New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: We've recently made changes to our user database and have removed inactive and spam users. If you can not login, please re-register.

#51 2017-08-31 16:58:50

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

Re: Space X - getting ready for Mars.

I accept there are lots of unknowns, but exploration cannot be risk free.

I think solar flare protection can be provided whether or not your craft has artificial G (AG). So that's an irrelevance essentially. Presumably in a traditional craft, you would simply build an internal solar flare shield, probably using water storage tanks.

Whilst an AG craft potentially reduces the health risks of zero G (we presume so, though we don't yet know - since artificial G has no presumed gravity waves/particles as does real gravity) it also creates a new risk - of catastrophic failure that might somehow send the craft off course.

It would require years of development and testing.  With my suggested approach, you could (assuming let's say we are running with Space X technology which should be available within the next 2-5 years) be running Mars simulations through Earth-Lunar expeditions over 2-4 years with real humans on real craft in real zero and minimal G and seeing how they perform.  You would build up the lunar surface time gradually - maybe starting with 3 months, then 6 months, and then a year or more. The crew would wear weighted 1 G simulation suits on the Moon (or maybe that could be raised to 1.2).  If it proves the case that people cannot cope with the Mars simulation and have to be brought home early, you know you have a problem on your hands, but personally I think  the problems can be overcome.



Oldfart1939 wrote:

Louis-

What we don't really understand is how the human--or any animal's---physiology even detects the absence of gravity. Is there a "gravity receptor," or are the effects individually responses to the absence of the stimulus? The issue of making the Mars journey less stressful is important, and minimizing the issue intellectually doesn't help. One of the architectures I conceived earlier was in many respects almost identical to that which GW has suggested. The first question to be answered is whether the "baton-like" structure should be sent tumbling end over end, or with the axis of flight be perpendicular to the axis of module rotation. It would seem reasonable for the end over end tumbling to have fewer complications w/r to midcourse corrections. The spacecraft design in The Martian seemed to show the axis of bicycle wheel rotation being the line-of-flight, however.

Regarding protection from Solar Flare Radiation was initially addressed by Zubrin by using the food and water supply. I would consider enhancement by incorporation of significant HDLPE in the internal structure of the spacecraft. HDLPE = High Density Linear Poly Ethylene, which is a hydrogen-rich polymer of adequate physical properties for structure. My thought was having individual "Bunk cocoons" for the crew, with all the structure being composed of the HDLPE with maybe a water mattress included. Stack several bunks atop one another all with water mattresses would undoubtedly serve to attenuate the solar flare radiation exposure. Radiation can certainly never be completely eliminated, but CAN be adequately attenuated.


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

Offline

#52 2017-08-31 20:33:27

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,686

Re: Space X - getting ready for Mars.

I tried to post this yesterday but I guess my network failed to transmit it.

Weightlessness affects health of cosmonauts at molecular level

A team of scientists from Russia and Canada has analyzed the effect of space conditions on the protein composition in blood samples of 18 Russian cosmonauts. The results indicated many significant changes in the human body caused by space flight.

These changes are intended to help the body adapt and take place in all the major types of human cells, tissues, and organs.

It is widely known that space conditions influence metabolism, thermoregulation, heart biorhythms, muscle tonus, the respiration system and other physiological aspects of the human body function. However, the molecular mechanisms which drive the physiological changes caused by space flights remain unknown.

Proteins are key players in the adaptive processes in an organism, so the scientists decided to focus on them. To gain a deeper understanding of the changes in human physiology during space travel, the research team quantified concentrations of 125 proteins in the blood plasma of 18 Russian cosmonauts who had been on long-duration missions to the International Space Station.

The blood was initially taken from them 30 days prior to their flights, and again immediately after their return to Earth and finally seven days after that. This timing was chosen as it helped the scientists to identify trends in protein concentration changes and see how fast the protein concentrations returned to their normal levels prior to the flight.

Protein concentrations were measured using a mass spectrometer. This technology makes it possible to identify a particular molecule and perform a quantitative analysis of a mixture of substances (count the exact number of molecules).

As a result of the study, the scientists found proteins whose concentrations remained unchanged, as well as those whose concentrations did change, but recovered rapidly to their pre-flight levels and those whose levels recovered very slowly after the cosmonaut's return to Earth.

"For the research, we took a set of proteins - non-infectious diseases biomarkers. The results showed that in weightlessness, the immune system acts like it does when the body is infected because the human body doesn't know what to do and tries to turn on all possible defense systems.

For this study, we began by using quantitative proteomics to study the cosmonauts' blood indicators, so we detected not only the presence of a protein but its amount as well. We plan to use a targeted approach in the future to detect more specific proteins responsible for the human response to space conditions.

