.

Two teams of researchers who made national headlines in April for showing the first evidence of water ice and organic molecules on an asteroid have now discovered that asteroid 65 Cybele contains the same material.

"This discovery suggests that this region of our solar system contains more water ice than anticipated," said University of Central Florida Professor Humberto Campins. "And it supports the theory that asteroids may have hit Earth and brought our planet its water and the building blocks for life to form and evolve here."

Campins will present the teams' findings during the 42nd-annual Division of Planetary Sciences Conference in Pasadena, Calif., which concludes Oct. 8.

Asteroid 65 Cybele is somewhat larger than asteroid 24 Themis – the subject of the teams' first paper. Cybele has a diameter of 290 km (180 miles). Themis has a diameter of 200 km (124 miles). Both are in the same region of the asteroid belt between Mars and Jupiter.

The academic article reporting this new finding has been accepted for publication in the European Journal "Astronomy and Astrophysics."

...

 

[HopDavid]

http://www.physorg.com : Water discovered on second asteroid, may be even more common

October 7, 2010


Credit: Gabriel Pérez, Instituto de Astrofisica de Canarias, Spain

Water ice on asteroids may be more common than expected, according to a new study that will be presented today at the world's largest gathering of planetary scientists.

Two teams of researchers who made national headlines in April for showing the first evidence of water ice and organic molecules on an asteroid have now discovered that asteroid 65 Cybele contains the same material.

"This discovery suggests that this region of our solar system contains more water ice than anticipated," said University of Central Florida Professor Humberto Campins. "And it supports the theory that asteroids may have hit Earth and brought our planet its water and the building blocks for life to form and evolve here."

Campins will present the teams' findings during the 42nd-annual Division of Planetary Sciences Conference in Pasadena, Calif., which concludes Oct. 8.

Asteroid 65 Cybele is somewhat larger than asteroid 24 Themis – the subject of the teams' first paper. Cybele has a diameter of 290 km (180 miles). Themis has a diameter of 200 km (124 miles). Both are in the same region of the asteroid belt between Mars and Jupiter.

The academic article reporting this new finding has been accepted for publication in the European Journal "Astronomy and Astrophysics."

...

Thanks for posting that. I will add Cybele to my list of asteroids and water links.

The "snow line" seems to be closer in than some models have predicted.

Jessica Sunshine's explanation of the lunar water cycle may be a reason. She speculates the water above the moon and mixed with it's regolith comes from solar protons (aka hydrogen ions) interacting with oxygen rich lunar minerals. The same process could make water on other airless bodies, including asteroids.

While I still feel asteroid resources will play a huge role in the settlement of the solar system, I still advocate moon first. Given our present capabilities, even near term flags and footprints asteroid missions are a stretch. Actual mining and utilization are a fantasy.

Given lunar supplied propellent depots in LEO and at EML1, asteroid utilization may become plausible.

 

[bdewoody]

I think most people don't get it. Obama proposes a mission that excites the general space crowd knowing full well it is not doable until long after he is out of office. It allows him to scrap the more immediate and doable moon base mission and spend the money saved in typical liberal democratic vote buying programs.

 

[EarthlingX]

Moon mission is neither immediately doable (dev. on Altair would start in 2025) nor close that cheap. Money saved is going to be used for deep space tech, which might be boring, because most of the people don't understand what is so fun with ISRU, closed loop environments, new propulsion technologies and so on.

Try putting down your politically coloured glasses, it doesn't hurt that much. There is also forum for politics, should you want to discuss it.

Space resource processing should be done in space, not down in the gravity well.

 

[Valcan]

Guys,

There would be no moon base for the next 10 yrs anyway even if he hadnt cancelled constellation. They have SAID they wouldnt have ares V ready till next decade probably.

 

[HopDavid]

Moon mission is neither immediately doable (dev. on Altair would start in 2025) nor close that cheap.

Neither is a flags and footprints mission to an asteroid. For flags and footprints, 2030 is an optimistic date.

If you're talking about actual use of an asteroid that is quite another story.

Given lunar and cislunar infrastructure, I'd say asteroid mining is 75 years away.

Without lunar and cislunar infrastructure, asteroid mining is 500 years away. Or maybe never.

 

[EarthlingX]

Moon base wouldn't even start in 2030, and from then it is a long way, and if not done cheap (fuel depots), never, to the Moon base.

Asteroid mission is a first step to everywhere else, from there on you just need a specialized lander for various bodies.

Asteroid utilization needs a couple of BA-330 put at one of LPs, and asteroids, or their parts tractored there robotically. Not much new tech, apart from the tractoring part.

Moon base, perhaps, if it would be done internationally, but first robots, driven from the Earth.

There is also another thread for more of this ...

 

[HopDavid]

Asteroid mission is a first step to everywhere else, from there on you just need a specialized lander for various bodies.

