Kerbal Space Program

[warpus]

Antilogic, mun survey missions sound like fun!

I think I am going to start a new career game when I get home. During my first trial run one of my guys got stuck in space.

I think they need to change it so that you don't have access to modules capable of carrying kerbalnauts until you unlock a bit of the tech tree. I realize that kerbals are important to the concept of the game and all, but it just doesn't seem to make sense to have it set up the way it is now. It's too easy to get them killed or stuck in space, without more advanced parts available. Sending probes into space during your first couple runs would be a lot more.. balanced, I think.

 

[GAGA Extrem]

That's what they have done. Sorta.
Kerbals can no longer go on EVA unless you have upgraded the astronaut complex and they can't take surface samples unless you upgrade your science facility.
So no fancy-pants Minmus missions for 2000 science on day 2 anymore

 

[warpus]

The EVA thing I like, but it still seems weird and unbalanced that you start off with a module capable of carrying kerbalnauts into space. I started a new game though and so far so good - maybe I'll get used to this and will stop complaining about it.

 

[Antilogic]

I'm more confused by the scientific instruments and the manned v. unmanned thing. I think the first manned mission I launch is a Mercury-style with a pressure and temperature monitor to make sure the capsule is airtight and livable. Instead I have the weird goo and materials science bays.

Oh, screenshot time. Here's my Munar Surveyor falling towards the Mün on its first mission:

Spoiler :

And here's the Flyer, my cheap Kerbin surveyor, at least for the nearby locations. It has huge lift, can easily take off at 20% throttle. I'll need a heavier craft for the stuff on the other side of the globe:

Spoiler :

I'm also really frustrated right now because I stuck a bunch of temperature probes on my Munar Surveyor to create the Munar Temperature Surveyor (MTS). However, I used the tools to push the thermometers a little closer to the hull, and now that I am in orbit the Mun I have just discovered I can't click on the temperature probes and record measurements. And as far as I know there is no way to cycle through the parts or assign functional groups to them in flight. So I'm really angry, don't know what to do. I might try some save-game editing to fix the positions.

 

[Rubin]

Quick question: Has any of you experts managed a manned Single-Stage-To-Orbit rocket using the default parts in 0.90 career mode?

I've read about the possibility of using 10 FL-T200 fuel tanks and the LV-T30 liquid fuel engine, but I have no idea how to pull it off. My crude calculations even predict it impossible (less than 4000 delta-V).

 

[J-man]

With airbreathing engines it would become much easier but a pure rocket SSTO shouldn't be that hard. Use aerospike engines and don't use too much parts that aren't engines or fuel tanks.

 

[Rubin]

With airbreathing engines it would become much easier but a pure rocket SSTO shouldn't be that hard. Use aerospike engines and don't use too much parts that aren't engines or fuel tanks.

[My emphasis]

Yup, that's what I keep reading

In the past 6 months I've been trying to successfully reach orbit with a simple rocket SSTO. So far with a 100% failure rate.

My latest failed attempt (now using the Aerospike engine, see attached image) at 14.3 tonnes (3 4.3 tonnes dry) should have delta-V of almost 6000 just over 4500. It should be possible. If I use an LV-T30 engine instead, the delta-V drops below 4000, indicating a flaw in the rocket design in order to reach orbit.

 

[J-man]

[My emphasis]

Yup, that's what I keep reading

In the past 6 months I've been trying to successfully reach orbit with a simple rocket SSTO. So far with a 100% failure rate.

My latest failed attempt (now using the Aerospike engine, see attached image) at 14.3 tonnes (3 tonnes dry) should have delta-V of almost 6000. It should be possible. If I use an LV-T30 engine instead, the delta-V drops below 4000, indicating a flaw in the rocket design in order to reach orbit.

