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A rocket a day keeps the high costs away (1993)

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Re: A rocket a day keeps the high costs away (1993)

#81

Post by tsimionescu »

SCM-Enthusiast wrote: post #52
btilly wrote: post #11

Earlier quoted context omitted.

Actually, reusability was an obvious idea from the start. For example the Space Shuttle and the McDonnell Douglas DC-X are examples of attempts at reusability in the USA, and other countries had their own experiments. It just became non-obvious that it was the right approach after a long history of failed attempts at it.

it was always the "Right approach" and everyone knew that there was nothing in the laws of physics that prohibits this. But you are writing that as if it's still be solved. No one has ever had a fully reusable orbital rocket.. still to this day. Althought starships got a shot.

It should be noted that reusable rockets are fundamentally less cargo per trip than non-reusable ones, since the reusable rockets have to carry extra fuel for re-entry. The sweetspot of having enough mass to orbit so that this reduced capacity is still worth it is not at all easy to reach.

In general, if rocket building costs could really be reduced to almost nothing, reusable rockets would be useless. The only case where reusable rockets have a chance is if building rockets is still very expensive.

Re: A rocket a day keeps the high costs away (1993)

#82

Post by tsimionescu »

bryanlarsen wrote: post #41
LeifCarrotson wrote: post #29

Earlier quoted context omitted.

That's not realistic simply because of the carbon requirements. Long haul aviation only burns a couple hundred kg of jet fuel per passenger. (I don't know how the top-level comment is calculating 1-3 tonnes of CO2 per passenger, Contrail effects? Construction of the plane? Altitude? Incomplete combustion? but a 250-passenger 787 doesn't carry 750,000 kg of fuel, it only fits 100,000 kg at most, plus plenty of reserve…

Starship has the size to carry about 400 passengers. Both stages together carry about 5,000t of propellant. But over 3/4 of that is liquid oxygen, and most of that is the first stage. The second stage alone with 1200t of propellant can't put humans into orbit, but it does have a range comparable to that of a 787. So 300t of liquid methane will get 400 passengers about as far as a 787 can get 250 passengers with 100t…

Starship has nowhere near the capacity to carry 400 passengers - people are not sardines you can just stuff into the rocket like you can satellites. You need plenty of equipment per person for manned spaceflight. Much more so if you want to compete with business class flying.

Also, the total travel time would be horrible, since you can't have a rocket launch/landing facility anywhere near a city, and loading and unloading a rocket is an immensely time consuming process. Plus, you never ever load people into a an already fuelled rocket.

Re: A rocket a day keeps the high costs away (1993)

#83

Post by tsimionescu »

cma wrote: post #22
lkbm wrote: post #17

Earlier quoted context omitted.

There are thousands of long-haul flights—and something like 100k flights overall—per day. If we're doing 10k+ rocket launches per day, then that's a huge problem. If we're doing 1 per day, it's a rounding error. This is premature optimization. (Either way, the solution, of course, is a carbon tax to price in the emissions.)

Elon said by 2028 they will be in active passenger service replacing long haul aviation for cheaper than a business class ticket.

Elon says many things, but this is one of the silliest ideas.

The experience of such a flight would be horrible. It all starts some weeks or months before with an extremely thorough physical check-up to make sure you are still able to withstand a rocket launch. On the day, you drive/sail to the middle of nowhere, at least an houror two out from any major city. Then, you get dressed into a used space suit - this takes experienced astronauts a good 10 minutes. You then board the rocket. Once everyone else is boarded and some pre-flight checks are successful, the fuelling starts. It will take a few hours, so hopefully they have good on-board entertainment.

Then, finally the rocket is ready to launch, and you get shot up into the atmosphere at an acceleration that is likely to make you pass out. Of course, this all happens with extremely tight noise canceling headphones to prevent your eardrums from bursting. But it's OK, you'll only wear them for an hour or so, and they may even allow you to take them off for a few minutes while you're coasting in the upper atmosphere. Then the deceleration will be just as enjoyable on the way down, of course. After you disembark and off the suit, you're now just a few short hours away from your actual destination.

There is 0 chance this will ever be allowed as a service for consumers, or that it would ever compete with business flights. It might make a cool tourism experience, but probably just up and down at the same place, no point in actually moving around.

Re: A rocket a day keeps the high costs away (1993)

#84

Post by dotnet00 »

adastra22 wrote: post #79
dotnet00 wrote: post #68

Earlier quoted context omitted.

They're running out of money and can't really get the kind of money needed to continue on the rocket R&D, so they're trying to stick to their satellite components business to stay alive until they can attract funding. Plus, they're kind of at a bad point and time in the market as small launch is not as lucrative as they hoped but moving up to medium lift is a big hurdle. So far, SpaceX is the only 'new space' launch…

Rocket Lab is doing alright.

