Quote from: Robotbeat on 09/25/2016 05:45 pmProducing water from the air is similar to later methods (getting it from regolith or dirty ice) & is simple enough to put on an early mission.Heck, a small scoop that gets some regolith and extracts some water from it also would be even more similar. Not too different than some of the instruments on Viking or MSL, but simpler.Which again isn't at all useful for anything more than a stunt, since you'll obtain minute quantities of water from whatever a small scoop can gather (assuming SpaceX would even try to engineer such a thing for a Red Dragon demo mission). From that minute few droplets of water, you'll get ... how much methane exactly? Silly waste of resources to devote that much power, mass, and software development for such a useless activity.
Producing water from the air is similar to later methods (getting it from regolith or dirty ice) & is simple enough to put on an early mission.Heck, a small scoop that gets some regolith and extracts some water from it also would be even more similar. Not too different than some of the instruments on Viking or MSL, but simpler.
Quote from: Phil Stooke on 09/25/2016 06:27 pmNot a stunt, a demonstration, a proof of concept. Make it work, measure results, feed back into planning for the next time. What would you prefer in its place? It's not useful to just say no to something, say what you would prefer to be done.Is there a real need for a payload on the 1st flight anyway? Mars EDL is the primary objective, a huge accomplishment if successful. It may be worth it to forgo the payload to save mass for EDL.
Not a stunt, a demonstration, a proof of concept. Make it work, measure results, feed back into planning for the next time. What would you prefer in its place? It's not useful to just say no to something, say what you would prefer to be done.
Even extracting the water from the atmosphere is not helpful in that respect as it cannot yield the amounts of water for fuel ISRU and supplying a base later. ... Only producing the water in the same way that will be needed for ISRU later is going to give really useful data. Everything else is more PR.
Water has other uses than ISRU.
But, I'd want a back-up water supply using an entirely separate process, and there may be a need to produce water in small quantities using compact equipment; perhaps in satellite habitats or on long-range rovers?In general, I'm suspicious of the idea that there is one 'best' way to do anything. Especially in a new environment, diversity is a strength and safeguard.
TL/DR: the payload for this flight should, imo, be a payload management and deployment system
Which again isn't at all useful for anything more than a stunt, since you'll obtain minute quantities of water from whatever a small scoop can gather (assuming SpaceX would even try to engineer such a thing for a Red Dragon demo mission). From that minute few droplets of water, you'll get ... how much methane exactly? Silly waste of resources to devote that much power, mass, and software development for such a useless activity.
Quote from: guckyfan on 09/25/2016 05:06 pmEven extracting the water from the atmosphere is not helpful in that respect as it cannot yield the amounts of water for fuel ISRU and supplying a base later. ... Only producing the water in the same way that will be needed for ISRU later is going to give really useful data. Everything else is more PR.Water has other uses than ISRU. Granted, any process to produce water in the quantities needed for ISRU will likely also produce the water for other purposes. But, I'd want a back-up water supply using an entirely separate process, and there may be a need to produce water in small quantities using compact equipment; perhaps in satellite habitats or on long-range rovers?In general, I'm suspicious of the idea that there is one 'best' way to do anything. Especially in a new environment, diversity is a strength and safeguard.
Quote from: CuddlyRocket on 09/25/2016 09:07 pmQuote from: guckyfan on 09/25/2016 05:06 pmEven extracting the water from the atmosphere is not helpful in that respect as it cannot yield the amounts of water for fuel ISRU and supplying a base later. ... Only producing the water in the same way that will be needed for ISRU later is going to give really useful data. Everything else is more PR.Water has other uses than ISRU. Granted, any process to produce water in the quantities needed for ISRU will likely also produce the water for other purposes. But, I'd want a back-up water supply using an entirely separate process, and there may be a need to produce water in small quantities using compact equipment; perhaps in satellite habitats or on long-range rovers?In general, I'm suspicious of the idea that there is one 'best' way to do anything. Especially in a new environment, diversity is a strength and safeguard.First of all, I'd challenge the claim that air reclamation of water can't yield enough water. It certainly can! But the same technique could be used for extracting water from ice or regolith, it's just that you would heat the regolith/ice first in a sealed enclosure and your yield would be MUCH higher. But the techniques are basically the same. Or could be, depending on exactly what approach you take.
