# OHMSpace Launch System for Orbiter 2016 0.1.2

#### Kyle

##### Armchair Astronaut
What runs out of fuel the Orion or SLS. Orion is a separate module. and SLS is really a cfg and mesh

SLS does - specifically, the ICPS is unable to reach the necessary dV for a TLI.
Could the BurnTime parameter be wrong? MS/MS2015 both use it to calculate the ISP, so if it's wrong you get the wrong the propellant efficiency and therefore the wrong performance from the stage. It would be nice if we could specify the ISP directly as the "burn time" term only really applies to solid propellant stages, not liquid propellant ones.
The Burn Time parameter is the one that is publicly available for the RL-10 and ICPS. This number should be valid.

27220 kg / 1125 s = 24.2 kg/s

111010 N / 24.2 kg/s = 4588 Ns/kg

Official specific impulse: 4530 Ns/kg

No, the ini file should perform slightly better than the real thing

Could be the public numbers are inaccurate? I remember reading that the ICPS is slightly stretched vs the one used on the Delta IV. Maybe these numbers are the ones for the Delta IV DCSS, not the ICPS.

#### Max-Q

##### 99 40
Saturn V was so much simpler! Entire spacecraft (CSM, LM) to TLI in one burn!

#### DaveS

Donator
Beta Tester
Could be the public numbers are inaccurate? I remember reading that the ICPS is slightly stretched vs the one used on the Delta IV. Maybe these numbers are the ones for the Delta IV DCSS, not the ICPS.
This is correct, the ICPS LH2 tank has an 18" stretch to accommodate more fuel compared to the stock 5m DCSS.

#### Kyle

##### Armchair Astronaut
This is correct, the ICPS LH2 tank has an 18" stretch to accommodate more fuel compared to the stock 5m DCSS.

That solves the mystery then. Looking at the ini files, the values for empty mass and fuel mass are for the 5m DCSS.

Code:
EmptyMass=3488.125
FuelMass=27220.000
Thrust=111010.000
BurnTime=1125.000
ignite_delay=10.000

NASA documents also list this (empty mass ~4,000 kg, fuel mass ~27,000 kg): https://ntrs.nasa.gov/api/citations/20120014495/downloads/20120014495.pdf

So it appears NASA's public info is not correct.

#### DaveS

Donator
Beta Tester
That solves the mystery then. Looking at the ini files, the values for empty mass and fuel mass are for the 5m DCSS.

Code:
EmptyMass=3488.125
FuelMass=27220.000
Thrust=111010.000
BurnTime=1125.000
ignite_delay=10.000

NASA documents also list this (empty mass ~4,000 kg, fuel mass ~27,000 kg): https://ntrs.nasa.gov/api/citations/20120014495/downloads/20120014495.pdf

So it appears NASA's public info is not correct.
That's a pretty old document, predating even the Preliminary Design Review (PDR was in 2014) by several years. So nothing in that document really applies anymore.

#### Kyle

##### Armchair Astronaut
That's a pretty old document, predating even the Preliminary Design Review (PDR was in 2014) by several years. So nothing in that document really applies anymore.

Yeah, annoying how that was the only easily accessible figures I could find on the ICPS.

I did these values from SpaceFlightInsider

3490 kg empty mass, 28576 kg fuel mass. However, this still falls far short of the needed fuel for a TLI. I have to entirely deplete Orion's fuel to get into the right trajectory.

#### DaveS

Donator
Beta Tester
As far as trajectory is concerned, this is still the latest for Artemis-1 (formerly Exploration Mission-1, or EM-1): https://www.nasaspaceflight.com/2016/07/mission-trajectory-sarafin-outlines-ride-uphill-em-1/

Core Stage to 1805 kmX40 km sub-orbit for disposal. RS-25 throttle buckets between 60 to 80-90 seconds and near CS MECO to limit loads. ESM panel jettison at 3:20, with LAS jettison 25 seconds later (3:45). CS MECO at 8:10 or so. ICPS burn to up the perigee to 185 km. TLI approx. 90 minutes later after SECO-1.

