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#51 2019-09-10 09:52:50

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Colonizing / terraforming small asteroids

For a cycler, there are many possible candidates.  For Mars missions, we would ideally choose an asteroid that is <100m in diameter and is both Earth crossing (or grazing) and Mars crossing (or grazing).  An orbit that grazes the orbits of both planets would appear most desirable, as it suggests minimal dV needed to match the orbit of the cycler at both ends and of course, it increases the frequency of useful transits.  Wiki has a huge list of minor planets that I am gradually interrogating.

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

Essentials in selecting a candidate cycler are:
(1) Correct orbit (as discussed);
(2) Composition – there is flexibility here, but metallic asteroids probably aren't what we want.

Bonuses:
(1) Presence of water and organics (ideally), but as a minimum, iron oxides in stony asteroids can be reduced to yield oxygen, which dominates propellant mass;
(2) Size: Too small and the asteroid does not warrant a long term investment; Too large and the initial investment is excessive.  About 50-100m across appears to be in the correct range;
(3) Presence of exportable mineral groups (to Earth and Earth orbit) would be a valuable bonus.  For this to be viable, we are probably interested in asteroids with perihelion close to 1AU.


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#52 2019-09-10 11:06:58

tahanson43206
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Registered: 2018-04-27
Posts: 16,746

Re: Colonizing / terraforming small asteroids

For Calliban re #51 ...

In another topic, Terraformer just brought up the concept of tethers.

Tethers have long been proposed as propulsion methods.  You have (I think) received your copy of Heppenheimer.  I was surprised (for some reason) to see that back in 1977, folks were thinking about using tethers (in the form of rigid throwing arms) as a way of propelling the catcher cone to keep it on station to receive packets tossed up from the Moon by electromagnetic launchers. 

However, coming back to your topic here ... and picking up on the cycler option for a well selected asteroid ...

A tether (admittedly of considerable tensile strength) could (theoretically) be used to propel 1/2 of an asteroid in a desired trajectory (ie, Earth/Mars crossing), while the other half goes in the opposite direction.  The trick with such momentum jujitsu is to try to find a useful destination for the secondary "payload".

That said, it might turn out that if there is an asteroid that has an orbit close to one that would work for an Aldrin Cycler (or any cycler), then perhaps the tossed part of the mass need not be the full 50%.  Perhaps a smaller mass could be swung faster.  That is certainly the idea in the Heppenheimer description of the catcher cone propulsion system.

Jerome Pearson would be my go-to person for tether engineering.

I believe he is still with us, but he's getting up there.

(th)

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#53 2019-09-10 11:57:38

Calliban
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From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Colonizing / terraforming small asteroids

A few candidates for Mars cyclers, none of them ideal.  I haven't looked at orbital inclination, which may disqualify some candidates.  Ryugu looks like the best mars cycler candidate from an orbital mechanics point of view.  Do you suppose that the Japanese picked it for that reason?

Aphelion slightly too small for Mars, but perihelion is good for Earth.  Diameter is slightly too large.
https://en.wikipedia.org/wiki/(529366)_2009_WM1

Orbital characteristics look good – but at 20m diameter, the body is on the small side.
https://en.wikipedia.org/wiki/2009_DD45

Aphelion is 0.3AU beyond Mars orbit, but perihelion is good for Earth.  Diameter is too large at 370m.
https://en.wikipedia.org/wiki/(292220)_2006_SU49

Orbital characteristics look good.  I knew there was a reason that the Japanese were interested in this asteroid.  Quite large at 900m diameter.
https://en.wikipedia.org/wiki/162173_Ryugu

Aphelion falls 0.3AU short of Mars orbit and it is small at 30m across.
https://en.wikipedia.org/wiki/1998_KY26

Perihelion is good for Earth, but aphelion is 0.2AU beyond Mars, though perhaps a tolerable orbital parameter.  Another asteroid specifically targeted by the Japanese.  Dimensions are too large for bag enclosure – it is 500m long and 200m wide.
https://en.wikipedia.org/wiki/25143_Itokawa

Perihelion is good for Earth, but aphelion is 0.5AU beyond Mars orbit.
https://en.wikipedia.org/wiki/4660_Nereus

Perihelion and aphelion are both more than 0.1AU from either planet.  Much too large for bag enclosure, though interestingly Eros mass is high enough that natural gravity may balance internal pressure in excavated volumes if they are deep enough.
https://en.wikipedia.org/wiki/433_Eros

Much too large for bag enclosure (2km) and aphelion is 0.3AU beyond Mars orbit.
https://en.wikipedia.org/wiki/1943_Anteros


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#54 2019-09-10 13:19:12

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re #53

Bravo! You're really on a roll here!

