Orbital Mechanics Guides

Introduction

Here are some links to orbital mechanics stuff and dynamics in general.

Links

Three Degree of Freedom (Orbital)

https://orbital-mechanics.space/the-n-body-problem/circular-restricted-three-body-problem.html

Six Degree of Freedom (Attitude)

https://en.wikipedia.org/wiki/Tennis_racket_theorem

Lunar Informational Resources

Introduction

Here are some lunar informational tools and resources.

Lunar Season Calculator

https://www.lpi.usra.edu/lunar/tools/lunarseasoncalc/

As lunar seasons do not correspond to consistent calendar dates, this Excel workbook tool was developed to allow users to efficiently explore expected future seasonal cycles using one of two methods. The first is a direct lookup of subsolar latitude and hemispheric seasonal state for a user-defined date. The second allows the user to specify a subsolar latitude range and temporal search window and will return all date ranges for which the subsolar latitude criterion is met. Both options provide plots that place the results in context.

Subsolar latitude values were calculated for 00:00:00 UTC on each day between 1 Jan 2020 and 31 Dec 2029 using the SpiceyPy subslr module and the following kernels: naif0012.tls (LSK), de438.bsp (SPK), moon_080317.tf (FK), pck00010.tpc (PCK), and moon_pa_de421_1900-2050.bpc (PCK) [3, 4]. Reported values have about ±0.04° uncertainty due to the maximum progression of the true value over the course of 24 hours; this is assumed to be higher than the degree of precision achieved with SPICE kernels over the decade the calculations cover.

The Lunar Season Calculator was developed by Sam Cartwright and Jordan Bretzfelder. We thank Dr. David Kring and LPI for their interest in hosting the tool. We are also greatly indebted to Andrew Annex and the other contributors to the SpiceyPy project. For questions or comments, please contact scartwright@nevada.unr.edu.

Lunar Surface Innovation Consortium

The purpose of the Lunar Surface Innovation Consortium (LSIC) is to harness the creativity, energy, and resources of the nation to help NASA keep the United States at the forefront of lunar exploration.

LSIC operates in collaboration with the NASA Space Technology Mission Directorate under the Lunar Surface Innovation Initiative (LSII). LSIC fosters communications and collaborations among academia, industry, and Government. Members have expertise in LSII key capability areas.

Space: Beautiful Sites

Space: Beautiful Sites

A possible future city on another world?

Not all need to be rocket scientists to appreciate the great beauty of the beyond. Take a look at some of these wondrous sites:

Stuff in Space
http://stuffin.space/
See everything that's around the Earth man-made and what-not.

Asterank
http://www.asterank.com/3d/
Truly beautiful asteroid visualizer.

Deep Space Network
https://eyes.nasa.gov/dsn/dsn.html
NASA's Deep Space Network (DSN) updated every 5 seconds. DSN is used by all NASA interplanetary spacecrafts.
 
ISS Interactive 3D Visualization
https://heavens-above.com/ISS_3D.aspx
See the International Space Station at any time and fully zoomable & rotatable.

Ofrohn's Celestial Map Github Project
https://ofrohn.github.io/
Adapatable celestial map done with the D3.js visualization library. Check it out! For instance, the celestial sky viewer: https://ofrohn.github.io/celestial-demo/viewer.html

Milky Way Halo
https://armchairastronautics.blogspot.com/p/milky-way-halo.html
With this site, you can see the whole universe in terms of galaxies, clusters, halos, etc.

[Space] Interview with Adriano Autino (Space Renaissance International)

Research: Proposed Aerospace Papers

Predicting the Fate of Humanity for the Next Century
Much has been said about the Fermi paradox, the paradox on why if there’s supposed to be intelligent civilizations out there, we humans have not observed any sign of life. One depressing but possibly true answer to this paradox is that almost all intelligent civilizations eventually discover weapons of mass destruction and end up destroying themselves before expanding via spaceflight. In Michio Kaku’s book Hyperspace a while ago, the physicist made the statement that the next 150 years will be a pivotal stage of whether humanity will expand into the stars or revert itself to the stone age or become extinct. In this paper, a prediction following the spirit of Drake equation is proposed. This equation is called the Shen equation, i.e. Global Calamity Equation, and it predicts the probability that human civilization will terminate within a given amount of time:

P(civilization termination) = P(Nuclear War)*P(Global Epidemic)*P(Asteroid Impact)*P(Ecological Collapse)

The probability for each calamity is based on best estimates from literary reviews in their respective fields.

