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 12-25-2011, 06:54 AM #31 Pipcard mikusingularity Quote: Originally Posted by Arrowstar  Couldn't tell you. What I do see is that if we put the Cook into an equatorial orbit (radius 7000 km), it'll only take 3.5 km/s of dV to escape Earth orbit: Code: ```Computing Departure Burn...Done! Burn Delta-V is 3.5602 km/s. Burn should be performed at true anomaly of 173.3137 degrees of pre-departure orbit. Burn Vector is as follows: --J2000 X Component: -0.39291 km/s --J2000 Y Component: -3.3516 km/s --J2000 Z Component: 1.1345 km/s --V Component: 3.3746 km/s --N Component: 1.1345 km/s --C Component: 5.5511e-017 km/s Hyperbolic Departure Orbital Elements are: --Semi-major Axis: -59839.1693 km --Eccentricity: 1.117 --Inclination: 5.9307 deg --Right Asc of Asc Node: 173.3137 deg --Argument of Periapse: 0 deg Constraint Error is 0. ##################################################################``` If we place it into a 28.5 degree circular orbit (same 7000 km radius), we get the following: Code: ```Computing Departure Burn...Done! Burn Delta-V is 6.3602 km/s. Burn should be performed at true anomaly of 171.9502 degrees of pre-departure orbit. Burn Vector is as follows: --J2000 X Component: -0.21482 km/s --J2000 Y Component: -4.2801 km/s --J2000 Z Component: 4.6996 km/s --V Component: 1.5341 km/s --N Component: 6.1724 km/s --C Component: 4.9405e-015 km/s Hyperbolic Departure Orbital Elements are: --Semi-major Axis: -59839.1693 km --Eccentricity: 1.117 --Inclination: 7.0681 deg --Right Asc of Asc Node: 140.2245 deg --Argument of Periapse: 32.8896 deg Constraint Error is 0. ##################################################################``` It pays to keep the Cook in an equatorial orbit unless its so overpowered that it can stand to lose 3 km/s of dV. But I'd rather launch more rockets to the Cook from Earth for supply and whatnot, and provide the Cook with dV margin. But, as usual, its up to the managers. But doesn't that mostly depend on the longitude of the ascending node, not the inclination?
 12-25-2011, 06:56 AM #32 Arrowstar Probenaut I've been setting RAAN to 0 degrees for these studies (as I was primarily interested in the effect of inclination, as that impacts launch site), but I can shift RAAN around too and see what happens. I'll do that after Christmas, as its late here now!
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 12-25-2011, 07:12 PM #33 flytandem Tutorial Publisher I have limited understanding of the numbers being crunched here, but I did hop into the cockpit with coffee in hand this morning while family were opening presents and started with the Dec 25 2017 suggested start date and visual understanding of an inward eject to Mars for a sling back to Earth 17 months later. I tweaked it to get the sling at Mars as close as comfortable and came up with an eject deltaV of 5579 m/s from a 200-200 km agl orbit that had a due east launch heading from the Cape. The sling at Mars is retrograde with Pe at about 248 km agl. I have a couple of scenarios below, the first is the scenario (TransX) from the ground up, ready for launch and the second is from the parking orbit with the eject maneuver ready to burn. ready for launch... Code: ```BEGIN_DESC END_DESC BEGIN_ENVIRONMENT System Sol Date MJD 58112.4121870860 END_ENVIRONMENT BEGIN_FOCUS Ship 3 END_FOCUS BEGIN_CAMERA TARGET 3 MODE Cockpit FOV 60.00 END_CAMERA BEGIN_HUD TYPE Surface END_HUD BEGIN_MFD Left TYPE User MODE TransX Ship 3 FNumber 5 Int 1 Orbit True Vector -5294006.85645 2082335.91523 2868304.32608 Vector -131.500119642 153.923118837 -354.454080865 Double 3.98600439969e+014 Double 58112.412187 Handle Earth Handle NULL Handle NULL Select Target 0 Escape Autoplan 0 0 Plan type 0 0 Plan 0 1 Plan 0 0 Plan 0 0 Select Minor 0 None Manoeuvre mode 0 0 Base Orbit 0 0 Prograde vel. 0 0 Man. date 0 58112.412187 Outward vel. 0 0 Ch. plane vel. 0 0 Intercept with 0 0 Orbits to Icept 0 0 Graph projection 0 3 Scale to view 0 0 Advanced 0 0 Pe Distance 0 6571244.85262 Ej Orientation 2 0.435599274713 Equatorial view 0 0 Finvars Finish BaseFunction Int 