# Obama's asteroid goal: tougher, riskier than moon

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#### SpaceTas

##### Guest
The flexible path mission envisioned is to a near earth object, with a few days travel time there and back.

These objects are small; less than a km across. So the surface gravity is very low. For a 1 km object with the density of Phobos (1.9 g.cm^3) the escape velocity is only 0.515 m/s (1.8 km/h 1.15 mi/hr) ie a fast walking pace. This is the speed needed to jump 0.0135m on Earth (lifting body's center of mass 1.3 cm == a little bit over an inch). This is easy. So the astronauts will have trouble moving about: maybe a shuffle rather than a moonwalk ! Manned Maneuvering Units, tethers and anchors will be needed. All this gear has already been used on Mir, Soyuz, Shuttle or ISS.

So an asteroid mission is like docking to a tumbling dirty station with no ready built hand rails. The advantage is no lander needed; "just" some grappling system. There will be some "fancy flying" needed to match the rotation of the asteroid especially if it very irregular in shape; eg if you land in a saddle you'll feel the gravity force from below and the sides of the saddle. Doable; ie NEAR and Hayabusa.

The energy/time needed to reach asteroid and return depends a lot on the asteroid's orbit and the capabilities of the spacecraft. The best would be an asteroid with an orbit closely matching (similar inclination and period) that of the Earth.
The current designs are skewed toward a lunar mission; which only requires 2 weeks (max) duration and the fuel for the Moon and back. So this would severely limit your options.

Here's a question for MeteorWayne: How many NEO's are know with inclinations < 10 deg and periods within 10% of 1 year.?

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#### SpaceTas

##### Guest
I don't think this mission is riskier or tougher than a lunar one. Docking with an asteroid has already been done by unmanned craft, and dodging boulders etc would be easier because of the much lower gravity. The touted dangers of moving around on an asteroid are like those for the ISS (bring pitons). NASA will need to develop longer duration exploration vehicle than for a lunar mission, but life support etc is already done in spades for the ISS.

This is the easiest, cheapest option.

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#### edkyle99

##### Guest
EarthlingX":12aincab said:

Yes, NASA will need a lander to land on the Moon, a big ticket schedule-pacing item, but if it doesn't have to spend money developing super heavy launch vehicles, the Agency is more likely to be able to afford lander development. Lander development will probably have to wait until after crew launch development is finished mid-decade so as not to bust the budget.

Once a slo-rate landing mission program is underway, fewer landings should mean less lander money required in any budget cycle.

- Ed Kyle

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#### aaron38

##### Guest
edkyle99":3qqug4o6 said:
Yes, NASA will need a lander to land on the Moon, a big ticket schedule-pacing item, but if it doesn't have to spend money developing super heavy launch vehicles, the Agency is more likely to be able to afford lander development.

And how do you get the lander to the moon without a heavy lift vehicle? The Altair lunar lander baseline mass is 37mT. To get that much mass into Lunar orbit using chemical propulsion requires 100mT of mass in LEO. Are we going to launch each lunar lander in 5 pieces and assemble them in orbit? Actually, make it 6 or 7 launches to cover the additional hardware and fuel for LEO docking operations.

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#### aaron38

##### Guest
JonClarke":1ipkfghu said:
aaron38":1ipkfghu said:
You don't need a reactor to visit an asteroid.

You're going to dock to a randomly rotating and tumbling rock and plan to track the sun with solar panels how exactly?

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#### Couerl

##### Guest
So we go to an asteroid, or the moon, or anywhere else and do some study and come back home.. I don't see how much more can be gained by sending people rather than probes to an asteroid other than to feed ego's. Scientifically there's not enough to be gained in my opinion and many, many more one-way trips could be funded to more interesting places than some big, expensive 2-way trip.

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#### edkyle99

##### Guest
aaron38":n2drx272 said:
edkyle99":n2drx272 said:
Yes, NASA will need a lander to land on the Moon, a big ticket schedule-pacing item, but if it doesn't have to spend money developing super heavy launch vehicles, the Agency is more likely to be able to afford lander development.

And how do you get the lander to the moon without a heavy lift vehicle? The Altair lunar lander baseline mass is 37mT. To get that much mass into Lunar orbit using chemical propulsion requires 100mT of mass in LEO. Are we going to launch each lunar lander in 5 pieces and assemble them in orbit? Actually, make it 6 or 7 launches to cover the additional hardware and fuel for LEO docking operations.