#### Kyle

##### Armchair Astronaut
Alright, good values. I was starting from a circular 200 kilometer orbit. Makes sense to have the SLS do a little bit more work than that. I changed the post-SECO orbit to those values, and I have a total dV requirement of about ~3200 m/s for a burn time of 1,193 seconds for a TLI burn, so I'm still falling short.

#### DaveS

Donator
Beta Tester
Here's what might be a stupid question, but are you launching during an actual viable launch window? SLS only have a 2-hour launch window every day during a certain launch period. If you miss those daily launch windows during that launch period, you have to wait until the next launch period.

#### DaveS

Donator
Beta Tester
That solves the mystery then. Looking at the ini files, the values for empty mass and fuel mass are for the 5m DCSS.

Code:
EmptyMass=3488.125
FuelMass=27220.000
Thrust=111010.000
BurnTime=1125.000
ignite_delay=10.000

NASA documents also list this (empty mass ~4,000 kg, fuel mass ~27,000 kg): https://ntrs.nasa.gov/api/citations/20120014495/downloads/20120014495.pdf

So it appears NASA's public info is not correct.
This is from the official Payload Planner's Guide for the Delta IV EELV:

The 5-m second stage is based on the 4-m version. The LO2 tank is lengthened by approximately 0.5 m, while the LH2 tank’s diameter is enlarged to 5 m. The total propellant load increases to 27,200 kg (60,000 lb), allowing a burn time of over 1,125 sec.

So NASA SLS document specifies an unmodified 5-m DCSS. So both the burn time and propellant/empty masses needs to be updated to reflect the LH2 tank stretch.

#### Kyle

##### Armchair Astronaut
Here's what might be a stupid question, but are you launching during an actual viable launch window? SLS only have a 2-hour launch window every day during a certain launch period. If you miss those daily launch windows during that launch period, you have to wait until the next launch period.

Definitely not a dumb question, as an off-plane intercept would have a significant dV penalty. I did check and I was a little off-plane for that scenario. I now have the dV down to about 2737 m/s.

Given we don't know the date or time Artemis 1 is planning to launch, I'm going with a Nov. 1, 2021 launch date. I have the T-0 at around 09:49 UTC for a lunar intercept at MET+110 hours.

Using the values above, I am roughly 1,290 m/s short of dV. This is a huge shortfall. So we'll have to guesstimate the new burntime and gross mass. Do we know how long the TLI burn will be for Artemis 1?

Last edited:

#### DaveS

Donator
Beta Tester
Definitely not a dumb question, as an off-plane intercept would have a significant dV penalty. I did check and I was a little off-plane for that scenario. I now have the dV down to about 2737 m/s.

Given we don't know the date or time Artemis 1 is planning to launch, I'm going with a Nov. 1, 2021 launch date. I have the T-0 at around 09:49 UTC for a lunar intercept at MET+110 hours.

Using the values above, I am roughly 1,290 m/s short of dV. This is a huge shortfall. So we'll have to guesstimate the new burntime and gross mass. Do we know how long the TLI burn will be for Artemis 1?
I have November 22 this year as the opening of the launch period. According to this graphic, the TLI burn should last around 20 minutes.

#### Urwumpe

##### Not funny anymore
Donator
According to the plots in the trajectory paper, the Total DV, that the ICPS stage should provide in a mission, goes from less than 2850 to 2950. The likely optimum launch scenario should be at about 2900 m/s for the ICPS, then the Orion spacecraft needs to provide about 650 m/s DV for the mission.

#### DaveS

Donator
Beta Tester
After a bit of experimenting, I have come up with these two files for EM-1. The first one is a new GNC file, which should be more accurate with the caveat that you ride the Core Stage into the parking orbit. The second one is the actual MS2015 vessel definition file for EM-1 with some corrections made to the SRBs, Core Stage and ICPS masses, thrust and burn times. With these changes I was able to send Orion on a trans-lunar trajectory with propellant to spare (not much but some).

