Ares 1X Launch results
Derek Lyons
or not it was 100% sucessful. No word on splashdown.
D.
--
Touch-twice life. Eat. Drink. Laugh.
http://derekl1963.livejournal.com/
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Derek Lyons
>Lots of self congratulation going on - even though no word of whether
>or not it was 100% sucessful. No word on splashdown.
>
>D.
And of couse just as I hit 'send' word came in that the recovery
vessels confirm the stage has been sighted on the surface and intact.
Greg D. Moore (Strider)
news:4ae8665a....@news.supernews.com...
> Lots of self congratulation going on - even though no word of whether
> or not it was 100% sucessful. No word on splashdown.
>
Definitely a lot of self-congratulations. Let's see what's actually
learned. Other than tribo rule sticks around.
If so, that's going to make Ares-I a really sucky launch vehicle.
--
Greg Moore
Ask me about lily, an RPI based CMC.
Cyberia
"Greg D. Moore (Strider)" <mooregr_d...@greenms.com> wrote in message
news:H6idnfROso3Z8nXX...@earthlink.com...
> "Derek Lyons" <fair...@gmail.com> wrote in message
> news:4ae8665a....@news.supernews.com...
>> Lots of self congratulation going on - even though no word of whether
>> or not it was 100% sucessful. No word on splashdown.
>>
>
> Definitely a lot of self-congratulations. Let's see what's actually
> learned. Other than tribo rule sticks around.
>
> If so, that's going to make Ares-I a really sucky launch vehicle.
>
It looked to me like the business end of the first stage came *awfully*
close to the various service arms of the pad. I read the SRM was supposed to
gimbal such that it flew away from the pad. The video looks as though the
opposite took place. The aft end approached the pad.
Derek Lyons
>"Derek Lyons" <fair...@gmail.com> wrote in message
>news:4ae8665a....@news.supernews.com...
>> Lots of self congratulation going on - even though no word of whether
>> or not it was 100% sucessful. No word on splashdown.
>
>Definitely a lot of self-congratulations. Let's see what's actually
>learned. Other than tribo rule sticks around.
>
>If so, that's going to make Ares-I a really sucky launch vehicle.
AIUI: The actual Ares-I will not be as constrained - the
vulnerability to tribo can be vastly mitigated but NASA elected not to
spend the money to do so for this unique one-off launch. You have to
specially certify the coatings used on the vehicle and the electrical
bonding between stages and components (to prevent currents flowing
along the skin and arcing amongst vehicle components).
"Cyberia" <n3...@comcast.net> wrote:
>It looked to me like the business end of the first stage came *awfully*
>close to the various service arms of the pad. I read the SRM was supposed to
>gimbal such that it flew away from the pad. The video looks as though the
>opposite took place. The aft end approached the pad.
The SRM gimbals to direct the vehicles flight path away from the
tower, not to direct the vehicle away from the tower per se.
If you look at the video frame-by-frame, you can plainly see the
exhaust cloud behind the service arm - the closeness of approach was a
trick of perspective.
Greg D. Moore (Strider)
> "Greg D. Moore \(Strider\)" <mooregr_d...@greenms.com> wrote:
>
>>"Derek Lyons" <fair...@gmail.com> wrote in message
>>news:4ae8665a....@news.supernews.com...
>>> Lots of self congratulation going on - even though no word of whether
>>> or not it was 100% sucessful. No word on splashdown.
>>
>>Definitely a lot of self-congratulations. Let's see what's actually
>>learned. Other than tribo rule sticks around.
>>
>>If so, that's going to make Ares-I a really sucky launch vehicle.
>
> AIUI: The actual Ares-I will not be as constrained - the
> vulnerability to tribo can be vastly mitigated but NASA elected not to
> spend the money to do so for this unique one-off launch. You have to
> specially certify the coatings used on the vehicle and the electrical
> bonding between stages and components (to prevent currents flowing
> along the skin and arcing amongst vehicle components).
>
That makes a bit more sense. For a test vehicle, I can see not spending the
money on that.
>
> D.
Jeff Findley
> or not it was 100% sucessful. No word on splashdown.
The press conference following is giving some indication that the first
stage did recontact the upper stage simulator after separation, but they're
not outright admitting it yet. This is a problem with SRB's. The thrust
doesn't stop cleanly like a liquid engine. It slowly tails off. And with
the hammer head design of the vehicle, getting a clean separation will be a
challenge.
Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon
Cyberia
"Jeff Findley" <jeff.f...@ugs.nojunk.com> wrote in message
news:d4060$4ae88561$927a2cda$21...@FUSE.NET...
>
> "Derek Lyons" <fair...@gmail.com> wrote in message
> news:4ae8665a....@news.supernews.com...
>> Lots of self congratulation going on - even though no word of whether
>> or not it was 100% sucessful. No word on splashdown.
>
> The press conference following is giving some indication that the first
> stage did recontact the upper stage simulator after separation, but
> they're not outright admitting it yet. This is a problem with SRB's. The
> thrust doesn't stop cleanly like a liquid engine. It slowly tails off.
> And with the hammer head design of the vehicle, getting a clean separation
> will be a challenge.
