What's missing to get humans to Mars? - Orbit 11.28


#61

Don’t forget, once settlers started crossing the ocean, entire families went together and yes, many died, but they considered it worth the risk. When talking colony instead of research station, we have to think in terms of people of all ages and backgrounds.


#62

indeed but lets face it. it will be research first colony later espcially if the first trip is govenment funded.


#63

Maybe not music, but certainly a global timestamp for all systems to synchronize to.


#64

Sorry, i used the word Tether when I meant “to attach”. I belief that there must be landing feet on the BFR and these can be "clamped/connected " together by some mechanism easily enough.

With the height of the BFR spinning at 3 revolutions per min the “gravity” would be from about the same as Mars at the tips to about the gravity of the moon at the cabins…


#65

As for the VLF, You could have a post only “tweet board” that the whole solar system can see/hear :slight_smile:


#66

Climate change is real … Yeah … hopefully we get a chance to fix it …


#67

So here’s everything you ever wanted to know about perchlorate:

It is used as a medicine (known as goitrogen), and it has been well studied. In the body, it competes with Iodine for uptake by thyroid cells. These cells need Iodine in order to make systemic autonomic control hormones that regulate metabolism. The protein in charge of transporting Iodine into the cell is 30 times more likely to transport perchlorate than Iodine, so it is a very strong inhibitor of uptake. Even so, our bodies usually take in enough iodine (due to Iodine fortification efforts) that small quantities of perchlorate do not matter. Larger, chronic exposures can cause Iodine uptake to be so limited that the thyroid will grow larger (trying to create more tissue to pull in more Iodine). This is known as a goiter, and was very common in certain areas of the US before Iodine fortification of human and cattle salts was begun.

Iodine
The daily recommended uptake for Iodine is

  • 150 microg/day

The tolerable upper level for Iodine in the general population is

  • 1,100 microg/day
    … though much larger doses can be tolerated by most people for short periods

Perchlorate
California’s “action level” for perchlorate groundwater contamination is

  • 37 microg/day (which is roughly .0007 microg/day per kg of body mass or 18.5 microg/L of water)
    … This limit is based on the lowest dose known to cause a change in Iodine uptake.

Lowest level shown to cause a noticeable drop in thyroid stimulating hormone (TSH) is

  • 2640 microg/day (this level is “pre” hypothyroidism, it wont cause disease but it does indicate the potential)

Lowest levels shown to cause a drop in thyroid hormone release is

  • ? (couldn’t find a level, but this would be the first actual disease causing state: hypothroidism)

Levels used in 1980s to fight Graves Disease, which causes an overproduction of thyroid hormones

  • 900,000 microg/day (several women died at this dosage, but that may have been a complication of Graves disease, medication was given over a period of 1 year)

Several studies of workers with long term (up to 6 years) exposure to high perchlorate amounts found no damage to workers’ thyroid function at doses averaging 30 micro/gram per day and peaking at over 600 micro/gram per day.

As for Mars, because Iodine is a competitor to perchlorate, increased intake of perchlorate can be countered by increased intake of Iodine. As long as a decent balance is maintained, thyroid function appears to be able to tolerate a fairly wide range of intakes of the two ions (in people without thyroid issues). Thus you could think of Iodine supplementation as the “treatment” to perchlorate poisoning.

Iodine should be easily available on Mars in the needed quantities, since so little is needed by the body. Because it is also used in many chemical reactions and tests, a sufficiently large store will likely be sent to Mars on the first rockets, where it will take almost no space or payload mass.

One poorly studied group that may be of interest in a later stage Mars colony is pregnant women. Because of the mechanics of transporting Iodine or thyroid hormone to a developing fetus and breastfeeding infants, perchlorate may be even more inhibitory for the child. Also, developing fetus and newborns are much more reliant on thyroid hormone for proper development and there are many horrifying consequences of insufficiency. There was a study of pregnant women in Israel who were consuming around 350 microg/day of perchlorate (via tap water) and were breastfeeding, but neither child nor mother showed no signs of thyroid dysfunction. These numbers are promising, but there is still a potential vulnerability here. Again, Iodine can be used to counteract the problem for newborns, the trick for doctors and parents will be maintaining the balance.


