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#26 2017-12-22 18:48:14

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
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Re: Falcon Heavy Assembly Underway

Oldfart1939 wrote:

Russian...not sure which...either MMH or UDMH

UDMH

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#27 2017-12-23 05:07:05

kbd512
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Re: Falcon Heavy Assembly Underway

Oldfart1939,

If we can make AF-M315E on Mars, then we have a propellant that has fantastic density impulse without fantastic power requirements for storage.  Both production and storage of cryogenic fuels is an inherently energy intensive process.  LOX can be manufactured from the Martian atmosphere, but LH2 and LCH4 both require considerable quantities of water.  Maybe my math is off, but I think around 9kg of H2O is required to obtain 1kg of H2, maybe more.  My understanding is that AF-M315E is some form of aqueous HAN, but could it be shipped without water and hydrated with water from the Martian atmosphere (WAVAR) or regolith?  What precursors could we send to combine with CO2 and/or N2 from the atmosphere, along with some chemistry magic, to obtain AF-M315E?

64% of HAN is Oxygen
28% of HAN is Nitrogen
4% of HAN is Hydrogen

The Martian atmosphere is 1.89% Nitrogen and 95.97% Oxygen.  Curiosity has discovered nitrates in the regolith of Mars at multiple sites, released as nitric oxide from heated sediment samples.  Maybe it's time to see what we can dig out of the ground there.  Usable quantities of water would be nice, too.  There are plenty of Sulfur deposits on Mars.

You're the expert on this stuff, so what does that buy us?

If we just sent nitric acid, could we still make AF-M315E or Hydrazine?

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#28 2017-12-23 16:16:13

Oldfart1939
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Registered: 2016-11-26
Posts: 1,889

Re: Falcon Heavy Assembly Underway

kbd512-

I need to research the AF-M315E, but I'm a KISS principle kind of guy. I happen to like the idea of manufacturing UDMH from in-situ materials. That is manufactured from Chloramine and dimethyl amine. I haven't really looked into this other that superficially on Wikipedia, but there is a finite possibility that we can obtain enough Nitrogen from the Martian atmosphere to make these two intermediates. I like UDMH because it's a liquid at most reasonable temperatures and does not require pressure vessels or cryogenic handling. The most straightforward component to manufacture at this stage is the LOX using the moxie technology, and that of itself is a huge contribution to getting any rocket back to Earth from Mars. The key component we need from Mars is water, good old H2O. We find water deposits that are readily available, we're in business. That's our primary source of Hydrogen.

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#29 2017-12-24 11:17:49

SpaceNut
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Re: Falcon Heavy Assembly Underway

If we had to bring along a seed that would be Ammonia compound made of Nitogen and Hydrogen or another formula NH3 Ammonium which is the ionized form of Ammonia chemical symbol NH4. electrolysis will give the needed components for making the storeable and it gives a much needed buffer gas for the habitat as well as for gardening....

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#30 2017-12-24 12:01:57

RobertDyck
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Re: Falcon Heavy Assembly Underway

Ammonia is NH3. Ammonium is the ionized form, NH4+

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#31 2017-12-24 13:22:51

Oldfart1939
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Re: Falcon Heavy Assembly Underway

In the long term, I really don't like cryogenic propellants due to constant boil-off. I would be much happier with an architecture based on N2O4 and H2NNC2H6. NO ignition worries; no boil-off problems. Yeah, they are toxic. So what? The Titan rockets all used hypergolic and storable fuels/oxidizers. The Russian Proton rocket is entirely UDMH/N2O4.

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#32 2017-12-24 14:18:18

RobertDyck
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Re: Falcon Heavy Assembly Underway

Spacesuits are designed to handle -156°C to +120°C (±250°F). Deep space has a temperature of 2.7°K = -270.45°C. So what temperature can you maintain by simply providing shade and insulation? LOX at 1 atmosphere boils at -182.96°C, shuttle operated the LOX tank of it's external tank at 22 psig. That's Pounds per Square Inch, Gauge. Or pressure relative to ambient. Earth's air pressure at sea level is 14.69595 psi, so 22 psig at KSC is 36.7 psia. At that absolute pressure, LOX boils -169°C. In the vacuum of space that would be 36.7 psig, so would require a slightly stronger tank.

Do you want me to do that with LCH4? Liquid methane at 1 atmosphere boils at -161.48°C. At 36.7 psia, LCH4 boils at -149°C. Do you want lower pressure? At 22 psia in space, that's 22 psig, so the same stress on the tank as Shuttle's ET LOX tank. At that pressure, LCH4 boils at -156.35°C.

