New Mars Forums

tahanson43206,

Why are photovoltaics and wind turbines not being used to build more photovoltaics and wind turbines here on Earth?

Hazard a guess as to why you think that is.

For the 500 colonist ship, I'm allocating the following masses:

350t - ship's hull
50t - ship's complement
155t - food for 180 days
100t - water reserves
45t - furnishings, clothing, toiletries, and misc consumables

Mangalloy is 7,800kg/m^3, which only provides 44.872m^3 of hull material to work with
Sylramic fiber C/SiC Ceramic Matrix Composite is 3,210kg/m^3, providing 109.034m^3 of hull material

Both materials provide comparable tensile strengths in finished form.  CMCs are stiffer than steel, so less deformation under load.  The CMC would not lose much strength in the event of a fire aboard ship, as Sylramic fiber was intended to out-perform Nickel-based superalloys.  The proposed Mangalloy cannot operate above 260C without losing its ductility over time.

Using CMCs for primary structure would necessitate sealants between the individual "donuts" / "wedges" comprising the toroidal habitation ring structures.  This implies use of air-tight gaskets between sections, so perhaps thin stainless steel gas-tight crush seals can be fabricated since these work pretty well in high pressure applications, such as air conditioning systems.  Multiple sections would be bolted together and uniformly "crush down" on the sealing gaskets.  Silicone seals could also be used, which are standard for US Navy ships, but nowhere near as heat resistant as multi-layer metal gaskets.  CMCs may not benefit as much as metals do from ceramic thermal barrier coatings to protect the material from corrosion damage or weakening due to fire, and thermal expansion is markedly lower than it is for metals, but C/SiC's thermal transfer coefficient is or can be at least 2X higher than Mangalloy, so additional thermal insulation is required.  The cost issue at play is that for near-zero porosity, as achieved by CMC components like gas turbine blades or hot section casings, some kind of vapor infiltration processing method is required to fully densify the ceramic matrix around the fiber reinforcement, and that process is expensive.

The net benefits of CMCs of the variety considered here are equal strength to austenitic steels (on par or stronger than Mangalloy and meaningfully stronger than stainless), comparable or greater stiffness, much lower CTE, much greater temperature tolerance range from deeply cryogenic to 1,200C, thermal shock resistance, much greater achievable section thicknesses for a given weight, and the potential to either reduce weight or add strength to critical areas.  There would be no on-orbit fixturing and welding of the hull structure, merely bolting it together.  That would greatly reduce the complexity and cost associated with assembly.  We have extensive experience with on-orbit assembly, but very little with on-orbit fabrication.  There would be no post-fabrication grinding / machining of the CMCs, either, because they're created using high precision molds.  Metal expands and contracts quite a bit after sintering or casting, which implies cleanup machining of some very large individual parts, though not terribly heavy.

There would be a modest radiation dose reduction over steels, but ceramics are still oxidized or nitrided metals at the end of the day, albeit thicker and combined with Oxygen or Nitrogen which promotes more elastic collisions to help absorb ionizing radiation, very strong microwave radiation absorption, decent X-ray radiation absorption.  It won't do much of anything against gamma rays or heavy relativistic ions, but neither will thinner sections of steel, which will promote showering of the crew with secondaries.  The interior and exterior BNNT fabric overwraps will do a much better job against secondary radiation, but are still basically sheets of typing paper being pitted against armor piercing bullets.  Only a large volume of water or other Hydrogen-rich materials have much chance against GCRs.  For a 6 month trip, apart from shielding against solar flares and CMEs, I think the rest of the radiation dose has to be "taken on the chin" until active systems are devised to protect ships.