I guess that explains the counter-yaw rotation of the second stage at
separation? I know the second stage was unguided, but the sudden yaw seemed
to be a direct consequence of the induced tumble of the first stage, rather
than a random action.
Cyberia
> "Cyberia" <n3...@comcast.net> wrote:
>
>>It looked to me like the business end of the first stage came *awfully*
>>close to the various service arms of the pad. I read the SRM was supposed
>>to
>>gimbal such that it flew away from the pad. The video looks as though the
>>opposite took place. The aft end approached the pad.
>
> The SRM gimbals to direct the vehicles flight path away from the
> tower, not to direct the vehicle away from the tower per se.
>
> If you look at the video frame-by-frame, you can plainly see the
> exhaust cloud behind the service arm - the closeness of approach was a
> trick of perspective.
I'm not convinced. I don't know what video you are watching frame-by-frame,
but if you examine the replays you will see from several angles that the aft
end approaches the tower, and does not appear to deviate significantly in
any other direction *but* towards the tower. Perhaps this was intentional so
as to get the nose moving away from it, but in practice it appears to me
that it was the wrong way to go. Better to get the ass end away, cause the
nose and mid-section are already clear at this point.
I hope there is on-board video from vehicle cameras 1 & 2 that do not show
the breakup at liftoff that the downlinked ones did. Then this will perhaps
be more clearly determined.
Derek Lyons
>
>"Derek Lyons" <fair...@gmail.com> wrote in message
>news:4ae879ee....@news.supernews.com...
>> "Cyberia" <n3...@comcast.net> wrote:
>>
>>>It looked to me like the business end of the first stage came *awfully*
>>>close to the various service arms of the pad. I read the SRM was supposed
>>>to
>>>gimbal such that it flew away from the pad. The video looks as though the
>>>opposite took place. The aft end approached the pad.
>>
>> The SRM gimbals to direct the vehicles flight path away from the
>> tower, not to direct the vehicle away from the tower per se.
>>
>> If you look at the video frame-by-frame, you can plainly see the
>> exhaust cloud behind the service arm - the closeness of approach was a
>> trick of perspective.
>
>I'm not convinced. I don't know what video you are watching frame-by-frame,
NASA's VAB camera I believe.
>but if you examine the replays you will see from several angles that the aft
>end approaches the tower, and does not appear to deviate significantly in
>any other direction *but* towards the tower. Perhaps this was intentional so
>as to get the nose moving away from it, but in practice it appears to me
>that it was the wrong way to go. Better to get the ass end away, cause the
>nose and mid-section are already clear at this point.
If you steer the tail away from the tower, you're steering the
midsection and nose *towards* the tower. Hence, it's better to steer
the tail towards in order to direct the flight path away and onto the
proper trajectory.
Derek Lyons
>
>"Derek Lyons" <fair...@gmail.com> wrote in message
>news:4ae8665a....@news.supernews.com...
>> Lots of self congratulation going on - even though no word of whether
>> or not it was 100% sucessful. No word on splashdown.
>
>The press conference following is giving some indication that the first
>stage did recontact the upper stage simulator after separation, but they're
>not outright admitting it yet. This is a problem with SRB's.
It's not an insoluble one though. Polaris A1 had serious recontact
problems between the (thrust terminated) second stage and the warhead.
It's a matter of getting the timing right.
>The thrust doesn't stop cleanly like a liquid engine. It slowly tails
>off.
Liquid engines doesn't stop cleanly either - they tail off as
propellant in the pumps and lines vent into the engine bell. This is
what caused the failure of the third flight of Falcon I.
ISTR seeing a film from an early Thor launch where the booster
recontacted the payload after seperation as well.
Greg D. Moore (Strider)
> "Jeff Findley" <jeff.f...@ugs.nojunk.com> wrote:
>
>>
>>"Derek Lyons" <fair...@gmail.com> wrote in message
>>news:4ae8665a....@news.supernews.com...
>>> Lots of self congratulation going on - even though no word of whether
>>> or not it was 100% sucessful. No word on splashdown.
>>
>>The press conference following is giving some indication that the first
>>stage did recontact the upper stage simulator after separation, but
>>they're
>>not outright admitting it yet. This is a problem with SRB's.
>
> It's not an insoluble one though. Polaris A1 had serious recontact
> problems between the (thrust terminated) second stage and the warhead.
> It's a matter of getting the timing right.
>
An interesting question will be how the timing and other factors change with
a full 5-segment SRB.
Jeff Findley
> An interesting question will be how the timing and other factors change
> with a full 5-segment SRB.
There will need to be real Ares I test flights to prove that this concept is
going to work. Hopefully they'll be unmanned test flights because a first
stage separation like we saw with Ares I-X would most definitely trigger the
launch escape system for Orion, which most certainly carries risks of its
own.
Derek Lyons
>"Derek Lyons" <fair...@gmail.com> wrote in message
>news:4aeb8c0c....@news.supernews.com...
>> "Jeff Findley" <jeff.f...@ugs.nojunk.com> wrote:
>>
>>>The press conference following is giving some indication that the first
>>>stage did recontact the upper stage simulator after separation, but
>>>they're not outright admitting it yet. This is a problem with SRB's.