First, I'm not suggesting using Altair, or flying a Constellation mission. http://www.spacelaunchreport.com/moonslo.html Less aggressive missions could use a smaller, less-costly lander. Apollo's LM only weighed about 15 tonnes (but, of course, LM didn't do the lunar insertion burn assigned to Altair). Also remember that a big chunk of the Altair mass that you mention is actually propellant assigned to do the lunar orbit insertion burn, meaning that the Altair lunar orbiting mass is less than 37 tonnes or 45 tonnes or whatever it ended up being.

The majority of the lunar lander mass is propellant, which can be transported and transferred. The lander dry mass (probably 14 tonnes or less even for Altair) can easily be handled with one EELV Heavy, allowing it to be partially loaded with propellant when delivered to orbit. It "tops off" propellant in LEO. Alternatively, the mission could be designed to work with a lander that weighs 27 tonnes or less fully fueled in LEO (either reassigning the insertion burn or dramatically reducing the lander weight), allowing it to be carried on a single EELV Heavy launch.

NASA said it would take seven EELV Heavies to lift a Constellation mission to LEO. I expect this more modest proposal to take six, which could be spread out over many months so that they could all fly from a single, already-existing launch pad.

I am acknowledging that NASA doesn't have the money for an Atlair or a Constellation and proposing a more modest, hopefully affordable effort. Of course this more modest, slow-rate plan can't do everything that Constellation could do, but neither is Constellation going to achieve its agressive goals - Constellation is gone. Something, even a modest landing program, would be better than not returning to the Moon at all, ever, which is the current plan.

- Ed Kyle

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#### rockett

##### Guest
Obama is doing nothing more than passing the buck. He knows that after his Administration, there will likely be yet another grand scheme to go somewhere, that's why all the projections are far off in the future. He simply doesn't want to deal with it, or the the political fallout. This "non-plan" is simply a way out, without being held responsible.

It really isn't a matter of technology, we've had it for years. Here's a plan dating back to the early 90's for going back to the moon, that is quite workable and inexpensive, using mostly what we have. We could very easily use it as a starting point to a more permanent solution, investigate lunar ice, and so on.
http://www.nss.org/settlement/moon/ELA.html

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#### trailrider

##### Guest
BrianBoru":28k97axo said:
pathfinder_01":28k97axo said:
BrianBoru":28k97axo said:
Yup, lander development will be a total wast of time. Absolute no vision of landing on another planet justifies that conclusion.

The trouble is a lander is something that comes second to the ability to get there and stay there. Being able to spend months in deep space is more impresive than being able to land people for a mere two weeks. In addition a lander could be developed latter.

I was thinking in my head, and not clarifying in my post.
I was thinking about the -no-plan, of orbiting Mars in the 2030's. You go all that way, risking the lives of astronauts, to what? Re-enact Apollo 8, only after their 10 or so orbits, have them on a 3 - 6 month return, with what being the mission?
Sending basically chimps - they are not much more than spam in a can, because they won't even have the ability to land - and learning what exactly? There is absolutely no point whatsoever to sending humans on what amounts to Christopher Columbus or Leif Erikson sailing parallel to the North American coastline, looking at it in his spyglass, then turning around and going home.
As far as a lander being developed later, later than what? Another 10 - 20 years after the first human orbit of Mars?
I think that is an epic, ill conceived, visionless and bankrupt non-plan, as is possible to offer after a year-long study.
Also I add, that this malaise spans the last quarter century of the American civilian space agency, with equally culpable administrations and congresses.

Obama seems not to understand that there is one set of laws that even "his" Congress cannot override...Kepler's laws of planetary motion! It absolutely makes no sense to send astronauts to orbit Mars and then have them have to wait in orbit until the planets align again to permit return. Oh, of course, accoording to him we will by the "2030's" have developed "advanced propulsion systems" which will enable us to zip around the solar system like kids on a skate board! What we would gain by orbiting the Moon or Mars without landing, that robotic problem can't do, I don't know. It takes humans to exploit exploration opportunities! Give me a shovel and get me to the surface of Mars, and I (or any other person) could get Spirit unstuck in about 15 minutes or less!

