Challenge Prelude III Ariel to Miranda

[T1234]

Start from Prelude Ariel and land at Prelude Miranda.I managed with XR2 expert with 2 fuel tanks with 1.2 km/s to spare.Use DGIV if you wish. Requires preludeIII uranus addon.

View attachment XR2Ariel2MirandaChallenge.zip


Scoreboard

Top |

XR2 Ravenstar​

| Pilots

#​

|

Name​

|

Fuel left​

#1 |

Castor​

|

4537.4​

#2 |

T1234​

|

3393.3​

#3 |

none​

|

0000.0​

#4 |

none​

|

0000.0​

#5 |

none​

|

0000.0​

 

[dgatsoulis]

Nice scenario, I like moon-hopping missions on the outer planets. The addition of the Prelude base, (a base that's actually a vessel), makes it slightly more challenging during the Miranda approach/base alignment phase.

It would be better if you also provided the config file (.xrcfg) for the XR2, so everyone who tries your scenario uses the same configuration.

Just to give an idea of what kind of Delta-V expenditure to expect from an optimal flight:

[Hohmann Transfer with
Hyperbolic excess velocity for Ariel departure: 0.56 km/s
Hyperbolic excess velocity for Miranda arrival: 0.84 km/s]

Launch to Ariel Low Orbit (~10km) = 0.4 km/s
TMI burn = 0.4 km/s
MOI burn (5 km alt) = 0.75 km/s
Landing at Miranda = 0.15 km/s

Total: 1.7 km/s (all the burns have been rounded to the next "ten").

Including a generous 10% additional Delta-V for corrections and alignments (and rounding up) this mission can be easily done with 1.9 km/s of Delta-V in the tanks of the landed Ravenstar.

With expert settings:
-ISP setting = 0
-Internal Tank capacity = 50%
-APU for 33 mins
-LOX internal tank 182kg (7 days)
-Full crew
-CHM loaded
-No other cargo
you can get 1.9 km/s of Delta-V, by loading the Main Tank at 44.44% and the RCS tank at 10% (2,976.4+80.4 = 3053.8 kg total fuel).
The flight lasts slightly less than a day.

 

[T1234]

Forum will not let me upload config file.Are you using transx or IMFD?,I used around 7km/s of fuel with a 1.3 km/s mcc burn!, went close to Uranus and encountered Miranda on apogee,thinking that would slow me down,I don't think that is a Hohmann transfer?

 

[dgatsoulis]

Forum will not let me upload config file.

Zip them together and attach the zip on the post. Make sure you create the correct directory structure, so the participants can run the scenario as intended, by simply unzipping the file in their Orbiter root directory.
Example:
On your desktop, create a directory named Scenarios and place the scenario in there.
Again on the desktop, create a directory named Config and place the .xrcfg file in there.
Select both directories (Scenarios and Config) and zip them together.
Then click on the attachments button of the O-F post and upload the zip file as an attachment.

Are you using transx or IMFD?

Both. The initial setup with TransX, because IMFD was a little "jumpy" at the point of the minimum dV transfer. (It was right at the node, so IMFD was trying to flip it around).
Once I was in Ariel orbit, I handled the burn with IMFD's Delta Velocity and Map programs linked together. 6 hours away from Miranda, I performed a ~ 50 m/s MCC, but I had to wait until I was closer for the alignment burn. That cost an additional 100 m/s. Total corrections 150 m/s. I could have avoided the second MCC if IMFD's Map program could target landed vessels.

I used around 7km/s of fuel with a 1.3 km/s mcc burn!, went close to Uranus and encountered Miranda on apogee,thinking that would slow me down,I don't think that is a Hohmann transfer?

Yep, definitely not a Hohmann. A Hohmann transfer has the apoapsis at the departure body and the periapsis at the target body (or vice-versa), with a transfer of 180° around the central body.
Miranda and Ariel are zipping around Uranus at high velocities, so anything non-Hohmann-like, will cost significantly more.

 

[T1234]

Like this?

 

[jas4500]

Glad to see I started a good challenge idea. Coping without the autopilot was pretty difficult, but I was able to do it, but now I need to try it with the expert settings.

 

[dgatsoulis]

Like this?
Scenarios.zip (3.3 KB
zip.gif Config.zip (12.6 KB)

No. There are several mistakes, first with the zip file itself, second with the config file you used and finally with your definition of "expert" settings.
I'll adress them one by one.
I hope I don't sound patronizing, I 'm just showing you how to create a correct challenge, that people will enjoy trying out.
It will also be the same for everyone without messing up the settings of other XR2 scenarios they might have.

Let's start with the zip file:

Example:
On your desktop, create a directory named Scenarios and place the scenario in there.
Again on the desktop, create a directory named Config and place the .xrcfg file in there.
Select both directories (Scenarios and Config) and zip them together.

That means click on one, press CTRL and click on the other. Now that they are both selected, right-click on either of them and add them to a zip file. Name the file whatever you want, (MyChallenge.zip, XR2Ariel2Miranda.zip, whatever.zip, etc.). In general it is better to give the zip file a unique name that makes it easy for the receivers to know what challenge they've downloaded.

Now about the config file:
What you posted was the global configuration file for the XR2. If anyone uses that, it will change the settings for the Ravenstars in all their scenarios, not just your challenge.
Here is how you create a config file that only applies to a single scenario:

Open the scenario file and give the Ravenstar a unique name. For example in this challenge a good name would be XR2_Ariel2Miranda. Make sure that you also change the names of the payloadbay and cargos, if you have any.
Don't forget to write a short description in the BEGIN_DESC - END_DESC section, explaining to people what they are supposed to do in this scenario.