>>
>> It's not an insoluble one though. Polaris A1 had serious recontact
>> problems between the (thrust terminated) second stage and the warhead.
>> It's a matter of getting the timing right.
>>
>
>An interesting question will be how the timing and other factors change with
>a full 5-segment SRB.
Yep. And this is also exactly why you fly test flights.
John Doe
The thrust
> doesn't stop cleanly like a liquid engine. It slowly tails off. And with
> the hammer head design of the vehicle, getting a clean separation will be a
> challenge.
Should they actually launch a real vehicle, wouldn't the second stage
ignite at the same time as separation to ensure it doesn't start to
thumble and lose its orientation and also to ensure it doesn't
collide/recontact with the first stage ?
For this prototype test flight, was it normal that the fake second stage
immediatly lost its attitude and started to thumble at separation
(aka: was there still enough air resistance to cause that) ?
Once there is a real second stage, would its mass be significantly
higher than the fake one and give it more time in the proper attitude
before air resistance would start to cause it to thumble ?
John Doe
> If you steer the tail away from the tower, you're steering the
> midsection and nose *towards* the tower. Hence, it's better to steer
> the tail towards in order to direct the flight path away and onto the
> proper trajectory.
Where was the SRB in the Ares1X positioned relative to the 2 SRBs used
in shuttle ? Was it positioned at the same location as one of the
Shuttle SRBs, was it positioned where the shuttle SSMEs would have been ?
If the Shuttle SRBs had no problems clearing the tower without touching
it, why would this glorified firecracker have problems since it is much
smaller/thinner and thus should have far more clearance ?
Derek Lyons
It doesn't have more clearance - it has the same clearance as it was
mounted over the LH SRB hole.
Jeff Findley
> "Greg D. Moore \(Strider\)" <mooregr_d...@greenms.com> wrote:
>
>>"Derek Lyons" <fair...@gmail.com> wrote in message
>>news:4aeb8c0c....@news.supernews.com...
>>> "Jeff Findley" <jeff.f...@ugs.nojunk.com> wrote:
>>>
>>>>The press conference following is giving some indication that the first
>>>>stage did recontact the upper stage simulator after separation, but
>>>>they're not outright admitting it yet. This is a problem with SRB's.
>>>
>>> It's not an insoluble one though. Polaris A1 had serious recontact
>>> problems between the (thrust terminated) second stage and the warhead.
>>> It's a matter of getting the timing right.
>>>
>>
>>An interesting question will be how the timing and other factors change
>>with
>>a full 5-segment SRB.
>
> Yep. And this is also exactly why you fly test flights.
And yet there was little sympathy by you for Falcon I's initial flight
failures even though they clearly learned from them and ultimately were
successful in achieving orbit.
I suppose you have more sympathy for NASA because they deliberately set the
"official goals" very low, allowing them to claim success even in the face
of an obvious failure? Obviously the PAO has been taking lessons from
Montgomery Scott. ;-)
Jeff Findley
"John Doe" <jd...@doe.org> wrote in message
news:0096c30c$0$27961$c3e...@news.astraweb.com...
> Jeff Findley wrote:
> The thrust
>> doesn't stop cleanly like a liquid engine. It slowly tails off. And
>> with
>> the hammer head design of the vehicle, getting a clean separation will be
>> a
>> challenge.
>
> Should they actually launch a real vehicle, wouldn't the second stage
> ignite at the same time as separation to ensure it doesn't start to
> thumble and lose its orientation and also to ensure it doesn't
> collide/recontact with the first stage ?
Possibly, but US upper stages tend to be lit after a clean separation. On
top of that Ares I's SRB first stage is to be recovered and reused, so I'm
not sure firing the upper stage engine essentially on top of the SRB would
be advisable.
> For this prototype test flight, was it normal that the fake second stage
> immediatly lost its attitude and started to thumble at separation
> (aka: was there still enough air resistance to cause that) ?
>
> Once there is a real second stage, would its mass be significantly
> higher than the fake one and give it more time in the proper attitude
> before air resistance would start to cause it to thumble ?
The simulated upper stage had similar mass and inertia properties similar to
a fueled upper stage, so the deceleration caused by air drag would be
similar to a real stage. Plus, separation was pretty high up, so air drag
wouldn't be that high to begin with. I'd imagine the big problem here is
the thrust of the SRB didn't fall off as quickly as NASA's "worst case"
prediction, which is what was used to set the timing of the separation
events.
Derek Lyons
>
>"Derek Lyons" <fair...@gmail.com> wrote in message
>news:4ae9a10c....@news.supernews.com...
>> "Greg D. Moore \(Strider\)" <mooregr_d...@greenms.com> wrote:
>>
>>>"Derek Lyons" <fair...@gmail.com> wrote in message
>>>news:4aeb8c0c....@news.supernews.com...
>>>> "Jeff Findley" <jeff.f...@ugs.nojunk.com> wrote:
>>>>
>>>>>The press conference following is giving some indication that the first
>>>>>stage did recontact the upper stage simulator after separation, but
>>>>>they're not outright admitting it yet. This is a problem with SRB's.