The point is LOX and LCH4 are soft cryogens. We should be able to manage them without boil-off in space.

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#33 2017-12-24 14:51:07

Oldfart1939
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Re: Falcon Heavy Assembly Underway

Robert-

I'm more concerned with the necessary infrastructure to store them in sufficient quantities on the planetary surface without need to construct huge pressurized and insulated vessels. You know I'm aware of them being soft cryogens, and CH4 is only semi cryogenic. None of this is going to be easy, though. Regardless of fuel/oxidizer choice.

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#34 2017-12-24 15:44:46

kbd512
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Re: Falcon Heavy Assembly Underway

On Earth, rockets constantly vent cryogenic propellants from their propellant tanks to prevent those tanks from bursting.  Now we have a mission requirement to store those propellants in the same type of tanks aboard a similar vehicle for up to two years.  How many rockets have ever had their propellant tanks filled with LOX for two years?  What type of thermal cycling will that entail?  Will a composite or even an aluminum alloy tank stand up to that sort of stress when it's designed to be thinner than a scaled up soda can?  Someone needs to test this by slowly filling LOX/LCH4 into test article tanks in Antarctica for two years to determine what's necessary for a vehicle equipped with similar tanks to safely contain its LOX/LCH4 on the surface of Mars for at least two years.  Nobody has addressed dust contamination from the Martian atmosphere or the need to keep the cryocooler and pump operational for two years in that environment, either.  LOX reacts with just about everything, so what sort of stuff in the Martian atmosphere needs to be filtered out?  If we just have to live with some iron oxide in the tanks, how will that affect the turbopumps and injectors?  Has someone tested this?

For any of this to work, even if those problems I already mentioned are easily solvable, we have to land a tall vehicle with a short landing gear base on or near a glacier and it can't tip over when it lands or as it's loaded with propellants.  We've been landing reusable rockets on steel ships and steel reinforced concrete here on Earth using crush tubes inside the landing gear.  The crush tubes were intended to support the weight of an empty rocket, not one loaded with propellants.  The landing area itself must now support a vehicle loaded with thousands of tons of propellants.  If the ground shifts substantially, then the vehicle will tip over.  That means we have to find a solid landing area on Mars that's near a glacier.  Nobody has explained how they intend to assure that that happens.  If any of this doesn't work with a remotely operated lander, then hundreds of millions of dollars will be lost.  If any humans happen to be aboard, then they'll be permanent residents if they aren't killed when the rocket tips over, the tanks crack, or the propellant plant pumps seize.

We don't allow humans to be anywhere near a rocket when propellants are being loaded here on Earth, so why would we do it on a planet tens of millions of miles from home?  That means they need a separate habitation module for use on Mars while the propellant depot and rocket landing area are in use.  The rocket itself, power source, and propellant plants require exclusion zones.  Basically, these Martian pioneers need their own separate surface habitation that they can move away from the rocket.

ISPP is not a hand wave that solves any of the problems I mentioned above.  Someone needs to test all of that stuff.  If I was working at NASA, I wouldn't let anyone bet other peoples' lives on this concept until it's tested.  That means someone needs to get to work testing this.  That's where Falcon Heavy comes in.

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#35 2017-12-24 16:14:19

RobertDyck
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Re: Falcon Heavy Assembly Underway

Yup, propellant tanks on Mars will be huge pressurized and insulated vessels. And since Mars surface temperature is a lot warmer, for example Mars Pathfinder found temperatures over 3 sols varied from -8°C to -77°C. Curiosity has reported Mars weather as of December 20, the high was -23°C, low -80°C. Ground temperature was -7°C to -85°C. So yea, a Mars surface depot will require active refrigeration.

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#36 2017-12-24 16:51:28

Oldfart1939
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Registered: 2016-11-26
Posts: 1,889

Re: Falcon Heavy Assembly Underway

The other consideration of using cryogenic and soft cryogens is the initial energy expenditure in the liquefaction process. We've had all sorts of discussion regarding the necessary energy required, and outright arguments as to the source of that power. The power required to liquefy and store hundreds of tons of LOX, lCH4 is itself an enormous consideration.

I'm simply utilizing my chemical process experience here--not trying to dissuade anyone from anything. But we need to consider the total "system," before launching anything remotely human rated with people on board. The overall size of the rocket will shrink if non cryogenic propellant combinations are used. Even the original Mars direct proposal carried along a consumable supply of H2 for conversion to CH4 and water, which would then be electrolyzed to more H2 and O2.

