Ares I-X

[mjennings]

Triboelectric is the fancy name for static electricity.

Lightning is a big static electricity discharge caused by charge diffrences between cloud to cloud, the ground, you in the worse case, etc.

Very small static charges less than 3 volts can fry sensitive electronics, the sparks you make/feel on a dry winter day are 3000 volts+ iirc. The shuttle has a good deal of static protection thus why there isn't a constraint for a shuttle launch.

 

[luke strawwalker]

Triboelectric is the fancy name for static electricity.

Lightning is a big static electricity discharge caused by charge diffrences between cloud to cloud, the ground, you in the worse case, etc.

Very small static charges less than 3 volts can fry sensitive electronics, the sparks you make/feel on a dry winter day are 3000 volts+ iirc. The shuttle has a good deal of static protection thus why there isn't a constraint for a shuttle launch.

Yep... maybe tomorrow... hope the weather is better...

Maybe they should put a big wool sweater on it, rub a bunch of balloons against it (I hear there's a guy in Colorado with a bunch for sale cheap!) or get everybody to scuff thier feet on the carpet all the way across the room and then go give it a kiss... :y:

:roll::roll::roll: OL JR

 

[georgegassaway]

I thought the SRB's only had limited thrust control and the SSME's did most of steering. Does the Aries booster have more gimbal action, or is it that the stick just doesn't need as much vectoring for guidance?

No, for the shuttle, the SRB’s have a lot of steering capability.

It would be impossible for the shuttle to steer properly with the SSME’s alone, with the SRB’s attached.

While on the flip side, if the shuttle SSME’s all three shut down, the shuttle stack would still fly under control due to the SRB’s. It would climb to get pretty high and wait for SRB burnout and SRB sep before the orbiter would sep from the tank. Unfortunately in that case a RTLS (Return to Launch Site) would not be possible, so they’d have to set the orbiter to splash in the Atlantic, in a steady automated glide, and the crew would parachute out starting at 10,000 feet.

IIRC, the SRB’s have about 8 degrees of gimbal motion (not sure if that is total or each way), which is less than the gimbal motion of the orbiter SSME’s. But, the SRB’s contribute 2.8 million pounds of thrust EACH (5.6 million total), while the orbiter’s three SSME’s combined are about 1.1 million, so the SRB’s do not need to have as much angular deflection to control the flight as the orbiter’s SSME’s do (The orbiter SSME’s need extra throw to handle post-SRB sep flight with the ET which is still over 75% full at SRB sep. And also needs the maneuvering potential for an RTLS abort maneuver).

Edit - the shuttle SRB gimbal travel is 8 degrees each way from center. Orbiter SSME’s gimbal 8.5 degrees in Yaw, and 10 degrees in Pitch, each way from center.

Now, back to Ares-1, even though it is using the same kind of SRB hardware, and I WILL assume that it has the same potential range of motion as used for the shuttle, I would not assume the guidance software is programmed to allow (or require) the same range of motion as used for a shuttle flight. Or, it could be possible that Ares-1 would have a higher moment of inertia than a shuttle stack does, and might actually need more gimbal throw than a shuttle flight. But I would not assume that just because it is taller, that it has a greater moment of inertia, since what is on top does not weigh THAT much (compared to the SRB), and it also lacks the “side mass” of the ET and orbiter that two SRB's share.

- George Gassaway

 

[luke strawwalker]

Well, it's nearly 1100 Eastern, and they're still waiting on weather... not looking good...

PAO just said they're going to try to pick up the count at 1104 for a launch at 1108... tribo is still red...

Man, after the freighter screw up yesterday, the probe cover sticking on top of the rocket and having to tugged on for 10 minutes or so and finally being ripped off, and the Carnival cruise ship hovering JUST OUTSIDE the denied area waiting for liftoff, and the lousy weather, they've just had a rough go of it... I wish them the best!

