Search Ares V

[Columbia42]

I'm working on having a more accurate KSC for the Sol_Constellation system in the lunar mission scenario. For this purpose, I'm putting in some new surface tiles that are repositioned. (The ones in Orbiter 2006 are off by a few hundred yards). I'm wondering, for the surftiles to work, do they have to be in the textures directory or can they be in the Textures2 directory alone? (I'm asking because I don't want to replace any default tiles).

 

[Submariner]

This is a great addon, I've been waiting for an Ares V for a long time. The launcher has plenty of power, and the EDS and Altair are top notch, too. I tried the Orion and Altair in lunar orbit scenario, and after repositioning my equatorial inclination to 0 with the scenario editor, and performing a DOI, I used LOLA MFD to bring me down to a beautiful, soft landing at tranquillity.

I tried using the PEG autopilot to launch the Ares V, and it worked great until the SRB sep. The roll was quick and accurate, followed by a nice, gentle pitch. But after the SRB sep, the autopilot pitched it down fairly quickly, until it was actually straight down. Stayed that way for a while, and the pitched back up to about horizontal level, and then started yawing violently. I didn't know if that might help you guys at all.

I can't wait until the official release and guidance file, then its off to run a complete constellation mission!

 

[cymrych]

Columbia, Phantom, here it is! A solid, working guidance program. I get SRB sep at 36.4 +/- 0.1, and a burnout that's still about a 0.5km high at 133.8km, but that can be flattened out pretty quickly. Hell, we even get max Q at about the right time! AoA at flame-out is about 5 degrees, nose 11.5 above horizon (and steady for jettison), orbital velocity right at 6000 m/s flat. Should be no sweat picking up the final 1400 m/s for 240 x 240 in the EDS.

But first, I had to make some minor changes.

The thrust curves were great, but I needed to adjust for a couple of things. First, we forgot to change the base SRB thrust, since our percentages in the curve are working up to a maximum of 16.8MN. Second, burntimes. With a slightly varied thrust through ascent, the engines were running long. With a little trial and error, I got them flaming out when we know from the documentation that they ought to. (Speaking of which, anyone know of a way to put a MET or a GET timer on this baby? I HATE having to estimate with just the basic Orbiter clock showing no more precision than 1 second!!)

So, in the Ares V ini file, adjust Booster 2&3 thrust to 16800000, and burnout time to 115.6. Under Stage_1, adjust burnout time to 292.3.

One final change, and I feel like an idiot for having to admit this. I forgot that the proposed RS68B for the core is going to be overclocked to 106%!! So, our thrusts are low. Fortunately, the percentage that you used for the thrust curve is correct, we just need to change the thrust for the core to represent this increase of 6% over standard.

So, in the Ares V ini file, also change the Stage_1 thrust to 22558920.

And that's about it. Here's the guidance program. It's worked like a charm for me so far, even with having to iron out the burn-out altitude a smidge more.

Oh, I should have mentioned ... This guidance file is set up specifically for launching at 92 degrees from the Cape, from the original orientation in the basic Ares V scenario file of 0.0 degrees. I don't know how it'll respond to a different initial heading, but my guess is none too well! Everything in a guidance file is extremely dependant on completing the roll maneuver, and if it takes too much or too little time, the entire rest of the ascent gets out of whack in a hurry. Not that it can't get you to orbit, but your numbers will be way off from mission specs. So be sure to check your ground heading first in the scenario file! Set it to 0.00, add the line directing Orbiter to the guidance file, and have at 'em.

 

[cymrych]

What I've been really trying to do for the last couple of hours is attempting to figure out how to extend this guidance program to the EDS. But since the EDS doesn't "exist" in the scenario until jettisoning from the core, I can't figure out how to direct it to read from a guidance file, short of pausing and saving right after jettison and modifying the scenario file from there. But THAT obviously is not what I'm looking for!

Anybody know of a way?

