# Tag Info

### Do the dimensions match in Kepler's equation?

$$\newcommand{\sin}{\mathop{\rm sin}\nolimits} M = E - e \sin E$$ Note that this expression only works when $M$ and $E$ are expressed in radians. Radians are a measure of arc length divided by radius,...
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### Why will Starlink Gen2 be so big and heavy?

"Just a Flying Router" This is... not the half pound plastic wifi router in your house. I don't think there are firm numbers out yet, but the speculation I've seen is that bandwidth on a ...
• 1,693
Accepted

### What is the Falcon 9 interstage used for?

On the Falcon 9, the interstage is attached to the top of the first stage and remains attached to the first stage. It also contains the mechanisms for the grid fins, and the grid fins themselves. The ...
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### What are the rough dimensions of the ISS?

Dimensions of the ISS (in real units) at each step of its construction can be found in these documents: On-Orbit Assembly, Modeling, and Mass Properties Data Book volume 1, 2002 On-Orbit Assembly,...
• 128k

### What determines rocket height/width?

What determines rocket height/width? If there had to be a concise answer, it would definitely be @JCRM's answer that it's an optimization of a series of compromises. But there'd have to be a caveat ...
• 149k

### What is the geometric dimensions of turbo pumps present in SSME?

From: https://gandalf.azureedge.net/shuttle.html Specifically page 4-19: https://gandalfddi.z19.web.core.windows.net/Shuttle/SSME_MPS_Info/RSS-8559-1-1-7%20-%20Inspection%20Criteria%20for%20Space%...
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### J-2 rocket nozzle length

FWIW, here are J2-S numbers. The paper "Altitude Developmental Testing of the J2-S" gives the throat diameter as 12.192 inches and the expansion ratio as 39.62. Paragraph 2.1.1 Thrust Chamber — ...
• 183k