[1.8.1 - 1.12] Photon Sailor 1.7.1 (now with background processing)

[FreeThinker]

Photon Sailor aims to create a realistic photon-sailing experience in KSP. A photonsail, also known as solar sail or laser sail, allows a spacecraft to propel itself using radiation pressure from the sun or laser transmitters, removing the need to carry any reaction mass and simply using the deflection of photon energy to provide thrust.

The acceleration gained from solar radiation is extremely small but can be applied over a long period of time to reach extremely high speeds, given a large enough sail and a payload of low mass. Besides being propelled by the photons emitted by the sun, it can also be propelled by photons emitted by KSC beamed power station or by (KSPIE) beamed power transmitters, allow ejecting solar sail to be launched at much higher speeds than with using only solar energy.

Spoiler

Notice a faint beam of light pushing it forward by 15 N

Photon sails function both under real time as and non-physical timewarp, allowing for them to be useful for interplanetary travel. Photonsails must operate mainly outside the proximity of atmospheres (> 400 km) which due to their large sail surface area are much subject to the effects of drag which are accurately simulated. The sail can also use drag as an effective means of orbital capture

 

 

Download Photon Sailor Version 1.7.3 for Kerbal Space Program 1.8.1 - 1.12

Older versions can be found here

source code: GitHub

If you want to chat about Photon sailing you can do it at our KSP Interstellar Discord Server

Supported Mods

CKAN

Recommended mods which improve play experience:

License:

Credits

SasquatchMarmalade  for creating the Solar Sail part

@Fractal_UK For for initial creation of solar sail code

@mrsolarsail For improving the solar sail code

Photon Sail Control

To help you with altitude control, the part interface contains several useful indicators like Periapsis, Apapsis and Orbital Diameter Change

Understanding Solar Sails

Changing orbits with a solar sail is counter-intuitive, since the forces at work are significantly different to both rockets, and sailing ships.

The simplest way to understand and experiment with this is to leave Kerbin's sphere of influence, and put the sail in a solar orbit with conventional rockets. It is possible to use sails in low planetary orbits, but there are several complexities here - it becomes more difficult to align the sail, and the planet tends to get in the way.

In a solar orbit, there will be two vectors acting on the craft. One vector will push the sail directly away from the sun, and the other will be controlled by the deflection of the sail - most efficiently at an angle of 45 degrees to the radial vector.

Travelling away from the sun:

(45 degrees retrograde)

Travelling towards the sun:

(45 degrees prograde)

(Images from SolarSailWiki, by Ben Diedrich, under a Creative Commons Licence)

Since this will take a long time to take effect, the sail may complete several solar orbits before reaching it's destination. Therefore, this will require holding a heading, time warping, re-adjusting the heading, and time warping again.

It's possible to consider the above in terms of "reflecting the light in the intended direction of thrust", since lowering an orbit would require thrusting with a rocket oriented to the retrograde vector, or equally the exhaust oriented towards the prograde vector.

Configuration/Modding

Spoiler

PhotonSailor partmodule has several hidden fields that can be override

Yo increase Aperture increase upgrades:

kscLaserApertureBonus0 = 50
kscLaserApertureBonus1 = 0
kscLaserApertureBonus2 = 0
kscLaserApertureBonus3 = 0
kscLaserApertureBonus4 = 0
kscLaserApertureBonus5 = 650
kscLaserApertureBonus6 = 0
kscLaserApertureBonus7 = 0

kscLaserApertureName1 = KscApertureUpgradeA
kscLaserApertureName2 = KscApertureUpgradeB
kscLaserApertureName3 = KscApertureUpgradeC
kscLaserApertureName4 = KscApertureUpgradeD
kscLaserApertureName5 = KscApertureUpgradeE
kscLaserApertureName6 = KscApertureUpgradeF
kscLaserApertureName7 =

 

Now what is missing are actual part Upgrades

To Create them, edit and existing upgrade.cfg  or create a new file and add something like this

PARTUPGRADE
{
	name = KscApertureUpgradeA
	partIcon = dielectricPhotonSail
	techRequired = cuttingEdgeSolarTech
	entryCost = 0
	cost = 0
	
	title = upgrade KTC aperture
	manufacturer = #autoLOC_501627 //#autoLOC_501627 = Jebediah Kerman's Junkyard and Spacecraft Parts Co. 
	description = increase aperture KTC Laser Array by 50m
}

