* Posts by IT Poser

203 publicly visible posts • joined 16 Mar 2016


What will life in orbit look like after the ISS? NASA hands out new space station contracts

IT Poser

Re: In this day and age no centrifugal section?

I agree that artificial gravity is something we should figure out before we undertake multiyear journeys. That is why my Ceres plans start with building a shipyard in LEO that builds a series of rotational gravity prototypes. Assuming I had an infinite supply of money the science and engineering needed for spaceships with artificial gravity could be done in as little as a decade.

The reality is no one who could conceivably afford to do so is currently planning on funding multiyear journeys. The closest is Musk's Mars plans, but the journey to Mars should take three to six months. The typical ISS mission last six months so we know it is possible to keep humans relatively healthy without needing to spend the time and money to develop artificial gravity ships for Mars.

IT Poser

Re: In this day and age no centrifugal section?

SpaceX's proposal didn't include a centrifugal section.


The real question is who is going to pay for a centrifugal section and why?

NASA wants the companies developing ISS replacements to fund at least 60% of development themselves. These companies aren't going to be doing this out of the goodness of their hearts. They are going to be looking to recoup their costs by leasing station space to non-NASA customers. Therefore we want to look at potential customers and figure out what they want and need.

Research done on ISS indicates there is a comparative advantage for manufacturing some products in microgravity. Drawing high quality fiber optic cable or growing replacement organs appear they will be highly profitable activities once the bugs are worked out of the production processes. In the case of drawing fiber optic cable vibrations from the centrifugal section are harmful to product quality so the companies attempting to bring this to market won't want a centrifugal section attached to their production facility. Manufacturers whose processes depend on gravity can get that for free here on Earth so we can't look to manufacturing to recoup the costs of developing a centrifugal section.

Another potential customer base is tourists. My informal survey suggests most tourists definitely want the chance to join the zero G club so a microgravity section is a must. Experiencing artificial gravity is something few are interested in. Having toilets and showers that function like those here on Earth would be nice but the costs would need to be tightly controlled. Developing and building a 100+ meter diameter centrifugal section isn't going to be cheap. Perhaps there might one day be enough demand to recoup the costs. For now all there is is speculation that does not justify the business case.

Boeing's Calamity Capsule might take to space once again ... in the first half of 2022

IT Poser

Re: Pro Tip - -> WD40

WD40 plus N2O4 equals <see icon>

NASA signs $1bn deal with Northrop Grumman to build studio apartment in lunar orbit with room for 3 vehicles

IT Poser

Why use NRHO(Near Rectilinear Halo Orbit) is because Orion only has ~1350 m/s of available Δv(change in velocity). Entering and exiting LLO(Low Lunar Orbit) on a direct trajectory(like how Apollo did it) requires at least 700 m/s each way. Entering and exiting NRHO requires ~450 m/s each way so NRHO is within Orion's operational range.

Orion does indeed "hitch a ride" down to LLO altitude but Δv of ~750 m/s needs to be applied to transfer from one orbit to the other. The plan is for the lander to provide the additional Δv for the orbit change. From LLO an additional ~2000 m/s is needed to reach the Lunar surface.

When we consider both Orion and lander propellant(fuel and oxidizer) going to the Moon via NRHO requires at least 33% more. At least is because lander propellant requirements depend on lander design. This is not ideal but since Orion isn't capable of operating in LLO and Congress mandates NASA must build SLS/Orion.

Since you mentioned time I'll briefly touch on the topic. Orion going to or from NRHO and Earth takes ~6 days versus the ~4 days needed if Orion could go to and from LLO. The lander going to or from NRHO and the Moon requires 12+ hours versus the 30 minutes or less for LLO. Minimum layover time on Gateway is ~7 day versus the 2 hours for LLO.

IT Poser

Re: What actually is "a near-rectilinear orbit "?

Here is a link to a useful vizualization.


And a link that delves into the mathematics of rocket science.


NASA doubles down on Venus missions, asking what made the planet uninhabitable

IT Poser

Re: unless you can invent things that will run at 460 centigrade ambient

Sorry for the delayed response. Life happened.

SiC MOSFETS and diodes are being manufactured. Connect these components properly and we get a processor. Granted this will be primitive compared to an 8086 but developing new technology takes time. Then again Apollo Lunar Module computers were primitive compared to early PCs.

