Obama's asteroid goal: tougher, riskier than moon

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bdewoody

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you must watch and believe too many silly sci fi movies to think we need to send men to deflect an incoming asteroid. Now having a manned telescope and radio telescopes on the moon will have greater ability to detect an incoming rock and hopefully provide time to mount a defence again from the moon, ie. a super poweful laser or solar beam.
 
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neutrino78x

Guest
bdewoody":47787mdn said:
you must watch and believe too many silly sci fi movies to think we need to send men to deflect an incoming asteroid.

lol, well, I was thinking you would send the people to have the adaptation ability. :)

Now having a manned telescope and radio telescopes on the moon will have greater ability to detect an incoming rock and hopefully provide time to mount a defence again from the moon, ie. a super poweful laser or solar beam.

Neither of which needs people though...

--Brian
 
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rockett

Guest
neutrino, then why do we need to go anytwhere? Send robots, let the computers analyse the data, and stay home.
No need to go to asteroids or Mars either, except for political grandstanding, and more boots and flags.

At least extending your logic, that seems to be what you are advocating.
 
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MeteorWayne

Guest
I posted this in another thread, but it's directly related to this one as well, so I'll copy most of it here:



The moon is a far easier target for a mission.

It's relatively close.
It's always (roughly) the same distance from earth.
It's always moving at (roughly) the same speed in a (roughly) circular orbit around home.

Asteroids are not like that.

Between now and 2200 AD, only 16 asteroids come as close or closer to the earth than the moon.
They have relative velocities to the earth ranging from 1.91 to 26.28 km/sec.
(The moon of course has an average relative velocity of zero, though it is in orbit)
The one at 1.91 km/sec is only ~8 meters in diameter. Not of interest.
3 more occur in the next 2 years; they're out.
That leaves a dozen.

One of the closest of those 16 is of course Apophis in 2029, and it's big (~270 m), but the relative velocity is 7.42 km/s, which means that each day it moves 1.667 times the average earth-moon distance. That means for a two week surface mission, it will move 23 times the lunar distance or 9 million km. So you have to travel 12 times the distance to the moon, match speeds with it (unless you like that bug on a windshield feeling, and it's gravity is too feeble to help) then hop off 12 LD away, and get rid of all that speed to return to earth. Of course you could just hop on, since it's in a 0.9 Y solar orbit, but oops, there's a problem with that. The 2030 close approach is 0.92 AU, about the distance from the earth to the sun. 2031: 1.6 AU, 2032: 2.0 AU, 2033: 2.2 Au....you get the idea. The next relatively close approach is of course in 2036, projected at 0.34 AU, unless of course the 2029 close approach changes the orbit through that tiny keyhole and it will impact earth. In that case, being on it, assuming you survive the 9 years in the first place, would not be desirable.

The 3 larger asteroids of the 16 are moving 10.24, 26.02, and 26.28 km/s.

That's just a quick look.
 
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EarthlingX

Guest
How about Phobos ? Co-orbitals ? How will WISE change that picture ? You think a couple of m wide rock at SE L3 or L4 wouldn't be of use ? How do we know there is none such there ?

AFAIK high Isp engines can not be used for Moon landing and launch, and if you plan to stay longer on the surface, you face similar environmental problems, as if you were in space. At least before you start digging, but drilling into asteroid might be easier.
There is also annoying day-night cycle, which at the end means more added mass, before anything else becomes real.

If you are in space, or docking to asteroid, this is not needed, and you can do a lot, and a lot more, with just a sec or less light distance.

You also get a ship, which just needs a lander. I also don't see anything wrong with habitat modules being used as a ground base, when you can land them.

Having a lander, which could do a powered landing, would cut through all of this, but that might be SSTO story.

Main problem is, as usual, money - what first.

I wouldn't mind having a room on the Moon with the Earth view, and well, there are also other places i could live with :cool:

There is also a possibility to change asteroid orbit, for which i'm sure will be one of the basics of a future space civilization, and that might get demonstrated in one of the future NASA missions.
 