Kathy Winters, the weather officer, on the PAO link just said it's still red on the tribo... they're sending the T-38's in... range is clear to at least 11:45, launch window closes at noon Eastern...

Later! OL JR

 

[Boosterdude]

Go Ares, beautiful launch!!!

 

[JAL3]

Wow.

This is the first "live" shot I've been able to see since Apollo 17.

The graininess on the computer screen reminds me of the same on the TV way back when.

 

[Boosterdude]

The steer away from the pad was perfect, no worries with that. The only delays were really just weather. Awesome Job NASA!!!

 

[mjennings]

even with the steer away there was a split second where I thought it was gonna go the wrong way. Pretty lauunch don't forget the replays on nasa tv running now 1144 est

 

[Boosterdude]

even with the steer away there was a split second where I thought it was gonna go the wrong way. Pretty lauunch don't forget the replays on nasa tv running now 1144 est

Yeah, the replay of the camera mounted just above transition looking down is a cool shot. It left in a hurry.

 

[luke strawwalker]

Looked real good... it did look like it drifted closer to the tower than it should have, but it may have been the camera angle and other camera artifacts...

Just watched the replays... It also looked like they induced a tumble in the upperstage simulator at seperation. I don't know if that was intentional or accidental consequence. They put seperation motors to 'pull' the lower stage away from the upperstage, and then fire 'tumble motors' to kick the first stage into an 'end over end' tumble like the shuttle SRB's do, but the tumbling is induced by the angles of the seperation motors on the shuttle stack, not from specifically installed 'tumble motors' like Ares....

Anyway, it was a good flight, and I hope they got the data they needed. I also hope more video comes in-- man those onboard cams broke up A LOT... (somebody send 'em a gum-cam LOL) Would've thought they'd have better antenna coverage than that, or transmitted with more power or something. Oh well. When the picture wasn't broken up, it WAS cool...

SO... now we've managed to repeat the MRBD flight (well, either not as high or as fast or as long; maybe more like a Little Joe flight) so now let's see if they can do it with actual FLIGHT RATED hardware instead of simulators and 'battleship' components...

Later! OL JR

 

[luke strawwalker]

The REAL reason Ares I-X launch was delayed SO MANY TIMES... :y::roll::roll::roll::dark:

Hehehehe... Yall have a good one! OL JR

 

[Boosterdude]

Yeah Luke in some of the shots it did look closer because of the angle. The support arms in the background make it look odd depending on the angle. But a couple of shot angles on Nasa TV show the Ares maneuver away and not even close to the tower.

 

[hedgie6]

Congratulations to everyone at NASA and all the contactors on a successful step on the next stage in the US Space program.

James

:clap:

 

[luke strawwalker]

Yeah Luke in some of the shots it did look closer because of the angle. The support arms in the background make it look odd depending on the angle. But a couple of shot angles on Nasa TV show the Ares maneuver away and not even close to the tower.

I'd still like to see the video from the tower cams... like the shots from the white-room level cam or 'beanie cap' level cam of the shuttle liftoffs...

Surely they still had these cams installed for Ares I-X... I've seen some shots of the 'interstage area' arm to the top of the SRB, which is the same level as the 'beanie cap' of the Shuttle stack (Ares I is roughly twice as tall as the shuttle stack).

I'm waiting for that video... OL JR

 

[brianc]

Edit - the shuttle SRB gimbal travel is 8 degrees each way from center. Orbiter SSME’s gimbal 8.5 degrees in Yaw, and 10 degrees in Pitch, each way from center.

https://www.space.com/common/media/video/player.php?videoRef=SP_091028_ares-roll-control

That video (@ ~0:38) shows the SRB gimbal action. The rest of the
clip is about roll control. And the narrator must be targeting 4th graders
for his demographic... "Can you say 'Reaction Control System?' I
knew you could..."

 

[JStarStar]

I think some of it is that we have never seen an Ares liftoff before, so we don't know how it's "supposed" to look.

