Monthly Archives: September 2014

65th International Astronautical Congress gets underway

The International Astronautical Foundation is hosting its 65th International Astronautical Congress in Toronto, Canada, from September 29th through October 3rd at the Metro Toronto Convention Center.

The Space Elevator, and progress towards building it, will be well represented during this Conference. Dr. Peter Swan, the President of ISEC, will be giving a couple of presentations and Stephen Cohen, Technical Editor of Volume 3 of CLIMB, the Space Elevator Journal will also be presenting.

A new look!

I haven’t updated the “look-and-feel” of this website in, well, forever.  I’m a guy who always recommends to my friends that they keep their software up-to-date, but I guess I’m also like the carpenter and his own home…

Anyway, we’re now on WordPress 4.0, the current version, and have a new theme for the site.  I tried many of the ones out there (both free and for-fee), but wound up using the 2012 theme packaged with WordPress.  Clean, simple, neat, just the way I like it.  And the masthead, designed by Susan Seichrist, which looked really great with the old site theme, looks absolutely awesome (IMHO) with this new site theme (Thanks again Susan!).  The old site was a bit too condensed and this one is much more ‘airy’, maybe even too much.  I might be slightly modifying some of the .css over the next few weeks as I get more used to this new theme.  Or maybe not 🙂

I still have a few minor tweaks to do; conference pictures from this year are not yet appearing (those pesky spaces in file names) and several posts can now be made to ‘look better’ with the new theme.

Anyway, hope you like it – and now back to posting – I have a lot of new items for everyone!

A new space elevator documentary needs your help!

A new space elevator documentary is being created and it needs your help!  The good folks over at Going Up! Films have been following all of the efforts in the space elevator arena for the past several years, interviewing and filming, and they are now ready to finalize the documentary film they are creating.

They have started a Kickstarter campaign and we need everyone who is interested in the space elevator (or just cool projects in general) to participate and DONATE!

The film is to be called “Sky Line: The Space Elevator Documentary” and will cover (in their words):

“For the past several years, the SKY LINE team has been following the space elevator community as they pursue a seemingly impossible vision. From attending various scientific gatherings, to covering NASA’s high-stakes Space Elevator Games, we got to know the major players and watch their successes and struggles, both personal and professional.  As we wrap up filming and head into post-production, we’re asking for your help with finishing funds, so we can bring this fascinating story to life.”

If you support the idea of a Space Elevator, if you want to help get the word out to everyone, please DONATE and support this project.  I have and I hope you will too.

Visit their Kickstarter website to donate and to see the (very cool) trailer…

NASA Spinoffs

While this topic is not directly related to a space-elevator, I thought you would find it as interesting as I did.  And, with the recent news that NASA has chosen Boeing and SpaceX to ferry astronauts to/from the Space Station, it’s pretty timely.

Krista Coleman sent me a link to an infographic, a portion reproduced below, detailing some of the spinoffs that have been created due to NASA’s efforts over the past several decades.  Some I already knew, some were surprises to me.

Who knew that we could blame NASA for selfies!

To see the entire infographic, click here.

Thanks Krista!

The Space Elevator appears in the NSS Ad Astra magazine

In the Fall, 2014 issue of the National Space Society’s Ad Astra magazine, there is a four page article on the Space Elevator.

Unlocking the potential of space elevators is a four page article, written by Peter Swan (president of ISEC) and Cathy Swan, that referenced and summarized the recent IAA study on Space Elevators.  The whole article (which you can read here) is very good, but for me, the “money quote” was:

“The mission [for space business] for success is simple: Reduce the price for access to GEO to $500/kg while changing the model to: daily, routine, smooth-riding, less dangerous, environmentally sound, open size/mass criteria and mission enabling.”

Indeed…

GEO, the SE center of mass and tether taper…

One of the items which popped up in my FeedDemon Reader a while ago was a Blog post from a group called Sustainable Nano. They are: “The Center for Sustainable Nanotechnology is an initiative funded by the National Science Foundation to carry out research that will enable the development of sustainable, societally beneficial nanotechnologies. We are a group of well-connected but geographically diffuse scientists—at the University of Wisconsin-Madison (Hamers & Pedersen groups), University of Wisconsin-Milwaukee (Klaper group), the University of Minnesota (Haynes group), the University of Illinois at Urbana-Champaign (Murphy group), Northwestern University (Geiger group), and the Pacific Northwest National Laboratory (Orr).” It’s a neat website with plenty of interesting posts – I do like poking around in it.