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#### JonClarke

##### Guest
trailrider":3kudhyo4 said:
Obama seems not to understand that there is one set of laws that even "his" Congress cannot override...Kepler's laws of planetary motion! It absolutely makes no sense to send astronauts to orbit Mars and then have them have to wait in orbit until the planets align again to permit return. Oh, of course, accoording to him we will by the "2030's" have developed "advanced propulsion systems" which will enable us to zip around the solar system like kids on a skate board! What we would gain by orbiting the Moon or Mars without landing, that robotic problem can't do, I don't know. It takes humans to exploit exploration opportunities! Give me a shovel and get me to the surface of Mars, and I (or any other person) could get Spirit unstuck in about 15 minutes or less!

There is a lot that astronauts can do from Mars orbit that may well justify orbital missions. I have already pointed this out. Phobos, Deimos, teleoperation in real time of equipment on the surface, establishing of orbital havens, validation of aerocapture technologies, recovery of old spacecraft.

It's not how I would do it, but it is one valid approach among many.

H

#### HopDavid

##### Guest
SpeedRunner":2qfvlbfp said:
The asteroid mission has really caught my interest. It does indeed seem to be something very hard to do. One question is, how would they be able to get on the right trajectory and speed to meet up with an asteroid, and then be able to reverse course back to Earth? That in itself seems very challenging.

I was having a difficult time imagining manned trips to asteroids with reasonable time/reasonable delta V. I could think of quick trips with horrendous delta V, and I was able to imagine trips with a 7 month Hohmann trip there but with a long wait for the launch window home -- relatively little delta V but mission duration becomes a show stopper.

Then Isaac Kuo suggested a route to me. For an asteroid with an perihelion just over 1 A.U.:

"1) Transfer orbit toward NEO for about 90 days...angular speed is slower than Earth.

2) Dwell at the NEO for several weeks or months...angular speed is faster than Earth.

3) Transfer orbit back to Earth for about 90 days...angular speed is slower than Earth."

I drew a picture of this path:

There are two elliptical transfer orbits with a focus lieing on the sun's center. But they are hard to discern in this illustration since they are both nearly circular and ther vertexes are only 20 degrees apart. The transfer ellipses are in light grey except for the earth to asteroid section and the asteroid to earth section are heavier and in black.

For any given asteroid, such a opportune geometry would be a rare event. But given that there are many asteroids, such an opportunity might occur fairly often.

The two transfer ellipses are tangent to the asteroid's orbit. And they only cross the earth's orbit at a degree or two. Delta V required for changing direction would be minimal. Almost all the delta V would be changing speed, much like a Hohmann orbit.

My ballpark guesstimate: Such a mission would take 5 km/sec less than a lunar landing.

B

#### bdewoody

##### Guest
To me, going to the moon with the intent of establishing an eventual permanent base still makes way more sense. There are no known threats to earth from an asteroid in this century. By establishing a base on the moon we can send missions to asteroids that pose a possible threat to earth with a much smaller vehicle than would be necessary launching from earth.

As I have said before the moon should be our space station. It has the raw materials to become self sufficient. Something the ISS or a base on an oversized rock can never do. There is a whole lot of difference between what NASA accomplished in the late 1960s and early 1970s and what should be done now. I hate that "been there done that" attitude that many people cop when talk of going back to the moon surfaces. From my point of view a manned orbit of Mars without landing is more of a been there done that scenario. What good will it do and what will it accomplish.

Once we are firmly established on the moon the rest of the solar system will be easy to reach.

It's sort of like trans pacific flight in the 1930's. Even though the goal of the airlines was Hong Kong they realised that first they had to be able to make it to Hawaii and Midway, establish bases there and then the rest of the Pacific rim was in reach.

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#### scottb50

##### Guest
bdewoody":cgxiab49 said:
There are no known threats to earth from an asteroid in this century.

That we know of, yet.

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#### rockett

##### Guest
scottb50":f0oeo3ke said:
bdewoody":f0oeo3ke said:
There are no known threats to earth from an asteroid in this century.

That we know of, yet.

There are a number of near misses on the board though, it wouldn't take much to perturb one into a hit...

