[RSS/RO/RP-1] Trying to do the first solar-powered satellite contract but my satellite's solar panels aren't pointing at the sun and I don't know how to get my periapsis to above 300 km with the devbranch version of mechjeb pvg

[GoatQueerLovesChocolate]

I'm trying to get my first solar powered, but I'm having an hard time getting my craft to above 300 km periapsis with the devbranch version of mechjeb pvg. I tried instead doing a parking orbit which did work but I want to be able to automate the launch to above 300 km periapsis. Then there's also the problem of my rocket being unable to point its solar panels at the sun after I burn the vacuum-optimized solid rocket kickstage, Idk how to fix that. the satellite is an unguided stage. Also there's the problem of the satellite being unable to last for the 14 days necessary to complete the First Solar powered Satellite contract and I know that I need to have my solar panels be more exposed to the sun to fix that but I don't know how to do that since the unguided stage will not be able to point at the sun on its own. I am doing the Early Light Satellite program

Edit 1: Gonna try to see if decoupling the satellite from the GCRC works for getting solar power. Also lowered the amount of GCRC kickstage fuel

Edit 2(Issue resolved): Decoupling the Satellite from the GCRC and increasing the lenght of the solar panels worked quite nicely, I was able to get enough power from the solar panels, only problem now is that going to high warp to wait is hurting my eyes due to how disorienting it is

Edited February 24 by GoatQueerLovesChocolate
The problem has been resolved

[DennisB]

If you have no control over your satellite, the only solution is to adjust the launch time to have a good orientation, when reaching orbit.

[GoatQueerLovesChocolate]

1 hour ago, DennisB said:

If you have no control over your satellite, the only solution is to adjust the launch time to have a good orientation, when reaching orbit.

 I don't know how to do that to be honest. What are some ways to do it exactly? Would launching into a polar orbit help? @DennisB

[DennisB]

If you know, where the Sun was at launch and by which angle your solar panels were off from the ideal position, when reaching equatorial orbit, you can calculate how many hours earlier or later in the day you have to launch to get into the right position. The Earth rotates with 15 degrees per hour. Launching into a polar orbit would be fine too, if you launch at sunrise or sunset. 

[GoatQueerLovesChocolate]

13 minutes ago, DennisB said:

If you know, where the Sun was at launch and by which angle your solar panels were off from the ideal position, when reaching equatorial orbit, you can calculate how many hours earlier or later in the day you have to launch to get into the right position. The Earth rotates with 15 degrees per hour. Launching into a polar orbit would be fine too, if you launch at sunrise or sunset. 

I'm actually pretty bad at math. And I don't really know where the sun is at launch. I only know they aren't exposed enough to the sun because kerbalism says only 8% of the solar panels are exposed to the sun.
Also, would igniting the unguided vacuum-optimized solid rocket kickstage very close to apoapsis be something that mechjeb PVG devbranch version can do or do I require to like learn how to use kOS?

[GoatQueerLovesChocolate]

The rocket seems to require too much delta-v in order to get to orbit with just the LR-79(S3D config) and the Agena stage in order to get into something polar-like like a sun-synchronous orbit

[jimmymcgoochie]

A few hints for you:

1. Put a single large solar panel on the top of your satellite, or rotate the four you have to be angled forwards. Only one panel will get sunlight at a time in your current design, but if they all face the same way then you can get much more power.
2. When launching to a periapsis insertion (which is the default), your apoapsis will be on the opposite side of the Earth to your launchsite. Since you’ll need to burn prograde there to boost your orbit, if you launch just as the sun is setting and go east, you’ll be pointing roughly towards the sun when you reach your apoapsis and your solar panels will be facing the sun if you put them on the top. For a polar orbit it’s a bit harder, but you could try putting a single large solar panel on the top, facing to one side and positioned to prevent torque on the unguided stage, and then launch north or south at sunrise or sunset; use roll control to point the solar panel at the sun before doing the final boost burn, however this means you won’t get any spin stabilisation.
3. I don’t remember the specific orbital requirements for this contract. Do you need such a high apoapsis?
4. There will always be some element of manual input required, especially with unguided stages, however you can use PVG to launch to the parking orbit and then use maneuver planner to do the rest in a mostly automated manner.
5. Your delta-V doesn’t seem that far off considering you’re launching to a high inclination orbit with a relatively short burning rocket and a relatively low TWR off the pad. You might be able to launch to that parking orbit with a much lighter probe and/or kick stage.

