26 thoughts on ““Halfway To Anywhere””

  2. Jerry Pournelle talks about it in “A Step Farther Out” I’ll see if I can find out more

  3. April 1974 was the original article. Both going to a writers convention. JP says orbit is halfway to moon. RH responds, no halfway to anywhere. So he must have done the calcs. before then.

  4. JP reports the calcs in the book from JPL source. To earth orbit: 7.6 km/s.

    He then includes a table of various destination which includes solar escape as 8.748 km/s. He says RH was making a top of the head comment that was almost right. So add 1.148 km/s. and you could go to any star in the galaxy (on the ecliptic) but would need 100 km/s to leave the galaxy.

  5. I could swear I read it in a Heinlein book (maybe in a preface or in his nonfiction?), but I have no idea which one and couldn’t find the source after a quick Google search. It might be from a speech or interview, too.

  6. Okay, I found something. It’s a passage from a Pournelle book where he quotes Heinlein as saying that quote to him personally. At least, it is according to the linked website.

  8. Pandora’s Box in “The Worlds of Robert Heinlein” 1966 in which he is updating the predictions in made in 1950 for the year 2000.

  11. This is a completely different quote I turned up while looking around.

    “This is the great day. This is the greatest event in all the history of the human race, up to this time. That is — today is New Year’s Day of the Year One. If we don’t change the calendar, historians will do so. The human race — this is our change, our puberty rite, bar mitzvah, confirmation, from the change of our infancy into adulthood for the human race. And we’re going to go on out, not only to the Moon, to the stars; we’re going to spread. I don’t know that the United States is going to do it; I hope so. I have — I’m an American myself; I want it to be done by us. But in any case, the human race is going to do it, it’s utterly inevitable: we’re going to spread through the entire universe. “ – In a live interview with Walter Cronkite of CBS News, on the day of the first moonwalk (20 July 1969).

  12. Stine’s book “Halfway to Anywhere” claims

    Robert Heinlein was right in 1950: Get to low-Earth orbit, and you’re halfway to anywhere in the solar system.

    But doesn’t give any more specific a citation than that. I couldn’t find such a quote in the 1980 version of Heinlein’s “Where to?”/”Pandora’s Box”, but maybe some of the 1950 text got removed in the update or maybe I was just skimming too fast.

  13. This is probably too much work for something that’s probably not -that- crucial, but Baen Publishing is republishing a litany of Heinlein’s work. There’s probably someone there that has a way of getting in touch with his estate, and they might also have a collection of material readily searchable in their computers.

  14. He was making a good point, and it was worth saying it for effect, but I suspect it’s wrong. Getting to Mercury or some of the inner moons of Jupiter would likely take a lot more delta-V than that.

  15. Getting to Mercury or some of the inner moons of Jupiter would likely take a lot more delta-V than that.

    Depends on how you fly and on how you define “halfway”. I’d always assumed that the quote was pointing out that escape velocity has twice the kinetic energy of orbital velocity, so in the two-body problem getting to orbit takes half the energy of getting to infinity. That (excellent, BTW) Project Rho site points out that if you double the delta-V instead, you go from “orbit around Earth” to “Hohmann with capture to Saturn”. On the other hand, if you’re willing to do time-consuming gravity assists… Cassini made it to Saturn on a shoestring, and the Voyagers basically just needed to reach Jupiter to get from there to solar escape velocity.

  17. I couldn’t find anything definite, but Spacequotations.com said

    Once you get to earth orbit, you’re halfway to anywhere in the solar system.

    — attributed to Robert A. Heinlein by many people (includingNASA’s 2003 Astronaut Fact Book), but source unknown.

    I suppose people have asked this question before.

  18. I should point out that 7.6 km/s. is to a certain orbit. Other orbits would require a higher delta V. So JPs almost, becomes certainly for the solar system and some stars (long journey that.) Excluding a sun flyby at 21.249 or circular capture at over 200 for the suns surface. Anything leaving the ecliptic can easily go over the earth to LEO delta V as well (losing much of the Oort cloud.)

    Still, “earth orbit is halfway to anywhere” captures a certain truth.

  20. Missed others as well (looking in mirror, “good going ken!”) JP has a table on pg. 197 which includes columns for flyby, marginal and circular capture delta V for all the planets (before Pluto was downgraded.)

    The highest flyby is Pluto at 8.363. Mercury is the highest marginal at 11.874 and circular at 13.104. But as others have noted, we can go to all of those for less with gravity assists including Ceres (9.530) and other belt objects.

    So orbit really is halfway to every interesting object on the ecliptic.

  21. Plus once you get to orbit you are able to switch to more efficient propulsion systems like ion, plasma, etc.

  22. Plenty of “interesting” asteroids flyby the Earth at over 10 km/s vrel.. so if you wanted to jump on one in the shortest time possible you might want more delta-v.. of course a lot of interesting asteroids flyby at less than 10km/s too.

  23. Once you’ve seen one near Earth asteroid, or perhaps three (stony, carbonaceous, metallic) you’ve seen them all, at least until they slam into our planet. When that rare even does happen, it’s true but statistically improbably that women and minorities are always the hardest hit.

  24. Plenty of “interesting” asteroids

    …visions of one of the kids taking the family spaceship out on a rock hunt…

  26. I’ll requote my old sci.space.policy post here, for convenience (appended at the end). I have nothing to change in that.

    But there’s another interesting quote from the thread Bob-1 points to, though (I didn’t see it at the time; my comment was crossposted there): From Bill Patterson, who’s forgotten more Heinleiniana than I ever knew, 23 Feb 2006 03:10 GMT “My wetware says it’s a saying G. Harry Stine invented, but it was so good RAH picked it up and spread it around. It’s good to have clever friends.”

    Looking back, and knowing Harry, I would not totally dismiss the possibility that he said it first, Heinlein adopted it, and thirty years later when the question came up, Harry just shrugged and figured, it carries more weight that way, and went with it. Harry always cared about getting the job done far more than he did about getting credit. Plus, I’m sure he would have thought the confusion was amusing, thirty years later when I knew him.

    No way to know for sure at this late date, though, unless Patterson at some point can shed more light on the matter. The witnesses I’ve talked to say it was Heinlein.

    Whoever said it, it’s a great quote!

    HV – 1Aug2011

    Henry Vanderbilt – 22 Feb 2006 18:06 GMT
    The quote is, as best I know, “once you reach low orbit, you’re halfway to anywhere in the Solar System.” The precise wording is not definitive, however, and here’s why: When I was starting up Space Access Society back in ’92-’93, I wanted to use the quote on our logo. I’d been hearing it for years from G.Harry Stine and others, but when I went looking to make sure I got the precise wording right, I could not find the original Heinlein source in print. So I asked G.Harry, and here’s what he told me: He’d heard the quote personally from Heinlein; he’d met Heinlein as a young rocket engineer and space enthusiast who did a bit of SF on the side, and corresponded and/or hung out with him on and off over time, so presumably the technical side of space travel came up in discussion a fair amount. He didn’t know of a place Heinlein had it in print either, but he assured me it was a Heinlein quote, repeated a number of times with minor variations. So I made sure I had a cleanly phrased version for the logo, checked with G.Harry that it sounded about right, and ran with it.

    That’s the story as I know it. I never met Heinlein, but I did and do know a number of people who in turn knew Heinlein over an extended period and talked space with him. There isn’t much doubt in my mind the quote is authentic, but I am a secondary source and couldn’t prove it.

    Pournelle and Niven come to mind as people likely to have heard it from him in person, for what it’s worth.

    Henry Vanderbilt

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