A Few Travel Questions

[Guardian Hope]

So, I have a predicament. I have been playing KSP which I have owned for a while and although I only got about 20 hours under my belt since the Early Access days (don't really have time to play games) I have gotten back into it. Well, I inadvertently launched a test orbital ship into space with enough power to break Kerbin orbit and enter into what appears to be a stable elongated orbit of the sun (read it all as it goes down here: 

Anyways, as I plan my rescue and refine my space program abilities (we only just achieved Kerbin orbital capabilities last night!) I realized that to attempt a mission of such magnitude presents a few hiccups. So, I will break my multi-part question down into smaller ones:

Launching from KSC

• My first thought was SSTO but not only can the KSC construction building (fully upgraded) not handle rockets that I'm building (they get to be too tall for the building) but the SSTO component creates so much drag that even with the SpaceY Heavy Lifters SRB all firing at launch, it still takes the Liquid Rockets to reach a high enough altitude and burns through most of the fuel supply meaning no turns to establish orbit. I've seen a lot of craft on here and I'm sitting here asking myself, what am I doing wrong (the thread I linked off to contains the booster segment in my second post). It feels like drag as smaller launches for satellites on a new platform are working well as my space program techniques are refined (I get the Mach effect and have to use SAS to stabilize or else be flipping back to the ground in the SSTO booster so I feel I designed the vessel wrong)

Orbit of Kerbin

• Can I dock a spacecraft at an orbital station for refueling (I do have a number of mods from KIS to KAS and than some - not reflected in the post I linked off to as I didn't have them then)?
• Can I dock multiple components to create a larger spacecraft in orbit of Kerbin?

Planetary Assist Maneuvers

• My space program, as I stated, is obviously at a very early era with it just beginning to create craft capable of orbiting Kerbin. However, I successfully launched an automated craft that reached 11,000+m/sec and was plotted on Kerbin's escape before it was destroyed. What I am trying to figure out (and I have been reading) is how do I make the cross over maneuver to intercept a planet's orbit? (I think I have started to figure out how to do the orbital assists but getting to the planet is a bit harder). I see the alignment come up on my map when I set the target with the time, degrees, and delta-v needed I think. I am just not sure if that's what I am supposed to follow.

Intercepting the target Spacecraft

• When I select a planet as a target, KSP can give me what I believe is the appropriate information if what I said above is true. Now I'm just trying to figure out how to intercept a spacecraft moving 3,000 m/sec and move my Kerbalnauts from the first craft to the rescue craft. Can I just EVA them at a close enough range?

Returning to Kerbin

• KSC has no beacon. No ILS marker. Nothing. How exactly am I supposed to return to KSC in a spacecraft. So far my spacecraft have been pods so it didn't matter where on the planet they landed but I'm constructing a spaceplane for the final descent so landing at KSC which has a runway would be helpful. Knowing this would allow me to calculate a de-orbit trajectory. 
• Reverse Thrusters - we're talking about a multi-stage interplanetary mission. We'll obviously need to slow the spacecraft down before reaching Kerbin descent. Is it even possible to mount reverse thrusters such as SRBs?

Miscellaneous

• I think I am doing something wrong with the radial decouplers. When I try to decouple the SRBs from first stage they don't actually decouple and stay attached. You can see and hear the decouple effects. This is with the stock radial decouplers. Interestingly, in the many, many times my rockets have exploded, you can see in the report that the radial decouplers are colliding with the SRBs but the SRBs aren't exploding (these catastrophic failures where my rockets blew up were on reentry to Kerbin).

Yes, so a number of questions but a very complicated and challenging mission coming up which I hope to learn a lot with.

[Snark]

1 hour ago, Guardian Hope said:

Launching from KSC

• My first thought was SSTO but not only can the KSC construction building (fully upgraded) not handle rockets that I'm building (they get to be too tall for the building) but the SSTO component creates so much drag that even with the SpaceY Heavy Lifters SRB all firing at launch, it still takes the Liquid Rockets to reach a high enough altitude and burns through most of the fuel supply meaning no turns to establish orbit. I've seen a lot of craft on here and I'm sitting here asking myself, what am I doing wrong (the thread I linked off to contains the booster segment in my second post). It feels like drag as smaller launches for satellites on a new platform are working well as my space program techniques are refined (I get the Mach effect and have to use SAS to stabilize or else be flipping back to the ground in the SSTO booster so I feel I designed the vessel wrong)

If you're coming back to KSP after a long absence-- by any chance was your last experience prior to 1.0, which came out a bit over a year ago?

