Re-entry

[Jason210]

I have problems with re-rentry. I follow the instructions ( that we published in DGII manual), reduce the Peri to about
6400, and then do the PRO104SPEC40.  I as I come into contact with the air, I seem to bounce off it again like a
stone skimming a pond. This bounce happens several times, and then I come in too steep. Often I have to use the
hover burners to flatten out this cycle.

And how do you get to a specific place, like Cape Canaveral? I either come too far before it, or too far after, usually to
the tune of around 1000km. That's too much flying and I run out of fuel, half the time end up in the drink.

[StarLost]

Somewhere in here you will find a series on re-entry by MichelleMegan. Start there.

A good tool to practice with, in the planning stage of reentry, is jarmonik's BaseSyncMFD. Take a look for it at
http://koti.mbnet.fi/jarmonik/Orbiter.html

[MinusSeven]

I always make sure the apoapsis is low as well, usually no more than 250 kms. I believe the space shuttle always lowers their
orbit before they do their final de-orbit burn.

If you have a high apoapsis of for example 10,000 kms, the velocity is going to be higher at periapsis than if you had an
apoapsis of 200 kms.

[Jason210]

Thanks for the help.

[markl316]

Jason210 wrote:
I have problems with re-rentry. I follow the instructions ( that we published in DGII manual), reduce the Peri to about
6400, and then do the PRO104SPEC40.  I as I come into contact with the air, I seem to bounce off it again like a
stone skimming a pond. This bounce happens several times, and then I come in too steep. Often I have to use the
hover burners to flatten out this cycle.

And how do you get to a specific place, like Cape Canaveral? I either come too far before it, or too far after, usually to
the tune of around 1000km. That's too much flying and I run out of fuel, half the time end up in the drink.

I have actually created a playback for orbiter 2006 that demonstrates a complete dgIII reentry, starting docked with
the ISS, all the way to touchdown. It is available at http://orbithangar.com/searchid.php?ID=2453. I really landed
with gear, but it doesn't show up in the playback.

[Tragamin]

markl....i tried to watch that playback but it just showed the ISS, the lunar space station and the DGIII "stuck" to the
sun...maybe something to do with orbiter 060504 ?

[markl316]

I get that a lot.   I don't know what's wrong.  Here's a copy of the scenario file.

BEGIN_DESC
DGIII reentry from ISS to Cape Canaveral.
END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 60247.6066656135
END_ENVIRONMENT

BEGIN_FOCUS
  Ship GL-01
END_FOCUS

BEGIN_CAMERA
  TARGET GL-01
  MODE Cockpit
  FOV 50.00
END_CAMERA

BEGIN_HUD
  TYPE Orbit
  REF AUTO
END_HUD

BEGIN_MFD Left
  TYPE Orbit
  PROJ Ship
  FRAME Ecliptic
  ALT
  REF Earth
END_MFD

BEGIN_MFD Right
  TYPE Map
  REF Earth
  BTARGET Cape Canaveral
  TRACK 0.00 0.00
END_MFD