Everybody would know instantly if a Shuttle veered unusually close to the tower on liftoff (even by a couple of feet), because those of us who care about rocketry have seen dozens (or hundreds) of shuttle launches, from numerous angles, over the last 27-28 years, while this was the first time we saw the Ares go.

 

[georgegassaway]

As for Ares being close to the tower, it was programmed to swing the tail a little bit towards the tower, to cause the whole vehicle to actually pitch the opposite way to clear the tower (if you want the nose to move right, you have to move the tail to the left).

This was also done with the Saturn-V.

The shuttle does not have to do such a pitch-away-from-tower maneuver because due to the orbiter's SSME engine thrustlines, they cause the shuttle to "crab" away from the pad, in the direction of the "belly" of the orbiter. Watch a good close up side view replay sometime and it is very obvious. Now, the shuttle is not moving directly away from the tower, it is moving away at 90 degrees, but it is definitely moving sideways at launch more than any launch vehicle ever does (on purpose).

Back to Ares today.....

Glad to see that Ares 1X worked.

But it seemed strange that once the SRB separated, that the dummy upper stage went into a tumble too easily and quickly. If that was a real flight with a live upper stage, I would be concerned it would pitch or yaw many degrees before the J-2 engine came up to thrust enough to steer it.

But I have seen some news, not confirmed, by some knowledgeable observers that there seems to be a very good reason why the dummy upper stage started to tumble so relatively quickly.

Apparently, the SRB did not separate cleanly, despite the separation rockets at the base of the SRB ( 8 firing upwards as Retros, and 4 sideways to make the SRB tumble). That would likely be due to the fact that the SRB's do not cleanly shut "off", there is still stuff burning inside which produces some thrust. For the shuttle flights, the SRB's do not sep until the SRB chamber pressures drop to a pre-set value (like 50 PSI). But of course for the shuttle the thrust from the Orbiter SSME's are plenty to push the shuttle onwards (residual thrust in the SRBs is still too low to allow the SRBs to accelerate as much as the shuttle is), and also the SRB's have sideways firing sep motors on the noses that help to push the noses of the SRB's to one side (as well as motors in the aft skirts that also provide a separation vector force).

Interestingly, "re-contact" is an issue that there was concern about before for Ares 1, so apparently they did not fix it. And, "re-contact" is an issue that has plagued one or two new private launch companies in the last couple of years, Space-X's Falcon 1 failed on its third flight when the 1st stage ran into the 2nd stage after stage sep.

As I replay the flight again, that does not seem to be just a random aerodynamic tumble, due to the direction which is very unlikely to be a coincidence. The SRB starts to yaw to its right, SRB front end swinging from left to right, while the dummy upper stage base also swings from left to right. So there had to be some physical contact to make the dummy upper stage tumble in mirrored response to the SRB's tumble. If it was not "re" contact, then it would have to be something equally as bad such as one or more explosive bolts not blowing to let the two drift apart, but being sheared from the side forces (or some other goofy thing like an electrical cable disconnect that hung).

FWIW - check out this Youtube vid showing animation of what the Ares 1X flight would be like. Pay attention at about 50 seconds onwards when the base retro sep motors fire on the SRB and see how today's sep was nothing like that (Actually I question part of the animation since it seems to show the retro-sep motors firing almost to the point of burnout before the upper stage seps, which makes no sense. The upper stage explosive bolts should fire the same instant as the Retro-sep motors, or maybe just a hair after the Retro-Sep motors start to fire).

https://www.youtube.com/watch?v=5U4Zi9xJAcQ

I have been browsing around to try to find any onboard (or ground/sea based) video of the SRB chute deployment and landing. Have not found anything yet. The same sources that mentioned the recontact also say one of the three SRB chutes failed. But that alone is not a big problem (has happened before), it means the SRB landed harder than intended and might be an issue for refurbishing the Aft Skirt (now if two of three chutes failed, that would be a big problem).