2 Orbit False Handle Sun Handle Earth Handle Mars Select Target 0 Mars Autoplan 0 0 Plan type 0 2 Plan 0 0 Plan 0 0 Plan 0 1 Select Minor 0 None Manoeuvre mode 0 0 Base Orbit 0 1 Prograde vel. 0 0 Man. date 0 58112.4121631 Outward vel. 0 0 Ch. plane vel. 0 0 Intercept with 0 0 Orbits to Icept 0 0 Graph projection 0 0 Scale to view 0 0 Advanced 0 0 Prograde vel. 0 1453.7004971 Eject date 2 58112.4732801 Outward vel. 3 -7110.94024409 Ch. plane vel. 3 -2280.15635591 Finvars Finish BaseFunction Int 4 Orbit True Vector 260091473.417 1089662522.58 6096197022.11 Vector -314.578298454 -1340.10620713 -7485.83425194 Double 4.28282991638e+013 Double 58307.8576671 Handle Mars Handle NULL Handle NULL Select Target 0 Escape Autoplan 0 0 Plan type 0 1 Plan 0 0 Plan 0 1 Plan 0 0 Select Minor 0 None Manoeuvre mode 0 0 Base Orbit 0 0 Prograde vel. 0 0 Man. date 0 58112.412187 Outward vel. 0 0 Ch. plane vel. 0 0 Intercept with 0 0 Orbits to Icept 0 0 Graph projection 0 0 Scale to view 0 0 Advanced 0 0 View Orbit 0 0 Finvars Finish BaseFunction Int 3 Orbit True Vector 100036396735 -6337262217.16 -185011493377 Vector 19566.7232022 -524.849486004 6478.52922727 Double 1.32712482783e+020 Double 58317.2762728 Handle Sun Handle Mars Handle Earth Select Target 0 Earth Autoplan 0 0 Plan type 0 2 Plan 0 0 Plan 0 0 Plan 0 2 Select Minor 0 None Manoeuvre mode 0 0 Base Orbit 0 0 Prograde vel. 0 0 Man. date 0 58112.412161 Outward vel. 0 0 Ch. plane vel. 0 0 Intercept with 0 0 Orbits to Icept 0 1 Graph projection 0 0 Scale to view 0 0 Advanced 0 0 Velocity. 0 0 Outward angle 2 2.47528144665 Inc. angle 3 0.0217370286361 Inherit Vel. 0 0 Eject date 0 58317.2762728 Finvars Finish BaseFunction Int 5 Orbit True Vector 5180904390.99 857007312.812 7424844268.48 Vector -6146.80883306 -1016.89450704 -8789.16811499 Double 3.98600439969e+014 Double 58616.5200428 Handle Earth Handle NULL Handle NULL Select Target 0 None Autoplan 0 0 Plan type 0 1 Plan 0 0 Plan 0 2 Plan 0 0 Select Minor 0 None Manoeuvre mode 0 0 Base Orbit 0 0 Prograde vel. 0 0 Man. date 0 58112.4121571 Outward vel. 0 0 Ch. plane vel. 0 0 Intercept with 0 0 Orbits to Icept 0 0 Graph projection 0 0 Scale to view 0 0 Advanced 0 0 Draw Base 0 0 Finvars Finish BaseFunction END_MFD BEGIN_MFD Right TYPE User MODE TransX END_MFD BEGIN_SHIPS 3:DeltaGlider STATUS Landed Earth BASE Cape Canaveral:1 POS -80.6758964 28.5227640 HEADING 90.00 RCSMODE 0 AFCMODE 7 PRPLEVEL 0:1.000000 1:1.000000 NAVFREQ 0 524 84 114 XPDR 6 GEAR 1 1.0000 PSNGR 2 3 4 TRIM 1.000000 AAP 0:0 0:0 0:0 END END_SHIPS BEGIN_VistaBoost END``` and ready for the eject burn... Code: ```BEGIN_DESC A burn of 5579 m/s needed for the eject. END_DESC BEGIN_ENVIRONMENT System Sol Date MJD 58112.4670673098 END_ENVIRONMENT BEGIN_FOCUS Ship 3 END_FOCUS BEGIN_CAMERA TARGET 3 MODE Cockpit FOV 29.59 END_CAMERA BEGIN_HUD TYPE Orbit REF AUTO END_HUD BEGIN_MFD Left TYPE User MODE TransX Ship 3 FNumber 5 Int 1 Orbit True Vector 198376.971889 -1662186.26583 6354168.71698 Vector -6931.96768778 3376.31624594 1099.61480406 Double 3.98600439969e+014 Double 58112.4652397 Handle Earth Handle NULL Handle NULL Select Target 0 Escape Autoplan 0 0 Plan type 0 0 Plan 0 1 Plan 0 0 Plan 0 0 Select Minor 0 None Manoeuvre mode 0 1 Base Orbit 0 0 Prograde vel. 5 5578.54815698 Man. date 5 58112.4742297 Outward vel. 2 1 Ch. plane vel. 4 57.285 Intercept with 0 0 Orbits to Icept 0 0 Graph projection 0 1 Scale to view 0 0 Advanced 0 0 Pe Distance 0 6571244.85262 Ej Orientation 0 0.435599274713 Equatorial view 0 0 Finvars Finish BaseFunction Int 2 Orbit True Vector -9315345742.87 22111751.3404 146809040340 Vector -31196.7682674 2242.06255066 -9155.99487234 Double 1.32712838556e+020 Double 58112.474229 Handle Sun Handle Earth Handle Mars Select Target 0 Mars Autoplan 0 0 Plan type 0 2 Plan 0 0 Plan 0 0 Plan 0 1 Select Minor 0 None Manoeuvre mode 0 0 Base Orbit 0 0 Prograde vel. 0 0 Man. date 0 58112.4657363 Outward vel. 0 0 Ch. plane vel. 0 0 Intercept with 0 0 Orbits to Icept 0 0 Graph projection 0 0 Scale to view 0 0 Advanced 0 0 Prograde vel. 6 0 Eject date 0 58112.4732801 Outward vel. 6 0 Ch. plane vel. 6 0 Finvars