Offline

#53 2017-09-01 16:01:03

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

Re: Space X - getting ready for Mars.

From the NASA Website - there is surprisingly little alarmism:

Gravity Fields. There are three gravity fields you would experience on a Mars mission.  On the six-month trek between the planets, you would be weightless. On the surface of Mars, you would live and work in approximately one-third of Earth’s gravity, and when you return home you will have to readapt to the gravity we take for granted.  Transitioning from one gravity field to another is trickier than it sounds.  It affects your spatial orientation, head-eye and hand-eye coordination, balance, locomotion, and you’re likely to experience motion sickness.  If you have to land a spacecraft on Mars, it could be a pretty dangerous situation.  NASA has learned that without gravity working on your body, your bones lose minerals, with density dropping at over 1% per month.  By comparison, the rate of bone loss for elderly men and women on Earth is from 1% to 1.5% per year.  Even after returning to Earth, your bone loss might not be corrected by rehabilitation, so you could be at greater risk of osteoporosis-related fractures later in life.  If you don’t exercise and eat properly, you will lose muscle strength, endurance, and experience cardiovascular deconditioning since it does not take effort to float through space.  The fluids in your body will shift upwards to your head, which could put pressure on your eyes causing vision problems.  You’re apt to develop kidney stones due to dehydration and increased excretion of calcium from your bones.  Medications react differently in your body in space.  Nutrition, including eating enough, becomes important, otherwise you could compromise your health since nutrients are required for the function of every cell and system in your body.
Gravity Icon

The Key:  By analyzing how your body changes in weightlessness and after returning to Earth’s gravity, protection against these changes for a Mars mission can be developed.  Functional task testing is in place to help detect and minimize the effects of space on your balance and performance.  Fine motor skills testing is done to detect any changes in your ability to interact with your computer-based devices. Distribution of the fluids in your body will be closely monitored, to help evaluate any connection to changes in your vision.  Compression cuffs worn on your thighs will help keep the blood in your lower extremities to counteract those vision changes.  Your back pain would be monitored by obtaining spinal ultrasounds.  You will perform periodic fitness self-evaluations that help researchers better understand the decline in cardiovascular function that can occur during spaceflight. Some medicines, like potassium citrate (K-Cit), may help you combat the physiological change that could increase the risk for developing kidney stones.  Bisphosphonates drugs have shown to be effective in preventing bone loss.  NASA has also designed an efficient way to collect and measure how much urine you produce in space, which is essential to human research since it reveals key information about your health.  You will get proper nutrition, including vitamin D supplements since you can’t walk outside under the sun.  And last, good old regular exercise has been shown to keep your heart healthy, your bones and muscles strong, your mind alert, your outlook more positive, and may even help with your balance and coordination. 


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

Offline

#54 2017-09-02 09:06:17

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,686

Re: Space X - getting ready for Mars.

Peggy Whitson clocks in 665 days in space

While this was not nonstop its going give valueable data to go against the male counterparts.

AP_17103654020183_12x5_992.jpg

Astronaut Peggy Whitson is approaching an astronomical landmark: 665 days in orbit over three missions, giving her the record for the most time in space of any American.

Whitson will complete her current mission -- having spent a year in space -- when she lands Saturday in Kazakhstan, at 9:22 p.m. ET. She has circumnavigated 122 million miles of the globe -- the equivalent of traveling to Mars and back nearly twice.

Over her career, she has made 10 spacewalks totaling 60 hours and 21 minutes -- ranking third on the all-time list for spacewalks.

Offline

#55 2017-09-02 11:52:55

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

Re: Space X - getting ready for Mars.

Well, she looks pretty healthy, doesn't she?

This sort of monitoring can be given even more of a realistic edge by conducting "dry runs" to the moon (doing figure eights around the Earth and Moon for 200 days) before landing on the Moon and engaging in Mars style activity and then doing another 200 days of "return". 

SpaceNut wrote:

Peggy Whitson clocks in 665 days in space

While this was not nonstop its going give valueable data to go against the male counterparts.

http://a.abcnews.com/images/US/AP_17103 … x5_992.jpg

Astronaut Peggy Whitson is approaching an astronomical landmark: 665 days in orbit over three missions, giving her the record for the most time in space of any American.

Whitson will complete her current mission -- having spent a year in space -- when she lands Saturday in Kazakhstan, at 9:22 p.m. ET. She has circumnavigated 122 million miles of the globe -- the equivalent of traveling to Mars and back nearly twice.

Over her career, she has made 10 spacewalks totaling 60 hours and 21 minutes -- ranking third on the all-time list for spacewalks.