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#### Couerl

##### Guest
Public interest will never care about going to a rock, but if we find an earth-like planet in the true sense anywhere close by (Say <100 ly's) then interest and funding for space missions will go through the roof and then you can go to your stupid rock all you want and dance and sing and wave flags and take core samples because by then something genuinly interesting will be going on. :geek:

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#### neutrino78x

##### Guest
rockett":308zv7re said:
Obama is doing nothing more than passing the buck. He knows that after his Administration, there will likely be yet another grand scheme to go somewhere, that's why all the projections are far off in the future. He simply doesn't want to deal with it, or the the political fallout. This "non-plan" is simply a way out, without being held responsible.

Perhaps, but you're really missing the point of the Obama plan. The idea behind the Obama plan is that there are going to be many, many more people in Earth orbit, and most of them will go up on privately owned rockets. There will be people going into space once a week at least, if not more often.

NASA, under Obama plan, steps aside and lets the Merchants commercialize space the way the Sea was commercialized.

Yes, NASA will occasionally do human space flight missions, but the majority of the US Space Program will be Private Enterprise.

The idea here is that the era of NASA doing all or most US human space flight is over. US Space activity is by no means over, it is just US Government manned space that is being scaled back.

The Queen Mary 2 is a British ship, flying the flag of the United Kingdom, and subject to the orders of Her Majesty the Queen of Britain in time of war, but she is not owned or operated by Her Majesty's Government. Yet, no one says "the Queen Mary 2 is not a British ship, because she is not called HMS Queen Mary 2". That's how it normally works on the sea. Most ships are not from the Government. That's how it should work in space also.

Notice the US Flag on the Falcon 9 rocket:

That's an American rocket. Just because it is not NASA or US Armed Forces does not mean it is not an American rocket.

--Brian

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#### edkyle99

##### Guest
neutrino78x":3im5b7st said:
. The idea behind the Obama plan is that there are going to be many, many more people in Earth orbit, and most of them will go up on privately owned rockets. There will be people going into space once a week at least, if not more often.

NASA, under Obama plan, steps aside and lets the Merchants commercialize space the way the Sea was commercialized.

Yes, NASA will occasionally do human space flight missions, but the majority of the US Space Program will be Private Enterprise.

Obama's plan funds a commercial human launch effort for ISS support. That amounts to only perhaps two to four crewed orbital flights per year.

Commercial orbital flight is possible right now, but no one is doing it in the United States. If anything, Obama's plan makes it *less* likely that companies will try to survive on "tourist" flights, since they will be able to gorge on government money instead.

If you don't believe me, look at "commercial" unmanned flight. The number of U.S. commercial orbital launches has declined, not increased, since the work was transferred from NASA after the loss of Challenger.

- Ed Kyle

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#### neutrino78x

##### Guest
edkyle99":knq0jn5e said:
Obama's plan funds a commercial human launch effort for ISS support. That amounts to only perhaps two to four crewed orbital flights per year.

Yes, and that funding will make tourist, rapid transoceanic, and other flights more frequent. Just as the Airmail program advanced commercial aviation.

If you don't believe me, look at "commercial" unmanned flight. The number of U.S. commercial orbital launches has declined, not increased, since the work was transferred from NASA after the loss of Challenger.

SpaceX's manned space contract will enable them to fly more often, eventually launching Bigelow's manned space station, which will require more manned space flights.

If all goes well, this President will be remembered for putting NASA on the correct path and greatly enhancing the US space program.

--Brian

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#### bdewoody

##### Guest
Couerl":6esuauaw said:
Public interest will never care about going to a rock, but if we find an earth-like planet in the true sense anywhere close by (Say <100 ly's) then interest and funding for space missions will go through the roof and then you can go to your stupid rock all you want and dance and sing and wave flags and take core samples because by then something genuinly interesting will be going on. :geek:
Unless the earthlike planet is within 5-10 LY any trips to said planet are so far in the future that our great-great-great- grandchildren might be able to make the trip. We won't be leaving this solar system for the foreseeable future.

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#### edkyle99

##### Guest
neutrino78x":1a23tnmz said:
SpaceX's manned space contract will enable them to fly more often, eventually launching Bigelow's manned space station, which will require more manned space flights.

SpaceX does not have a "manned space contract". It has an ISS cargo contract, and it has a long way to go before it achieves even that goal.