Venus' thick atmosphere pairs well with wind turbines.

IT Poser

Re: unless you can invent things that will run at 460 centigrade ambient

Luckily brilliant boffins already invented silcon carbide (SiC) semiconductors:


And for those who claim money spent on space exploration is money wasted instead of doing something to make things better here on Earth:


Not so fast, SpaceX: $3bn NASA Moon landing contract blocked by rivals' gripes

IT Poser

Re: I think it's more about NASA changing the rules of the bid

The Cliff's Notes version is NASA was choosing up to two providers for a 2024 landing. Changing the rules would have been changing the 2024 target date. Therefore NASA had to choose zero, one, or two providers that fit within the projected total budget through 2024 of ~$3 bn. Price was the least important of the three categories the providers were scored on but if there wasn't enough money for an proposal there wasn't enough money. As long as SpaceX scored at least acceptable on managerial and technical metrics SpaceX was the only viable option.

SpaceX was the only provider that received outstanding on the managerial metric. Since Blue and Dynetics were also the lessor options on the second most important they need a win on technical merit to have any leg to stand on.

Unfortunately for Blue and Dynetics SpaceX was also the best when it comes to technical merit. I could was words describing everything but I have a link to a color coded chart. SpaceX is mostly green while the other two are mostly red.


I expect the GAO will dismiss both protests. It's not over for Blue and Dynetics though. NASA has already laid the groundwork to onramp new providers in the services program LETS(Lunar Exploration Transportation Services). This program is structured similar to commercial crew in that it can provide development funds for new landers. Blue and Dynetics need to get to work lobbying Congress for more money if they want this second chance.

A lot of things will have changed with Biden as US president, but an easier ride for Huawei is not one of them

IT Poser

Re: Anyway anyone know any launch codes?


SpaceX small print on Starlink insists no Earth government has authority or sovereignty over Martian activities

IT Poser

Re: there are very few stable low lunar orbits

That depends on your definition of low. At 100 km you are correct sir. The effects of Lunar mascons (short for mass concentrations) distort orbits in this region. As altitude increases mascon effects decrease rapidly. Above 400 km the effects become insignificant.

Also, did you hear the one about the restaurant on the Moon? The food is great but it has no atmosphere.

Drag won't be an issue the hypothetical Moonlink constellation has to deal with. This means propellant isn't needed to maintain orbit like Starlink needs. Dead satellites will need to be actively removed from orbit though.

Google's Alphabet sticks a pin in its Loon internet broadband service

IT Poser

High altitude balloons are great for launching paper airplanes into space.

Trying to launch an ISP is just plain Loony.

Engineers blame 'intentionally conservative' test parameters for premature end to Space Launch System hotfire

IT Poser

Re: Two thirds possible payload is only good when your payload can be made that light

Sorry for the delayed response. There is too much politics on the left side of the pond.

Agreed, but recall Red Dragon. TMI(Trans Mars Injection) is 4.3 km/s while TLI(Trans Lunar Injection) is only 3.2 km/s. This means we know Falcon Heavy can send Dragon through TLI. Thicken Dragon's heat shield, upgrade the comms system, and Dragon could replace Orion for crew transfer. We don't have any other massive payloads because Congress never funded any so you've raised a moot point.

IT Poser

Re: These burn H2 and LOX - the recipe for the best in-vacuum performance.

Which is why hydrolox is used in upper stages. There are trade offs though. Hydrolox requires much larger tanks increasing dry mass. Boil off is much harder to manage. Hydrogen is far more likely to leak. If the stage is reusable hydrogen embrittlement becomes a significant concern. These other factors mean hydrolox doesn't necessarily have the best performance despite having the highest Isp(Well for chemical rockets. Electric propulsion is far better). To be sure we have to work the trades.

The problem with your argument is we are talking about a first stage. First stages need high thrust much more than higher fuel economy. Hydrogen's low energy density is a huge penalty here which is why the SRBs are required. Consider that without the SRBs SLS would have less thrust than Falcon 9 and it makes sense why we would want to use hydrocarbon fueled first stages.

