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#220
by
MATTBLAK
on 08 Jan, 2015 01:34
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As a contingency against SLS cancellation - I believe Block I should be 20 ton class and Block II, 50 ton class. The 50 ton class - arrays, structure, thrusters, avionics and propellant - would have formidable capability. There is much potential for lightweight and efficient arrays including gallium arsenide cell or even 3D printed next generation silicon cells.
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#221
by
jongoff
on 08 Jan, 2015 02:16
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FWIW, we were given permission today to do a follow-the-build blog series on our Kraken Asteroid Boulder Retrieval System prototype that we're getting paid to develop under our ARM BAA Phase 1. We'll probably start that up later this week or early next week. It's not the NASA-official ARM project, but still should be a lot of fun. I'll post a link when we get started. I'll also mention this over on the Altius thread.
~Jon
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#222
by
MP99
on 08 Jan, 2015 09:54
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ISTM that for a realistic test of ISRU you'd want a representative sample, but that's not possible once you pluck a boulder away from any dust / rubble surrounding it?
Both the Altius and MDA Option B concepts involved some sort of system for removing and collecting the dust from the boulder (and its immediate environs). Altius using an electrodynamic dust collection system, MDA using Honeybee's pneumatic excavation concept. But yeah, getting the boulder "in context" with the dust that was on/around it is probably very useful from a scientific/engineering standpoint.
~Jon
Thanks, hadn't appreciated that.
Cheers, Martin
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#223
by
MP99
on 08 Jan, 2015 10:04
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5- I can't remember where I saw it publicly, but apparently one of the potential uses for the commercial-derived Hab module that NASA's studying under the NextSTEP BAA was to provide a hab module at the ARM asteroid sample to enable longer-duration exploration and study of the asteroid sample, and to demonstrate long-duration habitation at some place close enough you could safely make it home if something goes wrong. This would basically create a tiny man-tended NEO-lab in lunar orbit (that could also serve as a lunar gateway).
I just think that so many of the naysayers have such a limited view of what's going on. Admittedly NASA hasn't provided a ton of clarity on exactly what they're trying to do, probably since they're trading two so very different options, but I hope that will continue to change in the 1st quarter of this new year.
I still think this is NASA's way of avoiding doing the hard stuff on the flexible path to Mars.
But, as a ray of hope, I've always thought we should get a DSH / MTV prototype out to EML (or now DRO), and start getting the hours on it to prove it for more distant missions.
Cheers, Martin
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#224
by
Hop_David
on 08 Jan, 2015 15:25
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I still think this is NASA's way of avoiding doing the hard stuff on the flexible path to Mars.
NASA isn't going to colonize Mars.
To establish substantial space infrastructure there has to be a financial incentive. It's possible asteroid mining could provide that incentive.
Developing a Keck style retrieval vehicle could be helpful to entities like Planetary Resources or Deep Space Industries. And a profitable asteroid mining company might be a way for humanity to get its foot in the door. Should asteroid mining become profitable, extensive space infrastructure would occur as a matter of course. Given gradually expanding space infrastructure, humanity's sphere of influence could eventually include Mars.
And what is the "flexible path" you speak of? Here is some breaking news: Our elected officials don't give a hoot for space settlement. All they want are vague goals over the next horizon to justify pork barrel jobs programs. The political weather vane spins too often for a sustained, well supported Mars program. Mars colonization via NASA is a sure recipe to squander billions, accomplishing nothing but alienating tax paying voters.
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#225
by
MP99
on 08 Jan, 2015 20:56
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Mars justifies SLS / Orion, which justifies ARRM. NASA has a tightwire to walk to avoid admitting what's really both our points - that this is just pretending they're making good progress towards SLS taking people to Mars.
Cheers, Martin
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#226
by
enkarha
on 09 Jan, 2015 10:40
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The main point is opening up opportunities to demonstrate technology, in the present and the future, and doing something new meanwhile. Fits right in with Obama's space policy. Hasn't this always been the case?
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#227
by
arachnitect
on 09 Jan, 2015 17:17
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Mars justifies SLS / Orion, which justifies ARRM. NASA has a tightwire to walk to avoid admitting what's really both our points - that this is just pretending they're making good progress towards SLS taking people to Mars.