Last edited by louis (2017-09-02 13:15:47)


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

Offline

#56 2017-09-02 16:38:30

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,686

Re: Space X - getting ready for Mars.

To do the figure 8 around the moon loops require the deep space habitat and at a minimal ion drive to make use of with occasion full engine use for course corrections. This is on Nasa's plate but its a dish they are not moving on very fast as its not required for sls or moon missions.

So what makes up the deep space habitat is the issue that Nasa seems to be still working out the details on.
IIRC we have a topic for this...
.
http://newmars.com/forums/viewtopic.php?id=7366

Offline

#57 2017-09-02 17:01:53

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,077
Website

Re: Space X - getting ready for Mars.

The NASA stuff Louis posted in post 53 just above has two paragraphs.  The first pretty much confirms everything I said about microgravity diseases with two exceptions:  (1) they include kidney stone and drug action effects that I didn’t already know about,  and (2) they did not include the immune system damage effects that I did already know about. 

The second paragraph takes up how they expect to mitigate these risks without resort to artificial gravity.  What they say is true as far as it goes,  but they don’t say everything!  The experience we have  is return to Earth at no more than the 4 gees our folks see now,  coming home from ISS after 6 months to a year.  We have NO experience to show that 4 gees is survivable with microgravity exposure longer than a about a year.  14 months if you include the one (and only) Russian cosmonaut up there that long. 

NASA’s whole thesis is that 13 months at Mars at 0.38 gee is therapeutic enough to reverse the effects of 6-8 months weightless going to Mars.  It’s a thesis,  not a proven fact.

Implied is that it is therapeutic enough to help fortify the crew to survive 6-8 months more weightlessness exposure,  coming home.  That’s another unproven thesis.

If the spacecraft is recovered in LEO,  and the crew comes home from LEO,  this scenario might actually be true.  But we have precisely ZERO experience at partial gee to back this unsupported thesis up!

But for any free-return mission design,  or any emergency “bailout” return scenario,  this is NOT true!  Such scenarios are free-return entries at low angle into the atmosphere at around 17 km/s entry speed,  and that’s closer to 12-15 gee (maybe even higher) at peak entry deceleration,  in a pulse around 2-3 minutes long. 

We have to-date precisely ZERO evidence that this scenario is survivable,  and every reason to believe it is NOT survivable,  due to the cardiovascular weakening already observed after only 6 months exposure to weightlessness.  Exercise mitigates it,  but DOES NOT REVERSE it!  So much for weighted suits on the moon or Mars.

NASA has two long-favored contractors,  Boeing and Lockheed-Martin,  agglomerated into an oligopoly from the plethora of contractors available in the 1950’s and 1960’s.  Neither of these favored oligopoly contractors has ever proposed anything but a weightless transit to and from Mars,  and cannot propose anything different,  without abandoning all their prior work.  Money-already-spent says they cannot abandon that earlier work in favor of something new and different.  How hard is THAT to understand?

This shows in the ridiculously-large rotating centrifuge module designs that have surfaced to answer this microgravity issue.  That is where the enormous rotating structures attached to non-rotating main ship structures come from.  These have entered popular fiction as the Earth ships of “Babylon-5”,  and the gigantic (but otherwise unexplained) vessel in “the Martian”.  We DO NOT need to do it that way!

What I showed was that this outcome is nothing but expensive gravy-train corporate welfare nonsense.

NASA has a preference for Boeing and Lockheed-Martin designs,  as evidenced by the 90-day report and some other recent egregious examples.  These reflect more a favored contractor bias,  than anything else.  It shows in the price tag,  too. 

That’s where the roughly half-a-trillion $ Mars mission price figure came from,  for nothing but a weightless-transit mission.  The mission re-worked for artificial gravity is supposedly even more costly. 

And yet,  we who have actually sized-out such missions already know that to be egregious bullshit.  As stupid as Congress has repeatedly demonstrated itself to be,  they at least nixed that price tag!

As for the development times necessary for artificial gravity,  it depends upon how you do it!  Cable-connected stuff has a very long development time (many years),  because we know almost nothing about the myriad ways that concept can go wrong,  and about how to prevent those outcomes.  Spinning this with some sort of bearing-and-seal to a non-spinning portion of the vehicle,  falls in exactly that same long development time / high expense /we have no experience category. 

Spinning one rigid item does not!  We have centuries of experience with this in all sorts of steam and internal combustion engines,  all sorts of windmills,  and all sorts of tire and wheel-balancing apparatuses since the dawn of automotive technology.  All we have to do,  is prove out some real spacecraft components while doing the confirmation experiments.  This is not at all the same as proving out the cable-connected stuff or the spin bearing stuff!  I’m sorry,  it’s just not! 

So,  Louis and I disagree on this issue. 