300t of reserve mass will be allocated to:
ship's amenities such as the cafeteria, food cooking and storage, toilets, showers, etc
interior airtight bulkheads and hatches
interior thermal protection fabrics
exterior hull ballistic and thermal protection fabrics
sCO2 gas turbine RTG electrical power supplies
LCO2 storage for RTGs and shipboard firefighting
thin film photovoltaics for supplemental electrical power
radiator arrays for thermal regulation
electrical wiring and air ducts for interior air circulation
docking hatches, fittings and electric motors for counter-rotation
PEMFC main propulsion system power supply
H2O propellant ion engines
compressed H2 / O2 storage tanks to power the main propulsion fuel cell
supplemental water propellant storage tanks

Total dry mass target, less propellant, is 1,000t.
Total wet mass target is 1,500t to 1,700t.

tahanson43206,

Air and Earth styles should work now.

tahanson43206,

My final thoughts on Void's proposal is that if the required changes prove to be relatively minor, then it could be a faster / cheaper pathway towards initial human Mars exploration missions.  By its very nature, it will never be a like-kind substitute for a purpose-built highly compartmentalized ship intended for transporting hundreds of colonists vs a dozen astronauts.

I would place Void's proposal in its own AG-enabled Large Ship Prototype category.  It could be used to prove the feasibility of AG and counter-rotation, evaluate the effectiveness of the various protection schemes afforded to a large interplanetary transport ship, and function as a testbed for the life support / power / propulsion systems, as well as the first operational use of an interplanetary transport ship worthy of that title.

High-Manganese steel is an acceptable substitute for 316L stainless when the atmosphere of the interior of the ship, and thus the metal hull, will be kept relatively warm.

Weldable 316L austenitic stainless yields at 25ksi.  Non-weldable 316 stainless yields at 30ksi.

Weldable austenitic Mangalloy yields between 50ksi to 75ksi.

At least doubling both yield strength and hardness over 316, as well as substantially increased abrasion resistance if objects ever impact the interior of the hull by accident, is very important.  At room temperatures, Mangalloy steels will have ductility comparable to austenitic stainless steels, but at a minor fraction of the cost.  316 will have better ductility at deeply cryogenic temperatures, but I don't think a crewed vehicle with a cryogenically cold hull is compatible with human survival.  Thermal conduction, in conjunction with a multi-layered insulation and ballistic protection overwrap applied to the hull's exterior, should ensure that no part of the hull is subjected to the greatest extremes of hot or cold.

This is a very lengthy but very expressive missive on all aspects of high-Managanese steel production and fabrication processes, with comparisons made with austenitic stainless steels as well as other kinds of steels and some insight as to why to choose one over the other:
Austenitic Manganese Steel

I would fabricate the hull from Mangalloy, with a keen eye towards the weldability of the alloy without cracking or stress concentration, then I would coat the entire hull, inside and out, with a plasma spray deposited ceramic coating to resist corrosion damage, and then I would apply a CNT fabric overwrap that provides both ballistic protection and acts as a "heat spreader" to maintain temperature uniformity over the entire hull.  Very large rolls of CNT fabric "matting", similar to unidirectional Carbon Fiber tapes, are now available.  On the interior, I would apply BNNT fabric to the hull, to absorb secondary radiation, act as a thermal blanket, and prevent an interior fire from weakening the steel or otherwise threatening the airtight integrity of the hull.

To keep weight reasonable, we're talking about using rather thin pieces of sheet steel, hence the use of a stronger base metal and the elaborate protection scheme afforded to the ship's crew and passengers.

Wiring for shipboard electrical systems would consist of CNT conductors with BNNT fabric insulators (not plastic).  This will drastically reduce weight over shielded Copper conductors and plastic insulation, by about 80%, increase the resistance of the wiring strands to cutting or abrasion, provide extreme resistance to fire, and reduce the possibility of a fire generating toxic smoke in the cabin air supply.  The electrical connectors will use BNNT-reinforced sintered ceramics for fire resistance and weight reduction.  Here again, the elaborate protection scheme is centered around preventing fires, fire resistance, and general durability.  The reduction in interior metal content is also driven by a desire to limit secondary radiation emission associated with high energy particles (galactic cosmic rays) striking the hull.

I think the most economic way to produce the ship's hull will be using a series of precision castings that have been ground to final size.  The reason for this has to do with achieving near-perfect balance of all parts of the rotating assemblies.

