The more I read and think about our President's stated goal of sending a manned mission to an asteroid the more I question why. Is it just a diversion so he can eventually scrap the USA's manned space program? What could a manned mission to an asteroid accomplish that a robotic mission couldn't? Does he want to send astronauts to a mainstream asteroid that stays between Mars and Jupiter or a NEO that has a highly eliptical orbit. To me a manned asteroid mission falls under the publicity stunt category and has no long term benefit
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I would be happy to see us go anywhere. And I don't think sending humans to an asteroid, or anywhere else in space, is a waste of time.
And we better keep at it, otherwise we will lose our know-how.
And we better keep at it, otherwise we will lose our know-how.
Sending people to a nearby asteroid is not a publicity stunt and it is not necessary for Science either.
But it is good training for a longer mission: travel some, rendezvous, match velocities, orbit, land, explore a bit and come back in one piece. Safer and cheaper than the Moon, perfect for practice.
Next time we go all the way to Mars and then beyond.
Baby steps, learn how to walk before you leap. Sounds like a good idea.
But it is good training for a longer mission: travel some, rendezvous, match velocities, orbit, land, explore a bit and come back in one piece. Safer and cheaper than the Moon, perfect for practice.
Next time we go all the way to Mars and then beyond.
Baby steps, learn how to walk before you leap. Sounds like a good idea.
I really doubt that executing a trip to an asteroid would be cheaper than going to the moon. I suppose the cost would be directly related to which asteroid was chosen. A trip to one of the main belt asteroids going beyond Mars would definitly be way more costly than going to the moon. A trip to one of the near earth passing asteroids would be closer than the others but the trajectory would be difficult to match and trickier to break away from and return to earth.orionrider":1dhirvoi said:Sending people to a nearby asteroid is not a publicity stunt and it is not necessary for Science either.
But it is good training for a longer mission: travel some, rendezvous, match velocities, orbit, land, explore a bit and come back in one piece. Safer and cheaper than the Moon, perfect for practice.
Next time we go all the way to Mars and then beyond.
Baby steps, learn how to walk before you leap. Sounds like a good idea.
The moon would be a much easier goal and many times safer.
well... i really think a return trip to the moon, would be kind of pointless... lets journey further
man landing on an asteroid for the 1st time ever, would be an incredible achievement. , and a large stepping stone, for a future manned mission to mars......
man landing on an asteroid for the 1st time ever, would be an incredible achievement. , and a large stepping stone, for a future manned mission to mars......
A single manned trip back to the moon would be pointless but that was not the plan. The plan was to with each successive mission to build a base on the moon from which other ventures both commercial and scientific could be started.Spaceman500":2uur5oz7 said:
On the other hand we could never build a base on a NEO asteroid. A manned mission to an asteroid is like an expedition to Mt. Everest, a brave adventure but of little other value. Some day when rich folks own their own space ships I can see expeditions to Ceres or Eros happening for the thrill of it.
Going to an asteroid provides little or no help in mounting an assault on Mars whereas building a base on the moon helps to develope the tools needed to stay on Mars for extended periods of time. Sending men to an asteroid just for a few hours or days is a collossal waste of money and resources regardless of the achievement.
Well, one thing we have to remember:
Of all the dangers we currently face, none is as difficult to overcome for us than the prospect of being smushed by a very large, very uncaring rock.
It would certainly be advisable to know a bit more about them.
Of all the dangers we currently face, none is as difficult to overcome for us than the prospect of being smushed by a very large, very uncaring rock.
It would certainly be advisable to know a bit more about them.
The Moon has gravity, which means you need to design and test a new lander with braking rockets, legs, high structural integrity and all that, plus an ascent stage. It would take many years and lots of €$.
Landing and taking off from a passing asteroid costs nothing more than reversing course in deep space. You can do it in the near future using an existing spacecraft and regular EVA suits. All you need is more propellant. In fact the mission would be very similar to servicing a satellite, but then not in Earth orbit. I'm sure there are enough Near Earth Asteroids to choose one that has a limited delta-v, so it doesn't cost too much.
It would be a useful test of hardware, navigation, deep space communications, EVA procedures, life support, etc.
The first time people leave Earth orbit. International mission, very symbolic, historical day, live on CNN, etc. :mrgreen:
And as 'a_lost_packet' said, it could even be useful...
Landing and taking off from a passing asteroid costs nothing more than reversing course in deep space. You can do it in the near future using an existing spacecraft and regular EVA suits. All you need is more propellant. In fact the mission would be very similar to servicing a satellite, but then not in Earth orbit. I'm sure there are enough Near Earth Asteroids to choose one that has a limited delta-v, so it doesn't cost too much.
It would be a useful test of hardware, navigation, deep space communications, EVA procedures, life support, etc.
The first time people leave Earth orbit. International mission, very symbolic, historical day, live on CNN, etc. :mrgreen:
And as 'a_lost_packet' said, it could even be useful...
