No, Futurism:
All that essential, but not actually useful, extra weight jacks up the cost of a mission. Falcon Heavy launches cost $1.2 million USD per ton of payload. Again, that’s a crazy improvement from earlier missions, but that many zeros on a space mission mean these launches will stay out-of-reach for consumers or smaller companies.
No one outside of SpaceX knows what Falcon Heavy costs (and that depends on whether you mean average cost or marginal cost).
And then there is the environmental cost. These souped-up rockets use more fuel, and Falcon rockets rely on what’s basically kerosene and oxygen. Per launch, the carbon these missions spew isn’t that much. But if space flight frequency reaches the twice a month threshold that SpaceX is aiming for, experts think the overall carbon output could reach 4,400 tons a year. If every private space company chimes in with their own launch emissions, that number could climb dramatically.
Not everyone uses kerosene. Blue Origin (and ULA) plan to use liquid natural gas (mostly methane), which has much lower carbon content. And they both plan LOX/LH2 upper stages, whose exhaust is water. And even at a hundred times that amount, it would continue to be dwarfed by the airline industry.
There are also all the potential atmospheric impacts that we don’t understand very well. Burning rocket fuel emits soot and a chemical called alumina, and scientists have started to study how these molecules break down our ozone layer, something we’ve been working hard to restore over several decades.
Again, not all rocket fuel. Methane will produce almost no soot, and hydrogen none. And only solid rockets emit alumina, and only ULA plans to use them (OK, well, NASA will have them on SLS, if it ever flies, but it will hardly ever fly).
No, it will be a long time, if ever, before we need space elevators, even if they’re technical feasible and practical.
Futurism, indeed.
A space elevator has absolutely no hope of being built unless rockets manage to expand the launch market by many orders of magnitude over the current market.
It took centuries of ships rounding Cape Horn before the Panama canal became economically attractive.
All these big infrastructure projects (propellant depots, lunar propellant, Mars cyclers, etc) suffer from the same problem to greater or lessor degrees.
There’s already a propellant depot on orbit. Two if you count Tianzhou 1 demo.
Socialist countries, before they collapse, anyway, like to build big important stuff to impress the serfs with the power of the state. A space elevator would be just the ticket. Paid for by carbon credits, perhaps.
Oh great. Something else for the Elon Musk haters to latch onto. ?
CO2 is not a showstopper for rockets, since it can be removed from the atmosphere elsewhere.
The ultimate limit is likely to be set by hydrogen, not carbon. That’s because the stratosphere, where much of the hydrogen (unburned and as water) ends up, is naturally extremely dry. I think the limit would be around 1 million Starship launches per year.
Carbon is irrelevent, so reducing it is an unserious concern.
Carbon is exceedingly relevant. It’s a precious fuel for future tax increases based on it’s use. Those taxes will go for important things like the SLS.
SpaceX price is everyone else cost.
Certain words are in the lexicon of unserious people.
spew
cherry pick
sustainable
There are others — help me out, here.
morally serious
representation
empowering
media center (instead of library)
Toxins. Cleansing. Traditional medicines. Holistic. Carbon-neutral. Most nouns with “green” as a modifier. Denier. Most nouns with “public” or “social” as a modifier. Most phrases with “Studies” as a noun and some capitalized adjective in front of it.
Justifications appealing to the good of a sector of the populace (particularly of the children) [I know that’s more than one word].
We all gonna die (and variations of we all gonna die)
Problematic
Problematic
Concerning
Thanks for making me laugh today Rand. This article is a recycle of previous articles on the subject. ( hehehe..get it? recycle!)
Anyways, a near verbatim version is here:
https://www.theverge.com/2018/5/31/17287062/rocket-emissions-black-carbon-alumina-particles-ozone-layer-stratosphere
And just for kicks I followed the link to the articles sponsor, the “Skyway Group”, and I swear the jokes are writing themselves, but they are pushing the construction of what are basically monorails.
http://rsw-systems.com/?lang=en
https://www.youtube.com/watch?v=ZDOI0cq6GZM
Gee, an elevated cradle circling the earth at the equator, holding an expanding (but also evacuated) tube that has to contain millions of tons of metal traveling in excess of LEO orbital velocity.
And worries over the environmental impact of rocket exhaust is their reason for doing this? Wow. Just, wow.