OK, found an interesting Youtube vid. Here is one with replays from various angles. In this one, look at SRB burnout starting at about 5:46, and the sep. It seems as though it is already bending apart before the sep motors have finished. But if nothing else you can VERY clearly see how the SRB swings one way and the dummy upper swings the other way, a though semi-hinged from touching. You will notice the significant amount of residual flame (and some thrust) coming from the SRB long after the two have pivoted away from each other, that is not from the sep motors! There is also a replay from one of the onboard cameras, but the camera cuts out RIGHT when the Sep motors fire (Well, I did not see them fire before the video cut out, but I could tell the SRB was burning out, then no signal, then views of tumbling around which seemed to be from a different camera).

https://www.youtube.com/watch?v=4iiuFPgQKbo

There were two onboard cameras. Mostly the downward looking one was shown, camera 1, mounted on the dummy upper stage. But there was one looking up (camera 2), mounted on the SRB. That seems to be the camera that was working after the separation with the dirty lens. I have looked on Youtube but cannot find liftoff thru sep video of Camera 2. Have to figure that if indeed there was "recontact", the video from those cameras would show it. But since the video signals drop out so easily on those things, there might not actually be a recording anywhere. Well, I would hope the managers of this program would have though thru this enough to also have a hard-wired video feed to some Tivo/PVR type device stored in the part of the SRB that was recovered by parachute, so there would be uninterrupted hi-quality video available after retrieval. Heck, even the Saturn program had onboard cameras, but they had to jettison the cameras/film shortly after staging and it was very "iffy" to find them on the ocean's surface (some were found, many were not).

- George Gassaway

 

[jadebox]

But it seemed strange that once the SRB separated, that the dummy upper stage went into a tumble too easily and quickly. If that was a real flight with a live upper stage, I would be concerned it would pitch or yaw many degrees before the J-2 engine came up to thrust enough to steer it.

As I understand it, the tumbling of the second stage wasn't expected. But, it's not a concern because the real Ares first stage will separate at a higher altitude where the air is thinner. Plus, the second stage would fire and its guidance system would be in control.

-- Roger

 

[JStarStar]

Some launch vehicles (the R-7 family and the Titan family) have a vented or open interstage to allow the second stage to come up to thrust and separate from the first stage and thus prevent "re-contact."

The ullage motors on the Saturn V interstage serve the same purpose (also of course to make sure propellants are gravity-seated in the upper-stage tanks).

I wonder if they might design a vented or cage-style interstage for Ares for this purpose.

Of course in LPR model rocketry we have a nearly-identical situation with "gap staging."

 

[NJnike]

I wonder if they might design a vented or cage-style interstage for Ares for this purpose.

Oh I hope not. Because once that happens all you have to do is stick four conical shaped boosters and Ares is going to look like a scaled-up Soyuz.

 

[rockets2000]

Oh I hope not. Because once that happens all you have to do is stick four conical shaped boosters and Ares is going to look like a scaled-up Soyuz.

Perhaps that would remove some of the doubt as to its performance...

 

[rocketguy101]

I wonder if they might design a vented or cage-style interstage for Ares for this purpose.

An early version of Ares-1 did have a cage style interstage...later analysis indicated the bending moment was too high, and they felt it would collapse.

The images I posted came from a 3dsMax model NASA had posted for awhile.

 

[Fred22]

I think the flight went well from what I could see. As the program moves on and the rocket really begins to show its paces then I imagine doubt will begin to fade away Soyuz is great but I think we need to move on
Cheers
fred

 

[JStarStar]

Oh I hope not. Because once that happens all you have to do is stick four conical shaped boosters and Ares is going to look like a scaled-up Soyuz.

I would think it would be a fairly easy matter to strap on some SRB units from the Atlas or Delta boosters and come up with an "Ares III-C" medium-payload vehicle to fill in the gap between the Ares I and Ares V.

Of course, various versions of the Atlas and Delta, as well as the Soyuz, already address that need.

