# Moon, Mars, or Asteroid? Which is the best goal?

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## What should be NASA's next goal?

• ### Mars mission. We need to move on.

• Total voters
39
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R

#### rockett

##### Guest
EarthlingX":30ripfvf said:
100m asteroid would have mass about 1 million tons, assuming 2kg/l density. I wouldn't worry much about yanking it of the course as an accident.

Wiki : Gravity tractor - example for 100m asteroid, 1 cm ΔV in 10 years
Uh, EarthlingX, I think your math is a bit off (please check and let me know if my figures are incorrect). Using the density you provided and assuming a sphere (which it seems most asteroids are not), I get the following:

volume= 4/3 pi r^3
m=dv

That would yield the following mass estimates for the known mission candidates (http://www.space.com/news/nasa-space-asteroid-mission-near-earth-100831.html):

60m rock known as 2009 OS5 in 2020
226 mt

19.5m space rock 1999 AO10 in 2025
7.2 mt

100m 2003 SM84 in 2045
1154 mt

All are considerably less than the 1 million tons you mentioned.

In addition the figures for the plain vanilla Orion capsule are:
8,913 kg 8.9 mt
w/svc module: 21.25 mt

Considering the mass of the Orion + Service module, it is quite possible that the orbits of 2009 OS5 and 1999 AO10 could be perturbed, I would think. Also my mass calculations could be quite a bit on the "heavy" side, if the shape is closer to the "potato" that many pictures of asteroids show.

E

#### EarthlingX

##### Guest
Ok, one more time, very slow, 100 m asteroid, 2 kg/dm^3, or 2 t/m^3

V=r^3*pi*4/3 = 50^3 * pi * 4/3 = (125 000 * pi * 4/3) m^3 = 523 598,78 m^3

523 598,78 m^3 * 2t/m^3 = 1 047 197,55 t

Anything wrong ?

btw, doesn't strike you as a bit odd to have 20m asteroid weigh only 17t ? If it would be just a line, made out of cubes, 1m at the side, with 2 t/m^3, it would be 40t ..

V=r^3*pi*4/3 = 10^3*pi*4/3 = (1 000 * pi * 4/3) m^3 = 4188,8 m^3

4188,8 m^3 * 2t/m^3 = 8377,58 t

Can you show how did you get your numbers ?

Here's a bit of help for this complicated computations :

http://www.abe.msstate.edu : ABE Volume Calculator - Calculate volume of sphere

R

#### rockett

##### Guest
EarthlingX":197s50br said:
Ok, one more time, very slow, 100 m asteroid, 2 kg/dm^3, or 2 t/m^3

V=r^3*pi*4/3 = 50^3 * pi * 4/3 = (125 000 * pi * 4/3) m^3 = 523 598,78 m^3

523 598,78 m^3 * 2t/m^3 = 1 047 197,55 t

Anything wrong ?

btw, doesn't strike you as a bit odd to have 20m asteroid weigh only 17t ? If it would be just a line, made out of cubes, 1m at the side, with 2 t/m^3, it would be 40t ..

V=r^3*pi*4/3 = 10^3*pi*4/3 = (1 000 * pi * 4/3) m^3 = 4188,8 m^3

4188,8 m^3 * 2t/m^3 = 8377,58 t

Can you show how did you get your numbers ?

Here's a bit of help for this complicated computations :

http://www.abe.msstate.edu : ABE Volume Calculator - Calculate volume of sphere

Sorry, you are right. I added a conversion to mt after the fact. It should be (I think):
60m rock known as 2009 OS5 in 2020
226,000 mt

19.5m space rock 1999 AO10 in 2025
7,200 mt

100m 2003 SM84 in 2045
1,154,000 mt

O

#### oldAtlas_Eguy

##### Guest
It does not take a large delta V difference to make a large time on target position difference after a year. A 6m/s delta V produces a 200,000km position difference after one year from the original orbit. A 200,000km difference is enough to create an Earth direct hit by NEO that comes as close as 100,000km. After 10 years a 0.6m/s delta V change can produce the same error. That’s 1.3 MPH! Just a bump on a 20m asteroid by a vehicle that is 1/20th the weight going 20MPH.

E

#### EarthlingX

##### Guest
Current plans are much more modest. They don't talk about ΔV in the range of meters, but centimetres. Time-frame is larger, of course, but the idea is more or less something along the line you are suggesting.

http://www.universetoday.com : How to Deflect an Asteroid with Today’s Technology
...
In a phone interview, Schweickart described two types of “deflection campaigns” for a threatening asteroid: a kinetic impact would roughly “push” the asteroid into a different orbit, and a gravity tractor would “tug slowly” on the asteroid to precisely “trim” the resultant change course by using nothing more than the gravitational attraction between the two bodies. Together these two methods comprise a deflection campaign.
...