BEGIN_PANEL
END_PANEL


BEGIN_SHIPS
ISS:ProjectAlpha_ISS
  STATUS Orbiting Earth
  RPOS -6513138.66 1474134.35 846490.25
  RVEL 1344.637 7214.008 -2296.334
  AROT 109.61 -8.53 80.06
  PRPLEVEL 0:1.000
  DOCKINFO 0:0,GL-01
  IDS 0:588 100 1:586 100 2:584 100 3:582 100 4:580 100
  NAVFREQ 0 0
  XPDR 466
  FLIGHTDATA
END
Mir
  STATUS Orbiting Earth
  RPOS -5049474.47 265160.99 4344030.86
  RVEL -5037.901 -357.832 -5851.913
  AROT 0.00 -45.00 90.00
  IDS 0:540 100 1:542 100 2:544 100
  XPDR 482
  FLIGHTDATA
END
GL-01:DeltaGliderIII
  STATUS Orbiting Earth
  RPOS -6513140.98 1474159.39 846482.56
  RVEL 1344.637 7214.008 -2296.334
  AROT -70.39 8.53 -80.06
  RCSMODE 2
  PRPLEVEL 0:1.000 1:1.000 2:0.983
  DOCKINFO 0:0,ISS
  NAVFREQ 466 588
  XPDR 0
  FLIGHTDATA
  MeshSkin DeltaGliderIIITransworld
  NOSECONE 1 1.0000
  GEAR 0 0.0000
  AIRLOCK 0 0.0000
  INNERDOOR 0 0.0000
  COCKPIT 0 0.0000
  PRADIATOR_PROC 0 0.0000
  ANTENNA_PROC 0
  StartPower_ext 0
  StartPower_batt 0
  StartPower_cell 0
  Apu_start 2
  Gen1 2
  Gen2 2
  GenSelector 1
  PowerHud 2
  PowerMfd 2
  PowerRadio 2
  PowerAirlock 2
  PowerEngine 2
  PowerLifepack 2
  PowerAp 2
  PowerMainBus 2
  PassengerSeat 1
  Strobe 1
  HydGearPress 0
  LevelBatt 100.0002
  Emergency_power 10000.0000
  Force_Canopy 0
  VoltageStartBus 0.0000
  VoltageGen1 96.2820
  VoltageGen2 96.2819
  VoltageGenBus 96.2820
  ExtFuelHatch 0
  ExtFuelValve 0
  DockFuelValve 0
  FuelInputSelector 0
  XFeedFuel 0
  DumpMainFuel 0
  DumpRcsFuel 0
  HoverValve 2
  MainValveL 2
  MainValveR 2
  RcsValve 2
  AirIntake 0
  TurboPump 0
  ComputerDisplay 1
  HudMode 0
  O2tankALevel 93.0527
  N2tankALevel 100.0000
  O2tankBLevel 100.0000
  N2tankBLevel 100.0000
  DockInputValve 2
  ExtInputValve 0
  InputSelector 2
  ButtonTankAO2 2
  ButtonTankAN2 1
  ButtonTankBO2 2
  ButtonTankBN2 1
  ButtonAFan 2
  ButtonAFilter 2
  ButtonACooling 2
  ButtonAMoist 2
  ButtonBFan 2
  ButtonBFilter 2
  ButtonBCooling 2
  ButtonBMoist 2
  Radiator 0
  ShipControl 3
  LifeDisplay 3
  CabinO2Level 21.3902
  CabinCO2Level 600.0001
  CabinTempLevel 21.2000
  CabinPressure 14.7000
  CabinMoistLevel 36.0000
  CabinDustLevel -0.0001
  CabinO2Setting 21.4000
  CabinTempSetting 21.2000
  CabinPressSetting 14.7000
  O2ConsumptionSetting 1
  AntennaTarget no_target
  NoOneOnBoard 0
  NoPilotOnBoard 0
  PassengerNumber 4
  PilotName Capt_John_Doe
  PilotAge 37
  BasePilotPulse 60.0000
  Passenger1Name Bevan_Aneurin
  Passenger1Age 27
  Passenger1BasePulse 66.0000
  Passenger2Name Capt_Antonio_Rodriguez
  Passenger2Age 20
  Passenger2BasePulse 72.0000
  Passenger3Name Bundy_McGeorge
  Passenger3Age 36
  Passenger3BasePulse 65.0000
  Passenger4Name Megnes_Julien
  Passenger4Age 20
  Passenger4BasePulse 72.0000
  FailGearFailure 0
  FailGearCollapse 0
  FailLeftMainEngine 0
  FailRightMainEngine 0
  FailHoverEngine 0
  FailRcs 0
  FailSurfaceControl 0
  FailComputer 0
  FailComputerBlueScreen 0
  FailAutopilot 0
  FailExtRadiator 0
  FailAirbrake 0
  FailNoseCone 0
  FailCanopy 0
  FailAntenna 0
END
SH-03:ShuttleA
  STATUS Landed Earth
  POS -82.4982414 22.9994604
  HEADING 70.00
  PRPLEVEL 0:1.000 1:1.000
  NAVFREQ 0 0
  XPDR 0
  FLIGHTDATA
  PODANGLE 0.0000 0.0000
  DOCKSTATE 0 0.0000
  AIRLOCK 0 0.0000
  GEAR 0 0.0000
  PAYLOAD MASS 0.0 0
END
GL-02:DeltaGlider
  STATUS Landed Mars
  BASE Olympus:3
  POS -135.4300000 12.7366195
  HEADING 0.00
  PRPLEVEL 0:1.000 1:1.000
  NAVFREQ 0 0 0 0
  XPDR 0
  FLIGHTDATA
  GEAR 1 1.0000
END
SH-01:ShuttleA
  STATUS Landed Moon
  BASE Brighton Beach:1
  POS -33.4374999 41.1184067
  HEADING 0.00
  PRPLEVEL 0:1.000 1:1.000
  NAVFREQ 0 0
  XPDR 0
  FLIGHTDATA
  PODANGLE 0.0000 0.0000
  DOCKSTATE 0 0.0000
  AIRLOCK 0 0.0000
  GEAR 0 0.0000
  PAYLOAD MASS 0.0 0
END
END_SHIPS

BEGIN_ExtMFD
END




Tell me if it helps.

[Tragamin]

tried it, still didnt work i still never re-entered properly even after following guides i end up around 1000 kilometres
from cape canaveral

[jamesc]

The problem to me seems to be the initial state vectors.  When I look at them in the scenario editor, I'm showing the
orbit as a very large eccentric hyperbola racing off into space!




ISS:ProjectAlpha_ISS


STATUS Orbiting Earth


RPOS -6513138.66 1474134.35 846490.25


RVEL 1344.637 7214.008 -2296.334




State Vectors (left-handed)


x=-6513138.66 m


y=1474134.35


z=846490.25




xdot=1344.637


ydot=7214.008


zdot=-2296.334




Elements (wrt ecliptic reference body):


SmA=-443952.7272 (!)


Ecc=331882.816 (!!!!)


Inc=0.01091515013 deg






Wow!




Can you please check this out, or perhaps give us Epoch/Elements for the starting state of ISS?




When I run the program, my pilot/passengers in DG-III die quickly from Excessive G-Force (Velocity is showing






Thanks.

[jamesc]

Oh, wait I see the problem here...




The scenario file name ("Docked to ISS 002") is not the same name as the Flightdata Folder name.  I renamed the
scenario file to match, and it worked.  You might want to update the zip  file with the correct scenario name.

[Michelle Megan]

hmm my pics for the re-entry tutorial are gone  with my web site down I lost my hosting ability.

If someone is willing to host my pics for me old re-entry tutorial I can rework it. I still have to original pics somewhere.

maybe a folder I can use with ftp to redo the tutorial..

I did a perfect re-entry using my old method and it still works with Orbiter 2006.. got a lil hot near the end and had
some excessive Gs.. 2 passengers passed out for a bit but when it slowed down in the end I was real close to KSC
for a perfect landing all crew survived, no damage..

Of course there is still room for me to improve my re-entry proceedure and I plan to revise it to work a little better
with Orbiter 2006.

Once I have done so Ill take pics and make a new tutorial.. Maybe McBrain has a lil room for me on his site so I can
host the pics again

[Tragamin]

that fixed it for me jamesc, thanx