tag:blogger.com,1999:blog-8150340806781551727.post7222534208517838095..comments2024-03-28T16:08:53.493+00:00Comments on ToughSF: Boosted Orbital Tether - a fishing line in space!Matter Beamhttp://www.blogger.com/profile/16721504049578296529noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-8150340806781551727.post-55450280011390697862021-10-15T16:10:11.633+01:002021-10-15T16:10:11.633+01:00I don't see the point in the interplanetary ve...I don't see the point in the interplanetary version. Once you are in orbit you can use electric propulsion yourself. There is usually no need for very high accelerations.<br /><br />Launch definitely requires accelerations higher than 1G.OREN Thttps://www.blogger.com/profile/06854541971430934278noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-75249893981149515602017-10-16T01:40:39.457+01:002017-10-16T01:40:39.457+01:00Is this significantly different from the version o...Is this significantly different from the version of your proposal that you discussed on Stardestroyer.net, and if so, how? I recently read over that discussion and wanted to see how the concept evolved from its less viable early iterations into this.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-83715244247187971482017-03-17T17:16:42.273+00:002017-03-17T17:16:42.273+00:00I will explore the concept of exponential growth i...I will explore the concept of exponential growth in a future post.Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-49300328645146753152017-03-17T17:16:23.247+00:002017-03-17T17:16:23.247+00:00I think the formatting messed up your reply. Try p...I think the formatting messed up your reply. Try posting it again.Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-31625677042264012402017-03-17T16:20:47.017+00:002017-03-17T16:20:47.017+00:00This comment has been removed by the author.tonyonhttps://www.blogger.com/profile/08253501266473243514noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-75293738085025783952017-01-30T12:00:07.422+00:002017-01-30T12:00:07.422+00:00I think I read that the 3G figure is for the astro...I think I read that the 3G figure is for the astronauts to be able to work, as in, react to an emergency and push buttons.<br /><br />I agree, the FEEP is not a realistic engine that would be placed on the BOT. <br /><br />However, the concerns over the thruster design are a bit of a moot point once we consider the flywheel kinetic energy sink in the next post, or all the considerations I wrote on this thread: http://bbs.stardestroyer.net/viewtopic.php?f=5&t=166030Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-36677999600770983632017-01-28T18:45:46.721+00:002017-01-28T18:45:46.721+00:002.5min at 5g is pretty harsh, even for the most fi...2.5min at 5g is pretty harsh, even for the most fit astronauts. IIRC, current NASA standards suggest a maximum of 3g, and a preference for just over 2g for continuous durations over a minute or so.<br /><br />Also, I believe their is a problem with your calculations for thruster performance. You appear to be using FEEP as your reference (VASIMR would be a much better performer, IMHO), which can obtain (at least in theory) up to 10 000s Isp; however, its thrust is limited to the μN - mN range. 8kN is out of the question with any existing SEP system.<br />BTW: the theoretical models for VASIMR (which have proven to be well below actual performance obtained, so far) suggest that MW class thrusters will have an Isp approaching 50 000s, and thrust in the tens of Newton range. To date, with 200kW, it has already attained an Isp of 5000s at a thrust of 6N. Even better performance has actually been achieved, boosting the engine to 25% above its rating (250kW).Anonymoushttps://www.blogger.com/profile/08104586551355707368noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-21750527527883581532017-01-25T13:37:16.855+00:002017-01-25T13:37:16.855+00:00Thank you for showing interest!
I hadn't thou...Thank you for showing interest!<br /><br />I hadn't thought of combining it with the Spacecoach concept. I'm guessing the interplanetary version of the BOT is basically a reverse Spacecoach doing reckless things. <br /><br />There's a very interesting discussion happening on G+ right now. I might have to make a follow-up post to expose some of the excellent ideas being voiced.<br /><br />For example: a tether attached to a drum with brakes and a geared flywheel to minimize braking requirements, a flying runway using reverse-thrusting aerocups and even an orbital loop-de-loop.Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-6839365275967538912017-01-25T01:29:05.948+00:002017-01-25T01:29:05.948+00:00It is always interesting to see new concepts (or v...It is always interesting to see new concepts (or variations of older concepts) that are relatively elegant and have the potential for bringing costs down. When I thought of the "Spacecoach" concept, the main sticking point is the vast amount of water needed to provide all the functions of radiation shielding, temperature buffer, life support (etc.) before finally being fed into the engine for thrust. Early spacecoaches would need a "Sea Dragon" sized rocket to loft the water into LEO just for the initial fill up.<br /><br />Tethers would provide a synergistic approach, the empty "Spacecoach" can be assembled in orbit, but water for the initial fill up comes in smaller packages. Even the fully filled "Spacecoach" can be sent on its way using the tether, providing a much greater initial boost than the solar powered ion or plasma drive engines could possibly achieve (and incoming "Spacecoaches" provide the momentum to lift the tether back into higher orbits).<br /><br />Win/win for both systems.Thucydideshttps://www.blogger.com/profile/09828932214842106266noreply@blogger.com