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bdewoody

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At least on the moon we have predictable day night cycles whereas on an asteroid even just landing a manned craft could severely alter it's spin and possibly trajectory. And what about cme's? On the moon we can build shelters, probably noy on an asteroid.
When you sit down and carefully go over all the aspects and look seriously at what we are capable of with current technology it becomes obvious that the moon is the logical goal for immediate manned missions. If NASA is forced by Obama and congress to pursue this fantasy goal of putting men on an asteroid it will either end up in the worst case a tragedy or putting an end to the USA's manned space program for decades which I believe is Obama's true goal.
 
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EarthlingX

Guest
If we are talking about beliefs, i'm very much convinced that was Bush' intention, since he wanted to drop ISS, and start building a rocket which could never fly, just suck money, while destroying advanced programs, and ending proven means of human flight.

He also managed to stop American space industry, by stopping exports, cutting companies from their markets. Very visionary.
 
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bdewoody

Guest
Well I guess I started it and I don't like to get political in the space forums but here goes. According to most Bush bashers he isn't smart enough to have planned anything so cunning. At least he set a goal that is attainable. He wasn't responsible for the constellation design or the Orion and I think it's unfair to say the design is unworkable. Nobody ever proved to me and many others that it was fatally flawed.

Obama and most liberal Democrats would much rather see NASA's budget spent on welfare and free medicine for the masses, They won't admit it face to face but down deep that is their goal.
 
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neilsox

Guest
Near the equator of the moon day lasts about two weeks followed by about two weeks of night. Is that significantly better than 4 hours of day followed by 4 hours of night near the equator of a typical asteroid? A very few asteroids have the same day/night scheduled as Earth. A thousand ton lander does not change the orbit much of a million ton asteroid. We probably don't want to land on an asteroid with less than a million tons of mass = dimensions of about 80 meters. The inertia of the asteroid is about 1000 times the inertia of the space craft which is equivalent to near zero for a gentle landing. My guess is the risk and fuel is about the same, for the more favorable asteroids with close to the same orbit as earth = near circular orbit. Using asteroid material for radiation shielding will be different than using moon material but likely no more difficult. I agree a delayed return to Earth will have to wait for decades unless our space technology improves. The return to Earth schedule will be tight and unforgiving, so a long term stay should be a planned for possibility. The arrival of a cheap unmanned supply rocket just before or just after the arrival of the manned rocket should allow the astronauts to survive for decades in a tiny mass center of the asteroid habitat. Boring and uncomfortable, but better than death if the planned return trip becomes unsafe, due to minor glitches. Neil
 
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EarthlingX

Guest
bdewoody":1mmb59ld said:
Well I guess I started it and I don't like to get political in the space forums but here goes.
I did not notice you avoiding politics, quite contrary.
bdewoody":1mmb59ld said:
According to most Bush bashers he isn't smart enough to have planned anything so cunning.
That's what his buddies did, those with which he shared interests, like oil companies.
bdewoody":1mmb59ld said:
At least he set a goal that is attainable.
That would be ? Drop ISS : check. Kill tech : check. Kill alternatives : check. ...
bdewoody":1mmb59ld said:
He wasn't responsible for the constellation design or the Orion and I think it's unfair to say the design is unworkable.
And Obama is responsible for everything and then some more ? Weather too ? If that design is so workable, why it doesn't compete in COTS ?
bdewoody":1mmb59ld said:
Nobody ever proved to me and many others that it was fatally flawed.
At least a couple of times on this forum, with every detail in at least a couple of threads, easy to find.
bdewoody":1mmb59ld said:
Obama and most liberal Democrats would much rather see NASA's budget spent on welfare and free medicine for the masses, They won't admit it face to face but down deep that is their goal.
Very non-political and rational.
 
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HopDavid

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EarthlingX":1bhfc12p said:
How about Phobos ? Co-orbitals ? How will WISE change that picture ? You think a couple of m wide rock at SE L3 or L4 wouldn't be of use ? How do we know there is none such there ?

