Problem IMFD orbit insert major flaw

[markl316]

I was approaching a planet, and i executed the orbit insert program in IMFD 5.1. I found 2 major problems:
1. It did not put me at the desired altitude indicated by the base approach program.
2. My orbit was not circular (even a negative PeA).

I used ONE MFD for all of this (no sharing). What am i doing wrong? It was working fine the other day, its being inconsistent.

 

[Dr Pepper]

Hmm, not so sure that this is an actual flaw as opposed to simple human error. IMFD is very accurate when used properly, which can be hard sometimes, so do you mind posting what exactly you did to set up the orbit insert program?

Even one small, accidentally skipped step can cause huge errors (I once ended up flying straight into a planet because I forgot to set prograde instead of retrograde on the slingshot program).

 

[markl316]

Sure.

BEGIN_DESC
Orbiter saved state at T = 432937089
END_DESC
BEGIN_ENVIRONMENT
  System Sol
  Date MJD 66636.7222714953
END_ENVIRONMENT
BEGIN_FOCUS
  Ship XR2-01
END_FOCUS
BEGIN_CAMERA
  TARGET XR2-01
  MODE Cockpit
  FOV 40.00
END_CAMERA
BEGIN_HUD
  TYPE Surface
END_HUD
BEGIN_MFD Left
END_MFD
BEGIN_MFD Right
END_MFD
BEGIN_PANEL
END_PANEL
 
