Entry tags:
ComSat/ScanSat Fleet to Jool
The Alarm Clock mod has a Jool launch window for Year 1, Day 199. Actually, I think it’s actually Day 200 because the mod gives you a day’s warning by default. But since Jool has such a big gravity well, it’s a big target and a large window of opportunity, roughly 25 days, so I could send an entire fleet of craft.
Which is what I intend to so.
The KSP delta-V Map has the following information for Jool:
Jool (930 ejection + 980 transfer + 160 capture) + 20% = 2,484 m/s
Pol 2,484 + (160 capture + 810 orbit) + 20% = 3,648 m/s
Bop 2,484 + (220 capture + 890 orbit) + 20% = 3,816 m/s
Tylo 2,484 + (400 capture + 1,050 orbit) + 20% = 4,224 m/s
Val 2,484 + (620 capture + 850 orbit) + 20% = 3,540 m/s
Laythe 2,484 + (930 capture + 890 orbit) + 20% = 4,668 m/s
Laythe is the most intensive delta-V target in the Jool system so if I build a craft that will get there, an identical craft will get to any of the other moons. I just launched a similar craft to Moho with over 6,000 m/s of dV so I could just duplicate that and launch it.
Not just a duplicate, though. Because Jool is so far out, the sun is dimmer and so I would need more solar panels.
The Orbital Survey requires two different antennas to map. The Communotron DTS-M1 will perform the Region mapping at a cost of 2 ec/s while the RA-15 will do Visual mapping for a cost of only 1 ec/s. The plan is to run only one scan at a time so the maximun is 2 ec/s. The HECS2 probe core requires 0.025 ec/s so I will need 2.025 ec/s to run the satellite and scan.
In Kerbin orbit, a single OX-10C round solar panel would be enough but out at Jool, the sun is only about 4% as bright. To run the satellite and scan I will need 15 panel arrays!
So, I started slapping solar panels on the craft I had sent to Moho and there was just barely enough space to have 8 panels on each side.
Mission Designation : SCAN-5
Rocket Model : EchoStar J-I
Total delta-V (to orbit) : 10,031 m/s (6,258 m/s)
Surface TWR : 1.383
Total Mass (to orbit) : 382.93 t (75.56 t)
Dry Mass : 68.21 t
Part Count : 89
Height : 32.28 m
Width : 7.99 t
Length : 8.02 t
Mission Objectives : Orbit and scan Joolian moons
Given the large transfer window, I will launch the first on day 189, then the next 5 days later, and so on, spacing them out so that, when they arrive, I don’t have a bunch or insertion burns all happening at once.
The launch goes well up until the point of having to make the circularization burn into orbit at apoapsis where, like the launch to Moho, the trajectory line fails to appear. I just use the Time to Apoapsis to estimate and get into orbit. Remembering the problems I had last time, I go straight to saving, closing KSP2, and rebooting. When I return, the craft is on a reentry trajectory and the path is still not showing.
I use “F8” to get into the cheat menu and use that to set my orbit, at which point the trajectory line appears.
I think I know why this is happening. When I originally designed the rocket, I had two probe cores. One was going to be for the Visual orbital survey and the other for the Region survey. I realized that I could split the orbital altitude difference and do both with a single satellite and removed the upper probe core. I believe that KSP2 still thinks that probe core is there in some way because when I switch back from the craft to, say, the KSC, I get a popup message that the craft is no longer controlled and is on a crash trajectory. I think at that moment it is treating the craft like debris. For the next launch I will rebuild the probe portion of the craft from scratch so that hopefully it will not forget.
The Jool transfer Window is 96.6 degrees and the Ejection Angle is -114.4 degrees. The Alarm Clock mod has taken care of the timing of the Transfer Window so all I need to do is transfer from Kerbin orbit at the correct Ejection Angle. And, again, because Jool’s gravity well is so large, there is a lot of leeway. I could eyeball it but I use a protractor on the screen anyway.
With a 2,576 m/s burn lasting 10 minutes 20 seconds I get a Jool intercept way to the south on Jool’s sphere of influence. I can adjust it left and right a little but, ejecting from Kerbin orbit, I cannot very much change the vertical alignment to get an insertion into an equatorial orbit without spending tons of delta-V. This I will fix with a mid-course correction.