They totally overhauled the way aerodynamics works, so you really need to change accordingly-- both in terms of designing and piloting.

However, this question is really a whole topic in its own right.  I'd suggest posting this question all by itself in a separate thread, with an appropriate title (e.g. "How can I get this spacecraft to orbit?"), and post a screenshot of the ship with your post.

 

1 hour ago, Guardian Hope said:

Orbit of Kerbin

• Can I dock a spacecraft at an orbital station for refueling (I do have a number of mods from KIS to KAS and than some - not reflected in the post I linked off to as I didn't have them then)?
• Can I dock multiple components to create a larger spacecraft in orbit of Kerbin?

Sure, that's one of the fun parts of the game.    Docking ports are a stock feature, and once docked you can transfer resources and crew around as you like.

 

1 hour ago, Guardian Hope said:

Planetary Assist Maneuvers

• My space program, as I stated, is obviously at a very early era with it just beginning to create craft capable of orbiting Kerbin. However, I successfully launched an automated craft that reached 11,000+m/sec and was plotted on Kerbin's escape before it was destroyed. What I am trying to figure out (and I have been reading) is how do I make the cross over maneuver to intercept a planet's orbit? (I think I have started to figure out how to do the orbital assists but getting to the planet is a bit harder). I see the alignment come up on my map when I set the target with the time, degrees, and delta-v needed I think. I am just not sure if that's what I am supposed to follow.

Easiest way is generally to use some tool.  There are mods for that, but I prefer to just use http://ksp.olex.biz ; it's simple and easy.  There are other similar tools out there, too, that one just happens to be my personal favorite.  Other folks can chime in. 

1 hour ago, Guardian Hope said:

Intercepting the target Spacecraft

• When I select a planet as a target, KSP can give me what I believe is the appropriate information if what I said above is true. Now I'm just trying to figure out how to intercept a spacecraft moving 3,000 m/sec and move my Kerbalnauts from the first craft to the rescue craft. Can I just EVA them at a close enough range?

Sure, but you'll need to match velocities, first.  Orbital rendezvous is a whole skillset to develop-- if you're trying to figure out and having difficulty with it, I'd suggest posting a separate thread just for that one thing.

1 hour ago, Guardian Hope said:

Returning to Kerbin

• KSC has no beacon. No ILS marker. Nothing. How exactly am I supposed to return to KSC in a spacecraft. So far my spacecraft have been pods so it didn't matter where on the planet they landed but I'm constructing a spaceplane for the final descent so landing at KSC which has a runway would be helpful. Knowing this would allow me to calculate a de-orbit trajectory.

The easy way is to just park a flag or a ship at KSC and look for its icon in map view.    You can also set it as a target.

Or just design a plane that can land on any reasonably flat surface-- it doesn't have to be the runway.  Honestly, I've found it easier to find a reasonably flat surface and just land, than to get precisely lined up with the runway and come to a full stop without tipping over the edge.

1 hour ago, Guardian Hope said:

Reverse Thrusters - we're talking about a multi-stage interplanetary mission. We'll obviously need to slow the spacecraft down before reaching Kerbin descent. Is it even possible to mount reverse thrusters such as SRBs?

Certainly.  SRBs wouldn't be a very good choice-- they have crappy Isp, they belong on the launchpad.  You'd have much more effective retro-thrust by just using your main engines.

Also... you can use a heat shield, so that you don't have to slow down so much with rockets.  Use the atmosphere to slow you down.

1 hour ago, Guardian Hope said:

Miscellaneous

• I think I am doing something wrong with the radial decouplers. When I try to decouple the SRBs from first stage they don't actually decouple and stay attached. You can see and hear the decouple effects. This is with the stock radial decouplers.

