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#40 by Robotbeat on 25 Mar, 2012 21:44
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A SEP stack capable of pushing the exploration gateway to a Phobos/Deimos mission is capable of several NEA targets. And if you can go to Phobos/Deimos, you can go to the surface of Mars just by adding a lander. Thus a NEA mission is a great way to get additional use out of the beginnings of a Mars architecture. Like an actually productive version of Apollo 8.
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#41 by Chris Bergin on 25 Mar, 2012 23:35
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I doubt the Launch Pad is the restricting factor on the 121 day turnaround, so a Pad C wouldn't aid things....if that's what the recent posts are about.
I quite agree.QuoteAlso, I'm thinking of setting up a poll as I've seen a few people fail to be excited about NEA mission - say in comparision to the Moon.
Is that a fair comparison? Should be lunar sortie missions, because if you compare a NEA mission to a lunar base (which is what I think several people would be excited about), you're comparing something with very different levels of funding.
Yeah, that poll question and options will require some thought for that very reason. I'll sleep on it!
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#42 by TomH on 26 Mar, 2012 02:58
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....if you can go to Phobos/Deimos, you can go to the surface of Mars just by adding a lander.
It sounds like you are suggesting high V transport, short stay sortie, no radiation shielding for the surface, no transportation vehicles? Basically Apollo 11: land, get out, put up a flag, take a walk, set up some experiments, get in, take a nap, leave. Otherwise, there's a whole lot more to it than just adding a lander. You'd be talking several extremely large landers all having to land in the same place. Landing on Mars is not like landing on Luna. I'm just hoping Curiosity makes it down at this point. We should learn a lot from that descent.Thus a NEA mission is a great way to get additional use out of the beginnings of a Mars architecture. Like an actually productive version of Apollo 8.
A survey of Phobos with sample returns would be a huge boon to the study of Mars geology. You'd learn things about early Mars that you couldn't from Mars sample returns.
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#43 by Robotbeat on 26 Mar, 2012 03:10
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Quite right, but it may be wise for the first mission to be a short-stay (though I usually argue for long-stay). The next could be long-stay, but all the surface components beyond the basic lander would be pre-placed and pre-deployed.....if you can go to Phobos/Deimos, you can go to the surface of Mars just by adding a lander.
It sounds like you are suggesting high V transport, short stay sortie, no radiation shielding for the surface, no transportation vehicles? Basically Apollo 11: land, get out, put up a flag, take a walk, set up some experiments, get in, take a nap, leave. Otherwise, there's a whole lot more to it than just adding a lander....
There's some wisdom in having a gradual envelope expansion of human habitation in space. If long-stay weren't so much more advantageous from a delta-v standpoint, it'd be pretty obvious that the first one should be a 30-day stay, not a ~year stay.
We had an Apollo 11 which stayed a very short time before leaving, later we had the "J-missions" starting with Apollo 15 which had significantly longer stays, a lunar rover, etc. Gradual envelope expansion makes sense, usually.
Because of the delta-v difference, it's a really tough call. -
#44 by RocketmanUS on 26 Mar, 2012 04:12
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There is a good reason to have a long stay on the moon first. To see if we can. If we can stay for a long time ( 3 years ) then we would have a good bet that we could stay on Mars for the time until the return window opened up for that mission.
Quite right, but it may be wise for the first mission to be a short-stay (though I usually argue for long-stay). The next could be long-stay, but all the surface components beyond the basic lander would be pre-placed and pre-deployed.....if you can go to Phobos/Deimos, you can go to the surface of Mars just by adding a lander.
It sounds like you are suggesting high V transport, short stay sortie, no radiation shielding for the surface, no transportation vehicles? Basically Apollo 11: land, get out, put up a flag, take a walk, set up some experiments, get in, take a nap, leave. Otherwise, there's a whole lot more to it than just adding a lander....
There's some wisdom in having a gradual envelope expansion of human habitation in space. If long-stay weren't so much more advantageous from a delta-v standpoint, it'd be pretty obvious that the first one should be a 30-day stay, not a ~year stay.
