Over at SpaceFellowship.com, they have just posted an interview with Elon Musk, he of SpaceX fame (as well as PayPal, Tesla Motors and SolarCity). The interview covered many subjects. including the Space Elevator. He’s not a fan.
“Question: I know that SpaceX has plenty on its plate right now. However, any thoughts on using your techology after you go public on the construction of a Space Elevator? Private or Public?
Elon Musk: It will be a *long* time, if ever, before the economics of a space elevators make sense. Consider that no one has decided to build a bridge from New York to London and that would be way easier than building a space elevator.”
That’s an odd answer, to say the least. Why would anyone want to build a bridge from New York to London? We already have commercial shipping and air transport that gets things to/from one side of the pond to the other. He really thinks we should drive between New York and London? Rest stops? Gasoline stations? Restaurants? In the middle of the Atlantic? When someone can fly from New York to London in just a few hours? I think he’s totally missing the point, especially considering a quote a little later on in the interview:
“Question: Do you have an estimate of when the common person will be able to take advantage of the fruits of the SpaceX program?
Elon Musk: Depends on how common. If we can make reusability work well, I think we can get the cost per person to orbit down to a few million dollars within eight to ten years. If reusability works well and demand is strong, so that we can distribute overhead over a large number of launches, it could one day get to under $1M.”
“Under $1M“. Gee, how exciting… 🙁
On the other hand, I do tend to agree with his assessment of Space Solar Power:
“Question: Should not NASA be funding research to make Space Solar Power possible in this time of energy crisis as they did in the 1970’s?
Elon Musk: No, I don’t believe in space solar power. It will never be competitive with ground solar power. The cost of converting the electron energy to photon energy and then back again on the ground overwhelms the 2X increase in solar incidence. And that’s before you consider the cost of transporting the solar panels and converters to orbit!”
It’s a very interesting interview – check it out.
(Picture of Elon Musk and the Falcon2 from here. Click on it for a larger version.)
You’re right about the “bridge to London” comment being dumb. The space elevator would be the equivalent of commercial shipping – heavy freight, moved slowly (compared to rockets/jets).
“Under $1M” is quite an improvement.
I agree that <$1M is quite an improvement over what we have today, but it's at least an order of magnitude higher than what one could expect to pay to get to space via Space Elevator.
Interesting, I guess no-one can understand everything. His London-New York bridge analogy is weird, its wrong in just about every way. Odd about the SPSS number too — the SPSS enthusiasts claim the figure is 9x not 2x and microwave beaming is supposedly rather efficient. But I don’t know much about it.
🙂
btw I think this reinforces my contention that talking about cost with respect to the SE is folly. Scalability and reliability are much better selling points.
Ted, you’ve seen my talks before, so please let me know if I haven’t been clear. But here it is again: just because economies of scale suggest you *could* get costs down doesn’t mean that they will come down. Airplane flights cost ~3x their energy cost. Why do rocket launches cost 20,000x their energy cost??
If there were a market for launching 20x as much to orbit as we do now, I’m sure rocket prices would come down. Those who say the SE will lower prices are doing so based upon an assumption of a larger market than currently exists. No one knows what any SE (if/when it could be built) would really cost, so it distresses me to hear so many people claim that it would “of course” bring prices down to a few hundred $/lb at most.
Pardon my asking a some basic questions. Even though I have followed the space elevator concept for about 30 years, certain things do not yet make sense.
1. Rockets today get to LEO in about 10 minutes. Then an apogee kick motor sends them up to GEO in about 8 hours, right? At that point you have to fire thrusters again to circularize your orbit. By contrast, a space elevator that perhaps might travel 500 mph (hard to conceive if any part of the platform is in contact with a cable), it’s still about 45 hrs to GEO. In the lower atmosphere, the platform would probably have to stick to no more than 100 mph to account for drag, so its about 2 hours to LEO versus 10 minutes for a rocket. In each case, I think that if people are involved, what are the human factors where exposure to radiation and just plain boredom come into play. I can keep from going to a bathroom for 1-2 hours, but not for 45 hours. Therefore would a space elevator need elaborate cruise ship like accommodations (and a huge increase in weight)?
2. Other than dragging a spacecraft out of the Earth’s atmosphere to save on the launch fuel, how would this benefit satellite launches? For example, say you want to drop off a satellite in LEO. The tether is moving at a much slower speed than the velocity needed to circularize at that orbit. You would still need to have fuel on board to speed up and achieve a stable orbital speed, right?
3. Elon Musk’s comments about a bridge from London to New York are valid. For example, it is not even clear than the Chunnel is economically valid – it’s more of a convenience. If I can ship a 747 full of freight across the Atlantic in 6 hours, that represents a value that can be reflected in the sale price. We don’t have a transatlantic bridge because slow-moving barges are much more economical and flexible. If you need stuff there quicker (e.g., people), then you just fly. Similarly, satellite companies would rather get to GEO in 8 hours, get the solar panels unfurled (running on batteries is very risky) and prepare the craft for use. I don’t see enough demand for getting to any specific orbit altitude that would justify the expense as a freight hauler. As I said above, only at GEO can you just float around in the same orbit with the elevator terminal.
