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Open Lines, Tuesday, 10-8-13 October 9, 2013

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Open Lines, Tuesday, 10-8-13

http://archived.thespaceshow.com/shows/2102-BWB-2013-10-08.mp3

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Guest:  Open Lines with Dr. David Livingston.  Topics:  The movie Gravity, NASA budget issues, ISS, Commercial Crew, SLS missions, Orbital, SpaceX and more.  Please direct all comments and questions regarding Space Show programs/guest(s) to the Space Show blog, https://thespaceshow.wordpress.com.  Comments and questions should be relevant to the specific Space Show program. Written Transcripts of Space Show programs are a violation of our copyright and are not permitted without prior written consent, even if for your own use. We do not permit the commercial use of Space Show programs or any part thereof, nor do we permit editing, YouTube clips, or clips placed on other private channels & websites. Space Show programs can be quoted, but the quote must be cited or referenced using the proper citation format. Contact The Space Show for further information. In addition, please remember that your Amazon purchases can help support The Space Show/OGLF. See www.onegiantleapfoundation.org/amazon.htm.

Welcome to our two hour Open Lines discussion program.  For the first hour, our discussion topics included the movie Gravity and its special effects plus as said by many calling and emailing on the topic, “really bad orbital dynamics!”  We had fun talking about Gravity, the cast, the story line, and how Hollywood often gets the science and engineering wrong.  John Hunt also talked about SLS and basic physics, the gravitational constant theory, quantum vacuum thrusters, and he responded to Doug’s question about light, mass, and momentum.  John also addressed issues with the quantum theory.  Dr. Lurio of the Lurio Report was next to phone in after “SLS Man” as he referred to John, cleared the line.  As frequent listeners know, Dr. Lurio and John are on opposite sides of the SLS issue which I guess earned John the title SLS Man.  Charles, perhaps you will write about SLS Man in the Lurio Report?  Charles talked about the recent successes with Orbital and Space X and the attempted return of the Falcon fist stage in the reusability test.  Charles talked about the developing nanosat business and the opening up of commercial opportunities on the ISS, all in the context of choices NASA may have to make regarding funding priorities including SLS, ISS, Commercial Crew (see  http://spaceref.com/missions-and-programs/nasa/nasa-will-face-solomons-choice-in-2014.html.

In our second segment,  Doug called in to talk about the Mars SLS option (here is the URL for the story:  www.nasaspaceflight.com/2013/10/nasa-con-ops-baseline-slsorion-mission-mars).  Doug then talked about a cislunar transportation system and how it was the key to expanding space development.  The Shackleton Energy lunar development plan came up  as did Bigelow space stations.  Charles Pooley called in from Las Vegas and guess what!!!! His Microlaunchers book is almost finished and ready for distribution!!!!  Now pick yourself off the floor so you can read the rest of the summary and listen to the show but yes, we are all in a daze, a fog and a varying degrees of shock.  I told Charles that when it is out as an ebook and a paperback, he can definitely come back on the show and talk about it.  He said it should be finished by November or so as it is out to 5 people (I am not one of them) to review and edit the manuscript.  All of here at The Space Show wish Charles Godspeed in finishing the book and we hope it meets all of his expectations.  Tim was our last caller.  He thought that if push came to shove, SLS would be shut down before the ISS.  He also suggested a Bigelow station would help enable Shackleton. I gave him and the audience a sort of business perspective on what would be needed in order for a Bigelow station to support and enhance the Shackleton plan.

Please post your comments/questions on The Space Show blog.

Comments»

1. DougSpace - October 21, 2013

OK. I see what you are saying with the equations and I believe it to be true.

However, momentum = mass x velocity (p = mv). If light has no mass then p = 0 x c. So p = 0. From this perspective, light should have no momentum and yet it does. So what’s wrong with my calculations? Does light have no rest mass yet some specific mass when traveling the speed of light?

2. John Hunt - October 17, 2013

To answer the question about how “massless photons” can have momentum as in the photon rocket, the basic equation of relativistic mechanics is E2 – p2 c2 = m02 c4, where E is energy, p is momentum, m0 is rest mass, and c is the speed of light.

For the photons the rest mass m0 = 0. So E2 – p2 c2 = 0. By transposing terms and dividing by c2 we have p2 = E2 / c2, Taking the square root of both sides we finally get p = E / c. From this we can see that it takes a lot of energy to produce significant momentum using photons as a source of thrust.

Also, if you consider a mass m0 at rest then momentum p = 0, so in that case the equation becomes E2 = m02 c4 and taking the square root of both sides we get E = m0 c2. This is Einstein’s famous mass-energy relationship.

3. DougSpace - October 9, 2013

I really hate to say it, but if push comes to shove (and I suspect it will) then I would expect NASA’s public-private (aka “commercial”) programs to get cut before SLS and the ISS. If so, this would be about the worst possible outcome because the public-private programs offer the best chance for a sustainable space program because in-space propellant can lower the costs of launches by increasing the percent of launch which is payload as opposed to propellant. As a result, more can be done with fewer launches. Also, it may not be necessary to spend the money to upgrade the SLS or develop nuclear rockets if propellant was waiting at LEO.

To be clear, beyond the current LEO programs, public-private programs could be applied to any of several objectives such as reusable launchers, fuel depots, a cis-lunar transportation infrastructure, and harvesting in-space propellant from either asteroidal or lunar sources.


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