My guess is that you're actually attaching your SRBs-or-whatever to the body of the ship instead of to the decouplers.  Would need to see a screenshot to say for sure, though.

 

[bewing]

1 hour ago, Guardian Hope said:

So, I have a predicament. I have been playing KSP which I have owned for a while and although I only got about 20 hours under my belt since the Early Access days (don't really have time to play games) I have gotten back into it. Well, I inadvertently launched a test orbital ship into space with enough power to break Kerbin orbit and enter into what appears to be a stable elongated orbit of the sun (read it all as it goes down here: 

Heh! Great writeup.

I guess my first point has to be that your rockets are much bigger than they need to be. To manage this feat, you need maneuverability. Which means a small, very efficient upper stage, with a lot of fuel. It is easy to design a small rocket that can achieve the speeds that you need -- but you need to use higher tech stuff. SRBs and liquid engines can get you into LKO -- but your upper stage probably needs to be either nuclear or ion-powered. With drop tanks to save weight.

1 hour ago, Guardian Hope said:

Launching from KSC

• My first thought was SSTO

SSTO is fancy stuff. You don't want to get fancy and try doing a desperate rescue mission at the same time. You want a big fat booster to lob a smallish intercept vehicle into LKO. It's nicest if the booster makes it to LKO also, but that's starting to be fancy stuff again.

1 hour ago, Guardian Hope said:

Orbit of Kerbin

• Can I dock a spacecraft at an orbital station for refueling (I do have a number of mods from KIS to KAS and than some - not reflected in the post I linked off to as I didn't have them then)?
• Can I dock multiple components to create a larger spacecraft in orbit of Kerbin?

Absolutely to the first. I'd limit myself to two components, for the second. When you dock things together, they start to wobble a bit. The more you link the more wobble you get. It can become a big problem.

1 hour ago, Guardian Hope said:

Planetary Assist Maneuvers

• My space program, as I stated, is obviously at a very early era with it just beginning to create craft capable of orbiting Kerbin. However, I successfully launched an automated craft that reached 11,000+m/sec and was plotted on Kerbin's escape before it was destroyed. What I am trying to figure out (and I have been reading) is how do I make the cross over maneuver to intercept a planet's orbit? (I think I have started to figure out how to do the orbital assists but getting to the planet is a bit harder). I see the alignment come up on my map when I set the target with the time, degrees, and delta-v needed I think. I am just not sure if that's what I am supposed to follow.

Gravity maneuvers are tricky things, and you are limited to very specific windows of time. Timing is crucial, in fact. They take years to set up. They take years to execute. They are for missions which are not under any time pressure.

1 hour ago, Guardian Hope said:

Intercepting the target Spacecraft

• When I select a planet as a target, KSP can give me what I believe is the appropriate information if what I said above is true. Now I'm just trying to figure out how to intercept a spacecraft moving 3,000 m/sec and move my Kerbalnauts from the first craft to the rescue craft. Can I just EVA them at a close enough range?

Yes, to make this work at all, you will intercept within a few hundred meters and match speeds. Then you will EVA the Kerbonauts across. If you can manage to get the rescue vehicle within a few thousand kilometers of the target at a low relative speed, then the actual rescue process will be trivially easy.

According to your orbits, launching now will be a good idea. You will probably intercept the Mara SLA01 around the orbit of Duna. Then you burn like mad to match its speed.

1 hour ago, Guardian Hope said:

Returning to Kerbin

• KSC has no beacon. No ILS marker. Nothing. How exactly am I supposed to return to KSC in a spacecraft. So far my spacecraft have been pods so it didn't matter where on the planet they landed but I'm constructing a spaceplane for the final descent so landing at KSC which has a runway would be helpful. Knowing this would allow me to calculate a de-orbit trajectory. 
• Reverse Thrusters - we're talking about a multi-stage interplanetary mission. We'll obviously need to slow the spacecraft down before reaching Kerbin descent. Is it even possible to mount reverse thrusters such as SRBs?