BEGIN_SHIPS
ISS:ProjectAlpha_ISS
  STATUS Orbiting Sun
  RPOS -80285800275.72 4414576248.30 -71345230774.96
  RVEL 11097.446 9782.213 -26364.260
  AROT -130.78 -26.17 -128.09
  VROT -0.04 -0.06 0.14
  PRPLEVEL 0:1.000
  IDS 0:588 100 1:586 100 2:584 100 3:582 100 4:580 100
  NAVFREQ 0 0
  XPDR 466
END
Mir
  STATUS Orbiting Sun
  RPOS 93322025208.34 182706113.55 73447428011.10
  RVEL -16305.544 1785.021 32089.028
  AROT -136.61 14.16 143.17
  VROT 0.03 -0.08 -0.02
  IDS 0:540 100 1:542 100 2:544 100
  XPDR 482
END
Luna-OB1:Wheel
  STATUS Orbiting Sun
  RPOS -145649819591.47 -279430744.60 96125337076.19
  RVEL -14337.500 390.417 -22384.847
  AROT -45.96 38.51 -74.85
  VROT 0.06 -0.06 10.00
  IDS 0:560 100 1:564 100
  XPDR 494
END
XR2-01:XR2Ravenstar
  STATUS Orbiting Pluto
  RPOS -5072408.23 2171779.80 16201688.91
  RVEL 3926.417 -1872.499 -10380.239
  AROT -172.19 -9.47 -10.36
  PRPLEVEL 0:0.740 1:0.996 3:1.000
  IDS 0:199 100
  NAVFREQ 588 466 84 114
  XPDR 193
  SECONDARY_HUD 3
  LAST_ACTIVE_SECONDARY_HUD 0
  ADCTRL_MODE 0
  TAKEOFF_LANDING_CALLOUTS 11254.289251 195.619000 195.627000 0.000000 -11227.299159
  APU_FUEL_QTY 0.945
  LOX_QTY 0.539673
  CABIN_O2_LEVEL 0.209
  CREW_STATE 0
  INTERNAL_SYSTEMS_FAILURE 0
  COGSHIFT_MODES 0 0 0
  MWS_ACTIVE 0
  COOLANT_TEMP 31.200
  DMG_0 1.000000 Left Wing
  DMG_1 1.000000 Right Wing
  DMG_2 1.000000 Left Aileron
  DMG_3 1.000000 Right Aileron
  DMG_4 1.000000 Landing Gear
  DMG_5 1.000000 Nosecone
  DMG_6 1.000000 Retro Doors
  DMG_7 1.000000 Top Hatch
  DMG_8 1.000000 Radiator
  DMG_9 1.000000 Airbrake
  DMG_10 1.000000 Left Main Engine
  DMG_11 1.000000 Right Main Engine
  DMG_12 1.000000 Left SCRAM Engine
  DMG_13 1.000000 Right SCRAM Engine
  DMG_14 1.000000 Fore Hover Engine
  DMG_15 1.000000 Aft Hover Engine
  DMG_16 1.000000 Left Retro Engine
  DMG_17 1.000000 Right Retro Engine
  DMG_18 1.000000 Forward Lower RCS
  DMG_19 1.000000 Aft Upper RCS
  DMG_20 1.000000 Forward Upper RCS
  DMG_21 1.000000 Aft Lower RCS
  DMG_22 1.000000 Forward Star. RCS
  DMG_23 1.000000 Aft Port RCS
  DMG_24 1.000000 Forward Port RCS
  DMG_25 1.000000 Aft Star. RCS
  DMG_26 1.000000 Outboard Upper Port RCS
  DMG_27 1.000000 Outboard Lower Star. RCS
  DMG_28 1.000000 Outboard Upper Star. RCS
  DMG_29 1.000000 Outboard Lower Port RCS
  DMG_30 1.000000 Aft RCS
  DMG_31 1.000000 Forward RCS
  DMG_32 1.000000 Bay Doors
  IS_CRASHED 0
  MET_STARTING_MJD 60739.454851
  INTERVAL1_ELAPSED_TIME -1.000000
  INTERVAL2_ELAPSED_TIME -1.000000
  MET_RUNNING 1
  INTERVAL1_RUNNING 0
  INTERVAL2_RUNNING 0
  ACTIVE_MDM 3
  TEMP_SCALE 2
  CUSTOM_AUTOPILOT_MODE 0
  AIRSPEED_HOLD_ENGAGED 0
  SCRAM0DIR 0.000000 0.000000 1.000000
  SCRAM1DIR 0.000000 0.000000 1.000000
  HOVER_BALANCE 0.000
  MAIN0DIR 0.000000 0.000000 1.000000
  MAIN1DIR 0.000000 0.000000 1.000000
  GIMBAL_BUTTON_STATES 0 0 0 0 0 0
  ATTITUDE_HOLD_DATA -1.000000 0.000000 0 0 0.000000
  DESCENT_HOLD_DATA 0.000000 -3.000000 0
  AIRSPEED_HOLD_DATA 0.000000
  OVERRIDE_INTERLOCKS 0 0
  TERTIARY_HUD_ON 1
  CREW_DISPLAY_INDEX 0
  GEAR 0 0.0000
  RCOVER 0 0.0000
  NOSECONE 0 0.0000
  AIRLOCK 0 0.0000
  IAIRLOCK 0 0.0000
  CHAMBER 0 0.0000
  AIRBRAKE 0 0.0000
  RADIATOR 1 1.0000
  HATCH 0 0.0000
  SCRAM_DOORS 0 0.0000
  HOVER_DOORS 0 0.0000
  BAY_DOORS 0 0.0000
