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Orbit the planet?


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I'd be happy knowing what the pink crosshairs do. ;D

(Green circle = current vector, yes?)

PS: Ijuin! Hail and well met! :D

Yes, green bit is your current vector. Purple bit is vector to the launch pad.

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Hello!

I'm pretty sure this has already been suggested, but I'd really acknowledge a means of orbital manoeuvring. A small engine that could be activated and deactivated several times. You know, like the Apollo or Soyuz service module.

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Hello!

I'm pretty sure this has already been suggested, but I'd really acknowledge a means of orbital manoeuvring. A small engine that could be activated and deactivated several times. You know, like the Apollo or Soyuz service module.

What you need to do is get a liquid engine with at least 3-5 tanks of fuel (The more the better) up out of the atmosphere. How you do this is your choice. Shift+Ctrl controls the throttle.

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Too high, too fast.

2400m/s is already too fast.

https://gist.github.com/1075144

...is a table that is your friend.

...and note that this is the speed you want to be heading 'sideways', with the green icon thingy at the horizon line between blue and brown.

Green thingy above the horizon = you are heading upwards (and after half an orbit, you will be heading downwards, with your fate depending on how far down you dip on the return)

Green thingy below the horizon = you are heading doooooooooown and in general that would be bad

Air resistance becomes relevant around 35000m up, so always orbit above that. 40-50km is a good 'safe' zone and gets you around the planet faster than if you went up higher.

Edit: and in case you want to come down, you need a tank of fuel and a liquid engine still attached so you can fire a deorbit burn. Fuel needed is very minimal - say you are orbiting around at 2350m/s at 45km. Dropping that to just 2200m/s will get you down. Brake to 2000m/s and you get down surprisingly fast. The margins are small. As soon as you hit 34-35km, air resistance will hit you like a brick wall, your little pilots get some Gs and you slow down any sideways movement FAST (falling down rapidly from there on)

(Shift/CTRL control your final stage engine. Turn it off when speed and heading is good, flip craft around and point it towards the X-shaped green circle thingy and fire away for brakes...)

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http://dl.dropbox.com/u/22571912/Sunrise%20over%20Kerbal.jpg

A beautiful sunrise as seen from space.

... I'm pretty sure this orbit is stable. Kinda hard to tell with such primitive instrumentation. >_>

(after looking back, it is! 122x80km orbit. Not too shabby.)

edited: Had to fix the orbit numbers. =p I'll be so glad to get an MFD that tells us where we are in an orbit.

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I just got the most perfectest flight ever :D

Took off heading vertically with my three stage, fairly simple 'Torchship 3' rocket. At about 35km I pitched east just below the horizon to burn off the vertical speed and get the required vertical speed. After a couple of adjustments I was in a very, very stable circular orbit at ~40.5km, with one stage and ~3% fuel left. Did a couple of tiny burns to keep horizontal speed perfect and vertical speed <1m/s. ;D

The best part, though, was starting the deorbital burn when KSC was 20° below the horizon. I then squeezed off the last couple drops of to try and nudge myself just a bit father north towards the space center, and, well...

perfectorbit2.png

Yes, that is after a full orbit!

I don't think I could ever do better.

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I just got the most perfectest flight ever :D

Took off heading vertically with my three stage, fairly simple 'Torchship 3' rocket. At about 35km I pitched east just below the horizon to burn off the vertical speed and get the required vertical speed. After a couple of adjustments I was in a very, very stable circular orbit at ~40.5km, with one stage and ~3% fuel left. Did a couple of tiny burns to keep horizontal speed perfect and vertical speed <1m/s. ;D

The best part, though, was starting the deorbital burn when KSC was 20° below the horizon. I then squeezed off the last couple drops of to try and nudge myself just a bit father north towards the space center, and, well...

*snip*

I don't think I could ever do better.

Nice landing! Looks like they'll be home in time for lunch after a five-minute walk.

As for 'doing better,' you could certainly get into orbit with more fuel to maneuver. :P Though I guess part of the fun sometimes lies in making every last drop count!

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I've done a couple of landings in sight of KSC after 1-3 orbits but that's a lot closer than what I've managed. Main problem being that you are effectively throwing a wild guess as to when to deorbit burn (and for how much).

My Kerbals demand a better set of flight instruments from the KSC management before setting foot into that capsule death trap again! :P

Hmm, in fact there really should be multiple cabin/capsule models with different features - so you could go for a very light spartan 'guys in a tin can with a window' or with a more high-tech setup with such bells & whistles as a flight computer...