Getting the rescuees back to LKO and reentering are two completely separate processes. You will probably want two separate ships to do them with. The rescue ship returns to LKO, then everybody EVAs or transfers over to another ship that does the reentry. Getting the reentry ship to land at KSC is fancy -- and I already said you probably don't want to be worrying about how to be fancy at this point.

1 hour ago, Guardian Hope said:

Miscellaneous

• I think I am doing something wrong with the radial decouplers.

Yes, as snark said, you are almost certainly missing when you are trying to attach things to the decouplers. If they are properly attached, they will be obviously separated from the main body of the rocket by the decoupler.

 

[Guardian Hope]

On 7/6/2016 at 9:58 PM, Snark said:

If you're coming back to KSP after a long absence-- by any chance was your last experience prior to 1.0, which came out a bit over a year ago?

They totally overhauled the way aerodynamics works, so you really need to change accordingly-- both in terms of designing and piloting.

However, this question is really a whole topic in its own right.  I'd suggest posting this question all by itself in a separate thread, with an appropriate title (e.g. "How can I get this spacecraft to orbit?"), and post a screenshot of the ship with your post.

 

@Snark, I want to thank you for responding to my questions so quickly!

I am indeed coming back to KSP after a very long absence. I believe the last version of the game I played prior to now was .73 or .83 so it was definitely before 1.0 hit.

I will definitely have to read up and post accordingly on that subject as it seems anything larger than a single rocket or if it's on the taller side even with stabilizers, RCS, etc. rockets will start to rather unrealistically bend until one or more engines run out of fuel at which point it's already hit KSC and the surrounding area or lifts off far enough to eject the command pod for it to safely return to the ground. That design was based off the SLA01 which reached Kerbin escape and is now incidentally orbiting the sun and thus only the second rocket of its design I have made which had multiple engines and make it off the launch pad. Even a pseudo-space shuttle couldn't make it off the launch pad and that far downrange (maybe, maybe 17 KM from KSC before crashing). The segment I posted can reach space but doesn't have enough fuel to establish orbit. 

On 7/6/2016 at 9:58 PM, Snark said:

Sure, that's one of the fun parts of the game.    Docking ports are a stock feature, and once docked you can transfer resources and crew around as you like.

Excellent! I have noticed this in KSP and I also know its true in rule rocketry science but about 80% of the total fuel supply (solid and liquid combined as an aggregate) is burned to just reach LEO or rather LKO since Kerbin isn't technically Earth. Having a station to resupply for the journey and attach all the parts of the craft would make such an endeavour much easier. 

On 7/6/2016 at 9:58 PM, Snark said:

Easiest way is generally to use some tool.  There are mods for that, but I prefer to just use http://ksp.olex.biz ; it's simple and easy.  There are other similar tools out there, too, that one just happens to be my personal favorite.  Other folks can chime in. 

That tool is extremely helpful. It was able to calculate a fairly good trajectory for a test flight. I have bookmarked it; this will definitely come in handy.

 

On 7/6/2016 at 9:58 PM, Snark said:

Orbital rendezvous is a whole skillset to develop-- if you're trying to figure out and having difficulty with it, I'd suggest posting a separate thread just for that one thing.

 

After a few test flights, I think I have hammered down orbital rendezvous in Kerbin orbit both with two crafts already in orbit and one launch from KSC to intercept an already orbiting craft. For the purposes of my test, the velocity or the craft being intercepted was about 4,000 m/sec (the Mara SLA01 orbits at 3,000-3,600 m/sec around the sun). The closest I have brought a craft was 250 meters which for a first few tries I do believe is pretty good. However, this was using a nuclear propellant which will likely be the propellant of choice for the later stage rescue mission (I could not get Ion to work: while I had the Argon gas, it required megajoules which I thought solar panels would provide since joules were just a measure of energy but I was most definitely wrong). Between nuclear and ion, ion was definitely more efficient it seemed and a lot less heavy.

 

On 7/6/2016 at 9:58 PM, Snark said:

The easy way is to just park a flag or a ship at KSC and look for its icon in map view.    You can also set it as a target.

