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NASA builds asteroid capture mission definitions
by
Chris Bergin
on 31 Mar, 2014 20:14
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#1
by
Rocket Science
on 31 Mar, 2014 20:25
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Congratulations on a great article Mike!
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#2
by
clongton
on 31 Mar, 2014 20:28
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Interesting article Mike, thanks.
It's good to see the consideration of other launch vehicles than the SLS. Provides more options.
I'd be interested in this "bag" capture and de-spin component. Any information available for that?
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#3
by
butters
on 31 Mar, 2014 21:44
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Have they considered a direct mechanical coupling, perhaps like Altius' "Sticky Boom" and/or a drill-like component to grasp onto the object and secure it to the spacecraft? This seems more feasible to scale up for a future planetary defense asteroid deflection system. The bag approach seems like a dead end in terms of scale.
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#4
by
Coastal Ron
on 31 Mar, 2014 21:49
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Agreed, good article. Interesting to see how the asteroid capture aspect has been evolving over time.
It was also interesting to see that apparently NASA has officially determined that using the EM-2 mission as part of the ARRM was not feasible, so I guess that means EM-2 can now be less complicated and focus on just the basics.
If part of the reason for the ARM/ARRM mission was to provide an initial mission for the SLS and Orion/MPCV (which some believe), then now that the SLS/MPCV are no longer the driving force for this mission the justification for the ARRM needs to be very clear - how does it fit within NASA's long-term plans? What purpose does creating an ability to retrieve part of all of an asteroid serve? Is it more of a science expedition like what we're doing with Curiosity on Mars, or is it supposed to be connected to our HSF plans?
Other than being a destination for a future HSF mission, I'm not sure what value it holds for HSF in general. All things considered I'd rather use the money to fund in-space tests of fuel depots, SEP or radiation mitigation technologies. And if it's science that is driving this, then it needs to compete with all the other robotic missions that are being proposed, including the Europa one.
Also, since there are now funded private companies that are interested in mining asteroids, I think it would be worth partnering with the private sector to see how NASA can stretch it's budget AND help promote the U.S. space industry at the same time. Making this a government-only proposition when private entities are already spending money in this space would be a waste of taxpayer money.
Of course there is a lack of political consensus for this proposed mission (to say the least). But I think the study portion is worthwhile pursuing since NEO's are kind of "low hanging fruit" by being so close. But I'm just not sure this effort should be the highest priority right now.
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#5
by
Khadgars
on 31 Mar, 2014 22:09
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Other than being a destination for a future HSF mission, I'm not sure what value it holds for HSF in general. All things considered I'd rather use the money to fund in-space tests of fuel depots, SEP or radiation mitigation technologies. And if it's science that is driving this, then it needs to compete with all the other robotic missions that are being proposed, including the Europa one.
One of the main driving factors for this mission is the utilization of SEP. You are getting SEP demonstration along with BLEO HSF experience in one early mission. As the article states, the spacecraft is also being designed with future use in mind
The spacecraft is also to be designed with possible future use in mind, so that the basic vehicle can be used as the basis for cargo delivery to support a future notional Phobos mission.
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#6
by
A_M_Swallow
on 31 Mar, 2014 22:37
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One of the main driving factors for this mission is the utilization of SEP. You are getting SEP demonstration along with BLEO HSF experience in one early mission. As the article states, the spacecraft is also being designed with future use in mind
The spacecraft is also to be designed with possible future use in mind, so that the basic vehicle can be used as the basis for cargo delivery to support a future notional Phobos mission.
High level design decision. Will the SEP be man rated or cargo only?
This mission is cargo only but Mars missions could use a SEP for return transport.
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#7
by
A_M_Swallow
on 31 Mar, 2014 22:42
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Have they considered a direct mechanical coupling, perhaps like Altius' "Sticky Boom" and/or a drill-like component to grasp onto the object and secure it to the spacecraft? This seems more feasible to scale up for a future planetary defense asteroid deflection system. The bag approach seems like a dead end in terms of scale.
It has been considered. A 'Sticky Boom' or drill will work when the asteroid is a solid object but not when the asteroid is a rouble cloud. The boom will grab a few stones but the rest will continue on their dangerous path.
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#8
by
arachnitect
on 31 Mar, 2014 22:50
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Nice write up.
I think it would be a fascinating mission. I remember there being a lot of skepticism when this was first proposed, so I'm glad to see it surviving further study.
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#9
by
Coastal Ron
on 31 Mar, 2014 23:34
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One of the main driving factors for this mission is the utilization of SEP. You are getting SEP demonstration along with BLEO HSF experience in one early mission. As the article states, the spacecraft is also being designed with future use in mind
The spacecraft is also to be designed with possible future use in mind, so that the basic vehicle can be used as the basis for cargo delivery to support a future notional Phobos mission.
Yes I saw that, but a HSF Mars mission is decades off at the very least, so anticipating what kind of cargo vehicles we'll need is very premature. Not only that we already have two companies that operate LEO cargo vehicles, so autonomous cargo delivery is not something that NASA needs to worry about right now - the private sector can do that.
The SEP part is good, since it could be matured for use in many future spacecraft. But that's about all I can see that would be used for HSF. As to BLEO HSF, delivering a science payload to a point in space that is reachable by the MPCV is not really an enabling technology for HSF per se, just providing more potential destinations.
Which is why I asked if the ARRM is supposed to be funded out of the HSF part of NASA (i.e. Exploration) or the robotic exploration (i.e. Science) part? Or maybe both. Regardless it needs to be competed against other uses for the same funds, AND the payoff needs to be clear enough to get the so-far reticent politicians to back it. Even the space community isn't enthusiastic about the ARRM, so it's no surprise that it's having trouble gaining support in Congress. A clearer value proposition would help.
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#10
by
muomega0
on 01 Apr, 2014 00:33
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One of the main driving factors for this mission is the utilization of SEP. You are getting SEP demonstration along with BLEO HSF experience in one early mission. As the article states, the spacecraft is also being designed with future use in mind
The spacecraft is also to be designed with possible future use in mind, so that the basic vehicle can be used as the basis for cargo delivery to support a future notional Phobos mission.