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Just finished an orbital mission you guys might enjoy. Stable polar orbit with a starting Apogee of69,792M with a speed of 2274.5, Perigee 51,559M with a speed of 2344 m/s. Left the orbit for 17 Hours 20 minutes, by which point the Perigee and Apogee had shifted up and down, Apogee now in the 70,000M range and Perigee in the 40,000M range. I suspect if left on for a day or two longer it might have reentered the atmosphere, but it is hard to tell.

Random stats:

Total Mission Time: 17:38:23

Highest Altitude Achieved: 71649 (My apogee at one point)

Highest Speed: 2352.6 (Subtract .1 for highest speed over land, heh)

Ground Distance Covered: 146,381,000

Total Distance Traveled: 146,417,600

Most Gee Force Endured: 13.2G

Fun thing about the nametag bug. It appears to be about distance traveled, NOT height from the planet. At the end of my orbit the names where totally off the screen.

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Best I've done is an 11 hour orbit mission, at somewhere around 40 orbits.

Apogee was about 65 km, and Perigee was about 60 km... pretty stable, all in all.

I left it running overnight and came back to find it in perfect condition.

I waited for the KSC to appear on the horizon, then did my de-orbit burn with the half tank of fuel I had left.... Ended up landing less then 2 km away from the launch pad.

All in all, success.

As someone else in this thread mentioned, deceleration at perigee and acceleration at apogee will circularize your orbit. That helped.

Here's a video of a previous one-orbit mission

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Just curious, what is the highest altitude orbit you've ever done?

I'm orbiting at an apogee of 183km and a perigee of about 176km.

It seems like a higher orbit would be easier to achieve. Is that a good guess?

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Just curious, what is the highest altitude orbit you've ever done?

I'm orbiting at an apogee of 183km and a perigee of about 176km.

It seems like a higher orbit would be easier to achieve. Is that a good guess?

High orbits need more delta-v to reach, it's easy to accidentally reach escape velocity, and everything takes a long time. Low orbits take less delta-v/less propellant for a given rocket, but have little margin before you hit atmosphere, and you have both more orbital velocity to gain and less time to gain it/correct for errors.

There's a big margin in the middle where even a rather large error in velocity just puts you in another wildly elliptical orbit, though.

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I have a hard time keeping my speed at 2312 m/s at 60km up. I keep running out of fuel because I have to burn everytime the speed drops below 2312, and it was my understanding that it shouldn't do that, that high up because there isn't any wind resistance.

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I have a hard time keeping my speed at 2312 m/s at 60km up. I keep running out of fuel because I have to burn everytime the speed drops below 2312, and it was my understanding that it shouldn't do that, that high up because there isn't any wind resistance.

Orbits aren't totally circular.

As an object orbits away from another object, the orbit's speed decreases.

Basically you are trading speed for altitude. It will reverse once altitude decreases.

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I just tried again. I reached 60km height and my speed was completely horizontal (indicated by the yellow circle) and I pushed the speed to 2312m/s according tot his:

60 km, Vcirc = 2312.68 m/s, Tcirc = 29.89 min, Vesc = 3270.63 m/s

Right now my height just keeps increasing, at 80km now and my speed has decreased to about 2280. What now? It doesn't look like the height will stop increasing at the rate it's going. Is it poissible to my yellow indicator on the horizontal line can be a little off with a half of a millimeter and I'm actually heading out of orbit?

EDIT: Nevermind. My height stopped at about 110km and started decreasing while my speed started to pick up again. Here's to hoping I did everything correct so I fall and miss the planet now :D

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Is it poissible to my yellow indicator on the horizontal line can be a little off with a half of a millimeter and I'm actually heading out of orbit?

Yeah, the vertical speed indicator is very imprecise. Watch your altimeter, and when it stops changing, then your vertical speed is zero. The VSI is fairly useless for making orbital adjustments, it just tells you when you're getting close to apokee/perikee.

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  • 2 weeks later...

Got myself into orbit (very ecliptical to start), and then using the tips in this thread managed to get it nearly circular - apokee 78.779km, perokee 76.160km.

However, there seems to be a drift upwards of about 200m per orbit. I haven't added any thrust since getting into the stable orbit, so I'm wondering what's causing the drift?

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