  APU_STATUS 0
  EXTCOOLING_STATUS 0
  TRIM 0.018
  LIGHTS 0 0 0
  XRUMMU_CREW_DATA_VALID 1
  UMMUCREW XI0-Mark_Lieberbaum-17-65-78
  UMMUCREW XI1-Kara_Miller-32-65-58
  PAYLOAD_SCREENS_DATA 0.2 0 1 1
END
SH-03:ShuttleA
  STATUS Landed Earth
  BASE Habana:4
  POS -82.3982414 23.0005396
  HEADING 70.00
  PRPLEVEL 0:1.000 1:1.000
  NAVFREQ 0 0
  XPDR 0
  PODANGLE 0.0000 0.0000
  DOCKSTATE 0 0.0000
  AIRLOCK 0 0.0000
  GEAR 0 0.0000
  PAYLOAD MASS 0.0 0
END
PB-01:ShuttlePB
  STATUS Landed Earth
  BASE Habana:1
  POS -82.4000000 22.9994604
  HEADING 22.00
  PRPLEVEL 0:1.000
  NAVFREQ 0 0
END
GL-02:DeltaGlider
  STATUS Landed Mars
  BASE Olympus:3
  POS -135.4300001 12.7366196
  HEADING 0.00
  PRPLEVEL 0:1.000 1:1.000 2:1.000
  NAVFREQ 0 0 0 0
  XPDR 0
  GEAR 1 1.0000
END
SH-01:ShuttleA
  STATUS Landed Moon
  BASE Brighton Beach:1
  POS -33.4375000 41.1184068
  HEADING 0.00
  PRPLEVEL 0:1.000 1:1.000
  NAVFREQ 0 0
  XPDR 0
  PODANGLE 0.0000 0.0000
  DOCKSTATE 0 0.0000
  AIRLOCK 0 0.0000
  GEAR 0 0.0000
  PAYLOAD MASS 0.0 0
END
Pluto43:DGIVPreludeII
  STATUS Landed Pluto
  POS 110.9962670 2.4561400
  HEADING 90.00
  NAVFREQ 0 0
  XPDR 320
  SKINNAME Pluto43
  DISPLAYLANDINGPAD 2   ;0=ground base 1=mountain base (eg: phobos) 2= disable
  MAINAIRLOCK 0 0.0000
  PADLIGHT1MODE 0
  PADLIGHT1STATE 0
  UMMUCREW Sec-Vernon_Ready-44-67-81
  UMMUCREW Sec-Stephen_Pye-25-70-87
  UMMUCREW -Rolf_Feller-35-73-90
  UMMUCREW -Mika_Huovinen-22-67-60
  UMMUCREW -Gregory_Butzek-29-68-72
  UMMUCREW APhy-Scott_Kingsley-33-60-90
  UMMUCREW -John_Stolarz-44-61-63
  UMMUCREW APhy-Kenji_Sakaba-41-63-81
  UMMUCREW -Jeremy_Demonte-47-69-66
  UMMUCREW Tech-Antonio_Henriquez-41-71-92
  UMMUCREW Sec-Ivan_Bartulovic-38-66-65
  UMMUCREW -Palmas_Timothee-33-63-63
  UMMUCREW Tech-Sonny_Jakobsen-48-74-72
  UMMUCREW Sci-Sonny_Jakobsen-35-71-77
  UMMUCREW -Jean_Marc_Daigre-24-73-78
  UMMUCREW Eng-Ezekiel_Sutton-46-64-87
  UMMUCREW -Justin_Boubong-35-68-82
  UMMUCREW Sec-Adrian_Crownover-35-71-71
  UMMUCREW Doc-Thomas_Rammacher-52-69-83
  UMMUCREW Capt-Guy_Holtz-49-63-61
END
Charon67:DGIVPreludeII
  STATUS Landed Charon
  POS -72.0384870 2.4557100
  HEADING 90.00
  NAVFREQ 0 0
  XPDR 320
  SKINNAME Charon67
  DISPLAYLANDINGPAD 2   ;0=ground base 1=mountain base (eg: phobos) 2= disable
  MAINAIRLOCK 0 0.0000
  PADLIGHT1MODE 0
  PADLIGHT1STATE 0
  UMMUCREW Eng-Vernon_Ready-29-62-88
  UMMUCREW Sec-Giorgio_Borgo-32-70-68
  UMMUCREW -Philip_Hyman-26-69-62
  UMMUCREW -Stephen_Pye-36-68-85
  UMMUCREW -Joel_Delwasse-33-72-78
  UMMUCREW Doc-Nicola_Rinaldi-39-60-63
  UMMUCREW Chem-Scott_Kingsley-47-69-71
  UMMUCREW Sec-Kenji_Sakaba-38-66-68
  UMMUCREW Sec-Elmar_Schulz-58-69-69
  UMMUCREW Sec-Sonny_Jakobsen-25-62-81
  UMMUCREW -Ludwig_Verschuren-43-71-66
  UMMUCREW -Michael_Collis-24-67-60
  UMMUCREW Tech-Juergen_Vollmer-51-73-83
  UMMUCREW Sci-Torstein_Sonstabo-20-68-87
  UMMUCREW Sec-Caudron_Vincent-26-69-60
  UMMUCREW Sec-Jose_Aldonio_Melim-54-70-82
  UMMUCREW -Chris_Willis-47-61-89
  UMMUCREW Capt-Don_Blakesford-49-63-61
  UMMUCREW Capt-Ian_Uriela-49-63-61
END
XR2-01_Bay:XRPayloadBay
  STATUS Orbiting Sun
  RPOS 4817346346416.48 -1030796192612.85 -3218897873725.16
  RVEL 7217.047 -3154.229 -7200.709
  AROT -172.19 -9.47 -10.36
  ATTACHED 0:3,XR2-01
END
END_SHIPS
BEGIN_ExtMFD
END