Yes I saw that, but a HSF Mars mission is decades off at the very least, so anticipating what kind of cargo vehicles we'll need is very premature. Not only that we already have two companies that operate LEO cargo vehicles, so autonomous cargo delivery is not something that NASA needs to worry about right now - the private sector can do that.
The SEP part is good, since it could be matured for use in many future spacecraft. But that's about all I can see that would be used for HSF. As to BLEO HSF, delivering a science payload to a point in space that is reachable by the MPCV is not really an enabling technology for HSF per se, just providing more potential destinations.
Which is why I asked if the ARRM is supposed to be funded out of the HSF part of NASA (i.e. Exploration) or the robotic exploration (i.e. Science) part? Or maybe both. Regardless it needs to be competed against other uses for the same funds, AND the payoff needs to be clear enough to get the so-far reticent politicians to back it. Even the space community isn't enthusiastic about the ARRM, so it's no surprise that it's having trouble gaining support in Congress. A clearer value proposition would help.
If one of the mission goals was to extend the duration of the Mars transport vehicle, then ARRM would indeed be relevant to HSF. Unfortunately, some folks were mislead that Orion was supposed to head to Mars (per Mars DRM 5). It is surprising that HSF does not abandon Orion for a DSH. It points out the deficiencies of a "capability driven approach"....if the capability dne in an political environment that does not want to develop technology....there is not much left to do. Same can be said for a LV that has no payload...but perhaps that's the goal...a long term contract with no deliverable.
If the return mass from Mars was pre-positioned, then the HSF trip time can be reduced substantially. That was the initial goal of ZBO LH2 depots--to reduce trip times for long duration travel, since the real mass to sustain crew is substantial without R&D. IOW: staging combined with a re-usable high ISP tug to reduce IMLEO. No worries...100s of mT of mass should give the commercial LV a stable source of income until it can get its legs...
Of course, at a 1.2B price tag, and with SLS in the 500-700M range, there is not a lot left over for the rest of the mission. Hopefully, it will not get the 'Albatross' label.....perhaps this is the goal?
One way the SEP stage could be designed is to provide the capability to add power and additional thrust at a later date, similar to the ISS buildup. The SEP stage could be returned to L2 and incrementally increased in capacity through either robotic and/or HSF assembly and servicing. It would make little sense to design the SEP to be expendable given that most of the components should have years or even decades of lifetime.
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#11
by
A_M_Swallow
on 01 Apr, 2014 02:07
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{snip}
The SEP part is good, since it could be matured for use in many future spacecraft. But that's about all I can see that would be used for HSF. As to BLEO HSF, delivering a science payload to a point in space that is reachable by the MPCV is not really an enabling technology for HSF per se, just providing more potential destinations.
{snip}
Human Space Flight (HSF) will also received the first manned docking outside of LEO since Apollo.
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#12
by
Coastal Ron
on 01 Apr, 2014 02:28
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One way the SEP stage could be designed is to provide the capability to add power and additional thrust at a later date, similar to the ISS buildup. The SEP stage could be returned to L2 and incrementally increased in capacity through either robotic and/or HSF assembly and servicing.
I know I certainly prefer not to throw away assets we've spent so much money to launch to space in the first place, so building an upgradeable SEP "bus" would be a good idea.
It would make little sense to design the SEP to be expendable given that most of the components should have years or even decades of lifetime.
Agreed. And for that reason it makes even more sense for the SEP vehicle to be privately built and run, since companies can do a better job of finding uses for that type of capability over a long period of time. Otherwise NASA would be saddled with yet something else that it has to maintain every year, regardless if it uses it or not.
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#13
by
muomega0
on 01 Apr, 2014 11:07
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One way the SEP stage could be designed is to provide the capability to add power and additional thrust at a later date, similar to the ISS buildup. The SEP stage could be returned to L2 and incrementally increased in capacity through either robotic and/or HSF assembly and servicing.
I know I certainly prefer not to throw away assets we've spent so much money to launch to space in the first place, so building an upgradeable SEP "bus" would be a good idea.
It would make little sense to design the SEP to be expendable given that most of the components should have years or even decades of lifetime.
Agreed. And for that reason it makes even more sense for the SEP vehicle to be privately built and run, since companies can do a better job of finding uses for that type of capability over a long period of time. Otherwise NASA would be saddled with yet something else that it has to maintain every year, regardless if it uses it or not.
If a company did not make SEP in a modular fashion, NASA would have to pay for yet another development for the Mars class EP, all at the taxpayer expense. If a company built a methane depot...? If a company reverted back to lead batteries to cheapen their up front costs but maximize launch costs to the government...? If the company decides to leave the business?
By privately built and run, do you mean private funding? The current model is that the government pays companies to launch, fly, and operate satellites and stations, and these same companies build satellites for the communications companies, having once also launched them too (leaves the business since they are no longer profitable). What is different from this approach? Is this government or privately developed?
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#14
by
darkbluenine
on 01 Apr, 2014 14:48
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A good update, but the article overstates a couple things:
One, the article's conclusion is overstated:
... NASA is aggressively pursuing to ARRM concept and has demonstrated that there are no technological roadblocks to implementation.
The key technologies necessary to implement this mission -- high-power SEP, the deep space rendezvous system, the capture mechanism, and the despin procedure -- have yet to be demonstrated at any level. High-level, generic analyses don't count as demonstrations. It's impossible to state at this time that there are "no technological roadblocks". Until we get further into actual development -- and possibly not until the mission is over -- will we know whether there are "no technological roadblocks" to ARM.
Two, the claims about planetary defense demonstrations in the article are also overstated:
Significantly, a planetary defense demo has been proposed for each of the mission concepts to prove out gravity tractor and/or ion beam deflection (IBD) concepts. For an object similar to 2009 BD (<500 tonne), a Δv of ~ 1mm/sec could be imparted in roughly 1 hr using IBD and about 30 hrs using gravity tractor.
These may be proofs-of-concept, but they are not "planetary defense demos". Too little energy is being imparted to too small a target with too much warning time. We could not take this system and divert an actual, dangerous NEO.