>>>>
>>>> It's not an insoluble one though. Polaris A1 had serious recontact
>>>> problems between the (thrust terminated) second stage and the warhead.
>>>> It's a matter of getting the timing right.
>>>>
>>>
>>>An interesting question will be how the timing and other factors change
>>>with a full 5-segment SRB.
>>
>> Yep. And this is also exactly why you fly test flights.
>
>And yet there was little sympathy by you for Falcon I's initial flight
>failures even though they clearly learned from them and ultimately were
>successful in achieving orbit.
I had little sympathy for the first failure because it was a stupid
dipshit failure. The later failures I didn't mention sympathy one way
or another - I only seemed unsympathetic by comparison because I
wasn't cheering my head off at accomplishing nothing like pretty much
everyone else. Pointing out the plain fact that a vehicle designed to
reach orbit didn't actually do so, regardless of whatever else it
achieved, places you firmly in the detractor camp around these parts.
>I suppose you have more sympathy for NASA because they deliberately set the
>"official goals" very low, allowing them to claim success even in the face
>of an obvious failure? Obviously the PAO has been taking lessons from
>Montgomery Scott. ;-)
I don't have any particular sympathy for NASA. It's the same
situation as the Falcon I test series - pointing out facts like liquid
engines not tailing off cleanly and that solid rocket recontact is a
solvable problem is neither sympathetic or unsympathetic. It's merely
unflinching willingness to address facts as facts without spin. I
don't always suceed, but intellectual honesty and integrity is a goal
I strive mightily towards.
Derek Lyons
>I'd imagine the big problem here is the thrust of the SRB didn't fall
>off as quickly as NASA's "worst case" prediction, which is what was
>used to set the timing of the separation events.
Myself, I'd assume that NASA used acceleration and chamber pressure
data to determine timing of BDM firing. That's how they monitor SRB
performance on the Shuttle, and I see no reason to assume a priori
that the Ares solid motor would be different. (The solid fueled
missiles with which I am familiar use acceleration to time non thrust
terminated separation events.)
Further, given the dangers of asymmetrical thrust tailoff on a Shuttle
flight it's reasonable to assume that NASA and ATK are quite familiar
with the formulation, mixing. and casting procedures needed to closely
control thrust tailoff. (And asymmetrical or unexpected tailoff
performance has never to my knowledge been experienced inflight.) In
addition, with the large number of SRM's and RSRM's ground tested or
flown in the Shuttle program, it's equally reasonable to assume that
NASA is well familiar with the thrust termination characteristics of
these motors and that the Ares flight software and hardware would be
designed with this performance in mind.
That's not to say that a level of tailoff that is out of family is
impossible - only that it seems improbable at first glance. I'd be
very, very, careful about jumping to that conclusion.
I've been reviewing some NASA videos on the web, and they all show
seperation/BDM firing preceding BTM firing and stage starting to
tumble by a second or two. This is confirmed in the press kit which
shows BDM firing at T+124 and BTM firing at T+127. (The launch
timeline linked below shows different absolute times by a second or
so, but the same three second delay.) Also shown in those videos, the
first stage tumbles on a plane at 90 degrees to the BDM packages,
confirmed by the diagram in the flight test plan linked below.
But the flight video shows something very different... it shows
seperation and BDM firing almost simultaneously with what appears to
be BTM firing and the initiation of tumbling. (Assuming A: BTM firing
is visible, and B: the BTM's fired in the first place.) It also
seems, but it's hard to tell, that the booster was tumbling in the
wrong plane.
I'm starting to suspect there's something more going on here than just
a timing issue with thrust tailoff.
Press kit:
http://spaceflightnow.com/ares1x/presskit.pdf
Launch Timeline:
http://spaceflightnow.com/ares1x/091022launchtimeline.html
Flight Test Plan:
http://www.scribd.com/doc/17213945/NASA-Ares-IX-Flight-Test-plans
Brian Thorn
<mooregr_d...@greenms.com> wrote:
>> AIUI: The actual Ares-I will not be as constrained - the
>> vulnerability to tribo can be vastly mitigated but NASA elected not to
>> spend the money to do so for this unique one-off launch. You have to
>> specially certify the coatings used on the vehicle and the electrical
>> bonding between stages and components (to prevent currents flowing
>> along the skin and arcing amongst vehicle components).
>That makes a bit more sense. For a test vehicle, I can see not spending the
>money on that.
And even then, it was only an issue because the USAF got the willies
about the thing, and thought it would shake itself to pieces, crash
into Patrick AFB's Officers Club, spiral out toward Disney World, or
some such disastrous turn of events. So they definitely demanded that
the destruct signal could get through, and therefore enforced the
little-known, seldom-used "triboelectrification clause".
I'm not Ares I's biggest fan, but the detractors were starting to spew
so much bullshit ("it's so long and skinny it will be
uncontrollable!", "it will shake itself to pieces and even the Range
Safety command system will be toast!", "the wind will blow it into the
tower!" "It's Satan Incarnate!") about it that hip-high boots were
needed.
And that, um, exciting seperation? So much for that ever-popular "This
test flight is useless!" argument.