Cheers, Martin
On that note, they just embarrassed themselves yesterday (courtesy of spacenews):
WASHINGTON — A NASA official on Jan. 7 offered one of the clearest reminders yet that the agency’s proposed Asteroid Redirect Mission (ARM) is more about technology development than actually sending a small asteroid to lunar orbit to be visited by astronauts next decade.
After a presentation in Phoenix to the NASA-chartered Small Bodies Assessment Group (SBAG), Lindley Johnson, head of the agency’s Near Earth Object Observations Program, said redirecting an asteroid to a distant retrograde orbit around the Moon is “not the top objective of the [ARM] mission,” which was trotted out in spring 2013 as a means to road test technology needed for a crewed Mars expedition and provide — in the form of the titular asteroid — a near-term destination for the Space Launch System rocket and Orion crew capsule NASA is building.
- See more at: http://spacenews.com/redirecting-asteroid-not-top-objective-of-asteroid-redirect-mission-nasa-official-says/#sthash.mkUzz7Jx.dpuf
.........................
That technology gibberish was the same line tooted for the shuttle in the '80s.
Further quoting...
Asteroid redirection has dominated public discussion of ARM, both in the press and the halls of Congress, since NASA unveiled the proposed mission with great fanfare almost two years ago.
Yet now, according to Johnson, NASA may not even make redirection of a boulder or asteroid a requirement for mission success. Pressed by SBAG member Mark Sykes, director of the Planetary Science Institute in Tucson, Arizona, on whether a mission concept review scheduled for Feb. 26 would cement redirection as an ARM requirement, Johnson said no.
Redirecting an asteroid “is certainly something that the agency as a whole wants to do with the mission, but to a certain level, objectives are tradable,” Johnson said.
Sykes, a veteran planetary scientist, scoffed at that answer in a Jan. 7 Twitter post, asking rhetorically, “then what is the point?”
- See more at: http://spacenews.com/redirecting-asteroid-not-top-objective-of-asteroid-redirect-mission-nasa-official-says/#sthash.mkUzz7Jx.dpuf
I've officially gone from being merely speculative about ARM to being depressed about it. If this is the kind of language they use before Congress it may as well be carved onto a tombstone. I dare say this would be enough to kill ARM even before Obama steps down from office!
If anyone hears details about this meeting for the small bodies committee post it asap. It already feels like a swift change is blowing in.
I think people are being too timid about it. I think ARM really actually has some things going for it, but all ideas -good or bad- need advocates to succeed.
Ramp up the asteroid search component. There's a chance here to do something for the vocal yet politically weak asteroid mining and planetary defense communities... get them on board. Get a real Phobos/Deimos architecture out there and point out how ARM is important to that.
Stop calling it "technology demonstration" start calling "Like Gemini, but for a mars mission."
I feel like people are
trying to be unexcited about a space mission because it doesn't exactly match their personal vision. That depresses me.
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#228
by
ehb
on 09 Jan, 2015 17:26
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Mars justifies SLS / Orion, which justifies ARRM. NASA has a tightwire to walk to avoid admitting what's really both our points - that this is just pretending they're making good progress towards SLS taking people to Mars.
Cheers, Martin
On that note, they just embarrassed themselves yesterday (courtesy of spacenews):
WASHINGTON --
(snip)
Yet now, according to Johnson, NASA may not even make redirection of a boulder or asteroid a requirement for mission success. Pressed by SBAG member Mark Sykes, director of the Planetary Science Institute in Tucson, Arizona, on whether a mission concept review scheduled\
for Feb. 26 would cement redirection as an ARM requirement, Johnson said no.
Redirecting an asteroid "is certainly something that the agency as a whole wants to do with the mission, but to a certain level, objectives are tradable," Johnson said.
Sounds to me like they are positioning themselves for Option B.
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#229
by
redliox
on 09 Jan, 2015 19:28
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I think people are being too timid about it. I think ARM really actually has some things going for it, but all ideas -good or bad- need advocates to succeed.