Again, a good update, but we should be careful when making absolute statements or making claims about supposed planetary defense capabilities.
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#15
by
laszlo
on 01 Apr, 2014 14:49
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Good article, stupid mission. Does not capture public imagination, will end up in the pile of powerpoints on the side of the road after the next budget cut.
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#16
by
newpylong
on 01 Apr, 2014 14:53
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A good update, but the article overstates a couple things:
One, the article's conclusion is overstated:
... NASA is aggressively pursuing to ARRM concept and has demonstrated that there are no technological roadblocks to implementation.
The key technologies necessary to implement this mission -- high-power SEP, the deep space rendezvous system, the capture mechanism, and the despin procedure -- have yet to be demonstrated at any level. High-level, generic analyses don't count as demonstrations. It's impossible to state at this time that there are "no technological roadblocks". Until we get further into actual development -- and possibly not until the mission is over -- will we know whether there are "no technological roadblocks" to ARM.
Two, the claims about planetary defense demonstrations in the article are also overstated:
Significantly, a planetary defense demo has been proposed for each of the mission concepts to prove out gravity tractor and/or ion beam deflection (IBD) concepts. For an object similar to 2009 BD (<500 tonne), a Δv of ~ 1mm/sec could be imparted in roughly 1 hr using IBD and about 30 hrs using gravity tractor.
These may be proofs-of-concept, but they are not "planetary defense demos". Too little energy is being imparted to too small a target with too much warning time. We could not take this system and divert an actual, dangerous NEO.
Again, a good update, but we should be careful when making absolute statements or making claims about supposed planetary defense capabilities.
Perhaps you are unfamiliar with the phrase, crawl, walk, run?
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#17
by
KEdward5
on 01 Apr, 2014 15:52
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Again, a good update, but we should be careful when making absolute statements or making claims about supposed planetary defense capabilities.
It's in the presentations. This is a write up of the presentations. I suggest you read them.
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#18
by
okan170
on 01 Apr, 2014 16:35
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If they wanted to pitch this to the public better, they should really play up the "planetary defense" aspect of the mission. Thats a fairly tangible goal that most people could see as a good use of time and energy and is much more easily relateable to everyday life than most of the rest of the goals of the mission.
Its technically an interesting and important mission, but its really misplaced I think. This is the sort of thing that should be like item number 5 on the list of things to sort out with BEO HSF and not the be-all end-all (or just the only) goal for the program. I mean ideally, it'd be a sort of demo mission for the capabilities developed, but who knows.
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#19
by
notsorandom
on 01 Apr, 2014 17:29
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Am I missing something or are we reaching a point when it might jsut be better to go out and visit an asteroid? Adding three years adds three more years worth of budget in addition to the $2 or so billion you save by not developing the retrieval element. That may be enough to develop a deep space mission/habitat module. The LUS will increase SLS's throw weight so much that two Block 1B launches will throw as much as three Block 1s to BEO. The 2021 SLS launch with the ICPS could still be used as a shake down cruse to check Orion and most of SLS out.
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#20
by
veblen
on 01 Apr, 2014 17:42
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Good article, stupid mission. Does not capture public imagination, will end up in the pile of powerpoints on the side of the road after the next budget cut.
Cute cat vids are popular. Kittys in micro-gravity would be hysterical and I dare say, "capture public imagination". Is that a good basis for designing space missions?
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#21
by
Space Ghost 1962
on 01 Apr, 2014 18:50
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Excellent article - head and shoulders better than any I've read on the subject.
Too bad it's apparently not being read by some of the posters critically but being reacted to. And one should read more of the supporting materials before responding with predictable "knee jerk" agendas. If the critical posts above carefully examine the article that was carefully written, they'll find it addresses the issues they bring up. I find that very annoying.
As I see it, the reason for this mission being separated from a SLS EM-2 (or other) is manifold - there are many political contradictions involved here that get dealt with all in one. That is the overriding consideration, and it's a smart one.
Few of you will agree with the reason SLS is being built - to provide a "credible threat" of doing human exploration beyond LEO such that at any time, any future "space race" that might be attempted, means that the US could adapt and respond in time to matter. We'll ignore the practical (and political) aspects that limit this pragmatism of which I have considerable doubt. Realize SLS does not have to be "used" but "useful". It actually helps that it is expensive, huge, and difficult to manage ... because only China and Russia would ever dare do something like it, and only then at a extreme cost.
The key problem with the prior mission involving SLS was that it confused a real exploration and capability development with this agenda, which must remain "pure" for political reasons. Among them is the ability to leave unresolved the deployment of SLS with its huge operational cost burdens. Remember, SLS is a strategic threat, not a tactical/operational capability.
In the past, such impurities were allowed. But now the fear is diversion of resources in
any form such that the agenda is potentially compelled in
any fashion. This is also why things appear so ridiculously impractical, and why so much antagonism results among those in these community - they have little to agree with unless its all one way.
We are moving into a more precarious world given recent events, and certain national security issues require a different posture than before. It is best to keep a tight definition on roles and need, irrespective of minor agendas being battled for by advocates.
Sooner or later you'll need to point SLS/Orion at something, and do some real science. Original EM-1/2 are embarrassing missions for NASA and are "impure" because of the contradictions that the guardians of purity have created for themselves.
This smart move allows them to exit the corner they've painted themselves into. Also, it means extending the beginnings of a defense capability started with the Deep Impact and Stardust missions as a US only research and development mission, albeit small scale. It also exposes the competitive aspect of all the players to respond, which leverage’s US economic and technological skills effectively.
Don't get distracted by the "noise" here - that a 100 meter asteroid isn't a 3,476,000 meter Moon. Listen to the "signal" - total control, access both human and robotic, by commercial industry and government science/military/other. Cheap by the standards of per square meter or ton of exploration.
Do we really know everything about
Morro Rock? Can we toss it around at kilometers/sec? Do we understand the geology, formation, volatiles, metals, etc of it?
Answer: No
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#22
by
yg1968
on 02 Apr, 2014 00:36
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Good article!