Pearce, E.N. Diagnosis and management of thyrotoxicosis. BMJ, 332(7554): 1369–1373. 2006 Jun 10. ( Diagnosis and management of thyrotoxicosis )

Leung, A.M., E.N. Pearce, and L.E. Braverman. Perchlorate, iodine and the thyroid. doi: 10.1016/j.beem.2009.08.009. Best Pract Res Clin Endocrinol Metab, 24(1): 133–141. Feb 2010. ( Perchlorate, iodine and the thyroid )

Leung, A.M. and L.E. Braverman. Consequences of excess iodine. doi: 10.1038/nrendo.2013.251. Nat Rev Endocrinol, 10(3): 136–142. March 2014. ( Consequences of excess iodine )


#68

A quick word on “remediation” of perchlorates.

Removing any contamination from ground water is extremely difficult because it is stuck in the fissures that water flows through and locked into the structural matrix of the rock itself. On the other hand, surface deposits of perchlorate would be easily washed out, since the ions are loosely associated with the particles and “flush” water can be washed through the fine powers of the the Martian surface easily. As such, Earth’s ground contamination is probably not a good comparison to the Martian situation in this regard.

There are a number of microorganisms who actually metabolize perchlorate as a source of energy. A Mars settlement could use these creatures in a bioreactor to remediate large amounts of regolith.

As for dust contamination of the settlement interior, some have speculated upon the idea of using “fixatives” in the airlock. For an example of a fixative, just look at “Fabreeze.” It is a mixture of water and corn starch which, when sprayed on a surface containing loose particulates and dust and given time to evaporate, will “affix” the particles together or to the surface by forming chains of dried starch over and through them. Such a system could be built into airlocks (it could even be as simple as a spray bottle), allowing those who are ingressing to lock down dust contamination onto their suit and the walls and floor of the airlock before proceeding. That would cut down greatly on contamination, but in the long run would require a local source of starch (probably potatoes).

Indeed, stronger fixatives could be sprayed all over the area around a settlement to lock the local dust into place. This could prove beneficial for reducing dust ingress into the habitation areas and to keeping dust off solar power collectors also.


#69

Actually, as long as you can damp out waves which are caused by the movement of mass at the end of the tether (using say… a set of reaction wheels), it could work. You might need 3 or 4 parallel tethers lines though, like on a puppet or a marionette.


#70

“So here’s everything you ever wanted to know about perchlorate:”

Good work done there… !
It sure will help the Mars missions knowing these research bits…

Another thing I found with Perchlorate poisoning, is it seems reversible ie. the body can wash it out in time and repair itself… so for people effected it may be good to have a “Perchlorate free zone” in the community dwellings where people effected can recover for a few months. That would mean that this PFZone needs to be designed and implemented ASAP in the dwellings infrastructure.

Maybe some onion ring Zones where the central areas are PFZ and the outer zones get progressively more relaxed. This may dictate the types of habitats that gets implemented. and it may mean that most of the current standalone proposed 3D printed structures may not be good. They may be good to start the outpost but for the structure that houses the main community as it grows, some other design may be needed. Maybe something like a VenusProject circular layout will be a good scheme.

One of the proposed build schemes, shown bellow, could be a good starting point. May not look as pretty but would seem to me to be a more controllable environment… as time goes on maybe the central areas can be domed over to provide more areas for hydroponics, or more radiation protection. or excavated to make more space below…

Team: Rustem Baishev
One day Mars will become as an ordinary destination as our own Earth’s continents and cities. In such case expandability is the main consideration, for which the most suitable...


#71

Was thinking about this “tethering” strategy a bit more…

Since the BFS can be lifted up onto the BF Booster by its nose tip as shown by the simulations we have seen. Then attaching a tether to the nose tips would be no problem.

I would propose a kind of funnel shape muzzle for the tip of the BFR.

The skirting of the funnel can cover the safe region(tip of the BFR) and can be fairly thick say 20cm to provide even more radiation protection to the radiation shelter area.