 

[georgegassaway]

Regarding the separation, I've been doing some more web surfing, checking info, and looking at the video again.

When sep occurs, first they fire the "Booster Deceleration Motors" (BDM) in the aft skirt. I like to think of them as "retros" since they face forward.

Then 4/100 of a second ( 0.04 sec) after BDM ignition, the Dummy upper stage would physically disconnect (explosive bolts). There is supposed to be an increasing distance gap between the two, and the dummy upper stage was supposed to continue coasting without going into a tumble so quickly. You never saw Saturn upper stages start to visibly pitch or yaw in the time between stage sep and upper stage motor ignition (there was no "guidance" to keep them straight. Stages will stay straight for awhile due to inertia, as long as nothing abnormal happens like a lower stage ramming into it!). The Saturns had adequate separation motor thrust levels to keep them from hitting each other, and the lower stage thrust had completely ended before staging).

The “tumble" motors (Booster Tumble Motors or BTM's) in the base of the SRB (mounted sideways), fire three seconds after the BDM's.

When I look at the video, here is what I see. The exhaust smoke from the BDM's firing forward, but no distance separation between the SRB and upper stage. Instead, the SRB starts to tumble one way, and the dummy upper starts to tumble the other way, as though they are touching and pivoting away along the point where they are touching, until finally they are no longer touching and many many degrees apart.

And that all happened in three seconds, at which point finally the BTM's in the SRB aft skirt were supposed to fire. I did not see any exhaust or flame from any tumble motors (BTM) from 3 seconds on as scheduled. I do see what MAY be an extra exhaust start at about 1 to 1.5 seconds after the BDM motors start to fire, which might be the BTM's, or it might be related to the flames/exhaust coming from inside of the SRB.

It is pretty strange that just before sep, the SRB exhaust "flame" seemed to go out, then when the BDM's ignited, it seemed as though the flame flared up again from the SRB exhaust. Now, normally with a shuttle SRB sep, there is still visible flame seconds after the SRB's sep, so it actually it was strange the flame had seemingly dropped down to nothing but smoke at sep time (then the flame grew again).

Anyway, it seems like the BTM’s (tumble) may not have fired correctly. But, those were not to blame for the contact, or re-contact, because the BDM’s were SUPPOSED to have sufficient retro-thrust (and SRB thrust dropped to insignificance) that the SRB should not have been in contact with the dummy upper stage from the moment the explosive bolts fired.

Now I wonder if perhaps only some and not all of the BDM’s (retro) motors fired. Or if indeed it was just as “simple” of a rocket science thing that the SRB had more thrust after “burnout” than expected.

FWIW - a web story from August mentioning the potential recontact problem.

https://www.flightglobal.com/articl...ntact-is-ares-biggest-performance-threat.html

- George Gassaway

 

[dixontj93060]

Gerorge,

Thanks for the analysis/commentary. I (and I'm sure others) really appreciate it.

-Tim

 

[luke strawwalker]

Some launch vehicles (the R-7 family and the Titan family) have a vented or open interstage to allow the second stage to come up to thrust and separate from the first stage and thus prevent "re-contact."

The ullage motors on the Saturn V interstage serve the same purpose (also of course to make sure propellants are gravity-seated in the upper-stage tanks).

I wonder if they might design a vented or cage-style interstage for Ares for this purpose.

Of course in LPR model rocketry we have a nearly-identical situation with "gap staging."

Ares I WAS going to use 'fire in the hole' staging (like most of the Russian stuff, and Titan II, etc) when it was going to use the airstart SSME, way back at iteration one of the design... that was back when it had an open "Warren Truss" interstage like the Soyuz...

When they realized airstart SSME wasn't going to happen, and switched to J-2X, they went with an enclosed 'frustum' inverse cone interstage that we see now... OL JR

 

[luke strawwalker]

I would think it would be a fairly easy matter to strap on some SRB units from the Atlas or Delta boosters and come up with an "Ares III-C" medium-payload vehicle to fill in the gap between the Ares I and Ares V.

