The tube is not loadbearing, "jackass". It exists soley for its neutronicity.

The cost of lifting ~10t of fuel for a 10-50t spacecraft+cargo (e.g. depending on how extreme dV they actually want the spacecraft to be capable of) - aka, for a very large mission (the Apollo LM was only 4t incl. fuel) - at Falcon 9 prices - is 15M. At Starship prices, like an order of magnitude or more less. This is nothing compared to the billions of dollars you'll spend developing the spacecraft and billions more on mission hardware.

You have the most insane ideas.

? It's not a fusion rocket.

It's a fission rocket - bloody close enough.

additionally, have you factored the weight and storage space lost on the fusion rocket, to make room for 2x the fuel,

It's an ISP of 5000, it doesn't matter.

If you want to get there quickly, you're always loading it fully with fuel. The only difference is in the transfer time. All of them are "very fast", just varying degrees of "very fast".

It's like trying to say we should only fly airplanes on the couple days per year when the jet stream is strongest. It's such an immensely stupid idea.

1) the 'now 2 months' is down from the 'best time of 6 months', caused by mars being literally closer to the earth.

That's not how Hohmann transfers work. Just stop. And a minimum energy transfer to Mars is 9 months anyway, not 6.

In order to achieve the 2 month travel time, it must launch WITHIN THE LAUNCH WINDOW.

Get this through your head: There Are No 'Launch Windows' With Nuclear Propulsion. You don't leave a craft that can travel to Mars a matter of months sitting idle rusting away rather than repeatedly ferrying back and forth, just because some times the trajectory is somewhat longer and others it's somewhat shorter.

There are launch windows with minimum energy Hohmann transfers because that's what you need to have Mars be at the right place when you intersect its orbit. It takes roughly the same amount of energy to intersect Mars's orbit regardless of when you launch a Hohmann transfer, but unless you time it right, Mars won't be there. Launching at any other time requires more dV to dogleg it - and dV is dearly bought when it comes to chemical rockets. It isn't dearly bought with nuclear rockets. So launch windows simply don't apply to them. You launch on an elliptic which doesn't terminate at Mars' orbit, aka you applied more delta-V than was necessary to get out that far, but that's happening by definition if you want to get there faster. A minimum energy elliptic can only intersect Mars orbit opposite its starting position, but the higher the energy of the transfer, the more rotated the interception point is.

I will repeat: your capital cost is in your rocket. You're not going to leave it sitting around waiting for 2 1/2 years when you could do 10-ish trips during that timeperiod, just because some are longer than others and some somewhat shorter, and thus raise your capital cost per kg tenfold. They're all varying degrees of "short", and you have flexibility; you're launching on all of them. Unless you're an utter moron who likes throwing away 10x more capital at a project. You do not have to intersect the planet at a specific location on its orbit in opposition to your starting point when you apply more than the minimum dV.

since the ships ARE NOT THOUSANDS OF KM APART, due to ALL LAUNCHING IN THE SAME WINDOW

Launching just days apart in the same window (which again, THERE ARE NO WINDOWS), they're MILLIONS of kilometers apart. Do you not even know how far Mars and Earth are apart, or can you not divide a travel distance by the number of days of the trip?

And for the last goddamn time, the exhaust doesn't even remotely resemble a collimated beam, even if it did it would still be orders of magnitude weaker than ambient radiation, and even if it wasn't all you had to do was microscopically off-angle it. This is such a stupid line of discussion.

Yes, and you clearly don't.

Nobody is going to leave the capital investment of a spacecraft that can do such quick transfers sitting idle waiting for a "window" when they can head there and back repeatedly in the same timeperiod.

Your costs are in your spacecraft, not your fuel. You're not going to leave it sitting idle for years waiting for a "window" to make a single delivery when you could make ten deliveries in that same timeperiod. Doing the former would mean increasing your capital costs by an order of magnitude per unit cargo shipped. Which is a braindead idea.

If your goal is "don't work on researching new technology until you've fully solved all of the problems at home", then I have to ask, how do you enjoy living a hunter-gatherer existence? You're setting a standard to never do basic research, because there will always be problems.

Nobody is saying "dump half of the globe's GDP into space exploration". The world's space agencies spend like one twentieth of a percent of global GDP. And have spawned a massive commercial market in things that benefit life on Earth, which is far larger than what space agencies spend (total space revenue now amounts for about half a percent of global GDP). All of those satellites orbiting Earth aren't up there on a lark, they're doing so because they're profitable to have them up there, because they provide services to the people of the world that people want to pay for. Global communication (particularly in remote areas for ships, planes, and emergency responders, and now increasingly, rural broadband), global positioning and timing, weather monitoring, fire monitoring, other natural disaster monitoring, climate monitoring, scientific research, agricultural management, resource mapping, national security, disaster response, media broadcast, on and on and on.