We had an Apollo 11 which stayed a very short time before leaving, later we had the "J-missions" starting with Apollo 15 which had significantly longer stays, a lunar rover, etc. Gradual envelope expansion makes sense, usually.
Because of the delta-v difference, it's a really tough call.
We would need to send at least enough equipment for two outposts ( small base, 3 pieces ) stocked with supplies and three SEV's per outpost for crew safety and mission success.
The possible NEA mission(s) with the lunar missions should give us all the training we need for Mars.
With the right planning the flight rates can be there for SLS and the support launchers ( U.S. and others ) to support these missions. Then we can have Mars mission(s) once we have gathered enough training and info from the other two and still have crew on the moon. -
#45 by Cherokee43v6 on 26 Mar, 2012 17:46
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Hmmm... reading this article sparked a thought, perhaps something that would warrant its own conversation, perhaps not.
One of the books in my personal library is John S. Lewis' 'Mining the Sky'. In it, he devotes a chapter to the concept of a 'Cycler' asteroid/ship that moves between Earth and Mars orbit carrying colonists.
The thought that popped into my mind was a hybrid concept, namely identifying NEA's that are already on such trajectories and then having the Mars exploration ships shadow them on the trips out and back from Mars.
Why? I can think of two solid reasons.
1) Radiation shielding. In the event of a solar flare, the ship could move into the shadow of the asteroid and use its mass to block the worst radiation effects.
2) Something to do while in transit. The crew would have the ability to explore and fully catalog the asteroid while in transit.
Complications?
1) Complexity of mission design requiring rendezvous with two different asteroids (one going, one coming).
2) Extra resources required for a potentially longer transit and wait for return ride.
Thoughts? -
#46 by Robotbeat on 26 Mar, 2012 17:55
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The biggest issue with cyclers is the need for much greater delta-v to get to and from them.
Radiation from solar flares is actually reasonably easy to engineer away. A few inches of water can eliminate the vast majority of the acute risk. GCRs are another story, though they do not have an acute risk associated with them. -
#47 by Lobo on 26 Mar, 2012 18:59
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The 'Pad 39C' concept wouldn't have to look exactly like the previous at all - other than being big. Slide-on, slide-off adaptors, platforms and other equipment could be made to make 2 or 3 different launchers use the facility.
The Pad 39C concept exists in a world very different from the one we inhabit. Biggest difference is a very large increase in NASA's budget (which I'd support, of course).
I mean, yeah, with enough money we could do all these crazy things. But we are budget-constrained.
It's questionable that NASA will even use the two pads they already have at this point. So I woudln't worry about 39C for awhile (ever). -
#48 by Lobo on 26 Mar, 2012 19:31
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I doubt the Launch Pad is the restricting factor on the 121 day turnaround, so a Pad C wouldn't aid things....if that's what the recent posts are about.
Also, I'm thinking of setting up a poll as I've seen a few people fail to be excited about NEA mission - say in comparision to the Moon.
*snip*
And as for the 'Moon vs NEA' excitement level: Man on the Moon has almost mythic status, whereas visiting one NEA, then another is going to cause more than one smart-alec to say; "Hey; didn't Bruce Willis do that in some old movie?"
The Moon is a world, a very small asteroid is not. But it would be interesting. Also, developing even a simple 2-man lunar Lander is going to be - at least - a $10 Billion dollar project. Far less than that could be done developing the MPLM-based Hab, an airlock module and a SEV-based 'asteroid lander'.
X2!
I whole heartedly agree.
I do see the scientific merits of a NEO. But I don’t see much in the way of public interest for a flagship class NASA HSF mission, considering the costs and technical challenges of such a mission. I’d like to see NASA do one some time, but I think a Moon landing, along with some extended duration missions/outpost, etc there would be many times more interesting to the public than a NEO. The Moon is the largest and most obvious “NEO” there is, and we barely scratched the surface. As much as I love Buzz Aldrin, I couldn’t disagree with him more when he endorsed the Flexible Path saying, “We’ve already been to the Moon. Been there done that” (paraphrasing). Other Apollo astronauts have a drastically different view about returning to the moon. It –almost- seems like Buzz doesn’t want his almost mythic status as the 2nd man to walk on the moon, and one of only 12 to every do so, to be marginalized by a whole bunch of new astronauts doing it. I am probably misreading that about him, but I can’t see why he’d be so dismissive about returning to the moon after we’d done so little there, so long ago. Fellow Moon walkers Armstrong, Young and Cernan have strongly endorsed going back first.
