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KerbalEDU Exploration of TRAPPIST-1 ( Principia variation of SLIPPIST-1 )


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Conceptual photosynthesis with M, K, G, F type stars.  Source: "The Color of Plants on Other Worlds"


Where Planet Years are only a few Earth Days...more like Jupiter & its large moons.

1.5 b,  2.4 c,  4.1 d,  6.1 e,  9.2 f,  12.4 g,  18.8 h 

Earth days per "year"




       This "Topic" is an invitation to join an exploration of the TRAPPIST-1 system ...students, teachers, KSP players all welcome to share fun & significant TRAPPIST-1 related insights...

  • missions you build either for SLIPPIST-1 or TRAPPIST-1,
  • a place to share your explorations of this exoplanet  system,
  • contrasts with Jupiter or Pluto moon systems in KSP RSS Principia, e.g. orbit transfers, etc.,
  • cool research you discover about this system,
  • remarkable moments encountered while exploring this model system in Kerbal,
  • etc, focus on creating together a fun & educational concentration of information about TRAPPIST-1 & our exploration of it.

NASA JPL: TRAPPIST-1 Compared to Jovian Moons and Inner Solar System - Updated Feb. 2018


"All seven planets discovered in orbit around the red dwarf star TRAPPIST-1 could easily fit inside the orbit of Mercury, the innermost planet of our solar system. In fact, they would have room to spare. TRAPPIST-1 also is only a fraction of the size of our Sun; it isn't much larger than Jupiter. So, the TRAPPIST-1 system's proportions look more like Jupiter and its moons than those of our solar system."


Observe 'actual' planet transits in Kerbal!

       For the Principia adjusted version, the epoch start date is  "JD2457000.000000000" =  UTC Noon  Monday 2014 December 08.  Here is an excerpt from the Principia GitHub FAQ:


"The simulation uses the most recently published observational data (from K2 and Spitzer) and is based on a transit-timing variation optimization. It accurately models the real-life behavior of the planetary system: the transits are accurate to within a minute."



a remarkable model of the TRAPPIST-1 system 

requires x64 KerbalEDU or x64 KSP

Created By:

@GregroxMun ( SLIPPIST-1 ) & the Principia team @eggrobin & @pleroy

( TRAPPIST-1 for Principia )


source: https://www.eso.org/public/unitedkingdom/images/eso1615e/


source: https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA22096


Save files & Mission links (To_Be_Added):

  • TRAPPIST1_system
  1. stationary 1d orbit
  • Jovian system 
  1. stationary Europa orbit

"This chart shows, on the top row, artist concepts of the seven planets of TRAPPIST-1 with their orbital periods, distances from their star, radii, masses, densities and surface gravity as compared to those of Earth. These numbers are current as of February 2018."  source link


Seven Worlds of SLIPPIST-1, and an Astronomy Lesson on Stars and the Exoplanets around TraPPiST-1


At the above link, Gregrox has written a fun & insightful astronomy lesson with some cool details about the beautiful model images of this system...'almost eyeball' planets & all!...a few excerpts:

  • "You get a hot zone, and then progressively cooler zones down to the night side of frigid temperatures and nothing but ice! You'd have a band of scorching desert, a band of rainforests, a band of tundra, and a massive cap of ice. Or if it's colder and wetter, it can look even more eyeball-like, maybe a cracked frozen ice ball like a huge Europa with a circular sea of melted ice. But these don't account for the fact that real tidally locked exoplanets spin. The Coriolis force drives winds that completely change the climate."
  • "Try to figure out the resonant chain in TRAPPIST-1! Just kidding, I'll tell you. It's in a 24:15:9:6:4:3:2 resonance. Neighboring planets are in 8:5, 5:3, 3:2, 3:2, 4:3, and 3:2 resonances"
sGnb2Zc.png  Gregrox SLIPPIST-1
Note 2022 January:
KerbalEDU has been reverted to the installer based version 1.2.2. 
SLIPPIST-1 v0.4 may need to be used with the 1.2.2 version as well as 1.2.2 compatible versions of its dependencies Kopernicus, Kopernicus Expansion, ModuleFlightIntegrator.  Use CKAN to help locate the version for the old KSP 1.2.2. 
Also, such old versions of Principia are not supported by its developers, using Principia without support in KerbalEDU 1.2.2 requires  Principia Cramer and its specific install dependencies (also study the Principia install instructions) as that was the last version to support KSP 1.2.2. 
Configure in KerbalEDU x64 1.4.5
Extract the correct subfolder for each of the following mods to the KerbalEDU GameData folder:
KerbalEDU x64 1.3.1 Install Instructions, SLIPPIST-1 & Principia mod page links, & additional useful Mod lists (see hidden contents):