Rocket Lab are in development hell at the moment and while their financials are decent, Electron has had a failure every few launches and Neutron is due NET 2024, but with no news of an Archimedes hot fire, it seems unlikely that we'll see anything before mid 2025.

By saying development hell I'm saying that other new space companies other than SpaceX are in that difficult in between point where they're burning cash on developing the rocket without yet being able to sell significant rides and without the leverage of knowing that the government will give you a blank check if you run out of money.

The important factor being that small launch doesn't make enough money to fully fund medium launch, there just isn't enough demand for small launch with rideshares being cheaper. However, medium launch can fund more medium launch or even heavy launch, as there is much more demand in the medium weight range.

Re: A rocket a day keeps the high costs away (1993)

#85

Post by Earw0rm »

contrarian1234 wrote: post #73

“then the frontier would open as the great railway to orbit supplanted the first generation wagon trains“ Except the frontier had fertile lands and vast potential. It was not a cold barren emptiness. You could also make access to Antarctica cheap and affordable at scale. It wouldn't suddenly make it economically sensible to go there I'm skeptical there is a huge amount of pent up demand that is just itching for lower…

The frontier was, in large parts, already full of people. Or at least had been until they died of smallpox.

Then we spent the next 150 years conveniently writing them out of history.

Re: A rocket a day keeps the high costs away (1993)

#86

Post by twic »

m4rtink wrote: post #62
twic wrote: post #13

Earlier quoted context omitted.

Before Starlink, SpaceX assumed/hoped that a mass of new customers would come out of the woodwork when cheap launches became available (the easyJet strategy!). When they didn't, they came up with Starlink to be that customer.

Sure, they might have guessed the scale or ramp-up wrong, I would still argue there is quite a few more launches now happening than there would be without Space X jump-starting the whole thing. Still, not being fully dependent on that certainly helps. :)

Oh, there are definitely more! The question is whether, without Starlink, there are enough for SpaceX's vision to be viable.

Re: A rocket a day keeps the high costs away (1993)

#87

Post by looofooo »

dotnet00 wrote: post #70
looofooo wrote: post #35

Earlier quoted context omitted.

What would another James Webb Telescope would have cost? Far far less then the first. Sure it is costly to destroy a prototype, but not as much as you think.

That only works when you're doing something like Starlink or Starship's development, where losing some prototypes is fine. However, that's not how JWST was designed, so losing many prototypes of it would be very costly. If JWST were designed with the consideration that it'd be mass produced, it would not be the JWST we know today and instead would be a completely different design (a rough comparison can be between On…

Another JWST would have cost 1 Billion, so it is more than an Order of magnitude less.

Re: A rocket a day keeps the high costs away (1993)

#88

Post by bryanlarsen »

tsimionescu wrote: post #82
bryanlarsen wrote: post #41

Earlier quoted context omitted.

Starship has the size to carry about 400 passengers. Both stages together carry about 5,000t of propellant. But over 3/4 of that is liquid oxygen, and most of that is the first stage. The second stage alone with 1200t of propellant can't put humans into orbit, but it does have a range comparable to that of a 787. So 300t of liquid methane will get 400 passengers about as far as a 787 can get 250 passengers with 100t…

Starship has nowhere near the capacity to carry 400 passengers - people are not sardines you can just stuff into the rocket like you can satellites. You need plenty of equipment per person for manned spaceflight. Much more so if you want to compete with business class flying. Also, the total travel time would be horrible, since you can't have a rocket launch/landing facility anywhere near a city, and loading and unlo…

It's not as if 40,000 feet is survivable without a flight suit and parachute, yet airliners don't provide those. And 400 people per starship is much more spacious than the area you get in economy class.

Travel time is the main reason to use Starship. It might add 30 minutes extra on either end, but if it saves 10 hours of flight tine...

Loading people into an already fueled rocket is standard operating procedure for every rocket except Falcon.

Re: A rocket a day keeps the high costs away (1993)

#89

Post by jessriedel »

tsimionescu wrote: post #80
jessriedel wrote: post #74

Earlier quoted context omitted.

The issue you're point out is real, but keep in mind the global tourism industry is ~$8 trillion, out of a total world GDP of $100 trillion. $1T per year on space tourism is possible.

If you were to limit tourism to those fit enough to be allowed anywhere near a space launch, do you still think you'd reach that number? Not to mention, space tourism being an eighth of the total tourism market is obviously insane. The total tourism market is gigantic, space tourism would do wonderfully if it it were 0.01% of it (so, 8 billion or so? Probably not enough to warrant an assembly-line approach).

> If you were to limit tourism to those fit enough to be allowed anywhere near a space launch, do you still think you'd reach that number?

Yes. The majority of the population can handle 3Gs. John Glenn was 77.

> Not to mention, space tourism being an eighth of the total tourism market is obviously insane.

I don't think space tourism becoming an eighth of total tourism is insane. I'd guess the fraction of tourism dollars that are spent on travel reached by plane is a lot higher, maybe about a third or half.

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