Building bridges Falcon 9 sucessfully lands on sea drone

Dragon successfully splashed down at 11:51 am PT in the Pacific Ocean, completing the Commercial Resupply Services 8 (CRS 8) mission which began with the liftoff of Falcon 9 and Dragon back on April 8th.

Here we have only two switched reference voltages: 0 and 1.0000. (As we shall show later, we can tweak the high end even if this voltage is not precise.) Here we have added a number of flip-flops such as CMOS types 4013 (which come two to a chip).
The high end tweak on the other hand, may use any of a number of techniques. But this involves smaller adjustments, such as small resistors or small capacitors. These may well not be actual trim-pots, but slightly different fixed components.

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Now, moving on to the high-end tweak. Assuming we have the lower ranges optimally adjusted, we have only to turn up Vo until we are in a higher range (changing the number of flip-flops in the upper chain if desired) and we repeat the procedure with the tweaking mechanism. Perhaps the upper octave is just a bit flat. We might simply add a few hundred ohms to tweaking series resistor. Note that nothing involved on the high end depended on your having the lower octaves at exactly 1 volt/octave.

The longest continuous EVAs of all time

For example, what if your supposed 1 volt source were actually 0.98 volts. It may be that you will need to readjust the volts/octave not just because your reference voltage was inexact, but ultimately to match to your keyboard which is likely also inexact. But this you would have had to do eventually anyway. The point is that the high end compensation is almost certainly still near perfect. [If it helps, consider that you have “souped up” the high-end switching, just as though you used a faster component, and it now works in that upper range.

Photo by:  Erez Attias

Astronaut Continuous EVA
Anatoliy Solovyov 78.79
Michael Lopez-Alegria 67.67
Jerry Ross 58.63
John Grunsfeld 58.50

It was our practice to (simply) show the control inputs for all our VCOs as three parallel 100k resistors, while the accompanying text indicated that (the input stage being a summer) we could have additional inputs, variable inputs, coarse and fine manual tuning, etc. You would however almost certainly have one input dedicated to the keyboard.

Dragon delivered nearly 7,000 lbs of cargo and returned more than 3,700 lbs of cargo, including 1,300 lbs of science.  Dragon is the only operational spacecraft capable of both delivering and returning significant amounts of cargo to and from the International Space Station.

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  1. It is straightforward to envision the tune-up procedure. If we had a good ear, we might just set an initial frequency with Vo, and then rotate the Vc switch and listen to hear if the lower octaves are sharp or flat.

    1. Great article, I am looking forward to apply this in real life. Thanks for taking the time to write.

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