A 6000m/s delta v rocket should reach orbit easily. Perhaps you use a sub optimal ascend. Scott Manley has a great tutorial on this:

https://www.youtube.com/watch?v=F0KiePxOuuc&index=3&list=PLYu7z3I8tdEmqpOkQZCl5SZB5t0vXuxE0

 

[Rubin]

Thanks, J-man, and yes, my ascend is sub-optimal, but I'm not sure by which magnitude. I managed 2000 m/s at about 75 km with the LV-T30 setup using a "standard" 10 km 45 degree gravity turn; and only 2200 m/s with the Aerospike turning at about 15 km. There's room for improvement, sure, but I'm blind when it comes to understanding the "easy" part of what I'm trying to do (unless I'm just a really poor rocket pilot, which may be the case).

Also, it's fairly hard to find information on rocket SSTOs, because most SSTOs are jet/plane variants.

[Edit]: I drastically miscalculated the delta-V of the Aerospike version. It's not close to 6000, rather it's just slightly over 4500. Hence, my real issue probably lies in the rocket design.

 

[Rubin]

I had to abandon the idea of a pure rocket SSTO in early game career mode, and just do two 2-stage-to-orbit launches before advancing technologies. (I try to do a 100% reusable play with just a single kerbal pilot; recruiting the rest of the crew from the kerbals stranded in orbit.)

Here's my latest hybrid jet/rocket SSTO. I'm not sure I like it. It feels overbuilt and quite inefficient, but it does weigh less than 11t, and it was super easy to put together once airbreathing technologies became available.

 

[Ghpstage]

Quick question: Has any of you experts managed a manned Single-Stage-To-Orbit rocket using the default parts in 0.90 career mode?

I've read about the possibility of using 10 FL-T200 fuel tanks and the LV-T30 liquid fuel engine, but I have no idea how to pull it off. My crude calculations even predict it impossible (less than 4000 delta-V).

That kind of arrangement with 9 FL-T200s certainly works, I just uploaded a video of it. I see no reason why a 10 fuel tank variant shouldn't work.
Are you perhaps going full throttle all the way up? A rule of thumb is that if your moving at more than 200m/s at altitudes lower than 8km then your feeding fuel to the drag monster.

My best creation has been a low tech, low cost probe that can land on the Mun under battery power (Video) when the only techs you have are Flight Controls, Science Tech and their prerequisites (total 110 science points). It actually has far more dV than is needed for this, upgraded with solar panels it can carry out the exploration contracts at Mimus, Duna, Eve, Jool, Laythe and, aerobraking chaos allowing, Ike, Gilly and probably one or two more Jool moons.

 

[Rubin]

That kind of arrangement with 9 FL-T200s certainly works, I just uploaded a video of it. I see no reason why a 10 fuel tank variant shouldn't work.
Are you perhaps going full throttle all the way up? A rule of thumb is that if your moving at more than 200m/s at altitudes lower than 8km then your feeding fuel to the drag monster.

My best creation has been a low tech, low cost probe that can land on the Mun under battery power (Video) when the only techs you have are Flight Controls, Science Tech and their prerequisites (total 110 science points). It actually has far more dV than is needed for this, upgraded with solar panels it can carry out the exploration contracts at Mimus, Duna, Eve, Jool, Laythe and, aerobraking chaos allowing, Ike, Gilly and probably one or two more Jool moons.

Thanks a lot for that video, Ghpstage

A few notes: You did have SAS and maneuver nodes available to assist your ascend (which is better than mine, although I do something similar, just less successfully), but then again, you did bring a full load of capsule monopropellant into orbit The craft is less than 10% reusable, but it looks like that saves you a critical amount of delta-V. My calculations show about 4100 delta-V for the craft, and you've proved that the setup is indeed possible of reaching orbit.

 

[Ghpstage]

Thanks a lot for that video, Ghpstage

A few notes: You did have SAS and maneuver nodes available to assist your ascend (which is better than mine, although I do something similar, just less successfully), but then again, you did bring a full load of capsule monopropellant into orbit The craft is less than 10% reusable, but it looks like that saves you a critical amount of delta-V. My calculations show about 4100 delta-V for the craft, and you've proved that the setup is indeed possible of reaching orbit.