The total "system" is more than the Sabatier reaction hardware and Moxie units. It includes the necessary equipment for liquefaction of the gaseous products, and then their storage. Which should be heavy tankage and insulation. If it's going to take 150+ days to manufacture all these components in the propellant system, there will be boil-off losses and some leakage. It seems that all the aerospace engineers are blind to the weight of chemical process equipment needed.

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#37 2017-12-24 17:36:17

RobertDyck
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From: Winnipeg, Canada
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Re: Falcon Heavy Assembly Underway

kbd512 wrote:

we have to find a solid landing area on Mars that's near a glacier.  Nobody has explained how they intend to assure that that happens.

In 2005, president of the Canadian Space Agency proposed sending a rover to Mars the size of Spirit or Opportunity. It would include a core drill with 10 segments, each 1 metre long. A prototype drill was demonstrated at that symposium. Unfortunately Parliament didn't approve funding. I propose sending a rover like this to a potential site for a human mission, verify presence of ice, and ground conditions.

kbd512 wrote:

Basically, these Martian pioneers need their own separate surface habitation that they can move away from the rocket.

Mars Direct landed the rocket (ERV) and habitat separately. They would land within walking distance, but far enough apart that rocks through up by exhaust from landing rockets would not hit the other vehicle.

kbd512 wrote:

That means someone needs to get to work testing this.  That's where Falcon Heavy comes in.

No duh.

Spirit and Opportunity were launched on Delta II 7925-9.5 rockets. Delta 7000 variants could lift 2,700–6,100 kg to LEO. Total mass to TMI was 1,063 kg. Falcon 9 is capable of lifting 22,800 kg to LEO, or 4,020 kg to TMI. So Falcon 9 is more than enough to send the "scout" rover I just mentioned. I wonder what the throw mass to TMI is when the first stage is reused?

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#38 2017-12-24 18:03:08

RobertDyck
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From: Winnipeg, Canada
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Posts: 6,120
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Re: Falcon Heavy Assembly Underway

Oldfart1939 wrote:

I'm simply utilizing my chemical process experience here--not trying to dissuade anyone from anything. But we need to consider the total "system,"

What does it take to make H2NNC2H6? That's a large molecule, and I have no clue. However, I have posted a proposal to harvest nitrogen gas from Mars atmosphere. It's much more energy intensive than harvesting CO2.

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#39 2017-12-24 19:34:16

Oldfart1939
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Registered: 2016-11-26
Posts: 1,889

Re: Falcon Heavy Assembly Underway

By the way, this is my 1,000th post on this forum.

Robert-
The chemistry is pretty straightforward.

H2N-Cl    + HN(CH3)2   -----------------> UDMH

There was a comment posted elsewhere in this thread about the possibility of nitrates being found in some areas.

In a real world scenario, this could become the first industry on Mars: the chemical process industry!

Chloramine from ammonia, and simply dimethylamine. Both are simple molecules which can be stored. The reaction is definitely exothermic, but controllable. This is the basis of the Raschig Hydrazine synthesis.

Last edited by Oldfart1939 (2017-12-24 19:52:05)

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#40 2017-12-24 19:59:34

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,657

Re: Falcon Heavy Assembly Underway

https://www.webqc.org/chemicaltools.php

http://www.eng.ox.ac.uk/cryogenics/rese … plications

http://uspas.fnal.gov/materials/10MIT/Lecture_5.1.pdf

https://ntrs.nasa.gov/archive/nasa/casi … 016225.pdf

Cryogenic Technology:  Ongoing Developments for the Next Decade
https://ntrs.nasa.gov/archive/nasa/casi … 074263.pdf

Cryogenic Characterization of the Planck Sorption Cooler System Flight Model
https://arxiv.org/ftp/arxiv/papers/1001/1001.4628.pdf

Active Versus Standby Redundancy for Improved Cryocooler Reliability in Space
https://www2.jpl.nasa.gov/adv_tech/cool … 20Redn.pdf

https://tfaws.nasa.gov/TFAWS12/Active_T … tracts.pdf

Cryogenic Propellant Storage & Transfer (CPST) Technology Demonstration Mission (TDM) CPST  Technology Maturation Activity
Status December 14, 2012

https://www.nasa.gov/pdf/743213main_CPS … ration.pdf

Air Force Research Laboratory Space Cryogenic Technology Research Initiatives
http://cryocooler.org/proceedings/paper … rs/002.pdf

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#41 2017-12-25 01:17:38

kbd512
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Re: Falcon Heavy Assembly Underway

SpaceNut,

Thanks for the links.  There's some stuff there that I haven't read before.

