OHM Launch and Rendezvous Autopilot for Greg Burch's LSTS in Lua

[OrbitHangar]

Author: indy91

This is a launch and rendezvous autopilot for Greg Burch's Medium Utility Lander (LSTS2204) and Heavy Utility Lander (LSTS2312). The Scenario is a launch into a lunar orbit and Rendezvous with the Gilgamesh transporter (LSTS2012). It is based on the Apollo 11 Lunar Ascent Profile.
The features of the script are:
 
-Calculation of the launch time
-Powered Ascent with crossrange capability
-Coelliptic Sequence Initiation (CSI): Raising the Perilune to 45 NM
-Planar Correction (if necessary)
-Constant Delta Height (CDH): Adjustment of the orbit to be coelliptic with the target
-Terminal Phase Initiation (TPI): Burn along the Line-of-Sight to initiate a rendezvous course
-performing two Mid Course Corrections (MCC1 and MCC2)
-The Lander should be now on a collision course to the transporter

Read the manual for all required addons.

Updates:  -4. Jan. 2013: -Ascent autopilot based on Apollo guidance equations
                                            -All maneuvers improved and more realistic
                                            -PDF manual added 

                  -8. Nov. 2012: -Minor bug fixes and improvements

                  -6. Nov. 2012: -Now working for the Heavy Lander
                                            -Added Braking
                                            -Holding Line-of-Sight while MCC and Braking

 


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[Interceptor]

Hello,the 'autopilot()'. command won't work.
execution error

 

[indy91]

Perhaps my description was misleading. You don't have to put the ' ' before and after the autopilot() to start the function. If you didn't do that I have no idea and will look tomorrow at it.

 

[Interceptor]

Thanks,indy91 I'll give it another try.

---------- Post added at 10:10 PM ---------- Previous post was at 04:32 PM ----------

Works Great,Nice job.Thanks:tiphat:

 

[indy91]

Good to hear that it works for you. Now I can continue to work on it.

 

[Interceptor]

Hello indy91,Houston we have a problem with the new heavy lander scenario,the LSTS2312 gets to orbit nicely,but once it reaches CSI,it deorbits itself,and eventualy crashes in to the Moon.

---------- Post added 11-08-12 at 04:33 AM ---------- Previous post was 11-07-12 at 06:32 AM ----------

Hi again indy91,ok I also tested your newest AP on the LSTS2204 medium lander,and I am getting an MCC1 Execution error.

---------- Post added at 06:46 PM ---------- Previous post was at 04:33 AM ----------

HI,indy91,still the same with the newest version of the AP version3,still at CSI, the Heavy lander deorbiting,and crashing in to the ground,I have not tried out the medium lander yet,will shortly thou.

---------- Post added at 07:30 PM ---------- Previous post was at 06:46 PM ----------

OK,I tested the medium lander scenario with the AP version3,and everything works great,but you might want to take a look at the CSI stage,it seems to act kind of weird,compared to your first version of the AP.Thanks

 

[indy91]

Hmm, the CSI works just fine for me. The lander is waiting until 60 seconds before the apoapsis. Then the prograde autopilot is started and the lander waits until the right time to burn. The burn will raise the periapsis to about 82 km.
In which part does the autopilot not work for you?

 

[Interceptor]

Hi,andy91, if its the heavy lander it still has the same problem crashing into the ground after,CSI,so when the LSTS2312 starts it's burn for the CSI it never stops burning, and if it's the medium lander, I think its' ok ,I tried it a second time.and all seems good with it now,I think I meant by acting weird is that after the burn at CSI,the LSTS2204,seems to jump back before the apolune,but I am no expert.

 

[indy91]

It is perfectly normal, that the apolune changes during the CSI. The problem with the heavy lander during the CSI probably comes from an inaccurate insertion. I never experienced it, but the next version won't do infinite burns anymore.

 

[indy91]

Major update. Everything is reworked and the new features are:
-The launch time is now based on actual calculations instead of good guesses
-A new ascent autopilot, which is almost the actual Apollo Lunar Module ascent guidance. It is capable to do the insertion with 0° relative inclination.
-All maneuvers are more or less based on Apollo guidance equations. This makes the ascent and rendezvous more realistic, but also a little bit less precise.
-I removed the braking in the autopilot, because this was done manually by the astronauts

 

[Interceptor]

Hi indy91,I have finally had a chance to test out your new ascent autopilot5,and I have found a bug with the heavy lander lsts-2312,after CHD burn,the lander just continues to get father,and farther away in distance from the lsts-2012 Gilgamesh Transporter. I have used it twice now,and ran into the same problem,I have not tried out the medium lander-lsts2204 yet,but will do soon.Thanks

 

[indy91]

Did you use the scenario, that comes with the autopilot? If not, can you post a scenario file shortly before the CDH-burn? That would make it easier for me to find the problem. And what was roughly the dv for the CDH-burn?

 

[Interceptor]

Hi indy91,yes I used the included scenario.

 

[indy91]

Hmm, then please post a scenario file anyway. So I can see, if the previous burns worked ok and your orbit is right. Before or after CDH doesn't matter.

 

[Interceptor]

OK,sorry indy91,no problems this time,flew,and docked perfectly,I tried it in a clean installation of orbiter2010P1,it must have been another addon that was effecting the autopilot"s performance,all"s well that ends well.Thanks