Whereas modern gas turbine blades are hollow to circulate cooling air through the internal channels depicted above, we require an active stabilization system that keeps the rotating components balanced as weight shifts around inside the ship.  Apart from preventing unwanted changes to the ship's trajectory, the primary reason for doing this is preventing uneven wear on bearings or distribution of force on highly loaded thin-walled components.

This vessel is an aerospace vehicle, not an ocean-going ship in the conventional sense.  Weight matters quite a lot, as does the quality of the materials used and workmanship.  We need to be very deliberate about how we go about approaching its design, not fixating on any single aspect of the vehicle to the detriment of all others, and we must remain pragmatic about what the vehicle is optimized to do.

After reviewing state-of-the-art PEMFC and ion engine technology, with PEMFCs fast approaching 40kW/kg, I no longer think we need nuclear propulsion.  This moves the large ship concept solidly into the realm of feasibility, because there are now water propellant ion engines generating sufficient thrust and Isp.  We still need about 500MWe, meaning a 12,500kg fuel cell, but we're going to use a novel application of the steam being generated by the fuel cell.  We're going to push the fuel byproduct (steam) required to power the fuel cell, through the ion engines.  To my knowledge, this has never been done before, but we're going to do it, because we need to repurpose that which powers the fuel cell to also supply reaction mass to the ion engines.

We may still require nuclear power to provide sufficient life support electrical power for 500 colonists, but that which powers the propulsion energy generating system and the propellant itself can now be the same materials.  Rather than using cryogens, we now have high pressure CFRP storage tanks that can store sufficient Oxygen and Hydrogen.  From my reading of the literature on Mangalloy steel, special formulations of that material do not appear to suffer from Hydrogen permeation and embrittlement to nearly the same degree as other metals such as stainless steel, which means we can use steel liners for the Hydrogen storage tanks.  Oxygen presents a real challenge for Mangalloy, which means the CFRP Oxygen tanks will require stainless liners or Mangalloy with an appropriate coating.  We may still use cryogens and light metal tanks for achieving escape velocity from Earth, but the return trip will rely upon a lesser volume of highly compressed gas.

The greater use we make of non-nuclear COTS technology, the greater our chances of convincing an organization such as SpaceX to build purpose-built interplanetary transport ships and landers, keeping those valuable Starships here at Earth, for economic delivery of payloads to LEO.  We may be able to achieve better results using nuclear technologies, but the licensing and economic hurdles to implementation are extreme.  We will certainly need fission surface power systems for colonization, so perhaps that's where political and monetary capital should be expended to bring this dream to fruition.

tahanson43206,

After I log in, I still see the stylesheets applied to all the web pages.  I poked around through a lot of the different pages and menu options.

1bbl of crude = 139.3kg
Carbon = 127.6kg (468kg CO2)
Hydrogen = 11.6kg
1kg CO2 (direct ocean capture) = 1.8kWh
1kg H2 (water electrolysis) = 50kWh

CO2 = 842.4kWh/bbl
H2 = 580kWh/bbl
Sabatier reaction = 4,637.3kWh/139.3kg

Input Insolation = 6.85kWh/m^2/day (in a Midwest desert)
Polished Aluminum Mirror = 6.165kWh/m^2/day

6,059.7kWh / 6.165Wh/m^2/day = 983m^2 of solar thermal collector area per bbl per day
20,246,575bbl/day * 983m^2/bbl/day = 19,902,383,225m^2 = 19,903km^2 (141km by 141km)

2mm x 1m x 1m = 34.5394lbs/m^2 of rolled / stamped steel (hot-dipped in Aluminum, then polished)

19,902,383,225m^2 * 34.5394lbs/m^2 = 687,416,375,162lbs / 311,807,194t

$880/t * 311,807,194t = $274,390,330,720

Let’s double that figure to $550B to account for the steel support structure for the solar thermal mirrors.
Crude currently sells for about $67/bbl.