I think it is stupid to avoid incorporating spin gravity.  I also think it is stupid to do anything other than one single rigid spinning object. 

GW

Last edited by GW Johnson (2017-09-02 17:04:02)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

Offline

#58 2017-09-02 18:34:04

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

Re: Space X - getting ready for Mars.

I don't think we know whether the immune system changes are really a result of microgravity or rather a result of crew isolation (ie their immune system is not being stressed everyday through contact with pathogens).  I have never read anything to suggest that the immune system changes affect mission performance and astronauts seem to recover well post-mission.

It's true these are untested theses, but they can be tested through lunar Mars analogy missions conducted over varying periods until we get close to the 3 years of a Mars mission. Assuming the analogy missions work out, the risk for the Mars missions will be very low, and probably only to do with crew selection (you need to be absolutely sure you have people who perform well in zero G).

I'd agree with you that rigid spin is probably the way to go if you do go down that route, but it still has never been done over an extended period in space and therefore we don't know if we will encounter problems. One thing we do know though is that centrifugal (or  is it really centripetal? - I seem to remember reading someting on that) force is not the same as gravitational force so we don't know whether it will have the same effects on a human body over an extended period. I don't know what the record is on earth for being in a spinning machine but I suspect it's only days, not months.

GW Johnson wrote:

The NASA stuff Louis posted in post 53 just above has two paragraphs.  The first pretty much confirms everything I said about microgravity diseases with two exceptions:  (1) they include kidney stone and drug action effects that I didn’t already know about,  and (2) they did not include the immune system damage effects that I did already know about. 

The second paragraph takes up how they expect to mitigate these risks without resort to artificial gravity.  What they say is true as far as it goes,  but they don’t say everything!  The experience we have  is return to Earth at no more than the 4 gees our folks see now,  coming home from ISS after 6 months to a year.  We have NO experience to show that 4 gees is survivable with microgravity exposure longer than a about a year.  14 months if you include the one (and only) Russian cosmonaut up there that long. 


NASA’s whole thesis is that 13 months at Mars at 0.38 gee is therapeutic enough to reverse the effects of 6-8 months weightless going to Mars.  It’s a thesis,  not a proven fact.

Implied is that it is therapeutic enough to help fortify the crew to survive 6-8 months more weightlessness exposure,  coming home.  That’s another unproven thesis.

If the spacecraft is recovered in LEO,  and the crew comes home from LEO,  this scenario might actually be true.  But we have precisely ZERO experience at partial gee to back this unsupported thesis up!

But for any free-return mission design,  or any emergency “bailout” return scenario,  this is NOT true!  Such scenarios are free-return entries at low angle into the atmosphere at around 17 km/s entry speed,  and that’s closer to 12-15 gee (maybe even higher) at peak entry deceleration,  in a pulse around 2-3 minutes long. 

We have to-date precisely ZERO evidence that this scenario is survivable,  and every reason to believe it is NOT survivable,  due to the cardiovascular weakening already observed after only 6 months exposure to weightlessness.  Exercise mitigates it,  but DOES NOT REVERSE it!  So much for weighted suits on the moon or Mars.

NASA has two long-favored contractors,  Boeing and Lockheed-Martin,  agglomerated into an oligopoly from the plethora of contractors available in the 1950’s and 1960’s.  Neither of these favored oligopoly contractors has ever proposed anything but a weightless transit to and from Mars,  and cannot propose anything different,  without abandoning all their prior work.  Money-already-spent says they cannot abandon that earlier work in favor of something new and different.  How hard is THAT to understand?

This shows in the ridiculously-large rotating centrifuge module designs that have surfaced to answer this microgravity issue.  That is where the enormous rotating structures attached to non-rotating main ship structures come from.  These have entered popular fiction as the Earth ships of “Babylon-5”,  and the gigantic (but otherwise unexplained) vessel in “the Martian”.  We DO NOT need to do it that way!

What I showed was that this outcome is nothing but expensive gravy-train corporate welfare nonsense.

NASA has a preference for Boeing and Lockheed-Martin designs,  as evidenced by the 90-day report and some other recent egregious examples.  These reflect more a favored contractor bias,  than anything else.  It shows in the price tag,  too. 

That’s where the roughly half-a-trillion $ Mars mission price figure came from,  for nothing but a weightless-transit mission.  The mission re-worked for artificial gravity is supposedly even more costly. 

And yet,  we who have actually sized-out such missions already know that to be egregious bullshit.  As stupid as Congress has repeatedly demonstrated itself to be,  they at least nixed that price tag!