Modeling Galactic Civilization Expansion and Encounters
Though alien life has not yet been confirmed, it is interesting to speculate on the state of galactic affairs in the universe. How has galactic civilization evolved over the eons? Does contact between different civilizations necessitate growth or decay? If human civilization provides any indication, contact between human civilizations has seen the imminent collapse of less technologically advanced civilizations when confronting more advanced civilizations. However, this has not always been the case and sometimes both civilizations benefit.

In this model, the galaxy is modeled as a distribution of possibly habitable systems on a three-dimensional grid following the best estimates of recent exo-solar planet discoveries. With the passage of the first time step, i.e. a millennium, each galactic civilization expands by ten light years from its home star system. With the passage of the second time step, i.e. a millennium again, each galactic civilization expands by one hundred light years (to take into account technology advancement). This exponential rise continues indefinitely. Each star system encountered is settled thus unless already settled by another galactic civilization. Upon civilization encounter, a random number is generated which decides whether the star system changes hands between civilizations, remains the same, or is annihilated. The entire simulation is run for 1000 time steps or until the galaxy is thoroughly colonized.

On Piezoelectric Power Generation from Space Debris
With the inevitable rise of space debris in the near future, protection from hypervelocity impacts has become an important issue for any spacecraft launched. Given the high kinetic energy yield of such impacts, an idea is proposed to capture such kinetic energy through piezoelectric materials incorporated into current Whipple Shield designs. Capturing such energy can be used to power components such as onboard batteries. A model and design of such a space power shield is proposed here based on experimental and theoretical models from NASA’s ORDEM2K.

[AERO] How to Not Travel (Interplanetarily)

Re-reading Robert Zubrin's books are fun since this guy has a definite cheeky sense of humor. Over spring break a few months back, I went to New York City and checked out the American Museum of Natural History while I was there. Surprisingly, there was a section in the museum for space. That was unexpected in a natural history museum but I suppose they just have to have everything. [Image Credit: Buzz Aldrin Mars Cycler - painting by Don Dixon for Scientific American]

Anyways, while I was at the Rose Center for Earth and Space, I happened across the book How to Live on Mars by Robert Zubrin and acquired it there. This book is a hilarious practical guide for anyone seeking to leave Earth and live in life in the late 21st century. Each chapter focuses on a specific aspect of Martian survival which includes how to get there, what to wear (outside of course), what rovers to get, what homes to acquire, how to choose what to have in the habitat, how to not get fried by radiation, etc.

The book is for a non-technical audience but occasionally there's some interesting science thrown in with a huge warning note that says High Science Content. One thing that I found quite amusing was his rant on cyclers. I had a friend who worked on cyclers for his Master's thesis back at Georgia Tech and I wonder what he'll say about this. Let me go on with Zubrin's points on disadvantages of cyclers.

Cyclers, short for cycling space stations, are huge space stations built to last a long time for the role of allowing permanent transfer orbits between Earth and another planet like Mars. Once setup, such large structures do not have to be relaunched and people can just catch the trip by catching the cyclers in small, fast "taxi" capsules fired from each planet. Yet, there's definite issues which I have ascertained from reading and reflecting on Zubrin's intelligent rants:

1. Since it's built to last a long time, the one you're using is likely mold infested and breaking down. Unsanitary ancient bilge cans do not sound very appealing though it may be cheap.
2. The taxi may miss the cycler and if so, you just paid a trip for nothing.
3. [High Science Warning] The trip takes longer than a typical Hohmann transfer (HT) since a Hohomann transfer to Mars requires 8.5 months--round trip time will be 17 months. This doesn't synchronize with 12-month orbital period of Earth. If a spacecraft leaves Earth on a HT, it will not rendezvous with Earth when it comes back. The trip must have a Type 1 leg as well as a Type 2 leg either on outbound or inbound. Either way, passengers will be stuck with the slow boat on one way.
4. [High Science Warning] Cyclers are inefficient in its usage--not a problem for you maybe but certainly for the government paying to keep it afloat which you are paying taxes for. The minimum orbit time for cyclers designable to rendezvous with Earth is two years. However, that's not synchronous with Mars, whose orbital period is 23 months. The only solution is to have multiple cyclers with each one used for Earth-Mars transport once every six or seven years. 

Some interesting issues right? We'll see how it pans out in the future but I think Zubrin has convinced me not to support cyclers if they ever do gain a broad interest.

[Image credit: http://buzzaldrin.com/]