$67/bbl * 7,390,000,000bbl/year = $495B

Let’s double the cost again to account for fabrication and installation labor.  We’re sitting at around $1T.

Over 20 years, we’re spending around $50B/year to supply our hydrocarbon energy input requirements for the next century.

3.11Bt of steel produces sufficient energy input for global supply of petroleum of petroleum base product (Methane).  We produce about 1.85Bt of steel per year, so the materials input to supply the petroleum base product for at least the next human lifetime is equivalent to 2 years of steel production.  We'll have to add more equipment and energy to go from Methane to gasoline or diesel, but after you produce the Methane, the input energy requirements to go from Methane to gasoline are not nearly so high.

Almost anyone with a pocket calculator could quickly and easily figure out that not running out of energy is dramatically more important than the paltry amount of money and steel required to ensure that never happens.  It's nuts (to me) that an oil company hasn't already determined that making sure the profits never stop rolling in is the absolute best reason to recycle CO2.  If there are energy surpluses to be had, then we make sure we capture extra CO2 and convert that to solid Carbon ("coal") using Gallium.

No tire company functions without Carbon Black.  No coal-fired power plant functions without coal.  No Carbon Fiber company functions without Carbon.  None of our advanced manufacturing tech, or not-so-advanced tech, functions at all without on-demand energy.  That is a fact, no matter how much we attempt to ignore reality.

An actual synthetic petroleum production facility is at least guaranteed to produce the goods.  Another oil well may or may not, and it won't produce for very long since we've already consumed the easy-to-get oil.

It seems as if we need some long-term thinking here.

I think that SSTO I proposed would make a fantastic upper stage for the Super Heavy booster.  It generates lift, so it has cross-range and can land on a runway.  The pressurized passenger compartment could be used to return ZBLAN fiber optic cable from orbit, back to Earth, with a lower probability of loss than a vertically landed upper stage.  The fiber optic cable cargo would be much easier to offload than it would be from Starship, and the crew could oversee the loading and unloading of the cargo.  The upper stage could then be flown back to the launch pad using a conventional jet engine, for which there's plenty of mass margin since it doesn't need to achieve orbit all on its own.  The booster provides enough of a Delta-V reduction that the vehicle could achieve high orbit to drop off passengers, come back down to a lower orbital altitude to pick up ZBLAN from the manufacturing plant, and then return to Earth, and to choose where to land to offload the cargo.  It could go to Silicon Valley, Japan, South Korea, or anywhere else that a paying customer wants the latest and greatest fiber optics tech for their networks, which would probably be anywhere with a runway capable of landing an airliner.

Passengers could go up to an awaiting interplanetary transport for the lucky few who get selected to venture out to our colonies, the vehicle reduces its orbital altitude to stop by an orbital manufacturing facility to pick up fiber optics or photonics "chips" or similarly valuable products, and then the high value cargo and any returning passengers reenter and fly to an airport of convenience (for delivery of the cargo) here on Earth.  The passengers then fly back to the states or wherever they're originally from, aboard a commercial airliner.  There are revenue generating payloads going both ways, so the ticket price to go to another planet could be reduced since some of the generated revenue comes from the passengers and the rest comes from high-cost / high-demand electronics and telecommunications products that we'd very much like to use to replace existing Copper or lesser quality fiber optics here on Earth, but unfortunately the ZBLAN crystals grown on Earth look like crap, whereas ones grown in orbit look flawless.

This would be the first practical application of space, used to simultaneously unlock interplanetary transport and orbital manufacturing of next generation computers and communications equipment.  The photonics-based computing and sensor tech would dramatically reduce the energy consumption associated with data center computing and AI, which is now eating more energy than the entire global air travel industry.  Low cost fully reusable rockets are akin to a "cheat code" to level-up our tech and travel capabilities.  There's an implicit defense application for Space Force as well.  If we can use some of the interplanetary transport tech to go after the metals in the main belt, then we get functionally unlimited Platinum group metal catalysts for advanced energy tech, CO2 removal, and various other technological "goodies".  Beyond that, we need to find new sources of Copper and Silver, or this idea of electrifying everything will remain a dream forever.