Anyway to the post in question: “Space Elevator: A Lasting Dream for a Sky-reaching Tree“. The post describes the basics of the space elevator and how a product like carbon nanotubes, one of their group’s focus, could make it all possible. Pretty standard stuff, but the graphics are worth commenting on…

The first graphic shows how a space elevator is “held up” by using the comparison to holding a stick with a rope attached to it and, the other end of the rope attached to some sort of counterweight. Spin the rope about your head (or, in the post’s example, spin your entire body) and, if you’re going fast enough, the rope will stick out straight from you towards the counterweight simulating the appearance of a space elevator. This is a common enough analogy, but does have its flaws. A space elevator is held up by balancing the forces of gravity and centrifugal force but this analogy is only demonstrating the centrifugal force portion. You (or the stick) have taken the place of gravity by holding the “earth-end” of the tether and keeping the counterweight from flying away. But I can’t think of a better way to demonstrate it and it does have the advantage of quickly being able to demonstrate the basic idea. In the graphic though, it shows Geostationary orbit (GEO) much closer to the counterweight than to the earth and the center of mass of the system at GEO (that’s where the arrows in the graphic seem to be pointing to). Using the standard Edwards/Westling model, the elevator tether is 100,000 km long while GEO is approximately 35,700 km above the surface, i.e. much closer to earth than to the counterweight at the end of the tether. Regarding the location of the center of mass of the system, it needs to be above GEO.  I, myself, used to erroneously think that the center of mass would be at GEO and have visited this topic before. Dr. Blaise Gassend wrote up a simple explanation of why the center of mass has to be ABOVE geosynchronous (geostationary – GEO) orbit.

The second graphic, the one referring to the almost-certainly necessary taper of the elevator tether is one that I’ve seen in similar format several times before. I’ve wanted to address it before, but just haven’t – I’ve been too lazy to try and draw my own version of the “correct” ratios for a tethered taper (I’m just familiar enough with Photoshop to be dangerous…). You’ll note that the blog post shows the tether increasing from a point at the earths surface to something much wider at GEO and then reducing back to a point at the counterweight. Ignoring the location of GEO (the same as in the first graphic), the idea of the tether widening from the earth to GEO and then narrowing from GEO to the counterweight is correct. But the ratio is wrong:

Creating my own model took me a lot longer than I had first thought – I redid it a half-dozen times before I had something I thought was worthwhile. Of course it’s not to scale either, but the ratio of the taper width at the earth’s surface (13.52) to its width at GEO (35.44) to its width at the counterweight (23.88) is correct. Also, given the shown length of the tether, the location of GEO is correct. The graphic is greatly “squooshed” of course, being much shorter than a real tether in this scale (by several orders of magnitude). But the difference between the length and the width of the tether demands this type of alteration.

One other thought; I think when most people look at drawings of tether taper, they assume that it’s the width of the tether which must alter. That’s not necessarily the case. It can also be the thickness and that, I think, would have advantages. If the width of the tether was constant (once you’re above the atmosphere – in the atmosphere it may well be a cable), then you don’t have to design a climber which can accommodate varying widths; much easier, I think to design a climber for a tether with a varying thickness. But then again, maybe it will be something like a Hoytether.

Anyway, enough. Where did I get my numbers? They came from the most excellent spreadsheet developed by long time friend of the space elevator Maurice Franklin and which you can find by clicking on its page link at the top of blog (The SE Analysis Spreadsheet). I’ve blogged about this before, and I’d like to encourage readers to play around with it – when you do, you really begin to get a feel for the physical constraints that engineers and scientists have to deal with in the real world. I used his Edwards/Westling Baseline model with no changes.

Dr. Brad Edwards at ideacity

Some months ago, Dr. Brad Edwards made an appearance at the ideacity forum in Toronto and gave a talk on Space Elevators.  You can view the video here – it’s not long, less than 20 minutes.  I always enjoy hearing Dr. Edwards speak about the Space Elevator, but I do have a couple of issues with his presentation.

To listen to the talk, one would think that the idea of a Space Elevator was first explored in science fiction.  He did not mention either Yuri Artsutanov or Jerome Pearson, the first engineers who came up with the modern-day idea of a Space Elevator and who, in the vernacular of the field, “ran the numbers” (especially Jerome Pearson).  Both of them did so long before Sir Arthur C. Clarke popularized the idea in his book The Fountains of Paradise (both authors, by the way, corresponded with Sir Arthur about space elevators).  There can be no disputing Dr. Edwards contribution towards the effort to build a Space Elevator; he (and Eric Westling) wrote THE book on space elevators, but he wasn’t the first person to describe what a real space elevator might look like.