I'm a huge advocate of Moon before Mars. That said, I'm not worried as I'm almost 100% certain the US is going to have to change its plans to send a flyby to Mars in the mid-2030s since over the next five to ten years the rest of the world (including perhaps a few private companies) is going to be happily exploring the Moon and I doubt the US will be happy to just sit on the sidelines and wait another decade or two just for a single manned flyby and return. The manned asteroid mission is a good idea IMO, not just because it's worth it to directly observe asteroids by a manned mission instead of a robotic probe for the first time ever, but because being new it might help to excite people about space again that otherwise wouldn't be. It's odd that so many are jaded about the Moon even though the majority of the people alive today don't even have a single memory of a manned mission there (including me), but somehow that's what happened.
A rover to the surface might be the best way to accomplish this. First of all it will be exciting to have images from the surface for the first time since the early 1970s, but it will also show just how easy it is to explore in comparison to Mars given the extremely short delay and long day. Set up shop somewhere near the south pole and you can essentially manually drive it around for about 20 days at a time. Compare that to Mars - waiting (at least) ten minutes to see the result of a command, planning for nightfall, having to find a good location to wait out the winter, much lower solar energy overall, etc. etc.
A rover to the surface might be the best way to accomplish this. First of all it will be exciting to have images from the surface for the first time since the early 1970s, but it will also show just how easy it is to explore in comparison to Mars given the extremely short delay and long day. Set up shop somewhere near the south pole and you can essentially manually drive it around for about 20 days at a time. Compare that to Mars - waiting (at least) ten minutes to see the result of a command, planning for nightfall, having to find a good location to wait out the winter, much lower solar energy overall, etc. etc.
I would hope that a manned landing on an asteroid has the contingency of remaining on the asteroid long term if death is the likely result of an attempt to return to Earth. We can add this contingency at relatively low cost with an unmanned supply rocket that arrives at the asteroid just before or just after the the manned craft. Humans can likely survive long term near the mass center of a small asteroid where radiation exposure is likely lower than typical at sealevel on Earth. It would be uncomfortable and boring, but the rescue attempt at the next close approach of the asteroid years later would be very stimulating to the space industry and would get massive public support, in my opinion. Some of the NEO = near earth asteroids have near circular orbits of less than 365 days. Neil
I would like to see us land on the asteroid that is passing very close to earth in 2028 and then with a VERY slight chance of hitting earth in 2036 for two reasons. 1) it should be a very cheap mission, rendevous with it a few lunar distances from earth and then leave it as it gets close to earth for a short ride home. 2) Since it could hit earth at some point, it is certainly an asteroid that we need to know a LOT about. BTW, one downside is that we would need to ensure that our landing on the asteroid does not change its orbit, such that it becomes MORE likely to hit earth.
Mithradates- I agree. It's also astonishing how people can say, "We've been to the Moon. We've explored it. Been there, done that." Amazing! We've hardly explored the Moon.
Even Buzz Aldrin said as much. He said, "We've already been to the Moon. We should go to Mars."
No Buzz!!! You and 11 other guys have been to the Moon. The rest of us watched it on TV! :x
Even Buzz Aldrin said as much. He said, "We've already been to the Moon. We should go to Mars."
No Buzz!!! You and 11 other guys have been to the Moon. The rest of us watched it on TV! :x
I was hoping one of the resident propulsion experts would chime in but I guess they are not interested. So far we have not been able to build a space vehicle of any size that could do anything more than make minor course corrections. So far we have had to use the gravity wells of planets to make big course changes. I don't have the expertise to prove that a return from an asteroid can or cannot be executed with a space vehicle that we could currently build. We have already proved that a moon lander can be built and there is sufficient data to build a larger one. If we can't land on the moon how the heck do you think we could ever land on Mars? Furthermore a landing on an asteroid would have to deal with it's gravity which depending on how irregular it is could vary wildly on approach. The President may have sold some oj us on his wild ass scheme but not me.orionrider":d8i72jgb said:The Moon has gravity, which means you need to design and test a new lander with braking rockets, legs, high structural integrity and all that, plus an ascent stage. It would take many years and lots of €$.
Landing and taking off from a passing asteroid costs nothing more than reversing course in deep space. You can do it in the near future using an existing spacecraft and regular EVA suits. All you need is more propellant. In fact the mission would be very similar to servicing a satellite, but then not in Earth orbit. I'm sure there are enough Near Earth Asteroids to choose one that has a limited delta-v, so it doesn't cost too much.
It would be a useful test of hardware, navigation, deep space communications, EVA procedures, life support, etc.
The first time people leave Earth orbit. International mission, very symbolic, historical day, live on CNN, etc. :mrgreen:
And as 'a_lost_packet' said, it could even be useful...
Actually you bring up a good point. 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.
There's an article in Science News that mentions candidates; I'll list them and look up the stats later.
MW
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.
There's an article in Science News that mentions candidates; I'll list them and look up the stats later.
MW
MW, that is precisely the point I was trying to make. We just don't have the capability to manuver in space like they do in Star Trek, which I'm beginning to think most of the younger generation assumes we have mastered. Heck we still have trouble docking in earth orbit. The little probes that have successfully landed on asteroids only weigh a few kilograms. I'd bet that we are several decades from having engines that are capable of such a feat with a vehicle big enough for a manned crew. I think Obama has flim flammed the whole nation on this one and if we continue to let him push NASA in this direction we will be out of manned space flight fo many years to come.