Our newly formed "Department of Government Efficiency" should appreciate the "How many different birds can we kill with the same stone?" aspect of this as well.  We have lots of people with degrees, and we just imported millions of people with hand labor skills but no degrees.  Unfortunately for both groups, there are few jobs worth doing because they don't ultimately take us anywhere new.  Solving these engineering-based problems, none of which are beyond our technical capabilities so they need not devolve into endless pointless science experiments, would be well worth the time and labor devoted to it.

I think WWIII is already in-progress, even if it remains undeclared, but this "unlock space" project would become the "silver lining" following the hell on Earth that we're about to be subjected to.  Our children can look forward to this on the other side of the war- something which puts those of us who remain onto a project that is broadly beneficial to humanity, and provides a huge surge in demand for people, ideas, materials, and technologies.  The Greatest Generation had the opportunity to "remake the world" following WWII.  Our children will get the same opportunity.  Everything involving humanity operates over cycles.  Along the way, we somehow manage to progress a bit.

Calliban,

I'm going off of reporting from various left and right foreign and domestic media reports that they're not going to certify election results until the end of this week, but that the Republicans have now gained the votes to secure 219 seats and the Democrats gained or likely will gain the votes required to secure 213 seats.  By current vote tally, Republicans have 219 seats and Democrats have 210 seats.  The 3 seat discrepancy is expected to go to the Democrat candidates.

If that changes between now and the end of the week, I'll add an update.  The remaining races are either too close to call or contested by the candidates because the results are close enough to request recounts.  That means there will be a handful of races which require recounts, but 432 of 435 seats appear to be accounted for at the time I wrote my last post.  If nothing unusual happens between now and then, the most probable makeup of the House of Congress going into 2025, will include 219 Republicans and 213 Democrats.

"270toWin" reports the results before they're certified.  The Associated Press remains the official reporter of election results, but again, they typically only report results after results are certified.  Based purely on counted votes and majorities, the 219 Republicans and 213 Democrats appears to be the most probable outcome.

I think this headline speaks for itself:

CNN Politics - FEMA employee fired after telling relief team to skip houses with Trump signs following Florida hurricane

These political clowns actually wrote in their official government records, "Trump sign, no entry per leadership.  Implement best practices, avoid homes advertising Trump."

FEMA states that this incident in Florida is believed to be an isolated incident, but weaponization of politics aptly explains why FEMA and local officials did not help residents living in Appalachia in the wake of Hurricane Helene, and actively prevented private citizens from other parts of the country from bringing in disaster relief supplies (food, bottled water, and blankets) using personal helicopters and high water pickup trucks, as well as threatening these volunteers with arrest if they continued helping those living there.  Thankfully, some of these civilian first responders ignored the government's threats to arrest them and continued bringing in supplies.

I would opine that perhaps "FEMA" ("Federal Emergency Management Agency") should change it's name to "DEMA" ("Democrat Emergency Management Agency") if those working within FEMA only wish to provide disaster relief to Democrats, and that funding "DEMA" be considered optional for all Republicans.  Maybe Elon Musk's new Government Efficiency Agency can cut FEMA's funding to only whatever is required to serve Democrats.  Assuming Democrats don't attempt to arrest civilians providing disaster relief, Republicans can rely upon private citizens with religious core values (love for your fellow citizens, willingness to serve and to sacrifice for others, and the ability to look past political beliefs) to provide disaster relief whilst Democrats are free to spend money on other Democrats, or not, however they see fit.

This is exactly what I meant when I admonished Democrats to "stop pouring acid on the fabric of society".  There can be no trust between government and the citizenry if those in government are using the power of government as a cudgel against their political opponents.  Either tell your fellow Democrats to cut this crap out, or expect big changes to government in the near future.  If half of the people in government only want government to serve those aligned with their partisan politics, then that is what government will become.  At that point, you will no longer have the consent of the governed, for at least half the population.  Since all legitimate forms of government are derived from the consent of the governed, we will rapidly cease to have a functioning government.