I think there’s much more to be learned about going to Mars by going to the Moon first, than there is about going to a NEO first, IMO.
Once we’ve gotten back on the Moon, and are habitating there, and are developing technologies to that effect, then we could design a space hab, based on whatever hab tech we’d developed for the moon. Then we can wait for a really choice NEO that’s interesting, hopefully large, and in an orbit that doesn’t take extraordinarily long to get to and back from.
I don’t know, just seems like we are mission the 800 lb gorilla in the room by talking about a NEO as the initial focus, rather than the Moon. And the Moon seems like it would be far more interesting to explore than a NEO. At least at first.
What I think might be interesting for a lunar program, is an SEV derived crew lander. That could either be a smaller vertical lander with an SEV based Ascent Module if two stage, or SEV based crew cabin if single stage. If the lander is something like an ACES horizontal lander, it could have and SEV based reusable AM or cockpit. So even the SEV concept could be refined and then some version of the SEV AM could be the NEO explorer vehicle.
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#49 by Lobo on 26 Mar, 2012 19:48
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There's no such thing as extreme low gravity. It's either low or it's not.
As far as long term goes, Russian cosmonauts have been in zero-g for more than a year at a time. They were weak when they returned to earth but otherwise healthy. They recovered their strength as they re-acclimated to full-g.
WEll, we can easily test prolong exposure to zero-g on the ISS. We can put a guy up there for ever a year if we want. and remove him if there's any health problems while he's there. Easy enough.
What we can't test out is prolonged exposure to "low" gravity, such as the Moon's, Mars, or some sort of artificial gravity during a long term mission. We don't know if the body's reaction to gravities bewteen zero and 1g is linear, or something else. It could be that exposure to 1/6 gravity woudl allow a person to greatly reduce their muscle and bone loss, especially if they where body weights to make themselvses heavier. (something that can't be done is zero-g, no matter your mass, if there's no graivty, there is no resistance on the body). Or 1/6 gravity might simply be a little less bone and muscle loss than zero-g. 1/2 gravity being 1/2 muscle and bone loss, etc.
WE don't know, but an outpost of some kind on the Moon where we could put astronauts for 6 months or more at a time, could tell us some of that. A VERY useful bit of info for Mars missions, or other long duration mission if there's any potential for considering generating artificial gravity. -
#50 by Robotbeat on 26 Mar, 2012 20:07
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And such a Moon base operated for ten years may very well cost the same as the first Mars mission.There's no such thing as extreme low gravity. It's either low or it's not.
As far as long term goes, Russian cosmonauts have been in zero-g for more than a year at a time. They were weak when they returned to earth but otherwise healthy. They recovered their strength as they re-acclimated to full-g.
WEll, we can easily test prolong exposure to zero-g on the ISS. We can put a guy up there for ever a year if we want. and remove him if there's any health problems while he's there. Easy enough.
What we can't test out is prolonged exposure to "low" gravity, such as the Moon's, Mars, or some sort of artificial gravity during a long term mission. We don't know if the body's reaction to gravities bewteen zero and 1g is linear, or something else. It could be that exposure to 1/6 gravity woudl allow a person to greatly reduce their muscle and bone loss, especially if they where body weights to make themselvses heavier. (something that can't be done is zero-g, no matter your mass, if there's no graivty, there is no resistance on the body). Or 1/6 gravity might simply be a little less bone and muscle loss than zero-g. 1/2 gravity being 1/2 muscle and bone loss, etc.
WE don't know, but an outpost of some kind on the Moon where we could put astronauts for 6 months or more at a time, could tell us some of that. A VERY useful bit of info for Mars missions, or other long duration mission if there's any potential for considering generating artificial gravity. -
#51 by Rocket Science on 26 Mar, 2012 20:31
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Mars is a world, the Moon is a world, NEA's are just a "rock in space". Sorry, it just does not rate like a Flagship mission as a destination... Further, to add that we "explored" the Moon already, sorry again, we just "visited" and that was over 40 years ago...