As for the development times necessary for artificial gravity,  it depends upon how you do it!  Cable-connected stuff has a very long development time (many years),  because we know almost nothing about the myriad ways that concept can go wrong,  and about how to prevent those outcomes.  Spinning this with some sort of bearing-and-seal to a non-spinning portion of the vehicle,  falls in exactly that same long development time / high expense /we have no experience category. 

Spinning one rigid item does not!  We have centuries of experience with this in all sorts of steam and internal combustion engines,  all sorts of windmills,  and all sorts of tire and wheel-balancing apparatuses since the dawn of automotive technology.  All we have to do,  is prove out some real spacecraft components while doing the confirmation experiments.  This is not at all the same as proving out the cable-connected stuff or the spin bearing stuff!  I’m sorry,  it’s just not! 

So,  Louis and I disagree on this issue. 

I think it is stupid to avoid incorporating spin gravity.  I also think it is stupid to do anything other than one single rigid spinning object. 

GW


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

Offline

#59 2017-09-03 03:54:44

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,893

Re: Space X - getting ready for Mars.

We cannot continue down the unlighted primrose path of assumptions regarding long term zero g effects. I'd say that NASA is tending to present a "Lawyer's Case" for the effects being insignificant. I, on the other hand, tend to think of the "Scientist's Case," wherein the complete lack of data for artificially produced gravity causes me to adapt a negative viewpoint until proven otherwise.

My proposed model for the Mars transit system (Not a single vehicle, but a connected cluster of them) utilized rigid structure between 2 "capsule" style modules with rotation about a midpoint of a subsequent "baton" architecture. We can wordsmith all of this stuff, but maybe a model maker among us could complete something that gives us a physical reality to gaze upon.

I consider NASA to be intellectually irresponsible in their continued neglect of the biological consequences of long term zero g. Maybe the first few flights will put the crews "at risk," but ultimately there will be a "battlestar galactica" with the bicycle wheel built and funded by...gasp...NASA.

Offline

#60 2017-09-03 04:39:32

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

Re: Space X - getting ready for Mars.

I agree long term we will develop artificial G - why wouldn't you?  But neither Space X nor NASA seem to have it as a priority and in that I think they are right.

Oldfart1939 wrote:

We cannot continue down the unlighted primrose path of assumptions regarding long term zero g effects. I'd say that NASA is tending to present a "Lawyer's Case" for the effects being insignificant. I, on the other hand, tend to think of the "Scientist's Case," wherein the complete lack of data for artificially produced gravity causes me to adapt a negative viewpoint until proven otherwise.

My proposed model for the Mars transit system (Not a single vehicle, but a connected cluster of them) utilized rigid structure between 2 "capsule" style modules with rotation about a midpoint of a subsequent "baton" architecture. We can wordsmith all of this stuff, but maybe a model maker among us could complete something that gives us a physical reality to gaze upon.

I consider NASA to be intellectually irresponsible in their continued neglect of the biological consequences of long term zero g. Maybe the first few flights will put the crews "at risk," but ultimately there will be a "battlestar galactica" with the bicycle wheel built and funded by...gasp...NASA.


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

Offline

#61 2017-09-03 09:58:00

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,077
Website

Re: Space X - getting ready for Mars.

Most of the mission designs I have seen proposed call for the crew to return home for a free return to Earth from the interplanetary trajectory,  which is the high-gee return at around 17 km/s relative to Earth that I spoke of. 

Some of these propose to bring the crew home in a capsule,  others a habitat module of some kind followed by a capsule return,  but all share 6-8 months weightless before that high-gee return.  No exercise is possible in a capsule,  some might be in a habitat module. 

If NASA's optimism about weightlessness is justified,  the crew will survive this return.  If that optimism is not justified,  the crew will die just as they arrive home,  as I have said.  Point is,  there is NOTHING to justify that optimism,  because not once in all these decades since Gagarin's flight has anyone spun anything in orbit to explore the therapeutics of partial gee.  Simple as that. 

My argument is this:  unjustified optimism about weightlessness is unethical.  Because it is unjustified and therefore unethical,  you do not go that route,  you address the issue conservatively,  which is to spin the Mars ship.  If that requires testing an item in LEO before we go (and it does),  then so be it.  Let's get on with that. It's a real "shit or get off the pot" type of thing.

What I also warned against was letting the favored contractors turn the simple spin gravity demonstrator into another multi-billion dollar space station.  Let Bigelow and Orbital do it instead.  3 to 5 such modules docked together and spun end-over-end could do this for under $1B.  You could even put crews aboard.  Show what 1/3 of gee might do to slow microgravity diseases.  Put fold-out decks in the B-330,  put stiffening framing and big electric-driven flywheels in the Cygnus.