SLS_EM1_Orion_GNC.txt
Code:
Multistage 2015 Automatically Generated Guidance File
Vehicle: SLS
-10.000 =orbit(185.00,1850.00,-29.62,-1.00,75.70,0.00)
-5.000 =engine(0.00,100.00,5.00,0.00,0.00,0.00)
200.000 =fairing()
225.000 =les()
60.000 =engine(100.00,58.00,3.00,0.00,0.00,0.00)
80.000 =engine(58.00,100.00,3.00,0.00,0.00,0.00)
400.00 =engine(100.00,58.00,30.00,0.00,0.00,0.00)

SLS_BLOCKIAORION_day.ini
Code:
[MISC]
cog=25.000
GNC_Debug=0
Telemetry=0
Focus=1
Thrust_real_pos=0
Vertical_Angle=0.000

[TEXTURE_LIST]
TEX_1=Exhaust_atsme
TEX_2=SLS_2016\SSME_Exhaust

[PARTICLESTREAM_1]
Name=vent
amin =1e-006
amax =1.000
atmslowdown =4.000
growthrate =1.900
lmax =0.500
lmin =0
srcrate =8.000
srcsize =0.400
v0 =0.500
ltype =EMISSIVE
atmsmap =ATM_PLOG
levelmap =LVL_PSQRT
tex =contrail
GrowFactor_size=20.000
GrowFactor_rate=8.000

[PARTICLESTREAM_2]
NAME=mach
SRCSIZE=12
SRCRATE=20
V0=50.1
GROWTHRATE=10
ATMSLOWDOWN=0
LTYPE=EMISSIVE
LEVELMAP=LVL_PSQRT
LMIN=0
LMAX=4
ATMSMAP=ATM_PLOG
AMIN=0.7e-7
AMAX=1
TEX= contrail

[PARTICLESTREAM_3]
Name=EMISSIVE_contrail
Srcsize=12.000
Srcrate=35.000
V0=300.000
Growthrate=6.000
Atmslowdown=1.300
Ltype=EMISSIVE
Levelmap=LVL_PSQRT
Lmin=0.8
Lmax=9.000
Atmsmap=ATM_PLOG
Amin=1e-006
Amax=1.000
Tex=SLS_2016/SLS_SRB_contrail
GrowFactor_size=1.400
GrowFactor_rate=4.000

[PARTICLESTREAM_4]
Name=SRB_exhaust
Srcsize=2.500
Srcrate=200.000
V0=100.000
Growthrate=11.000
Atmslowdown=0.300
Ltype=EMISSIVE
Levelmap=LVL_PSQRT
Lmin=0
Lmax=1.000
Atmsmap=ATM_PLOG
Amin=1e-006
Amax=1.000
Tex=SLS_2016/SLS_SRB_exhaust
GrowFactor_size=1.100
GrowFactor_rate=2.000

[PARTICLESTREAM_5]
Name=DIFFUSE_contrail
Srcsize=10.000
Srcrate=40.000
V0=300.000
Growthrate=6.000
Atmslowdown=1.300
Ltype=DIFFUSE
Levelmap=LVL_PSQRT
Lmin=0.8
Lmax=9.000
Atmsmap=ATM_PLOG
Amin=1e-006
Amax=1.000
Tex=SLS_2016/SLS_SRB_contrail
GrowFactor_size=1.400
GrowFactor_rate=4.000

[PARTICLESTREAM_6]
Name=Launchfx
Srcsize=10.000
Srcrate=30.000
V0=170.000
Growthrate=10.000
Atmslowdown=0.300
Ltype=EMISSIVE
Levelmap=LVL_PSQRT
Lmin=0.8
Lmax=1.000
Atmsmap=ATM_PLOG
Amin=1e-006
Amax=1.000
Tex=SLS_2016/SLS_SRB_contrail

[PARTICLESTREAM_8]
Name=Exhdetail
Srcsize=0.700
Srcrate=10.000
V0=50.4
Growthrate=0.000
Atmslowdown=0.100
Ltype=EMISSIVE
Levelmap=LVL_FLAT
Lmin=1
Lmax=1.000
Atmsmap=ATM_FLAT
Amin=1
Amax=1.000
Tex=SLS_2016\SSME_Exhaust_Detail

[PARTICLESTREAM_9]
Name=Ice
Srcsize=0.150
Srcrate=0.500
V0=10.000
Growthrate=0.000
Atmslowdown=0.000
Ltype=EMISSIVE
Levelmap=LVL_PSQRT
Lmin=0
Lmax=1.000
Atmsmap=ATM_PLOG
Amin=1
Amax=1.000
Tex=SLS_2016/Ice_Part

