Flight Question Designing flight plans for rockets

[icedown]

I'm looking at using the Quasar to put the initial parts of my next station in orbit. I used the Delta 4 heavy for my last one but I'm looking at lifting 2 parts at once this time. How do you guys build a flight plan for these vessels?

 

[Urwumpe]

I'm looking at using the Quasar to put the initial parts of my next station in orbit. I used the Delta 4 heavy for my last one but I'm looking at lifting 2 parts at once this time. How do you guys build a flight plan for these vessels?

What do you mean with "flight plan"? A flight plan for a mission, and in logical consequence a mission? Or simply a scenario for the launch?

 

[PhantomCruiser]

Let me see if I understand your question... You are wanting to use the Quasar to lift 2 station modules/parts during a single launch?

If that's the case I don't think it'd be too much of a problem. You'd need to edit the .ini file to add the extra payload (multistage allows for it, see the documentation).

That is if the Quasar is still multistage based. My computer crapped out on me and I haven't gotten Orbiter to work inside Linux yet. But I'm pretty sure it can be done (multiple payloads on Quasar that is).

 

[garyw]

That is if the Quasar is still multistage based.

I'm fairly certain it is. I've not used Quasar yet but I have used both Jarvis and Neptune. One nice thing about mutlistage is that it helps make rockets very configurable.

 

[icedown]

Sorry bout that, I shouldn't have posted that time of the morning. Most of my remaining brain power at that point was focused on keeping my head from bouncing off the keyboard. :zzz:

I guess this is more of a poll than a howto question. When your launching those, the pitch program is pretty much a given but once it's complete how do you design the remaining part of the multistage guidance? Do fly it manually and do trial and error to get the settings you need? Or do you have program or spread sheet to help you calculate it? or break out the slide rule and a couple of cups of coffee?

And one question about the Quasar, Does the upper stage not have RCS or am I doing something wrong?

 

[asbjos]

I fly my rockets manually 99 % of the time with one hand on my keyboard, even when I'm going for a rendezvous and need a correct inclination. That's what I love with Orbiter: pretending to be a real astronauts. In fact, all of the Apollo commanders who did a landing, landed on the Moon manually, even though they had an autopilot.

If the rocket is very heavy and has a slow climb rate, I will experience that under the launch, and adjust my ascent after that.

On your second question I can't answer: I don't have any experience with that add-on

 

[PhantomCruiser]

OK, gotcha... When I'm tweaking a guidance file I'll typically get my kid in the room with me to take some quick notes. I'll launch manually and every 10 seconds call out my pitch angle and altitude. What I try to aim for is a 40 degree angle at 20,000, 30 degrees at 30,000 and 20 degrees at 40K. Then I ride out 20 degrees while watching vertical acceleration in the SurfaceMFD. and keeping an eye out for ApA and PeA on the OrbitMFD.

If I can hit my target apogee with a reasonably circular orbit, I'll take the data that my kid collected for me and write the guidance file. This file will be my "baseline" and I'll tweak it over and over (and over and over, etc...) until I get what I want, or get it "close enough". After all I'm an electronics technician not a rocket scientist...

 

[C3PO]

When your launching those, the pitch program is pretty much a given but once it's complete how do you design the remaining part of the multistage guidance? Do fly it manually and do trial and error to get the settings you need? Or do you have program or spread sheet to help you calculate it? or break out the slide rule and a couple of cups of coffee?

It all depends on what you're trying to achieve. If you're launching the first module, the only thing you need to decide is inclination and altitude. It sounds like you're using the last stage of the launcher to get into the final orbit. In that case you can fly the last portion manually.

The way I usually do this is to tweak the launch program to shut the engine(s) when ApA equals the final altitude, and the pitch profile to get the highest PeA possible. You can also shut down the engines manually. Then it's just a matter of raising the PeA to the correct altitude.

Trial and error can be time consuming, but usually a good way to learn. especially if you can get tips from people with more experience.

 

[icedown]

I'm all to familiar with the trial and error method. I was just hoping someone had an easier way. If I can ever get these PEG calculations figured out I'm going to try to write a configurable mfd that's a compliment to the LaunchMFD which I use every launch. Let LaunchMFD control the yaw and mine control the pitch.

 

[PhantomCruiser]

Artlav's UAP isn't too bad. It's pretty slow to start the gravity turn sometimes (depends on the weight of the rocket I think). But it'll get me to orbit (and circular) nearly every time.

 

[icedown]

I wandered out to the pad to check on how cargo loading was going. I get there and :facepalm:

I realize that the Quasar 471 might be a little overkill for just 2 SSBB modules.

Thanks for the UAP suggestion, I've finally got it flying right to target now.