Or just design a plane that can land on any reasonably flat surface-- it doesn't have to be the runway.  Honestly, I've found it easier to find a reasonably flat surface and just land, than to get precisely lined up with the runway and come to a full stop without tipping over the edge.

The flag option didn't work (nothing appeared on the map) but I did park a purpose built solar and battery powered rover at KSC just short of the runway and than a flag (in case I forgot) with the heading information (True HDG 088 / Relative HDG 090).

It's unfortunate KSP doesn't have ILS (Instrument Landing System for the uninitiated) and LOC (Localizers) but knowing where KSC is, the runway's true and relative heading, and my final planned descent speed should give me a reasonable estimation of where I need to be at 2,000 feet (about 610 meters) in altitude relative to the ground to line up for landing (Flight Simulator X and Orbiter can teach a lot of this).

 

On 7/6/2016 at 9:58 PM, Snark said:

Certainly.  SRBs wouldn't be a very good choice-- they have crappy Isp, they belong on the launchpad.  You'd have much more effective retro-thrust by just using your main engines.

Also... you can use a heat shield, so that you don't have to slow down so much with rockets.  Use the atmosphere to slow you down.

My guess is that you're actually attaching your SRBs-or-whatever to the body of the ship instead of to the decouplers.  Would need to see a screenshot to say for sure, though.

 

I found the rotate object button to change the direction of engines. The reason I asked this question is because I have noticed that my craft tend to be too heavy that on descent they start gaining speed even with a heat shield against the friction of the atmosphere. In fact, in some cases, my descent goes from about ~170 m/sec to over 2,700 m/sec which makes descent very quick but also the destruction of the spacecraft. Once entering orbit of Kerbin again I will definitely need a "fool proof way" of slowing down during atmospheric reentry and while heat shields have allowed me to survive the absurd 2,700 m/sec reentries I have committed, I can't say they have helped me slow down one bit. It definitely won't be SRBs on re-entry as they have no finite control; it'll have to be a small tank of expendable fuel.

As for the SRBs not decoupling, I didn't get a screenshot (will try to) but what I did notice with my last launch is that the decouplers actually detach from the spacecraft and are visible but don't take anything with them. They look perfectly aligned with the SRBs that get attached but maybe they are not.

On 7/6/2016 at 11:19 PM, bewing said:

Heh! Great writeup.

I guess my first point has to be that your rockets are much bigger than they need to be. To manage this feat, you need maneuverability. Which means a small, very efficient upper stage, with a lot of fuel. It is easy to design a small rocket that can achieve the speeds that you need -- but you need to use higher tech stuff. SRBs and liquid engines can get you into LKO -- but your upper stage probably needs to be either nuclear or ion-powered. With drop tanks to save weight.

 

Thank you @bewing for also replying quickly. I have begun testing with nuclear and ion engines. As I stated in my response to @Snark, ion engines didn't work unless I opened the debug menu and turned "infinite fuel" on (which is no fun). While I had the Argon gas required for the type of ion engines I was using, it also required megajoules which I thought would be provided by the deployable solar panels and rechargeable batteries. Nuclear worked like a charm but seemed like it will burn through a lot of fuel (so lots of expendable tanks) and nuclear is much heavier so getting it out of Kerbin's sphere of influence seems like it would be more challenging. 

 

On 7/6/2016 at 11:19 PM, bewing said:

SSTO is fancy stuff. You don't want to get fancy and try doing a desperate rescue mission at the same time. You want a big fat booster to lob a smallish intercept vehicle into LKO. It's nicest if the booster makes it to LKO also, but that's starting to be fancy stuff again.

Absolutely to the first. I'd limit myself to two components, for the second. When you dock things together, they start to wobble a bit. The more you link the more wobble you get. It can become a big problem.

Gravity maneuvers are tricky things, and you are limited to very specific windows of time. Timing is crucial, in fact. They take years to set up. They take years to execute. They are for missions which are not under any time pressure.