Ramp up the asteroid search component. There's a chance here to do something for the vocal yet politically weak asteroid mining and planetary defense communities... get them on board. Get a real Phobos/Deimos architecture out there and point out how ARM is important to that.
Not really if your objective is getting to Mars or the Moon. The SEP aspects may be useful for enhancing the cargo element of an expedition, but the excessive weight of solar arrays and the r&d become a combination of a 5th wheel, white elephant, and budget cut target. It's too slow in acceleration to do much in the ~6 months the human leg of a flight would need. If you want results on a budget it's best to stick with chemical and Hohfman transfer.
I'd love a Phobos/Deimos element, but I think in the end you'd only need a hab module with an airlock opposite Orion's end and a smaller version of a manned maneuver unit. If landing is needed just add light landing struts. Testing for regolith conditions would be wise, but beyond that the lack of gravity makes it child's play.
Stop calling it "technology demonstration" start calling "Like Gemini, but for a mars mission."
I feel like people are trying to be unexcited about a space mission because it doesn't exactly match their personal vision. That depresses me.
Well here's the deal: the whole asteroid idea was thrown because NEOs could be reached and returned from within a year's time, so long as you identified one easy to predict. A single year to an object beyond the Moon yet within Earth's reach, as a precursor to Mars, is what got space people initially behind it. Problem: Orion by itself can barely fly for a month and they don't know how to fully rad-proof it; that prompted dragging the asteroid to us instead. From the crew and (would be Martian) hardware perspective you're just redoing a Moon flight.
Btw, NASA is the only one calling it a technology demonstration at this point. Everyone else is calling it nonsense.
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#230
by
A_M_Swallow
on 09 Jan, 2015 20:15
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So this is a technology test flight pretending to be an operational flight. By combining the two NASA presumably hopes to save time and money. If it does not work NASA may have to go back to Congress for more money.
Producing an operational SEP tug would be a very successful development project, and is worth the cost of the entire program. Getting the asteroid is a bonus.
As well as taking capture bags to asteroids SEP tugs can take cargo to lunar orbit and Mars orbit. SEP tugs may be slower than chemical rocket tugs but they can carry heavier cargoes.
The press will need a way of marking the spacecraft as it passes each part of the test. I suggest a handout containing a three column table - item number, pass/fail and name of item. As each item passes the PA tells the journalists it passed.
edit : grammar
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#231
by
TrevorMonty
on 09 Jan, 2015 20:22
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#232
by
arachnitect
on 09 Jan, 2015 23:13
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Not really if your objective is getting to Mars or the Moon. The SEP aspects may be useful for enhancing the cargo element of an expedition, but the excessive weight of solar arrays and the r&d become a combination of a 5th wheel, white elephant, and budget cut target. It's too slow in acceleration to do much in the ~6 months the human leg of a flight would need. If you want results on a budget it's best to stick with chemical and Hohfman transfer.
Nothing says "affordable" like 12 Ares V launches (DRM 5.0 chemical option).
Btw, NASA is the only one calling it a technology demonstration at this point. Everyone else is calling it nonsense.
Sending hungry thirsty gasping delicate humans out into deep space is fundamentally nonsense, but a whole bunch of people say we should be doing it. Okay then, what makes "more sense," but fits the budget and SLS' capabilities (The SLS we're gonna get, and its one pad)? The "Inspiration Mars"
suicide fly by mission? A lonely station at earth-moon L2? The alternative to ARM isn't a 4 person lunar south pole mission with a rover... it's a top line budget cut and a BEO program that ends after EM-1.
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#233
by
Nilof
on 09 Jan, 2015 23:38
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I think people are being too timid about it. I think ARM really actually has some things going for it, but all ideas -good or bad- need advocates to succeed.
Ramp up the asteroid search component. There's a chance here to do something for the vocal yet politically weak asteroid mining and planetary defense communities... get them on board. Get a real Phobos/Deimos architecture out there and point out how ARM is important to that.
Not really if your objective is getting to Mars or the Moon. The SEP aspects may be useful for enhancing the cargo element of an expedition, but the excessive weight of solar arrays and the r&d become a combination of a 5th wheel, white elephant, and budget cut target. It's too slow in acceleration to do much in the ~6 months the human leg of a flight would need. If you want results on a budget it's best to stick with chemical and Hohfman transfer.