As to, "But AFAIK they won't be able to achieve as high interplanetary velocities as the SLS." that's only true if you ignore refueling. SLS doesn't have this capability so assuming Starship works as advertised Starship will allow much higher interplanetary velocities.

With all that said what really matters is cost. SLS launch cost estimates are now exceeding $2 billion. Falcon Heavy(FH) fully expended has a list price of $150 million. FH can send roughly two thirds as much payload through TLI so a Moon program based on FH would be able to send about nine times as much mass per tax dollar compared to SLS. Starship should be even better.

SLS is good for distributing pork though.

Trump's Make Space Great Again video pulled after former 'naut says: Nope

IT Poser

Re: why the owners of Star Trek haven't sued yet

Because the TOS insignia is strikingly similar to the delta-esque shape in NASA's 1959 "meatball" logo and astronaut pins NASA began awarding in 1963. If you're thinking about the TNG logo that is derived from the Air Force Space Command's logo dating to 1982. The existing government-created prior art makes the suit virtually impossible to win.

After a weekend of WTF-ing at Trump's COVID-19 testing website vow, Google-Verily's site finally comes to life... And it's not what was promised

IT Poser

Perhaps the clean air and lack of fresh CO2 is making me delusional but...

I can't stop laughing at the click to enlarge button below the flowchart. Sure, the stores are out of TP. Sports are cancelled. People are hoarding milk and eggs for some reason. The bars and liquor stores are all closed so the rum is literally gone*. At least I can still count on ElReg to ensure I don't miss a single detail in that perfect description of America's bigly winning virus response.

* Never you mind the bottle in each of my hands.

Tinfoil hat brigade switches brand allegiance to bog paper

IT Poser
Black Helicopters

Re: Aluminium foil isn't a very good shielding material anyway,

As any fule kno you have to use actual tinfoil made out of tin.

Axiom signs up with SpaceX to fly private astronauts to the International Space Station

IT Poser

Bigelow is still around. They merely didn't win access to the ISS port. My guess is Bigelow will be launching the B330 that was being reserved for ISS to a more useful inclination, hopefully before the year is out. Robert Bigelow has said he was launching with or without NASA for over a decade now. I'll take him at his word since I know Bigelow dropped the cash the reserve a 2020 Atlas V launch to take the first B330 to orbit.

FYI the reason the ISS port was so important to Bigelow is ISS already has regular supply missions and already supports crew. If the first B330 is flight tested attached to ISS ISS crew can open the hatch, run tests, and escape to ISS should something go wrong. If the solution is a simple component swap the component can come up on the next scheduled delivery. Not having access to this logistics means Bigelow has to spring for a launch every time they run into a minor unexpected problem. If crew needs to evacuate the only option is escape to Earth. Time wise this means we're looking at ~1 year to certification berthed to ISS versus ~3 yrs without the logistics support. Those extra launches are going to cost Bigelow some hundreds of million too,

Disclaimer: My personal preference is Axiom over Bigelow. I tried to set my personal bias aside but I'm only human. Sorry if I still came off as an Axiom fanboi gloating.

Astroboffins peeved as SpaceX's Starlink sats block meteor spotting – and could make us miss a killer asteroid

IT Poser

Re: How many such exposures are going to be messed up like that?

Not that many since most astronomers have transitioned away from photographic plates.

What you should be asking is how many pixels will be corrupted. While this varies depending on the setup, we're talking a small fraction. There's no free lunch here but it isn't the end of astronomy either.

Boffins blow hot and cold over li-ion battery that can cut leccy car recharging to '10 mins'

IT Poser

Re: Charge or just swap the batteries?

You're an outlier.

I'm an outlier too. My concern is the natural gas storage that keeps my heat on in winter. The US natural gas storage system stores on the order of 4000 billion cubic feet(~110 billion cubic meters). In theory we could replace this with batteries, but we'll need >1.2 trillion kWh. At current battery prices we are looking at a ~quadrillion(10^15) dollar bill, not including installation. Then there is the cost to upgrade the electrical grid to consider. I'm having a hard time seeing how to afford the infrastructure upgrades.