With your permission (to be awarded next post, or declined), I'd like to toss another element into your topic ...

You have heard of nanotechnology, of course.

What I cannot know is how much time you've had to study the topic, in light of everything else going on.

One of the members here, kbd512, has mentioned one aspect of nanotechnology (and possibly others) in numerous posts over the past year.

I bring this up because, if you choose a carbonaceous asteroid for your project, then Carbon Nano Tube netting is more than a theoretical possibility.

In that case, there is no need to bring a lot of mass up from Earth, beyond the machinery to produce feedstock for weaving machines, and a number of weaving machines, plus whatever is needed to replace them or repair them if necessary.

Your net, should you go in that direction, would (I understand) have remarkable tensile strength.

(th)

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#55 2019-09-10 18:49:40

SpaceNut
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Re: Colonizing / terraforming small asteroids

Picking the target is just as important as the archeture to be able to work it to the fullest. In fact picking multiple targets can work to if you can intersect the mined commoduties for purpose of sales to continue to fund the work.

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#56 2019-09-11 04:15:20

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re SpaceNut's #55 ...

The list of candidates you've provided jumps out at me as a candidate for Division of Labor, if there are enough active forum members to participate.

It may be obvious to most folks here, but I need a little coaching on how to approach study of one of the candidates (let alone all of them).

SpaceNut's point about looking for possible coincidental candidates sure makes sense, although the Solar System is a big place, and (I'm assuming) the candidates are distributed widely.

I'd also like to suggest using the Anchor option that FluxBB provides.  A post can become an Anchor Point for a specific candidate, so that work on that candidate is not distributed over multiple posts. 

It would take a bit of book keeping on your part, but post #53 above could become an index to work done by forum members for specific candidates.

In any case, thanks (again) for collecting the list of candidates! 

(th)

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#57 2019-09-11 19:19:14

SpaceNut
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Re: Colonizing / terraforming small asteroids

Much like the My Hacienda On Mars topic one could assign asteroplot#### to each objective for development as business opportunities.
Calliban Initial post of target selecting targets
minor planetoids
update of list of plausible

its a matter of putting details to each for what can be gained after we land and start to process to make them habitat cyclers...

https://www.nasa.gov/planetarydefense/faq
https://www.nasa.gov/planetarydefense/overview
https://www.nasa.gov/planetarydefense/neoo

The vast majority of NEOs that enter Earth’s atmosphere disintegrate before reaching the surface (and more than 100 tons of dust particles disintegrate in Earth’s atmosphere daily), those NEOs that are larger than around 98 to 164 feet (30 to 50 meters) in size and could cause widespread damage in and around their impact sites. A potentially hazardous object (PHO) is a near-Earth object whose orbit brings it within 4.7 million miles (7.5 million km) of Earth’s orbit, and is greater than 500 feet (140 meters) in size.

Hopefully GW might find the time to tutor Newmars on what is the launch window for a mission to any using Space x falcon 9 heavy and dragons for getting to them once men are needed for the processing of them. How do we direct launch or time it from LEO for getting to them.

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#58 2019-09-12 00:43:36

Calliban
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From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Colonizing / terraforming small asteroids

If the orbital characteristics are reasonably close to what is needed, we could use mass drivers to optimise the orbit.  Mining the asteroid and hollowing out internal spaces will generate a lot of rubble that could be used as reaction mass.  This might be feasible if the delta-v required to adjust the orbit is no more than 100m/s, say.  Where this may prove impractical is for bodies whose orbit is not well aligned to the plane of the solar system.

I believe that Ryugu is one of the best candidates for an Earth-Mars cycler and that probably has a lot to do with why the Japanese are so interested in it.  I would propose that this should be considered as the baseline for further discussion.  It is also close to spherical in shape, making it an efficient option for enclosure in a pre-stressing restraining bag.