4. I wonder if the solar power satellite and space elevator have a symbiotic relationship like the Space Shuttle and the Space Station. We need the Shuttle to build the Station, and vice-versa. Instead of beaming massive amounts of microwaves down to the ground (I’d hate to be a plane or bird flying through that beam), isn’t it true that recent improvements in solar cell technology make it better to just carpet the dry deserts with solar collectors? It seems some of the poorest countries have the most sunshine and therefore could benefit more from such an arrangement.
5. Why doesn’t anyone even mention the east or west coast of South America as an anchor for the space elevator? The west coast of South America has very nice weather most of the time and it’s very close to the Panama Canal.
6. Overall, I think a space elevator would be cool – just read Kim Stanley Robinson’s Red Mars series. By the way, a space elevator for Mars might make sense because we currently cannot land anything on Mars much larger than the Mars rovers because the atmosphere is so thin that you cannot slow a large object down quickly enough with parachutes before hitting the ground. This is a huge technical challenge that NASA has not even addressed for manned missions to Mars – without massive retrorockets (and very high G’s) it’s beyond our capability at present.
Hello Steve,
Let me try and answer your questions.
1) Yes, radiation will be an issue, as well as passenger necessities. You need to address the radiation with some sort of shielding (which will increase weight) and you will need to address passenger necessities with either supplies/facilities and or with way-stations. This is why early space elevators will almost certainly concentrate on carrying freight to orbit(s), not people. Rockets will still be needed for people for some years, until you can build a Space Elevator which will carry hundreds of tons. A larger Space Elevator like this is not something which can’t be done; when it’s built it will be even more stable than a smaller one, but the first ones will be smaller as engineering issues will be easier to deal with. Once you do have the larger Elevators, however, you will be able to carry passengers to/from orbit.
2) Satellites will be greatly benefited by launching with a Space Elevator. Right now they have to be able to handle the “shake, rattle and roll” of rocket launches. This is not necessary on a Space Elevator launch. Plus, you can make a satellite MUCH bigger with a Space Elevator. When you get to the larger projected sizes of a Space Elevator, you’ll be able to haul freight cars full of stuff into orbit. You could launch the entire ISS on a single Climber, for example.
3) “We don’t have a transatlantic bridge because slow-moving barges are much more economical and flexible.” I completely agree. Rocket launches are not more economical, they’re MUCH more expensive. If rocket launches could put an unlimited amount of stuff into orbit for $10-$100 per pound, then there would be much less of a need for a Space Elevator. But they can’t. You need to build a ‘railroad’ (a Space Elevator) to do this. As to demand, I think that once the capacity is there, it will be quickly filled up. Big satellites and space stations, tourism, manufacturing, colonization of other planets etc. will all be facilitated by a high-capacity, low-cost, reliable launch mechanism (i.e. a Space Elevator).
4) I’m no fan of the Space Solar Power concept, as you will see if you do a search for my previous posts on this subject. I think there are tactical uses for it, but for you and me to power our computers and TV’s and refrigerators? NFW. I agree – let’s capture the sun power here on the ground.
5) There have been six places chosen to place a potential Space Elevator. All of them have a combination of low winds, very low storm frequency, and almost non-existent lightning. The ‘favored’ one at this point is in the Pacific, about 1300 miles west of Ecuador. The Edwards/Ragan book gives the details of this.
6) You are quite correct about Mars – it may be the first place a Space Elevator is deployed. The tether doesn’t have to be nearly as strong or as long. The major issue, of course, is getting it to Mars – maybe we’ll have to build it there. Or maybe we’ll build one here first and then use it to ‘throw’ one to Mars. With a large-capacity Space Elevator on earth, you can throw hundreds of tons to Mars on a weekly basis. THAT would allow you to colonize the place in style.
The benefits of a Space Elevator are high-capacity, low-cost and safety. It’s similar to the advantages that a railroad had over covered wagons and it’s why the railroads so quickly replaced them. Once some large Space Elevators are in place, rockets will no longer be needed to get out of earth’s gravity well – they will be used only in space (where they belong 🙂 ). If you have more questions, I highly recommend either the Bradley/Westling or Bradley/Ragan books. They discuss these topics in much more detail.
I hope I’ve answered your questions and THANKS FOR READING!
He says quite clearly that building a space elevator would be more difficult than building a bridge over the Atlantic Ocean from NY to London. Nowhere does he say that it would be a good idea to build this bridge. Why is everybody saying how stupid it is? He only brings it up to say that the elevator would be even harder to make. Read it again.
Is A Space Elevator A possiblity
No one here is in any position to judge what he says to be done. This is the guy that rather than being a loungechair blogger living their life in the virtual world, he’s the guy who is actually doing something in the real world, and he puts his money where his mouth is. “A bridge from New York to London” is as stupid of an idea as a “space elevator.”