Essential MODs:

  • PRINCIPIA REQUIRES x64 version of KerbalEDU or KSP
  • KSP page for SLIPPIST-1
  1. Kopernicus
  2. Kopernicus Expansion Continued

Many Useful Optional MODs see CKAN file or the list at the google doc links below:


For KerbalEDU 1.3.1 You must use Principia release (Fatou):  This is the last version to support KSP 1.3.1 and 1.4.5

Download the binary (Macintosh, Ubuntu, and Windows) here for 1.3.1


KerbalEDU 1.3.1 Install Instructions for SLIPPIST-1 & conversion to TRAPPIST-1:

Install Instructions for SLIPPIST-1 & conversion to TRAPPIST-1

Link to the original instruction post: 




You'll want to use version 0.6.0 with KSP 1.3.1. All you need to do to make sure the game is installed correctly is the following:

  • Install Kopernicus from THIS direct download link.
  • Install Kopernicus Expansion Continued--Regional PQSMods from THIS direct download link.
  • (OPTIONAL) Install E.V.E. version for 1.3.1, only the plugin. Do NOT download the configs, SLIPPIST-1 has its own.
  • (OPTIONAL) Install Scatterer version for 1.3.1.
  • Download the KSP 1.4.x version of SLIPPIST-1 (v0.6.0)
  • Unzip the folder and install only SLIPPIST-1 into gamedata, do not install the newer version of Kopernicus Expansion.

(In short, install Kopernicus and Kopernicus Expansions Regional PQSMods for 1.3.1, making sure not to overwrite Kopernicus Expansions when you install SLIPPIST-1.

ADDITIONAL Principia Install instructions To  ADD  Principia to make the SLIPPIST-1 model quite accurately reflect the observed transit timings with the epoch start date "JD2457000.000000000" =  UTC Noon  Monday 2014 December 8 
Install the most current release of Principia from the link to the right
ADD to your GameData  folder the "Trappist-1 for Principia" folder download available from the  link to the right





Edited by AloE
WIP updates
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StarryNight7 suggests that the plane of the planet orbits in the TRAPPIST-1 system appears to be about perpendicular to the plane of the Earth traveling around the Sun. 

The Sun is ~40ly in the distance slightly left above image center & the pink ~horizontal  line approximates the orientation of Earth's orbit around the sun:


TRAPPIST-1 'near' the Moon in the sky

Some times, like on 2018 September 23, 

the Moon passes near line of sight for an observer on Earth towards the Trappist-1 system: 

(click image to see detail)OhEJFg2.png

Graphics courtesy of Starry Night® 7 Pro Plus  / Simulation Curriculum Corp.