President-elect Trump should focus exclusively on:

1. Fixing the American economic issues related to energy extraction and domestic manufacturing
2. Border control and illegal immigration issue allowing violent criminals to enter America and prey upon Americans and other illegals
3. Foreign wars and antagonistic relationships with our adversaries, namely China, Russia, and Iran

As someone who actually voted for President-elect Trump, I listened intently when he promised to do those three things and nothing else, in his victory speech.  I expect him to remain faithful to his word, or he no longer has my support.  The Republican Party only has the most tenuous of support from me, presuming they work with President-elect Trump to deliver on his promises.  If the man I voted for does those things and nothing else, then his presidency will be a breath of fresh air when compared to the petty self-serving behavior of President Biden's administration.

I am completely onboard with America focusing on fixing our own numerous and varied domestic problems, which have strained ordinary Americans to the breaking point.  Specifically, I want domestic energy and manufacturing output to increase to increase wages, and to help pay down our absurd level of national debt.

I am completely onboard with America refraining from all forms of military adventurism.  I want a strong military with thorough realistic training, appropriate tools, and no attempt to "gold plate" our military equipment or capabilities.  I do not want our military used to preemptively attack other nations, even if I vehemently disagree with what they're doing.  I do not want our intelligence agencies instigating foreign wars.  I do not want our military used to support the foreign economic interests of businesses.  America should never go to war because some yahoos in an intelligence agency are having a "war fantasy" or XYZ Corporation stands to make a handsome profit from that war.

I am NOT onboard with any ill-advised attempts at "revenge" against political opponents, as the Democrats have engaged in since President Trump was elected in 2016.

I am NOT onboard with indiscriminately bombing the piss out of Palestinian civilians who have guns pointed at them from both Hamas or Hezbollah or Iranian terrorists and Israeli troops.  I DO support Israel's right to exist, right to defend their borders, and right to kill all murdering invaders.

I am NOT onboard with spending endless money on killing Russians.  I DO support Ukraine's right to exist, right to defend their borders, and right to kill all murdering invaders.  I would like them to focus on driving the Russians out of Ukraine, rather than attacking and invading Russia.  President Zelensky has said he wants all territory taken from Ukraine, returned to Ukraine.  Great.  I agree with that 100%, so I would like him to focus on doing that.  Invading Russia is not helping to drive the Russians out of Ukraine.  It is weakening Ukraine's ability to fight against Russian troops inside Ukraine, because that's how basic math and logic works.

As allies, if Israel or Ukraine or Taiwan or South Korea need to be defended against foreign aggressors, then we send our own military, our own sons and daughters, to fight on their behalf.  We articulate why it's necessary to do so to the American people.  We commit ourselves to doing only that which is necessary and justifiable.  That is what a true ally would do to support their allies.  If our allies no longer wish to have American troops on their soil, or refuse to spend agreed upon money for their own defense, then we leave.  We don't dictate policy to them, but we both honor the terms of our agreements, or we're no longer behaving as good allies.

Finally, I want American citizens prioritized over immigrants, especially illegal immigrants.  All the foreign criminals allowed to pour into America because the officials from President Biden's administration, specifically Secretary Mayorkas, couldn't be bothered to check IDs at the border, is completely unforgivable.  Democrats seem to think any immigration laws they disagree with are mere suggestions, rather than codified law.  Congress doesn't make suggestions.  Congress makes law.  The majority of Americans disagree with the Democrats on this point.  We would prefer that our elected officials and their political appointees either enforce our laws or work with Congress to change the laws if they think our existing immigration laws are unfair or unenforceable.  Maybe our immigration laws could be better, but since we've never made any serious attempts to improve them, we don't actually know, because we haven't tried.

US 2024 Elections Results Updates

House Elections Results
Republicans secured 211 seats.
Democrats secured 199 seats.