most recent 30 from http://payload42.com 2010-09-10T00:17:50Z http://payload42.com/feeds/user/9 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://payload42.com/questions/70/will-an-object-exiting-the-earths-atmosphere-experience-the-same-thermal-varianc/71#71 Geoffrey Carman 2010-02-05T20:16:41Z 2010-02-05T20:16:41Z

<p>Launch vehicles definitely experiences heating on the way up. </p> <p>What is different is that the high speed portions are in different parts of the atmosphere with differing densities and thus different amounts of friction.</p> <p>Also, the design of reentry vehicles is almost always focused on converting that 'friction' into heat to ditch orbital kinetic energy. Whereas launch vehicles try to minimize that affect.</p>

http://payload42.com/questions/57/what-are-the-essential-space-museum-sites-in-america-to-visit/62#62 Geoffrey Carman 2009-12-22T13:24:01Z 2009-12-22T13:24:01Z

<p>Huntsville Alabama is the only one I have been too.</p> <p>Smithsonian in DC has Apollo 11, Skulab mockup and more.</p> <p>Air and Space museum in Ottawa, Canada has the Apollo 8 capsule I velive.</p> <p>Kennedy/Canaveral is another obvious one.</p>

http://payload42.com/questions/44/are-space-ramjet-engines-plausible/47#47 Geoffrey Carman 2009-11-02T13:22:48Z 2009-11-02T13:22:48Z

<p>Typically a Ramjet, is defined the other way around. Carry and provide the fuel, but use the oxidizer from the atmosphere. I.e. Ram in the oxygen to get the density sufficient, and combust it with fuel you carried along.</p> <p>Nonetheless, it is not very realistic for orbital operations, since on an orbital flight you want to go almost straight up to get out of most of the atmosphere as soon as possible, then tip over once clear, and accelerate to orbital velocity. </p> <p>Thus your time spent in the atmosphere with sufficient oxygen to use as it flows by is minimized. If you want to change that and accelerate to orbital speeds within the atmosphere, you run into heating issues, as you might imagine, and drag issues that usually are considered enough to make this an unsuccessful approach.</p> <p>For missiles and things that stay in the atmosphere, it seems like an interesting idea though.</p>

http://payload42.com/questions/36/falcon-9-first-launch-details-on-the-dragon-model-being-used Geoffrey Carman 2009-10-29T13:24:46Z 2009-10-30T20:36:43Z

<p>Has anyone seen details about the Dragon engineering model that SpaceX intends to use on the first Falcon 9 launch? </p> <p>I am curious if they will include a heat shield and try a controlled reentry. </p> <p>The issue is, if they have no reaction control system, then they probably cannot do a controlled reentry. Same issue if they do not have any of the computers/software on it.</p> <p>Be interesting to see what they intend to launch, in more detail.</p> <p>Here's hoping they can make their window before 2010.</p> <p>Edit: Looks like they will not make it 2009. They seem to be asking for a Feb 2010 launch window now. Oh well. I guess it really is rocket science.</p> <p><a href="http://spacenews.com/launch/requested-falcon-range-date-has-conflict.html" rel="nofollow">http://spacenews.com/launch/requested-falcon-range-date-has-conflict.html</a></p>

http://payload42.com/questions/36/falcon-9-first-launch-details-on-the-dragon-model-being-used/42#42 Geoffrey Carman 2009-10-30T20:36:43Z 2009-10-30T20:36:43Z

<p>This link <a href="http://spacenews.com/launch/requested-falcon-range-date-has-conflict.html" rel="nofollow">http://spacenews.com/launch/requested-falcon-range-date-has-conflict.html</a></p> <p>says: </p> <blockquote> <p>SpaceX said as recently as Oct. 21 that the inaugural Falcon 9 launch is a demonstration flight that will carry a prototype reusable cargo-carrying vehicle being developed with NASA funding help. The mission will provide aerodynamic and performance data on the Dragon capsule qualification unit, although the primary customer for the mission in a U.S. government customer SpaceX says it is not at liberty to name.</p> </blockquote>

http://payload42.com/questions/22/best-space-science-fiction/28#28 Geoffrey Carman 2009-10-25T01:43:47Z 2009-10-25T01:43:47Z

<p>Heinlen is hard to beat, pretty much across the board. Though one could quibble that once he hit the 80's or so the sci fi component went downhill. </p> <p>His juveniles are some of my favorite books I read as a kid (Well that and Dr. Doolitlle and Freddy the Pig Detective).</p> <p>Larry Niven, Ringworld and the Integral Trees are REALLY tough to beat in terms of sheer scope.</p>

http://payload42.com/questions/18/what-podcasts-vidcasts-that-are-space-related-are-out-there Geoffrey Carman 2009-10-22T20:39:22Z 2009-10-24T17:19:39Z