Well small with powerful boosters did create this situation in the first place. The Mara SLA01 was intended for deploying satellites unmanned into Kerbin orbit but on its manned test flight it escaped Kerbin and entered into orbit of Kerbol. One thing I want to make sure doesn't happen is that fuel doesn't run out this time around: the rescue spacecraft (Mara One) needs to have enough fuel to make the trip to intercept the SLA01 including any adjustments and be able to maneuver into a position that gives it the speed of the SLA01 and a distance gap reasonable enough for the Kerbals to EVA over.

One thing I have noticed is that 80% of the total aggregate fuel supply is burned up during launch for liquid and solid fuel. With nuclear and ion there appears to be a lot more headroom but ion has not gotten a true test due to the fact nothing I can find supplies the megajoules needed to burn the engines (had to use the debug menu to try out ion engines).

 

On 7/6/2016 at 11:19 PM, bewing said:

Yes, to make this work at all, you will intercept within a few hundred meters and match speeds. Then you will EVA the Kerbonauts across. If you can manage to get the rescue vehicle within a few thousand kilometers of the target at a low relative speed, then the actual rescue process will be trivially easy.

According to your orbits, launching now will be a good idea. You will probably intercept the Mara SLA01 around the orbit of Duna. Then you burn like mad to match its speed.

Getting the rescuees back to LKO and reentering are two completely separate processes. You will probably want two separate ships to do them with. The rescue ship returns to LKO, then everybody EVAs or transfers over to another ship that does the reentry. Getting the reentry ship to land at KSC is fancy -- and I already said you probably don't want to be worrying about how to be fancy at this point.

Yes, as snark said, you are almost certainly missing when you are trying to attach things to the decouplers. If they are properly attached, they will be obviously separated from the main body of the rocket by the decoupler.

 

This will definitely be harder. The SLA01 is out of fuel and traveling at a consistent 3,000-3,600 m/sec so that means the Mara One Rescue Ship will need to match that speed since the SLA01 is running on empty fuel. Hitting a few hundred meters will hopefully be doable - I've done it in Kerbin orbit with nuclear engines at a bit over 4,000 m/sec. 

To get everything put together and put through the trials in and around Kerbin I estimate that at least a few in-game months (probably half a year) will pass. I have no vehicle built and no infrastructure setup yet in and around Kerbin capable of handling this mission. I intend to launch an orbital station to support the mission into LKO.

My plan was to separate a spaceplane (more of a space shuttle versus the idea we all get get when we say "spaceplane") design from the main spacecraft for the de-orbit and reentry. A retrograde burn to slow the vehicles down before detaching versus trying to intercept the orbital station (which I've started to name "Orbital One"). One thing Orbiter and FSX taught me is that it's a lot easier to land on the ground when you know where it is versus trying to intercept another moving object when every ounce of fuel counts. Especially Orbiter and landing back at Cape Canaveral. Now that I know where KSC is (thanks to my rover) this is the part I am least worried about. What I am worried about is slowing down on atmospheric reentry - only my earliest of spacecraft have not burned up on reentry due to the speed and atmospheric friction causing high thermal stress,

[bewing]

1 hour ago, Guardian Hope said:

To get everything put together and put through the trials in and around Kerbin I estimate that at least a few in-game months (probably half a year) will pass.

You need practice before you do any of this. You should start a sandbox game (you can have multiple games going at one time) and use it for practice. Practice building ships. Practice intercepting. Practice docking. Practice landing. There is no way in heck that you will be able to do any of this the very first time, without practice. You have a goal in the game, and that is good. It gives you an incentive to strive for. But it is a very ambitious goal for someone so new to this version of the game. 

The problem is that you don't have half a year. You don't have months. Your fully functional and tested rescue ship needs to launch within a few game weeks. It will take a very long time to reach its intercept point. And you need to know that you have the skills to pilot it before you launch it. Your SLA01 ship has been traveling for quite a while, and it is on the opposite side of Kerbol from KSC. That makes for a serious orbital complication.

-- Oh, and as far as powering ion drives goes: an ion drive uses 8 zaps per second, at full thrust. A gigantor solar array produces a little over 24 zaps per second of electricity at Kerbin's orbit. So two gigantors (you want to balance them in pairs) will power about 6 ion drives.

Edited July 10, 2016 by bewing