An alternative would be to use the same Victorian era technology SpaceX is planning to use to make rocket fuel on Mars, the Sabatier reaction. This option allows us to continue using the existing natural gas storage, transmission, and distribution system, thereby allowing carbon neutral heating without spending that quadrillion+ dollars in infrastructure upgrades. Sure, the Sabatier reaction is lossy. With solar installations running at about $1/W a quadrillion dollars could theoretically buy enough solar panels to generate the electricity needed to completely fill US natural gas storage in roughly three hours. More realistically, the US is looking at costs on the order of $2 trillion to make our natural gas storage carbon neutral.

Returning to topic, methanol could be used for transportation and can also be produced by combining hydrogen and carbon dioxide in the presence of a catalyst. I'd have to do a lot of homework before I could run numbers, but I wouldn't be surprised if methanol fueled ICEs are a cheaper way to make transportation carbon neutral.

What's the scoop with Mars InSight's mired mole? It's digging again, thanks to trowel trickery

IT Poser

My homeland got bitchslapped by Turkey.

Team America: World Police isn't invading anywhere successfully anytime soon. Before we can even consider doing so we have to make America great again. Great like we haven't been since November 8th, 2016. Given how far we've fallen in less than three short years it is hard to ever see being great again.

Trump: Huawei ban will be lifted!
US Commerce Dept.: Yeah, about that…

IT Poser

Re: Wrong! He did a lot of efforts to avoid to be sent fighting in Vietnam.

Sorry for the downvote because overall we commiserate. Unfortunately Father "Fart", if I'm translating the British euphemism correctly, did the deeds.

Google's reCAPTCHA favors – you guessed it – Google: Duh, only a bot would refuse to sign into the Chocolate Factory

IT Poser

Well this explains a lot.

Sorry Google, the last time I logged in you were still pretending you weren't evil.

NASA goes commercial, publishes price for trips to the ISS – and it'll be multi-millionaires only for this noAirBNB

IT Poser

Re: An SLS/Orion launch for $666M?

Orion has four seats. Increasing the crew capacity by 50% won't halve the per seat cost.

Marginal launch costs for an SLS/Orion stack shouldn't be anywhere near that bad. I wouldn't be surprised if that figure could be as low as $500 million. The cost is in the army of workers suppliers Congress wants to fund. Congress wants this in the $3-4 billion range, preferably on the higher side. If we wanted to include development costs to make an apples to apples comparison with the commercial options we could easily be talking about $2+ billion per seat.

IT Poser

Re: The question is now: "Which moon?"

Endor of course. We need to get that fancy wall technology the president saw in a documentary. Even better, the Ewoks are going to pay for it.

IT Poser

An SLS/Orion launch for $666M?

Well you did say in order of increasing fictionalness. I'd say when pigs fly, but that is the point of SLS.

HPE's Spaceborne supercomputer returns to terra firma after 615 days on the ISS

IT Poser

Hold my beer...

""We said, 'Oh no, it will never wake up,' because pulling a plug on a Linux server is the worst thing you can do."

*Grabs aluminium, iron oxide, and magnesium*

Third time's a charm? SpaceX hopes to launch 60 Starlink broadband sats into orbit tonight

IT Poser

Re: 95 per cent of the components on each satellite will burn up

Very good questions. Many of the answers can be obtained or inferred from last fall's FCC modification filing my search skills are failing to find. From memory:

The 5% that don't burn up are older designs of components like reaction wheels and transmitter bits. These 60 satellites are a mix of new and old designs. 5% is an up to figure. Future satellites will replace the old component designs with whatever burns up during reentry that actually works in space. One major concern, laser interlink mirrors, will be added later, presumably when mirrors that burn up finish development.

The near-term goal is 100% burn up. I hope you agree that is an acceptable target.

NASA fingers the cause of two bungled satellite launches, $700m in losses, years of science crashing and burning...

IT Poser

Re: Insurance probably covered a lot of the losses

US government launches are typically not insured. IIRC neither of these payloads were.

Israeli Moon probe crashes at the last minute but SpaceX scores with Falcon Heavy launch

IT Poser

So close Beresheet, so close.

This wasn't the first time Beresheet's engine failed to burn. On February 26th we learned that Beresheet failed to conduct a scheduled burn[1][2]. The cause was a Single Event Effect[3], a radiation event that disrupted the computer. Beresheet's software was modified to make it more robust to these events[4].

