Question Crew Dragon demo-2 mission

[GodAtum]

So I can do this mission manually, but obviously that's not realistic and what happened in real life. How do I use some kind of autopilot to do all the things needed? The Falcon 9 mods comes with a great launch and circularisation AP, but stuck on the rest of how to automate the align, sync, approach and dock.

Tried UAP but I don't think I'm using it correctly as it completely goes off course.

 

[Joseph Borg]

So I can do this mission manually, but obviously that's not realistic and what happened in real life. How do I use some kind of autopilot to do all the things needed? The Falcon 9 mods comes with a great launch and circularisation AP, but stuck on the rest of how to automate the align, sync, approach and dock.

Tried UAP but I don't think I'm using it correctly as it completely goes off course.

I think., there was an already good mission pack/scenarios by @Brianj and Donamy
Called Crew Dragon Space X (see https://www.orbithangar.com/showAddon.php?id=933ad870-e430-476b-a2f3-f4cd907bf8e6 )

And the DM-1 crewed first scenario is what you're saying. However me too, after separation of 1st stage, and 2nd stage. I can't seem to efficiently align the dragon to the ISS.

Can anyone of the seniors point us to the right direction ?

 

[llarian]

BrianJ posted a new scenario just for the Saturday flight. I used it as the basis for scenario DM-2a. Worked pretty well.

Unless I've missed something, either of the DM scenarios take you automatically through launch up to Stage 2 ignition. From there you will have to manually pilot as per normal.

I tend to use both Rendezvous MFD and PursuitMFD to shepherd me through the rest of the flight.

You really don't need any MFD to help. Take a look at Tex's DG4 to ISS tutorial. It'll get you there. Just need a bit of practice.

Regards and have fun.

 

[BrianJ]

Hi,
yes I posted a scenario for the Saturday launch on the Crew Dragon add-on thread. As I mentioned previously, OCISLY is placed in the reported position which requires the 1st stage to fly on a 40deg azimuth, which is not aligned with ISS. I have a hunch this may be due to having to target the required abort zones. So, the upperstage needs to do some steering to align planes. I do this by opening the Falcon9 control panel after 1st stage separation, and setting inclination to 48deg, then when you get near the node with ISS orbit, set inclination to 51.65deg. I can get it down to about 0.1deg plane error at shutdown. I use AlignPlanesMFD for monitoring this.

What I don't know is whether SpaceX do it that way, or whether they simply use the first Dragon burn to correct plane error.

After that, I use RendezvousMFD to make the intercept, and now I have discovered PursuitMFD, I use that for docking

@llarian - I saw your comment re:camera shake - even the crew commented on the smoothness of the ride, so yes - too much shaking going on ;-)

Cheers,
Brian

 

[Donamy]

I believe the Dragon makes the plane change. I don't think they want a stuck 2nd stage in the same orbit with the ISS. I could be wrong.

 

[Joseph Borg]

Wow. Thanks BrianJ
Ill follow the guide you mentioned, and also @Ilarian.
The scn you posted, I need to copy paste the script into a .snc (text) file and use as per usual ? I Never done this before. I always download them as .scn files.

I wanted to thank you too for the amazing work you've done so far.

 

[GodAtum]

Hi,
yes I posted a scenario for the Saturday launch on the Crew Dragon add-on thread. As I mentioned previously, OCISLY is placed in the reported position which requires the 1st stage to fly on a 40deg azimuth, which is not aligned with ISS. I have a hunch this may be due to having to target the required abort zones. So, the upperstage needs to do some steering to align planes. I do this by opening the Falcon9 control panel after 1st stage separation, and setting inclination to 48deg, then when you get near the node with ISS orbit, set inclination to 51.65deg. I can get it down to about 0.1deg plane error at shutdown. I use AlignPlanesMFD for monitoring this.

What I don't know is whether SpaceX do it that way, or whether they simply use the first Dragon burn to correct plane error.

After that, I use RendezvousMFD to make the intercept, and now I have discovered PursuitMFD, I use that for docking

@llarian - I saw your comment re:camera shake - even the crew commented on the smoothness of the ride, so yes - too much shaking going on ;-)

Cheers,
Brian

Thanks, so using your scenario?

1. Set Inc to 40, ApA 400, PeA 200? launch at 19:22:45?
2. After 1st stage separation, set inclination to 48
3. When you get near the node with ISS orbit, set inclination to 51.65deg (how do I do this with the Falcon AP as it shuts down, or do you mean do it manually?)
4. RendezvousMFD says too far away, are you doing something in-between like sync orbit?

 

[BrianJ]

I believe the Dragon makes the plane change. I don't think they want a stuck 2nd stage in the same orbit with the ISS. I could be wrong.

That would make sense. I haven't tried including a plane change into the Dragon burn, I guess it won't cost too much dV.

Wow. Thanks BrianJ
Ill follow the guide you mentioned, and also @Ilarian.
The scn you posted, I need to copy paste the script into a .snc (text) file and use as per usual ? I Never done this before. I always download them as .scn files.

I wanted to thank you too for the amazing work you've done so far.

Thanks(on behalf of me and Donamy). Yes, just copy/paste into a .scn(text) file and put it in your scenarios folder.

Thanks, so using your scenario?

1. Set Inc to 40, ApA 400, PeA 200? launch at 19:22:45?
2. After 1st stage separation, set inclination to 48
3. When you get near the node with ISS orbit, set inclination to 51.65deg (how do I do this with the Falcon AP as it shuts down, do I need to go to orbit normal?)