Requires DGIV, XR2 Ravenstar, and some Pluto addon.

Here's what I did:
I opened IMFD v. 5.1 on the left
I hit MNU, and selected Baseapproach
I set my target to PreludeII Pluto (an addon I made. you might not have it. The coordinates are 111 deg east, 2.4 deg north).
I set the altitude to 40 km.
I performed AB.
I got into the Orbit Insert course program.
I hit AB.
At the end, I was in a 45x8 km orbit.

 

[Tommy]

Does that Prelude Base have an actual base, or is it just the Prelude vessel placed on Pluto?

 

[markl316]

For me, its an actual base. I made an addon on Dan's site with 12 total prelude bases on the major moons of the outer planets. Oh and by the way, on Base Approach, Ref=Pluto, Tgt=PreludeII Pluto, Src=XR2-01. And on orbit insert: Ref=Pluto, Tgt=Ecliptic, Src=XR2-01

The link for my addon: http://orbiter.dansteph.com/index.php?disp=dgIVMore&cat=All&sort=&page=2&search=&searchtype= Numbers 97-99 (sorry for no pics)

 

[Tommy]

K, will try to do a little more testing tomorrow, I've noticed that Orbit Insert doesn't always work the way I expect it to either. Didn't think much of it because I usually do my insert burns manually, but I'll look into it.

 

[markl316]

Thanks Tommy. If it helps, I have all 3 IMFD's installed (4.2.1, 4.6, and 5.1). 4.2.1 and 5.1 don't work, and 4.6 puts me in a circular orbit, but not at the desired altitude.

 

[jarmonik]

This is not actually a flaw. The Orbit Insert program can not change the orbit insertion altitude because it can't change the position of the vessel in the space. Therefore, it can only effect to the altitude of the far side of the orbit. (opposite to location of the orbit insertion burn).

You need to ensure the correct orbit insertion altitude before the orbit insertion burn by using Planet Approach or Base Approach programs.

This, usually, requires two burns. One after entering into the SOI of the planet and an other correction burn much closer to the planet. After that you are ready to go for Orbit Insert.

 

[Tommy]

I suspected it was something like that. I always use the Map program at max accuracy to fine tune my approach after using the Base Approach autoburn.

 

[markl316]

But my concern is that Orbit Insert is not putting me into a circular orbit, and also during the autoburn the altitude (displayed on the orbit insert program) actually rises during the burn. I'll post a playback of this in the next day or so.

 

[Tommy]

If the Pe on your current course is below the specified orbit altitude when you engage AB in Orbit Insert, then IMFD cant circularize. It seems to try giving you an eccentric orbit with an "average" altitude of whatever was specified. Never assume the Pe will be what you specified in Planet Approach, always check it Map prgogram (at max accuracy) and adjust if needed. I've also had trouble if I hit the AB when I was still quite a ways from the target planet. I'd try waiting until PeT is less than 1k sec.

 

[markl316]

Still not working.
On the orbit insert program (IMFD 5.1) you can't even adjust eccentricity or PeD. How do you adjust that? When I hit NXT or PRV nothing happens.
Tommy, could you try to use the scenario I provided at the beginning of this thread and see if you can get this to work with IMFD v. 5.1? That would be great.

 

[jarmonik]

Still not working.
On the orbit insert program (IMFD 5.1) you can't even adjust eccentricity or PeD. How do you adjust that? When I hit NXT or PRV nothing happens.
Tommy, could you try to use the scenario I provided at the beginning of this thread and see if you can get this to work with IMFD v. 5.1? That would be great.

Are you sure that the version, you are using, is the latest (5.1m). In that version you can define the shape of the orbit by using one of following parameters:
-Eccentricity
-Semi-major axis
-Apopais altitude
-Orbit period

Also don't forget that altitude of the vessel will decrease during the burn. That's the reason why the Orbit Insert program is showing lower PeA and ApA values than Planet Approach or Base Approach programs. For an example during typical Mars orbit insertion altitude can decrease as much as 40km. That depends from burn time and planet gravity.

 

[markl316]

Ok, thanks, I thought Orbit Insert was supposed to keep u at the same PeD as base approach. And about the uncircular orbit, this was when I was doing a Pluto encounter (speed 11.5 km/s, circular orbit speed 0.9 km/s). So i just manually got the eccentricity down from 150 to like 10, and it worked much better. I guess it loses a bit of accuracy getting the ecc from a ridiculously high number (150) down to 0. Works now Thanks for all your support.