Rob,

Falcon Heavy could land a demonstrator mission of the type you propose at a scale that provides a good indicator of what the results would be on future missions that require ISPP.  That's what I was trying to get at.  I want NASA to use this rocket to determine what we need for LOX/LCH4, LOX/LH2, LOX/UDMH, or whatever works best on Mars.

Regarding the requirement for separate activity areas on Mars, I wanted to land the astronauts in a mobile habitat or in tracked rovers that are built like armored personnel carriers so it doesn't matter if something hits the rover.  Falcon Heavy could deliver this sort of stuff to the surface of Mars using existing chemical propulsion technologies.

The idea of landing everything in a single large and expensive cargo ship that may or may not be able to come back if anything goes wrong seems counter-productive to me.  There are too many potential failures that could result in the loss of the ship.  We're just not to the point where science and technology can make this a routine operation.

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#42 2017-12-25 01:38:46

Oldfart1939
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Registered: 2016-11-26
Posts: 1,889

Re: Falcon Heavy Assembly Underway

kbd512 wrote:

SpaceNut,
The idea of landing everything in a single large and expensive cargo ship that may or may not be able to come back if anything goes wrong seems counter-productive to me.  There are too many potential failures that could result in the loss of the ship.  We're just not to the point where science and technology can make this a routine operation.

I agree wholeheartedly with your assessment of the risk versus rewards. My mission architecture is more modest than that proposed by Elon, but...it's his money at risk. I would prefer to see a pioneer mission using the Falcon X sized vehicle with from 7-12 astronauts for an exploration/resource utilization landing and stay. It would be a proof of concept. Gotta' go there once or twice before putting too many eggs in that giant basket.

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#43 2017-12-25 22:33:10

SpaceNut
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From: New Hampshire
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Posts: 19,657

Re: Falcon Heavy Assembly Underway

Well the critical leg of the mars mission regarding quantity of personnel on its surface for the duration is volume and mass requirements of what can be landed and thats just about 2 mt at this point of a 25m cubed capsule, with hope that retro propulsion use could get higher into the 10 to 20 mt range. Sizing the crew for the above demensions means going with less and digging in via preloading a site with the best guestimates of water in some form or another.

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#44 2017-12-25 22:51:16

kbd512
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Re: Falcon Heavy Assembly Underway

Oldfart1939,

I see Falcon Heavy as a mission enabler, much like that air launch microwave propulsion concept I advocated testing.  The cost to deliver cargo to ISS with either technology is low enough that we can affordably deliver hundreds of tons per year with current NASA budgets.  The giant rockets and spaceships concepts are fun to imagine, but STS was so obscenely costly for the capability it provided that it wasn't a mission enabler.  For all intents and purposes, BFS is a scaled-up orbiter that can land on other planets.  Engineering reality says that BFS will be every bit as unaffordable as STS was.  BFS is a different concept than STS to be sure, but we've already tried this giant reusable spaceship thing before and reality never merged with the promise of the concept.  Whereas BFR may have some future utility, SLS is just an inexcusable waste of tax payer money.  NASA is already paying SpaceX to deliver cargo and astronauts to ISS and they're pretty good at it, so ISS is the natural point of departure as long as we intend to pay for that station indefinitely.  At this point, ISS costs too much to throw away.

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#45 2017-12-25 23:38:06

Oldfart1939
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Registered: 2016-11-26
Posts: 1,889

Re: Falcon Heavy Assembly Underway

kbd512-
You won't get any argument or complaints from me if the SLS is cancelled. My comments have been trying to figure a way of making economics and present day engineering capability coincide. I'm a strong admirer of Elon Musk and his visions of the future, but I'm just worried that by skipping the Red Dragon experiments and going for the gusto with BFR, he may be setting himself up with "a rocket too far." The reality of landing such an enormous vehicle on small landing legs strikes me as highly risky--especially if we haven't landed something smaller and done the in situ soils research. We need at least 2 smaller precursor/pioneering missions before gambling all on the BFR.

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#46 2017-12-25 23:52:26

Oldfart1939
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Registered: 2016-11-26
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Re: Falcon Heavy Assembly Underway

Oldfart1939 wrote:

kbd512-
You won't get any argument or complaints from me if the SLS is cancelled. My comments have been trying to figure a way of making economics and present day engineering capability coincide. I'm a strong admirer of Elon Musk and his visions of the future, but I'm just worried that by skipping the Red Dragon experiments and going for the gusto with BFR, he may be setting himself up with "a rocket too far." The reality of landing such an enormous vehicle on small landing legs strikes me as highly risky--especially if we haven't landed something smaller and done the in situ soils research. We need at least 2 smaller precursor/pioneering missions before gambling all on the BFR.