And you don't need an SLS to do any of that! You don't really even need Falcon-Heavy,  although it would be helpful to fling those modules 2 or 3 at a time.  Falcon-9 and Atlas-5 can do this one-at-a-time,  for no more than about $90M per launch.  The modules themselves are under $100M each,  too.  This thing could be up there next year.  We could have the partial gee answers we need in just several months after it is up there.  And still do the unmanned debris impact and radiation-in-the-van-Allen-belts thing with it after we finish exploring partial gee with it. 

From there,  who cares whether the life support recycling efficiencies are as high as we might like?  If not,  just build the Mars ship a bit bigger,  stock more supplies,  and just go.  These life support efficiencies are just excuses not to go,  not real make-or-break issues.  And if you use my docked modules idea,  it is easy to just dock more modules together,  if you find that you really do need bigger. 

There really is method to the madness that I proposed.  A lot of it has to do with mission design flexibility.

GW

Last edited by GW Johnson (2017-09-03 10:09:20)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

Offline

#62 2017-09-03 16:56:40

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

Re: Space X - getting ready for Mars.

My point is that only an idiot would propose jumping in at the deep end.

We can do this is in stages.

Once Space X rocketry is a little more developed - next 2-3 years probably -  we could start Mars analogue mission testing. First off would be simple orbiting and circumnavigation of the Moon, for 8 months followed by performance testing on Earth. Next, we would build a hab on the Moon and test crew would live there for maybe 3 months to begin with after a 8 months of zero G.  Initially there would be immediate return to Earth, but then the time spent on the Moon would be extended to 6 months, a year and longer, and there would be a Mars return simulation.  The testing might extend over a 6 year period as part of a 10 year Mars Mission project. At the end of 6 years we would know if the optimistic analysis was justified or not.

On the question of return, can't we slow craft down gradually with month long orbits? And then use a strong retro rocket return craft (which would dock with the Mars return vehicle), so avoiding extreme G force?

GW Johnson wrote:

Most of the mission designs I have seen proposed call for the crew to return home for a free return to Earth from the interplanetary trajectory,  which is the high-gee return at around 17 km/s relative to Earth that I spoke of. 

Some of these propose to bring the crew home in a capsule,  others a habitat module of some kind followed by a capsule return,  but all share 6-8 months weightless before that high-gee return.  No exercise is possible in a capsule,  some might be in a habitat module. 

If NASA's optimism about weightlessness is justified,  the crew will survive this return.  If that optimism is not justified,  the crew will die just as they arrive home,  as I have said.  Point is,  there is NOTHING to justify that optimism,  because not once in all these decades since Gagarin's flight has anyone spun anything in orbit to explore the therapeutics of partial gee.  Simple as that. 

My argument is this:  unjustified optimism about weightlessness is unethical.  Because it is unjustified and therefore unethical,  you do not go that route,  you address the issue conservatively,  which is to spin the Mars ship.  If that requires testing an item in LEO before we go (and it does),  then so be it.  Let's get on with that. It's a real "shit or get off the pot" type of thing.

What I also warned against was letting the favored contractors turn the simple spin gravity demonstrator into another multi-billion dollar space station.  Let Bigelow and Orbital do it instead.  3 to 5 such modules docked together and spun end-over-end could do this for under $1B.  You could even put crews aboard.  Show what 1/3 of gee might do to slow microgravity diseases.  Put fold-out decks in the B-330,  put stiffening framing and big electric-driven flywheels in the Cygnus.

And you don't need an SLS to do any of that! You don't really even need Falcon-Heavy,  although it would be helpful to fling those modules 2 or 3 at a time.  Falcon-9 and Atlas-5 can do this one-at-a-time,  for no more than about $90M per launch.  The modules themselves are under $100M each,  too.  This thing could be up there next year.  We could have the partial gee answers we need in just several months after it is up there.  And still do the unmanned debris impact and radiation-in-the-van-Allen-belts thing with it after we finish exploring partial gee with it. 

From there,  who cares whether the life support recycling efficiencies are as high as we might like?  If not,  just build the Mars ship a bit bigger,  stock more supplies,  and just go.  These life support efficiencies are just excuses not to go,  not real make-or-break issues.  And if you use my docked modules idea,  it is easy to just dock more modules together,  if you find that you really do need bigger. 

There really is method to the madness that I proposed.  A lot of it has to do with mission design flexibility.

GW


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

Offline

#63 2017-09-03 17:25:17

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,686

Re: Space X - getting ready for Mars.

154 pages
Physiologically Constrained Aerocapture for Manned Mars Missions

I would not count on space x so soon as we would want as they are losing forward momentum with not working to make Red Dragon man capable flights and have dropped the sample return mission landing on mars as well. Would even bet that moon mission for the tourists that paid will be even put on the back burner soon.