That is about deflection, which would then lead to relocation. With such technology under belt, all sorts of sci-fi scenarios become sci.

oldAtlas_Eguy":1yam5opt said:
Just a bump on a 20m asteroid by a vehicle that is 1/20th the weight going 20MPH.
20 m asteroid, with assumed density of 2 kg/l would have about 8400 t of mass, 1/20 = 418,9 t.

Bit heavier than what is on the table ..

R

#### rockett

##### Guest
Sad to say, more water found than expected. It's really a shame that we have an Administration that just wants to put their own stamp on human space flight (or it appears, really would rather ignore it altogether).

Moon Crater Has More Water Than Parts of Earth
Water ice makes up about 5.6 percent of the total mass on the floor of Cabeus — making the crater about twice as wet as Sahara Desert soil, according to LCROSS mission principal investigator Tony Colaprete.

"That is a surprise," said Colaprete, who works at NASA's Ames Research Center in Moffett Field, Calif. "And it has a lot of ramifications in terms of our understanding of water and other volatiles on the moon."
http://www.space.com/scienceastronomy/moon-cabeus-crater-water-101021.html

Moon crash splashed up some surprises
Mission chief scientist Anthony Colaprete of the NASA Ames Research Center calculates there could be 1 billion gallons of water in the crater that was hit — enough to fill 1,500 Olympic-sized swimming pools.

"Where we impacted was quite wet," Colaprete said, adding there could be more such craters at both the moon's poles.

Proof that the moon is dynamic and not a dry, desolate world offers hope for a possible future astronaut outpost where water on site could be used for drinking or making rocket fuel.

But the scientists' excitement is tempered by the political reality that there's no plan to land on the moon anytime soon.

Given the recent water find, "it's disappointing that we're not going to forge ahead" with a moon return next decade, said space scientist Greg Delory of the University of California, Berkeley, who was not involved in the project.
http://www.msnbc.msn.com/id/39781265/ns/technology_and_science/

Video:
http://www.msnbc.msn.com/id/32545640

R

#### rockett

##### Guest
oldAtlas_Eguy":jfum8c2l said:
It does not take a large delta V difference to make a large time on target position difference after a year. A 6m/s delta V produces a 200,000km position difference after one year from the original orbit. A 200,000km difference is enough to create an Earth direct hit by NEO that comes as close as 100,000km. After 10 years a 0.6m/s delta V change can produce the same error. That’s 1.3 MPH! Just a bump on a 20m asteroid by a vehicle that is 1/20th the weight going 20MPH.
I agree with you that an asteroid mission to one of the smaller rocks without more detailed information could be dangerous, if not downright reckless. The pronouncements about such a mission are being made as if the objects were planets and not much less massive and potentially more sensitive in their orbits.

“It doesn’t have to be real big, but bigger gets the job done a little faster. The feature you are interested in the outset is not the gravity tractor but the transponder that flies in formation with the asteroid and you track the NEO, and back on Earth we can know exactly where it is.”

Schweickart said even from ground tracking, we couldn’t get as precise an orbit determination of an NEO as we could by sending a spacecraft to the object. Additionally, generally speaking, we may not know when we send an observer spacecraft what action will be required; whether an impact will be required or if we could rely on the gravity tractor.

http://www.universetoday.com/75816/how-to-deflect-an-asteroid-with-today’s-technology/

O

#### oldAtlas_Eguy

##### Guest
Maybe NASA is hopping that they do an asteroid mission to a small rock that then has its orbit changed causing a massive funding increase to then do follow-on missions for a permanent asteroid deflection capability.

R

#### rockett

##### Guest
oldAtlas_Eguy":1vrtjv7v said:
Maybe NASA is hopping that they do an asteroid mission to a small rock that then has its orbit changed causing a massive funding increase to then do follow-on missions for a permanent asteroid deflection capability.
THAT would be the "OOPS!" of the century! Probably result in all kinds of international tensions, depending on where it was projected to hit. Results would not be too different (depending on the size of the rock) from those described in Robert A. Heinlein's "The Moon Is a Harsh Mistress" (http://en.wikipedia.org/wiki/The_Moon_Is_a_Harsh_Mistress, 1966)...

R

#### rockett

##### Guest
Well lunies, it looks like the experts agree! When it comes to exploiting space resources, a panel of experts at the Space Studies Institute (http://ssi.org/), expects that the moon is the best candidate to exploit natural resources.

This clearly runs contrary to the Obama Administration's direction. Let's hope the scientists, engineers, and common sense prevail.

http://www.space.com/news/moon-mining-space-exploration-101030.html
The moon won out over asteroids and Mars, chiefly because it's so close to Earth and has so much water, as well as other resources like methane and ammonia.