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#23
by
jongoff
on 02 Apr, 2014 02:08
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Have they considered a direct mechanical coupling, perhaps like Altius' "Sticky Boom" and/or a drill-like component to grasp onto the object and secure it to the spacecraft? This seems more feasible to scale up for a future planetary defense asteroid deflection system. The bag approach seems like a dead end in terms of scale.
I think different tools make sense at different scales. If you can be relatively sure that your target is solid rock, using something like the JPL microspines technology that they've been looking at, coupled with some arms (I'm partial to our boom technology but there is more than one way to skin a cat) makes a lot of sense. But if your target is a complete asteroid, that might be a rubble or even dust-pile, you're only going to bring it home with some variant on the bag concept (which provides very distributed forces and containment), or deflect it with a gravity tractor or their Ion Beam Deflection technique.
It was neat to see the details. We've worked with the JPL lab doing the microspines work.
Unfortunately for the BAA, they won't let proposers use NASA or JPL team members *or* technology. So microspines are out for proposers. But we have some ideas. I'm hoping to put in a proposal or two.
~Jon
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#24
by
jongoff
on 02 Apr, 2014 02:11
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Am I missing something or are we reaching a point when it might jsut be better to go out and visit an asteroid? Adding three years adds three more years worth of budget in addition to the $2 or so billion you save by not developing the retrieval element. That may be enough to develop a deep space mission/habitat module. The LUS will increase SLS's throw weight so much that two Block 1B launches will throw as much as three Block 1s to BEO. The 2021 SLS launch with the ICPS could still be used as a shake down cruse to check Orion and most of SLS out.
The problem is that Orion as-is doesn't have a heat shield that can survive return from most asteroids. The may be able to improve it a bit around the edges, but if they end up going to a new heat shield material (which is just about 100% guaranteed for Mars-return capability), requalifying that at this point could be really expensive. Orion and SLS just aren't good tools for BEO exploration. They might be ok for the Moon and the L-points, but they're the totally wrong tools for the job for other destinations. This isn't a slam on them--they were original designed with lunar missions in mind. The problem was when the mission changed, instead of recompeting the solutions, they just remarketed them, without actually making sure they had the required capabilities.
~Jon
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#25
by
jongoff
on 02 Apr, 2014 02:12
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Again, a good update, but we should be careful when making absolute statements or making claims about supposed planetary defense capabilities.
It's in the presentations. This is a write up of the presentations. I suggest you read them.
Yeah, the presentations were actually a lot of great detail. The JPL and Langley teams are no slouches. I think the concepts *can* be improved on, but they didn't leave a ton of low-hanging-fruit. :-)
~Jon
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#26
by
Proponent
on 02 Apr, 2014 15:37
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Am I missing something or are we reaching a point when it might jsut be better to go out and visit an asteroid?...
The problem is that Orion as-is doesn't have a heat shield that can survive return from most asteroids....
In addition, Laurie Garver mentioned in an interview shortly before leaving NASA that the doctors were not ready to approve a many-month BEO mission at this stage.
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#27
by
redliox
on 02 Apr, 2014 16:16
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Here's a thought applicable toward the boulder-retrieval version of ARM: could it pickup the Phobos "monolith"?
If I recall the load charts right, carbonaceous targets are the variety ARM can hoist the most with. I imagine this this would be toward the heavier end of even those limits, but outside of a boulder from Olympus Mons itself this thing would be an excellent consolation price to haul back from Mars.
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#28
by
Proponent
on 02 Apr, 2014 16:27
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Getting to Phobos and back would require quite a bit more time and delta-V than going to a carefully-selected NEA.
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#29
by
laszlo
on 02 Apr, 2014 16:42
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Good article, stupid mission. Does not capture public imagination, will end up in the pile of powerpoints on the side of the road after the next budget cut.
Cute cat vids are popular. Kittys in micro-gravity would be hysterical and I dare say, "capture public imagination". Is that a good basis for designing space missions?
For a purely commercial mission, yes. NASA, of course, is where the pre-commercial stuff is supposed to get done. Unfortunately, their funding comes from the public purse, so unless there's enough level of public engagement to get Congress' attention, missions will die, like Apollo did.
My concern is that this mission makes no sense. If you're going to robotically fetch a big rock, why leave it way out there where you then have to stage an expensive manned mission to have astronauts crawl all over it? Wouldn't it make more sense to bring it to the ISS? Or, since the mission has turned from exploration to studying rocks, why not just look at the pieces of asteroids that have voluntarily come to Earth?
Real manned asteroid exploration is getting into a spacecraft and going out to an asteroid. That's a mission that would get peoples' interest.
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#30
by
aero
on 02 Apr, 2014 18:15
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How much additional delta V would the system need to have in order to bring the asteroid back to the ISS instead of dropping it off at the current planned orbit? Would a refueling mission be enough extra prop to bring it down low.
After all, they are not talking about a big, dangerous asteroid. Of course I know it all depends on the mass of the captured asteroid.
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#31
by
metaphor
on 02 Apr, 2014 19:56
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How much additional delta V would the system need to have in order to bring the asteroid back to the ISS instead of dropping it off at the current planned orbit? Would a refueling mission be enough extra prop to bring it down low.
After all, they are not talking about a big, dangerous asteroid. Of course I know it all depends on the mass of the captured asteroid.
If not using aerocapture or aerobraking, it would take about 4000 m/s of delta-v to get to LEO. The spacecraft is designed to use about 200 m/s of delta-v from the time it captures an asteroid to lunar orbit. If the asteroid was 50 tons or less, the spacecraft might have enough delta-v to get to LEO. But it would be out of the question for a 500-ton asteroid (you would need a spacecraft 10 times bigger).
From an ISRU point of view, it makes no sense to drag the asteroid down the gravity well into LEO, only to have to go back out afterwards.
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#32
by
clongton
on 02 Apr, 2014 20:28
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Two related questions:
1. What is the expected SCIENCE return from this retrieval mission? Bringing back a rock to analyze does not really count because learning anything new about the rock beyond what spectral analysis shows is highly unlikely.
2. Assuming there is a real science return, is it worth it in terms of the cost of getting it?
I have yet to see this question directly answered.