This may stabilize a bit once the triple barrel falcon heavy is flying but thats going to take maybe a dozen such launches before they may go for the next step up the ladder.

As for mission testing for loops around the moon sure once we have the shielding and life support for what we would see onboard the deep space vehicle to make it happen will costs you.....

Offline

#64 2017-09-04 05:27:21

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,893

Re: Space X - getting ready for Mars.

I'm of the opinion that NASA's unwillingness to allow retropropulsive landings of the man rated Dragon 2 had an effect on the Red Dragon mission(s) as well as the manned tourist flight around the moon. It seems that NASA keeps erecting obstacles to getting out of LEO, either by hook or by crook. So...where inside the agency does reside the resistance? Is it simply the "not invented here" thing, or does it go deeper? The 2 "favored contractors" keep coming up with multibillion dollar schemes that don't accomplish much than getting astronauts a lethal dose of GCR and solar flare exposure.

Offline

#65 2017-09-04 08:59:19

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,686

Re: Space X - getting ready for Mars.

Another thing is that when we need something to be just a bit better than what we have Nasa sends out a new contract to make it and its not even compatible with what exists as its a totally new design under its famous contract plus methods.

Space x once it fires up its triple core will have taken a page out of Boeings rocket family book skipping a few launchers inbetween the Delta II and its Delta IV heavy model, It would be interesting if Lockheed had done the same but there Atlas V never went any further than a paper concept.

The fact that Space x is leveraging reuse makes it a better buy and will hopefully not change that as they launch bigger payloads.

Offline

#66 2017-09-04 09:14:22

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,135
Website

Re: Space X - getting ready for Mars.

There are some in NASA who feel humans do not belong in space. They feel exploration should be done exclusively by robotic explorers. Many within NASA, if not most, see space exploration only for science. They believe science can be done with robots, so we don't need humans in space. That's obviously wrong, but that's one major force we're fighting.

Another force is bureaucracy. The bureaucrats always add obstacles, always fear failure. If you watch the video for InSight, they emphasize heratage from previous missions. That's great, but they also emphasize low risk. That's become so pervasive within NASA that they blatantly admit it to the public, and even brag about it.
YouTube: InSight: Digging Deep with NASA's Next Mars Lander

Another problem is "Old Space" contractors. Corporate executives at Boeing and Lockheed-Martin don't see any value in NASA at all. They treat NASA as a means to funnel government money into their own pockets. They don't want to actually achieve anything, they want to manipulate anything NASA hires them to do in order to maximize revenue. Robert Zubrin talks about engineers being told to shut-up, that if NASA wants something then they can pay for it. After reading Dr. Zubrin's book, I spoke with several engineers who worked on Shuttle, at the time the Shuttle program was on-going. They all reported they came up with ways to reduce labour, to increase the flight rate and reduce cost. They all (*ALL*) report they were told to shut up. One engineer reported the manager said "you're taking food out of people's mouths". This is obviously stupid, if time to process Shuttle were reduced, they wouldn't reduce the cost per year, instead they would launch Shuttle more times per year. Now those same project managers and corporate executives are working on SLS and Orion.

Offline

#67 2017-09-04 13:53:05

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,686

Re: Space X - getting ready for Mars.

The current method of payment starts the problem with contracts for paying for a service versus having something already in orbit and Nasa wanting to make use of it.

As we have seen Space X, Boeing, Lockheed, Orbital ATK do all have the means to launch a payload to orbit with able to send cargo onboard a Dragon or Cygnus while Bigelow is in a trial phase for inflatable habitat building blocks.
The conversion of a cygnus is possible as they get there hertiage from the ISS modules from the say builder.

In Essence we are just waiting for Nasa contracts for anything beyond LEO to happen. I am reminded of the Field of Dreams saying that if you build it they will come and that is no difference with space.

Offline

#68 2017-09-05 03:32:52

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,893

Re: Space X - getting ready for Mars.

My take on NASA and cost-plus contracting takes the words of that immortal American philosopher, Forrest Gump and applies it directly:

STUPID IS AS STUPID DOES.

Offline

#69 2017-09-05 09:13:12

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,077
Website

Re: Space X - getting ready for Mars.

Actually, there is a proper place for cost-plus contracting.  Unfortunately this is widely misused in the space industry as well as defense work in general,  for purposes of corporate welfare.  Letting these companies agglomerate to monopolistic giants has created greedy pigs that do nothing,  but they do require corporate welfare just to continue existing at all. That is exactly where "stupid is as stupid does" is the most accurate description possible. 