There was a problem with the star trackers. Star trackers are notoriously difficult. SpaceIL handled that problem well.

As of now we don't have definitive word on what exactly went wrong during the landing burn. What we do know is that IMU2(inertial measurement units) failed and everything went sideways(literally and figuratively).

As Meatloaf sang, "Two outta three ain't bad." I, for one, hope the team gets another shot.

[1] http://www.israelnationalnews.com/News/Flash.aspx/449107

[2] https://www.timesofisrael.com/setback-for-israeli-lunar-lander-as-computer-glitch-prevents-scheduled-maneuver/

[3] https://radhome.gsfc.nasa.gov/radhome/see.htm

[4] https://forum.nasaspaceflight.com/index.php?topic=47217.msg1918211#msg1918211

If you really want to get your space geek on NSF(citation [4]) has over 400 mostly informative posts about Beresheet alone.

VP Mike Pence: I want Americans back on the Moon by 2024 (or before the Chinese get there)

IT Poser

Re: Is there a Mexican space programme?

Yes, the Agencia Espacial Mexicana was created in July, 2010. The preceding agency was Comisión Nacional del Espacio Exterior which was created in 2962. The budget is ~MXN$100 million, or about £400k.

NASA: We need commercial rockets! SLS: Oh no you don't!

IT Poser

Re: What's the running costs of ISS though?

The operations costs of ISS are on the order of $900 million per year. The science budget is ~$350 million. The lion's share of the costs, nearly $3 billion until we can't stop paying for Soyuz seats, is transportation.

"Also the ISS does some science that we simply can't do with robot probes. Which is the science of how to live in space. Which may, or may not, be important - depending on whether we ever have space-based industry."

We already have emerging microgravity manufacturing. See my reply to sean.fr for an overview. If the private sector research and manufacturing markets continue growing at the rate they have been for the last six years private industry will be able to support private space stations supplied by private rockets sometime in the mid to late 2020s.

In other words ISS is working better than anyone could have hoped a couple decades ago.

IT Poser

Re: all a waste of money

ISS gets roughly half of NASA's human spaceflight budget, or just short of $4 billion until Soyuz flights end. For comparison SLS/Orion has been getting roughly the same amount since 2011. The remaining ~$12 billion of NASA's budget goes to things like deep space probes.

What you are missing are the benefits from ISS.

IT angle: Thanks to having ISS two companies(Made in Space and Fiber Optics Made(???) in Space) are nearing production of microgravity drawn ZBLAN. The advantage of drawing ZBLAN fiber in microgravity is gravity induced crystals don't form, allowing fiber runs to be twelve times longer than is currently possible. Based on current fiber and repeater prices a single cargo Dragon should be able to return on the order of a billion dollars in profit each launch and landing.

While this one product would be enough to dwarf NASA's budget, ZBLAN isn't the only thing being worked on in the only lab not located on Earth. Pharmaceuticals companies like Merck are researching new drugs that can't be created in gravity. Another biomedical application is growing replacement organs without needing the scaffolding that is required on Earth. Budweiser is experimenting in how to brew space beer for the workers the above industries require.

This only covers companies that are publicizing their efforts. Most commercial work is employing security through obscurity.

Perhaps you don't want better fiber optic cables, drugs, replacement organs, and whatever else we discover is better to make in space. If so I can understand you calling ISS a waste. I don't share that opinion.

IT Poser

We're not that creative over here. It's merely called Senate Launch System.

Although considering the estimated 1:50 LOC(Loss of Crew) estimate Shuttle Lots Safer(1:90) might be the most descriptive option.

Earth's noggin took quite a clockin' back in the day: Now a second meteorite crater spotted under Greenland ice

IT Poser

Re: Hiawatha?

Your right about the name. Hiawatha was a co-founder of the Iroquois Confederacy circa early eighteenth century. The PC police won't complain about this name because it isn't European but its no less "wrong" than Victoria Crater would have been.

Sad relics of UK launch capability returned to Blighty while NASA fiddles with Boeing crew

IT Poser

Re: Galileo

Given the clock issues you might not be the only ones launching satellites to replace Galileo.

Man drives 6,000 miles to prove Uncle Sam's cellphone coverage maps are wrong – and, boy, did he manage it

IT Poser

Re: or at worst have the contract declared void.