That mid-course correction will be on Year 1, Day 270 and will be only about 205 m/s to get a good equatorial flyby. After that, the insertion burn will choose the best moon to try to orbit.
Next, to fix my rocket and do this again. And again. And then again.
Which is what I intend to so.
The KSP delta-V Map has the following information for Jool:
Jool (930 ejection + 980 transfer + 160 capture) + 20% = 2,484 m/s
Pol 2,484 + (160 capture + 810 orbit) + 20% = 3,648 m/s
Bop 2,484 + (220 capture + 890 orbit) + 20% = 3,816 m/s
Tylo 2,484 + (400 capture + 1,050 orbit) + 20% = 4,224 m/s
Val 2,484 + (620 capture + 850 orbit) + 20% = 3,540 m/s
Laythe 2,484 + (930 capture + 890 orbit) + 20% = 4,668 m/s
Laythe is the most intensive delta-V target in the Jool system so if I build a craft that will get there, an identical craft will get to any of the other moons. I just launched a similar craft to Moho with over 6,000 m/s of dV so I could just duplicate that and launch it.
Not just a duplicate, though. Because Jool is so far out, the sun is dimmer and so I would need more solar panels.
The Orbital Survey requires two different antennas to map. The Communotron DTS-M1 will perform the Region mapping at a cost of 2 ec/s while the RA-15 will do Visual mapping for a cost of only 1 ec/s. The plan is to run only one scan at a time so the maximun is 2 ec/s. The HECS2 probe core requires 0.025 ec/s so I will need 2.025 ec/s to run the satellite and scan.
In Kerbin orbit, a single OX-10C round solar panel would be enough but out at Jool, the sun is only about 4% as bright. To run the satellite and scan I will need 15 panel arrays!
So, I started slapping solar panels on the craft I had sent to Moho and there was just barely enough space to have 8 panels on each side.
Mission Designation : SCAN-5
Rocket Model : EchoStar J-I
Total delta-V (to orbit) : 10,031 m/s (6,258 m/s)
Surface TWR : 1.383
Total Mass (to orbit) : 382.93 t (75.56 t)
Dry Mass : 68.21 t
Part Count : 89
Height : 32.28 m
Width : 7.99 t
Length : 8.02 t
Mission Objectives : Orbit and scan Joolian moons
Given the large transfer window, I will launch the first on day 189, then the next 5 days later, and so on, spacing them out so that, when they arrive, I don’t have a bunch or insertion burns all happening at once.
The launch goes well up until the point of having to make the circularization burn into orbit at apoapsis where, like the launch to Moho, the trajectory line fails to appear. I just use the Time to Apoapsis to estimate and get into orbit. Remembering the problems I had last time, I go straight to saving, closing KSP2, and rebooting. When I return, the craft is on a reentry trajectory and the path is still not showing.
I use “F8” to get into the cheat menu and use that to set my orbit, at which point the trajectory line appears.
I think I know why this is happening. When I originally designed the rocket, I had two probe cores. One was going to be for the Visual orbital survey and the other for the Region survey. I realized that I could split the orbital altitude difference and do both with a single satellite and removed the upper probe core. I believe that KSP2 still thinks that probe core is there in some way because when I switch back from the craft to, say, the KSC, I get a popup message that the craft is no longer controlled and is on a crash trajectory. I think at that moment it is treating the craft like debris. For the next launch I will rebuild the probe portion of the craft from scratch so that hopefully it will not forget.
The Jool transfer Window is 96.6 degrees and the Ejection Angle is -114.4 degrees. The Alarm Clock mod has taken care of the timing of the Transfer Window so all I need to do is transfer from Kerbin orbit at the correct Ejection Angle. And, again, because Jool’s gravity well is so large, there is a lot of leeway. I could eyeball it but I use a protractor on the screen anyway.
With a 2,576 m/s burn lasting 10 minutes 20 seconds I get a Jool intercept way to the south on Jool’s sphere of influence. I can adjust it left and right a little but, ejecting from Kerbin orbit, I cannot very much change the vertical alignment to get an insertion into an equatorial orbit without spending tons of delta-V. This I will fix with a mid-course correction.
That mid-course correction will be on Year 1, Day 270 and will be only about 205 m/s to get a good equatorial flyby. After that, the insertion burn will choose the best moon to try to orbit.
Next, to fix my rocket and do this again. And again. And then again.