Guest:  Joe Carroll;  Topics: Mitigating the orbital debris problem, Joe's analysis via his PPT presentation, "New Options for Orbital Debris" which has been uploaded to The Space Show program for Feb. 26: www.thespaceshow.com/show/26-feb-2023/broadcast-3990-joe-carroll.

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We welcomed Joe Carroll back to the show, this time to address orbital debris problems.  In fact at one point later in the show, he said we needed to get serious about the orbital debris problem so this program was a call to action by Joe.  Note that Joe prepared a PPT presentation for the program, "New Options for Orbital Debris" which you can find on our blog for his Sunday program.  Joe referred to the presentation multiple times during the interview but if interest, I suggest you go through the presentation page by page.

Joe started the discussing by responding to my question about how and why he got interested in orbital debris.  Joe's interest in the subject dated back decades so do listen to his involvement in the field back when the problem was not always recognized as a problem.  Joe's brief history and look back was about a third of our program.  When I did move forward from his background, it was when I asked him for his assessment of our TRL today to mitigate debris, mostly in LEO. Joe responded by sharing some important stats with us as to who was and is (under current law) responsible for most of the LEO debris. The answer was Russia (the former Soviet Union) with about 2/3 of the orbital LEO debris own by Russia.  Joe move on saying that debris needs regulations and said right now we "can't touch other people's stuff."  Joe continued with his statistical analysis, mostly for LEO debris, then moved on to talking about cubesat and constellation concerns.  Don't miss this important part of the discussion as you likely will not have heard the information Joe shared with us elsewhere. 

One important part of this discussion was the altitude being used by various constellations from Starlink to One Webb and a few we might not be that familiar with -so far.  Joe said the constellations and altitudes were wake up calls.  His rule was that lower altitudes were better.  Listen to his explanation for that conclusion.  In talking about the need for lower altitudes, Joe commented on the FCC rule to deorbit a bird after 25 years of useful life.  Joe thought this was too long so listen for his preferred way of dealing with no longer functioning satellites and hardware in orbit. 

Following this discussion, we started talking about the old Space Shuttle external tanks.  Joe mentioned his background on trying to use the tanks in space for various purposes, the people he met with and the actions taken.  Marshall called to tell us about an old President Regan appeal to send in ideas for how to use the tanks in orbit.  I even talked about the effort to use them for space tourism orbital hotels.  Our discussion included talking about their size and vulnerability to extreme temperature changes in space from one end to another.  We talked debris and external tanks for a good ten plus minutes so pay attention to this subject. It was a new one for me in the orbital debris conversation.  Maybe new for you too.  We did get an email from a listener asking where the tanks were today and if any survived and were usable.  Joe did not know the answer to that one.

Next, Joe talked about the added responsibilities given to the Dept. of Commerce re debris issues but seemed to indicate the outcome of having done this was still unknown.  Joe had much to say about the responsibilities and concerns with the DoC.  Joe also said that we could see the tracking information at the Space-Track.org website.  In talking about the DoC, more was said about the FCC 25 year rule and the need for regulating constellation altitudes.

Joe pointed us to his Slide 14 for the purpose of explaining why we need to do a better job of estimating the real cost of orbital debris. He took us through a short form analysis of the problem show why it was important to improve upon.  As we were now closing in on the end of the program, Joe commented that the orbital debris company Astroscale might actually shift to making the bulk of its money from the development of their new on orbit servicing business rather than from debris removal.  Once again Joe made a serious call to action that this issue needed to be addressed, he briefly went over the reasoning which was explained more fulling in this discussion and then he talked about clustering the likely use of smart barnacles and tools for mitigation.  Before leaving, he suggested several books for us to read including a few that focused in on managing the commons. 

Please post your comments/questions for Joe on our blog.  You can reach Joe through me or his information on the title page of his PPT presentation uploaded to our blog page for this program.