But the equator is a long ways away from the east and west coast of the USA.
The question I’ve always asked myself, especially now that it turns out reusable rocket ships are plausible, is: what do big infrastructure systems such as space elevators, cyclers, and momentum transfer tethers bring to the table? Not a lot. And lets look to the past for a clue. The 19th century saw the rise of steamships, not a transatlantic tunnel (Harry Harrison not withstanding).
It is always necessary to be careful with analogies. The 19th also saw the rise of railroads. Specifics are important. Railroads and steamships did not span continents and oceans in the 18th because the technology wasn’t there. Just as trucks and aircraft ate into the transportation market share in the 20th. Pipelines are another data point.
The past is informative. It is not a blueprint.
Yes, we do have to be careful with analogies, and one of the things we have to be most careful about is nitpick analogies by using oversimplified history. For example, steam railroads came into being because railroads already existed for steam locomotives to use, not the other way around. Similarly, though practical commerical steam engines that could have been adapted for maritime use existed for much of the 18th century. Steamships waited until steam engines were overwhelmingly better than sail.
This points up the most interesting analogy of all: each major transporation revolution had a 50 year period of “hanging fire,” not taking off until the new technology was overwhelmingly better than what went before. This is true for steam (both rail and shipping), air travel (dirigible airships could have been built in the 1860s, using a technology demonstrated in the 1850s), and space travel? Well, we went to the Moon in 1969, and 50 years later it’s time for SpaceX Starship?
The past IS informative, but declaring it “not a blueprint” runs the risk you’ll miss the lessons of the past.
The first use of steam to power transport was in fact in riverboats. Rail came later. It just took decades longer to migrate it into ocean-going vessels.
One of my favorite ship names came from an early Newcomen engine riverboat operating in France: “Pyroscaphe.”
Another point from rail is that infrastructure projects usually followed after a significant number of people were already going there. We didn’t build a transcontinental railroad until after a lot of people went west by wagon train. Right now jumping into any large scale alternative launch idea is about like wanting to build the transcontinental railway when most of the people heading west were trappers.
Different space missions require different orbits. At first glance, a space elevator would only be good for putting satellites into GEO. Perhaps if you used one to deliver (and refuel) a powerful space tug, you could deliver satellites into other orbits. However, I don’t see that as a practical or efficent way to put satellites into a sun synchronous or similar high inclination LEO.
One of the important things about the SpaceX Starship (including it’s more nameless Super Heavy booster) is that it can reach all contemporary orbits from any launch pad, without flying a dogleg. Let’s say that’s Boca Chica, which can only fly out on two over-sea azimuths, threading either the Florid Strait or the Yucatan Strait. Doing so, it can put 100 metric tons in LEO. But we have to realize that can be any combination of actual payload and residual fuel. Suppose it’s a 6 ton comsat and 94 tons of fuel? It could put the satellite in GTO and return to Earth with ease. In fact, by using super-synchronous plane changing, there’s no orbit it can’t reach, and then land on Earth afterwards. To reach BEO orbits and land on planets and asteroids requires refueling, who planned infrastructure is simply tankers. Orbital fuel depots can wait until the flight rate justifies it. I wonder what flight rate would justify space elevators?
Depends on what heavenly body we are talking about? I’m not sure a space elevator makes sense for Earth but there are compelling cases for other locations.
SpaceX is building a tanker but if there were other customers, couldn’t it act as a fuel depot? Its just a depot that can go up, down, or someplace else. SpaceX needs so many tanker launches to support a trip to Mars but maybe someone else just wants to buy a partial load for their own trip to somewhere. It depends on how long a SpaceX tanker can stay in space, how they will store the fuel, and if how they plan to transfer fuel will work with other vehicles.
Does ACES or any other depot proposal have as much storage capacity as a SpaceX tanker?
I think the only depot worth looking at at this point is the Resource Depot Hercules proposed by Bigelow. In the current hypothetical version it’d be 8300 cubic meters volume. I think that might be around 30-40 Starship-tanker loads, so maybe enough to completely refuel a 5-6 ship Mars-bound squadron. Also useful for something like an ACES-70 tug operating throughout cislunar space. Various proposals show these with a crew cabin.
With a space elevator, there are no other orbits out to the upper end of the elevator (at least without dynamic control enforcing a resonant orbit (even comsats have to do station-keeping)).