Basic research is your seed corn; you don't boil and eat it. Basic research is useless until it very suddenly isn't. "OMG, look at all these people wasting all this money trying to make heavier than air machines fly, when we have all these problems to deal with on the ground!" Sure would have been a GREAT idea if we had listened to those people, huh?

Do you understand what the word "parallel" means (aka, "not entering the planet"), and that these particles are rapidly en route to escape the solar system at several thousand kilometers per second? You're not catching up with them. Ever.

It's just nonsense. It's not even a highly collimated stream, and even if it were, you could just angle it slightly off-axis. It's moving away from you at relativistic speeds, and it's versus an environment that's already awash in radiation.

You simply do not understand orbital dynamics. You're referring to Hohmann Transfers. They're irrelevant if you're applying extra dV, which is what this entire article is about. There are no "windows" with nuclear propulsion. Nobody is going to leave the capital investment of a spacecraft that can do such quick transfers sitting idle waiting for a "window" when they can head there and back repeatedly in the same timeperiod.

Furthermore, even if we pretended it was just a few days apart (aka, even if we pretend nonsense) - On, say, a 200m km trip in 75 days, 2 days apart is over 5 million kilometers distance. You'd struggle to see a high powered laser pointed right at you from that distance. You're not going to increase radiation over background. Period. Even if the stream was super-collimated, which it isn't even remotely.

It's nonsense. Just stop.

1) There are no "launch windows" with nuclear propulsion. You're not doing Hohmann transfers anymore.

2) You couldn't contaminate the next spaceship from millions of kilometers away if you literally tried to do so. You're not going to be detectable above the (already significant) background radiation, by orders of magnitude.

3) "Contamination" implies something that persists. Not something that buggers off out of the solar system at a speed of thousands of kilometers per second. Distance from Earth to Pluto in just a week or two.

Stop thinking like a 19th century industrialist.

Start understanding the mind-boggling vastness of space and the already immense radiation load therein.

You don't have to be that far off-axis / distance before you've diffused to less than the (already significant) space background radiation. Remember that the distances we're talking about here are tens of millions of kilometers. Kinda hard to irradiate people from those distances even if you tried.

There is no "contamination of space". The exhaust is much faster than escape velocity from the solar system. Thousands of kilometers per second.

Aldrin cyclers make no sense as cargo haulers. They don't save you dV or time - they cost you more dV and time to dock with them vs. taking an optimal direct trajectory. The point of an Aldrin cycler is that you can have a big spacecraft with tons of radiation shielding and nice facilities for humans on their long trip to Mars, which you don't have to loft every single trip. But it provides no advantages for cargo, only the aforementioned disadvantages.

And Aldrin cyclers are premised on long transit times. But if you can do fast transits with nuclear propulsion, it does rather reduce the appeal. If you want fast Aldrin cyclers, they have to take highly elliptical orbits that only reach the inner solar system rarely, so you need an awful lot of them. And once again, they don't save you dV or time, they only cost your spacecraft that has to dock with them dV + time vs. a direct transfer.

To be fair, you don't decelerate pointing directly at a planet (if you even decelerate by rocket power at all, rather than aerocapture). The deceleration burn is parallel to the planet. You don't want to fall straight down onto it.

Though I mean... I guess with this sort of thrust to weight ratio, you *could* design a spacecraft where this could give you powered flight all the way to the surface ;) Still, pretty wasteful; nuclear fuel doesn't grow on trees.

Then again, if you built the craft with enough thrust to pull positive Gs on Mars, then you could *take off* as well... if you're willing to contaminate your landing pad ;) Probably best to have a small chemical stage to get you well clear of your settlement at least.

I do find this interesting that this is basically yet another more modern, more realistic design of Orion (pulse propulsion by small nuclear bombs) - yet people will still keep referencing Orion as their dream rocket, even though it's an obsolete design that's been far surpassed by many other contenders.

"Compare any of that with the previous horrendous level of censorship"

What on Earth are you talking about? How long, year after year, did Trump spout vile racist offensive garbage without any action taken against him ? The question isn't "why did he eventually get banned", but "why on Earth was he allowed to violate Twitter's policies endlessly in the first place"?

. It is way better on X now.

Lol, is this some type of a joke? Every time I pop back onto Twitter it's like a dystopia. A constant stream of bots and spam, endless ads, bluechecks with inane views boosted to the top, and a constant push from the site to try to upsell you to Twitter Premium. I can only conclude that for people at the site it's been a boiling-frog situation that keeps them from noticing the change.

We're all made of the same stuff.