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#33
by
notsorandom
on 02 Apr, 2014 20:30
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Am I missing something or are we reaching a point when it might jsut be better to go out and visit an asteroid?...
The problem is that Orion as-is doesn't have a heat shield that can survive return from most asteroids....
In addition, Laurie Garver mentioned in an interview shortly before leaving NASA that the doctors were not ready to approve a many-month BEO mission at this stage.
This would be in 2024, ten years from now. Several year long stints at ISS would have been completed. Also this would be ten years after EFT-1. Should be long enough to have figured the heat shield out.
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#34
by
Robotbeat
on 02 Apr, 2014 22:52
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Two related questions:
1. What is the expected SCIENCE return from this retrieval mission? Bringing back a rock to analyze does not really count because learning anything new about the rock beyond what spectral analysis shows is highly unlikely....
VERY untrue.
My former adviser does sample analysis on extra-terrestrial samples, and there is an enormous, ENORMOUS amount of other stuff you can do besides just spectral analysis. It's like saying you don't need to meet a person, just read their signature.
Extraterrestrial samples that come from a known asteroid are worth a lot scientifically, that's why we do sample return missions like OSIRIS-REx. That said, I asked him about whether he'd like 5 small samples (i.e. tens of grams) from 5 different targets versus 1 very big group of samples (100s of kg) from a single target, and he said he'd prefer the 5 different samples from 5 targets, although he had to think about it for a bit. Then again, he usually works with microscopic sample sizes. Others methods of study require larger samples. But still, OSIRIS-REx has a total cost of about $1 billion. If I had to guess, I'd say the asteroid return is probably worth a good two OSIRIS-RExes, so maybe about $2 billion. Not enough to justify the whole expense, but perhaps enough to justify the cost of the unmanned capture vehicle itself.
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#35
by
Remes
on 02 Apr, 2014 22:59
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1. What is the expected SCIENCE return from this retrieval mission? Bringing back a rock to analyze does not really count because learning anything new about the rock beyond what spectral analysis shows is highly unlikely.
The idea is, that some asteroids were created at the same time as our solar system. Therefore the content of the asteroid is very much the same as earth a few billion years ago. It would allow scientists to check their models, assumptions, understand formation of planets... it would allow science to understand what was earth based on the solar system and what parts on earth were brought in by impacting asteroids. So, even if it is a ball of dirt, it still can teach us a lot of the beginnings of the solar system, as this ball of dirt is some kind of snapshot. It's like digging ice cores in the antarktis to see, what earth's atmosphere was xyz years ago.
2. Assuming there is a real science return, is it worth it in terms of the cost of getting it?
Well, it depends on what scenario you choose. Rosetta, Hayabusa, Star Dust, ... I think every dollar/yen/euro was worth it. As we all know, the spacecraft flew to the asteroid. It's like understanding that, if someone wants a glass of milk, he doesn't need to bring the cow into his living room.
Some might say that an asteroid retrieval mission is like an asteroid collision avoidance training. Well, IMHO it would be enough to prove, that a given delta-v can be applied. Where this happens, doesn't matter.
In regards of HSF: for the sake of science there is zero added value if a human chops of some dirt from the asteroid. Zero! It increases cost dramatically (I guess by magnitudes). A geologist will have to look which part of the asteroid will be picked, but he can do that remote via TV. Really, sending humans to an asteroid is not done for science. There might be a need to drill a whole, but that can be done by machines and anyway: no one wants to have an Astronaut next to a sharp rotating tool in space.
Now there is SLS, and SLS is about humans in deep space. If people agree, that there is no benefit for science if humans do the work, that the costs are okay and it is mainly about training people, testing SLS, Orion, ... , than I guess the decission is made.
In terms of science, I think, it would be better to do sample return mission over a couple of different asteroid types. Samples must be examined on earth, only here the full spectrum of spectrometers and tests can be applied. An astronaut next to the Asteroid will do exactly 0.0 science.
I like to see science done on asteroids and I like to see SLS launch and humans in deep space. But combining these two will be hard to explain to the mass of people.
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#36
by
clongton
on 02 Apr, 2014 23:48
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But still, OSIRIS-REx has a total cost of about $1 billion. If I had to guess, I'd say the asteroid return is probably worth a good two OSIRIS-RExes, so maybe about $2 billion. Not enough to justify the whole expense, but perhaps enough to justify the cost of the unmanned capture vehicle itself.
But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
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#37
by
Vultur
on 03 Apr, 2014 01:47
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Am I missing something or are we reaching a point when it might jsut be better to go out and visit an asteroid?...
The problem is that Orion as-is doesn't have a heat shield that can survive return from most asteroids....
In addition, Laurie Garver mentioned in an interview shortly before leaving NASA that the doctors were not ready to approve a many-month BEO mission at this stage.
The problem with this is that unless we actually do it, it'll always be "at this stage" -- we've been messing around in LEO for decades supposedly to learn how to do BEO.
It's time to just develop the habitat, and DO IT. IMO.
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#38
by
Coastal Ron
on 03 Apr, 2014 02:16
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This would be in 2024, ten years from now. Several year long stints at ISS would have been completed. Also this would be ten years after EFT-1.
The first year-long mission at the ISS isn't planned to start until 2015. However what you appear to be assuming is that any issues that come up in the tests are able to be addressed and retested enough times to ensure that they have been solved. That might happen, but it might not. Depends on what they find, and it depends on how fast the solutions get funded, built, flown up to the ISS and the testing can be done. Lot of "ifs".
This is why assuming we're ready to pull the trigger on an HLV-based human exploration program is premature, since we have not yet figured out what our limits are for humans beyond 6-month stints in LEO.
Should be long enough to have figured the heat shield out.
As of today, with the heatshield that is not capable enough of coming back from locations beyond the Moon, the MPCV is overweight. At a NASA news conference last year (don't remember the date) NASA was asked when the MPCV weight issue would be solved, and NASA said they thought they would be fighting it up till the first crew launch (i.e. EM-2).
