Rendezvous

[paul_c]

Oh cool, I thought it did it. Docking too? And other fun stuff like Mun landings?

[Anonymous49]

Just now, paul_c said:

Oh cool, I thought it did it. Docking too? And other fun stuff like Mun landings?

i terminated my mun base because it broke up

[paul_c]

I've never had much luck building a surface base on the Mun - its just never flat, where you want it. Minmus is a different matter, the ice lakes are probably purpose-designed for people who don't like slopes. Or is this an orbital Mun base?

[Anonymous49]

2 minutes ago, paul_c said:

I've never had much luck building a surface base on the Mun - its just never flat, where you want it. Minmus is a different matter, the ice lakes are probably purpose-designed for people who don't like slopes. Or is this an orbital Mun base?

a landing mun base

[paul_c]

Ok cool don't forget to at least try a bit of docking (in space). Its a good achievement once you have sussed it. I tried and failed a number of times before it "clicked" for me, now I love it.

Docking on the surface is a different kettle of fish really.

[Anonymous49]

17 minutes ago, paul_c said:

Ok cool don't forget to at least try a bit of docking (in space). Its a good achievement once you have sussed it. I tried and failed a number of times before it "clicked" for me, now I love it.

Docking on the surface is a different kettle of fish really.

i know i am rebuilding the station

[Anonymous49]

I sent the new station via a SSTO (which apparently uses the reusuable Explorer Booster 2). It placed it in a intended orbit and it's coming back down

[Anonymous49]

guys i have a achievement and a super bad news. I FINALLY DOCKED A CAPSULE WITH THE STATION!!! but unfortunately that thing kept swinging around and Bob had to EVA to complete his mission. The docking caused the perigee to lower to 50km and for Bob, -200km. Bob unfortunately had to die while as with the help of some cheats, finally got back into orbit. I had to sacrifice my expensive boosters which are reusuable (but luckily the launch abort tower was already ditched before the docking so it came back alive).

Update:  Bob came back when I changed my state in the sfs from dead to avaliable

i mean bill

[paul_c]

Given the edge of the atmosphere is 70km, If you're doing a rendezvous/docking in LKO then it makes sense to have the station a bit above 70, so you can dip below it to catch it up (orbital mechanics). The nearer things are to 70, the more the additional consideration of not dropping into the atmosphere is!

For a beginner, I'd recommend the station to be about 85-90 minimum, so its a non-issue. 

And, to fully understand and be very deliberate and procedural with all the steps, so that you are in control at all times!

[Anonymous49]

1 hour ago, paul_c said:

Given the edge of the atmosphere is 70km, If you're doing a rendezvous/docking in LKO then it makes sense to have the station a bit above 70, so you can dip below it to catch it up (orbital mechanics). The nearer things are to 70, the more the additional consideration of not dropping into the atmosphere is!

For a beginner, I'd recommend the station to be about 85-90 minimum, so its a non-issue. 

And, to fully understand and be very deliberate and procedural with all the steps, so that you are in control at all times!

it's in 80

[paul_c]

So your range of available altitude, if your docking craft is behind and needs to "catch up", is 70-80km. You shouldn't need to go 50km Pe at any point. 

The similarity of the orbit; and the similarity of the speeds of the craft, are intimately linked. You can approach a station at 80x80 using a 79.9x80 orbit if you want....it will take a while, but it will be at a very controllable speed.

[Anonymous49]

57 minutes ago, paul_c said:

So your range of available altitude, if your docking craft is behind and needs to "catch up", is 70-80km. You shouldn't need to go 50km Pe at any point. 

The similarity of the orbit; and the similarity of the speeds of the craft, are intimately linked. You can approach a station at 80x80 using a 79.9x80 orbit if you want....it will take a while, but it will be at a very controllable speed.

i accidentally retroed myself i mean

so i can dock

[paul_c]

Yeah, that's the way the Pe ends up at 50km!!!

Ok it was an accident but at no point should you be out of control of the situation, or in any danger of dropping out of the sky. What if the spaceships that dock to the ISS in real life ended up with both station and craft in a fiery explosion? This is why its worth taking the time to understand the process of what an orbital rendezvous is, and how to dock. KSP makes it easy, much easier than real life - what with the KSC being on the equator, no atmosphere at all above 70km, etc. But still, rendezvous/docking is one of those things where if you follow a "cookbook" rather than random pointing and squirting with a big rocket, it will all fall into place (no pun intended).

Or did MechJob burn retro and put it into de-orbit?