Up until around six weeks, there's no difference between male and female embryos. At that point, a tiny region (usually) found on the Y chromosome called SRY activates. Less than 1000 base pairs, its job is to start the virilization cascade. It's highly mutable, so it tends to be prone to "breaking" or transferring between X and Y - leading to XX males and XY females. But XX males lack the azoospermia factor in the Y chromosome's long arm and XY females have streak gonads, so while this randomly happens, they're infertile and the mutation doesn't persist. But otherwise they're phenotypically normal men and women, up to the point of infertility in XX men and a lack of puberty (due to the nonfunctional streak gonads) in XY women.

At the start of the virilization cascade, everyone has the same basic set of organs, including the urogenital sinus, paramesonephric (Müllerian) ducts, and the mesonephric (Wolffian) duct. These are to form the common, female, and male organs, respectively. The paramesonephric ducts will develop if not exposed to anti-Müllerian hormone (AMH), and will fail to develop / degenerate if exposed to it. The mesonephric duct will develop if exposed to testosterone and fail to develop / degenerate if not exposed to it. Note that this is two different hormones - more on that mix-and-match later.

Most aspects of the genitals however come from the common urogenital sinus, leading to cognates in both males and females: labia-scrotum, clitoris-glans, prostate/paraurethral glands (as well as the lower 2/3rds of the vagina). This leads to a smooth interpolation between the two (diagram here). To reiterate, these pairs are the same organ, just grown to different shapes / sizes. A glans is a large clitoris. The scrotum is fused labia. Etc.

So we've already accumulated quite a list of things that can go wrong, including defective SRY, transferred SRY, unusual karotypes (X0, XXY, XYY, XXX, XXYY, etc), presence / absence of AMH without the absence / presence of testosterone, insensitivity to AMH / testosterone, etc. Using a very broad definition of intersex (e.g. including unusual karyotypes, such as Kleinfelter syndrome (XXY), up to 1,7% of the population deviates from the normal developmental process. For visibly ambiguous genitals, it's about 1 in 5500. A couple examples:

Androgen Insensitivity Syndrome (AIS): a largely (PAIS) or complete (CAIS) phenotypically normal female, but XY. Generally infertile. Exposed to androgens in the womb but don't react sufficiently or at all to them. Generally identify as female.

5-alpha reductase 2 deficiency: XY, but the body doesn't produce much / any 5aR2D, which converts testosterone into the more potent dihydrotestosterone (DHT). Born largely phenotypically female, but at puberty the testes descend, the voice deepens, the clitoris enlarges, and they undergo a relatively normal male puberty - leading to the nickname in the Dominican Republic (where it's most common) of "guevedoces" ("balls at twelve"). Despite being raised female, they typically identify as male, and - with medical assistance can sometimes father children.

Of course, in addition to primary sex characteristics you have secondary sex characteristics, developing at puberty due to whatever hormones the person is exposed to. E.g. one's larynx isn't taking a gander at what genitals one has - if it's exposed to testosterone, the voice will deepend, and if not it won't. Same with body hair, breast development, etc. E.g. male nipples aren't atavisms; they're just undeveloped tissues that never got the signal to develop. One is reminded of the scene in "Meet the Parents" where Greg, trying to impress his would-be father-in-law describes milking a cat, and says anything with nipples can be milked - to which the father in law replies, "I have nipples, Greg - can you milk me?" Except, yes, the answer to this is "yes" - expose his body to estrogen to develop the breasts, then to prolactin, and he'd lactate just like anyone else.

To loop back: we're all made of the same stuff.

... as opposed to just random ignorant press fluff, here you go.

TL/DR: it's a gun that shoots fission plasma like little nuclear bombs. A 2,2kg projectile containing low-enriched uranium (LEU) and a moderator is fired (once per second) by a coilgun through a a flared 522kg 33cm-long LEU barrel (with the barrel flaring out in a HEU section at the base) at 1600 m/s (requiring 5MW of power), where it hits criticality. By a third of the way through the barrel its interior is already 1eV / 11605K, then is boosted to 500 eV by the HEU section as it leaves the barrel into a parabolic magnetic nozzle to direct the plasma. The fact that the projectiles move through in pulses makes it easier to cool the barrel, given that the thermal power present in the first third of the barrel is 5,4TW, and in the latter section, a peak of 46TW; obviously you're not going to withstand that continuously! 1% of the power from the explosion is recovered via coils, returning 29MW to the system, to power the gun and any other spacecraft needs. The result - 100kN of thrust at 5000 sec Isp, would be enough to lift 10 tonnes of mass from the surface of the Earth (not that you'd use it on the surface), and has a propellant efficiency 14x that of Starship's Raptor engines.

Obviously, this rocket is dirty, but almost everything from the explosion will have a velocity higher than the escape velocity of the solar system, so so long as you're not pointing it directly at Earth, it doesn't matter. Not that one engine firing in the direction of Earth would matter all that much anyway, but...