 

[PhantomCruiser]

I don't think it can be done without some rework of the configuration, such as in the matter of the Ariane6 or something. Maybe if the whole stack being called AresV, staging would be mains, srb's separate when they burnout, 2nd stage would be the EDS and would be controlled by the guidance file, we'd just tweak it to shutdown once the orbit is stable (mostly circular). Writing the guidance would be a piece of cake.

 

[Columbia42]

I had the EDS as part of the .ini file at first but the problem is that it needs to dock with the CEV and multistage2 doesn't have docking capabilities.

 

[PhantomCruiser]

No problem. I think we're pretty close as it is. It's just one of those "wouldn't it be nice if..." things.
As it is now, on separation of the EDS from the Ares, if you full burn and pitch up to 20 degrees, and gradually decrease pitch to 15 (or so), the EDS will circularise orbit at around 215KM alt, with around 48-49% fuel remaining. I've gotten this result over and over again, and it doesn't take any tricky piloting skills. Just a little "feel" needs to be developed, while watching OrbitMFD to know when to decrease pitch angle.
This should be more than enough for an off-plane transfer to the moon using TransX or IMFD, either way, I got it to the moon with no problems.
I'll continue to play around with the guidance file (I've got some ideas...), but I think it's probably good to go as-in (AresVtest10 was my latest).
How soon are we away from a serious release candidate?

 

[cymrych]

You guys try it with those suggested changes I posted with that guidance I posted yet?

Yeah, it'd be nice to continue the guidance to the EDS, but it's no big deal to do it manually. I do pretty much just what Phantom describes. What I usually watch is the time to Apo; if its shrinking, increase angle of attack a hair, if its growing, decrease it a little. The goal of course to have the angle of attack at zero when the apogee is the altitude you want and time to apo is zero.

 

[PhantomCruiser]

I'll try it out when I get home. I'd dump the fairing earlier though. I'm not sure when the "real" thing was to be jettisoned, but I'd lose it earlier just to get rid of the added mass.
I'm pretty sure I can get it to roll quicker, after further study I'm almost positive that I can make it roll as quickly as Shuttle does when she leaves the pad. I just need to get home so I can work it up.

 

[Pablo49]

I have not tried your guidance file yet, but I did see somewhere that the fairing might be dropped right after SRB sep. Not sure how valid that is, but it's not like it's any less accurate than any other guess.

 

[PhantomCruiser]

I was dropping it off at T+165, the altitude right around there is 85Km (last I checked). Is multistage smart enough to change performance based on the loss of mass due to fairing sep? I can run some numbers and see if performance changes depending of when the fairing is dumped.

Ran the guidance file, I like it! Works great.
When the fairings are jettisoned seems pretty inconsequential. I don't know what the "official" line is, but I think it looks better to drop them earlier.

 

[Columbia42]

Yes, multistage does take the mass reduction from fairing sep into account.
BTW, anyone got an answer to my previous question about the surftiles? I'd test it myself but I messed up my textures directory and I'd have to reinstall Orbiter.

 

[PhantomCruiser]

I haven't yet started to tackle surface tiles yet. I do remember a tread about it somewhere though...
I found a bit of information about Easytiler, but it looks as if it may have some issues, or not work any longer...

 

[cymrych]

No clue about surface tiles man, sorry.

I know that if you turn on the flight recorder, you see a teeny tiny drop in mass on the graph when the fairings go. So it's likely that loosing them early would gain a miniscule amount of further deltaV.

Mission profile suggest fairings jettison at 295. In real life, of course, we'd have to worry about heating and the tiny bit of air up their affecting the Altair. Fortunately, we dont really have that concern!

Phantom, let me know if you can get her to spin a little quicker. I'm fresh out of ideas, but I hate the 40ish seconds it takes at present to complete the roll. 2 degrees/second seems really sluggish, but then again, she's not exactly a petite piece of machinery...

---------- Post added at 03:45 AM ---------- Previous post was at 02:11 AM ----------

Hey guys, got an odd little issue. Seems I didn't get all the wrinkles out of the lunar mission out after all.

I launch Ares V, park the EDS no problem. Switch to the I, orbit the Orion no problem. Maneuver a bit, align the planes, no sweat. Set up a sync orbit, ... and Orbiter crashes out when I finally get to within 50km of the parked EDS. Missing meshes, according to the log.