[PARTICLESTREAM_10]
Name=Ice2
Srcsize=0.050
Srcrate=1.500
V0=10.000
Growthrate=0.000
Atmslowdown=0.000
Ltype=EMISSIVE
Levelmap=LVL_PSQRT
Lmin=0
Lmax=1.000
Atmsmap=ATM_PLOG
Amin=1
Amax=1.000
Tex=SLS_2016/Ice_Part

[PARTICLESTREAM_11]
Name=Exhdetail2
Srcsize=1.000
Srcrate=10.000
V0=0.001
Growthrate=0.000
Atmslowdown=0.100
Ltype=EMISSIVE
Levelmap=LVL_FLAT
Lmin=1
Lmax=1.000
Atmsmap=ATM_FLAT
Amin=1
Amax=1.000
Tex=SLS_2016\SSME_Exhaust_Detail

[PARTICLESTREAM_12]
Name=SRB_exhaust_2
Srcsize=5.000
Srcrate=200.000
V0=400.000
Growthrate=35.000
Atmslowdown=0.300
Ltype=EMISSIVE
Levelmap=LVL_PSQRT
Lmin=0
Lmax=1.000
Atmsmap=ATM_PLOG
Amin=1e-006
Amax=1.000
Tex=SLS_2016/SLS_SRB_exhaust
GrowFactor_size=1.400
GrowFactor_rate=4.000

[PARTICLESTREAM_13]
Name=Engdetail
Srcsize=1.200
Srcrate=20.000
V0=0.100
Growthrate=0.000
Atmslowdown=0.000
Ltype=EMISSIVE
Levelmap=LVL_FLAT
Lmin=0.3
Lmax=1.000
Atmsmap=ATM_FLAT
Amin=0.3
Amax=1.000
Tex=SLS_2016/Ice_Part

[PARTICLESTREAM_7]
Name=Engdetail_2
Srcsize=0.800
Srcrate=5.000
V0=60.001
Growthrate=0.000
Atmslowdown=0.100
Ltype=EMISSIVE
Levelmap=LVL_FLAT
Lmin=1
Lmax=1.000
Atmsmap=ATM_FLAT
Amin=1
Amax=1.000
Tex=SLS_2016\SSME_Exhaust_Detail

[FX_LAUNCH]
N=2
Height=10.000
Angle=90.000
Distance=0.000
CutoffAltitude=800.000
Pstream1=launchfx
Pstream2=launchfx2

[FX_VENT]
pstream=vent
off_1=(4.200,-1.000,30.000)
dir_1=(1.000,5.000,0.000)
time_fin_1=-5.000
off_2=(1.000,-4.200,15.000)
dir_2=(5.000,1.000,0.000)
time_fin_2=-5.000

[FX_MACH]
pstream=mach
mach_min=0.900
mach_max=1.300
off_1=(-1.000,0.000,18.000)
off_2=(1.000,0.000,18.000)
off_3=(-5.000,0.000,5.000)
dir=(0.000,0.000,-1.000)
Off_4=(5.000,0.000,5.000)
Off_5=(0.000,0.000,30.000)

[BOOSTER_1]
N=1
MeshName=SLS_2016\Orange-booster_s
Height=53.900
Diameter=3.710
EmptyMass=86363.600
FuelMass=643920.1
Thrust=14652000.00
angle=0.000
off=(6.300,0.000,-0.300)
BurnTime=126.000
eng_1=(0.000,0.000,-28.000)
eng_diameter=0.010
ENG_PSTREAM1=srb_exhaust
Speed=(15.000,-4.000,0.000)
Rot_speed=(-0.200,-0.400,0.000)
Eng_tex=
Eng_pstream1=SRB_exhaust
Eng_pstream2=srb_exhaust_2
BurnDelay=0.000
Expbolts_pos=(6.450,0.000,19.000)
Expbolts_pstream=exbolt
Expbolts_anticipation=1.000

