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Musk revises Mars ambitions

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Re: Musk revises Mars ambitions

#171

Post by wahern »

elorant wrote: post #53
benjaminl wrote: post #22

I don't understand why people are so quick to dismiss SpaceX's ambitions as unrealistic. They were the first to achieve re-usability of the first stage of an orbital class rocket, the first to prove out supersonic retro-propulsion and the first private company to re-fly a spacecraft (the Dragon Capsule). Given that, it seems like they should be given the benefit of the doubt when they say they are going to do somethi…

It's unrealistic because it requires a ridiculous amount of money to go there and establish a colony. The kind of money only states can spend, and probably for an endeavor like this it will require a multinational collaboration. No private company can amass that kind of money because shareholders and investors can't see the ROI in this thing.

As of 2017, world wide financial assets (stocks, bonds, and notes; _excluding_ real estate and capital assets) amount to nearly $300 trillion. (Trillion, not billion.) Only about 20% of that is public debt.

Private industry sits on a tremendous amount liquid wealth. And because of income inequality, it's actually principally controlled by a relatively small number of people.

In other words, not only is private industry capable of financing a Mars mission, the reality is that private financing may be the _only_ realistic option.

For any skeptic wondering how Musk is able to "sucker" so many investors, this is why--there's just a god-awful amount of private money looking for even the most meager gains.

Note that the Federal Reserve's QE2 amounted to only $2 trillion, less than 1% of global financial assets. If you think quantitative easing has led to an asset bubble, think again. Or rather, think bigger. Whatever you think, just realize that we're living in a brave new word with wealth beyond what anybody can scarcely imagine even today. Few people, if any, understand either the possibilities or systemic risks. The magnitude of things, and the speed with which it evolved, is mind boggling.

Re: Musk revises Mars ambitions

#172

Post by ajnin »

godelski wrote: post #137
iamcreasy wrote: post #122

Earlier quoted context omitted.

Here is what Elon said on instrgram, "Fly to most places on Earth in under 30 mins and anywhere in under 60. Cost per seat should be about the same as full fare economy in an aircraft. Forgot to mention that." Source : https://www.instagram.com/p/BZnVfWxgdLe/?hl=en&taken-by=elon...

Which gives evidence to my guess. Because there is no way you can do a rocket for anywhere near that price. I mean, let's do some quick math. We'll even give him buffer room. Let's say you can get 50 passengers at $5k per ticket. That's $250k/flight. I just can't see how that would cover the flight (fuel), let alone things like: maintenance, licensing, insurance, and the staff to operate the facilities. Let alone doi…

He mentions in his presentation that the BFR will have more pressurized cargo space than an A380, which can carry 853 passengers in an all-economy configuration. Let's say the BFR would carry a bit more that that, and prices would be a bit less than $1k, that would bring the flight budget in the order of $500k to $1M very roughly.

Let's try to estimate fuel costs, according to Wikipedia (https://en.wikipedia.org/wiki/Interplanetary_Transport_Syste...) propellant costs $168 per tonne, and the spaceship can hold 1950t of it, so assuming one full tank per trip, that's $328k for fuel.

The actual cost of the rocket is around $200M, assuming a service life of 1000 flights, that's a $200k amortized cost per flight.

Add a few hundred k for launchpad, personnel, administrative costs of various kinds, and you get in the $500k to $1M ballpark.

So on the back of the envelope it looks about break-even. Maybe there's a sufficient market of people willing to pay a premium for very fast travel to make this profitable.

Re: Musk revises Mars ambitions

#173

Post by Hypx »

ChuckMcM wrote: post #101
Hypx wrote: post #46

Earlier quoted context omitted.