The funnel extends for 50m and joins to the other BFR. I propose that the tether be a hollow Kevlar tube made up of a ring of smaller tubes. About 2m in diameter. all the tubes can be inflated (bouncing castle?) to give it some structure and dampening. The whole tether can even be used as a “tunnel” to move stuff and people between the 2 ships!

A 50 m tether with the 2 ships spinning at 3 rpm would give a “gravity” of about 1/4 g and at the cabin areas a bit more than 1/3 g. At the rocket engines, about 1/2 g so there wont be any stresses beyond what the BFR can handle. Everything is “right way up” unlike attaching 2 BFR by their legs.

One issue would be the solar panels which are deployed just above the engines. They will need to be able to handle the 1/2 g at that area.

Arriving at mars the tether can be left orbiting Mars(an attached ion thrust engine would be enough to maneuver it into orbit and keep it orbiting) to be reused by ships returning to Earth.


#72

That’s while it’s empty (and possibly unloaded) though. With some fuel in the tank and the cargo full the stress might be higher than the attachment point can handle.

The solar panels would also have to continually turn to face the sun. This is one of the major engineering challenges which has so far prevented rotating spacecraft.


#73

Good point… although it would only be 0.5 g at the bottom and 0.25 g at the top which should make the whole spaceship “weigh” about 0.35 of its actual weight on earth. I am sure we could spin it at a lower rate if needed once the engineering types do all their calculations :slight_smile: maybe 0.15g at the top and 0.3g at the bottom reducing the load to 0.2.

Hmm… cant see that as a problem… wouldn’t you just span the solar cells like a section of a virtual pancake and spin the 2 ships like a spinning virtual pancake that faces the sun ?


#74

Also the ISS currently has solar panels that continually turn to face the sun… How is something we already know how to do and have had built and working for 2 decades now a barrier to a spinning station or ship?


#75

I’m unsure of the system the panels on the International Space Station use, but I’m confident they don’t operate at the loads and the duration that a rotating station/ship would require for 1G. That’s radically different. I really really really want to see spinning/tethers for crewed flights investigated more.


#76

The IIS needs solar panels to change direction because the IIS always orients towards earth … not the sun. That wouldn’t be a problem for a vehicle traveling through space to Mars.

Just envision a spinning pancake flying to mars, the pancake can be set to be always facing the sun. the orientation is independent of the direction its moving.


#77

I am only proposing for it to be 0.5 G and it can possibly be reduced to 0.3 G. furthermore the deploying struts can be orientated to reduce the stress further or have it attached to the side of the ship. i will see if i can sketch something up :slight_smile: )

Spin_BFRs

so you will be looking at it top down … or like your eyes are the sun…


#78

placement is key. The ISS style panels could be used without issue or modification if attached to the hub portion of a spinning station or ship. One would not want to use such a system at the extremities of the spinning section.

But like @Tobi_Foong is saying more rigid panels could be placed on the sides of a spinning ship and you just orient the ship so that side faces the sun.

The tether system using BFRs poses issues though as the panels have to deploy from the BFRs… so in the nose tether method the panels would be under the most stress. With engine to engine they’d be under less stress… but the best solution would be if you could remove them and clamp them on to the midpoint of the tethers themselves.


#79

Hmm… Just had a thought… … why not have the tether be solar panels ? since my proposal would be an inflatable cylinder why not inflate a flat panel. Solar panels can be made very thin these days… even painted onto surfaces! … so why not have the BFR itself be painted with solar panels :slight_smile:

PS: I am sure it can be done… have it roll out like a PartyHorn blower thingi from the tip of the BFR radiation protection funnel… and connect it to the other BFR PartyHorn. If the BFR itself has Solarpanels on the body then the tether solar panel wont need to be as large.

LOL imagine a BFR with a party horn on the tip LOL :sweat_smile:


#80

Conservation of angular moment says, that your facing will change as you orbit. In 1.5 months you will be 45 degrees off target, in 3 months you will be perpendicular to incoming light (for an Earth orbit).