Cost-plus is entirely appropriate when exploring something never done before.  Such things are not amenable to the usual management controls,  because it is impossible to reliably identify milestones and costs,  precisely because it has never been done before.  This is better done with smaller scope items,  so as to control the damage,  if it turns out to be a harder thing to accomplish than is usual.

Building a chemically-powered rocket to do a job is not a suitable cost-plus project.  Doesn't matter if it's bigger than anything previously. Chemical rocketry and all its supporting and related technologies are well known to us.  Chemical rockets have been built before.  We know what the milestones are,  and about how much effort is required to succeed.

Building a self-contained and self-supporting ecology as a life support system for a Mars colony does qualify for cost-plus efforts,  precisely because much of that is still quite unknown to us.  Some on these forums will disagree with that statement,  but I speak the truth.  That attempt in Arizona a few years back failed,  because we as yet do not know fully what we are doing.  If funded in pieces,  those which are known to us should not be cost-plus,  those that are unknown,  should be cost-plus.  Integrating and demonstrating all these pieces should be done with a sort of combination funding,  to allow for the unknown rearing its ugly head.  Which t will,  that's Murphy's Law.

GW

Last edited by GW Johnson (2017-09-05 09:14:21)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

Offline

#70 2017-09-05 09:55:52

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,893

Re: Space X - getting ready for Mars.

In post #66 of this thread, Robert did hit on something that is very true: many scientist types don't believe in manned space flight, and are absolutely (and wrongly) convinced that robotics can do everything necessary to "do science' on Mars. I have a very good friend who is a lead scientist at the NIF (National Ignition Facility) at Lawrence, Livermore National Laboratory, with whom I've had many discussions (OK, arguments!) on this topic. When I start talking about drill rigs looking for subsurface water, he envisions a robotic drill system that might be able (on a good Sol) manage to drill down 3 to 5 meters. I think in terms of oil drill rigs requiring crews of 60 men to drill down 7 to 10 Kilometers. That cannot be robotic. We've done almost s much as we can ask from robotics; it's now long past time for human exploration!

Offline

#71 2017-09-05 13:21:00

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,135
Website

Re: Space X - getting ready for Mars.

In 2002 the president of the Canadian Space Agency proposed a Canadian Mars Rover. A Canadian mining technology centre developed a multi-segment drill for this rover: 10 segments at 1 metre each. They tested it in a box of mixed materials: hard rock, soft rock, gravel, sand, clay. The drill took hours to go through 2 metres, but went right through everything including the plywood bottom of the box. Powered by electricity, without any lubricant (dry drilling) so appropriate for space. Unfortunately Canadian Parliament didn't approve funding. My point is a robot could drill down to 10 metres, but that's it.

Offline

#72 2017-09-05 19:43:42

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,686

Re: Space X - getting ready for Mars.

While I agee with you all that we are nearing the point where robotic missions will just not due anymore we are also that a pint where corporate businesses must stick there own head out and take risk in putting something else in orbit or in a mission plan that goes somewhere. The must happen issue is to make jobs in space and to bring the boot strapping of supply for them along for the ride as a function of seeding from LEO outward.

Offline

#73 2017-09-06 00:38:33

Oldfart1939
Member
Registered: 2016-11-26
Posts: 1,893

Re: Space X - getting ready for Mars.

SpaceNut-

In that regard, only SpaceX driven by Elon Musk seems sufficiently motivated.

Offline

#74 2017-10-14 21:47:15

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,686

Re: Space X - getting ready for Mars.

Offline

#75 2017-11-02 02:34:31

elderflower
Member
Registered: 2016-06-19
Posts: 1,260

Re: Space X - getting ready for Mars.

On the question of propulsive landing.
Thus far landings of large stages have taken place on prepared pads or barges. The latter seems to work even when the vehicle is burning! Only small devices have been landed on rough ground and regolith, eg Lunar lander module and small rovers, The last one used a skycrane device. Large rockets will have very large exhaust volumes at high velocity which will blow rocks, sand and dust a long way. The first arrival will be fine with that, it will just clear an area around its landing spot. Subsequent landings cannot be made close to the first, we cant have flying rocks or sand blasting damaging the reuseable earlier vehicles. So there must be a radius where this problem is minimised which will depend on gravity and atmospheric conditions. The problem recurs when the reusable craft departs, using a lot more thrust than when it landed, exposing remaining craft and structures to damage from this cause. Unlike earth launches there won't be a prepared pad with hold downs and exhaust ducts. It will just be lightup and go!
Having established a safeish radius, refuelling will need hoses/pipework long enough to reach from the fuel production point to the receiving vehicle and transfer pumps to refuel in a reasonable time to avoid excessive boil off. The only alternative that I can see would be for each early lander to contain its own fuel and LOX plant independently.

Offline

Board footer

Powered by FluxBB