[GoatQueerLovesChocolate]

21 hours ago, jimmymcgoochie said:

A few hints for you:

1. Put a single large solar panel on the top of your satellite, or rotate the four you have to be angled forwards. Only one panel will get sunlight at a time in your current design, but if they all face the same way then you can get much more power.
2. When launching to a periapsis insertion (which is the default), your apoapsis will be on the opposite side of the Earth to your launchsite. Since you’ll need to burn prograde there to boost your orbit, if you launch just as the sun is setting and go east, you’ll be pointing roughly towards the sun when you reach your apoapsis and your solar panels will be facing the sun if you put them on the top. For a polar orbit it’s a bit harder, but you could try putting a single large solar panel on the top, facing to one side and positioned to prevent torque on the unguided stage, and then launch north or south at sunrise or sunset; use roll control to point the solar panel at the sun before doing the final boost burn, however this means you won’t get any spin stabilisation.
3. I don’t remember the specific orbital requirements for this contract. Do you need such a high apoapsis?
4. There will always be some element of manual input required, especially with unguided stages, however you can use PVG to launch to the parking orbit and then use maneuver planner to do the rest in a mostly automated manner.
5. Your delta-V doesn’t seem that far off considering you’re launching to a high inclination orbit with a relatively short burning rocket and a relatively low TWR off the pad. You might be able to launch to that parking orbit with a much lighter probe and/or kick stage.

Well the parameters for the first solar powered satellite are just it being at above 300 km and to have like 100+ units of electricity for 14 days. I am also using the GCRC as my solid rocket kickstage so that make it kinda hard to control and the GCRC was the lightest kickstage I could find since the aerobee kickstage is 455 kg while the GCRC removes around 200 something kg from the unguided kickstage

[GoatQueerLovesChocolate]

21 hours ago, jimmymcgoochie said:

Put a single large solar panel on the top of your satellite, or rotate the four you have to be angled forwards. Only one panel will get sunlight at a time in your current design, but if they all face the same way then you can get much more power

Wouldn't I have to point them backward like this since the GCRC covers the solar panels so that they don't get sunlight?

[GoatQueerLovesChocolate]

I thank everybody for their help. Increasing the solar panel lenght definitely helped. And detaching the satellite from the GCRC also helped a lot in getting them more sun exposure

[GoatQueerLovesChocolate]

@jimmymcgoochie By the way what's a good TWR for an early game launch vehicle? I just unlocked the Castor 1 and I don't know how many to add

[jimmymcgoochie]

I don’t think you need a GCRC kick stage, a few separation/spin motors would probably do the job if all you’re aiming for is a 300km periapsis.

Re. TWR, anything from 1.2 to 1.8 is pretty reasonable- any lower and you’ll lose a lot of delta-V just fighting gravity, any higher and atmospheric drag will do the same. Two Castor 1s would probably be enough.

[GoatQueerLovesChocolate]

22 hours ago, jimmymcgoochie said:

I don’t think you need a GCRC kick stage, a few separation/spin motors would probably do the job if all you’re aiming for is a 300km periapsis.

Re. TWR, anything from 1.2 to 1.8 is pretty reasonable- any lower and you’ll lose a lot of delta-V just fighting gravity, any higher and atmospheric drag will do the same. Two Castor 1s would probably be enough.

Understood. By the way When I add the Castor 1, for some reason mechjeb wont stage the launch clamp when the rocket has two Castor 1 and the LR79 engine in the same stage nor when the Castor 1 are in a separate stage above the LR79 and I don't know why

[jimmymcgoochie]

Put the Castors in the same stage as the launch clamps so they ignite when the clamps release.