Flags and footprints is a first step to nowhere.

Asteroid utilization needs a couple of BA-330 put at one of LPs, and asteroids, or their parts tractored there robotically. Not much new tech, apart from the tractoring part.

Tractoring asteroids to a Lagrange point is far more difficult than you seem to think.

Mining in a weightless environment is something we have zero experience in.

 

[EarthlingX]

Asteroid mission is a first step to everywhere else, from there on you just need a specialized lander for various bodies.

Flags and footprints is a first step to nowhere.

Agreed. Moon base in 2050, if everyone keeps focus.

Asteroid utilization needs a couple of BA-330 put at one of LPs, and asteroids, or their parts tractored there robotically. Not much new tech, apart from the tractoring part.

Tractoring asteroids to a Lagrange point is far more difficult than you seem to think.

Mining in a weightless environment is something we have zero experience in.

As opposed to lunar mining which is a common knowledge, right ?

There is a lab in microgravity which can, and already does, test various needed technologies for processing resources in weightless environment.

There will be hardly any tractoring before more is known about NEOs, and this is what asteroid mission is about, among other.

 

[HopDavid]

Asteroid mission is a first step to everywhere else, from there on you just need a specialized lander for various bodies.

Flags and footprints is a first step to nowhere.

Agreed. Moon base in 2050, if everyone keeps focus.

Asteroid utilization needs a couple of BA-330 put at one of LPs, and asteroids, or their parts tractored there robotically. Not much new tech, apart from the tractoring part.

Tractoring asteroids to a Lagrange point is far more difficult than you seem to think.

Mining in a weightless environment is something we have zero experience in.

As opposed to lunar mining which is a common knowledge, right ?

Getting hydrogen and oxygen from water is fairly straight forward. The moon's 1/6 gravity would enable use of the many of the methods we're accustomed to.

There is a lab in microgravity which can, and already does, test various needed technologies for processing resources in weightless environment.

Which is far short of actual experience. Actually mining will require new tech.

There will be hardly any tractoring before more is known about NEOs, and this is what asteroid mission is about, among other.

To learn about NEOs, I'd rather invest in a fleet of prospector probes rather than manned missions. Learning about 1 or 2 asteroids will help us very little.

If, against all odds, the manned mission does land on a resource rich asteroid, we would still be lightyears from tractoring the asteroid to a Earth Moon Lagrange point.

 

[EarthlingX]

Prospector missions are precursor missions, as planned.

As for the rest, you obviously haven't seen NASA plans for how to establish base on the Moon and what all is needed. I might check a bit and perhaps drop it in later. It is a rather thick pdf.

Establishing a base is just a first step of many, before there will be any use of Moon resources, so if are dropping wild estimates, 2100.

I don't know why we discuss Moon in this thread ?

 

[csmyth3025]

Prospector missions are precursor missions, as planned....
...I don't know why we discuss Moon in this thread ?

Actually, the core of the debate is whether asteroid/comet utilization is a first step prior to (or in place of) Lunar resource utilization. I think the same amount of resources will be needed for mining, processing and fabricating useful materials from an asteroid as will be needed to do the same thing on the Moon.

The question then comes down to whether asteroids are more accessible than the Moon or vice versa. How much effort will it take to get a usable asteroid to a location where its resources can be exploited, presumably for fabrication of space-based facilities of some sort. How does this compare to the amount of effort needed to accomplish the same end result by utilizing Lunar resources?

Have any reputable studies been done comparing the projected costs, hazards and time frames for these two competing approaches?

Chris

 

[EarthlingX]

Prospector missions are precursor missions, as planned....
...I don't know why we discuss Moon in this thread ?

Actually, the core of the debate is whether asteroid/comet utilization is a first step prior to (or in place of) Lunar resource utilization. I think the same amount of resources will be needed for mining, processing and fabricating useful materials from an asteroid as will be needed to do the same thing on the Moon.

That is a core debate in Moon, Mars, or Asteroid? Which is the best goal? thread, and at least a couple more.

 

[csmyth3025]

Prospector missions are precursor missions, as planned....
...I don't know why we discuss Moon in this thread ?

Actually, the core of the debate is whether asteroid/comet utilization is a first step prior to (or in place of) Lunar resource utilization. I think the same amount of resources will be needed for mining, processing and fabricating useful materials from an asteroid as will be needed to do the same thing on the Moon.

That is a core debate in Moon, Mars, or Asteroid? Which is the best goal? thread, and at least a couple more.

Your point is well taken. I must have overlooked that one because the last post is over a year old.

Chris

 

[MeteorWayne]

Your point is well taken. I must have overlooked that one because the last post is over a year old.

Chris

Not really, since the topic was created Sept 1 of this year; just over a month ago...