[BOOSTER_2]
N=1
Angle=0.000
Meshname=SLS_2016\Orange-booster_sl
Off=(-6.300,0.000,-0.300)
Height=53.900
Diameter=3.710
Thrust=14652000.00
EmptyMass=86363.600
FuelMass=643920.1
Burntime=126.000
Eng_diameter=0.010
Eng_tex=
Eng_pstream1=srb_exhaust
Eng_pstream2=srb_exhaust_2
Speed=(-15.000,-4.000,0.000)
Rot_speed=(-0.200,0.400,0.000)
Eng_1=(0.000,0.000,-28.000)
BurnDelay=0.000
Expbolts_pos=(-6.450,0.000,19.000)
Expbolts_pstream=exbolt
Expbolts_anticipation=1.000

[BOOSTER_3]
N=2
Angle=0.000
Meshname=SLS_2016\dummy
Off=(6.300,0.000,0.000)
Height=0.001
Diameter=0.001
Thrust=0.001
EmptyMass=0.100
FuelMass=0.100
Burntime=126.000
Eng_diameter=0.010
Eng_tex=
Eng_pstream1=diffuse_contrail
Eng_pstream2=emissive_contrail
Speed=(0.000,0.000,0.000)
Rot_speed=(0.000,0.000,0.000)
Eng_1=(0.000,0.000,-90.000)
Eng_2=(0.000,0.000,-90.000)
BurnDelay=0.000

[BOOSTER_4]
N=3
Angle=90.000
Meshname=SLS_2016\dummy
Off=(2.200,0.000,25.000)
Height=0.001
Diameter=0.001
Thrust=0.001
EmptyMass=0.100
FuelMass=0.100
Burntime=15.000
BurnDelay=0.000
eng_1=(2.000,0.000,2.500)
Eng_diameter=0.000
Eng_tex=
Eng_pstream1=ice
Eng_pstream2=ice2
Speed=(0.000,0.000,0.000)
Rot_speed=(0.000,0.000,0.000)
Eng_2=(1.000,3.000,0.000)
Eng_3=(2.000,1.700,5.000)
Eng_4=(2.000,-0.200,-2.500)

[BOOSTER_5]
N=1
Angle=0.000
Meshname=SLS_2016\dummy
Off=(0.000,0.000,0.000)
Height=0.001
Diameter=0.001
Thrust=0.001
EmptyMass=0.100
FuelMass=0.100
Burntime=441.000
BurnDelay=0.000
Eng_diameter=0.000
Eng_tex=
Eng_pstream1=exhdetail
Eng_pstream2=
Speed=(0.000,0.000,0.000)
Rot_speed=(0.000,0.000,0.000)
eng_1=(-2.300,2.300,-48.000)
eng_2=(-2.300,-2.300,-48.000)
eng_3=(2.300,-2.300,-48.000)
eng_4=(2.300,2.300,-48.000)

[BOOSTER_6]
N=1
Angle=0.000
Meshname=SLS_2016\dummy
Off=(0.000,0.000,0.000)
Height=0.001
Diameter=0.001
Thrust=0.001
EmptyMass=0.100
FuelMass=0.100
Burntime=441.000
BurnDelay=0.000
Eng_diameter=0.000
Eng_tex=
Eng_pstream1=exhdetail2
Eng_pstream2=
Speed=(0.000,0.000,0.000)
Rot_speed=(0.000,0.000,0.000)
eng_1=(-2.300,2.300,-46.208)
eng_2=(-2.300,-2.300,-46.208)
eng_3=(2.300,-2.300,-46.208)
eng_4=(2.300,2.300,-46.208)

[STAGE_1]
Height=63.720
Diameter=8.400
EmptyMass=85275.392
FuelMass=987470.6 ; Corrected propellant masses, 143,788.8 kg LOX/843,681.8 kg LH2
Thrust=9115296.86564; Corrected total thrust, 4xRS-25D at 109% RPL (100%=2090664.159 N)
BurnTime=481.5; Nominal vaccuum ISP RS-25D 4442.6 m/s, this approximates this
off=(0.000,0.000,4.700)
MeshName=SLS_2016\corerustET_1a_orion
eng_1=(-2.300,2.300,-32.208)
eng_2=(-2.300,-2.300,-32.208)
eng_3=(2.300,-2.300,-32.208)
eng_4=(2.300,2.300,-32.208)
eng_diameter=2.400
PITCHTHRUST=14193633.100
YAWTHRUST=14193633.100
speed=(0.000,0.000,-2.000)
ENG_PSTREAM1=engdetail_2
battery=1.500
Reignitable=0
Eng_tex=SLS_2016\SSME_Exhaust
Eng_pstream2=engdetail
Eng_dir=(0.000,0.000,1.000)
Module=Stage
Rot_speed=(0.000,0.000,0.000)