Brian
Brian Thorn
>> If you steer the tail away from the tower, you're steering the
>> midsection and nose *towards* the tower. Hence, it's better to steer
>> the tail towards in order to direct the flight path away and onto the
>> proper trajectory.
>
>Where was the SRB in the Ares1X positioned relative to the 2 SRBs used
>in shuttle ? Was it positioned at the same location as one of the
>Shuttle SRBs, was it positioned where the shuttle SSMEs would have been ?
It was on the inboard SRB mount of the MLP, closest to the tower.
The Tower Avoidance Maneuver didn't push the nozzle-end toward the
tower, it just leaned the entire rocket several degrees away from the
tower, which made the expanding plume appear to move toward the tower
more rapidly than had it gone straight up. Very exciting, to say the
least. But look at Saturn V launch footage some time... the avoidance
maneuver is very visible there, too.
Here's Apollo 15. Compare the Saturn to the Tower.
http://www.hq.nasa.gov/office/pao/History/alsj/a15/ap15-liftoff2-noID.jpg
Brian
Jorge R. Frank
> "John Doe" <jd...@doe.org> wrote in message
> news:0096c30c$0$27961$c3e...@news.astraweb.com...
>> Jeff Findley wrote:
>> The thrust
>>> doesn't stop cleanly like a liquid engine. It slowly tails off. And
>>> with
>>> the hammer head design of the vehicle, getting a clean separation will be
>>> a
>>> challenge.
>> Should they actually launch a real vehicle, wouldn't the second stage
>> ignite at the same time as separation to ensure it doesn't start to
>> thumble and lose its orientation and also to ensure it doesn't
>> collide/recontact with the first stage ?
>
> Possibly, but US upper stages tend to be lit after a clean separation. On
> top of that Ares I's SRB first stage is to be recovered and reused, so I'm
> not sure firing the upper stage engine essentially on top of the SRB would
> be advisable.
Probably would not result in more damage than the SRB does to its own
bottom end due to plume recirculation.
The real upper stage will also have ullage motors firing before the J-2X
to settle the propellants and, not coincidentally, to increase the
separation rate.
>> For this prototype test flight, was it normal that the fake second stage
>> immediatly lost its attitude and started to thumble at separation
>> (aka: was there still enough air resistance to cause that) ?
>>
>> Once there is a real second stage, would its mass be significantly
>> higher than the fake one and give it more time in the proper attitude
>> before air resistance would start to cause it to thumble ?
>
> The simulated upper stage had similar mass and inertia properties similar to
> a fueled upper stage, so the deceleration caused by air drag would be
> similar to a real stage.
No, the real stage will separate at a higher altitude due to Ares I
having a five-segment SRB vs the four-segment SRB of Ares I-X. The air
density, and therefore the drag, will be far lower even though the upper
stage mass properties are similar.
Greg D. Moore (Strider)
news:1vqhe559b36cfoaq4...@4ax.com...
>
> And even then, it was only an issue because the USAF got the willies
> about the thing, and thought it would shake itself to pieces, crash
> into Patrick AFB's Officers Club, spiral out toward Disney World, or
> some such disastrous turn of events. So they definitely demanded that
> the destruct signal could get through, and therefore enforced the
> little-known, seldom-used "triboelectrification clause".
>
> I'm not Ares I's biggest fan, but the detractors were starting to spew
> so much bullshit ("it's so long and skinny it will be
> uncontrollable!", "it will shake itself to pieces and even the Range
> Safety command system will be toast!",
Well that one was from the Range Safety folks themselves.
> "the wind will blow it into the
> tower!" "It's Satan Incarnate!") about it that hip-high boots were
> needed.
>
> And that, um, exciting seperation? So much for that ever-popular "This
> test flight is useless!" argument.
Umm, I'm not sure it belays that argument. I mean we have a system that
doesn't fully model the actual thing and very likely wouldn't happen in the
real system.
So it might be a case of a problem being found that isn't really a problem.
So, I'm still not sold on the usefulness of this test.
>
> Brian
John Doe
Shuttle, Arianne have SRBs that are side mounted and can detach while a
main engine can push the rest of the vehicle ahead (reducing separation
issues). Soyuz also sheds its side mounted liquid engines while the main
engines can continue to push the stack ahead.
In the case of other "payload on a stick" rockets such as Saturn5, did
the main engine bring the upper stages to higher altitude where air
resistance was not an issue ? (compared to what is planned for Ares1)
Derek Lyons
>And that, um, exciting seperation? So much for that ever-popular "This
>test flight is useless!" argument.
Other than the seperation being almost nothing like the seperation in
an actual Ares I, this was a valuable discovery.
Or not.
Cyberia
> The Tower Avoidance Maneuver didn't push the nozzle-end toward the
> tower, it just leaned the entire rocket several degrees away from the
> tower, which made the expanding plume appear to move toward the tower
> more rapidly than had it gone straight up. Very exciting, to say the
> least.
Surely you don't think it possible to gimbal the RSRM nozzle and cause the
nose to yaw immediately away from the tower while the aft end comes no
closer to it? If so you need to watch the replays more closely. Look at (for
example) the DLTR-3 view. This view is nearly perfect for observing the
distance between the tower and any part of the airframe as it ascends.