I previously calculated that the zylon restraining bag for a 100m spherical asteroid would weigh 98 tonnes, if rated to contain a 50KPa pressure with a sufficient safety factor.  Given that the mass of a pressure vessel scales with volume, a similar but larger restraining bag for Ryugu (900m diameter) would weigh 71,442 tonnes.

This sounds like an unachievable mass to consider launching from Earth.  However, Musk believes that his reusable starship will be capable of lowering launch costs to $200/kg in regular operation.  If we could divide the restraining bag into smaller hexagonal sections that can subsequently be clipped or stitched together; some 240 starship launches would be needed to deliver the bag to Low Earth Orbit.  Total cost would be $14.4bn.  If we want to spin Ryugu to produce lunar levels of gravity at its equator, the required mass of the bag would roughly double and so would launch cost.  If an electrically propelled transfer vehicle could be used to deliver the bag sections to Ryugu, then the project might be accomplished at a cost of ~$50bn.

Whilst this is a large sum of money, it may be a good investment.  Ryugu weighs 450 million tonnes.  If it can be mined, much of this material could be returned to Earth orbit to support space manufacturing, or even to Earth surface for relatively valuable elements.  The volume of the asteroid is 380million cubic metres.  If the asteroid is mined to excavate roughly half of its volume, this would ultimately allow sufficient space for tens of thousands of passengers travelling between Earth and Mars.  The capital cost of the project can also be offset against the reduction in cost of spacecraft needed to transfer colonists between Earth and Mars, which would be much smaller if a cycler is used, as it only needs to house the colonists for a shorter period of time.

We would ideally attempt to engineer the bag segments such that they easily clip together; are covered in solar cells to generate power; contain heat transfer channels allowing them to be used to dump waste heat; and include an internal void that can be filled with compacted dust to protect the tensile material from meteorite impacts.

Last edited by Calliban (2019-09-12 03:23:50)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#59 2019-09-12 04:55:46

Calliban
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From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Colonizing / terraforming small asteroids

It turns out that Ryugu is a mixed carbonaceous and G-type (clay) asteroid; probably a rubble pile consisting of coalesced debris from both.

https://en.wikipedia.org/wiki/162173_Ryugu

This has important implications for mission architecture.  If Ryugu contains a lot of carbon and oxygen (in silicate clays) then it has most of the feedstock necessary for CH4/LOX propellant manufacture.  Carbon is also a reducing agent in the production of iron.

If the transit between Ryugu and Earth/Mars is relatively short (days - a week), then passengers can be housed in small jet-aircraft type fuselages with little requirement for space or consumables.  Most or all of the fuel needed for transfers between the asteroid and Mars/Earth can be produced on the asteroid.  The small chemically fuelled transfer vehicle would presumably need to rendezvous with other vehicles in Mars/Earth orbit, whose purpose is specifically to ferry people and materials between LEO/LMO and the surfaces of both respective planets.

Ultimately, this should make the transit between Earth and Mars both cheaper and safer, at the expense of developing the asteroid into a viable cycler in the first place.

baseline mission architecture:

1. Ryugu is developed into a combined asteroid mine / cycler, whose task is to deliver minerals to Earth orbit and convey passengers between Earth orbit and Mars orbit.  The cycler material will be processed insitu to produce oxygen for crews and propellant, and possibly to grow food using native carbon and oxygen.  A huge investment will be required to convert the asteroid into a workable cycler - probably several tens of billions of dollars.  This is partially amortised by export of materials back to Earth orbit and Earth surface.

2. Missions to Mars will use a reusable starship type rocket to rendezvous with a reusable transfer vehicle in Earth orbit.  The transfer vehicle will take on passengers and extra propellant and will carry passengers to the cycler (dV ~6km/s?), whilst the starship upper stage returns to Earth surface;

3. Passengers will live in the cycler using its materials to supply all consumables for the duration of the trip and using propellant derived from the asteroid to refuel the transfer vehicle.

4. Upon Mars approach, passengers will board the transfer vehicle once again, and complete the short trip to Mars orbit, burning propellant to complete orbital injection.