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#52 by Robotbeat on 26 Mar, 2012 20:57
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Mars is a world, the Moon is a world, NEA's are just a "rock in space". Sorry, it just does not rate like a Flagship mission as a destination... Further, to add that we "explored" the Moon already, sorry again, we just "visited" and that was over 40 years ago...
The Moon is kind of just a rock in space, too. No atmosphere to speak of, about as unlikely as the asteroids to be a home to a self-sufficient colony.
And what the heck are you apologizing in a condescending way for?
The road to developing an architecture capable of a manned mission to Mars goes past the NEAs. They are so shallow of gravity wells that you could just do an EVA to their surface (with the MTV station-keeping nearby), without having to build a lander or otherwise modify your Mars Transfer Vehicle. They present an existential threat to humanity, thus studying them is quite valuable, as is developing the infrastructure and experience to put a very large payload in their vicinity (i.e. the solar-electric propulsion unit, which is just as useful for a Mars mission).
Don't get me wrong, Moon missions would also be cool, but don't dismiss a valuable and unique mission just because you like the Moon so much. -
#53 by Rocket Science on 26 Mar, 2012 21:15
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Hey Robot,Mars is a world, the Moon is a world, NEA's are just a "rock in space". Sorry, it just does not rate like a Flagship mission as a destination... Further, to add that we "explored" the Moon already, sorry again, we just "visited" and that was over 40 years ago...
The Moon is kind of just a rock in space, too. No atmosphere to speak of, about as unlikely as the asteroids to be a home to a self-sufficient colony.
And what the heck are you apologizing in a condescending way for?
The road to developing an architecture capable of a manned mission to Mars goes past the NEAs. They are so shallow of gravity wells that you could just do an EVA to their surface (with the MTV station-keeping nearby), without having to build a lander or otherwise modify your Mars Transfer Vehicle. They present an existential threat to humanity, thus studying them is quite valuable, as is developing the infrastructure and experience to put a very large payload in their vicinity (i.e. the solar-electric propulsion unit, which is just as useful for a Mars mission).
Don't get me wrong, Moon missions would also be cool, but don't dismiss a valuable and unique mission just because you like the Moon so much.
No condescension meant to anyone in particular here on this forum. If any disdain on my behalf is directed to the authors of the so-called roadmap and trying to sell it to the populace and congress.
What came to mind is this…
~“we choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard”
John F. Kennedy
~“Mars is hard…”
Charlie Bolden
I really don’t get this malaise and fear of doing things that are hard
anymore…
Regards
Robert
P.S. I’ll let Warren lecture you again on the Moon thing…
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#54 by Robotbeat on 26 Mar, 2012 21:18
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Mars is hard, which is why we're doing it! That's the whole reason to do these NEA missions, because they provide a useful mission to do that uses the hardware for a Mars mission to do an intermediate goal while we develop and shake-down the rest of the architecture. It's like Gemini or the early Apollo missions (before Apollo 11), except with better scientific return.
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#55 by Rocket Science on 26 Mar, 2012 21:31
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Mars is hard, which is why we're doing it! That's the whole reason to do these NEA missions, because they provide a useful mission to do that uses the hardware for a Mars mission to do an intermediate goal while we develop and shake-down the rest of the architecture. It's like Gemini or the early Apollo missions (before Apollo 11), except with better scientific return.
Yes, I get that. But with Gemini we had a hard target… the Moon. The way they have been selling this that we are going to an asteroid and yes some day after that we’ll go to Mars… someday…
If we go to Phobos, for example, the public is going to ask why we didn’t land on Mars instead. We can’t use “Mars is hard” and expect them to understand and buy it. They would see it as going on a road trip across country to see the Empire State Building in NYC and not going up to the top when you got there.
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#56 by MP99 on 26 Mar, 2012 21:43
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WE don't know, but an outpost of some kind on the Moon where we could put astronauts for 6 months or more at a time, could tell us some of that. A VERY useful bit of info for Mars missions, or other long duration mission if there's any potential for considering generating artificial gravity.