Before ignition, the skirt of the RSRM is just visible peeking around the
right edge of the port-side tail service mast of the MLP. The entire top
third of the rocket (more than a third, it seems) is already clear of the
tower even before launch.
By the time the skirt is midway up the tower it has moved well to the left
of this point. I've watched this view many times, and the motion of the
rocket's tail towards the tower is quite pronounced and unquaetionable.
There is probably plenty of clearance despite this motion, given that the
various service arms are rotated out to the sides. It still looks to me,
however, that gimballing the RSRM motor so that the aft end of the rocket
moves *away* from the tower rather than toward would give much more
clearance. The rocket could end up flying over the tower but all parts of
its airframe would have more clearance from that structure on the way up.
Perhaps doing so would cause more plume damage to be imposed as the rocket
overflies the tower. I had not considered this before, surely this must
figure into the decision to "fly away".
Brian Thorn
>Is Ares1X the first rocket where the main engine consists only of an SRB ?
Nope. Scout, Pegasus, Taurus, Athena...
Brian
John Doe
The rocket has an immediate slant (aft towards tower, tip towards the
water tank in that view) as soon as it was let go from the launch
platform. That slant was maintained until well above the structures, at
which point, the rocket initiated its ascent attitude with a greater slant.
Shouldn't the rocket have gone straight up until well clear of the
tower, at which point it begins to steer to the attitude needed to go
up/east ?
From my armchair point of view, it looks like a catastrophic failure
that didn't result in a catastrophy. Obviously NASA isn't going to
discuss this publically.
Is there a valid reason to actually program that slant as soon as the
bolts keeping the SRB on the launch platform have fired ?
Also, I have a feeling that conspiracy theorists will question why the
on-board cameras blanked out at launch (not showing the immediate slant
of the vehicle) and during separation (not showing the not-so-clean
separation).
During the original video, they spent a fair about of time showing some
telemetry guy in front of a rack, relating various data he was seeing on
a console. Didn't he , at one point, indicate he had lost a telemetry
feed ?
Has there been any information on the vibration nevironment and whether
it might have been responsible for such losses ?
Brian Gaff
launch, 'we learn even more when things do not go right'
Brian
--
Brian Gaff - bri...@blueyonder.co.uk
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"Derek Lyons" <fair...@gmail.com> wrote in message
news:4ae8665a....@news.supernews.com...
> Lots of self congratulation going on - even though no word of whether
> or not it was 100% sucessful. No word on splashdown.
>
Brian Gaff
drift. It is probably the case that low speed performance is in need of some
tweaking. This should be sortable, but more to the point here, what are the
vibrations like atop a solid only system with no built in decoupling as the
Shuttle has.
Brian
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"Cyberia" <n3...@comcast.net> wrote in message
news:q6ydnY7vVaI26XXX...@giganews.com...
>
> "Greg D. Moore (Strider)" <mooregr_d...@greenms.com> wrote in
> message news:H6idnfROso3Z8nXX...@earthlink.com...
>> "Derek Lyons" <fair...@gmail.com> wrote in message
>> news:4ae8665a....@news.supernews.com...
>>> Lots of self congratulation going on - even though no word of whether
>>> or not it was 100% sucessful. No word on splashdown.
>>>
>>
>> Definitely a lot of self-congratulations. Let's see what's actually
>> learned. Other than tribo rule sticks around.
>>
>> If so, that's going to make Ares-I a really sucky launch vehicle.
Jeff Findley
> On Thu, 29 Oct 2009 00:20:33 -0400, John Doe <jd...@doe.org> wrote:
>
>>Is Ares1X the first rocket where the main engine consists only of an SRB ?
>
> Nope. Scout, Pegasus, Taurus, Athena...
Most launchers (and ICBM's) that I'm aware of with a solid only first stage
have a solid second stage as well. As far as I know, Ares I is the first
big launcher where the first stage is solid and the upper stage is liquid.
Plus Ares I is pretty tall and skinny, even with the hammer head upper
stage. It's been an odd-ball design from day one.
Jeff Findley
> Brian Thorn <btho...@suddenlink.net> wrote:
>
>>And that, um, exciting seperation? So much for that ever-popular "This
>>test flight is useless!" argument.
>
> Other than the seperation being almost nothing like the seperation in
> an actual Ares I, this was a valuable discovery.
>
> Or not.
It's hard to tell isn't it? Since they didn't use a five segment SRB for
this flight, the altitude and speed of the separation wouldn't be the same.
And as Jorge pointed out, the upper stage simulator didn't have any
separation/ullage motors of its own either. This whole Ares I-X flight just
doesn't represent the Ares I hardware closely enough to draw meaningful
conclusions without a whole lot of analysis, which will then have to be
validated by a real Ares I test flight.
So, was the cost of this Ares I-X test flight worth it in terms of the data
gathered?
Jorge R. Frank
>
> There is probably plenty of clearance despite this motion, given that the
> various service arms are rotated out to the sides. It still looks to me,
> however, that gimballing the RSRM motor so that the aft end of the rocket
> moves *away* from the tower rather than toward would give much more
> clearance. The rocket could end up flying over the tower but all parts of
> its airframe would have more clearance from that structure on the way up.