Of course, various versions of the Atlas and Delta, as well as the Soyuz, already address that need.

Well, strapping GEM boosters onto the sides of the Ares I have been proposed by some folks to increase the performance capabilities of Ares I, but the problem is, it would reduce the 'safety numbers' (which is really more 'imaginary' than real IMHO-- remember when shuttle was deemed by the safety numbers as 'the safest vehicle ever flown' despite not having an escape system??) because of the potential for the strap-on boosters to malfunction, explode, or otherwise cause problems, and because of the additonal staging events of having to have them seperate from the SRB first stage in flight...

Besides, IF they used GEM motors on the side of an SRB, the obvious question would then be "why are we designing this overexpensive underpowered monstrosity when we can use GEM boosters on an existing Delta IV or Atlas V and use it to launch Orion??"

THAT is the question everybody inside wants to avoid at all costs... OL JR

 

[luke strawwalker]

The SRB's do have SOME thrust after burnout-- not a "lot" but when you're talking about over a million pounds of thrust at peak power, just about anything above zero can cause problems. It's sorta like our BP motors when they stage-- the booster motor when it burns through the upper disk of propellant, the burst disk of propellant relieves the pressure inside the case, causing the thrust to drop to 'insignificance', but yet there is STILL burning chunks of propellant flying forward propelled by the hot gases in the motor casing at well over 100 PSI (pressure now relieved by the disk bursting) and there is still a thin burning 'ring' of propellant and maybe some bits of burning propellant still burning clinging to the inner walls of the lower stage engine casing. I have staging photos of fire shooting out both ends of the motor at staging on an Estes Vigilante, a thin residual thrust flame coming out the back of the booster, and a flame shooting out the front of the booster motor from the burst propellant disk, and the beginnings of a feather of flame from the just ignited upperstage engine coming up to pressure, with about an inch or two of seperation between both the stages. The SRB behaves somewhat similarly, but since there is no "burst disk" or relief ports like on the ICBM's or the Pershing II's to terminate thrust by allowing the residual pressurized gas to shoot out the forward end of the booster, it's all forced to go out the nozzle end, generating a small amount of thrust. There are probably a few thin 'skins' or thin chunks of burning propellant left inside the booster casing stuck to the walls of the casing, burning away, which contribute to this thrust and to the residual flames, smoke, and sparks which continue to blow out the nozzle after 'burnout' for a considerable time after the SRB is jettisoned, or in this case, after staging.

I certainly hope that they instrumented to measure this effect, and will instrument the remaining shuttle flight boosters as well to sense this 'residual thrust' after burnout, because it's going to be important for the safety of Ares I staging. Recontact is a VERY bad thing!

There might also be some tiny timing errors related to the seperation sequence that might need tweaking-- maybe slightly more powerful 'retros' to counteract the 'residual thrust' of the SRB first stage, and a little more 'seperation time' to allow the upperstage to coast a bit farther away before ignition of the 'tumble motors' on the back of the SRB, so the two have plenty of clearance before the first stage is induced to tumble. I should see no reason that the tumble inducement is time-critical-- after all, the thing is still continuing to coast upward after burnout, just as our rockets do... You want to start deceleration, yes, but in air that thin (you're above most of the atmosphere at that point, and the REAL Ares I will stage even higher in even thinner air) tumbling isn't going to slow you down that much anyway, until you start descending into thinner air...

As is, for Ares I-X it's a moot point, because there won't be another, but I DO hope they get good data back and can reconstruct the dynamics of the seperation, because it could prove quite useful not only for Ares I, but for other vehicles as well... OL JR

 

[mjennings]

There was a very large dent on the bottom of the booster, space.com and spaceflightnow.com had some cool underwater pictures of the dent. The retrieval ships were due back this morning so hopefully they'll say more, if it was due to the 2 parachute landing or something else