PARTUPGRADE
{
	name = KscApertureUpgradeE
	partIcon = dielectricPhotonSail
	techRequired = exoticSolarTech
	entryCost = 0
	cost = 0
	
	title = upgrade KTC aperture
	manufacturer = #autoLOC_501627 //#autoLOC_501627 = Jebediah Kerman's Junkyard and Spacecraft Parts Co. 
	description = increase aperture KTC Laser Array by 650m
}

 

 

The same applies for Power upgrades:
 

kscPowerUpgdradeName1 = KscPowerUpgradeA
kscPowerUpgdradeName2 = KscPowerUpgradeB
kscPowerUpgdradeName3 = KscPowerUpgradeC
kscPowerUpgdradeName4 = KscPowerUpgradeD
kscPowerUpgdradeName5 = KscPowerUpgradeE
kscPowerUpgdradeName6 = KscPowerUpgradeF
kscPowerUpgdradeName7 = KscPowerUpgradeG

kscLaserPowerBonus0 = 50
kscLaserPowerBonus1 = 350
kscLaserPowerBonus2 = 600
kscLaserPowerBonus3 = 1000
kscLaserPowerBonus4 = 2000
kscLaserPowerBonus5 = 4000
kscLaserPowerBonus6 = 12000
kscLaserPowerBonus7 = 30000

 

The location of the KTC laser array can be override as well

 

kscLaserLatitude = -0.13133150339126601
kscLaserLongitude = -74.594841003417997

2

 

Change Log

Spoiler

Version 1.4 for Kerbal Space Program 1.4.3

Released on 2018-07-14

• Compiled against KSP 1.4.3
• Added Improved Beamed Power Ray graphic effects
• Added Improved Thermal Dynamics simulation on sail
• Added Atmospheric Laser absorption
• Added support ofIgnore Heat Cheat
• Added mass reduction based on unlocked Material and CTT Construction techs
• Balance: reduced minimum tech requirement photon sails
• Fixed missing ray texture

Version 1.3 for Kerbal Space Program 1.4.4

Released on 2018-07-08

• Reduced memory , install size and loading time
• Improved User interface
• Added 2 TW KSC ground based long infrared laser
• Added Absorption based sail heating with overheating safeguard

Version 1.2 for Kerbal Space Program 1.4.3

Released on 2018-07-02

• Added support for Textures Unlimited
• Added Aluminum Photon Sail
• Added support for Kopernicus with multiple stars
• Changed texture Gold Photon Sail to Gold color

Version 1.1.1 for Kerbal Space Program 1.4.3

Released on 2018-06-30

• Added support for AVC
• Added support for CKAN
• Added Support for Kopernicus multiple star systems
• Added improved atmosphere drag simulation
• Added atmosphere Space Drag heating
• Added Drag coefficient display
• Fixed solar sailing thrust which was to high
• Fixed solar sailing animation responsiveness
• Fixed short short laser beam animation

 

Research Sources

Spoiler

https://arxiv.org/ftp/arxiv/papers/1604/1604.01356.pdf

https://arxiv.org/pdf/1701.08803.pdf

http://breakthroughinitiatives.org/i/docs/170919_bidders_briefing_zoom_room_final.pdf

 

 

Edited June 28, 2021 by FreeThinker

[ARS]

Awesome! Will try it out! 

I always wanted to build a solar sailer in KSP. One question, does the sail also function as solar panel too? Or purely for propulsion?

Edited June 27, 2018 by ARS

[Jesusthebird]

Cool. Ill have to try this out sometime. Not prying just wondering. Will the sail model go through any revisions?? It looks a lil 2Dish. Would look really neat if it was more like a kite. Or if the quarters could rotate to 45degrees. Googling "photon sail" gives lots of examples. Congratz on the release too!

[FreeThinker]

6 hours ago, ARS said:

Awesome! Will try it out! 

I always wanted to build a solar sailer in KSP. One question, does the sail also function as solar panel too? Or purely for propulsion?

It has some build in film solar cells, enough to keep a probe powered. You can scale it down up or down to cube size.

30 minutes ago, Jesusthebird said:

Cool. Ill have to try this out sometime. Not prying just wondering. Will the sail model go through any revisions?? It looks a lil 2Dish. Would look really neat if it was more like a kite. Or if the quarters could rotate to 45degrees. Googling "photon sail" gives lots of examples. Congratz on the release too!

Currently the is only one model without any upgrades but I plan to add more diversity in the future.

[FreeThinker]

Photon Sailor should now be available on CKAN. Could anyone verify?

[OldLost]

I see it there now.

