A rather boring rocket that delivers a 1t mass to low Droo orbit. But it does so with a script that can take almost any (orbit capable) rocket into the lowest safe orbit that can be efficienctly reached with unparalleled accuracy and as little dV as possible.
I've used this on everything from tiny rockets to behemoths, from ones that use 3 stages to those that do it in a single one. The results have been close to ideal every time. The script includes some parameters (top left, with explanatory comments) that can allow fine tuning of performance, but playing with them is not necessary for it to work with any sensible craft.
The script does multiple things during launch:
• Automatically stages as fuel runs out.
• Maintains heading to have lowest inclination possible for the launch site.
• Goes straight up until the craft is out of the thickest part of the atmosphere, then turns down range to initiate the ideal gravity turn estimated for its TWR (tuneable).
• Continues this gravity turn by keeping to prograde, smoothly switching from tracking surface to orbital prograde.
• Adjusts the throttle to prevent excessive loss to atmospheric drag (tuneable).
• Continues doing this until the apoapsis is above the minimum safe altitude (tuneable).
• Calculates live how long the circularization burn will take, and by how much time the apoapsis will be pushed back while this burn is happening.
• Uses this prediction to start the circularization burn as late as safely possible to have the lowest, most accurate, and most efficient insertion.
• Controls the throttle to "surf" the apoapsis and complete the circularization burn smoothly just as it is reached, taking into account engine spooling time (tuneable).
• Reports what is happening at every point through the flight log so you can sit back and enjoy the automated show.
For the rocket uploaded, the screenshots show the different stages of going from the desert launch pad to orbit. The results shown are typical: it takes under 4.8 km/s of dV to end up with an apoapsis and periapsis within 1km of each other around 85km ASL.
UPDATE 1.11: Improved presentation of code to make it easier to integrate your own customization to the launch (ie, retracting landing legs, ejecting side tanks) as launch thresholds are reached, and removed empty input fields in vizzy (thanks to @Ambarveis). Actual performance unchanged.
GENERAL INFO
- Created On: Windows
- Game Version: 1.0.909.1
- Price: $1,585k
- Number of Parts: 7
- Dimensions: 19 m x 2 m x 2 m
PERFORMANCE
- Total Delta V: 5.2km/s
- Total Thrust: 265kN
- Engines: 2
- Wet Mass: 13,891kg
- Dry Mass: 4,155kg
STAGES
| Stage | Engines | Delta V | Thrust | Burn | Mass |
|---|---|---|---|---|---|
| 1 | 1 | 2.1km/s | 209kN | 1.6m | 13,891kg |
| 2 | 1 | 3.1km/s | 56kN | 3.0m | 4,536kg |
2 Comments
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0 chrisic33 months ago
Really appreciate the work you put into this. I have been searching for the best way to learn how to figure all of this out, and learn what needs to be figured out.
Do you have any resources or suggestions on how to start learning this material from scratch? I’m understanding bits and pieces, but there’s still a lot I don’t understand.
Basically, I want to learn how to design crafts based on needs, and based on those crafts, how to figure out the needed orbits and trajectories and how to get it there. If that makes sense.
@chrisic3 When it comes to designing ships for a mission, deltaV is really what matters. Landing / taking adds complexity, but otherwise dV is key. People have made dV maps that show how much you need to get between bodies and into typical orbits. Make sure your craft has enough dV for the journey you want it to make (with a bit to spare), and you ought to be fine. For mission planning, Hochmann transfer is the thing to google: there's a lot of older stuff written out there in the early days of Kerbal that is still applicable.
Learning how all this works is commendable! Wikipedia is pretty good actually and will cover most of what you need to know, but to be honest, it can be hard to know what it is that you need to learn. As a starter, their article on Orbital Mechanics is pretty good and will point you towards more detail stuff. Combining that with an intuitive feel gained by playing Juno or Kerbal is a good mix.
But anything technical gets mathsy quickly: without at least a high school understanding of algebra and physics I suspect not much of it will make sense. Not that there's anything stopping you from learning such maths and physics yourself, whether you're not in high school yet or graduated decades ago and forgot most of it!