Not in worst-case allowable winds.
Saturn V did the same thing as Ares.
Brian Thorn
<jeff.f...@ugs.nojunk.com> wrote:
>>>Is Ares1X the first rocket where the main engine consists only of an SRB ?
>>
>> Nope. Scout, Pegasus, Taurus, Athena...
>
>Most launchers (and ICBM's) that I'm aware of with a solid only first stage
>have a solid second stage as well. As far as I know, Ares I is the first
>big launcher where the first stage is solid and the upper stage is liquid.
Nope. India's PSLV.
Brian
Derek Lyons
>There is probably plenty of clearance despite this motion, given that the
>various service arms are rotated out to the sides. It still looks to me,
>however, that gimballing the RSRM motor so that the aft end of the rocket
>moves *away* from the tower rather than toward would give much more
>clearance. The rocket could end up flying over the tower but all parts of
>its airframe would have more clearance from that structure on the way up.
Not only does that maneuver place the entire length of the booster at
risk, it also means thrusting *away* from your desired flights path
(which means taking a payload/performance hit).
This alone means you planned manuver is a very bad idea based on
assumptions shown to be incorrect.
And if that wasn't bad enough - a flight path towards and over the
tower *places the booster on a trajectory leading inland towards
populated areas*.
Which isn't happening.
Derek Lyons
Polaris, Posiedon, Trident, Minuteman, Peacekeeper...
Then a whole raft of one-offs and weirdo's like the X-17, Little Joe,
Little Joe II...
Derek Lyons
>Shouldn't the rocket have gone straight up until well clear of the
>tower, at which point it begins to steer to the attitude needed to go
>up/east ?
No. That leaves it vulnerable to onshore winds.
>From my armchair point of view, it looks like a catastrophic failure
>that didn't result in a catastrophy. Obviously NASA isn't going to
>discuss this publically.
As always, you need to either take fewer drugs or the correct dosage
of your prescribed medications.
>Is there a valid reason to actually program that slant as soon as the
>bolts keeping the SRB on the launch platform have fired ?
Yes, to avoid having the booster be blown into the FSS or RSS.
>During the original video, they spent a fair about of time showing some
>telemetry guy in front of a rack, relating various data he was seeing on
>a console. Didn't he , at one point, indicate he had lost a telemetry
>feed ?
They showed him because there wasn't anything else to show at that
point. Loss of telemetry feed was expected as the vehicle went below
the Cape's radio horizon.
Derek Lyons
>
>"Brian Thorn" <btho...@suddenlink.net> wrote in message
>news:dp9ie550p0l06jp46...@4ax.com...
>> On Thu, 29 Oct 2009 00:20:33 -0400, John Doe <jd...@doe.org> wrote:
>>
>>>Is Ares1X the first rocket where the main engine consists only of an SRB ?
>>
>> Nope. Scout, Pegasus, Taurus, Athena...
>
>Most launchers (and ICBM's) that I'm aware of with a solid only first stage
>have a solid second stage as well. As far as I know, Ares I is the first
>big launcher where the first stage is solid and the upper stage is liquid.
ISTR the Russians experimented with that. Depending on how you count
such things, both Minuteman and Polaris Chevaline use/used liquid
fueled busses.
Dr J R Stockton
Wed, 28 Oct 2009 13:54:40, Jeff Findley <jeff.f...@ugs.nojunk.com>
posted:
>The press conference following is giving some indication that the first
>stage did recontact the upper stage simulator after separation, but they're
>not outright admitting it yet. This is a problem with SRB's. The thrust
>doesn't stop cleanly like a liquid engine. It slowly tails off. And with
>the hammer head design of the vehicle, getting a clean separation will be a
>challenge.
Mount the separation motors on the upper stage, where the thrust will be
multiply beneficial; and drop them when empty, just as is commonly done
when a first stage starts. Give pairs slightly different burn-lengths,
to minimise the "jerk" when they burn out. That also serves for ullage.
If the thrust profile of those add-ons can be made slow-start, they can
be lit when the first stage thrusts begins to drop off, smoothing the
transition.
--
(c) John Stockton, near London. *@merlyn.demon.co.uk/?.?.Stockton@physics.org
Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
Correct <= 4-line sig. separator as above, a line precisely "-- " (SoRFC1036)
Do not Mail News to me. Before a reply, quote with ">" or "> " (SoRFC1036)
Jorge R. Frank
> In sci.space.shuttle message <d4060$4ae88561$927a2cda$21...@FUSE.NET>,
> Wed, 28 Oct 2009 13:54:40, Jeff Findley <jeff.f...@ugs.nojunk.com>
> posted:
>
>> The press conference following is giving some indication that the first
>> stage did recontact the upper stage simulator after separation, but they're
>> not outright admitting it yet. This is a problem with SRB's. The thrust
>> doesn't stop cleanly like a liquid engine. It slowly tails off. And with
>> the hammer head design of the vehicle, getting a clean separation will be a
>> challenge.
>
> Mount the separation motors on the upper stage, where the thrust will be
> multiply beneficial; and drop them when empty, just as is commonly done
> when a first stage starts. Give pairs slightly different burn-lengths,
> to minimise the "jerk" when they burn out. That also serves for ullage.