Finish BaseFunction Int 4 Orbit True Vector 256207559.643 1077374677.49 6098386268.73 Vector -307.055288613 -1313.99803393 -7425.94396599 Double 4.28282991638e+013 Double 58308.3783381 Handle Mars Handle NULL Handle NULL Select Target 0 Escape Autoplan 0 0 Plan type 0 1 Plan 0 0 Plan 0 1 Plan 0 0 Select Minor 0 None Manoeuvre mode 0 0 Base Orbit 0 0 Prograde vel. 0 0 Man. date 0 58112.4665844 Outward vel. 0 0 Ch. plane vel. 0 0 Intercept with 0 0 Orbits to Icept 0 0 Graph projection 0 0 Scale to view 0 0 Advanced 0 0 View Orbit 0 0 Finvars Finish BaseFunction Int 3 Orbit True Vector 101187247954 -6350804814.7 -184303009972 Vector 19551.0700703 -527.423267935 6661.56154335 Double 1.32712482783e+020 Double 58317.8762348 Handle Sun Handle Mars Handle Earth Select Target 0 Earth Autoplan 0 0 Plan type 0 2 Plan 0 0 Plan 0 0 Plan 0 2 Select Minor 0 None Manoeuvre mode 0 0 Base Orbit 0 0 Prograde vel. 0 0 Man. date 0 58112.4670669 Outward vel. 0 0 Ch. plane vel. 0 0 Intercept with 0 0 Orbits to Icept 0 0 Graph projection 0 0 Scale to view 0 0 Advanced 0 0 Velocity. 0 0 Outward angle 3 2.48194860439 Inc. angle 0 0.0217370286361 Inherit Vel. 0 0 Eject date 0 58317.8762348 Finvars Finish BaseFunction Int 5 Orbit True Vector 5177247188.59 858982366.66 7427133654.97 Vector -6109.26882673 -1015.31563898 -8745.27100999 Double 3.98600439969e+014 Double 58616.422016 Handle Earth Handle NULL Handle NULL Select Target 0 None Autoplan 0 0 Plan type 0 1 Plan 0 0 Plan 0 2 Plan 0 0 Select Minor 0 None Manoeuvre mode 0 0 Base Orbit 0 0 Prograde vel. 0 0 Man. date 0 58112.4664868 Outward vel. 0 0 Ch. plane vel. 0 0 Intercept with 0 0 Orbits to Icept 0 0 Graph projection 0 0 Scale to view 0 0 Advanced 0 0 Draw Base 0 0 Finvars Finish BaseFunction END_MFD BEGIN_MFD Right TYPE User MODE TransX END_MFD BEGIN_SHIPS 3:DeltaGlider STATUS Orbiting Earth RPOS -893308.86 -1103123.34 6415822.11 RVEL -6854.658 3683.949 -321.010 AROT 146.42 34.56 146.92 AFCMODE 7 PRPLEVEL 0:0.594959 1:0.988044 NAVFREQ 0 524 84 114 XPDR 6 PSNGR 2 3 4 TRIM 1.000000 AAP 0:0 0:0 0:0 END END_SHIPS BEGIN_VistaBoost END``` Last edited by flytandem; 12-25-2011 at 07:15 PM. Reason: typo
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 12-25-2011, 08:27 PM #34 Arrowstar Probenaut Thanks, Flytandem! I'll check these out when I have time!
 12-25-2011, 08:39 PM #35 garyw O-F Administrator Quote: Originally Posted by Pipcard  How much Delta-V does the James Cook have? Can you take a look at that question and report back please pipcard?
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 12-25-2011, 08:42 PM #36 Arrowstar Probenaut Hey Gary, I need to know what kind of trajectories you want for the Mars missions. Should we do direct for the unmanned stuff and the free return for the manned mission(s)?
 12-25-2011, 09:36 PM #37 Pipcard mikusingularity Quote: Originally Posted by garyw  Can you take a look at that question and report back please pipcard? This doesn't make any sense (JamesCook.ini)... Code: ```EMPTY_MASS=350000 FUEL_MASS=2400000 ISP=150000``` When I plugged these numbers into http://www.strout.net/info/science/delta-v/, it gave me a huge value for Delta-V. (2832.09804 km/s) What are the units for that config file? What is the ISP actually supposed to be? 1500 seconds? (then I get a Delta-V of 28.32098 km/s, which sounds more reasonable). Keep in mind that this is for a James Cook with nothing docked to it (and if it burns all of its fuel at once). It's more than enough for a trip to Mars and back (or even two trips). I tried the same with the Deepstar. Code: ```EMPTY_MASS=20000 FUEL_MASS=300000 ISP=100000``` Assuming that the ISP is actually 1000, I get a Delta-V of 26.556 km/s (nothing docked to the Deepstar and if it burns all of its fuel at once). So the Deepstar actually has less dV than the Cook? ---------- Post added at 01:36 PM ---------- Previous post was at 01:27 PM ---------- Okay, I checked on Orbiter and I let the Cook burn all it's fuel (with two Delta-gliders docked, keep in mind). I think it's more of a dV of about 283 km/s. Last edited by Pipcard; 12-25-2011 at 09:30 PM.
