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Mostly harmless.


Nov
8
comment Combining Gravity Turn and Orbit Models
Actually, I have yet to simulate any LDSD decelerator applications myself. I have people now who do that for me. :-)
Nov
8
comment Combining Gravity Turn and Orbit Models
I don't have a ready source for the derivation. I derived them myself (it's quite straightforward), but they are not original. I have seen equations like them many times.
Nov
8
comment Combining Gravity Turn and Orbit Models
To get the gravity turn, you will need to give it an initial kick angle at some point after launch to get it off vertical.
Nov
7
comment Combining Gravity Turn and Orbit Models
Note that your thrust to weight ratio had better be more than one.
Nov
7
comment Combining Gravity Turn and Orbit Models
The initial conditions would be $r$ at the surface and $v$ and $\phi$ at zero. Since $v$ is zero, the initial $\gamma$ doesn't matter. However if you will be applying thrust in the $\gamma$ direction, then you should set it to $\pi/2$ for straight up. Assuming you want to go straight up.
Nov
7
comment Combining Gravity Turn and Orbit Models
The initial $\phi$ doesn't matter. You should set it to zero so you can easily see how much central angle is traversed. There is no "pole" here. All points on the surface of a non-rotating sphere are equivalent.
Nov
7
revised Combining Gravity Turn and Orbit Models
added 30 characters in body
Nov
7
answered Combining Gravity Turn and Orbit Models
Nov
2
comment Bug in grouping after editing code?
Yep. Reproduced 10.0.1.0 on Mac OS X.
Oct
21
comment How to find all roots of a complex number
In this case, yes. Though Reduce promises a complete set of results equivalent to the original expression, whereas Solve has caveats, such as: "Solve uses non-equivalent transformations to find solutions of transcendental equations and hence it may not find some solutions and may not establish exact conditions on the validity of the solutions found."
Oct
21
answered How to find all roots of a complex number
Oct
20
revised How can I read compressed .Z file automatically by Mathematica?
added 7 characters in body
Oct
20
revised How can I read compressed .Z file automatically by Mathematica?
more formatting
Oct
20
revised How can I read compressed .Z file automatically by Mathematica?
reformat
Oct
20
revised How can I read compressed .Z file automatically by Mathematica?
reformat
Oct
20
comment How can I read compressed .Z file automatically by Mathematica?
Turned out that I couldn't use the register facility for this. Instead I modified the down values for Import and ImportString. See the comments in the code above.
Oct
20
revised How can I read compressed .Z file automatically by Mathematica?
update code
Oct
18
revised Plotting on the Raspberry Pi
add image of icons
Oct
18
comment Plotting on the Raspberry Pi
The Wolfie icon runs what was previously known as the Mathematica kernel.
Oct
18
revised Plotting on the Raspberry Pi
add fix for icon