I think distance is not that much of a problem, but acceleration is. A ticket to bring a 30 ton vehicle (like Apollo CM + SM) to a delta-v of 2 x 7.4 km/sec is prohibitively expensive by today's standards.
However, until 2029 (for Apophis) the electrical (VASIMR) propulsion has just enough time to mature. The mission could even be much cheaper if there were some usable reaction mass (water ice) on the asteroid for the return ticket. But you can't really count on it :?
However, until 2029 (for Apophis) the electrical (VASIMR) propulsion has just enough time to mature. The mission could even be much cheaper if there were some usable reaction mass (water ice) on the asteroid for the return ticket. But you can't really count on it :?
bdewoody":3lv91rif said:
I was just providing support for your point. Stuff moves fast out there, and matching speeds to land and getting rid of the speed to get back is the key issue.
One minor correction, the NEAR spacecraft that landed on Eros had a mass of more than 487 kg at landing...that's the mass with no propellant, and it did have some left. Now certainly a manned vehicle would weigh a heck of a lot more.
I'm currently looking at asteroids of Apophis size (250m) and larger that come within 10x lunar distance before 2200. I'll weed down the list as I process the data. I figure anything smaller isn't worth visiting, and would have so little gravity that staying there would be extremely difficult.
MW
orionrider":2qyi0055 said:
The problem is that with VASIMR's low ISP, a mission for 2 weeks on the surface might take 3 years in transit there and back. That creates huge logistical problems.
I'm really beginning to think a lot of today's youth have a distorted understanding of what it takes to manuver in space. Once you start in a particular direction it takes a lot of energy to say make a 90 degree turn and even more to make a 180. It isn't like flying in air at all. And it's surely not like space flight is depicted in arcade games. Most of our manuvering in space uses gravity assists to make course changes and to speed up or slow down.
MW, I read VASIMR could one day (?) make the trip to Mars possible in 39 days :?
http://www.space.com/businesstechnology ... 807-1.html
http://news.discovery.com/space/mars-ro ... -nasa.html
http://www.newscientist.com/article/dn1 ... -mars.html
It seems the technology holds its promises, at least until now: viewtopic.php?f=15&t=24548
Of course it is still a very long way from the required megawatts to make it practical. What do you think :?:
http://www.space.com/businesstechnology ... 807-1.html
http://news.discovery.com/space/mars-ro ... -nasa.html
http://www.newscientist.com/article/dn1 ... -mars.html
It seems the technology holds its promises, at least until now: viewtopic.php?f=15&t=24548
Of course it is still a very long way from the required megawatts to make it practical. What do you think :?:
I don't really see hte point either, except to prove that we can do it. If we had one with a 'safe' orbit between here and Mars, we might want to check it out and see what kinds of resources are there...but we could use robots or other means. The main concern I have is that, before, we've had gravity or all kinds of fancy tethers. On a sizable asteroid, you won't so much. Will we get an astronaut flying off to his doom?
I honestly doubt that anyone will have a plasma engine ready for a manned mission to an asteroid within 20 years. So far they are only capable of powering a small robotic craft weighing a few kilograms. I think it is way too risky to attemp at this date.
I would like to see a paper written by a bonafide aerospace engineer certifying that it would take less energy to go to one of the moons of Mars than to go to our moon. On the surface that seems absurd since the volume of supplies needed to go for a year is vastly greater than what is needed to go to the moon. I would think 5 or 6 moon missions could be flown using less fuel and supplies than a single mission to Phobos or an asteroid out near Mars.
And now I'm reading that there is most likely a great deal more water on the moon than was thought just a few months ago. So I think our President should rethink the goals he is setting for our future and put the moon back on the top of the list.
I would like to see a paper written by a bonafide aerospace engineer certifying that it would take less energy to go to one of the moons of Mars than to go to our moon. On the surface that seems absurd since the volume of supplies needed to go for a year is vastly greater than what is needed to go to the moon. I would think 5 or 6 moon missions could be flown using less fuel and supplies than a single mission to Phobos or an asteroid out near Mars.
And now I'm reading that there is most likely a great deal more water on the moon than was thought just a few months ago. So I think our President should rethink the goals he is setting for our future and put the moon back on the top of the list.
Didn't they say that asteroids contain metals/minerals and stuff? Who knows where asteroids come from or what they contain? The moon has stayed in the "same" place ever since. Asteroids travel and such, I think that makes them good objects to land on and study cause they've been "around"?
It took the USA $170,000,000,000 (2005 valuta) to bring back 382kg of Moon rocks.
A trip to an asteroid would be more expensive, but it gives you an idea of what it really costs
Even if they found pure platinum
on an asteroid, it would take 3,400,000 kg of the stuff to pay for a similar budget.You have to find about 113 tons of (bottled, ready-to-use) Helium3 to make such a trip worthwhile. :shock:
Jewelry-quality uncut diamond would be about 70,000 kg...
Asteroid or Moon mining is not going to happen anytime soon
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