Landing on Phobos would take less delta V than landing on the moon.

But Hohmann launch windows occur each earth-Mars synodic period, about 2.14 years. One way trip time is about 8 months.

In contrast, from LEO, lunar launch windows open every two weeks. One way trip time is about a week.

Round trip light time to the moon is 2.6 seconds. This makes earth based teleoperation more viable on the moon. Which makes robotic mining of lunar propellent more plausible than mining propellent from NEOs.

There is thought to be 600 million tonnes of water at the lunar south pole as well as 600 million tons of ice at the north pole. Thought to be in 2 meter or more sheets of ice. In addition, the lunar crust is about 40% oxygen. So the moon could be an excellent source of propellent.

The moon is about 2.5 km/sec from EML1 and EML2. Round trip reusable tankers can ship lunar propellent to EML1 and 2 as well as LEO.

EML1 has a 2.4 km/sec advantage over LEO for any Beyond Earth Orbit destination. Mars, Phobos, NEOs. Ceres, whatever.

Propellent mines on the moon as well as propellent depots in LEO and EML1 would be the golden spike that opens transportation to the solar system.
 
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rockett

Guest
HopDavid":3axg8suh said:
In contrast, from LEO, lunar launch windows open every two weeks. One way trip time is about a week.

Round trip light time to the moon is 2.6 seconds. This makes earth based teleoperation more viable on the moon. Which makes robotic mining of lunar propellent more plausible than mining propellent from NEOs.

There is thought to be 600 million tonnes of water at the lunar south pole as well as 600 million tons of ice at the north pole. Thought to be in 2 meter or more sheets of ice. In addition, the lunar crust is about 40% oxygen. So the moon could be an excellent source of propellent.

The moon is about 2.5 km/sec from EML1 and EML2. Round trip reusable tankers can ship lunar propellent to EML1 and 2 as well as LEO.

EML1 has a 2.4 km/sec advantage over LEO for any Beyond Earth Orbit destination. Mars, Phobos, NEOs. Ceres, whatever.

Propellent mines on the moon as well as propellent depots in LEO and EML1 would be the golden spike that opens transportation to the solar system.
That is the best and most immediate reason I can think of for going to the moon first. The second best reason is developing the technology to develop and use in-situ resources for sustaining human habitation. Those lessons would apply to Mars, some asteroids, and other destinations.

Lunar ice makes me question the whole rationale of the current administration's avowed goal. It is a game-changer in overall strategy for exploration...
 
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EarthlingX

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HopDavid":3u4qzl0h said:
EarthlingX":3u4qzl0h said:
How about Phobos ? Co-orbitals ? How will WISE change that picture ? You think a couple of m wide rock at SE L3 or L4 wouldn't be of use ? How do we know there is none such there ?

Landing on Phobos would take less delta V than landing on the moon.

But Hohmann launch windows occur each earth-Mars synodic period, about 2.14 years. One way trip time is about 8 months.

In contrast, from LEO, lunar launch windows open every two weeks. One way trip time is about a week.

Round trip light time to the moon is 2.6 seconds. This makes earth based teleoperation more viable on the moon. Which makes robotic mining of lunar propellent more plausible than mining propellent from NEOs.

There is thought to be 600 million tonnes of water at the lunar south pole as well as 600 million tons of ice at the north pole. Thought to be in 2 meter or more sheets of ice. In addition, the lunar crust is about 40% oxygen. So the moon could be an excellent source of propellent.

The moon is about 2.5 km/sec from EML1 and EML2. Round trip reusable tankers can ship lunar propellent to EML1 and 2 as well as LEO.

EML1 has a 2.4 km/sec advantage over LEO for any Beyond Earth Orbit destination. Mars, Phobos, NEOs. Ceres, whatever.

Propellent mines on the moon as well as propellent depots in LEO and EML1 would be the golden spike that opens transportation to the solar system.
It would seam, that EML1 might be the farthest step, before deciding on the destination. It would also give a little less lag for tele-operation on the Moon. I don't see a need for human Moon landing at this point, it is just an unnecessary complication.