Edited by AloE
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NASA artists suggest planets as Earth like 'apparent view' sized moons in the sky viewed from some planets in the TRAPPIST-1 system...but the NASA painting is a bit exaggerated ;-)

Indeed at some points in the orbits especially for planets 1c & 1d, planet 1b is over 2x the apparent size of our moon & the sun TRAPPIST-1 nearly 10x the apparent diameter of Earth's Moon & Sun...the views of TRAPPIST-1 solar transits, of large crescent 'planet' phases near greatest elongation, & of some of the planets going from brilliant 'dot sized' to as large in the sky as we see our Moon from Earth in just a day or so are highlights for tourists in orbit of 1c :-) 

However, closer to home, the view of Jupiter from Io as well as Io & Jupiter from Europa would be stunning...especially for the 2032 March 20 Jupiter tipple shadow transit!  Even just the 3 shadows would barely fit into the field of view of 7x50 binoculars!  The apparent diameter of Jupiter being a gorgeous equivalent to ~30 Earth's sky apparent Moon diameters.

Animated gif below alternates views from TRAPPIST 1c & view from Io...many more detailed StarryNight7 & Kerbal images in the album at: https://photos.app.goo.gl/vTwF5QSW795yoNeg6




Graphics courtesy of Starry Night® 7 Pro Plus  / Simulation Curriculum Corp.


Edited by AloE
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  • 2 months later...

KSP TRAPPIST1 for Principia video comparison with published planet transit data.  Considering the opportunity to create KSP 'observatories' as well as 'tourist' colonies to explore 'real' events in KerbalEDU...

and experience the differences between the Jovian & TRAPPIST1 systems.

TRAPPIST1 planet 1b is about 45 minutes early compared to published data...whereas planets 1c,1d,1e,1f,1g,1h transit within a few minutes of published observations for late 2016.  I have asked the Principia team about 1b.

This is very initial ground work for Principia RSS & TRAPPIST1 & KerbalEDU in 1.4.5 so that a few highlight missions can be created to make it easier to compare the two systems in KerbalEDU e.g. Calisto & 1b.

KSP 1.4.5 TRAPPIST1 Planet Transits & KerbalEDU 1.3.1 2032 Jupiter Triple Shadow Transit 1080p captures


Considerations about Tides:


source for following images: https://www.eso.org/public/news/eso1706/
keaBUj7.jpg Xg9mXcG.jpg A0UGwBz.jpg


Detection methods:



Edited by AloE
fix links & update
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  • 6 months later...
On 12/3/2018 at 12:09 PM, AloE said:

TRAPPIST1 planet 1b is about 45 minutes early compared to published data...whereas planets 1c,1d,1e,1f,1g,1h transit within a few minutes of published observations for late 2016.  I have asked the Principia team about 1b.

On 2/5/2014 at 1:19 AM, eggrobin said:

We have rerun the TRAPPIST-1 optimization, this time with a small enough integration time step allowing us to accurately model the dynamics of the system. Thanks to @AloE for spotting the incorrectly-timed transits.
The resulting system has residuals similar to those reported by Grimm et al., with χ² = 358.79 vs. χ² = 342.29 in the paper.

Nice update work earlier this year by Principia....Time for launching craft in TRAPPIST1...Was going to make a video before posting back in Feb but the months seem to go by so quickly ;-)

(have been focused elsewhere the past few months...lol...for example: https://support.simulationcurriculum.com/hc/en-us/community/posts/360031227014--Inspire-Add-Links-Screenshots-Of-Your-Favorite-Uses-Of-Starry-Night- )

& looks like I need to verify the SLIPPIST & patch updates made & released in trappist-1 for principia fáry.zip based on:

On 4/10/2019 at 7:50 PM, eggrobin said:
On 4/10/2019 at 7:40 PM, GregroxMun said:
  • Renamed SLIPPIST-1b "Beta" to "Bravo." Dunno why I thought the NATO alphabet used Beta for "B", but a few months ago a friend of mine who's a pilot notified me that it should be Bravo, and she's right. Frankly it's more fitting like this, because if you land and launch from there... bravo.

Hm, this means we will have to update the Principia TRAPPIST-1 patch.

Opened #2129 to track this.

Edited by AloE
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  • 2 weeks later...

