Phoenix Mission Upgrade

BrianJ

Addon Developer
Addon Developer
Joined
Apr 19, 2008
Messages
1,385
Reaction score
359
Points
98
Location
Code 347
Now I've got the correct masses for the various spacecraft components (finally!) I've reworked the .dll's for a more accurate EDL profile (and a "dust-off" effect on landing :) You can grab 'em here:
http://myweb.tiscali.co.uk/briansutilitysite/phoenix_upgrade_220508.zip
also includes a Mars approach .scn starting at 20:00 UTC on Sunday evening. (You will need the "Phoenix v.3" from Avsim installed as well)

I'll be running the sim in real time on Sunday, and just for fun I'm going to stream it live via Ustream, here:
http://www.ustream.tv/channel/obc

Good luck Phoenix!

Regards,
Brian

EDIT: I found that I needed to change the SidRotOffset parameter in the Mars.cfg to
SidRotOffset = -0.812 otherwise the landing is quite a way off the nominal landing site. I'm pretty sure the EDL profile is quite accurate, so I'm not entirely sure why that is.
 

BrianJ

Addon Developer
Addon Developer
Joined
Apr 19, 2008
Messages
1,385
Reaction score
359
Points
98
Location
Code 347
You're welcome, Doug :)

I've just been trying to nail down the SidRotOffset parameter using the figures for sunrise and sunset on Mars at various locations given by this site www.marsbase.net (the same method that Chode used?) and I reckon
-0.79 is pretty good.

But Chode is usually right on the money with ephemeris parameters...so take your pick!
 

Chode

Addon Developer
Addon Developer
Beta Tester
Joined
Mar 21, 2008
Messages
108
Reaction score
1
Points
0
The correct value for SidRotOffset is -0.7719243, from the IAU (International Astronomical Union) and USGS. This value will be included in the next Orbiter version.

If you're landing is still off, it may be that your aerodynamics are a little off, or the atmospheric model in Orbiter isn't precise enough.

Regards
 

Zeehond

New member
Joined
Mar 20, 2008
Messages
64
Reaction score
0
Points
0
With the value from Chode and using cfgdata.exe (-84=phoenix, 499=mars, 23:00 UT), landing occurs maybe 1 second early, so that is very precise. :)

The location of the landing is: 129.981 W (= 230.019 E) and 68.579 N with those values. From the latest information (see http://planetary.org/blog/) the landing site should be 223.4 E and 68.25 N.

Brian, your timing is very precise, but the profile needs more tweaking, I am afraid. You need to have less drag somewhere in the EDL.
 

Xantcha

Addon Developer
Addon Developer
Joined
Mar 26, 2008
Messages
203
Reaction score
0
Points
0
Simulation: 230,811E 68,591N - about 170 km from planned landing position. Not that precise, but interesting result anyway.

And live video was really fun (I started watching from reentry part), thanks BrianJ.

Now waiting for information on real Phoenix. Fingers crossed for perfect landing
 

Scarecrow

New member
Joined
Feb 10, 2008
Messages
277
Reaction score
1
Points
0
Location
USA
Hooray for a perfect landing! 1/4 degree off level is really flat!:speakcool: Hopefully all the ground based stuff goes all right too.


They probably won't read this, but congrats JPL:cheers:!

edit: oops, wrong thread...
 

BrianJ

Addon Developer
Addon Developer
Joined
Apr 19, 2008
Messages
1,385
Reaction score
359
Points
98
Location
Code 347
Yep, perfect landing by Phoenix :) Congrats to the mission team!
I'm sure we'll be getting some really interesting science results in due course.
The correct value for SidRotOffset is -0.7719243, from the IAU (International Astronomical Union) and USGS. This value will be included in the next Orbiter version.

If you're landing is still off, it may be that your aerodynamics are a little off, or the atmospheric model in Orbiter isn't precise enough.

Thanks Chode, I'll try that offset and see how close I get :-D Both factors you mention are probable - together with the fact that the JPL Horizons
vectors are from a pre-launch spice file, and the target site was changed a couple of times since then.

Hope my "live" vid streaming experiment was fun for those that saw it - and it was nice to have a chat while watching Mars getting bigger in the window! Cheers guys.

All the best,
Brian
 

Whatu

Interplanetary Stowaway
Joined
Apr 21, 2008
Messages
202
Reaction score
0
Points
16
Location
Tenerife
Hope my "live" vid streaming experiment was fun for those that saw it - and it was nice to have a chat while watching Mars getting bigger in the window! Cheers guys.

Yeah sure it was fun! It was nice to be able to "see" what was really happening in real-time, though we would still see the thing with 15 minutes delay if we looked at it trough a giant telescope...

damn, why cant time be universal?

Thanks for the streaming :lol:;)
 

Chode

Addon Developer
Addon Developer
Beta Tester
Joined
Mar 21, 2008
Messages
108
Reaction score
1
Points
0
Simulation: 230,811E 68,591N - about 170 km from planned landing position. Not that precise, but interesting result anyway.

Predicting the trajectory for an aerobraking entry seems to be a bit tricky.

The actual landing spot of Phoenix looks to be about 60 km from the planned landing site (but still just within the 99.9 percent "ellipse"), so JPL also had a substantial error in their predictions.

Regards
 

Matte

New member
Joined
Nov 24, 2007
Messages
169
Reaction score
0
Points
0
Location
Milano
hi Brian, i'm absolutely enjoing your add-ons.
i have a question. can i install the new V4 of Phoenix over a previous V3 version? will the files overwrite completely without problems?
thanks
Matte
 

BrianJ

Addon Developer
Addon Developer
Joined
Apr 19, 2008
Messages
1,385
Reaction score
359
Points
98
Location
Code 347
can i install the new V4 of Phoenix over a previous V3 version? will the files overwrite completely without problems?
Hi Matte,
Yes - there shouldn't be any problem.

Cheers,
Brian
 

C3PO

Addon Developer
Addon Developer
Donator
Joined
Feb 11, 2008
Messages
2,598
Reaction score
8
Points
53
The Phoenix addon has been removed from Avsim. Any ideas why?

[edit] It looks like ALL Orbiter files have been removed. :mad::censored:
 

Artlav

Aperiodic traveller
Addon Developer
Beta Tester
Joined
Jan 7, 2008
Messages
5,612
Reaction score
144
Points
153
Location
Moscow
Website
orbides.org
The Phoenix addon has been removed from Avsim. Any ideas why?

[edit] It looks like ALL Orbiter files have been removed. :mad::censored:

Are you sure you are checking the right Avsim?
They are all up for me, "Phoenix Mission v.4 Brian Jones 2182k 212 04-Jun-2008" included.

[edit] Tried to download... File not found for all. Other categories working.
 

BrianJ

Addon Developer
Addon Developer
Joined
Apr 19, 2008
Messages
1,385
Reaction score
359
Points
98
Location
Code 347
Avsim are upgrading their servers, which "may take a few days" apparently. Should be back to normal soon :)
 

Rosey

New member
Joined
Mar 26, 2008
Messages
79
Reaction score
0
Points
0
The Phoenix addon is great .. not too complicated and very educational .. I sowed my granddaughter about it using the addon and she was thilled
 
Top