Just want to point out some misconceptions here: Arguably, the Space Shuttle was the first launch system to reuse the first stage, and the first to prove retro-propulsion landing was the Delta Clipper (on Earth anyways, supersonic retro-propulsion was used on other planetary bodies earlier). First private company to refly a spacecraft was probably SpaceShipOne, although this was suborbital not orbital. Not saying wha…

Let's look at the claims from the parent: * re-usability of the first stage of an orbital class rocket, I think the shuttle argument has some merit, it was certainly designed to be re-usable. However the first stage was a blend of the SSME's and the SRB's. While the SRB's were "refurbed" it really was re-manufactured. The shuttle and its SSMEs were closer to what F9 does today. * the first to prove out supersonic ret…

This claim needs some scrutiny:

>> * the first to prove out supersonic retro-propulsion

> Here the key is supersonic retro-propulsion. They really were the first people to light up a rocket engine facing the 'wrong' way of a supersonic spacecraft. NASA's interplanetary systems have all used parachutes to get into the sub-sonic regime before firing retro-rockets. Neither retro-propulsion in orbit (nominally a vacuum) or on the Moon count as supersonic.

All retropulsive landings are rockets facing the "wrong" way. That's true on Mars, the Moon, or Earth.

By the semantics of your argument, neither does the Falcon 9 experience supersonic retropulsive landing, since the only time it fires at supersonic speeds is in the near vacuum state of the upper atmosphere. The descent down to Earth is a guided free-fall and the last step happens at subsonic speeds.

On Mars, terminal velocity for a probe is supersonic, so the parachute stage is required to reach subsonic speeds. It basically replaces the guided free-fall of the Falcon 9 rocket, and make things harder, not easier. It should be pointed out that the full process of landing on Mars involves an insane Rube Goldberg contraption of heat shield, parachutes, retropulsive rockets, airbags, and sometimes a skyscrane. Claiming that what SpaceX is doing is a harder problem than this is simply wrong.

Finally, the Delta Clipper did pretty much exactly what the Falcon 9 did, and so did Blue Origin with their New Shepard rocket. So the concept in its near entirety was well-known for a while.

> They are also the first company to launch two rockets into orbit in a single weekend.

Not from the same launchpad. Many organizations have launched rockets nearly back-to-back, some even from the same launchpad.

> So at what point would SpaceX's achievements become "impressive" for you without having to add context?

Not really what was being argued here. Certainly, what SpaceX has done is impressive with or without context. But the claim that they are magically beyond everyone else is just wrong. Looking at their achievements in context shows their limitations, and that they are not exactly the "first to X" where X is something someone else has long figured out but the poster is unaware.

Re: Musk revises Mars ambitions

#174

Post by Nomentatus »

pacificmint wrote: post #142
r00fus wrote: post #62

I'm absolutely ecstatic that Musk is talking about the Moon. Mars is great, but Luna is near & here, and honestly, it's a strategic location (not just militarily) as the it's at the top of Earth's gravity well with a minimal well of it's own - great basecamp for interplanetary missions. If we can't occupy the Moon, why should we shoot for colonizing Mars?

There is a school of thought that building a sustainable base on the moon is actually harder than Mars. Some of the reasons: * No atmosphere, no source for Oxygen and Carbon * 28 day night/day cycle, hard to keep your base power over the 14 day night * Unclear if water can be found * Lower gravity Potentially this means that way more resources would have to be brought in from the outside than on Mars. (If this is rea…

Carbon and oxygen are available in lunar soil, hydrogen is another matter.

Re: Musk revises Mars ambitions

#175

Post by Nomentatus »

mkempe wrote: post #80
r00fus wrote: post #62

I'm absolutely ecstatic that Musk is talking about the Moon. Mars is great, but Luna is near & here, and honestly, it's a strategic location (not just militarily) as the it's at the top of Earth's gravity well with a minimal well of it's own - great basecamp for interplanetary missions. If we can't occupy the Moon, why should we shoot for colonizing Mars?

Another interesting aspect of a moon base -- would it be easier and/or cheaper to produce propellants there instead of sending four rockets up to fuel each Mars-bound ship?