Quote from: Phil Stooke on 09/25/2016 06:27 pmNot a stunt, a demonstration, a proof of concept. Make it work, measure results, feed back into planning for the next time. We can do that on Earth in a lab or an environment chamber filled with CO2 and a floor covered in iron-rich soil, perchlorate salts and a tiny bit of water. In fact, it HAS been done that way.
Not a stunt, a demonstration, a proof of concept. Make it work, measure results, feed back into planning for the next time.
QuoteWhat would you prefer in its place? The mass/power/data required for an ISRU stunt to be devoted to longer surface life, more/higher fidelity data recording from the powered EDL phases of flight, longer surface life, or basically anything else.
What would you prefer in its place?
QuoteIt's not useful to just say no to something ...When one has engineering experience and knowledge relevant to the discussion and knows the relatively tiny payoff for a stunt compared to how much effort and spacecraft resources necessary to carry it out, it certainly *IS* useful.
It's not useful to just say no to something ...
Quote from: Robotbeat on 09/25/2016 10:15 pmQuote from: CuddlyRocket on 09/25/2016 09:07 pmQuote from: guckyfan on 09/25/2016 05:06 pmEven extracting the water from the atmosphere is not helpful in that respect as it cannot yield the amounts of water for fuel ISRU and supplying a base later. ... Only producing the water in the same way that will be needed for ISRU later is going to give really useful data. Everything else is more PR.Water has other uses than ISRU. Granted, any process to produce water in the quantities needed for ISRU will likely also produce the water for other purposes. But, I'd want a back-up water supply using an entirely separate process, and there may be a need to produce water in small quantities using compact equipment; perhaps in satellite habitats or on long-range rovers?In general, I'm suspicious of the idea that there is one 'best' way to do anything. Especially in a new environment, diversity is a strength and safeguard.First of all, I'd challenge the claim that air reclamation of water can't yield enough water. It certainly can! But the same technique could be used for extracting water from ice or regolith, it's just that you would heat the regolith/ice first in a sealed enclosure and your yield would be MUCH higher. But the techniques are basically the same. Or could be, depending on exactly what approach you take.And again ... how do you integrate this stuff into a Red Dragon mission and how do you justify the proportionally gigantic share of the power, mass and data budget to justify it? That's the question no one has an answer for. Continuing to avoid it doesn't make it go away.....
Quote from: Herb Schaltegger on 09/25/2016 10:31 pmQuote from: Robotbeat on 09/25/2016 10:15 pmQuote from: CuddlyRocket on 09/25/2016 09:07 pmQuote from: guckyfan on 09/25/2016 05:06 pmEven extracting the water from the atmosphere is not helpful in that respect as it cannot yield the amounts of water for fuel ISRU and supplying a base later. ... Only producing the water in the same way that will be needed for ISRU later is going to give really useful data. Everything else is more PR.Water has other uses than ISRU. Granted, any process to produce water in the quantities needed for ISRU will likely also produce the water for other purposes. But, I'd want a back-up water supply using an entirely separate process, and there may be a need to produce water in small quantities using compact equipment; perhaps in satellite habitats or on long-range rovers?In general, I'm suspicious of the idea that there is one 'best' way to do anything. Especially in a new environment, diversity is a strength and safeguard.First of all, I'd challenge the claim that air reclamation of water can't yield enough water. It certainly can! But the same technique could be used for extracting water from ice or regolith, it's just that you would heat the regolith/ice first in a sealed enclosure and your yield would be MUCH higher. But the techniques are basically the same. Or could be, depending on exactly what approach you take.And again ... how do you integrate this stuff into a Red Dragon mission and how do you justify the proportionally gigantic share of the power, mass and data budget to justify it? That's the question no one has an answer for. Continuing to avoid it doesn't make it go away.....How does MOXIE answer those SAME EXACT QUESTIONS?THAT is the thing that /you/ keep avoiding. NASA is basically doing the same thing on the 2020 rover, except CO2-based instead of water-based.So if doing a subscale ISRU demo is so dumb for SpaceX (whose architecture depends so deeply on ISRU), why is NASA doing MOXIE??Until you answer that question, I see no reason to try to answer your kind of silly questions (silly because the answers are obvious...).