Burning, as far as we know, limited amounts of Lunar water might also not be the best strategic decision in the long run, if you plan on having a self-sustained colony there.

Before anyone starts with 'there's plenty of water on the Moon', just a note, that since ISRU was deemed useless, not much has been done about using it in the last couple of years. Please prove me wrong.
 
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scottb50

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EarthlingX":1obbse7p said:
HopDavid":1obbse7p said:
EarthlingX":1obbse7p said:
How about Phobos ? Co-orbitals ? How will WISE change that picture ? You think a couple of m wide rock at SE L3 or L4 wouldn't be of use ? How do we know there is none such there ?

Landing on Phobos would take less delta V than landing on the moon.
Obviously, it would take more delta V to get there, but not that much more. but landing would take less on Phobos.

But Hohmann launch windows occur each earth-Mars synodic period, about 2.14 years. One way trip time is about 8 months.

Landing on an asteroid would take even less, what's the point? Landing on either is pretty much the same thing, just like the moon. Landing on the floor in your living room is the same thing, a lot more variables in the living room actually, but define it and it can be flown.

It's not magic, the same principals are universal.
 
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neilsox

Guest
A reactor would likely shorten the travel time and increase the options for a manned mission, but it could much delay the the first mission, as reactor details are presently unknown and need testing in space. Reactor and PV panels provide a back up if one system works poorly.
Likely we are thinking near Earth asteroid = NEO. Asteroid mass is likely 1000 plus times the space craft mass, so we can't move the asteroid much if we are going to have reaction mass for the return trip. The return trip will take decades if we have too little reaction mass, so we want a sizable reserve of reaction mass. I agree the technology will advance slower until we set firm dates for the missions. Neil
 
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rockett

Guest
neilsox":2sq9o92c said:
so we can't move the asteroid much if we are going to have reaction mass for the return trip. The return trip will take decades if we have too little reaction mass, so we want a sizable reserve of reaction mass. I agree the technology will advance slower until we set firm dates for the missions. Neil
So we use the asteroid for reaction mass:
Paper - Multiple Mass Drivers as an Option for Asteroid Deflection
http://www.google.com/url?sa=t&sour...r8SRCg&usg=AFQjCNGsNG5eABNdd6-PgLuSK3Bfy4AMaQ

Asteroid Mitigation
http://ssi.org/reading/papers/asteroid-mitigation/

Asteroid Eaters: Robots to Hunt Space Rocks, Protect Earth
http://www.space.com/businesstechnology/technology/madmen_techwed_040519.html
 
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HopDavid

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EarthlingX":3s3nhmdu said:
HopDavid":3s3nhmdu said:
It would seam, that EML1 might be the farthest step, before deciding on the destination. It would also give a little less lag for tele-operation on the Moon. I don't see a need for human Moon landing at this point, it is just an unnecessary complication.

I am hoping robots can do the job. If so, lunar exploitation could be far less expensive.

EML1 or 2 could be better places for teleoperation. About 1/6 the light lag from earth and a lot less delta V to reach.

EarthlingX":3s3nhmdu said:
Burning, as far as we know, limited amounts of Lunar water might also not be the best strategic decision in the long run, if you plan on having a self-sustained colony there.

Before anyone starts with 'there's plenty of water on the Moon', just a note, that since ISRU was deemed useless, not much has been done about using it in the last couple of years. Please prove me wrong.

Well, I don't deem ISRU useless. That's a short sighted view, in my opinion. I can hope for a change of guard with a more sensible outlook.

Chandrayan's Mini SAR seems to indicate there's ice sheets two or more meters thick. Dr. Spudis' estimates 600 million tonnes of ice at each pole.
 
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HopDavid

Guest
Landing on Phobos would take less delta V than landing on the moon.

Obviously, it would take more delta V to get there, but not that much more. but landing would take less on Phobos.

That's right.

From LEO, Trans Lunar Insertion is 3.2 km sec. Trans Mars Insertion is about 3.6.