5. The transfer vehicle will rendezvous with a reusable Mars SSTO that cycles between Mars surface and low Mars orbit.  It will transfer people and payload and take on some fresh propellant.  Ultimately, fresh propellant may be produced on Phobos, but this implies more capital investment.

6. The transfer vehicle will then transfer people and payload from low Mars orbit back to the cycler.

7. Upon Earth approach, the transfer vehicle is refilled with propellant from the cycler and achieves Earth orbital injection with a propulsive burn.

8. The cycle repeats again.

Last edited by Calliban (2019-09-12 05:16:30)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#60 2019-09-12 06:54:44

tahanson43206
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Registered: 2018-04-27
Posts: 16,746

Re: Colonizing / terraforming small asteroids

For Calliban ...

Calliban wrote:

It turns out that Ryugu is a mixed carbonaceous and G-type (clay) asteroid; probably a rubble pile consisting of coalesced debris from both.

https://en.wikipedia.org/wiki/162173_Ryugu

Your post above with the focus on Ryugu and mission structure deserves (and hopefully will receive) full discussion by members here.

This reply is offered to bring focus to the note made earlier about the use of Carbon to make a net from indigenous materials, instead of transporting one from Earth. 

Thanks for continuing to develop this topic! I think it has potential to lead to actual activities by real people in the real universe.  It will take persistence in the face of fluctuating levels of response from members.  Members of the forum have busy lives outside the forum (of course) so their participation waxes and wanes as time, energy and interest vary.  If you can tend the topic at least weekly, I'm hoping that will be enough to sustain it, because the topic itself should inspire present and future members.

One element you could add (if possible) would be a timeline you would like to see for a mission to Ryugu.

And (I just realized) the Japanese may be planning a follow up mission already.  it would be great if someone could contact their team to see what they have in mind.

Please note that SpaceNut extended an invitation to GW Johnson to lead a tutorial on Orbital Mechanics to plan a mission.  Clearly the Japanese have mastered the mathematics and computer programming needed to achieve a successful docking, as you pointed out.  It is possible that no one currently on the forum can duplicate the achievement, but there are two answers: First, we can attempt to gain mastery of the subject, and Second, we can encourage folks with the needed skills to join and support the undertaking.

I would be willing to invest in a beginner's text for Orbital Mechanics (if such a thing exists).   I'd like to see if it is better to launch all missions from Earth, as is done at present, or if it would be better to start out-of-plane missions from LEO or GEO or perhaps even L1.

(th)

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#61 2019-09-12 16:30:01

SpaceNut
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From: New Hampshire
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Posts: 28,747

Re: Colonizing / terraforming small asteroids

I think size is as well as materials they are made of also equate into just a few business models.

Size 100 -150 I think are mine until gone for the purpose of exporting to where the materials can be used.
size 150 upward would be mine out the center to create habitat space for man to have a safe habor in as space cyclers. Sure some of the materials will be needed as insitu use but there my still be some to export. Its this size and quite possibly the unepected that makes doing it possible for much more than rock...

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#62 2019-09-12 16:42:18

Calliban
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From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Colonizing / terraforming small asteroids

Somewhat off topic, this asteroid has perihelion about 0.02AU from Earth orbit, and Aphelion only 0.5AU from Jupiter orbit.

https://en.m.wikipedia.org/wiki/2016_WF9

The asteroid is volatile rich and probably an extinct comet.  Its orbital characteristics and composition make it ideal for accessing the Jupiter system, the Trojans and the outer belt.

Unfortunately, Jupiter's year is so long, that we could wait decades for the cycler orbit to line up with the orbits of either Jupiter or its Trojans.  This would work if a relatively small team were to travel to the asteroid and use AI, robotics and nanotechnology to transform slowly over a period of decades into a habitat and fuel station.  Humans would arrive in large numbers during a close pass between the asteroid and Earth, presumably on the same orbit on which the asteroid makes a close pass of Jupiter.  In the decades before, the asteroid is effectively cannibalised into fuel, consumables and reaction mass that can then be used to springboard a large number of colonists into the Jupiter system, or more likely in my opinion, to the ice-rich Jupiter Trojans.

This is a long-term objective because the Trojans are some 5 times further from the sun than Earth. They are good targets for colonisation only after nuclear fusion is mastered.