No doubt that could be addressed faster if more funding was made available, but then you'd have to throw in the additional funding to change out the heatshield for a more robust one. If a mission was identified that required the MPCV to return from beyond the Moon, I'm sure NASA would be identifying this issue as needing funding, but so far Congress and NASA haven't been discussing funding any missions at all beyond LEO. I'd rank it as a low probability at this point...
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#39
by
Coastal Ron
on 03 Apr, 2014 02:21
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Good article, stupid mission. Does not capture public imagination...
Does NASA have a requirement to "capture public imagination" with every mission it does? If so, does that mean that NASA is really just a form of government supplied entertainment?
Because if that's true, then I want to be able to vote for missions. And why not! Especially if the whole goal is to capture my imagination, AND they are using MY money to do it.
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#40
by
Robotbeat
on 03 Apr, 2014 02:54
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But still, OSIRIS-REx has a total cost of about $1 billion. If I had to guess, I'd say the asteroid return is probably worth a good two OSIRIS-RExes, so maybe about $2 billion. Not enough to justify the whole expense, but perhaps enough to justify the cost of the unmanned capture vehicle itself.
But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
Yeah, well then I agree. Not justifiable unless you're already counting SLS and Orion and all that enormous expense as a "sunk cost." May be possible as a public-private partnership or with using a Falcon Heavy + Dragon.
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#41
by
KelvinZero
on 03 Apr, 2014 08:44
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Two related questions:
1. What is the expected SCIENCE return from this retrieval mission? Bringing back a rock to analyze does not really count because learning anything new about the rock beyond what spectral analysis shows is highly unlikely.
2. Assuming there is a real science return, is it worth it in terms of the cost of getting it?
I have yet to see this question directly answered.
If pure science were the justification, which I infer from the capitalization, I would count that as a huge mark against it. Planetary Science already has a budget and a very detailed methodology for choosing missions.
I think it is really unfortunate that NASA cannot seem to do precursor missions because they neither fall into the camp of 'science', nor provide missions for SLS.
It is probably of very minor interest to science if NEOs contain useful volatiles or can be used for shielding, and this is also why we still have little idea if Phobos or Deimos could be used to provide propellant for return trips despite performing absurdly more difficult Mars mission, and why we have little interest in investigating the lunar poles to investigate the presence or not of water and/or hydrocarbons there before embarking on a highly expensive and specific multi-decade HSF architecture.
I think the science and HSF budgets should be kept totally separate, and the HSF budget should be for gaining the knowledge we need to colonize the solar system.
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#42
by
newpylong
on 03 Apr, 2014 13:27
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Two related questions:
1. What is the expected SCIENCE return from this retrieval mission? Bringing back a rock to analyze does not really count because learning anything new about the rock beyond what spectral analysis shows is highly unlikely.
2. Assuming there is a real science return, is it worth it in terms of the cost of getting it?
I have yet to see this question directly answered.
This was answered by Gerst in one interview. He said point blank they do not envision science as a primary goal of this mission.
You could consider any expenditures towards a science return a sunk cost.
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#43
by
truth is life
on 03 Apr, 2014 14:55
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But still, OSIRIS-REx has a total cost of about $1 billion. If I had to guess, I'd say the asteroid return is probably worth a good two OSIRIS-RExes, so maybe about $2 billion. Not enough to justify the whole expense, but perhaps enough to justify the cost of the unmanned capture vehicle itself.
But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
Well, it made more sense when it was going to be part of EM-2, hence also an engineering mission, where it would be a clever way to get some science in as well. Very much like the point of NEA rendezvous missions or Mars orbital missions, in fact, where the primary purpose is to test the spacecraft in a relevant environment and under realistic conditions, while having objectives that are less demanding than the "real" objectives you're after (ie., Mars). Here, it would mean that rather than just orbiting the Moon, which would have little value beyond engineering, you also get some nice science done as well.
With the switch to it not being EM-2, that justification has weakened...
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#44
by
Proponent
on 03 Apr, 2014 15:43
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How much additional delta V would the system need to have in order to bring the asteroid back to the ISS instead of dropping it off at the current planned orbit? Would a refueling mission be enough extra prop to bring it down low.
After all, they are not talking about a big, dangerous asteroid. Of course I know it all depends on the mass of the captured asteroid.
Assuming you could do a slingshot off the moon on the way in to kill off most of the speed at a lunar distance, the 'roid would be whizzing along at about escape speed (11 km/s) when it reached ISS's altitude. So the delta-V to circularize at that altitude would be at least 3-ish km/s, which is significant. And that's just a lower bound.
But a major justification for putting the asteroid in a stable lunar orbit was to ensure it didn't crash into earth if anything went wrong, so presumably bringing the 'roid to ISS is out of the question.
And a major justification for the whole thing is to give Orion a destination. If the 'roid delivers itself to ISS, there's no longer any need for Orion.
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#45
by
notsorandom
on 03 Apr, 2014 16:14
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This would be in 2024, ten years from now. Several year long stints at ISS would have been completed. Also this would be ten years after EFT-1.
The first year-long mission at the ISS isn't planned to start until 2015. However what you appear to be assuming is that any issues that come up in the tests are able to be addressed and retested enough times to ensure that they have been solved. That might happen, but it might not. Depends on what they find, and it depends on how fast the solutions get funded, built, flown up to the ISS and the testing can be done. Lot of "ifs".
This is why assuming we're ready to pull the trigger on an HLV-based human exploration program is premature, since we have not yet figured out what our limits are for humans beyond 6-month stints in LEO.
Should be long enough to have figured the heat shield out.
As of today, with the heatshield that is not capable enough of coming back from locations beyond the Moon, the MPCV is overweight. At a NASA news conference last year (don't remember the date) NASA was asked when the MPCV weight issue would be solved, and NASA said they thought they would be fighting it up till the first crew launch (i.e. EM-2).
No doubt that could be addressed faster if more funding was made available, but then you'd have to throw in the additional funding to change out the heatshield for a more robust one. If a mission was identified that required the MPCV to return from beyond the Moon, I'm sure NASA would be identifying this issue as needing funding, but so far Congress and NASA haven't been discussing funding any missions at all beyond LEO. I'd rank it as a low probability at this point...