[FreeThinker]

A new release, Photon Sailor 1.1.1 can be downloaded from here

Changelog:

* Added support for AVC

* Added support for CKAN

* Added Support for Kopernicus multiple star systems

* Added improved atmosphere drag simulation

* Added atmosphere Space Drag heating

* Added Drag coefficient display

* Fixed solar sailing thrust which was to high

* Fixed solar sailing animation responisveness

* Fixed short short laser beam animation

 

Edited June 30, 2018 by FreeThinker

[FreeThinker]

Version 1.2 for Kerbal Space Program 1.4.3 can be downloaded from here

Released on 2018-07-02

• Added support for Textures Unlimited
• Added Aluminum Photon Sail
• Added support for Kopernicus with multiple stars
• Changed texture Gold Photon Sail to Gold color

[Andi K.]

2 hours ago, FreeThinker said:

Added support for Textures Unlimited

This makes me happy 

[FreeThinker]

I'm working to add a feature which will allow you to rent high power laser beam from KTC without KSPIE installed.

For the right price, this should help you get your photon sail blasted into outer space.

Edited July 4, 2018 by FreeThinker

[The-Doctor]

Oh wow, is this what you've been working on secretly?

[FreeThinker]

5 hours ago, The-Doctor said:

Oh wow, is this what you've been working on secretly?

Not realy, I have been saying I wanted to implement this for quite some time. This mod is also an attempt to modularize KSPIE which due to it complexity and size many people seem to afraid to even try.

[Gordon Dry]

KSP-AVC says "1.3"

[FreeThinker]

Version 1.3 for Kerbal Space Program 1.4.4 can be downloaded from here

Released on 2018-07-08

• Reduced memory usage, install size and loading time
• Improved User interface
• Added 2 TW KSC ground based long infrared laser
• Added Absorption based sail heating with overheating safeguard

Edited July 9, 2018 by FreeThinker

[FreeThinker]

9 hours ago, Gordon Dry said:

KSP-AVC says "1.3"

Yes I need to get used to the applied AVC version update  mechanism which is to link to the Github avc file rather than the generated AVC file at the AVC hosting site which is believed to be unreliable

Edited July 9, 2018 by FreeThinker

[FreeThinker]

Notice that in science or campaign mode, the KSC Laser beamed power transmitter only gets active after unlocking the CTT Science Energy tech nodes which also unlock KSPIE beamed power transmitters. There are 6 tech levels each increasing the power of the KSC laser power relative to the amount of science it cost to unlock it.

[FreeThinker]

I wonder if anyone could help me establish the correct mass for the solar sail because it has a much higher mass than the one required for interstellar mission

Quote

The two scientists based their calculations on a space probe weighing less than 100 grams in total, which is mounted to a 100,000-square-metre sail, equivalent to the area of 14 soccer fields.

100 gram for 100,000-square-metre sounds insane to me, but perhaps it is possible under certain conditions

[The Minmus Derp]

Can it work as a laser sail like Starshot?

[FreeThinker]

14 hours ago, The Minmus Derp said:

Can it work as a laser sail like Starshot?

Yes it can.  In the next release, sail mass are significantly decreased allowing you to shoot a cube sized light-sail at 6% of the speed of light. The main limiting factor is heat absorption.

Edited July 12, 2018 by FreeThinker

[The Minmus Derp]

6 hours ago, FreeThinker said:

Yes it can.  In the next release, sail mass are significantlu decreased  allowing you to shoot a cube sized light-sail at 6% of the speed of light. The main limiting factor is heat absorption.

Ah. Goodiegoodie. Initiating ignore max temp cheat now.

[FreeThinker]

1 hour ago, The Minmus Derp said:

Ah. Goodiegoodie. Initiating ignore max temp cheat now.

that won't work because it will not request more power than it can handle. The Gold Photon Sail is able to handle all power transmitted from KSC, the aluminium sail is not. To compensate, in the next release, I will add support for ksp ignore heat cheat.

Edited July 12, 2018 by FreeThinker

[The Minmus Derp]

Initiating ignore geeforse now. ;p

[FreeThinker]

Next release will have improved Beamed laser animation

The intensity of the laser scales with the strength of the laser beam.

[JoE Smash]

Why does this have the dependency of Community Tech Tree on CKAN? I DO NOT want Community Tech Tree just for this mod....or AT ALL....

Can you remove it please?

[FreeThinker]

10 hours ago, JoE Smash said:

Why does this have the dependency of Community Tech Tree on CKAN? I DO NOT want Community Tech Tree just for this mod....or AT ALL....

Can you remove it please?

It will still fully function in Sandbox mode, only in campaign or science mode, there is a difference. I guess I could made it a recommendation rather than a dependancy. But why are you not willing to install CTT?

Edited July 14, 2018 by FreeThinker