When NASA finally asks for human launch bidders, SpaceX, if it bids, will not be the only bidder. If it bids, it may not win. Its competitors will likely offer the proven Atlas V, which can lift a few tonnes more mass to LEO than the unproven Falcon 9 (especially the Block 1 Falcon 9 currently available). NASA has already propped up one potential bidder by giving it the Crew Rescue Vehicle work.

- Ed Kyle

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#### edkyle99

##### Guest
neutrino78x":4r3z3lbp said:
edkyle99":4r3z3lbp said:
Obama's plan funds a commercial human launch effort for ISS support. That amounts to only perhaps two to four crewed orbital flights per year.

Yes, and that funding will make tourist, rapid transoceanic, and other flights more frequent. Just as the Airmail program advanced commercial aviation.

Not enough mail in space to support this type of comparison!

- Ed Kyle

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#### scottb50

##### Guest
Couerl":hzs2h5he said:
Public interest will never care about going to a rock, but if we find an earth-like planet in the true sense anywhere close by (Say <100 ly's) then interest and funding for space missions will go through the roof and then you can go to your stupid rock all you want and dance and sing and wave flags and take core samples because by then something genuinly interesting will be going on. :geek:

Until we discover Warp Drive even 100ly's is insurmountable. Maybe Roddenberry was right, until someone finds us and shares the technology we are stuck. In the mean time there are places to go and things to see and who knows what we will find or find out. Columbus was looking for a quicker way to India and he stumbled upon what has become the predominate area of the World. Could the Wright brothers have envisioned the 747 or the SR71? Sometimes all it takes is a spark to ignite amazing things.

I look at it more that we have more then proved we can live and work in LEO and that we can reach and explore the moon, Mars, other objects orbiting the Sun and even some orbiting other Planets. In a lot of cases manned exploration might be too much of a challenge, at least now, but in others it might make a huge difference. Mars would be a good example, a manned mission could have explored vastly greater area then the Rovers have and on the spot modifications of tests and such could provide huge amounts of data.

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#### Couerl

##### Guest
bdewoody":37th1t4v said:
Unless the earthlike planet is within 5-10 LY any trips to said planet are so far in the future that our great-great-great- grandchildren might be able to make the trip. We won't be leaving this solar system for the foreseeable future.

Hi bdwoody, even if the said planet was one ly (impossible, but irrelevant) away those trips wouldn't happen and probably wouldn't happen for our great, great grandchildren either, but that is not my point. My point is that if we can simply nail down an "earth-like" (in the truest sense) planet anywhere close by (<100 ly's) it will light an unprecedented fire for space exploration and development. The idea that we'll never get to go there doesn't matter, we'll at least have a reason to actually TRY. Right now, your typical Droid (newest cell phone/Ipod gadget or whatever) gets more R&D and marketing money than all of space research put together. That in my mind is a crime against our great and noble species.

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#### Couerl

##### Guest
scottb50":2ye3j9bk said:
Sometimes all it takes is a spark to ignite amazing things..

That is right and that spark is not a barren and irrelevant asteroid, but rather a relatively close and (hopefully) empty earth-like planet just waiting to be exploited for all of its riches. More episodes of raising the flag on an empty and inhospitable world/rock will doom public interest and thus funding for manned space flight altogether and possibly for good.

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#### rockett

##### Guest
Couerl":szhrnvdq said:
bdewoody":szhrnvdq said:
Unless the earthlike planet is within 5-10 LY any trips to said planet are so far in the future that our great-great-great- grandchildren might be able to make the trip. We won't be leaving this solar system for the foreseeable future.

Hi bdwoody, even if the said planet was one ly (impossible, but irrelevant) away those trips wouldn't happen and probably wouldn't happen for our great, great grandchildren either, but that is not my point. My point is that if we can simply nail down an "earth-like" (in the truest sense) planet anywhere close by (<100 ly's) it will light an unprecedented fire for space exploration and development. The idea that we'll never get to go there doesn't matter, we'll at least have a reason to actually TRY. Right now, your typical Droid (newest cell phone/Ipod gadget or whatever) gets more R&D and marketing money than all of space research put together. That in my mind is a crime against our great and noble species.
Amen to THAT! We spend billions of dollars on stuff that is obsolete "next year" every year...

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