All of the political players in space flight view Mars as the eventual goal. This means that long duration BEO spaceflight is a nut that has to be cracked sooner or later. There are cosmonauts that have in their careers received an equivalent radiation dose of a trip to Mars. We just don't have a big enough sample pool to retire the risk yet. Spending a year in space is doable and all that is required to get to a lot of the NEOs.
The heat shield thing is in the same basket. There may be a lot of margin in the design. We just don't know right now and are being conservative. Even if it requires work and money to fix it we will have to do it eventually. There are numerous good reasons why having the crew vehicle being able to enter directly from an Earth Mars transfer. By 2024 I don't think it is unrealistic to say that we will have a handle on both issues. After all if we don't by that time then Mars in the 2030s is a pipe dream.
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#46
by
Coastal Ron
on 03 Apr, 2014 16:46
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All of the political players in space flight view Mars as the eventual goal. This means that long duration BEO spaceflight is a nut that has to be cracked sooner or later.
Agreed. And doing the initial testing at the ISS makes a lot of sense since it can happen quicker and for a much lower cost than building new hardware. It doesn't address the radiation aspect, but that is only one of the factors anyways.
The point I was making, and maybe it wasn't worded right, is that there seems to be two approaches that can be taken.
One is to focus on the issues limiting us from longer duration HSF missions beyond LEO, and keep reassessing if we're ready to move out into space in a larger way. This is not unlike the capabilities-based planning that NASA is taking with the SLS and MPCV, but it would be based on not the transportation side but the payload side - are we ready to send humans beyond LEO for long durations? At some point our period assessments will tell us that we're either there are close enough to recommend that missions be approved. Call this a bottoms-up approach.
The other is to pick a date and hope that we can solve all the problems in time to make that date. The 2024 date seems like that kind of approach to me, especially since there is no defined need driving that date - it's just a date. If everything works out then the mission gets to go, but if things don't go as planned there is a whole lot of disconnected efforts that get thrown into disarray. Call this the top-down approach.
Without an agreed upon need, the top-down approach doesn't make sense, and it won't work because not everyone will be pushing to the same date, and there is likely to be a large funding mismatch. That's essentially what we have today.
The heat shield thing is in the same basket. There may be a lot of margin in the design. We just don't know right now and are being conservative.
I'm sure there is already a thread on this, and I'm not an engineer. But NASA agrees they have a major weight issue with the current specs and that it won't be solved for possibly 7 years. That doesn't sound like they have margin in the design.
Even if it requires work and money to fix it we will have to do it eventually.
Or re-evaluate what our future needs are and spend new money to build that. Let's remember that the MPCV is the product of a political process to "save" elements from the Moon-oriented Constellation program. If it is marginal for the Moon, why try to use it for beyond the Moon? I think we're already at the point that we need to be working on the next step in space transportation, which will have to be mostly reusable if we're ever going to afford to increase our presence in space.
After all if we don't by that time then Mars in the 2030s is a pipe dream.
It is a pipe dream. If we're struggling to meet up with a small rock just beyond the Moon in 10 years, why in the world would you think we'll be ready to go to Mars in another 10 years?
I'm not sure you understand how little NASA is able to do, and how much is needed to be done to get to Mars.
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#47
by
MP99
on 03 Apr, 2014 18:59
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... NASA is aggressively pursuing to ARRM concept and has demonstrated that there are no technological roadblocks to implementation.
The key technologies necessary to implement this mission -- high-power SEP, the deep space rendezvous system, the capture mechanism, and the despin procedure -- have yet to be demonstrated at any level. High-level, generic analyses don't count as demonstrations. It's impossible to state at this time that there are "no technological roadblocks". Until we get further into actual development -- and possibly not until the mission is over -- will we know whether there are "no technological roadblocks" to ARM.
Aren't those things which will be demonstrated *by* the mission?
cheers, Martin
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#48
by
veblen
on 03 Apr, 2014 19:44
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Good article, stupid mission. Does not capture public imagination, will end up in the pile of powerpoints on the side of the road after the next budget cut.
Cute cat vids are popular. Kittys in micro-gravity would be hysterical and I dare say, "capture public imagination". Is that a good basis for designing space missions?
For a purely commercial mission, yes. NASA, of course, is where the pre-commercial stuff is supposed to get done. Unfortunately, their funding comes from the public purse, so unless there's enough level of public engagement to get Congress' attention, missions will die, like Apollo did.
My concern is that this mission makes no sense. If you're going to robotically fetch a big rock, why leave it way out there where you then have to stage an expensive manned mission to have astronauts crawl all over it? Wouldn't it make more sense to bring it to the ISS? Or, since the mission has turned from exploration to studying rocks, why not just look at the pieces of asteroids that have voluntarily come to Earth?
Real manned asteroid exploration is getting into a spacecraft and going out to an asteroid. That's a mission that would get peoples' interest.
Well it has been discussed on this board the issue for a crew going out to an asteroid: Delta-v - asteroids are challenging targets. The ISS is not equipped to study a chunk of an asteroid.
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#49
by
KelvinZero
on 04 Apr, 2014 08:44
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Good article, stupid mission. Does not capture public imagination, will end up in the pile of powerpoints on the side of the road after the next budget cut.
Cute cat vids are popular. Kittys in micro-gravity would be hysterical and I dare say, "capture public imagination". Is that a good basis for designing space missions?
Man.. you are going to really regret not patenting that idea. LEOLOLCats.
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#50
by
Vultur
on 05 Apr, 2014 02:35
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Good article, stupid mission. Does not capture public imagination, will end up in the pile of powerpoints on the side of the road after the next budget cut.
Cute cat vids are popular. Kittys in micro-gravity would be hysterical and I dare say, "capture public imagination". Is that a good basis for designing space missions?
Man.. you are going to really regret not patenting that idea. LEOLOLCats.
Possibly deserves its own thread
This would be in 2024, ten years from now. Several year long stints at ISS would have been completed. Also this would be ten years after EFT-1.