According to his talk, we now have the carbon nanotubes necessary to build a space elevator.  Oh, if only that were true. I wish, I wish, I wish…  Yes, there have been carbon nanotubes built which are 55 cm long and yes, there have been carbon nanotubes which have tested out at 200 GPa, but not at the same time.  And, even if you can get CNTs to grow to this length and have perfect (no defects) structure, they’re still not going be aligned – and alignment is key to making threads of macro-strength.  I do agree that we’re getting closer, but I don’t think we’re all that close yet.  Spinning CNTs into threads is a whole different kettle of fish than spinning normal animal or plant fibers into threads.

And finally, let’s talk about my “favorite” subject, space-based solar power (SBSP).  I’m already on record as being very skeptical (to say the least) about SBSP being able to provide power except under unique, niche circumstances.  Dr. Edwards talked about the Obayashi project to build a space elevator and provide SBSP for Japan.  Let’s run the numbers for “just” Japan.  The most current electric generating capacity I could find for Japan was for 287,000,000 kW (for 2013).  Energy available at earth’s orbit is 1.3kW/m2.  What efficiency number should we use?  Let’s say 40%.  I think that’s generous.  Yes, I know there are cells out there which are slightly more efficient, but they are expensive and, when you see how much we’re going to need, I think that cost economy will play a role here.  So, to generate 287,000,000 kW will require about 440,000,000 m2 of solar cells (or 440 km2).  This is roughly equivalent to the land area of the Seychelles or of New Orleans.  How much mass?  If you figure 5 kW / kg (see the Space Elevator Feasibility Condition for details), you come up with 57,400,000 kg (or 57,400 metric tons).  Now that’s just for the cells themselves.  There will also need to be a massive structure holding them together, an enormous amount of cables, antennas to beam the power to earth and also some sort of propulsion / steering system (along with the propulsion mass) so that you can keep the collection array pointed at the sun and the transmission array pointed at Japan.  The best I can do here is a guesstimate – 50% more for the ancillary mass?  I think that’s probably ballpark.  So, a total mass of about 86,000 metric tons.  If you have an elevator that lifts 100 tons to GEO every week, then it’s going to take you 860 weeks (16&1/2 years) to just lift the mass up there.  Then you have to either lift personnel to put it together and maintain it or else robots to perform the same.  You’ll need to periodically replace the panels due to space debris and other space-related hazards and you’ll need to replace the propellant too.  And that’s assuming everything goes right.  Things always go wrong, so you’ll need to deal with that too.

Add that all up and you can see why I’m skeptical about this.  Now, if you wanted to replace “just” the nuclear generating capacity of Japan with SBSP…  Nuclear plants provide about 18% (roughly 1/5th) of Japan’s electric power – at least they did when they were all online.  So if you wanted replace just the nuclear power generating ability with SBSP, well, then, maybe…  Maybe that is a possibility, with an engineering project dwarfing anything else created by human beings.

Color me skeptical, very very skeptical…

One final note; Dr. Edwards talks about his company – I’m assuming he’s referring to this.

The cost of living on the Moon (and Mars!)

Several weeks ago, I was contacted by the people at NeomamStudios, telling me about a graphic they had put together showing the total cost of living on the Moon.  This was part of the 45th Moon Landing Anniversary Celebration and is, I think, of interest to people who support the idea of a Space Elevator.

If you are like me, and believe that the major (or at least “a” major) use of the Space Elevator is to help us colonize the solar system and, to paraphrase Robert Heinlein, get some of our eggs out of earth’s “basket”, then numbers like this are what we need to make our case.  It will be very, very, very, very expensive to create and support a lunar colony using traditional rocket technology, there’s just no getting around it.  A space elevator is the only feasible way to do something like this.

I could have reproduced the entire graphic here, but it’s quite large and I’d rather link to one which is already out there.  I went to the Neomam web site and the graphic is there, so I’ve linked to it and reproduced just a portion of it here.  And, lo and behold, when I went to their website, I found they had also created a graphic showing numbers for the living costs on Mars.  I’ve also reproduced a portion of that graphic here and clicking on either one of them will take you to the Neoman website where you can see the full graphics.

Fun facts from the graphics:

  • On Mars, it would cost $37,244 to watch Psy’s Gangnam Style in HD on YouTube.
  • On the Moon, downloading “Fly me to the Moon” would cost about 12.8 cents.

CNBC visits the idea of a Space Elevator

CNBC’s John Schoen wrote an article about the Space Elevator, releasing it just before the recent Space Elevator Conference and I am just getting ’round now to linking to it…

In addition to writing about Space Elevators, John also discusses flying cars and freight drones. ISEC‘s Peter Swan is quoted in the story.

There are also, unfortunately, the usual inane comments about space elevators in the article’s Comments section.  I tried to correct a couple of the worst, but it’s like trying to drain a lake with a spoon 🙁