Last edited by Calliban (2019-09-12 16:48:01)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#63 2019-09-12 16:59:26

Calliban
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From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Colonizing / terraforming small asteroids

SpaceNut wrote:

I think size is as well as materials they are made of also equate into just a few business models.

Size 100 -150 I think are mine until gone for the purpose of exporting to where the materials can be used.
size 150 upward would be mine out the center to create habitat space for man to have a safe habor in as space cyclers. Sure some of the materials will be needed as insitu use but there my still be some to export. Its this size and quite possibly the unepected that makes doing it possible for much more than rock...

Asteroids in this size range are easier to work with, as upfront investment costs are more affordable and we do not need ISRU to build the first restraining bag.  Hence, this is a foot-in-the-door concept.  We are not necessarily looking for an asteroid suitable as a Mars cycler in the first instance.  We are looking for the asteroid that makes a close approach to a candidate cycler asteroid and is small enough to begin working at minimal start up cost.   If an asteroid of this size range is enclosed with an Earth-made bag, excavated materials can be processed into basalt fibre and used to manufacture segments for a larger restraining bag for a larger asteroid.  We would put our glass melting vats and weaving machines in tunnels and manufacture a larger bag under habitable conditions.

A 100m diameter stony asteroid, weighs 1.3million tonnes.  If 20% of that mass is used to manufacture basalt fibre, then the resulting bag would be sufficient to enclose a 1km diameter asteroid and allow it to be spun up to lunar levels of gravity.  The manufacturing and mining can be carried out in habitable environments, making it much easier.  Hence, an initial investment of 98 tonnes in a restraining bag for a 100m diameter asteroid, can ultimately allow access to an asteroid weighing a billion tonnes and so on. The orbit of the asteroid could be adjusted to allow regular close approaches of Earth.

Last edited by Calliban (2019-09-12 17:09:48)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#64 2019-09-12 21:09:57

SpaceNut
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Re: Colonizing / terraforming small asteroids

The size for what we would reduce to rubble for materials may need to be raised but at some point there is a direct cutoff for what can be done with our launch abilities for payloads to any of them.

A burst of asteroid activity in Europe

ESA estimates, there are 878 asteroids in the 'risk list'. This ESA catalogue brings together all asteroids we know of that have a 'non-zero' chance of impacting Earth in the next 100 years - meaning that an impact, however unlikely, cannot be ruled out. http://www.esa.int/Our_Activities/Space_Safety/

More than 800 asteroids are at risk of hitting Earth in the next 100 years, ESA warns

A burst of asteroid activity in Europe

Asteroid_danger_explained_printlarge.png

The relates to the task of identification once there in that Are we prepared for a new era of field geology on the moon and beyond?

http://neo.ssa.esa.int/risk-page

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#65 2019-09-14 09:17:34

SpaceNut
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Re: Colonizing / terraforming small asteroids

In the orbital mechanics topic we have discusion going with what does it take to plan a mission. Such missions as this would require software tools and much more so as to be able to determine what is required for a launch vehicle and what would be its payload capability for a selected destination.

Predicting Apophis' Earth Encounters in 2029 and 2036 was meantion as a possible attempt to plan out such a mission to.

I believe basedon some numbers that a space x Falcon 9 Heavy could carry out such a mission with the use of COTS hardware. Using base designs from Nasa for rovers and orbiters plus nano (cube) sats as well. We know the capability that both can yield for years of service to survivability as well.

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#66 2019-09-14 09:34:14

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re topic...

For SpaceNut re #65...

The topic of carbon fiber netting shows up in this analysis of the Apophis asteroid path options.

I appreciated the author's detailing of influences on the path of the asteroid.
https://cneos.jpl.nasa.gov/doc/apophis/

A change somewhat greater than this minimum would be required to allow for prediction uncertainties. For Apophis, scaling up to distribute 250 kg (550 pounds) of a reflective or absorptive material (similar to the carbon fiber mesh being considered for solar sails) across the surface could use the existing radiation forces to produce a 6-sigma trajectory change, moving at least “99.9999998” percent of the statistically possible trajectories away from the Earth in just 18 years.

This seems (to me at least) like a worthwhile undertaking.  It could be a global project. 

