Stock ISS Approximation, [WIP]

Pi_ · August 29, 2017

Disclaimer: I was originally going to call this project an "ISS Replica". I had already built Zarya, Node 1 Unity, and the first two PMA's... and then I discovered the following thread. After seeing what those guys did, I decided to call this an "ISS Approximation". If you're at all interested in a stock version of the ISS, I encourage you to check out what they built. It's pretty amazing!

My first attempt Stock ISS was built back in v0.23.5, and back then the high part count made the game lag very badly. I knew that part count would not be as big an issue this time. However, due to my lack of time (and skill), I had planned to leave out certain elements such as robot arms, CETA cart, stowage platforms, etc. But I am building in docking ports to possibly add some elements later. Also, this project will be launched with non-IRL rockets, and assembled with a purpose built Tug. Space Shuttle not modeled, sorry EJ :sticktongue:

My goal was to find some balance between appearance & functionality. For example, I won't have a working Canadarm, but Zvezda is able to perform orbital reboosts (although it's not needed in KSP). EVA's will only be possible from IRL airlocks, all other hatches are covered / blocked. Crewmembers are transferred to station and returned to Kerbin via a functional Soyuz, however it only has two seats instead of three. I'm streaming the fabrication & assembly sessions on Twitch, but I don't feel the need to document this project with YouTube videos... that's what this thread is for. And frankly, I have no experience making videos.

ISS Approximation, KSP v1.3.0, sandbox stock parts, no mods

Station will be assembled to it's config as of JUN 2017, according to the historical timeline... mostly. Relocation of some elements will be skipped, i.e. P6 Truss. Future station configurations will be addressed as necessary, i.e. deorbiting Pirs, adding IDA-3 & Russian modules.

Reference Sources: https://spaceflight.nasa.gov/gallery/images/station/assembly/ndxpage1.html

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

https://upload.wikimedia.org/wikipedia/commons/c/ca/ISS_configuration_2017-06_en.svg

https://upload.wikimedia.org/wikipedia/commons/2/25/Russian_Orbital_Segment.png

https://www.youtube.com/watch?v=vgfWH3g9kpY

https://www.youtube.com/watch?v=ZYUpdG1tKH0

https://www.youtube.com/watch?v=VopaBsuwikk

https://www.youtube.com/watch?v=UgaC1fmF5ao

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Stream 01, 16 AUG 2017

Module Name, Part Count, Mass (dry)

Launch 01, Zarya FGB, 36, 7.9t
Launch 02, Node 1 Unity, 10, 3t - PMA 1, 6, 1.4t - PMA 2, 6, 1.4t
Launch 03, Zvezda Service Module, 34, 11.9t
Launch 04, Soyuz/Progress, 19, 4.4t
Total: Parts = 111, Mass = 30t

My first ISS build (KSP v0.23.5) contained several reaction wheels. It was fairly stable in orbit when other ships docked to it, also when the whole station rotated (in any axis) using SAS. This time, not so much. So someone in my stream suggested autostruting, and it seemed to work. I've never used autostruts since they were added to the game. If I built something that needed struts, I did it the old fashioned way.

Having not used it before, I figured it would be best to autostrut to the center of mass of the completed station... which roughly would be Node 1 Unity. Well, Node 1 was not the first station module launched IRL, nor in this project. And apparently when assembling a station in orbit, the first module launched becomes the root part. So I started over by deleting what I had already assembled in orbit (the first 4 launches). Then I went to the spaceplane hanger where my assembled mockup is. Then I rerooted the assembled mockup to Node 1, then cheated it back into orbit. Sorry, I didn't feel like doing those launches & dockings again.

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Stream 02, 23 AUG 2017

Launch 05, Z1 Truss, 29, 1.6t - PMA 3, 6, 1.4t
Launch 06, Destiny Lab, 12, 6.5t
Total: Parts = 158, Mass = 39.5t

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Stream 03, 27 AUG 2017

Launch 07, Quest Airlock, 15, 2.2t - Pirs Docking Compartment, 9, 1.6t
Total: Parts = 182, Mass = 43.3t

selfish_meme · August 30, 2017

Nice, part count is always going to be the issue unless you use welding for the ISS

Pi_ · September 1, 2017

Stream 04, 31 AUG 2017

Module Name, Part Count, Mass (dry)

Launch 08, S0 Truss, 46, 6.1t
Launch 09, S1 Truss, 42, 6.3t
Launch 10, P1 Truss, 42, 6.3t
Launch 11, Node 2 Harmony, 11, 4.0t - Columbus Lab, 20, 4.0t
Total: Parts = 343, Mass = 70.0t

So far, every launch ( with the exception of Zvezda) has been performed with the lifter shown below. Consisting of two Twin Boar boosters, with no fuel lines feeding the orange tank. I do a roll program starting around 500 meters altitude. The roll goes a bit past the 45 degree radial on the navball, and then I do an inclination correction once in orbit The correction is normally no more than 3 or 4 degrees. The boosters jettison & ignite the Mainsail under the orange tank. The orange tank jettisons & ignites the Poodle under the X200-16 tank. Shown below is the fairing for the S1 & P1 Truss segments. Of course for the S0 Truss, the fairing bulged in the middle to accommodate the supports which attached to the top of the Destiny Lab.

