Mars Architecture

[holmec]

From the recent article<br />http://www.space.com/news/060803_griffin_mars.html<br /><br />Griffin notes he would make a study to figure out how to get to Mars. <br /><br />I have one suggestion. In making a "ship" (CEV and other modules) that travels from earth to mars and back with the crew, make the "ship" in such a way that while you cruise the "ship" turns on an axis to have artificial gravity (ie centrifical force) so the crew will keep their bone mass.<br /><br />You can design it in many ways, but I think the operational goals to use artificial gravity while cruising and not while docking operations and maintenace operations would be simple enough to not need motors to spin only parts of the craft. Spin the whole craft. <br /><br />For instance, if you design the modules in a classical cylindrical or linear fashion (like we have been doing [Apollo, Soyuz, Shenzou] all you need to do is design the module with a floor on one side and then have a counter weight extend from the middle of the linear configuration and spin the whole thing. If you do it right the interior of the modules will have a floor that the astonauts can walk on. <br /><br />The only other thing is to adapt the camera views for the spin. for forward and rear views you can make a viewer on a pc or laptop spin the piture at the appropiate rate, and for lateral views you can use stop action type of algorithym to see clearly.<br /><br />To me this seems to be an elegant solution to the complicated problem of bone loss of astronauts during long missions. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[christine16]

very interesting idea !!!

 

[qso1]

Variations of this idea have been proposed as far back as the 1969 Von Braun plan in which a tethered gravity generation system was proposed for a Mars vehicle then. As always, its not the lack of ideas, or ability, its the relative lack of money in this case. It's simply cheaper to build a craft that does not spin than it is to build one that does.<br /><br />If the current bone mass loss study leads to other studies that bone mass loss in zero "G" is too severe to tolerate on a mars mission. Then there will be no choice but to have an artificial gravity vehicle for the transit in which case, what you propose could well be incorporated on a future mars vehicle. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[cuddlyrocket]

Due to coriolis and tidal effects, the astronauts have to be a substantial distance from the axis of rotation. That would make any craft with the axis of rotation inside it unfeasably large. The only possibility is the Mars Direct approach where the craft is connected to a long tether with a counter-weight at the end which is then set rotating.

 

[JonClarke]

However all the evidence from near 30 years of long duration space flight (~40 mission) is that 6 months in zero gravity do not lead to unacceptable bone loss and people can fly multiple missions of this (and great) duration. There is no need to add the complication of spin gravity to the list of Mars mission requirements.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[holmec]

>Due to coriolis and tidal effects, the astronauts have to be a substantial distance from the axis of rotation. That would make any craft with the axis of rotation inside it unfeasably large. The only possibility is the Mars Direct approach where the craft is connected to a long tether with a counter-weight at the end which is then set rotating.<<br /><br />Do you happen to know the minimal distance from the fulcrum?<br /> <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[holmec]

>However all the evidence from near 30 years of long duration space flight (~40 mission) is that 6 months in zero gravity do not lead to unacceptable bone loss and people can fly multiple missions of this (and great) duration. There is no need to add the complication of spin gravity to the list of Mars mission requirements.<br /><<br /><br />So therefore on a Mars mission you have to land all the astonauts on Mars.<br /><br />The problem is we have not tried two six month trips with some time in 1/3 G environment in the middle.<br /><br />I think the jury is still out. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[qso1]

Ultimately that will be determined by whatever bone mass loss research of maybe the next 15 years, in addition to the last 30 years finds. I tend to think as your stating that we will probably not require a ship to have artificial gravity. Especially if some variation of VASIMR is utilized for propulsion which would cut the transit times down. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[JonClarke]

It's a manageable problem now. Whatever advances the next 15 years bring will make it even less of a problem.<br /><br />Who needs VASIMR? It's not necessary technology for getting to Mars. It adds complexity, mission mass, cost and risk.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[holmec]

So here is the question!<br />How does the Coriolis effect affect a human??? Does it make him dizzy? <br /><br />In other words what harm does the Coriolis effect do?<br /><br />I remember seeing a documentary where part of it was a NASA experiment that made rodants live in a 2G and 3G environment in a cetrifuge that was not very large. And apparantly the animals adapted.<br /><br />So what harm can the Coriolis effect do?<br /><br />About the amout of G force. How about the same as Mars in going and a little more in coming back? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[josh_simonson]

That bone loss study was with regards to radiation, not the lack of gravity. In which case artificial gravity is moot and ISS research is useless. <br /><br />We'll find out how bad it is and how hard it is to deal with only by putting people outside the magnetic field, such as on a lunar outpost.

 

[yoda9999]

Perhaps the astronauts only need to spend a minimal amount of time in a gravity environment. To save money, just attach a small module at each end of a centrifuge. The rotation axis along the length of the ship. Most of the habitat would be outside these small modules. Astronauts can take turns spending time in them.