This has happened a lot, and at first I thought it was something I was doing, like trying to accelerate time too much. Or that (for some reason I couldn't possibly think of) it had to do with how much time I let the sim run. So today, I ran a real-time launch; Ares V first, I 90 minutes later, aligned Orion to EDS, set up a 4-lap sync-intersect, was down to about 15 minutes to go ... CTD when EDS was practically within visual range.

Do you think we have a conflict here somewhere? Too many spacecraft3's or something in the scenario? It's goofy, I can't see anything obvious that would cause this reaction. I can run either ship for hours and hours with no issues, but when I bring them into proximity, the system pukes out on me.

Any thoughts?

 

[Columbia42]

As for the CTD problem; to make sure it isn't something wrong with the Ares V rocket, I suggest downloading a different Ares I rocket and see if the same thing happens. (You'll have to modify the scn file a bit.)

 

[cymrych]

Yep, I'm in the process of eliminating stuff one at a time, see if I can't narrow down the where the issue is stemming from. It just sucks that it's so far into the mission before CTD occurs. It'll take a while to test each thing.

But I hadn't thought of trying a different Ares I launcher. I'll give that a go next.

---------- Post added at 08:30 PM ---------- Previous post was at 03:06 PM ----------

So this is weird. It works ... but I have no idea why.

I swapped out francisdrake's Ares I, which I believe he had encorporated into his custom .dll for his CEV-Orion, for the original one provided to him by Simcosmos, which is still in Vinka's Spacecraft(2 or 3, I don't recall).dll.

And somewhat weirdly, it worked. Although I have no idea why, since the Orion that is approaching the EDS stack when I got CTD is exactly the same! Maybe there's something in the coding of francisdrake's .dll that's causing a conflict with the Ares I booster, even though by the time of CTD, it's long since crashed in the ocean somewhere.

So, your Ares V seems stable Columbia. I'm going to sub-out a DG in my test scenario, just to be certain, but my gut tells me that the Ares V is not the culprit here.

I think someone asked about this, but is there some sort of work around for having to jettison the altair in order to dock to it? It's not a big deal, since it seems that when you jettison it from the EDS, it almost immediately docks itself to the EDS, port 1 to port 1. It's just kind of strange, tis all.

Like I say, no big deal. I have to jump in the EDS anyway to hit killrot before docking, so hitting Cntrl-D isn't exactly a lot of extra work.

Man, I'm loving this ship more and more, Columbia! Well done! Glad I could help you out at least a little. Gives me inspiration to maybe try my hand designing something of my own ...

 

[cymrych]

PS: If you try swapping out the original Ares I from simcosmos, you'll have to slightly modify some cfgs for use with francisdrake's latest CEV-Orion (0i.zip). Here's a wordpad cut-n-paste of his post:

 

[Columbia42]

The EDS/Altair docking is the only way I can think of doing it bt if you have another idea feel free to try it.

 

[Pablo49]

Cymrych, that is the work around for the Altair/EDS issue. It's the easiest way to get it to work. And the jettisoning is really just to make Altair it's own ship, instead of just a visual mesh on the EDS. I believe it was mentioned before that the Jupiter Direct addon does a similar technique.

I just launched Francisdrake's Ares I and docked with the EDS just fine, no CTD. Albeit this isn't with your modified lunar mission scenario. This was the Ares V launch, with the the Ares I added to it.

Also, I haven't tried the Ares V for a few betas, and I finally just caught up to the newest, which brought up a question: Do you plan on updating the textures more? Like the main tank isn't very detailed at all, and the white of your fairings don't match the white of the EDS and interstages. (Though, I know you didn't make the fairings, so I can see how that color difference came up.) Not like those are a big deal, but visual improvements would be nice.

 

[Columbia42]

In looking at concept art and animations of the Ares V, I never really saw much detail on the core stage and I'm not much of a texturer so I'm not going to work too hard on it. However if you want to work on better textures I'd greatly appreciate it.