I'd love a Phobos/Deimos element, but I think in the end you'd only need a hab module with an airlock opposite Orion's end and a smaller version of a manned maneuver unit. If landing is needed just add light landing struts. Testing for regolith conditions would be wise, but beyond that the lack of gravity makes it child's play.
You'd need quite a lot more than that. To get anywhere near Mars with chemical, you'll need a very large transfer stage. Unless you are Mars one, you'll also need an Earth return stage. For capture, unless you're willing to perform a huge capture burn you'll need to develop a huge heat shield for areocapture.
If you want to use any cryogenic fuels, you need a large depot, because we are not anywhere close to being capable of launching half a dozen super-heavy launchers in rapid succession. If you use storable fuels, your mass ratio explodes.
So is there a technology that can get rid of depots, that only uses easily storable propellants, which does not explode your mass fraction and which eliminates the need for a massive heat shield for anything but a potential lander? SEP is the only option I can think of here. If you want to do anything better than a Mars flyby, it is actually the option that would require the least R&D when you consider the full array of technologies needed to support a chemical-only mission.
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#234
by
savuporo
on 10 Jan, 2015 02:34
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So is there a technology that can get rid of depots, that only uses easily storable propellants, which does not explode your mass fraction and which eliminates the need for a massive heat shield for anything but a potential lander?
Fission.
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#235
by
Vultur
on 10 Jan, 2015 04:24
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Not really if your objective is getting to Mars or the Moon. The SEP aspects may be useful for enhancing the cargo element of an expedition, but the excessive weight of solar arrays and the r&d become a combination of a 5th wheel, white elephant, and budget cut target. It's too slow in acceleration to do much in the ~6 months the human leg of a flight would need. If you want results on a budget it's best to stick with chemical and Hohfman transfer.
Nothing says "affordable" like 12 Ares V launches (DRM 5.0 chemical option).
Btw, NASA is the only one calling it a technology demonstration at this point. Everyone else is calling it nonsense.
Sending hungry thirsty gasping delicate humans out into deep space is fundamentally nonsense,
By whose standard? People could have said the same thing about exploring Antarctica 100 years ago, but we still have scientific stations there. Or about the deep sea, but we still have submarines.
And it's only even as difficult as it is because no one's really done the work for a sensible long term life support system. I think you could make a pretty fully closed system at a surprisingly small mass if you incorporated algae and stuff.
Okay then, what makes "more sense," but fits the budget and SLS' capabilities (The SLS we're gonna get, and its one pad)?
Mission to an asteroid in its own orbit, contract Bigelow to build a small hab module since that's beyond the time Orion can last with its own supplies.
The "Inspiration Mars" suicide fly by mission?
It's nowhere near suicidal. Risky, yes, but much less so than most historical exploration on Earth IMO. With SLS you wouldn't even need fancy ECLSS, 500 days' supplies for 2 people aren't THAT much mass. As long as you have enough shielding in the capsule/shelter that solar flares aren't fatal, radiation isn't that big of a deal - it adds cancer risk but so do lots of things we do.
(I actually think a 1 person version might be safer - the risk of violence with 2 people is probably higher than the risk of 1 person getting dangerously sick in an environment with no external source of pathogens, assuming good medical screening and quarantine before leaving Earth.)
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#236
by
savuporo
on 10 Jan, 2015 04:58
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Sending hungry thirsty gasping delicate humans out into deep space is fundamentally nonsense,
And it's only even as difficult as it is because no one's really done the work for a sensible long term life support system. I think you could make a pretty fully closed system at a surprisingly small mass if you incorporated algae and stuff.
For anyone believing for some irrational reason that human spaceflight to interplanetary distances is blocked by just one single little problem like having bigger rockets or having a closed loop life support system, i really really encourage reading
Donald Rapp's book :
http://www.thespacereview.com/article/1082/1. In Human Missions to Mars: Enabling Technologies for Exploring the Red Planet, Dr. Donald Rapp puts forth what he calls a skeptic’s view on the realities of sending a human mission to Mars in the 21st century. Rapp, retired chief technologist at the Jet Propulsion Laboratory, closely examines the technological aspects of mounting a human mission to Mars. To give you some idea of the scope and detail of the subjects covered in this book, the table of contents alone is nearly ten pages.