[STAGE_2]
MeshName=SLS_2016\SLS_ICPS2
Diameter=5.000
Height=13.700
EmptyMass=3488.125
FuelMass=27220.08
Thrust=110100.000
BurnTime=1150.0
ignite_delay=10.000
PitchThrust=1100
YawThrust=1100
RollThrust=1100
off=(0.000,0.000,42.950)
eng_1=(0.000,0.000,-6.500)
eng_diameter=2.700
ullage_thrust=10000.000
ullage_N=4
ullage_angle=-22.500
ullage_pos=(4.200,0.000,-10.700)
ullage_dir=(0.200,0.000,-1.000)
ullage_tex=Exhaust_atsme
ullage_length=5.000
ullage_diameter=1.000
ullage_anticipation=3.000
ullage_overlap=1.000
ullage_rectfactor=3.000
reignitable=1
Eng_tex=
Eng_pstream1=Engdetail_2
Eng_pstream2=Engdetail
Eng_dir=(0.000,0.000,1.000)
Module=Stage
Speed=(0.000,0.000,2.000)
Rot_speed=(0.000,0.000,0.000)

[FAIRING]
Meshname=SLS_2016\SLSORIONMPCVFAIR
Off=(0.000,0.000,51.600)
N=3
Angle=90.000
Height=6.000
Diameter=8.000
EmptyMass=1383.000
Module=stage
Speed=(8.000,0.000,0.000)
Rot_Speed=(0.700,0.000,0.000)

[LES]
Meshname=Orion-MPCV\orion-las-tweaked
Off=(0.000,0.000,53.120)
Height=13.000
Diameter=5.000
EmptyMass=5044.000
Module=stage
Speed=(0.000,-4.000,50.000)
Rot_speed=(0.000,0.400,0.000)

MeshName=Orion-MPCV\orion-launch-white
off=(0.000,0.000,53.240)
Diameter=5.000
Height=8.000
MASS=23820.000
Module=Orion-MPCV\Orion-MPCV
Name=Orion
SPEED=(0.000,0.000,2.000)
RENDER=1
Rotation=(0.000,0.000,0.000)
Rot_speed=(0.000,0.000,0.000)
Live=1

Meshname=SLS_2016\Cubesat6U_ICECUBE
Off=(0.000,-1.411,49.140)
Rotation=(90,31,90)
Height=0.130
Diameter=0.100
Mass=13.000
Module=spacecraft\spacecraft4
Name=Cubesat6U_ICECUBE
Speed=(0.000,1.500,3.000)
Rot_speed=(0.000,0.000,0.000)
Render=1
Live=1

Meshname=SLS_2016\Cubesat6U_NEA
Off=(0.010,1.411,49.140)
Rotation=(90,-31,90)
Height=0.130
Diameter=0.100
Mass=13.000
Module=spacecraft\spacecraft4
Name=Cubesat6U_NEA
Speed=(0.000,-1.500,3.000)
Rot_speed=(0.000,0.000,0.000)
Render=1
Live=1

#### Kyle

##### Armchair Astronaut
Thanks Dave,

That looks good to me as well. Looks like enough fuel to do the disposal burn that was mentioned as part of the flight plan too.

#### Mr. Residuals

##### 50 18
SLS_BLOCKIAORION_day.ini
Wait, so this is not included and you have to make one right?

#### Longjap

##### Active member
Since the SLS is stacked and out the FAB and we can see how it really looks, I'm currently revisiting the 3D model to make it more detailed and according the pictures I have.

#### Longjap

##### Active member
Currently texturing the tank from real pictures. Lord, this is some tedious work. Will try normal / bump mapping next. But my modeling skills are a bit rusty after 6 years. Forgot how to use the mesh wizard, got a ton of errors. Finally got it all loaded in the sim.

#### N_Molson

Donator
Looks very good and will be excellent with bump mapping ! Great work !

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