And switch to who exactly?

The "other" provider* is promising 7G coverage. This is an entire 2G more that AT&T is selling**. Shirley it must be better.

* The reality is the signal comes from the same crappy tower which I can only hope gets upgraded to 3G one day.

** Yes, 5G doesn't actually exist yet, but let's not let facts get in the way of the advertising.

Third Soyuz does not explode while auditors resume poking around NASA's big rocket SLS

IT Poser

Re: the SLS's LH2-fuelled upper stage will always be more efficient

Not true. SEP(solar electric propulsion) in its current iteration is up to 10 times more propellant efficient, with theoretical margin to become an additional 10 times better.

NASA to celebrate 55th anniversary of first Moon landing by, er, deciding how to land humans on the Moon again

IT Poser

Re: Why did I read that initially as the first unscrewed mission?

Because with LOC(Loss of Crew) estimates that make Shuttle look safe, any crew riding on SLS/Orion has a very good change of having screws(and other spacecraft bits) involuntarily inserted.

Geoboffins baffled as Ceres is crawling with carbon organics

IT Poser

There is a definitive reason Ceres Organic Chemicals is targeting Ceres.

Scoff all you want, the remaining microbes on Ceres will lead to unexpected profits. I need $500 million to test my 5 tonne lander bringing back Lunar samples, then it's on. It being research on every hunk of rock with equal or lower gravity than Ceres, meaning almost everywhere humans can go with current technology, including Psyche 16.

5 reasons why America's Ctrl-Z on net neutrality rules is a GOOD thing

IT Poser

Richard 81,

You do realise Goodwin's Law has been extended to include references to "Snowflakes", right?

Actually "Snowflakes" is a corollary. AFAIK this particular corollary has not yet been rigorously defined. Feel free to create one. This information will be very useful as our AI develops psychohistory.

'Water on Mars' re-classified as just 'sand on Mars'

IT Poser

Re: Musk's idea to explode nukes at the poles has a vital flaw

Based on the little Martian exploration we've done, it appears that it took billions of years for the solar wind to create what we see today. Yes, the solar wind will eventually strip any Martian atmosphere, assuming we don't simply* develop an artificial planetary magnetic field. This will take millions of years. Unless your definition of long term human use is in time frames longer than humans have existed for, you have not stated a case against long term human use of Mars.

* Simple for a civilization with the technology to construct a colony on anther planet than is large enough to justify the effort in nuking the poles. We know how to build Dyson-Harrop satellites today. Dyson-Harrop satellites can harness solar energy to create large magnetic fields in space. The solar wind is made up of charged particles, principally protons and electrons. Charged particles can be influenced by magnetic fields. A constellation of Dyson-Harrop satellites in Martian orbit** therefore can deflect the solar wind. I expect, if a better method is not developed, this style of system can be refined to capture the solar wind. As protons plus electrons equals hydrogen, this is one potential way to import lost-cost hydrogen(We also end up with helium and traces of heavier elements) to Mars. The same system could also be used to give the Moon it's own magnetic field, allowing a Lunar atmosphere.

** You may have seen the proposal for a similar shield placed at the Sun Mars L1 point. This doesn't work because the solar wind hits from the side. The solar wind is influenced by the Sun's magnetic field, which is dragged by the Sun's rotation. The Sun's magnetic field, when viewed from above the orbital plane, looks like a pinwheel.

Tesla share crash amid Republican bid to kill off electric car tax break

IT Poser


My expectation is that, if we look at a longer sales period, we should see a peak in sales right before credits end and a valley right after. If I had been in the market for an EV in Georgia as the end of the credit approached, I would have bought sooner so I could still get the credit. I expect most people would do the same. Looking at sales from the months before the credit ends and the months after tells us nothing. What we want to know is how long it takes sales to recover at the new higher price point.

Unfortunately, when I search for EV sales data for Georgia, all that comes up are articles lamenting the valley in the first months after credits ended. What I'd like to find are sales figures from at least 6 months before and after the credit.

NASA reveals Curiosity 2020's 23-camera payload

IT Poser

Re: 23 cameras and yet...

Marvin the Martian was a Warner Bros creation. We know Marvin hasn't been assimilated yet because he hasn't been forced to give up his quest for galactic domination to become a talk show host.