TRAPPIST-1 tides & your neighbor's  kitchen Induction cooktop...

while pondering some articles:

I re-read @GregroxMun's great astronomy lesson (link) to reflect more about the atmospheres & dynamics of the TRAPPIST-1 system & the adjustments made for KSP &

Created a screenshot album of the view & specs of the planets in KerbalEDU 1.4.5 alongside the lesson for quick comparison:



Edited by AloE
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  • 1 month later...
On 6/13/2019 at 12:21 AM, AloE said:

I need to verify the SLIPPIST & patch updates made & released in trappist-1 for principia fáry.zip based on:

SLIPPIST1 0.8.0 converted to TRAPPIST1 using the trappist-1 for principia fáry.zip configs appears to be working reasonably well in KerbalEDU 1.4.5 with the awareness that overtime atmosphere models can be improved...for example T at least on 1e appears to be not changing with altitude: (or Bob Kerman broke the T sensors ;-)




As more data gets published, I am thinking about what new atmosphere models might be useful to explore patched into Principia TRAPPIST1.  Many questions about approximations to make for M stars since humans have the most planet/moon climate & atm data from our G star solar system as @OhioBob makes clear in the remarkable discussion/tutorial:


Edited by AloE
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  • 5 months later...

Interesting online tools encountered while wondering about what 'Earth like photosynthesis' bacterial mats might look like to the human eye on some of the Trappist-1 worlds since "The longest wavelength yet observed in photosynthesis on Earth is about 1,015 nm (in the infrared), in purple anoxygenic bacteria." (source: The Color of Plants on other Worlds) while exploring exoplanets modeled in REX (includes the Trappist-1 system):


Stellar Spectra Visualization Tools







& an interesting "tool to convert a temperature in Kelvin into a RGB colour"

USGS radiance calculator: https://astrogeology.usgs.gov/tools/thermal-radiance-calculator/

Band & Spectral radiance Blackbody Calculator: https://www.spectralcalc.com/blackbody_calculator/blackbody.php

Solar Flux and Flux Density: https://www.ess.uci.edu/~yu/class/ess200a/lecture.2.global.pdf & https://www.ess.uci.edu/~yu/class/ess55/lecture.3.energy.pdf


Related reference topics (e.g. the Mars imaging color problem):


the Mars rovers have a bunch of tools we do not get for extrasolar planets: calibration targets

Solving the color calibration problem of Martian lander images"The true color of Mars could become known on future missions if the lander cameras were calibrated on Mars using light sources brought from the Earth.  Figure 10 illustrates three ways to do this"

& issues with calibrating the Viking images: Color Calibration of the Martian Images


Edited by AloE
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  • 4 months later...

To extend beyond the Kerbal view both into Earth's photographic sky as well as real relative star motions plus or minus a few million years in time ...There is excellent publicly funded software:

GaiaSky (link) provides a useful EDU 3D visualization of the relative location of TRAPPIST1 (SIMBAD link) = Gaia DR2 2635476908753563008  in our local region of space over time.

Motion Vector arrows show where things are headed relative to Earth's Sun, plus stellar motion becomes readily observable with high time acceleration rates. 

Aladin (link) provides simple access to beautiful color all sky survey images searchable with a great "Gaia DR2 cone search" feature.

Aladin's "Gaia DR2 cone search"  generates a layer that is easily shared with GaiaSky & TOPCAT (link) with a couple mouse clicks (right click the layer & select "Broadcast to all SAMP applications" ;-) via SAMP VOTable . 

GaiaSky will then import the table and automatically focus a star when it is highlighted by 'mousover' in Aladin.

This is all working nicely now plus can be 'bookmarked' in GaiaSky:

GaiaSky 3 (download page link)


GaiaSky & Aladin & TOPCAT SAMP with the "Gaia DR2 cone search" TRAPPIST1 & Pleiades

NASA EYES on Exoplanets (web version link) also offers an edu relevant view directly in a www browser.

Edited by AloE
added description of GaiaSky's powerful feature of relative motion with time.
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