"I think the moon is clearly the answer," said Greg Baiden, chief technology officer of Penguin Automated Systems, a robotic technology firm. "I could easily make a business case for going to the moon."

Baiden spoke during a session here yesterday (Oct. 29) at a conference called Space Manufacturing 14: Critical Technologies for Space Settlement. The meeting is organized by the non-profit Space Studies Institute.

Private enterprise, Baiden and others said, will likely lead the way to mining the moon because there's so much money to be made, but it will probably need government to prime the pump.

In this article it also mentioned a private company to do it:
Texas Firm Draws up Plans for Orbital Gas Station
http://www.space.com/news/070314_moon_fuelingstation.html

O

#### oldAtlas_Eguy

##### Guest
First step a fueling depot in LEO. It is much easier to ship water to LEO than LOX and LH2. A depot that can produce LOX and LH2 and store it from water would be an asset to any space operations. Later the water can be supplied from the Moon instead of being shipped up from Earth. This would demonstrate a demand for space water. Which could then spur investments in other additional infrastructure to mine Lunar water and deliver it back to LEO.

C

#### csmyth3025

##### Guest
oldAtlas_Eguy":1ow372gp said:
First step a fueling depot in LEO. It is much easier to ship water to LEO than LOX and LH2. A depot that can produce LOX and LH2 and store it from water would be an asset to any space operations. Later the water can be supplied from the Moon instead of being shipped up from Earth. This would demonstrate a demand for space water. Which could then spur investments in other additional infrastructure to mine Lunar water and deliver it back to LEO.
I agree 100%.

Chris

S

#### SJQ

##### Guest
If you were to launch water into LEO, would it be better to do so as a liquid or a solid mass? Liquid gets you a little more mass per unit volume (cool the payload to 4°C for maximum density?). Ice sacrifices some mass per unit volume, but its relative rigidity might make the payload structure simpler/lighter. Aside from a water-tight container, it might be the payload structure. Once in orbit, there's plenty of time to melt the payload.

B

#### bdewoody

##### Guest
I still think that Obama knew exactly what he was doing when he put forth the asteroid challenge and then NASA stupidly bought it. No new manned space craft during the Obama administration so he could divert the funds elsewhere and by the time the rest of us found out the asteroid mission was a waste of time he would be long out of office.

C

#### csmyth3025

##### Guest
SJQ":1otusmoj said:
If you were to launch water into LEO, would it be better to do so as a liquid or a solid mass? Liquid gets you a little more mass per unit volume (cool the payload to 4°C for maximum density?). Ice sacrifices some mass per unit volume, but its relative rigidity might make the payload structure simpler/lighter. Aside from a water-tight container, it might be the payload structure. Once in orbit, there's plenty of time to melt the payload.
You've got a good question there. Certainly with all the LOX being pumped into the rocket on the launch pad, it would't take very much extra plumbing to pass some through the (water) payload. Once frozen to ~ -300 degrees F, it should remain solid through the ascent phase. Once in orbit there would be no "weight" on the walls of the payload container so I would think it could be, essentially, a fairing lined with a plastic bag. Do we have any rocket scientists here who can speak to the practicality of launching ice vs liquid water?

Chris

B

#### bdewoody

##### Guest
I think now with every new announcement from NASA about resources available on/in the moon that they walked away from the moon plan too soon. It seems pretty evident to me that without a doubt the moon holds the most promise for an off world base/colony to survive. It is doable with technology we already have or have in development and can be accomplished without breaking the bank, so to speak. Whether the USA through NASA goes it alone or an international space agency is organised to achieve the goal makes no difference to me. But once either NASA or the ISA is funded to start the process meddleing by government leaders needs to be stopped.

O

#### oldAtlas_Eguy

##### Guest
As other nations get closer to actually being able to possibly start developing the Moon’s resources I believe the US government will most likely wake up to the fact that if they don’t support US industry to develop Lunar resources they could be in the same position that they find themselves today of purchasing capability from another nation’s corporations, like purchasing rides to the ISS from the Russians. US government support of the commercial space industry is not even close to what it does for other industries like say the auto industry.

S

#### scottb50

##### Guest
oldAtlas_Eguy":19bjqi7y said:
As other nations get closer to actually being able to possibly start developing the Moon’s resources I believe the US government will most likely wake up to the fact that if they don’t support US industry to develop Lunar resources they could be in the same position that they find themselves today of purchasing capability from another nation’s corporations, like purchasing rides to the ISS from the Russians. US government support of the commercial space industry is not even close to what it does for other industries like say the auto industry.