Once that's done, go to your config directory and create a file named XR2_Ariel2Miranda.xrcfg. Copy the contents of your XR2RavenstarPrefs.cfg and paste them in the XR2_Ariel2Miranda.xrcfg file. Save and exit.
If the name of the Ravenstar in a scenario, and the name of the .xrcfg file in the Config directory match exactly, the XR2 in that scenario will bypass the global configuration file and use the settings of the .xrcfg file.

Finally, about the "expert" settings you've supposedly used.
This of course is rather subjective, but I believe that "expert" settings should mean "the hardest possible setting in every option, without using the cheat codes".

In your config file you have:

RequirePayloadBayFuelTanks=0 --This should be set to "2" if you want "expert" settings.

MainFuelISP=0 --Correct

SCRAMFuelISP=1 --No scram used in this scenario, so it doesn't really matter, but it should be set to "0" for expert settings in other scenarios.

LOXLoadout=1 --"0" is the expert setting.

APUFuelBurnRate=3 -- "5" is the expert setting.

DoorStressDamageEnabled=0 --"1" is the expert setting.

EnableManualFlightControlsForAttitudeHold=0 --"1" is the expert setting.

CoolantHeatingRate=2 --You disabled the coolant temperature. "1" is the expert setting.

The ones I haven't mentioned were already set at their correct "expert" setting.

Again, this is rather subjective, after all one can use the cheatcodes to make the Ravenstar even harder -not easier- to fly, but as far as using the expert setting options, without touching the cheatcodes, I think that everyone would agree that those are "expert" settings.

I have attached a zip file below with all the corrections I've mentioned. The Ravenstar is fully fueled and has LOX for 7 days.

Anyone that downloads the file, only has to unzip it in their Orbiter root directory and he or she will fly the mission with exactly the same settings as anyone else, without messing up their global Ravenstar configuration file.
This also creates a level playing field, so any two Orbinauts can compare how they did against each other, by simply posting the fuel they had left when they finished the mission.

I hope this helped,


EDIT----
Correct .zip attached on post #1 of this thread.

 

[T1234]

Thanks for that:thumbup: dous the proper expert settings disable the decent hold,that would make landing very hard on Miranda,is the manual hover control sensative enough? Its now a challenge that I cannot do :rofl:
Can a airobrake be done on Uranus to lose energy bringing APA down or is that pointless?

 

[dgatsoulis]

dous the proper expert settings disable the decent hold...?

No, the descend AP works just fine. But the manual controls are "sensitive enough" for a manual landing. That's how I land all the time.

Its now a challenge that I cannot do :rofl:

Optimal dV for this mission is ~1.7 km/s. With corrections it shouldn't be more than 1.9 km/s. The Ravenstar on the Ariel Prelude base has 4.2 km/s of dV in her tanks. It should be quite easy to complete the challenge.

Can a airobrake be done on Uranus to lose energy bringing APA down or is that pointless?

Too expensive (dV-wise). The optimal transfer trajectory is a Hohmann one.
Find a transfer trajectory that has Ariel as its apoapsis and Miranda as the periapsis.

 

[T1234]

Ive done it with 43.7% main and 58%rcs remaining,using decent hold and just transx.:woohoo:

 

[dgatsoulis]

Nicely done.:thumbup: That puts your dV usage at 2176 m/s.
To make it a bit more interesting, wait until at least another Orbinaut posts a score with the XR2 and then start a high-score board on post #1 of this thread.

 

[Castor]

I did it with 59.1% main fuel and 72% RCS remaining, using only TransX and attitude hold.

 

[T1234]

Nicely done.:thumbup: That puts your dV usage at 2176 m/s.
To make it a bit more interesting, wait until at least another Orbinaut posts a score with the XR2 and then start a high-score board on post #1 of this thread.

I don't know how:embarrassed:

 

[dgatsoulis]

I don't know how:embarrassed:

Copy the contents of the PHP code below and paste them at the end of post #1. Replace the "none" with the name of the player at the correct rank and replace the "0000.0" with the fuel they had left.

[CENTER][table][B][COLOR="Red"]Top [/COLOR][/B]|[B][COLOR="Red"]  [CENTER]XR2 Ravenstar[/CENTER] [/COLOR][/B]|[B][COLOR="Red"] Pilots[/COLOR][/B]
[CENTER][B]#[/B][/CENTER]|[CENTER][B]Name[/B][/CENTER]|[CENTER][B]Fuel left[/B][/CENTER]

[B]#1[/B]|[CENTER]none[/CENTER]|[CENTER]0000.0[/CENTER]

[B]#2[/B]|[CENTER]none[/CENTER]|[CENTER]0000.0[/CENTER]

[B]#3[/B]|[CENTER]none[/CENTER]|[CENTER]0000.0[/CENTER]

[B]#4[/B]|[CENTER]none[/CENTER]|[CENTER]0000.0[/CENTER]

[B]#5[/B]|[CENTER]none[/CENTER]|[CENTER]0000.0[/CENTER][/table][/CENTER]

To calculate the fuel: Fuel left = % Main * 6698 + % RCS * 804

For example:
Castor = 59.1% * 6698 + 72% * 804 = 4537.4 kg
T1234 = 43.7% * 6698 + 58% * 804 = 3393.3 kg

That puts Castor at rank #1 and you at #2.
As more Orbinauts try out the challenge and post their scores, update the table.

Also, attach the "correct" .zip file on post #1 and remove the incorrect ones from your posts (#1 and #5), as to avoid confusion with people trying the challenge with different settings. I'll remove the zip file from my post (#7), when you've done that.

 

[T1234]

I think I've done it right.