The first year-long mission at the ISS isn't planned to start until 2015. However what you appear to be assuming is that any issues that come up in the tests are able to be addressed and retested enough times to ensure that they have been solved. That might happen, but it might not. Depends on what they find, and it depends on how fast the solutions get funded, built, flown up to the ISS and the testing can be done. Lot of "ifs".
This is why assuming we're ready to pull the trigger on an HLV-based human exploration program is premature, since we have not yet figured out what our limits are for humans beyond 6-month stints in LEO.
Well, humans have spent much more than 6 months in LEO -- record is over 14 months (
http://en.wikipedia.org/wiki/Valeri_Polyakov )
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#51
by
A_M_Swallow
on 05 Apr, 2014 17:46
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But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
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#52
by
IRobot
on 05 Apr, 2014 21:25
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But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.
Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.
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#53
by
A_M_Swallow
on 06 Apr, 2014 02:00
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But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.
Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.
If you are doing a reentry the EML-1 to Earth surface delta-v is about 0.77 km/s.
The inspace stage could be launched separately from the Orion and the pair dock in orbit.
The quantity of thrust needed to push the spacecraft to EML-1 and for how long the burn is may determine if an existing engine (or group of engines) can be used or cause a new engine to be designed.
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#54
by
newpylong
on 06 Apr, 2014 15:47
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But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.
Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.
How are they going to get home if Orion uses its Main engine for T-EML1 injection? That burn needs to be achieved using a cryogenic stage.
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#55
by
A_M_Swallow
on 07 Apr, 2014 02:10
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But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.
Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.
How are they going to get home if Orion uses its Main engine for T-EML1 injection? That burn needs to be achieved using a cryogenic stage.
To perform the return burn the Orion needs a main engine that can be restarted inspace whose propellant is space storable such as LOX/methane. A medium sized Isp just means that the tanks have to be big. Fortunately nearly empty fuel tanks are light.
The quantity of thrust needed to push the spacecraft to EML-1 and for how long the burn is may determine if an existing engine (or group of engines) can be used or cause a new engine to be designed.
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#56
by
Robert Thompson
on 07 Apr, 2014 08:17
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"...the principle of construction of Makarov’s cable networks can be the basis for creating a huge space platform. On such a platform, a solar reflector could be placed that directs concentrated sunlight to the asteroid Apophis in order to change its trajectory. This will prevent it from colliding with Earth in 2029."
http://www.spacesafetymagazine.com/2014/04/04/modern-dreams-sky-earth/
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#57
by
newpylong
on 07 Apr, 2014 10:48
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But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.
Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.
How are they going to get home if Orion uses its Main engine for T-EML1 injection? That burn needs to be achieved using a cryogenic stage.
To perform the return burn the Orion needs a main engine that can be restarted inspace whose propellant is space storable such as LOX/methane. A medium sized Isp just means that the tanks have to be big. Fortunately nearly empty fuel tanks are light.
The quantity of thrust needed to push the spacecraft to EML-1 and for how long the burn is may determine if an existing engine (or group of engines) can be used or cause a new engine to be designed.
Ya didn't get what I meant. If the Orion SPS is used to get out of earth orbit it will most likely not have enough propellant to make the return burn.
It does have storable propellant and a restartable main engine.
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#58
by
A_M_Swallow
on 07 Apr, 2014 20:47
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Ya didn't get what I meant. If the Orion SPS is used to get out of earth orbit it will most likely not have enough propellant to make the return burn.
It does have storable propellant and a restartable main engine.
Then the Orion Service Module will either need larger fuel tanks for the return trip to EML-1 or to refuel. The extra work and cost of handling the fuel will need planning in.
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#59
by
Jim
on 07 Apr, 2014 23:19
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Then the Orion Service Module will either need larger fuel tanks for the return trip to EML-1 or to refuel. The extra work and cost of handling the fuel will need planning in.
No, neither are in the plans
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#60
by
newpylong
on 08 Apr, 2014 01:19
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Ya didn't get what I meant. If the Orion SPS is used to get out of earth orbit it will most likely not have enough propellant to make the return burn.
It does have storable propellant and a restartable main engine.
Then the Orion Service Module will either need larger fuel tanks for the return trip to EML-1 or to refuel. The extra work and cost of handling the fuel will need planning in.
Why? If it happens at all it's going straight there on an SLS upper stage, just like Apollo on the S-IVB. It only needs it SPS to get home.
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#61
by
A_M_Swallow
on 08 Apr, 2014 07:55
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Why? If it happens at all it's going straight there on an SLS upper stage, just like Apollo on the S-IVB. It only needs it SPS to get home.
Only if the SLS is still around. Clongton was asking about using a different LV such as a Falcon Heavy.
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#62
by
A_M_Swallow
on 08 Apr, 2014 07:58
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Then the Orion Service Module will either need larger fuel tanks for the return trip to EML-1 or to refuel. The extra work and cost of handling the fuel will need planning in.
No, neither are in the plans
I had guessed that. I suspect using a Delta IV Heavy instead of the SLS is not in the current plans either.
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#63
by
Robert Thompson
on 18 Apr, 2014 18:43
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http://phys.org/news/2014-04-astronauts-reveal-sobering-asteroid-impacts.html"... This network has detected 26 multi-kiloton explosions since 2001, all of which are due to asteroid impacts. It shows that asteroid impacts are NOT rare—but actually 3-10 times more common than we previously thought. The fact that none of these asteroid impacts shown in the video was detected in advance is proof that the only thing preventing a catastrophe from a 'city-killer' sized asteroid is blind luck. ..."
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#64
by
A_M_Swallow
on 18 Apr, 2014 19:20
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http://phys.org/news/2014-04-astronauts-reveal-sobering-asteroid-impacts.html
"... This network has detected 26 multi-kiloton explosions since 2001, all of which are due to asteroid impacts. It shows that asteroid impacts are NOT rare—but actually 3-10 times more common than we previously thought. The fact that none of these asteroid impacts shown in the video was detected in advance is proof that the only thing preventing a catastrophe from a 'city-killer' sized asteroid is blind luck. ..."
26 multi-kiloton explosions without any one being killed seems very lucky.
26/(2014 - 2001 + 1) = 1.86 about 2 asteroids a year