Quote from: Robotbeat on 09/26/2016 12:47 amQuote from: Herb Schaltegger on 09/25/2016 10:31 pmQuote from: Robotbeat on 09/25/2016 10:15 pmQuote from: CuddlyRocket on 09/25/2016 09:07 pmQuote from: guckyfan on 09/25/2016 05:06 pmEven extracting the water from the atmosphere is not helpful in that respect as it cannot yield the amounts of water for fuel ISRU and supplying a base later. ... Only producing the water in the same way that will be needed for ISRU later is going to give really useful data. Everything else is more PR.Water has other uses than ISRU. Granted, any process to produce water in the quantities needed for ISRU will likely also produce the water for other purposes. But, I'd want a back-up water supply using an entirely separate process, and there may be a need to produce water in small quantities using compact equipment; perhaps in satellite habitats or on long-range rovers?In general, I'm suspicious of the idea that there is one 'best' way to do anything. Especially in a new environment, diversity is a strength and safeguard.First of all, I'd challenge the claim that air reclamation of water can't yield enough water. It certainly can! But the same technique could be used for extracting water from ice or regolith, it's just that you would heat the regolith/ice first in a sealed enclosure and your yield would be MUCH higher. But the techniques are basically the same. Or could be, depending on exactly what approach you take.And again ... how do you integrate this stuff into a Red Dragon mission and how do you justify the proportionally gigantic share of the power, mass and data budget to justify it? That's the question no one has an answer for. Continuing to avoid it doesn't make it go away.....How does MOXIE answer those SAME EXACT QUESTIONS?THAT is the thing that /you/ keep avoiding. NASA is basically doing the same thing on the 2020 rover, except CO2-based instead of water-based.So if doing a subscale ISRU demo is so dumb for SpaceX (whose architecture depends so deeply on ISRU), why is NASA doing MOXIE??Until you answer that question, I see no reason to try to answer your kind of silly questions (silly because the answers are obvious...).We're not talking about MOXIE. This is what is known as a "strawman argument." You can do better than this, Chris. The topic at hand is Red Dragon. Until you grasp that, I'm out.
Quote from: CuddlyRocket on 09/25/2016 09:07 pmWater has other uses than ISRU. Not sure what you mean. Everything using local water from any source is ISRU. You are not thinking of bringing water from earth, correct?
Quote from: CuddlyRocket on 09/25/2016 09:07 pmBut, I'd want a back-up water supply using an entirely separate process...I understand there is a need for redundancy. Still there is only one reasonable source for tens of thousands of tons of water for the main settlement. That's glacial water. For redundancy different systems for extracting it can be used.
But, I'd want a back-up water supply using an entirely separate process...
Is it a stunt to acquire samples in a mining flow (arm, bucket loader/trencher, coring drill with slurry pump, ...), and assay yields and impurities? Even if the scale of the operation is centimeters not meters?Is it a stunt to precipitate atmospheric components to get mass yields for lightbulb wattage "production plant", where you can possibly validate reaction/force product with an actual static test thruster? And quite possibly redo the experiment a few hundred times, being able to visually inspect the throat for combustion products/erosion?At which point do we move from "stunt" to "engineering test article"?