The American Association for the Advancement of Science (AAAS) has a podcast series they describe as:
Quirky, entertaining and informative, Science Update is a daily, 60-second feature covering the latest discoveries in science, technology and medicine. Produced by AAAS, the world’s largest general science society, Science Update has reported on thousands of scientific and medical breakthroughs—and won dozens of national awards—since its inception in 1988. Science Update even answers listeners’ science questions, phoned in to our toll-free answer line, 1-800-WHY-ISIT (1-800-949-4748), or submitted via our online form on our Contact page. For more in-depth science news, you can also listen to our weekly Science Update Podcast.
I’ve never listened to the podcast before, but an episode released today made me sit up and take notice. A listener asked if it was possible “…to build an elevator up to the International Space Station (ISS)“. According to the podcast’s producer, Bob Hirshon, “NASA…says it’s actually something NASA’s investigating in the form of mechanized compartments that climb a cable into space“. The subject expert Mr. Hirshon was interviewing from NASA was clearly talking about something else (at least I hope she was), making climbers that could crawl up “cable structures“. He ends the program by saying “So some day sending spare parts up to a space station could be simply a matter of pressing the up button.” For a space station located along a space elevator, I would agree. But the listener asked about building an elevator to the ISS. And the answer to that is no. No, no, no, no, no…
The ISS orbits the earth at about 4.8 miles per second. You’re going to build an elevator that somehow attaches to that, or maybe you can “throw” something to the ISS as it whizzes by? I don’t think so. And it gets even more amusing. Imagine an elevator somehow being built “down” from the ISS to the earth. The bottom end would be traveling greater than Mach 21, assuming it’s at the height of the earth’s surface 🙂
Even sending something to the ISS from a true space elevator is not easy. The ISS orbits approximately 205 miles above the earth. At that height, a point on the space elevator would be traveling .3 miles/second. So, if you had an item at that height and wanted to send it to the ISS (traveling at 4.8 miles/second), you’d need rockets to accelerate it into the proper direction at an additional 4.5 miles/second and then there’s all that rendezvous trickiness you have to deal with…
So dear listener, what AAAS should have told you is that, while it may be possible to build an elevator to space when the right material becomes available, it will not be possible to build an elevator to the ISS.