[Anonymous49]

11 hours ago, paul_c said:

Yeah, that's the way the Pe ends up at 50km!!!

Ok it was an accident but at no point should you be out of control of the situation, or in any danger of dropping out of the sky. What if the spaceships that dock to the ISS in real life ended up with both station and craft in a fiery explosion? This is why its worth taking the time to understand the process of what an orbital rendezvous is, and how to dock. KSP makes it easy, much easier than real life - what with the KSC being on the equator, no atmosphere at all above 70km, etc. But still, rendezvous/docking is one of those things where if you follow a "cookbook" rather than random pointing and squirting with a big rocket, it will all fall into place (no pun intended).

Or did MechJob burn retro and put it into de-orbit?

the docking port is actually facing retro

just having a bit of trouble reaching orbit with the second module

the second module is too freaking big

and heavy

with the super large fairing and the decoupler installed, it will be 44 tonnes and the radial size of 2.5m. Need a rocket for that, and don't forget to not go pass to level 5 things. (I mean I do have level 6 but are just solar panels and precision engineering which TOTALLY doesn't help in building rockets

[paul_c]

A retro facing docking port is no harder than a forwards one - the icons for targetting and docking appear in the navball for both pointing to/from; and velocity to/from. 

Trouble reaching orbit....what kind of trouble? What's the delta V of the whole thing? Or is it some other kind of flyability issue?

[Anonymous49]

6 minutes ago, paul_c said:

A retro facing docking port is no harder than a forwards one - the icons for targetting and docking appear in the navball for both pointing to/from; and velocity to/from. 

Trouble reaching orbit....what kind of trouble? What's the delta V of the whole thing? Or is it some other kind of flyability issue?

a ton of delta v, but will deorbit when my boosters go out

[paul_c]

Makes no sense whatsoever! If something is in orbit, it stays in orbit (unless its Pe is less the 70km etc). Things don't deorbit when boosters go out,

[Anonymous49]

1 minute ago, paul_c said:

Makes no sense whatsoever! If something is in orbit, it stays in orbit (unless its Pe is less the 70km etc). Things don't deorbit when boosters go out,

the boosters jettsion when ap is ~20km

[paul_c]

What is the delta v of the whole thing?

[Anonymous49]

and the time to Apogee slowly decreases until I fall back down to KERBIN

Just now, paul_c said:

What is the delta v of the whole thing?

starts of with around 4.4km but will increase due to asparagus staging

it would reach around 7km in flight

[paul_c]

Ok a few basics:

1. "The boosters jettison when the Ap is 20km" - in itself not terribly useful. Its an indication of what the 1st stage does, but we need info on the other stages too.

2. The units of delta V are m/s. Its a change of velocity/speed. km is a distance measurement.

3. Staging, be it conventional, onion, asparagus, whatever, does not alter the overall delta V because that is a fixed thing, relating to the rocket design and the amount of fuel in it. If its using normal decouplers for its staging, the KSP VAB editor will make a pretty good go at calculating the delta V properly.

If what you're saying is the overall deltaV is 4400m/s, and it cannot reach orbit, something else is wrong. For example, is the staging correct? You're not decoupling full fuel tanks, or not activating engines etc? Maybe one or some of the engines aren't powerful enough (too low TWR) and it can't overcome the gravity etc. Maybe you've used an engine optimised for vacuum; or the vacuum values, in a stage which needs to operate in atmosphere.

[Anonymous49]

i'll need a rocket for that

[paul_c]

If I were going to space, I'd need a rocket too.......

[Anonymous49]

2 minutes ago, paul_c said:

Ok a few basics:

1. "The boosters jettison when the Ap is 20km" - in itself not terribly useful. Its an indication of what the 1st stage does, but we need info on the other stages too.

2. The units of delta V are m/s. Its a change of velocity/speed. km is a distance measurement.

3. Staging, be it conventional, onion, asparagus, whatever, does not alter the overall delta V because that is a fixed thing, relating to the rocket design and the amount of fuel in it. If its using normal decouplers for its staging, the KSP VAB editor will make a pretty good go at calculating the delta V properly.

If what you're saying is the overall deltaV is 4400m/s, and it cannot reach orbit, something else is wrong. For example, is the staging correct? You're not decoupling full fuel tanks, or not activating engines etc? Maybe one or some of the engines aren't powerful enough (too low TWR) and it can't overcome the gravity etc. Maybe you've used an engine optimised for vacuum; or the vacuum values, in a stage which needs to operate in atmosphere.

its twr problem

[paul_c]

So you need either a bigger engine, or more engines!