The Poodle stage doubles as a kicker for the rendezvous, and an assembly tug. The first two tugs remain with the station until assembly is complete. The others are deorbited after attaching their payload. I had to fabricate a truss launch adapter (between the tug & truss), because when attaching docking ports to that Tri Coupler, I could not get all three to align with the three ports on the truss segment... it performed very nicely.

On the forward face of the SO Truss to the left is an empty docking port, there is also one just below it in this image on the forward side of the Quest Airlock. Depending on how part count causes the game to lag, these ports will hold the Mobile Base System (not to be confused with the CETA Cart), and the External Stowage Platform #2.

In addition to skipping the initial P6 solar array segment, this is the 2nd major deviation from the historical assembly timeline. IRL, both inner sets of solar arrays (P3/P4 & S3/S4) were installed before Node 2 Harmony & the Columbus Lab. I'm still thinking about how I want to build the solar trusses, but they will be next, and then I'll be back on the timeline

Port & Starboard navigation lighting was purely for fashion... not on the real ISS :cool:

Something I didn't know before doing research for this project... the whole integrated truss structure is attached to the top of the Destiny Lab. I always thought is was attached to the Z1 Truss. But actually there is enough room between them for EVA astronauts to pass through that gap. And they often have, as can be seen in the animations linked in the reference sources in my first post.

Pi_ · September 4, 2017

Stream 05, 02 SEP 2017

Module Name, Part Count, Mass (dry)

Launch 12, P345 Truss, 40, 6.6T
Launch 13, Solar Panel Half, 19, 4.1t
Total: Parts = 402, Mass = 80.7t

IRL, the P3 & P4 truss segments (as well as S3 & S4) were built as a single unit, and the P5 & S5 segments were separate units installed later. I combined segments 3-4-5 into a single unit. And while I was at it, I built the P6 & S6 truss segments.

P & S 3-4-5 Unit

P & S 6 Unit

My solar panel design is a two piece unit. The 1st piece is attached to the truss structure in orbit, then the 2nd piece is attached to the 1st. However, this two piece unit is only one half of a complete "north-south" solar panel.

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Not Streamed, 03 SEP 2017

Launch 14, Solar Panel Half, 19, 4.1t
Total: Parts = 421, Mass = 84.8t

Pi_ · September 5, 2017

Stream 06, 04 SEP 2017

Module Name, Part Count, Mass (dry)

Launch 15, S345 Truss, 40, 6.6t
Launch 16, Solar Panel Half, 19, 4.1t
Launch 17, Solar Panel Half, 19, 4.1t
Total: Parts = 499, Mass = 99.2

Pi_ · September 6, 2017

Not Streamed, 05 SEP 2017

Module Name, Part Count, Mass (dry)

Launch 18, P6 Truss, 27, 4.8t
Launch 19, S6 Truss, 27, 4.8t
Launch 20, Solar Bundle (Panel Half x 4), 76, 16.4t
Total: Parts = 629, Mass = 125.2

Since Node 2 & Columbus are already in place, I decided to complete all the solar arrays before continuing with the Japanese lab. Both P6 & S6 Truss segments were installed first. Then the remaining solar panels were launched in a bundle and parked in orbit near the station. Yeah, the large fairing on the bundle rocket made the ascent a bit tricky to control. Also, somewhere around launch #14 or 15 I began to see the MET clock digits flashing yellow. There is no lag while working at the station, but there is brief pause on approach to rendezvous when entering physics range. My computer is an I7 - 16GB Ram - GTX 970. It will be interesting to see what happens as the part count grows.

Pi_ · September 11, 2017

Stream 07, 09 SEP 2017

Module Name, Part Count, Mass (dry)

Launch 21, JLM (Japanese Logistics Module), 7, 1.3t
Launch 22, Kibo (JEM-Japanese Experiment Module), 17, 7.6t
Launch 23, JEF (Japanese Exposed Facility), 35, 2.3t - Poisk (MRM-2), 9, 1.6t
Launch 24, Node 3 Tranquility, 11, 4.0t - Cupola, 4, 1.9t
Launch 25, Rasvet (MRM-1), 17, 2.0t - Leonardo PMM, 8, 3.8t
Total: Parts = 737, Mass = 149.8t

At this point IRL, the next component installed was the P6 Truss (which contained the final solar array). However, the P6 solar array install is already completed as seen in my previous post. Continuing on the IRL assembly timeline, the next two components installed were the Japanese Exposed Facility ("Front Porch"), and the Russian MRM-2 module (Poisk). Since these two components were relatively low mass, I combined them into the same launch. The landing leg on the Japanese Lab is to approximate the robotic arm.