Changing gears a bit--going back to my industrial chemistry experience and the concept of scale-ups. Using the Falcon Heavy, there's no doubt in my mind that SpaceX would succeed in landing 2-4 mt on the mars surface. To make scale-up a useful but still realistic process, in my industry anything less than a 3X scale was considered an absolute waste of effort, and more realistic--a 5x to 8X scale, and pushing things a bit--10X scale up was considered useful and desirable. So something on the order of landing 16 mt is reasonable for the next step. This is in the ballpark of the New Glenn/Falcon X concept capacity.

Any mission should include 3 such spacecraft; in addition to 2 prepositioned with supplies for the crew(s) for 1000 days. This allows for any monster disasters in meeting the mission requirements during a Hohmann transfer window.   

So in a way, I'm reinforcing kbd512's comments about not betting too much of one Big F*****g Rocket.

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#47 2017-12-26 06:24:19

kbd512
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Re: Falcon Heavy Assembly Underway

Oldfart1939,

I get what you're saying.  I, too, believe that the backups should have backups.  Dr. Zubrin was correct on that point.  There are too many things that can fail in the span of three years or more to not plan the mission that way.  The life support equipment aboard ISS doesn't run for two years between maintenance cycles.  That's pretty basic stuff.  The reusable rockets, aluminum habitat modules, solar panels, Lithium-ion batteries, and thermal control systems are 100% good to go.  That's about it.  Everything else needs MAJOR work.  The life support systems, radiation protection systems, computer and communication systems, orbital transfer stages, and landers that barely exist on paper all require extensive development work.  After that's done, someone has to integrate and test all this stuff.  Ten million miles from Earth is not the place to discover that someone used Torx bolts on the life support systems when flat heads were the only driver bits supplied to the astronauts.

Everyone here seems to believe that SpaceX has already solved all of these fundamental problems and more without a scintilla of evidence.  I wish that was true, but doubt that it is.  I also doubt that Mr. Musk has anyone on staff who has ever seen, much less designed / built / tested / flown, a closed loop life support system.  This mission won't happen without stuff like that.  Publicity stunts aside, Mr. Musk is about six years late delivering a rocket that's roughly equivalent in configuration to a Delta IV Heavy.  That doesn't give me much confidence that his launch date estimates regarding when he could possibly land something on Mars are even close to being accurate.  At this point, I still have more confidence in his ability to get things done than NASA.  When he says he's going to do something, he actually does it, just not when he thinks he's going to get it done.

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#48 2017-12-26 18:11:42

Oldfart1939
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Registered: 2016-11-26
Posts: 1,889

Re: Falcon Heavy Assembly Underway

kbd512-

More than backups--redundancy! We send spares of EVERYTHING! That includes return transportation systems, construction supplies and apparatus, but most of all--FOOD, AIR, WATER, SHELTER. We need to have plenty of equipment, water, food, and construction supplies prepositioned--in duplicate. I'm strongly in favor of an approach which emulates "belts and breeches," if we want to hold our pants up.
Point is--if we don't need it, we are building additional reserves for follow on missions. Making certain we DO NOT FAIL!

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#49 2017-12-26 18:45:38

louis
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From: UK
Registered: 2008-03-24
Posts: 5,868

Re: Falcon Heavy Assembly Underway

With Space X's plan -  two cargo BFSs landing 300 tonnes two years before humans arrive - you can build in a lot of redundancy. Likewise with the human flight itself.  But I don't think there's any way around the risk of rocket or flight control failure itself...that is the risk the crew have to live with I think. But actually space is a very benign environment so we can be positive about this I think.

Oldfart1939 wrote:

kbd512-

More than backups--redundancy! We send spares of EVERYTHING! That includes return transportation systems, construction supplies and apparatus, but most of all--FOOD, AIR, WATER, SHELTER. We need to have plenty of equipment, water, food, and construction supplies prepositioned--in duplicate. I'm strongly in favor of an approach which emulates "belts and breeches," if we want to hold our pants up.
Point is--if we don't need it, we are building additional reserves for follow on missions. Making certain we DO NOT FAIL!


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#50 2017-12-26 22:50:36

SpaceNut
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From: New Hampshire
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Posts: 19,657

Re: Falcon Heavy Assembly Underway

Loius you have missed the point that its not just the cargo its the massive weight of the entire rocket that lands as its not only untested on a mars surface but we can not even take off once we have landed the beast until we have refueling capability on mars. Any crew will be landing in a simular rocket with it being outfitted for the crew. Space X BFR if tried here on an unprepared landing as a test of whether it will or will not work without knowing if it will, then how can we do so on mars.....

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