AP should still be active at that point. "Near" is a loose term - check on AlignPlaneMFD when you're about 180s before node. But see Donamy's post above - might be more realistic to do the plane change with Dragon - I think I'd use IMFD DeltaV function for that, to get the right PeA raise and plane change in one burn.
Cheers,
Brian

 

[Donamy]

That would make sense. I haven't tried including a plane change into the Dragon burn, I guess it won't cost too much dV.

Thanks(on behalf of me and Donamy). Yes, just copy/paste into a .scn(text) file and put it in your scenarios folder.

AP should still be active at that point. "Near" is a loose term - check on AlignPlaneMFD when you're about 180s before node. But see Donamy's post above - might be more realistic to do the plane change with Dragon - I think I'd use IMFD DeltaV function for that, to get the right PeA raise and plane change in one burn.
Cheers,
Brian

I think they use the nose drakos.

 

[GodAtum]

That would make sense. I haven't tried including a plane change into the Dragon burn, I guess it won't cost too much dV.

Thanks(on behalf of me and Donamy). Yes, just copy/paste into a .scn(text) file and put it in your scenarios folder.

AP should still be active at that point. "Near" is a loose term - check on AlignPlaneMFD when you're about 180s before node. But see Donamy's post above - might be more realistic to do the plane change with Dragon - I think I'd use IMFD DeltaV function for that, to get the right PeA raise and plane change in one burn.
Cheers,
Brian

Thanks but in your scenario the 1st stage ends after the node, then the AP completes before it reaches the next node. What launch time are you using? What PeA and ApA are you using? RendezvousMFD says too far away, are you doing something in-between like sync orbit?

 

[BrianJ]

Thanks but in your scenario the 1st stage ends after the node, then the AP completes before it reaches the next node. What launch time are you using? What PeA and ApA are you using? RendezvousMFD says too far away, are you doing something in-between like sync orbit?

I'm using the scenario I posted for Saturday's launch, liftoff at 19:22:45 UTC. Here's a pic of my AlignPlanesMFD at 1st stage MECO, still approaching Descending Node with ISS orbit. At this point I change the inclination to 48deg, wait until 180s before node, change inclination to 51.65.

After Dragon sep., I do a burn at Apogee to raise PeA to ~300km, and then a little burn to align planes better.
Then wait for 5 or 6 orbits to catch up with ISS and activate RendezvousMFD. I usually do burns on RendezvousMFD midway between Perigee and Apogee.
Hope that helps

Brian

 

[GodAtum]

I'm using the scenario I posted for Saturday's launch, liftoff at 19:22:45 UTC. Here's a pic of my AlignPlanesMFD at 1st stage MECO, still approaching Descending Node with ISS orbit. At this point I change the inclination to 48deg, wait until 180s before node, change inclination to 51.65.
View attachment 17131
After Dragon sep., I do a burn at Apogee to raise PeA to ~300km, and then a little burn to align planes better.
Then wait for 5 or 6 orbits to catch up with ISS and activate RendezvousMFD. I usually do burns on RendezvousMFD midway between Perigee and Apogee.
Hope that helps

Brian

Interesting, not getting that plane at all
https://imgur.com/1EBcfRN

 

[BrianJ]

Interesting, not getting that plane at all

I think you set the Target Inclination for the Falcon9 to 40deg before launch? Leave it at 54deg until MECO, then set to 48deg, etc.

 

[llarian]

Wow. Thanks BrianJ
Ill follow the guide you mentioned, and also @Ilarian.
The scn you posted, I need to copy paste the script into a .snc (text) file and use as per usual ? I Never done this before. I always download them as .scn files.

I wanted to thank you too for the amazing work you've done so far.

I use Crimson Editor as my editor of choice because I have great freedom to change the file extension to anything I want without Windows firing a bunch of messages at me. I just copied the scenario that BrianJ posted and pasted into a new file, saved as whatever I wanted to call it in the directory I wanted it to go to (Scenarios/Crew Dragon) and away I went.

 

[GodAtum]

I think you set the Target Inclination for the Falcon9 to 40deg before launch? Leave it at 54deg until MECO, then set to 48deg, etc.

Hi,
yes I posted a scenario for the Saturday launch on the Crew Dragon add-on thread. As I mentioned previously, OCISLY is placed in the reported position which requires the 1st stage to fly on a 40deg azimuth, which is not aligned with ISS. I have a hunch this may be due to having to target the required abort zones. So, the upperstage needs to do some steering to align planes. I do this by opening the Falcon9 control panel after 1st stage separation, and setting inclination to 48deg, then when you get near the node with ISS orbit, set inclination to 51.65deg. I can get it down to about 0.1deg plane error at shutdown. I use AlignPlanesMFD for monitoring this.

What I don't know is whether SpaceX do it that way, or whether they simply use the first Dragon burn to correct plane error.

After that, I use RendezvousMFD to make the intercept, and now I have discovered PursuitMFD, I use that for docking

@llarian - I saw your comment re:camera shake - even the crew commented on the smoothness of the ride, so yes - too much shaking going on ;-)

Cheers,
Brian

Ah sorry I'm getting mixed up ... on your 1st post you say "the 1st stage to fly on a 40deg azimuth"

 

[BrianJ]

Ah sorry I'm getting mixed up ... on your 1st post you say "the 1st stage to fly on a 40deg azimuth"

Yes, launch azimuth is different to orbit inclination
Just in case it's not clear, this might help......
https://www.orbiterwiki.org/wiki/Launch_Azimuth

 

[Ezra]

Hi, . . . even the crew commented on the smoothness of the ride, so yes - too much shaking going on ;-)

Cheers,
Brian

Maybe you missed what the crew member actually said. He said the first stage was smooth. The second stage was "huffing and puffing." The space shuttle second stage was a "smoother" ride.