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### Flying fuel tanks! Which deep-space spacecraft had the largest fuel mass fraction?

The Los Angeles Times' Deborah Netburn just wrote a really nice retrospective; ‘OK. Let’s do it!’ An oral history of how NASA’s Cassini mission to Saturn came to be with plenty of photos and quotes ...
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### How does the pattern on the MarCo cubesat's antenna boost data-transmission?

I was looking at a few posts that uhoh had made about the MarCo cubesat. One of the pictures was the one that I've posted below: Source The most I can gather from casual NASA articles is along the ...
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### How is long-distance optical communications coming along in space?

I remember there was a test of optical communication and some data transfer from lunar orbit to earth, and I think the ISS uploaded (or downloaded-up? which is correct here?) a movie from earth. In ...
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### What is the largest proper cubesat?

The sizes of Cubesats are measured in "U" units of volume. Each U is nominally a cube of something like 10 to 12 cm on a side, depending on the specific deploying mechanism it's approved for....
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### What is the highest non-optical frequency used or tested for use in deep space communication?

For dish antennas used to transmit a signal over large distances, the on-axis gain scales as $D^2/ \lambda^2$ or $D^2 f^2 / c^2$ where $\lambda$ and $f$ are the wavelength or frequency and $c$ is the ...
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### Quantitatively, why will optical communication be better than X-band for deep-space communications?

In a question about communicating with Voyager, an answer asserts: [70 meter dish antennas deployed in space] just isn't done, and it probably won't be, since optical communication is definitely ...
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### Are there plans or a program for an optical relay pathfinder for deep space?

In Glenn Research Center's Richard Reinhart's slides Space Communication and Navigation TestbedCommunications Technology for Exploration for the 2013 ISS Research and Development Conference I saw an ...
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### What is the current status of Stirling engine-based radioisotope generator technology?

@Heopps' cool answer to the question Any proposed missions to explore the black liquid on Titan? Technical challenges? has an interesting line: ASRG generator was planned as compact energy source ...
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### Mass ratio of solar-electric versus radioisotope thermo-electric power for propulsion; beyond how many AU do RTGs win?

Solar-electric propulsion has been used several times now in deep space missions. This question explores the scalability in comparison to Radioisotope thermoelectric generation or other nuclear-based ...