As mentioned before, the ExPRESS Logistics Carriers & Alpha Magnetic Spectrometer are being skipped. However, attachment points are in place for future installation of these components... depending on the game lag caused by the high part count. Following the installation of all components shown in this post (launches 21-25), the MET clock is steady yellow. The lag is around 2 seconds of real time per 1 second of game time.

To make the station what I consider as "complete" to what's currently in orbit IRL, the following components will be added: Bigelow Expandable Activity Module (BEAM), 3 more Soyuz/Progress craft, International Docking Adapter (IDA 2). Following that, there are more components scheduled to be installed in the future IRL... one more IDA (which is only a few parts), and four more Russian modules. So, the ESP's & ELC's are on hold indefinitely.

Which brings us back to the IRL assembly timeline (project launch #24). IRL, Node 3 Tranquility & the Cupola where launched together, with Cupola attached to the top end of Tranquility. After Tranquility was installed to Node 1 Unity, the Cupola was moved to the nadir port of Tranquility. I launched with Cupola already attached in it's final location. However, it does have it's own docking port instead of being hard attached to Tranquility, along with a grapple fixture to allow it to be moved in the event it is ever moved in the future IRL. The 2nd Cupola was included only for balance during the launch & ascent (fairing not shown), it was decoupled and deleted after reaching orbit. The Cupola in KSP has a larger diameter than the real thing. But as I don't use mods (Tweakscale), we use what's available.

Next on the IRL timeline were the Russian MRM-1 module (Rasvet), and the Permanent Multipurpose Module (Leonardo-PMM). These two components are combined into the same launch (fairing not shown).

IRL, Leonardo was originally installed to the nadir (bottom/Earth facing) port of Node 1 Unity. Then later it was relocated to the forward facing port of Node 3 Tranquility. I installed to it's final location, which required a handoff from the launch tug to the station's assembly tug via the grapple fixture on Leonardo's nadir side. Because with Leonardo still attached to the launch tug, there is not enough clearance from Kibo.

Pi_ · September 17, 2017

Not Streamed, 14 SEP 2017

Original combo Soyuz/Progress (Launch #04) replaced, and it's part count/mass subtracted from station totals. Separate Soyuz & Progress craft designed. New Progress craft docked to station.

Previous Total: Parts = 737, Mass = 149.8t
Subtracted: Parts = 19, Mass = 4.4t Original Soyuz/Progress (Launch #04)
Adjusted Total: Parts = 718, Mass = 145.4t

Module Name, Part Count, Mass (wet)

Launch 26, Progress, 20, 5.0t
Total: Parts = 738, Mass = 150.4

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Stream 08, 15 SEP 2017

Module Name, Part Count, Mass (wet)

Launch 27, Soyuz, 26, 5.1t
Launch 28, Progress, 20, 5.0t
Launch 29, Soyuz, 26, 5.1t
Launch 30, BEAM (Bigelow Expandable Activity Module), 6, 0.6t (dry) - IDA 2, 3, 0.2t (dry)
Total: Parts = 819, Mass = 166.4t

My original Soyuz/Progress craft from Launch #04 was actually a single vehicle. But over the whole fabrication & assembly process, there was a nagging thought in the back of my mind because that original design only had two seats. This prompted me to decommission the combo design in favor of two separate craft... and this time the Soyuz would include a 3rd seat. Since the IRL Progress is solely a resupply craft, it's redesign included a larger fuel tank, standalone RCS tank, probe core for remote control, and no seats.

For the Bigelow Module, it was pretty obvious a fairing would best approximate the appearance and relative scale. It is the most recent element to be installed on the station IRL (April 2016), which brings us to the current state of the historical assembly timeline.

Following installation of the BEAM, the entire station crew celebrated with an EVA party :cool:

Parting Shots

Port (Left) side

Starboard (Right) side

Aft (Rear) end

Forward (Front) end

Nadir (Bottom/Earth Facing) side

Zenith (Top/Space Facing) side

I've really enjoyed doing this project over the last month. After researching many articles and videos, I've certainly gained a new appreciation of the massive effort that went into building the real life International Space Station (both in orbit & on the ground).

More to come?

In 2009, NASA had stated plans to end the ISS program and deorbit the ISS in early 2016. This was in accordance with the then-President Bush's policy. President Obama announced new policy in 2010, extending the program through 2020. However the current plan is to prolong operation of the ISS until 2024.

According to a 2009 report, RKK Energia is considering methods to remove some modules of the Russian Orbital Segment when the end of mission is reached. Those modules will be used as a basis for a new station, known as the Orbital Piloted Assembly and Experiment Complex (OPSEK).

The modules shown below are still planned to be added to ISS at some point. However, engineering problems have already pushed back their deployment several years. It is becoming less likely that they will be completed for installation on ISS before it is decommissioned. It's my opinion that when completed, they will not be installed on ISS at all. But rather will be used to begin the new Russian station.

Nauka - Multipurpose Laboratory Module (MLM) (scheduled 2018)