>
The real Ares I is already planned to have such motors; Ares I-X did not.
<http://www.nasa.gov/mission_pages/constellation/ares/ullage_motor.html>
Cyberia
> "Cyberia" <n3...@comcast.net> wrote:
>
>>There is probably plenty of clearance despite this motion, given that the
>>various service arms are rotated out to the sides. It still looks to me,
>>however, that gimballing the RSRM motor so that the aft end of the rocket
>>moves *away* from the tower rather than toward would give much more
>>clearance. The rocket could end up flying over the tower but all parts of
>>its airframe would have more clearance from that structure on the way up.
>
> Not only does that maneuver place the entire length of the booster at
> risk, it also means thrusting *away* from your desired flights path
> (which means taking a payload/performance hit).
Yes, there would be impact to performance.
> This alone means you planned manuver is a very bad idea based on
> assumptions shown to be incorrect.
I re-read your first response to me, and I missed the subtle differentiation
you made when you said the maneuver was intended to move the flight path,
not to increase the clearance. This is the assumption I made (increasing
clearance) to which you refer, correct?
> And if that wasn't bad enough - a flight path towards and over the
> tower *places the booster on a trajectory leading inland towards
> populated areas*.
>
> Which isn't happening.
Now that seems to be solid reasoning not to gimbal the other way. :-)
David Spain
> The real upper stage will also have ullage motors firing before the J-2X
> to settle the propellants and, not coincidentally, to increase the
> separation rate.
>
Yes I was thinking that as well in another thread.
In another thread it was mentioned the possibility of 'sporadic afterburning'
as the booster burns out. Assuming this is a real phenomena of solids, would
it make more sense to initiate separation and ullage burn slightly before
SRB burnout when solid rocket performance is still stable? Or can the ullage
rockets only increase the separation rate after thrust drops on the first stage?
This business seems to be a lot more complex than it would appear to be
on first glance!
Dave
Derek Lyons
>I re-read your first response to me, and I missed the subtle differentiation
>you made when you said the maneuver was intended to move the flight path,
>not to increase the clearance. This is the assumption I made (increasing
>clearance) to which you refer, correct?
Correct. The idea is to fly away from the tower in order to reduce
the chance of wind induced collision, not to increase clearance
between the vehicle and the tower.
John Doe
> Correct. The idea is to fly away from the tower in order to reduce
> the chance of wind induced collision, not to increase clearance
> between the vehicle and the tower.
Why would the Shuttle not need such a manoeuver right at lightoff, but
Ares would need such a pronounced manoeuver ?
Since you can't move directly away from the tower (since thrust would
then be directed at the tower), is there really much of a point in
trying to deal with the wind for what, 2-3 seconds ?
Or is this necessary because the top end of the rocket, being wider,
offers greater wind pressure and thus acts as a lever pushing the top
end more than the lower end, and they must counter this immediatly ?
Derek Lyons
>Derek Lyons wrote:
>
>> Correct. The idea is to fly away from the tower in order to reduce
>> the chance of wind induced collision, not to increase clearance
>> between the vehicle and the tower.
>
>
>Why would the Shuttle not need such a manoeuver right at lightoff, but
>Ares would need such a pronounced manoeuver ?
The Shuttle is a) heavier, and b) has a lower finess ratio. It's not
as vulnerable.
Jorge R. Frank
> John Doe <jd...@doe.org> wrote:
>
>> Derek Lyons wrote:
>>
>>> Correct. The idea is to fly away from the tower in order to reduce
>>> the chance of wind induced collision, not to increase clearance
>>> between the vehicle and the tower.
>>
>> Why would the Shuttle not need such a manoeuver right at lightoff, but
>> Ares would need such a pronounced manoeuver ?
>
> The Shuttle is a) heavier, and b) has a lower finess ratio. It's not
> as vulnerable.
The shuttle also has lower limits on wind velocity at liftoff due to the
need to protect for abort landings. The low wind limits also contribute
to make a tower avoidance maneuver unnecessary for the shuttle. Ares I
is intended to have much looser wind limits, including winds toward the
pad, so it needs one, just like the Saturn V did.
If Ares I were restricted to the same wind limits as the shuttle, it
probably wouldn't need nearly as much of a tower avoidance maneuver (it
will still need at least a small one, since (as you say) it is much taller).
Me
> Yes I was thinking that as well in another thread.
> In another thread it was mentioned the possibility of 'sporadic afterburning'
> as the booster burns out. Assuming this is a real phenomena of solids, would
> it make more sense to initiate separation and ullage burn slightly before
> SRB burnout when solid rocket performance is still stable?
> Dave
No, because ullage rockets aren't hat high of thrust and the SRB would
run into the separating stage
John Doe
they use thrusters in the upper levels of the rocket to compensate for
the wind instead of "leaning" the whole rocket into the wind ?
Derek Lyons
Me
No, it is inefficient, more complicated and not needed. Also the
thrusters would make the vehicle react the same way. The vehicle is
going to rotate around its c.g. whether it is pushed from the top or
bottom