These sources concern orbits and how software computes them. Several are project pages or short threads. This page lists thirteen sources, oldest first where dated.
Why is the crescent Moon sometimes lit on the bottom?
This is a short Q&A from NASA's StarChild site for young readers. It explains the Moon's path across the sky by season and the observer's latitude. It adds a section on folklore about the wet moon and dry moon. It gives explanation and diagrams, with no measurements.
Coding Adventure: Solar System
This page describes only the video's description text, so it is thin. The description names the topic, a public project and some learning links. The video's content was not seen.
All asteroids in Solar System, visualized
This thread discusses a demo that plots asteroid orbits from catalog data. The poster says it is a data visualization, not an exact simulation. Commenters trade explanations about gaps in the belt, detection bias and scale. The evidence is the poster's account and commenters' reasoning, with no measurements.
Post wishing for a physically accurate sublight starship simulator
This is a two-sentence post, so it is thin. It sets out a wish for a simulator and names the nearest option. Replies mention games and software. There is no data, only opinion.
Show HN: Python Simulator of David Deutsch's "Constructor Theory of Time"
The poster presents a Python library that turns a constructor theory paper into runnable code. Replies ask what it is for, request examples and question how physical the code is. One commenter doubts the theory's standing in physics. The thread has no experiments, only claims about the code and opinions.
Mother Jones post on the flaws of tech visions of the future
The post is one quoted line and a link, so it is thin. The replies are mostly short opinions about billionaires, Mars and space settlement. The linked article was not read.
The Code That Revolutionized Orbital Simulation [video]
This is a short thread under a link to a YouTube video. The video itself was not viewed. The comments are a Wikipedia link, wishes for text and graphs, and an anecdote.
Atlas of Space
This is a thin page, because the app loads by script. Only the title and a one-line description could be read. The app itself was not used.
Rocket Simulator Online - Free Rocket Launch Simulation
The page is the simulator itself, with a short description above the interface. It offers manual, guided and orbital start modes, plus a rocket builder. The text is a feature list and interface labels, with no stated author.
Lox – Oxidized Astrodynamics
This is the project README for Lox, a Rust astrodynamics library with Python bindings. It gives quick-start code, install commands and a feature list. It says the project is pre-1.0 and its API may change. The README offers no benchmarks or validation results.
Evolutionary Mission Trajectory Generator (EMTG) Open Source Release
This is the README for the open-source release of EMTG, a NASA Goddard trajectory tool. It covers dependencies, installation, a question-and-answer section and legal notices. It says the release is infrequent and support is limited. It describes the software only briefly and shows no results.
Welcome to REBOUND
This is the front page of a software manual. It lists features, integrators, contributors, related projects and papers. It also states a policy against AI-generated contributions. It describes the project and does not test it.
If the Moon Were Only 1 Pixel - A tediously accurate map of the solar system
This is a personal web project. The reader scrolls past empty space between planets. Captions give travel times and size comparisons. Later captions turn to reflections on emptiness. It cites no sources for its figures.
Glossary
- Apoapsis
- The highest point of an orbit.
- Asteroid
- A small rocky body that orbits the Sun.
- Astrodynamics
- The study of how spacecraft and other bodies move under gravity and thrust.
- AU
- Astronomical unit, the average distance from Earth to the Sun.
- Biosphere 2
- A sealed Arizona experiment in a self-contained living environment.
- Constructor
- Something that can carry out a task repeatedly and keep its ability.
- Constructor theory
- A proposed framework that states physics in terms of which tasks are possible or impossible.
- CSPICE
- A NASA toolkit for computing positions of planets and spacecraft.
- Ellipse
- The oval shape that most orbits follow.
- Ephemeris
- A table giving the position of an object in the sky over time.
- Floating point precision
- The limited accuracy with which computers store decimal numbers.
- Integrator
- A method that steps a simulation forward in time.
- J2 perturbation
- A small change in an orbit caused by Earth's bulge at the equator.
- Kerbal Space Program
- A spaceflight game that uses simplified orbital physics.
- Kirkwood gap
- A dip in the number of main-belt asteroids at certain orbital periods linked to Jupiter.
- Latitude
- How far north or south of the equator a place is.
- Link budget
- A tally of signal gains and losses between a transmitter and a receiver.
- Longtermism
- A view that stresses the welfare of people far in the future.
- Max Q
- The point in a flight where air pressure on the rocket is greatest.
- Morphism
- In category theory, an arrow that maps one object to another.
- N-body
- A simulation of many bodies pulling on each other by gravity.
- N-body physics
- A way to simulate many objects pulling on each other with gravity.
- New Horizons
- A NASA spacecraft launched in 2006 that flew past Jupiter and Pluto.
- Orbiter
- A free, realistic spaceflight simulator for computers.
- Pull request
- A proposed code change submitted to a project for review.
- SGP4
- A standard model for predicting satellite positions from published orbit data.
- SNOPT
- A commercial optimization program that EMTG can use to solve for trajectories.
- Solar System
- The Sun and the objects that orbit it.
- Specific impulse
- A measure of how efficiently an engine uses propellant.
- Sublight
- Slower than the speed of light.
- Sun-synchronous orbit
- An orbit that passes over a place at the same local solar time each day.
- Symplectic
- A kind of integrator that keeps long-run energy errors small.
- Symplectic integrator
- A numerical method for stepping a physical simulation forward that keeps energy errors from growing.
- Task
- In constructor theory, a change to a physical system that may be possible or not.
- Terraforming
- Changing another planet so people could live on it.
- Three-body problem
- The problem of predicting how three bodies move under mutual gravity.
- Trajectory
- The path a spacecraft follows through space over time.
- Tsiolkovsky rocket equation
- The formula linking a rocket's speed change to its exhaust speed and mass.
- Unity
- A game engine used to build games and simulations.
- Waxing crescent
- A thin lit sliver of the Moon that grows larger each night.