 

[j05h]

The two artificial-G scenarios that make the most sense: the "bike-centrifuge" that NASA tested recently, fitted in a Bigelow-type inflatable. Or Zubrin's Hab-and-3rdStage proposal. I agree that g-losses shouldn't negate a Mars mission even without spin-G.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[JonClarke]

"So what harm can the Coriolis effect do?"<br /><br />High spin rates disorientate the person experiencing them. The crew would not be able to function effectively. <br /><br />Low spin rates are engineeringly complex. In other words costly. They still would require adapatation from the crew and reapatation afterwards. We have no idea how long this takes or how well people do it.<br /><br />Insisting on spin gravity is a gerat way to add 10 years to your development time line.<br /><br />Jon<br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

"That bone loss study was with regards to radiation, not the lack of gravity. In which case artificial gravity is moot and ISS research is useless."<br /><br />That bone study was a beat up. It involved radiation doses several times what would be experienced on a Mars mission. And ISS research is relevant, radiation doses are equivalent to that experience on the Martian and Lunar surface, and about half what is experienced in interplanetary space.<br /><br />The earth's magnetic field does not provide much shielding against cosmic rays. That comes from the atmosphere. The magnetic field protects against solar radiation but that is easily countered by good spacecraft design.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

Exercise in a human powered short arm centrifuge is very promising. Becuase the subjectsdon't move round and can wear vertical reality head sets the disorientation normally experienced by high spin rates is minimised. Spin gravity of up to 2G can be generated by a human powered centrifuge with a radius of <2m.<br /><br />It's just one of several very promising etchnologies for zero G mitigation that has yet to be tried on long duration spaceflight. The others include ultrasonic simulation of wight bearing bones (very succesful for osteoporosis suffers on earth, and negative pressure treadmills (tiraled on at least one shuttle mission, I believe. <br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[PistolPete]

<i>If you were facing in the direction of spin, and you bent over quickly, you would fall on your butt.</i><br /><br />True, for the first few days or weeks, but after that it's like gaining your sea legs, you get use to it and subconciously ajust. <div class="Discussion_UserSignature"> <p> </p><p><em>So, again we are defeated. This victory belongs to the farmers, not us.</em></p><p><strong>-Kambei Shimada from the movie Seven Samurai</strong></p> </div>

 

[yoda9999]

I think if the astronauts have to exercise more, they have to eat a lot more. To prevent loss of muscle and bone. That means more food needs to be brought along.

 

[qso1]

JonClarke:<br />Who needs VASIMR? It's not necessary technology for getting to Mars. It adds complexity, mission mass, cost and risk.<br /><br />Me:<br />Its not that its an absolute necessity but it would be kind of nice to know you could get to Mars a lot quicker. And keeping in mind I'm talking VASIMR derivitive...not VASIMR itself so we cannot be certain how much mission mass or complexity it will add. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[JonClarke]

Thewy would not have to exrcise more than they do now. The challenge is how to make the exercise more effective so they can spend less time at it (1 hr per day rather than 2 or more). Food mass is actually quite trivial, about 1 kg kg dry per day per person. So 900 kg over the duration of a 900-day mars mission, 4.5 tonnes for a 6 person crew, less than 2% of the mass sent to Mars with semi direct architecture (~270 tonnes).<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

Sure its nice to know that we know that there are technologies than might enable 4 month trips to Mars eventually. <br /><br />But what is the benefit of such a shortened trip compared to the development cost? What circumstances would make the the investment worthwhile?<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[qso1]

At the moment we don't really know. First off, if we were developing a Mars craft today, then VASIMR type propulsion might not offer advantages over NTR or chemical.<br /><br />But going to Mars is still at best, 20 years or more away. In that time, private industry might change the access to LEO, by bringing down costs, enough to justify the VASIMR type propuslion system development. Among the circumstances that might make the investment worthwhile, reduced transit times means reduced exposure to potential solar flare activity and if future studies reinforce the current one on bone mass loss. Then a combination of excercise, short transit times, diet, ect. could justify the investment.<br /><br />Once again, I don't think we are really ever going to send anyone to Mars...not the U.S. anyway because we have become a society too concerned with how much we spend on NASA human space flight while deficits run rampant.<br /><br />Humans to Mars has been on hold since 1972. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[holmec]

Where is the data? Where is the study. I can only conclude that on this subject everyone is just GUESSING!<br /><br />More research should be conducted.<br /><br />I tend to agree with Pistol Pete. Why can't the crew adapt to such an environment? Is this an inner ear problem?<br /><br />Hold on a second.<br /><br />It just occured to me that a centrifuge less than 1G is not possible on Earth. So therefore there has been no studies on this at all, and some who say they know some fact may know from any 1+G environment in a centrifuge experiment conducted on Earth.<br /><br />So I suggest there should be a study on less than 1G centrifuge on crew members in orbit for days. That might seem costly, but I bet it will yield very useful infomation about bone loss and crew funtionability over long periods of time. I bet we may find that at less thatn 1G we find a rate, distance to fulcrum combination that works for long space travel and ship/module construction. I guess the key is finding the right combination so the inner ear readings by the brain are minimal so the brain can interpret them so the crew can adapt and function. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[holmec]

>High spin rates disorientate the person experiencing them. The crew would not be able to function effectively.<br /><br />Low spin rates are engineeringly complex. In other words costly. They still would require adapatation from the crew and reapatation afterwards. We have no idea how long this takes or how well people do it. <<br /><br />How do you know this?<br /><br />Can you please elaborate on crew ineffectiveness. What does it do to the crew? They can't sleep? read? chew gum? they fall? disorientation? what?<br /><br />Why would low spin rates be costly? It seems there's more myth than study on this. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[holmec]

>Thewy would not have to exrcise more than they do now. The challenge is how to make the exercise more effective so they can spend less time at it (1 hr per day rather than 2 or more). Food mass is actually quite trivial, about 1 kg kg dry per day per person. So 900 kg over the duration of a 900-day mars mission, 4.5 tonnes for a 6 person crew, less than 2% of the mass sent to Mars with semi direct architecture (~270 tonnes). <<br /><br />Right! <br />I thought of a possible other way. Make a suit that gives resistance to legs in such a way to simulate a person's weight. So the astornaut will get excersise while working. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>