Yes. Oxygen is plentiful in the soil. You might have to bring your own hydrogen, but it's nothing if not light.

Re: Musk revises Mars ambitions

#176

Post by Nomentatus »

danblick wrote: post #8

Sending humans to Mars seems less attractive to me than sending robots to Ceres. Is there an argument for Mars that doesn't include the phrase "multi-planet species"?

Colonization has, previously in history, always required an export from the colony. Carbon might be that, for Mars (from CO2 ice.) Or possibly hydrogen, although that's abundant in asteroids, Ceres, etc.

Re: Musk revises Mars ambitions

#177

Post by amorphid »

reilly3000 wrote: post #128
semi-extrinsic wrote: post #121

Earlier quoted context omitted.

> Interplanetary space travel is going nowhere fast because there is no profit motive. This is so very true. We can do it for Science, and for fun, but not much else.

What happens when earth goes to actual shit and rich people want out?

That's a theme in Elysium.

http://imdb.com/title/tt1535108/

Re: Musk revises Mars ambitions

#178

Post by kyberias »

varjag wrote: post #49
kyberias wrote: post #42

Earlier quoted context omitted.

I don't understand why any of that is a huge proof that they can go to Mars.

There are no true proofs outside of realm of math at all. SpaceX odds for going to Mars are, however, better than anyone else's.

SpaceX hasn't done any manned spaceflights and hasn't flown anything to Mars.

NASA, for example, has done that multiple times.

So why exactly are SpaceX odds better (@ succeeding)?

That rocket landing to the platform flying backwards looks awesome but I don't think it significantly increases their odds for Mars flight. Will they fly there backwards with a similar platform waiting?

Re: Musk revises Mars ambitions

#179

Post by godelski »

ajnin wrote: post #172
godelski wrote: post #137

Earlier quoted context omitted.

Which gives evidence to my guess. Because there is no way you can do a rocket for anywhere near that price. I mean, let's do some quick math. We'll even give him buffer room. Let's say you can get 50 passengers at $5k per ticket. That's $250k/flight. I just can't see how that would cover the flight (fuel), let alone things like: maintenance, licensing, insurance, and the staff to operate the facilities. Let alone doi…

He mentions in his presentation that the BFR will have more pressurized cargo space than an A380, which can carry 853 passengers in an all-economy configuration. Let's say the BFR would carry a bit more that that, and prices would be a bit less than $1k, that would bring the flight budget in the order of $500k to $1M very roughly. Let's try to estimate fuel costs, according to Wikipedia ( https://en.wikipedia.org/wik…

I didn't realize he said 853 passengers. In the article it mentions 40 cabins. So I rounded to 50. We still don't get enough for fuel. And 1000 flights is pretty optimistic. Especially at this stage. Their rockets already aren't fully reusable (only just having tested reuse) and they have to replace parts. 10 flights is optimistic, let alone 1k. I'm sure we'll get there at some point, but I see no evidence of that technology currently.

I'm just saying that there are a lot of red flags and that one should be really skeptical.

Re: Musk revises Mars ambitions

#180

Post by greglindahl »

kyberias wrote: post #178
varjag wrote: post #49

Earlier quoted context omitted.

There are no true proofs outside of realm of math at all. SpaceX odds for going to Mars are, however, better than anyone else's.

SpaceX hasn't done any manned spaceflights and hasn't flown anything to Mars. NASA, for example, has done that multiple times. So why exactly are SpaceX odds better (@ succeeding)? That rocket landing to the platform flying backwards looks awesome but I don't think it significantly increases their odds for Mars flight. Will they fly there backwards with a similar platform waiting?

Good thing that NASA and SpaceX are working together to upgrade Dragon 1 to Dragon Crew.

As for what SpaceX (and OrbitalATK) does better, look at the cost of ISS cargo deliveries, and then read about the history of Constellation and Ares.

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