You have access to SAS at any point, just put a pilot in the command pod.
Manoeuvre nodes would be available as the vid was made on sandbox, they aren't important for achieving orbit though.
I'm so used to not using those things at this point that it took a while to realise I had SAS and I didn't bother with nodes. The second link I posted had me land a probe on the Mun without either
You used the atmospheric ISP to calculate the dV didn't you? Don't forget that for an SSTO a lot of the burn will be going on in orbit and the transition areas so your effective ISP is considerably higher than at sea level. I asked about this on the KSP forums yesterday in fact, and I was recommended to use vacuum ISP for all calcs as the standard 4400dV to orbit value was gained using vacuum ISP's.

It is possible to recover 100% of this thing, but you need to clip the engine and tanks into an are the size of a single fuel tank, and the parachute down through the command pod as far as it will go. It'll then survive most upisde down landings on land. It is a bit cheaty, but its still interesting as an experiment.

 

[Rubin]

You have access to SAS at any point, just put a pilot in the command pod.
Manoeuvre nodes would be available as the vid was made on sandbox, they aren't important for achieving orbit though.
I'm so used to not using those things at this point that it took a while to realise I had SAS and I didn't bother with nodes. The second link I posted had me land a probe on the Mun without either

Skilled players don't need the extra information from the upgraded Tracking Station, and they probably don't need SAS, although I've found SAS to be a big help in stabilizing the craft. Alas, I'm no skilled pilot, and with version 0.90 those unmanned command modules suddenly become very attractive for launches without a Kerbal pilot. In my current game I wanted a Kerbal scientist in orbit, so there was no room for a proper pilot. Self-imposed challenges and restrictions are a lot of fun.

You used the atmospheric ISP to calculate the dV didn't you? Don't forget that for an SSTO a lot of the burn will be going on in orbit and the transition areas so your effective ISP is considerably higher than at sea level. I asked about this on the KSP forums yesterday in fact, and I was recommended to use vacuum ISP for all calcs as the standard 4400dV to orbit value was gained using vacuum ISP's.

I indeed used the atmospheric ISP in the calculations. Your "9 FL-T200" craft has 4190 delta-V (atmospheric) and 4845 delta-V (vacuum). I mostly use the calculations to check if the craft design makes sense and if redesigns make any drastic changes. The way I understand it is that the delta-V changes when fuel is burned, so calculations are approximations at best.

It is possible to recover 100% of this thing, but you need to clip the engine and tanks into an are the size of a single fuel tank, and the parachute down through the command pod as far as it will go. It'll then survive most upisde down landings on land. It is a bit cheaty, but its still interesting as an experiment.

Yeah, that's not quite the reusable SSTO I had in mind.

 

[Ghpstage]

Skilled players don't need the extra information from the upgraded Tracking Station, and they probably don't need SAS, although I've found SAS to be a big help in stabilizing the craft. Alas, I'm no skilled pilot, and with version 0.90 those unmanned command modules suddenly become very attractive for launches without a Kerbal pilot. In my current game I wanted a Kerbal scientist in orbit, so there was no room for a proper pilot. Self-imposed challenges and restrictions are a lot of fun.

Indeed they are!
I took on a challenge in my latest hard carer, to never take a random contract before the scripted ones are all complete. Getting the Minmus intercept with my probe was a bit hairy, but it actually got quite easy for a long while after due to access to nodes. So I made the restrictions steeper, I now can't upgrade any buildings apart form the ones needed for manoeuvre nodes and if possible I want to put Stayputnik's on every body in the solar system.
Which leaves me with relatively early tech, sub 18 ton, 30 part rockets and no SAS with which to land on every planet (bar Jool) and moon in the solar system!
The Stayputnik drones have gone to many places so far,
The Mun, Minmus, Duna, Ike, Gilly, Jool, Bop and Pol, With more heading to Dres, Vall, Laythe and Tylo currently. I've had a few mishaps, like running out of fuel at Ike, Gilly and Tylo, and a 7km/s flyby past Moho
...
Unfortunately, effective piloting of the thing I came up with for future missions to Tylo and Moho is, well, pretty much impossible. I can reliably get it to orbit, but the dV left when in orbit ranges from 5800 to 7200
I'll have to see if wings or something can help stability as it tends to spin and wander. A lot.

