Moon mission today - Dragon & Mars hab

RobertDyck · 2019-01-04 02:29:28

SpaceNut wrote:

One the note of how much space we will need for a crew going to the moon or mars will be important.

Your chart shows 18 cubic metres per person for a mission of 6 months or more. A Mars Direct habitat will have 8.4 metre outside diameter, approximately 8.0 metre inside diameter. So the upper floor alone will be πR² = 3.14159*(8.0/2)^2 = 50.26548 square metres floor area. Assuming 2 metre ceiling height (6' 6¾"), and divide by 4 crew members, that works out to 25.13274 cubic metres per person. If you use 2.4384 metre ceiling height (8' 0"), then it's 30.641838 cubic metres per person. And again, that's the upper floor alone. The lower floor will be airlock, storage compartment for rover and surface science equipment, stairway, life support equipment, landing rocket engines and propellant tanks, RCS thrusters and their propellant tanks, and landing legs. Once on Mars the storage compartment will be empty, providing usable space EVA prep and laboratory and/or workshop, but during transit to Mars it will be packed full. Once on Mars, the inflatable greenhouse will be deployed, increasing floor area/volume further.

If you want to work that out for 6 crew members, same habitat with 2.4384 metre ceiling, that's 20.42789 cubic metres per person. Again that's upper floor alone.

Last edited by RobertDyck (2019-01-04 02:56:19)

kbd512 · 2019-01-04 04:14:49

Why not make that entire habitat a vehicle with wheels or tracks on the landing struts so there's no need for a rover and the astronauts can simply travel with their habitat and carry spare parts with them in case they break down somewhere?

If you had deployable thin film arrays and batteries that could take you 25km per day, is that enough for exploration purposes?

You need to get out and collect rock and regolith samples for analysis to find all the goodies, right?

That way you take all your personnel, consumables, radiation protection, and scientific equipment with you. Wouldn't that simply things?

Obviously smaller vehicles require less power, but then you need miniaturized version of everything to take with you. This would solve that problem. Everything you have is available at all times. Maybe the habitat could be sectioned in two with a pressure bulkhead so that even a leak in one half would still leave half of the available space. Nothing's perfect, but this seems like a compromise to me.

RobertDyck · 2019-01-04 04:33:01

SpaceNut wrote:

https://ntrs.nasa.gov/archive/nasa/casi … 005557.pdf
LOX/Methane In-Space Propulsion Systems Technology Status ...

Italy - Agenzia Spaziale Italiana (ASI)
Tested MIRA Demonstrator, a 100-kN (10-tonne) thrust class, expander cycle LOx/LCH4 engine, for the a new upper stage of Vega, in cooperation with Roscosmos
Successfully tested at the complete engine level
More than 11 tests performed up to full operating condition
Accumulating more than 600 s of firing.
Development and testing of liquid methane fuel turbo-pump bearings
With JAXA, ASI is investigating the methane thermal behavior, characterizing bearings working in liquid methane, and designing a regenerative thrust chamber in the 100-kN (10-tonne) class which is to be tested in Italy
Designing small methane thrusters to be applied as a potential reaction control system of the launcher stage

This is very encouraging! MIRA has already been tested, it's the right size for a Mars Direct ERV; 4 such engines would be perfect. If it could be throttled, it's the right size for landing engines for the Hab. And they're working on reaction control system (RCS) thrusters, perfect for the Hab for in-space manoeuvring during transit, or for the ERV.

As for storage, Falcon 9 uses 50 psi in the tanks. At that pressure, methane boils at -144.22°C. Shuttle ET used 34.7–36.7 psi; at 36.7 psi methane boils at -149.07°C. At 100 psi methane boils at -131.747°C. And to reduce boiling temperature to -123°C (temperature of the Moon in shade) requires 10.4729 bar = 151.89657264 psi. So a round number: at 150 psi methane boils at -123.27376875°C.

Calculation of thermodynamic state variables of methane

Temperature on the exterior of ISS in shade varies from -100°C to -150°C depending how long it's in shade. So simple a simple sunshade to protect a LCH4 tank in the vacuum of space should produce similar temperatures. Multi-layer insulation on the exterior of a "trunk" or hull, with a separate LCH4 tank inside separated to prevent direct physical contact with the hull, perhaps held by a strut, should keep the tank close to -150°C.

If using rotation for artificial gravity, you may want to expose one end of the stage to space to allow radiation, but that means a sun shade to prevent direct sunlight while it rotates in that direction.

This means a combination of smart design to allow radiation into space for cooling while preventing direct sunlight onto the tank, together with higher tank pressure, would completely prevent boil-off.

kbd512 · 2019-01-04 06:36:38

Robert,

You don't have to go to crazy pressures to prevent boil-off. Centaur's total heating rate was less than 1kW/hr with white paint over stainless steel. The later addition of MLI knocked that down quite a bit. There are diminishing returns with MLI, though. The 20 layer Centaur solution was 100 pounds and the 45 layer solution was 200 pounds. A cryocooler and thin film solar cells affixed to the tank insulation should supply sufficient power to keep the propellant cold indefinitely without getting very creative. If the direct attachment option is impractical, then surely the spacecraft can spare a couple kilowatts of power in cruise to handle heat removal. The cryocoolers on some of our space telescopes and experiments have operated for more than a decade before they began to fail and they were keeping Helium liquid. Methane should be entirely doable with present technology. Surely a spare cryocooler would be useful for some scientific instruments, too.