 12-25-2011, 10:10 PM #38 dgatsoulis ele2png user @Pipcard The ISP in the case of the ini files you posted above is the exhaust velocity. dv= ln((EmptyMass+Fuelmass)/Emptymass)*exhaustV Without any other payload the James Cook has a dV of 309213,46 m/s (309,21346 km/s) and the Deepstar has 277258,87 m/s (277,25887 km/s)
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 12-25-2011, 10:11 PM #39 Pipcard mikusingularity Size comparison time! The Donovan-class Interplanetary Vehicle (the huge ship in the middle) has a similar dV to the UCGO Arrow, which is about 90 km/s. If we're going to use the Arrow, know that it only has one docking port. Or maybe we should use the Deepstar. The Donovan is too big. I wish I could develop my own interplanetary spacecraft, but I don't think I have enough time (so I won't even attempt it). I still haven't learned how to develop vessels. Also, the is overkill. It has no problem with two XR5s docked to it! Last edited by Pipcard; 12-25-2011 at 10:34 PM.
 12-25-2011, 11:04 PM #40 garyw O-F Administrator Quote: Originally Posted by dgatsoulis  Without any other payload the James Cook has a dV of 309213,46 m/s (309,21346 km/s) and the Deepstar has 277258,87 m/s (277,25887 km/s) I didn't want to use the deepstar because it had too much dV. I didn't realise the James Cook had even more. With that you really could take a holiday to the oort cloud. Oh well. ---------- Post added at 23:02 ---------- Previous post was at 23:01 ---------- Quote: Originally Posted by Arrowstar  Hey Gary, I need to know what kind of trajectories you want for the Mars missions. Should we do direct for the unmanned stuff and the free return for the manned mission(s)? hmmm, good question. Direct for unmanned, yes. Do we need free return for manned? We'll be taking a couple of XR2's so is a direct abort an option? ---------- Post added at 23:04 ---------- Previous post was at 23:02 ---------- Quote: Originally Posted by Pipcard  The Donovan-class Interplanetary Vehicle (the huge ship in the middle) has a similar dV to the UCGO Arrow, which is about 90 km/s. If we're going to use the Arrow, know that it only has one docking port. Or maybe we should use the Deepstar. The Donovan is too big. We aren't. The James Cook was requested by the people participating so that's what is now going to be used. Quote: Originally Posted by Pipcard  I wish I could develop my own interplanetary spacecraft, but I don't think I have enough time (so I won't even attempt it). I still haven't learned how to develop vessels. Doesn't matter. It's the James Cook now. Quote: Originally Posted by Pipcard  Also, the Long Shot is overkill. It has no problem with two XR5s docked to it! So is the deepstar and james cook in my opinion thats why I wanted the Cosmos - 60km/s of dV.
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 12-25-2011, 11:32 PM #41 dgatsoulis ele2png user I don't think that there is a need to change the James Cook just because of the dv it can have when it's fully loaded with fuel, 2400 tons of it. According to the mission roster, there are 6 missions that dock with the Cook for supplies: One XR5 (OFMM 5), two DGIVs (OFMM 11 and 18), one ShuttleC (OFMM 12) and two XR2s (OFMM 21 and 22). Even if the payloads of the ships in these missions consisted entirely of fuel for the James Cook, it cannot have more than 467 tons of fuel, giving it a total dv of 127 km/s. If the only refueling mission is the XR5 and you calculate a factor of 0.85 for the dead weight of the containers then you get 367.2 tons of fuel, giving a dv of 107,6 km/s, which is close to what the Arrow has.
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 12-25-2011, 11:38 PM #42 garyw O-F Administrator Good points dgatsoulis. I was thinking of having the mars ship in orbit with 5-10% of fuel load anyway just for orbtial reboosts. That would be added to whatever is sent up in a couple of resupply missions - of course we also need to add other supplies for the crew so not every flight will be a fuel supply flight.
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12-26-2011, 04:51 AM   #43
Arrowstar
Probenaut