(th)

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#67 2019-09-14 22:32:08

SpaceNut
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Re: Colonizing / terraforming small asteroids

The carbon was to make a solar sail but the surface of it must be reflective and that is not what carbon is as its an obsorber. A solar sail would also need a ridgid support system to support the sail for use.
The was to correct the path such as to devert the asteriod from striking the earth.

asteroid-apophis-2029.gif

On April 13, 2029, a speck of light will streak across the sky, getting brighter and faster. At one point it will travel more than the width of the full moon within a minute and it will get as bright as the stars in the Little Dipper.

apophis7.jpg

Apophis’ surface and asteroid’s interior will see torque caused by the Earth’s gravitational pull will cause surface and interior disruption to Apophis, scientists have a unique opportunity to observe its otherwise inaccessible mechanical properties.

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#68 2019-09-15 06:57:36

SpaceNut
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Re: Colonizing / terraforming small asteroids

Seems we have lots to chose from for a mission to an asteriod. A Skyscraper-Size Asteroid Will Zoom Past Earth Saturday Night

An asteroid as wide as a skyscraper is tall will glide harmlessly past Earth tomorrow night (Sept. 14).

Asteroid 2000 QW7 is between 1,000 and 2,000 feet wide (300 to 600 meters) and will fly by at a distance of 3 million miles (5 million kilometers) from our planet at 7:54 p.m. EDT, according to NASA's Jet Propulsion Laboratory. The asteroid, moving 14,361 mph (23,100 km/h), poses no danger to Earth on this pass.

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#69 2019-09-15 07:17:23

tahanson43206
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Re: Colonizing / terraforming small asteroids

SearchTerm:ApophisHomework

For SpaceNut re #67

Thanks for that helpful GIF ... It seems to strengthen the suggestion that a mission to Apophis might be set up as a two stage project.  The first phase would be delivery of the intercept package to GEO.  That package would then have a large part of the velocity it would need to achieve a matching orbit.  There is a significant plane change involved, in addition to the velocity increase.

I'm planning to take a look at some of the many links you provided in this topic and others for Apophis mission planning.

Edit 2019/09/15 Instead of cluttering up the forum database with separate posts, my idea here is to use this post as an anchor for brief summaries of links SpaceNut (and others) have provided or may provide in support of Calliban's topic.

I'll be using the Search Term added above to return to this anchor post quickly.  The process could easily take a month or more, because SpaceNut has similarly gifted readers of the OrbitalMechanics topic.

(th)

Last edited by tahanson43206 (2019-09-15 09:35:58)

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#70 2019-09-15 08:48:59

SpaceNut
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Re: Colonizing / terraforming small asteroids

Then you should like this as
Preliminary Design of a Crewed Mission to Asteroid Apophis ...
www.adrc.iastate.edu/files/2012/09/AIAA-2010-8374.pdf

paper focuses on mission design as well as the system architecture that would be required for this mission to Apophis. The primary mission will be a 180 day mission in the 2028-2029 range during the Earth-Apophis close encounter on April 13th, 2029. In an effort to reduce mission requirements mission analysis for missions


MIT Students Design Mission to Huge Asteroid Apophis | Space
https://www.space.com/37117-mit-student … ssion.html

MIT Students Design Mission to Huge Asteroid Apophis. Asteroid Apophis, which measures 350 meters across and weighs 20 million metric tons, will come within 19,400 miles (31,300 kilometers) of our planet during its 2029 flyby. The asteroid is expected to closely buzz past Earth again in 2036.

Something for Louis

Mission to Apophis - David Morrison (SETI Talks) - YouTube
https://www.youtube.com/watch?v=TI0Rf0kyFSE

This talk focuses on a low-cost rendezvous mission to NEA Apophis

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

https://www.jpl.nasa.gov/asteroidwatch/

Design Concepts for a Small Space-Based GEO Relay ...
https://ntrs.nasa.gov/archive/nasa/casi … 010039.pdf

The main purpose of the Small Space-Based Geosynchronous Earth orbiting (GEO) satellite is to provide a space link to the user mission spacecraft for relaying data through ground networks to user Mission Control Centers. The Small Space Based Satellite (SSBS)

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#71 2019-09-16 05:49:59

tahanson43206
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Re: Colonizing / terraforming small asteroids

For SpaceNut and Calliban ...