Edit:

Here's the source document for Centaur heating rates:

Centaur Upperstage Applicability for Several-Day Mission Durations with Minor Insulation Modifications

Edit #2:

Solar Electric Centaur-based orbital transfer vehicle using arc-jet thrusters:

CENTAUR-DERIVED PROPELLANT SUPPLY SYSTEM FORA SOLAR ELECTRICORBIT TRANSFER VEHICLE

Last edited by kbd512 (2019-01-04 06:44:12)

SpaceNut · 2019-01-04 19:32:27

Kbd512 we have a topic that was geared at mars for RV'ing around ist surface as well as a nuclear powered rover for the same but its shield mass was an issue but on the moon the level of solar is plenty to make a solar vehicle possible.
Nasa was looking a the chariot truck to place the hab we came down in sort of a tin can on wheels.

Centaur stage scaled for the lunar mission would work just fine and we still need to drop mass so as to make the fuel mass drop as well. Using expendables for the habitat and other heavy cargo is the way I would go leaving the lander for the crew just as small as we can as we will not be staying in it.

If I recall the landing margin could be used to make water and energy if we have a fuel cell as we can later make methane as we can use it to break water back down.

Mars_B4_Moon · 2022-07-04 05:36:27

NASA still can not do a Moon mission today, however it is much closer to doing so

This Week at NASA Launching a New Mission Around the Moon
https://scitechdaily.com/this-week-nasa … -the-moon/

Northrop Grumman’s Cygnus Spacecraft Successfully Reboosts the International Space Station
https://news.northropgrumman.com/news/r … ce-station

SpaceNut · 2022-07-04 13:34:10

ya the cygnus could be converted into a very good habitat but there is no Dragon capsule to go with it unless you have deep pockets to fund your own mission.

Mars_B4_Moon · 2022-09-14 05:17:47

Artemis SLS rocket has taken years longer to develop than the Apollo moon program
https://www.cbc.ca/radio/quirks/artemis … -1.6577261

China plans 3 moon missions to investigate a potential new source of energy
https://interestingengineering.com/inno … rgy-source

Mars_B4_Moon · 2023-09-16 18:32:18

Caves and Tunnels?

Absolutely LOVE looking at new impacts on planetary bodies.
This one is on the Moon, as seen by the LROC-NAC instrument, and happened in 2012.
https://twitter.com/Peter_Grindrod/stat … 2097115229
The new crater is about 70 m across, and would definitely hurt.

Mars_B4_Moon · 2023-10-07 06:51:18

Italy

lunar regolith oxygen extractor mission

https://europeanspaceflight.com/asi-to- … r-mission/

Mars_B4_Moon · 2024-03-02 06:00:13

SpaceX could fly Starship as many as nine times this year
https://interestingengineering.com/inno … -this-year

Viking missions were launched riding atop Titan IIIE rockets with Centaur upper stages. The recent missions to Mars have show some successful feats although Europe has still to yet have a working lander, NASA JPL have many successful feats, India is at Mars, China had a working Rover which eventually got killed by 'Mars Dust' and Orbiter, Japan launched a mission for an islamism semi-constitutional monarchy United Arab Emirates, NASA's Psyche will fly by en route to an Asteroid. NASA JPL have the Nuclear powered Perseverance (rover) based on success of the beaten up looking Curiosity rover , there have been helicopter flights until Ingenuity stopped operations, there was an ExoMars Trace Gas Orbiter by ESA/Roscosmos this type of mission is unlikely to happen because of sanctions on Russia after the invasion of Ukraine, Arianespace has said that the first Ariane-6 launch attempt will not occur until 2024, in fact Europe kind of looks to be in trouble, Ariane-5 for its time was modern but these rocket familes might now be dinosaurs due to innovation new ideas from Commercial sector and new rockets from the Private Sector.

although recent missions show the Moon has not been easy

Post-Shuttle era and post-USSR there seems to be a loss of knowledge of landing stuff on the Moon and getting the Rovers or landers to function like was done in past feats during the 'space race'.

Russia's Luna-25 ended in failure

Intuitive Machines holds NASA contracts under the space agency's Commercial Lunar Payload Services (CLPS) initiative, Odysseus lander fell on its side when landing, its instruments remained partially functional, it was somewhat sucessful

There does not seem to be a topic dedicated to 'SLIM' from Japan. Smart Lander for Investigating Moon (SLIM) is a lunar lander mission of the Japan Aerospace Exploration Agency

The MBC started as expected, but unfortunately did not function properly. This is likely due to the nighttime conditions, but we will prepare for another opportunity based on the obtained data. We received so much support for our operations after the lunar night: thank you!
https://twitter.com/slim_jaxa/status/17 … 4765261980

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#151 2019-01-04 02:29:28

Re: Moon mission today - Dragon & Mars hab

#152 2019-01-04 04:14:49

Re: Moon mission today - Dragon & Mars hab

#153 2019-01-04 04:33:01

Re: Moon mission today - Dragon & Mars hab

#154 2019-01-04 06:36:38

Re: Moon mission today - Dragon & Mars hab

#155 2019-01-04 19:32:27

Re: Moon mission today - Dragon & Mars hab

#156 2022-07-04 05:36:27

Re: Moon mission today - Dragon & Mars hab

#157 2022-07-04 13:34:10

Re: Moon mission today - Dragon & Mars hab

#158 2022-09-14 05:17:47

Re: Moon mission today - Dragon & Mars hab

#159 2023-09-16 18:32:18

Re: Moon mission today - Dragon & Mars hab

#160 2023-10-07 06:51:18

Re: Moon mission today - Dragon & Mars hab

#161 2024-03-02 06:00:13

Re: Moon mission today - Dragon & Mars hab

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