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#101 Re: Human missions » Yet another Mars architecture » 2020-02-22 07:41:49

Clearly the fuel issue is key. Starships are capable of shipping a few people, habitats, exploration equipment and 4 years of survival supplies to Mars. They are not capable of getting back without ISRU.
When is the ISRU test unit going to be installed on Mars, with its acre of solar panels or other power source? Without a tried and tested fuel source any visit to Mars is going to be a one way trip.

#102 Re: Human missions » Yet another Mars architecture » 2020-02-21 03:59:22

Re Starship , GW. What constitutes a colony? There weren't many people in the ships that set up the early European colonies in Eastern North America. They depended initially on resupply from the home countries and on the native populations until they were able to support themselves by agriculture. I don't see early Mars settlement being much different, apart from the scarcity of natives.  Starship would be sufficient to perform the initial settlement, support and evacuation (if needed) roles provided, as you say, that huge quantities of fuel can be manufactured on Mars.

#103 Re: Life support systems » Food! - Marsians=vegetarians? » 2020-02-11 12:51:35

Cannibalism brings all sorts of risks with pathogens and parasites. Another human is a great way to culture such things so consuming them is not smart!

#104 Re: Interplanetary transportation » Orbital Mechanics » 2020-02-11 12:26:17

We rarely need to consider the third body for our Mars or Moon, or even large asteroid expeditions, due to the fact that our space vehicles are very small in comparison with these bodies and with Earth. This means that the ship has a negligible effect on the first and second bodies.

#105 Re: Interplanetary transportation » COTS - status » 2020-02-11 12:03:24

Boeing's procedures for software preparation and testing might seem a little shaky!

#106 Re: Exploration to Settlement Creation » Construction technology for Mars? » 2020-02-11 11:59:38

ECTFE and similar polymers require a supply of Fluorine containing rocks to be located, mined and processed. I assume there will not be much difficulty getting Chlorine from the regolith, even if there are no massive salt deposits to hand.
The availability of Fluorine came up in the discussion on terraforming using greenhouse gasses.

#107 Re: Human missions » International Space Station (ISS / Alpha) » 2020-02-11 11:50:02

KBR is a large industrial contractor, if I am thinking of the same one.

#108 Re: Human missions » Carbon Monoxide - a way to power Mars? » 2020-02-11 11:42:28

CO is a cryogenic gas with physical properties similar to O2 or N2. Storage is therefore not very difficult. It is a usable fuel gas with O2. Specific impulse in a rocket is limited because of its relatively low heat of combustion (2CO +O2 >2CO2) but could be a useful energy source for surface equipment or for a hopper or flying machine on Mars.

#109 Re: Life support systems » Food! - Marsians=vegetarians? » 2020-01-28 16:48:13

When there are animals they will probably start with birds to make eggs and/or fish, molluscs, or crustaceans. All of  the latter are cold blooded, so much more efficient in converting food into meat. Mammals, other than people, will be way down the list. I don't suppose that cannibalism will be an option except under the most extreme circumstances.

#110 Re: Life support systems » Optimal air pressures.. - Which is best? More O2 or more pressure? » 2020-01-28 16:04:05

Bolbuyk probably should have said Argon rather than Helium. It has about the same abundance in Mars atmosphere as Nitrogen and would be just as good as a buffer gas.
The low partial pressure of nitrogen, though, might make life difficult for nitrogen fixing bacteria, and we are heavily dependent on these, particularly where we don't have industrial nitric acid or urea plants.

#111 Re: Life support systems » Sewage treatment » 2020-01-28 15:56:23

Your waste should be run through a digester or composter to reduce the chances of transmission of pathogens.
Also you need to avoid a totally closed loop whereby the crew generate waste which is then used to grow plants that are the major input into their diet. This loop can result in ever increasing levels of toxic material or ever decreasing levels of needed nutrients. Discarding a small percentage and introducing some material from outside sources will combat these closed loop effects.

#112 Re: Human missions » Carbon Monoxide - a way to power Mars? » 2020-01-28 15:31:29

Carbon monoxide liquid is a cryogen similar to LOX. CO can be burned with oxygen to generate heat, drive a heat engine (maybe a gas turbine) or even to power a rocket. It isn't great rocket fuel but it is relatively easy to make and store.

#113 Re: Space Policy » Starlink - astronomers complain ! » 2019-11-21 14:54:34

In my opinion the Sun will say anything that it thinks will sell newspapers. I think it (and other similar papers) make up a headline knocking something, then go out and find some disgruntled expert whose words can be interpreted as supporting the initial thesis. Take all newspaper reports with a pinch of salt!