Starting review of the Apophis links ...

SpaceNut wrote:

Then you should like this as

MIT Students Design Mission to Huge Asteroid Apophis | Space
https://www.space.com/37117-mit-student … ssion.html

MIT Students Design Mission to Huge Asteroid Apophis. Asteroid Apophis, which measures 350 meters across and weighs 20 million metric tons, will come within 19,400 miles (31,300 kilometers) of our planet during its 2029 flyby. The asteroid is expected to closely buzz past Earth again in 2036.

The student design is to launch in 2026, to achieve a flyby in 2029.  The 20 student team was led by two professors, one of whom had returned from a tour of duty at NASA,  The paper was described by a NASA reviewer as "nearly ready for a NASA proposal".

The mission objective was to gather as much data as possible while doing a flyby.

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My objective in reviewing the links SpaceNut provided is to try to find out if anyone has created a web site mission planner suitable for this specific kind of problem.  The solution worked out by the MIT students should pop out of a calculator if the input parameters are chosen to match those they used.

(th)

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#72 2019-09-16 07:21:41

tahanson43206
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Registered: 2018-04-27
Posts: 16,746

Re: Colonizing / terraforming small asteroids

Dr. David Livingston will be hosting an interview with a lawyer to discuss (among other things) property rights in space:

5. Sunday, Sept. 15, 2019 12-1:30 PM PDT, (3-4:30 PM EDT, 2-3:30 PM CDT): We welcome back WAYNE WHITE, noted space attorney regarding property rights and other commercial space legal issues.

(th)

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#73 2019-09-29 07:32:36

tahanson43206
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Registered: 2018-04-27
Posts: 16,746

Re: Colonizing / terraforming small asteroids

For Calliban re topic ...

Please keep this topic going ... it has greater potential for a long life than many topics introduced into the forum.

I'll toss a mini-vision your way, in hopes of encouraging further development of this topic, and the underlying knowledge in archive here.

As I recall from previous discussion, you are aware of the Stanford Torus Summer Study, and of the books that were inspired by that effort back in the 70's.

In thinking about your topic recently, it occurred to me that the Stanford Torus design could be shrunk to a minimal size, suitable for sustaining comfortable living for a crew engaged in working an asteroid. 

Earlier, in another topic, someone (possibly SpaceNut) posted an image of a concept for a space station for a LEO hotel.  The interesting aspect that I would like to bring back for discussion here, was the idea of docking a number of space ship upper stages in a ring, so the complex could be rotated for partial simulated gravity.

[void liked the phrase "simulated gravity", and I've decided it is simpler to type than centrifugal gravity]

My idea (for your consideration) is to fly a number of upper stages to an asteroid to be mined, to dock them into a ring, and then to build a radiation shield out of asteroid rubble until the conditions inside the shield are acceptable for humans.  At that point, the mining crew could arrive and begin telepresence operations to collect useful material from the object, and arrange for shipment to the customer (Earth or other ) .

Thus, the challenge for an engineer (should you accept it) is to compute the mass requirements for such a habitat, and (perhaps) to sketch some considerations for planning one.

Edit: Please keep the fundamental design feature of the Stanford Torus ... 1 RPM and 1 G simulated gravity.  The goal here is to create an environment that workers will appreciate, both while on the job, and after they return to Earth.

(th)

Last edited by tahanson43206 (2019-09-29 07:45:06)

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#74 2019-09-29 10:51:22

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,747

Re: Colonizing / terraforming small asteroids

The vehicle would need a rotatable engine pod for the ship to land horizontally.

spatap2207.jpg

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#75 2019-10-14 10:08:36

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 16,746

Re: Colonizing / terraforming small asteroids

For SpaceNut re #74

The engines on the vehicle you've shown us may NOT be for landing.   If this vehicle is a cargo vessel, and IF it is intended to be loaded with mass from the object below, then those engines would work fine for a take off.

Depending upon the size of the object, smaller jets mounted in the pods on the sides may be sufficient to support the mass of the vehicle.

For Calliban ... this topic has languished for more than a month.

Please give it a boost with an insight about your chosen focus, or something related if you want to expand a bit.

(th)

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