I indeed used the atmospheric ISP in the calculations. Your "9 FL-T200" craft has 4190 delta-V (atmospheric) and 4845 delta-V (vacuum). I mostly use the calculations to check if the craft design makes sense and if redesigns make any drastic changes. The way I understand it is that the delta-V changes when fuel is burned, so calculations are approximations at best.

Actually when in a stable orbit dV is pretty damn accurate, as the equation takes into account the mass changes that happen during a burn. Getting out of the atmosphere however, does require a somewhat unpredictable amount. Mostly depending on your throttle control and flight path due to atmospheric and gravity drag.
I personally like the standardised conversion of 4550 vacuum dV to orbit, which takes into account a lot of the losses expected when flying well, as it gives me some feedback on how well I did actually fly.

Yeah, that's not quite the reusable SSTO I had in mind.

I don't think you can expect a fully re-useable SSTO which can achieve anything beyond that goal up until jet engines and 48-7s, at that point, rescue and light satellite launching SSTO's will both probably be achievable. You can go the the Mun and come back with fewer than 30 parts and while under 18 tons afterall!

 

[coanda]

Got this game as a gift over the holidays; I've been having a blast with it.

The tutorials were glitchy as heck for me, so I eventually gave up on them and have been just winging it. After some false starts, I got a career mode game going to the point where I reached the Mun. Unfortunately, I didn't have the fuel to make it back from the Mun.

So... I've got a Kerbalnaut just chillin' on the Mun watching the scenery until I can figure out how to get a rescue rocket out. Which will probably require upgrading my VAB, because I'm not seeing a way to make a lunar lander capable of picking him up and getting back down on Kerbin with only 30 parts.

 

[Antilogic]

Has there been a change in how nuclear engines work? I have a craft en route to Duna, and for some reason the nuclear engines are not working anymore. Tooltip indicates it is because they flamed out due to a lack of oxidizer, but they are directly connected to full tanks and have feeder lines from a central orange tank.

I can still toggle the engines, so they are still attached to the craft. And it's piloted with a crew, and there's power, so that's not the problem.

I'm really confused.

 

[GAGA Extrem]

Are you sure the fuel lines are connected in the right direction and that the tanks are actually filled with oxidizer? You can alter the amount of liquid fuel and oxidizer during construction - and it may happen by accident. ANd I have managed more than one time to attach a fuel line wrong way, especially when the distance is short and you can't see the arrows properly.

Either way: Try pumping the fuel manually into the NV engine tanks and check if it works afterwards. Try to have the same amount of fuel in the tanks to avoid assymetric weight (= spinning).

 

[Daedwartin]

Actually when in a stable orbit dV is pretty damn accurate, as the equation takes into account the mass changes that happen during a burn. Getting out of the atmosphere however, does require a somewhat unpredictable amount.

Actually:

This unpredictable amount is not in fact unpredictable. It is known to be 4.45-4.7 km Delta-V, and is going to generally be half your delta-v. It goes down to 3.5 km Delta-V if you have Ferram Aerospace.

 

[Antilogic]

I'll take a picture when I can and upload it. Long story short, I know the fuel lines are going in the right direction because I used this to burn out of Kerbin's orbit. The central orange tank is partially emptied while the separate nuke tanks are completely filled.

Problem started after time acceleration in interplanetary space, don't know if that caused it.