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Very Long Baseline Interferometry

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6:29 am
May 12, 2010


Luke Maurits

Adelaide, Australia

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VLBI is a technique used in radio astronomy which involves positioning several small (relatively speaking) radio telescopes over a wide area – spanning a continent or even several – and combining received signals from all of them, using clever algorithms, and emulating a single extremely large telescope (larger than could be physically built).

Techniques which replace one extremely large and expensive piece of equipment with a large number of relatively small and cheap ones are fantastic candidates for internet-based open source projects like CSTART.  Maybe we could set up a VLBI project?  This would be entirely Earth based and presumably ITAR free, or at least "ITAR reduced".  It's also very "sane" looking and could look extremely attractive to radio hams and/or amateur astronomers.

I don't know an awful lot about the technique, so I don't know how small the individual antennae can be while keeping the entire array worthwhile, but it is worth looking into.

Amateur VLBI projects are not unheard of – see, e.g., this site.  It's possible we could adopt an extra project, say by offering to help fund it.

Something to think about, anyway.  Obviously somewhat of a moot point until / unless CSTART manages to pull itself out of its current coma.

Main CLLARE workgroups: Mission Planning, Navigation and Guidance. I do maths, physics, C, Python and Java.

3:40 pm
May 12, 2010


Rocket-To-The-Moon

Altus, Oklahoma, USA

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The idea has crossed my mind in the past of sending two probes in opposite directions so that they form a multi-billion mile baseline. I believe the problem with this is that, while the baseline is very large, the actual antenna size is small so the sensitivity cannot be realized.

 

This would be something that could be possible to accomplish. To me it seems like the engineering required would be a standardized motorized mount, and control software. Individual dishes could essentially be autonomous once they are set up.

Main Workgroups: Propulsion & Spacecraft Engineering

3:30 pm
May 13, 2010


antinode

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Could this work in a vein similar to that of distributed computing in that anyone could contribute their own dish node that would add resolution to the overall dish array?

6:30 pm
May 13, 2010


Luke Maurits

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This is certainly how I envisaged it working.  I would need to do more working on how VLBI actually works to get a clearer picture of how we could go about it, though (and I won't be able to do that for a while  – I'm extremely busy at the moment and any spare time for CSTART I am spending on my propellant mass analysis report).

It's possible we could also have a purely distributed computing project for those who can't afford dishes, which would do the work of combining all the separate signals.  I don't know how intense the algorithms for doing that are, it might be that we don't really need to distribute it, but the distributed option is always there if we do.

Main CLLARE workgroups: Mission Planning, Navigation and Guidance. I do maths, physics, C, Python and Java.

9:37 am
May 15, 2010


Rizwan

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Any idea on what would the cost of setting up such a thing be?

10:04 am
August 31, 2010


Sci

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If memory serves, the key getting VLBL working is a very accurate time-base.

I found and contributed to a thread at stargazerslounge.com discussing optical arrays. The impression is that it's currently beyond amateur capacity to do so. However radio arrays may well be possible.

http://stargazerslounge.com/eq…..ost1368331

My primary point was that the recent developments in chip-scale atomic clocks could provide a readily accessible and accurate time-base. Would the next generation of GPS satelites be able to provide the nessesary relative positioning information?

Provider of practical solutions.

Sometimes stellifying Jupiter IS the practical solution.

2:44 am
September 1, 2010


Luke Maurits

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Thanks for posting that link, Sci!  Very intersting and encouraging to see other communities considering roughly similar ideas to ours.  I don't really at the moment know enough about VLBI to say much more about how feasible this is, but if anybody with more knowledge wants to do the research and/or flesh out the details, they should feel absolutely welcome and encouraged.  It would be great to see a project like this take off.

Main CLLARE workgroups: Mission Planning, Navigation and Guidance. I do maths, physics, C, Python and Java.

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