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#237
by
Nilof
on 10 Jan, 2015 09:41
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So is there a technology that can get rid of depots, that only uses easily storable propellants, which does not explode your mass fraction and which eliminates the need for a massive heat shield for anything but a potential lander?
Fission.
NTR does not fulfill three of the four conditions I mentioned. It significantly complicates operations such as dockings by making the space around the craft deadly except for a small cone behind the shadow shield. Furthermore, if it's supposed to do anything beyond the initial transfer burn, you'll need to develop lightweight storage of liquid hydrogen for months to years. And even though it has very high per-craft costs, it is very difficult to reuse since you won't get permission to areobrake it in Earth's atmosphere on the return trip.
In the case of NEP, solar arrays have a much better specific power in the inner solar system. That and it'd be rather stupid to replace SEP with an equivalent nuclear powered system if your objection to SEP was cost. You lose reliabillity by switching from a system with no moving parts to a complex thermodynamic cycle, ignoring the complexities associated with the nuclear fuel itself. There hasn't even been
a year 24 hours since the last ISS cooling fluid leak. Now imagine having to fix that right next to an active reactor.
EDIT: of course a coolant loop had to happen again on the ISS right after I wrote the original post.
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#238
by
Vultur
on 10 Jan, 2015 18:16
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Sending hungry thirsty gasping delicate humans out into deep space is fundamentally nonsense,
And it's only even as difficult as it is because no one's really done the work for a sensible long term life support system. I think you could make a pretty fully closed system at a surprisingly small mass if you incorporated algae and stuff.
For anyone believing for some irrational reason that human spaceflight to interplanetary distances is blocked by just one single little problem like having bigger rockets or having a closed loop life support system, i really really encourage reading Donald Rapp's book : http://www.thespacereview.com/article/1082/1
. In Human Missions to Mars: Enabling Technologies for Exploring the Red Planet, Dr. Donald Rapp puts forth what he calls a skeptic’s view on the realities of sending a human mission to Mars in the 21st century. Rapp, retired chief technologist at the Jet Propulsion Laboratory, closely examines the technological aspects of mounting a human mission to Mars. To give you some idea of the scope and detail of the subjects covered in this book, the table of contents alone is nearly ten pages.
I don't think it's blocked by
anything except money and political will. The Russians have demonstrated human spaceflight for over a year in LEO; the only difference BEO is radiation which is either easy to deal with (solar flares) or unimportant (GCRs).
Larger rockets aren't necessary, they just reduce the number of launches.
Closed-loop life support isn't necessary, it just reduces the mass needed.
Mars specifically adds more undemonstrated steps due to EDL of large payloads and ascent, but Mars isn't the only destination. Lunar landing and ascent are demonstrated, and NEOs have such weak gravity that it's a rendezvous rather than a landing.
EDIT: I'm pessimistic about NASA's approach too, but that's because they're way too risk-averse and insist on unnecessary difficulties like GCR protection and really huge mass in LEO. (My favored version is some kind of Mars Direct, except without the unnecessary spinning-for-artificial-gravity).
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#239
by
Solman
on 12 Jan, 2015 23:08
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So is there a technology that can get rid of depots, that only uses easily storable propellants, which does not explode your mass fraction and which eliminates the need for a massive heat shield for anything but a potential lander?
Fission.
Solar thermal/electric.
Solar thermal using hydrogen for LEO to escape and then using the concentrator to provide electricity by moving concentrator type PV into the focus. SEP after that perhaps MPD using lithium and then perhaps solar thermal using lithium or lithium hydride modified to add: for the final thrust to brake to Mars orbit because of its higher thrust.
Faster than NTP or NEP, low cost, highly efficient and no depots needed. Once at Mars orbit the concentrator PV electric power is available for power beaming by microwave or laser.
I'm a fan of aerocapture but SEP with aerobraking is perhaps a good alternative.