Mission to the Gravitational Focus of the Sun: A Critical Analysis

For a more critical look at this concept, I recommend "Mission to the Gravitational Focus of the Sun: A Critical Analysis". https://arxiv.org/abs/1604.06351

https://www.centauri-dreams.org/2020/12/10/developing-focal-... (and its critical analysis) https://arxiv.org/pdf/1604.06351 I believe that work on such a project would be interesting, even if it isn't ever done. It is something that if you worked on it as a grad student, and then became a professor and your grad students worked on it ... and they became professors and their grad students worked on it - they'd be the ones seeing the results. Not so much a "this is a way to do things..." but rather a "thinking about research that spans generations and the problems that they solve in the process of doing that great project has useful spinoffs." A mission out to 550 AU at New Horizons speed of 2.9 AU / year (it still boggles the mind of talking about those speeds and distances) is nearly 200 years from launch to primary science objective. It's "only" been 45 years since Mariner 2 to New Horizons.

So if this probe is bound to venture into the distance range useful for a solar gravitational lensing telescope, why not use it to deploy one? That would really be a major breakthrough IMHO. https://arxiv.org/abs/1604.06351 "The minimum distance for a solar lensing telescope is 547 astronomical units (AU). And in reality, proper positioning would likely require the telescope to be placed even farther out — perhaps as far as 2,000 AU or more."

In principle, I am right with ya. We need ways of beating (or at least coping with), the diffraction limit. It's fun to think of, say, stuff like this: https://arxiv.org/abs/1604.06351 (as far as big lenses go) Using the sun as a gravitational lens would be pretty sweet. I have a feeling we will have some more tricks to play with E&M locally before we can go to space on that scale though. edit: My own semi-blind musing has made me curious: metamaterials for super-lensing: https://arxiv.org/pdf/0905.0263.pdf entanglment enhanced microscopes?!: https://arxiv.org/abs/1401.8075 (@shpx linked to this quantum stuff before me, by the way)

Actually the proposal is a bit more complicated than using a 12 meter large antenna, it is sending this antenna at 550 AU (the FOCAL in "FOCAL antenna"). Geoffrey A. Landis wrote: "The gravitational field of the sun will focus light from a distant source to a focal point at a minimal distance of 550 Astronomical Units from the sun. A proposed mission to this gravitational focus could use the sun as a very large lens, allowing (in principle) a large amplification of signal from the target, and a very high magnification." https://arxiv.org/abs/1604.06351

If you're interested in a critical review of FOCAL (which is also rather interesting) - https://arxiv.org/pdf/1604.06351.pdf I am on the "this is a really hard problem - but an interesting one" category. It seems like it will take a number of significant improvements on top of current technology - but it seems like it would be doable in another few decades if we continue to improve (the difference between Pioneer and New Horizons is 35 years... if we can do that much improvement again we might have something). It is still something that if you are a grad student working on it now, it would launch when you retire, and your grad students when you retire - when they retire, it is their grad students who would be doing analysis of the data. I tend to believe this would be a good thing to do because it would be working on that time frame and getting us to think about projects that will run for a century rather than a budget cycle.