Landing on the moon takes about 2.5 km/sec if you ignore gravity losses. But I would expect some gravity losses would be suffered while hovering and descending.

Exiting the earth to Mars Hohmann and matching velocities with Phobos would take about 2 km/sec.

So you're talking moon 5.7 vs Phobos 5.6 km/sec.

But there are other things to consider:

Trip time
Moon about a week vs Phobos 7 or 8 months

Launch windows from LEO
Moon about every two weeks vs Phobos about every 2.14 years.

Most importantly the moon has volatiles about 2.5 km/sec from EML1. If aerobraking drag passes are used, lunar propellent are a little more than 3 km/sec from LEO.

Here is my scheme for propellent supply and propellent depots:
3VehiclesToMars.jpg


The blue boxes are supposed to be gas pumps indicating available propellent at those locations

The red vehicles need no wings, landing gear, ablation or thermal protection systems. Their delta V budget is less than earth's surface to LEO. I believe these could be made reusable as well as the green landers/ascent vehicles to moon and Mars.

The yellow vehicles may always be multi-stage expendables. But maybe not. There's skylon. There's also the possibility LEO propellent depots as well as momentum exchange tethers can reduce the minimum requirements enough that economical SSTO RLVs are doable.

An empty upper stage could be lofted to LEO. If it's tanks capacity is 3.8 km/sec worth of propellent, gassing up on lunar propellent could take it to EML1. At EML1 it could dock with another lunar propellent depot. From this location it would have a 2.4 km/sec advantage over LEO for any destination. Whether your goal is Venus, Mars, Phobos, or asteroids, a 2.4 km/sec advantage would be of enormous value.

A Later Edit: corrected some botched quote tags as well as typos
 
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orionrider

Guest
My view on the OP's question:

Asteroid mission close to Earth (<10 lunar distances):
Single short trip (<50days) with large delta and much propellant or long trip (3 to 6 month) with small delta and much life-support.
One large ship assembled in LEO from existing technology. Old ISS modules could even be recycled.
One propellant tank for the return trip to be sent in advance using a low delta-v (ion?) propulsion.
Price likely less than ISS: 70B$
Difficulty: medium;
Risk for the crew: medium (failure probability comparable to ISS, but no rescue possible).


Moon exploration:
Duration of several weeks for each mission.
At least 3 reusable Apollo-like ships to serve as transfer vehicles; Existing Soyuz technology.
3 reusable lunar landers; New design from scratch.
3 ascent stages; New design from scratch.
Walker suits, rovers, habitats, exploration tools, etc. New design from scratch.
Price likely comparable to Apollo: 170B$
Difficulty: high;
Risk for the crew: high (failure probability less than Shuttle, but cumulative with every mission).

Clearly, a 'one shot' asteroid mission would be both easier and less dangerous than several trips to the Moon.

President Obama'goal is more realistic and also less ambitious than the proposal of President Bush. Maybe it could be done if private companies or foreign agencies (China?) can be associated to the project.
With the construction of Space Station Bravo, the mid-life update of extended funding of Alpha in the timetable, I doubt the USA alone can support any of these missions.
 
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orionrider

Guest
List of known slow (<4km/sec relative) asteroids passing less than 10 lunar distances (LD) from earth in the period 2020 - 2030. Sorted by Delta-V.
Magnitude: mag 25 is about 30 meters, 20 is for a 300m object.


Name / Date / Distance / Delta-v / Magnitude

2000 SG344 / 2028 / 7.4 LD / 2.03 / 24.8
2001 GP2 / 2020 / 3.1 LD / 2.49 / 26.9
2009 CV / 2029 / 7.4 LD / 3.35 / 24.3
2009 YR / 2030 / 4.7 LD / 3.43 / 28.0
2003 LN6 / 2026 / 3.6 LD / 3.98 / 24.5

Not much choice...

