Is the USFS project is closed because of 1.5 ?

[AstroThis]

Hi !

Like as I said in the title, is the USFS project is closed because of 1.5 ?
I really want to learn in this University but the lessons of Altaïr never begin, the lessons of Horus Lupercal go to KLP 2.7 ans I really want to know what is the Delta V, the ISP or the TWR...
If the project is plan for the 1.5, I can give some of my free time to help ! (I'll don't write any thread, I'm not qualified, I'm just a Mad Astronaut ).

I really hope that this project isn't abandonned....

 

[Horus Lupercal]

I don't think it's been abandoned entirely. It needs updating certainly now that 1.5 is finally out (part of the reason why it was paused was because we were mostly awaiting 1.5).

As for the holy trinity of ΔV, ISP and TWR, in the interim I can point you towards the thread that proceeds the USFS (The Basics) which I wrote over a year ago so it's a little dated but the basic principles are very much the same.

As always, if you've got questions or need clarifications, throw me or Altair a PM and we'll explain it in more detail.

 

[Altaïr]

Ah, sorry, I still have to do my part indeed. However, the most advanced concepts are already explained in some of my threads.

The Oberth effect: https://jmnet.one/sfs/forum/index.php?threads/advanced-techniques-the-oberth-maneuver.1215/

The gravitational slingshot: https://jmnet.one/sfs/forum/index.php?threads/advanced-techniques-the-gravitational-slingshot.1782/

Those threads were created before the USFS was a thing, that's why they are not part of it.

And of course if you have some questions, feel free to ask

 

[AstroThis]

I understood ISP and how to calculate it.
I understood how to calculate Dv but it's not very precise in my mind.... It's a sort of potential of accélération an braking before to be out of fuel ?

 

[Altaïr]

I understood ISP and how to calculate it.
I understood how to calculate Dv but it's not very precise in my mind.... It's a sort of potential of accélération an braking before to be out of fuel ?

It's by how much you can change your velocity. On a more practical point of view, here is how you can see it.
Build that rocket for example:


Then fly it straight up with no gravity/no drag:


When the fuel is depleted, look at the speed of your ship:

3143 m/s: this is (was) the delta-V of this ship. It started from 0 and ended to 3143 m/s. This is an experimental method to measure it.

Another example, when you want to perform an interplanetary transfer, when you've reached the burn point, you have a speed displayed:

It means you have to accelerate your ship by 808.3 m/s to perform the transfer. This is also a delta-V value.

In this case, this is some delta-V you have to spend. If you had the previous ship fully fueled in orbit at that point, you would have to spend 808.3 m/s from your 3143 m/s total delta-V. After that, you would have left 3143-808.3=2334.7 m/s.

In a general way, we use this to design optimal ships for a given mission. By knowing the delta-V requirements, we can design a ship that has said delta-V at its disposal (plus a margin). Of course it's possible to design a ship with more delta-V to be sure, but it also means it will be heavier and bigger. For very demanding missions it's useful to take this into account to avoid having a huge and impractical ship.

 

[AstroThis]

Thanks Altaïr !! I understood everything !!

AstroThis : Ready to calculate !