NLSSTO Released

[Eagle]

http://orbithangar.com/searchid.php?ID=3521

So I finally got around to releasing my favorite addon (It must be Tuesday). I'm excited to hear any feedback (both love and hate). I have some ideas for continuing the series, but nothing will be ready until next Tuesday. :rofl:

It is a 'realistic' craft, so (despite copious delta v) watch your fuel, and its not very nice to exceed 3g's by much on launch or the human limit on reentry.

 

[Arrowstar]

It ain't pretty, but if it gets the job done... I'll give it a try!

 

[Andy44]

Okay, I think this might be cool, but I ran into some problems:

1. The readme doesn't seem as helpful as it should, since it doesn't explain what is what, NLO, NLSSTO, etc., is a bit confusing.

2. During launch, the vehicle keeps tryint to pitch up to vertical until a high altitude is reached. Is it supposed to do this? You have to keep pressure on the joystick and muscle it into the correct attitude.

3. I ran the scenario starting from the launchpad, and launched into a 28.6 deg, 200km orbit with 1% fuel remaining. I hit the J key and the LES tower jettisoned, hit J again, and the Gemini-looking vehicle (is this the NLO?) separated from the booster. Used the capsule's thrusters to deorbit, hit J key again, CTD. No idea what was supposed to happen.

I'm not sure if I'm doing this right. Perhaps the readme should run you through each mission phase step-by-step. This looks like a cool space vehicle and I've been waiting for this one.

 

[Missioncmdr]

3. I ran the scenario starting from the launchpad, and launched into a 28.6 deg, 200km orbit with 1% fuel remaining. I hit the J key and the LES tower jettisoned, hit J again, and the Gemini-looking vehicle (is this the NLO?) separated from the booster. Used the capsule's thrusters to deorbit, hit J key again, CTD. No idea what was supposed to happen.

I also encountered that same error.

 

[Eagle]

Okay, I think this might be cool, but I ran into some problems:

1. The readme doesn't seem as helpful as it should, since it doesn't explain what is what, NLO, NLSSTO, etc., is a bit confusing.

2. During launch, the vehicle keeps tryint to pitch up to vertical until a high altitude is reached. Is it supposed to do this? You have to keep pressure on the joystick and muscle it into the correct attitude.

3. I ran the scenario starting from the launchpad, and launched into a 28.6 deg, 200km orbit with 1% fuel remaining. I hit the J key and the LES tower jettisoned, hit J again, and the Gemini-looking vehicle (is this the NLO?) separated from the booster. Used the capsule's thrusters to deorbit, hit J key again, CTD. No idea what was supposed to happen.

I'm not sure if I'm doing this right. Perhaps the readme should run you through each mission phase step-by-step. This looks like a cool space vehicle and I've been waiting for this one.

1. Sorry, NLSSTO is the big white rocket, NLO is the command module/service module stack that looks like gemini. NLCM is the reentry module.

2. Yes its supposed to do that. The rocket would prefer to fly ass first (for reentry). Keeping the gear down reduces that somewhat, but if you pitch down a little the pitch up will help you keep attitude.

3. I screwed up. NLO.ini is was looking for the a different .ini for payload. I'm uploading a fix.

As for the fuel concerns, I have reached 200x200 with 2.5% In the tanks. What is important is to stay above 70 degrees until you pass 30 km(above max q), then even off. I jettison the LES at about 60km. The vessel has 11 kms delta v, you only need a little over 10 for LEO.


-----Posted Added-----


Its updated, if you already have the addon downloaded. Sorry about the oversight.

 

[DanP]

As you know, I've been looking forward to flying the NLSSTO, because I really like the concept.

Some feedback...

Cool ride! I made a couple of ascents and attempted a reentry. Good visuals IMO.

It's really cahllenging to fly. The fuel budget is low, and ascent is tricky the first few times. The really hard part is reentry. It could be just me, because I never managed to do a proper reentry in a capsule, only spaceplanes, so being closer to the former than the latter, NLSSTO is a bit tricky for me. I dropped very steeply and deccelerated vicously in the lower atmosphere. I did end up with only 600m/s at 10km and tried to transition to a vertical attitude at around 6km to settle her down. However I couldn't hold it nose-high for more than a second. It just kept falling over until I wasn't able to recover and crashed nose first into the ground. I must be doing something wrong, so I'd appreciate any tips.

It's a completely new concept to Orbiter if I'm not mistaken, and it's a lot of fun.

Cheers

 

[Eagle]

It's really cahllenging to fly. The fuel budget is low, and ascent is tricky the first few times. The really hard part is reentry. It could be just me, because I never managed to do a proper reentry in a capsule, only spaceplanes, so being closer to the former than the latter, NLSSTO is a bit tricky for me. I dropped very steeply and deccelerated vicously in the lower atmosphere. I did end up with only 600m/s at 10km and tried to transition to a vertical attitude at around 6km to settle her down. However I couldn't hold it nose-high for more than a second. It just kept falling over until I wasn't able to recover and crashed nose first into the ground. I must be doing something wrong, so I'd appreciate any tips.