And such a Moon base operated for ten years may very well cost the same as the first Mars mission.
After such an expensive, but sustained campaign on the Moon, surely this would provide experience to reduce the costof the subsequent Mars mission?
cheers, Martin -
#57 by Robotbeat on 26 Mar, 2012 21:45
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What? With these NEA missions, we have a target, too: Mars. When Obama announced the change of direction, he set the mission end-point and primary focus on Mars. The NEAs are interesting science mission targets in their own right (a significant improvement from Gemini), but it's critical we get deep space operating experience before going to Mars for hundreds and hundreds of days. How would the public respond if we just did a mission to an empty point in space instead?Mars is hard, which is why we're doing it! That's the whole reason to do these NEA missions, because they provide a useful mission to do that uses the hardware for a Mars mission to do an intermediate goal while we develop and shake-down the rest of the architecture. It's like Gemini or the early Apollo missions (before Apollo 11), except with better scientific return.
Yes, I get that. But with Gemini we had a hard target… the Moon. The way they have been selling this that we are going to an asteroid and yes some day after that we’ll go to Mars… someday…
If we go to Phobos, for example, the public is going to ask why we didn’t land on Mars instead. We can’t use “Mars is hard” and expect them to understand and buy it. They would see it as going on a road trip across country to see the Empire State Building in NYC and not going up to the top when you got there.
And if we had enough funding to also have a reusable lunar lander, the same platform would work very good for supporting a extensive lunar campaign as well. The high-power SEP tug would be quite efficient at moving a lot of cargo from a lower Earth orbit to the vicinity of the Moon and back, with the rest of the exploration stack working as a gateway to dock the reusable lunar lander and support its refurbishment and checkout between missions along with supporting low-latency lunar telepresence. -
#58 by A_M_Swallow on 26 Mar, 2012 21:56
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If we go to Phobos, for example, the public is going to ask why we didn’t land on Mars instead. We can’t use “Mars is hard” and expect them to understand and buy it. They would see it as going on a road trip across country to see the Empire State Building in NYC and not going up to the top when you got there.
The answer is that NASA is building the spacestation on Phobos. There are plenty of towns where the railway stops outside the town and you get a taxi to your hotel. The large inter-planetary spacecraft are not designed to operate in an atmosphere and it would be too expensive to make them. -
#59 by Rocket Science on 26 Mar, 2012 22:04
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Perhaps it is a nuance thing. We watched Charlie in testimony evolve his explanation of the proposal over the last couple of years to include Mars. If it is a Mars program, call it that and all other missions are less the focus. They way NASA has shown it is the other way around. He speaks more about capabilities than the target Mars. It is how I have perceived it and congress seems a little “fuzzy” on it too.
What? With these NEA missions, we have a target, too: Mars. When Obama announced the change of direction, he set the mission end-point and primary focus on Mars. The NEAs are interesting science mission targets in their own right (a significant improvement from Gemini), but it's critical we get deep space operating experience before going to Mars for hundreds and hundreds of days. How would the public respond if we just did a mission to an empty point in space instead?Mars is hard, which is why we're doing it! That's the whole reason to do these NEA missions, because they provide a useful mission to do that uses the hardware for a Mars mission to do an intermediate goal while we develop and shake-down the rest of the architecture. It's like Gemini or the early Apollo missions (before Apollo 11), except with better scientific return.
Yes, I get that. But with Gemini we had a hard target… the Moon. The way they have been selling this that we are going to an asteroid and yes some day after that we’ll go to Mars… someday…
If we go to Phobos, for example, the public is going to ask why we didn’t land on Mars instead. We can’t use “Mars is hard” and expect them to understand and buy it. They would see it as going on a road trip across country to see the Empire State Building in NYC and not going up to the top when you got there.
And if we had enough funding to also have a reusable lunar lander, the same platform would work very good for supporting a extensive lunar campaign as well. The high-power SEP tug would be quite efficient at moving a lot of cargo from a lower Earth orbit to the vicinity of the Moon and back, with the rest of the exploration stack working as a gateway to dock the reusable lunar lander and support its refurbishment and checkout between missions along with supporting low-latency lunar telepresence.