<p>I am sitting and listening to Ken Livingston's Space Show, and it is pretty good.</p> <p>What other ones are out there?</p>

http://payload42.com/questions/14/what-pitfalls-does-spacex-face-that-might-be-avoided Geoffrey Carman 2009-10-20T17:22:58Z 2009-10-21T12:26:35Z

<p>Do you think SpaceX will deliver on Falcon 9, Dragon, manned Dragon, etc?</p> <p>Or do you forsee failure in any particular way? What failiures are there to be concerned about?</p> <p>Falcon 1 took three flights to get right, and well done to the SpaceX team. </p> <p>I happen to be a huge fan, and am betting on success, but I am wondering if people see pitfalls for them, that are worth discussing.</p> <p>(Aside from the usual, its rocket science, its hard!) </p> <p>Edit: So I read the FAQ and realize this as originally phrased was subjective, let me rephrase to make it more appropriate.</p>

http://payload42.com/questions/10/how-is-asteroid-impact-probability-calculated/15#15 Geoffrey Carman 2009-10-21T11:45:28Z 2009-10-21T11:45:28Z

<p>I think the core is issue is the level of uncertainty due to the complex gravitational influences.</p> <p>Its pretty easy to model just say the planets affect on an asteroids object, but there are other sufficiently large bits of mass floating around, that over the course of a multi year orbit have enough affect to matter.</p> <p>I think as computing power gets better, more data is collected on bits of mass floating around out there, the accuracy of the predictions will increase. </p> <p>But I suspect tracking down, and monitoring the orbits of all that mass will be a bigger problem than computing power. (I.e. A cluster of 1024 CPU's (Say 128 1U 2 socket, 4 core servers, like the original SO runs on) these days is actually dirt cheap, compared to what that kind of power used to cost. </p> <p>More directly to your question, I suspect X% chance on something 100 years out is little more than a wild guess. If there were no other influences in the solar system, than we currently know about, then it might start to work. But in 100 years, the little perturbations add up, to make any real estimate little more than guess work (In my mind, at least).</p>

http://payload42.com/questions/9/whats-the-most-valuable-resource-on-the-moon/13#13 Geoffrey Carman 2009-10-20T17:20:14Z 2009-10-20T17:20:14Z

<p>You need to clarify a smidgen more.</p> <p>Useful on the moon for day to day activities, or useful once brought back to earth?</p> <p>On the moon itself, water, silicon, aluminum are all very valuable to build and live off resources.</p> <p>He-3 is probably more useful back on earth than on the moon, assuming it really is there in sufficient and collectible quantities, and we can actually build something to use it effectively.</p>

http://payload42.com/questions/2/what-prizes-are-currently-on-offer-that-incentivize-space-exploration/12#12 Geoffrey Carman 2009-10-20T17:11:43Z 2009-10-20T17:11:43Z

<p>Who is running the:</p> <p>Lunar Regolith Challenge? Powered Beaming Challenge? Tethered Climb Challenge? Glove Challenge?</p> <p>Ok, I looked that is the NASA Centenial Challenges, and those seem to have generated a lot of good stuff!</p> <p>Also DARPA is doing some autonomous driving challenges on Earth that have relevance, to extend the technology to elsewhere.</p>

http://payload42.com/questions/20/what-significant-advances-in-rocketry-have-been-made-in-the-past-40-years/48#48 Geoffrey Carman 2009-11-03T14:24:31Z 2009-11-03T14:24:31Z

Can you cite something that describes the power of the Apollo computer as 486 class? I find that incredibly hard to believe. This is the 1960's that it was designed, and the 486 is actually an astonishingly advanced chip compared to anything before it. Perhaps you mean the Space Shuttle? Even then, that is 1970's tech, and the 486 is 20 years more advanced.

http://payload42.com/questions/44/are-space-ramjet-engines-plausible/46#46 Geoffrey Carman 2009-11-02T13:19:27Z 2009-11-02T13:19:27Z

You of course are thinking of a Bussard Ramjet, the fodder of Larry Niven's Known Universe series. Alas, I recall reading Niven note that it had been proven that the density of hydrogen is too low to support this idea. However, I suspect the original questioner was thinking on the lines of Earth to Orbit rather than interstellar travel.

http://payload42.com/questions/22/best-space-science-fiction/40#40 Geoffrey Carman 2009-10-30T10:15:49Z 2009-10-30T10:15:49Z

You meen the Heechee series? I enjoyed that.

http://payload42.com/questions/18/what-podcasts-vidcasts-that-are-space-related-are-out-there/19#19 Geoffrey Carman 2009-10-23T13:49:42Z 2009-10-23T13:49:42Z

Good one! Thanks! Will keep looking for others.

http://payload42.com/questions/9/whats-the-most-valuable-resource-on-the-moon/13#13 Geoffrey Carman 2009-10-20T17:58:28Z 2009-10-20T17:58:28Z

Thanks for the clarification! Much more clear. Now do you want the single most? Or more of a listing in terms of value?