It does a (mostly) ballistic reentry so you will want to use MapMFD or Aerobrake MFD(most accurate) to land near a base.

While you're reentering, don't use your attitude thrusters for anything but to roll. Other than that, not much is required until you get subsonic.

You crashed nose first because you dropped your gear to early. With the gear down the craft tries to go nose first. Don't drop the gear until just before landing and you have killrot on.

As you slow down the NLSSTO should right itself. For me it happens at about 6-4 km. It won't go vertical on its own because you still have some ground speed to eliminate. Do a few short bursts at 3-2.5 km to reduce your ground speed. Then pitch up to 90 degrees and engage killrot. At about 2km with killrot on lower gear. I descend at a rate where my vertical speed is 1/10th my altitude (-100m/s at 1km, -50m/s at .5km -10m/s at .1 km). (Dropping gear while hovering just above the ground works too)

I land in external view with Surface MFD in my externalMFD.

I guess the big concern is not to run out of fuel before you land.

 

[DanP]

Thanks a lot for those pointers ! I'll give it another go as soon as I can.

So basically, you're saying put into retrograde on EI and leave the attitude alone until it has deccelerated enough?

How about deorbit burns then? Any tips on how low periapsis should be dipped?

Thanks again.

 

[Eagle]

So basically, you're saying put into retrograde on EI and leave the attitude alone until it has deccelerated enough?

That is exactly what I do. Also, at the entry interface, I enter with up, up. (not the default up = orbit normal).

How about deorbit burns then? Any tips on how low periapsis should be dipped?

Thanks again.

It doesn't seem to matter much how steep you reenter. I usually reenter rather shallow so I have more fuel to land.

Thank you to everyone for trying my addon so far and all the great and important feedback I've received.

 

[Andy44]

Okay, I DL'd the fixed version and it now jetts the service module properly. Although if you use Aerobrake MFD to deorbit the NLO and then jetison the service module, the aerodynamics change drastically and it's almost impossible to land on target.

I"m still not sure how this vehicle's meant to be operated. Are you supposed to land the entire stack, or is the booster meant to seperate and land itself, while the NLO flies its mission and lands later?

 

[Zatnikitelman]

Well, I tried to get this unusual, but interesting craft into orbit using PEG, but it sent me all kinds of directions. It appears from the trajectory line in PEG that it is too shallow for some reason.

 

[Andy44]

You mean the HUD cue from Launch MFD? I used it and it worked just fine. Only thing is that near the end of orbit insertion you need to throttle way back, because when this thing is almost out of fuel it shoves you along at like 8 Gs, which makes it easy to overshoot your target orbit.

 

[Zatnikitelman]

No, I'm talking about the Powered Explicit Guidance here. I use that for any realistic launcher that doesn't have an autopilot and it works great, except on this one. Perhaps I'll figure it out tomorrow.

 

[DanP]

That is exactly what I do. Also, at the entry interface, I enter with up, up. (not the default up = orbit normal).

As in 90 deg. nose high, and not retrograde?

 

[STSJASON]

thanks for the addon but when I try to lunch a missile my desktop crashes

 

[Eagle]

As in 90 deg. nose high, and not retrograde?

As in nose facing retrograde, and roll is level with horizon.


-----Posted Added-----

thanks for the addon but when I try to lunch a missile my desktop crashes

I'm not sure why that's happening. I don't see anything obvious that is causing it. Make sure you're using the most recent version (I updated it the first night to fix another CTD error).

As a small note, make sure you're launching them from the NLKIRack vessel.

If anyone else has the same error let me know.

 

[Jarvitä]

Yeah, I get a CTD every time I try to separate the capsule.

 

[Eagle]

Yeah, I get a CTD every time I try to separate the capsule.

The CTD is caused because I left out NLCM01.ini out of my original release. It is now included at Orbithangar, so if you download it again it will be fixed.

 

[Jarvitä]

The CTD is caused because I left out NLCM01.ini out of my original release. It is now included at Orbithangar, so if you download it again it will be fixed.

Well, actually, I already have the latest version, it turns out the problem was spacecraft3, and the cause was my stupidity when attempting to install it. I've fixed it now, and I must say I really like the capsule. It kind of reminds me of Orion with the small service module.

But, are you actually supposed to deorbit AND soft-land the launcher with 2% fuel? How?:blink:

 

[Eagle]

But, are you actually supposed to deorbit AND soft-land the launcher with 2% fuel? How?:blink:

Enter shallow and save as much fuel as landing as possible. I've been able to land softly with 1.2% fuel after reentry (0.1% remaining after touchdown).

The biggest way to save fuel on landing is to wait longer to brake, and reduce the time you do your slow descent. If you can cancel out your forward speed and soft land at the same time you save the most fuel, but that is a difficult mulit-task. I suggest performing the landing sequence as I indicated above, but wait until .8 km to do the final descent.

If you don't like landing, just consider the NLSSTO first stage as expendable or parachute recoverable. The chute on the command module is good enough to be used above 2km.

The NLSSTO is a challenge to fly (shame on me for poor engineering design, but I like it). Carrying mission modules restricts you to really low orbits because of the extra payload too.