See: http://neo.jpl.nasa.gov/cgi-bin/neo_ca
 
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EarthlingX

Guest
That will probably change soon :

http://www.planetary.org : Progress on WISE's asteroid survey
May. 28, 2010 | 06:05 PDT | 13:05 UTC

By Emily Lakdawalla

I wrote some time ago (last August, to be precise), about the expectations for the Wide-field Infrared Survey Explorer (WISE)'s contributions to solar system science. A couple of days ago, JPL posted an image and movie documenting the progress to date. Here's the plot:


WISE's scan of 50% of the sky for asteroids and comets
This image shows asteroids observed as of May 24, 2010, by NASA's Wide-field Infrared Survey Explorer, or WISE. As WISE scans the sky from its polar orbit, more and more asteroids and comets are caught in its infrared vision. The mission had surveyed about three-fourths of the sky to date; however, data for only about 50 percent of the sky had been processed for asteroids and comets. Credit: NASA / JPL-Caltech / UCLA / JHU

As of May 24, 2010, WISE had seen more than 60,000 asteroids. Of those, 11,000 were new! Think about that -- more than one in six of the asteroids seen in WISE images had not been noticed before by Earth-bound observers. In addition, WISE had also observed more than 70 comets, 12 of which were new, and about 200 near-Earth objects, more than 50 of which were new.

WISE Mission Thread; Launched Dec 14

JAXA chose Itokawa in the last stages of the Hayabusa mission.

What are dV differences from EML1 to those asteroids ?

As for cooperation, i think it will be easy to find some common ground with Roscosmos and ESA, since both Perminov and Dordain indicated such possibility, JAXA will be ready too, and that is without the others - list could be long and include China, of course.
 
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EarthlingX

Guest
I tried search for Atens and these three came on top :

Object | Close-Approach Date | Miss Distance Nominal (LD/AU) | Miss Distance Minimum | V relative | V infinity | N sigma | H (mag)
-------------------------------------------------------------------------------------------------------------------------------------------
(2007 DD) _ 2010-Jun-17 21:09 ± 00:01 _ 33.3/0.0856 _ 33.3/0.0856 _ 2.25 _ 2.24 _ 2.03e+04 _ 25.8

(2010 LG61) _ 2010-Jun-21 18:49 ± 3 03:11 _ 25.6/0.0659 _ 0e+00/0.0e+00 _ 3.24 _ 3.23 _ 0.552 _ 24.0

(2007 CS5) _ 2010-Jun-24 02:17 ± 1 08:51 _ 22.5/0.0578 _ 14.6/0.0375 _ 3.42 _ 3.41 _ 1.58e+03 _ 24.5
-------------------------------------------------------------------------------------------------------------------------------------------

Link above should be directly to the results page.

They are not exactly around the corner, but how they compare to Phobos ? Answer is probably in inclination .. ?
 
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orionrider

Guest
Thanks EarthlingX. WISE is a great mission, I hope they will find something large, close and slow compatible with the launch window ;)

ESA will follow and so will the Russians. Add Brazil, Japan and smaller players and you have a mission that is both largely supported by the public and cheap enough for all parties. Way to go for the future.
The Chinese, maybe, but I think they have a private agenda and who knows how advanced they will be in 2030?
 
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rockett

Guest
I think there is a misperception that where the US goes, everyone else (other countries) will follow.
That is no longer necessarily the case. Since the discovery of water on the moon, the other players seem focused there, not asteroids or Mars. That said, I really can't see a lot of support for an asteroid mission, except maybe JAXA.

The other thing we have to deal with is the short-sightedness of our project funding system. I was once told by the head of a Japanese delegation at the SSC neither they nor the Europeans could be sure of any long term commitment by the US to large projects, our politicians were just too fickle. Because of that they are reluctant to become involved in a big way. We burned a lot of bridges in the scientific community when we cancelled the Super Conducting Super Collider. That's why we had a hard time getting involvement in the ISS and it was originally Space Station Freedom. We almost burned those bridges again with the plan to de-orbit in 2015.

So asteroid or moon mission, we are unlikely to find partners except maybe the Russians.
 
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