#114 Re: Martian Politics and Economy » Lunar Nickel Mining » 2019-11-21 14:44:08

Without an atmosphere, meteorites will impact directly on the surface melting rocks and themselves. Your problem then becomes one of extracting useful minerals from frozen impact melts. Maybe from glasses like those observed by the Chinese lander. In such deposits the FE and NI will likely be present as oxides, silicates, aluminates and so on. On a body without an atmosphere there is little chance of finding a metallic meteorite. One was reported as having been found on Mars and several have been found on earth, for example the Cape York meteorite which was stolen from the Inuit.

#115 Re: Martian Politics and Economy » Lunar Nickel Mining » 2019-11-20 11:53:14

This process used Laterite ore, which you wont find on the Moon, although it might work on a different ore which you might find. It also consumed Calcium Fluoride (fluor spar) and Calcium Hydroxide (slaked lime) and coal all of which are going to be difficult to ship in industrial quantities.

#116 Re: Interplanetary transportation » Forget NTR, SEP is the Future » 2019-11-20 11:32:28

I suppose that most of the inbound fuel burn will be used in attaining and circularising the orbit and exhaust condensate isn't likely to impinge on Phobos. The return launch burn might settle there to a greater degree but you then have no vehicle to refuel unless there are regular Phobos missions.
I think the initial four shipments will take hydrogen so that methane fuel and LOX can be made without mining, per Zubrin. For 1100 tonnes of propellant you don't need all that much Hydrogen, about 55te for stoichiometry.

#117 Re: Science, Technology, and Astronomy » Hydrogen Production Moving to Mainstream Green solution » 2019-11-19 16:25:05

For a liquid fuel, it is easy to manufacture methanol which will work in most of our liquid fuelled devices with relatively minor modifications and which can be reformed to give Hydrogen and CO. The CO is burned to heat the reformer and the hydrogen is fed to a fuel cell for electricity production. CO2 is released and must be recaptured.

#118 Re: Martian Politics and Economy » Lunar Nickel Mining » 2019-11-19 16:07:31

Nickel and Iron can be extracted and redeposited using Carbon Monoxide. You don't need to electrolyse them.

#119 Re: Interplanetary transportation » Forget NTR, SEP is the Future » 2019-11-19 12:44:09

But direct entry saves a big fuel burn on arrival to get your vehicle into orbit.
If you do put it into orbit you may find it convenient to leave some part of it there and deorbit less mass than you otherwise would.

#120 Re: Exploration to Settlement Creation » How quickly could you build a self-sufficient community on Mars? » 2019-11-19 12:32:03

This plant may be using a lot of scrap iron and steel as feedstock.  Not sure 'cos Bloomberg's website didn't want to talk to me. And my German is limited to Zwei bier bitte kind of thing so I can't tell from Voest Alpine Stahl's site.
It does seem to manufacture strip and wire and plate, not hot rolled sections or pipe, but strip and plate can be cut and welded to make structural materials.

#121 Re: Human missions » Colonisation denial » 2019-11-16 10:08:09

Terraformer. What I think is missing is an experiment at Mars gravity. It can be done on a rotating satellite convenient to Earth. I think that would be better than waiting until we are 4 or 5 months away from home before we test such critical questions. If foetal/infant development doesn't work at 0.38 g in primates any Mars colony gets much more difficult.

#122 Re: Interplanetary transportation » A Reusable Lunar Lander » 2019-11-14 06:59:38

Right Spacenut. The lander has to be designed to use the fuel which can be made at its destination, for its approach and landing, or to carry some kind of conversion kit or to carry a separate engine.
In all cases the oxidiser is likely to be LOX which can be extracted from regolith minerals, but could be peroxide which can be made from locally obtained ice.

#123 Re: Human missions » Colonisation denial » 2019-11-14 06:46:35

Well there are plenty of mammals living in a weightless environment for their entire lives. They get pregnant and have live young. Whales and Sirenia never get out of the water, unless something goes drastically wrong and then they usually die.
The human foetus develops in an amniotic fluid filled sac like those of all other placental mammals and so are in a weightless environment until birth. A baby which presents in normal orientation at birth has exactly the same development as one that has a breech presentation (upside down), although the breach baby is at greater risk of complications during the process. All this indicates to me that gravity during pregnancy would play a minor role, if any, in determining the foetus' development so that pregnancy on Mars would proceed pretty much as normal.
After babies are born gravity becomes important for further development and animal studies should be carried out at Mars' gravity to determine whether the reduced gravity is truly damaging to infant mammals. Now where did I put that reduced gravity simulating satellite?

#124 Re: Not So Free Chat » Politics » 2019-11-12 11:53:29

A wall in Colorado! Really?

#125 Re: Life support systems » Solar Enclosure Architecture On Mars » 2019-11-12 11:36:46

Better prevent those from freezing. Ice expansion might do a lot of damage to such a design.

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