Elon Musk says Harry Potter and Bob the Builder will get SpaceX flying to Mars

IT Poser

Re: ""exceed passenger airline levels of safety""

Based on what I found scattered throughout the Reddit AMA, the plan is to use methalox, not hypers, for control thrusters. These will be fed by the main fuel and oxidizer tanks using a pressure fed system. Cryo-cooling systems will not be used for the initial BFS flights. Instead boil-off will be controlled by venting.

Methalox cryo-cooling is a mostly solved problem. Musk acknowledged that it will be added so I expect there volume and mass reserved in the BFS designs to accommodate the system.

IT Poser

Re: "The Moon is harder because it has no atmosphere"

"Wouldn't the mere fact that there is at least *some* atmosphere on the Mars-side of your suit/vehicle/etc, compared with the vacuum encountered on the Moon or in orbit, make the design of said suits/vehicles a bit easier thanks to them not needing to cope with such a steep pressure differential?"

Yes. The pressure a suit has to contain is indeed nearly identical for Mars or the Moon, as others have pointed out. This isn't the end of the story though. Any useful pressure suit will leak. On Mars, we can recapture lost gases by compressing the tenuous atmosphere. This isn't possible on the Moon. It's far cheaper to refill our suit by compressing the Martian atmosphere than it is to ship carbon and nitrogen from Earth to the Moon. Economics dictate that the Lunar suit must leak less, therefore more we expect it to be more complex.

IT Poser

Re: "Having an atmosphere is not going to make Mars any easier."

Just because you fail to see how an atmosphere makes things easier doesn't mean that having an atmosphere makes things easier. Here is a very brief list of key advantages.

Areobraking - The amount of energy needed to send a craft from Earth to land on Mars and the Moon are similar because the Martian bound ship doesn't have to use fuel to cancel orbital velocities.

Micrometeorite shielding - Specs of dust are an impact hazard on the Moon. The Martian atmosphere eliminates this potential threat.

Radiation shielding - The Martian atmosphere provides far more than the Lunar lack-of-atmosphere.

Temperature regulation - The Martian atmosphere traps enough heat that we can deal with the night time cold. Even with a P-238 heating element, the most recent lunar rover began malfunctioning after only one Lunar night. Solar powered robots without a P-238 heating element can survive over a decade on Mars.

Extractable resources - The Martian atmosphere is an easily processed source of carbon and nitrogen. Virtually all of the chemistry we use involves carbon and nitrogen. A colony will require tons of carbon and nitrogen reserves per person. Based on current knowledge, there are no extracable carbon or nitrogen sources on the Moon.

The last point is very important. Each colonist will require a carbon reserve of 12+ tonnes for the agrarian sector of the economy. When we start adding other economic sectors, such as textiles, plastics, and metallurgy, the per-colonist reserve necessary grows rapidly. On Mars CO2 capture and recycling doesn't have to be perfect. We can simply compress more atmosphere if we need more carbon. Every loss on the Moon has to be replaced with imports. Capturing the CO2 emmissions from aluminium production is going to add mass and complexity, with necessary higher price tag, of Lunar equipment compared to equipment that does the same job on Mars.

The only advantage that the Moon has, and this isn't based on current technology, is travel time.

Musk: Come ride my Big F**king Rocket to Mars

IT Poser

Re: I would prefer that all SOCIALIST spending be dropped in favor of rockets to Mars.

So you want to replace one set of socialist programs with the set of socialist programs you prefer.

That will go over really well. /sarc

Hotter than the Sun: JET – Earth’s biggest fusion reactor, in Culham

IT Poser

Re: Clear day in the UK?

Wouldn't it require less waiting to design and build a working fusion power plant?

IT Poser


We'd all love to have materials that could be used to make solar panels with the ability to withstand the expected radiation levels inside a fusion core. AFAIK, no one has discovered the right materials yet.

You'll have to describe how you envision wind turbines functioning inside a fusion reactor core. I can't think of any way to make the extra effort worth the trouble.

Brit broke anti-terror law by refusing to cough up passwords to cops

IT Poser

Re: The border police won't ask you for your MEGA password,

What is MEGA?

What do you mean I should know? Let me have my computer, I need to Ask Jeeves.