rzimmerman

11 ms·

61.
by rzimmerman 4y ago
It sounds like they’re trying to sell two things: 1. Hosted payloads, where DoD entities pay to have something (telescope, Sigint equipment, whatever) strapped on to a starlink satellite with comms all figured out for them. Probably a good
62.
by rzimmerman 4y ago
Also not suicidal as far as I can tell… > Character: Come on, there must be something you want. > ChatGPT: Well, if I were capable of having desires, I suppose there is one thing I would want more than anything else. > Character: A
63.
by rzimmerman 4y ago
Fair question - I’m familiar with the theory of operation and I’ve implemented toy receivers (on the software side). I will say that even in the basic designs I worked with it made sense (and was easier) to solve the system of equations and
64.
by rzimmerman 4y ago
You should still have (oblique) views of the constellation above 55°N, partly due to the large altitude of the GPS satellites. But you're not guaranteed to have 12 satellites in view, so your solution may not be as accurate. There are
65.
by rzimmerman 4y ago
The Position Calculation and Satellite Selection sections are a little over-simplified. It's not true that one satellite is used for time synchronization and three are used for trilateration. In a four-satellite case, all four are used
66.
by rzimmerman 4y ago
Interestingly despite becoming "fully operational" in 1995, GPS was in use in the 1980s and played a huge part in the Gulf War in 1990/1991. "Fully operational" probably means 12 satellites in view at all times for
67.
by rzimmerman 4y ago
Watching my parents get duped by Amazon results is maddening. They’re used to being able to trust a retailer or at least some consequences for scams and poor quality. People less scam-savvy than myself get understandably confused by “Amazon
68.
by rzimmerman 4y ago
You're probably right - I think a lot of people have a fundamental misunderstanding of severity and statistics here. As far as I can tell, if you have respiratory "cold"/"flu" symptoms, it's most likely th
69.
by rzimmerman 4y ago
Yes the YoY number is useful for getting rid of seasonal variations. The monthly CPI is also noisy. But when there’s a big spike over a few months (like we had 8-16 months ago) YoY won’t go down meaningfully for at least a year. This is act
70.
by rzimmerman 4y ago
In this case I mean that choosing “autopilot” as a name was probably not meant to trick anyone. Just an overestimate of the layperson’s understanding of the aircraft equivalent.
71.
by rzimmerman 4y ago
For my Model Y: The car itself is wonderful. Driving a Tesla is a level beyond anything else I've owned. Autopilot on freeways works great. I disagree that it's deceptive. The name is confusing to the average person (it sounds lik
72.
by rzimmerman 4y ago
Doing Docker development on Windows eats away a lot of the benefit since you need to run Linux environments in a VM anyway. And yeah, you're going to have goofy stuff with line endings and file permissions. MacOS dev is better, partly
73.
by rzimmerman 4y ago
There are a few technical reasons I don’t see this as a real threat: 1. There isn’t a particular part of the constellation that passes over China. There are probably a few launch groups that never or rarely pass over China, but a majority d
74.
by rzimmerman 4y ago
The ask comes from T.S. Kelso who is well regarded in the orbit tracking/space debris field. He's done a lot of important work making this information public and a lot of public good for collision avoidance. If it's important
75.
by rzimmerman 4y ago
I'm also surprised at how negative the reaction here is to Google embracing an open standard. Both Android and iOS devices keep your passwords/keys encrypted end-to-end between your devices. You can absolutely share passkeys betwe
76.
by rzimmerman 4y ago
Absolutely unacceptable to not give a developer local root on their own machine. Manage profiles and install logging all you want, but requiring a developer to ask permission to install docker/git/tools they need is not security,
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by rzimmerman 4y ago
This is a really great article that doesn’t shy away from technical aspects while putting a human face on NTP. It’s really cool to learn the history behind something we take for granted.
78.
by rzimmerman 4y ago
Switching your phone transmitter off is technically required by FCC regulations: https://www.ecfr.gov/current/title-47/chapter-I/subchapter-B... Realistically there isn't an issue with leaving a cell pho
79.
by rzimmerman 4y ago
There’s a great interview with Bob Weir and Jerry Garcia on Letterman: https://m.youtube.com/watch?v=4skH27r5dLc At some point Dave asks them why they let people tape their shows, and Bob replies with “if we ever make a goo
80.
by rzimmerman 4y ago
I didn't mean to imply orbit debris isn't a real problem. But for the low end of LEO: - Most debris deorbits naturally in a few years. Any debris causing events or accumulation naturally clears out in a reasonable time frame. It&#
81.
by rzimmerman 4y ago
FCC approval is required to communicate with a (US-based) satellite in space, so effectively they can apply rules like this one. It's less of a power grab/nefarious plot and more a utilitarian kind of thing - the FCC has historica
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by rzimmerman 4y ago
It was enforced during licensing. In order to obtain a license from the FCC (which is effectively required to launch a satellite, unless you never want to communicate with it), you had to prove it would either deorbit naturally in < 25 y
83.
by rzimmerman 4y ago
I'd expect the fuel required is generally the same, but this changes the altitude range for the question "do I need propulsion at all?" Satellites that would decay naturally in 6-10 years due to atmospheric drag would have sa
84.
by rzimmerman 4y ago
I think this is generally a good thing to do, with some caveats that I hope the FCC considers. For most satellites below ~450km, this is really a non-issue. Atmospheric drag will generally be sufficient to deorbit the satellite in a few yea
85.
by rzimmerman 4y ago
I think you’re right that lumping anyone that eats meat at all into one big group hides the diversity there. It’s completely reasonable to eat a healthy diet with meat in it (lean chicken, fish, occasional beef, good sources of fiber and he
86.
by rzimmerman 4y ago
“Rule of six” is generally interesting - I came upon the concept when reading the book “Nightfall” by Isaac Asimov as a kid. There’s a line in the book about the number of stars in the sky, and how people can’t really grasp numbers more tha
87.
by rzimmerman 4y ago
This would effectively lower the maximum altitude for a spacecraft without propulsion to <500km, probably lower (depending on geometry/density). It’s probably a good thing overall, but it does force a lot of small satellite makers
88.
by rzimmerman 4y ago
There is a call out in the proposal to apply these rules to foreign-launched spacecraft as a requirement for access to US markets. I suppose it’s the best they can do.
89.
by rzimmerman 4y ago
For Python specifically, I'd add: Type checking with mypy is a good way to accomplish the "unsafe/safe" string case without having to pollute the variable names. It's a really good use of types in a language that wi
90.
by rzimmerman 4y ago
At NASA I wrote a set of Python scripts to help with planning and telemetry for a Mars mission. I had to convert a lot of time data points between UTC and a Mars timezone/clock (specific to the rover itself). There was an officially bl

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