So we'll start with an empty Cook? That sounds like a plan. Don't screw up the fuel resupply missions!

---------- Post added at 11:37 PM ---------- Previous post was at 08:45 PM ----------

Quote:
Originally Posted by dgatsoulis
If the only refueling mission is the XR5 and you calculate a factor of 0.85 for the dead weight of the containers then you get 367.2 tons of fuel, giving a dv of 107,6 km/s, which is close to what the Arrow has.
That's still quite a bit. Even only loaded with that much fuel, there's almost no reason to optimize the Earth-Mars trajectory, as it can pretty much hit whatever target it wants, whenever it wants. If we want to make this more interesting, I might suggest limiting the fuel loads on the supply flights, maybe try to keep the available dV under 10 km/s or something.

Just a thought.

---------- Post added at 11:51 PM ---------- Previous post was at 11:37 PM ----------

Alright, looking at the departure numbers, if we want to do a Christmas departure in 2017 to send the Cook to Mars, here's my recommendation on parking orbit for the Cook:

 SMA [km] Ecc Inc [deg] RAAN [deg] Arg. of Peri. [deg] 6678 (300 km agl) 0 28.5 135 0

Keeping the Cook at a RAAN of about 135 degrees is important. I selected the inclination of 28.5 degrees because I believe that should be accessible from KSC, WIN, etc.

If we depart from this orbit, we're looking at about 3.5 km/sec of dV to place the Cook on a free return trajectory to Mars.

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 12-26-2011, 06:07 AM #44 Napalm42 Drell Admiral, Citadel Fleet Sounds perfectly reasonable, even with only 90 km/s, 3.5 would basically guarantee you'd have fuel to do some sort of ghastly muck up and still have plenty to come home with.
 12-26-2011, 06:54 AM #45 Arrowstar Probenaut "Only" 90 km/s?
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