While it's nice to think in the long-run the costs of developing resources should not be governments job. Exploration and research that leads the way has been the way since the 1930's with the knowledge passed on to industry. Everything from airfoil refinement to jet engines originated as government sponsored research and development, the 707 was a commercial development of the KC-135 and I doubt Spacex started with a clean sheet of paper.

That China and others are pushing for the moon is not significant either, they are no closer to being able to exploit the resources then we are. It would also be safe to say it is a waste of their resources mirroring U.S. and Soviet exploits from the 60's and 70's, sure it shows their capabilities but only in copying what others did and using data freely available.

Visiting asteroids would prove designs and equipment for longer range Mars missions and vastly expand our knowledge of such objects, including whether there is a commercial reason to go there. The data is pretty much there about the moon, it has been mapped extensively, landed on or crashed into repeatedly and occupied for various durations. Now it's a matter of is it worth going there commercially and so far the answer is no. Asteroids and Mars are the next logical steps for manned exploration, maybe more will be found to exploit to attract commercialization there.

Right now LEO is still questionable for commercial exploitation, if the uses and costs allow creater commercial use that could branch out to the moon, asteroids or Mars but as of now it just isn't there.

C

#### csmyth3025

##### Guest
scottb50":vp9piv0g said:
...The data is pretty much there about the moon, it has been mapped extensively, landed on or crashed into repeatedly and occupied for various durations. Now it's a matter of is it worth going there commercially and so far the answer is no. Asteroids and Mars are the next logical steps for manned exploration, maybe more will be found to exploit to attract commercialization there.

Right now LEO is still questionable for commercial exploitation, if the uses and costs allow creater commercial use that could branch out to the moon, asteroids or Mars but as of now it just isn't there.
I would say that there's increasing evidence that there are resources on the Moon (particularly the Lunar poles) that are commercially exploitable. As a first step, extracting water from the Moon may be much more feasble than doing so from NEA's. Once there is a robust space infrastructure in place this may change.

Infrastructure in LEO is, to me, the jumping off point for space travel. Similar to the airports that provide air travel to distant destinations. Getting to LEO is a monumental task. Stations in LEO can, hopefully, provide the assembly and fueling services needed to construct and operate ships that will be able to take people to higher orbit space colonies and, perhaps, colonines on Mars.

Chris

J

#### jonto2012

##### Guest
Love seeing 70% in favor of the moon, yes! Just wonder if it reflects the nation's views, or at least the space community's views. Maybe the lunar goal will come back into NASA's plans after all.

A

#### actionjack39

##### Guest
I live in Oklahoma and At midnight in the S.W. at Approx 40 degrees what planet am I seeing?

M

#### MeteorWayne

##### Guest
Questions like this belong in the "Ask the Astronomer" forum, not this one. Please look for the correct forum before asking a question.

Welcome to Space.com

Wayne

R

#### rockett

##### Guest
scottb50":1k0pamt4 said:
While it's nice to think in the long-run the costs of developing resources should not be governments job. Exploration and research that leads the way has been the way since the 1930's with the knowledge passed on to industry. Everything from airfoil refinement to jet engines originated as government sponsored research and development, the 707 was a commercial development of the KC-135 and I doubt Spacex started with a clean sheet of paper.

That China and others are pushing for the moon is not significant either, they are no closer to being able to exploit the resources then we are. It would also be safe to say it is a waste of their resources mirroring U.S. and Soviet exploits from the 60's and 70's, sure it shows their capabilities but only in copying what others did and using data freely available.

Visiting asteroids would prove designs and equipment for longer range Mars missions and vastly expand our knowledge of such objects, including whether there is a commercial reason to go there. The data is pretty much there about the moon, it has been mapped extensively, landed on or crashed into repeatedly and occupied for various durations. Now it's a matter of is it worth going there commercially and so far the answer is no. Asteroids and Mars are the next logical steps for manned exploration, maybe more will be found to exploit to attract commercialization there.

Right now LEO is still questionable for commercial exploitation, if the uses and costs allow creater commercial use that could branch out to the moon, asteroids or Mars but as of now it just isn't there.
Space Studies Institute seems to disagree with you, Scott. See my earlier post or : http://www.space.com/news/moon-mining-space-exploration-101030.html

N

#### neilsox

##### Guest
If I understood Rush Limbaugh correctly = unlikely: Someone speaking for the Liberals, or perhaps the Obama administration, proposed that we send 2 pairs of elderly humans (in separate space craft) one way to Mars about 2030. This has the advantage that one way may be less than half as costly as a round trip, so we can get space colonization going sooner.
In my opinion, elderly is wrong; it should be two females age about 25 and 35 plus a sperm bank and embryo bank. That way Mars can be colonized without any trips after the first two. What do you think? Neil

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