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| Brian Gaff... |
 Posted: Thu Oct 29, 2009 3:01 am |
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Guest
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I think the point is as is said in the often run soundbytes before the
launch, 'we learn even more when things do not go right'
Brian
--
Brian Gaff - briang1 at (no spam) blueyonder.co.uk
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Derek Lyons" <fairwater at (no spam) gmail.com> wrote in message
news:4ae8665a.2918685906 at (no spam) news.supernews.com...
[quote]Lots of self congratulation going on - even though no word of whether
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[/quote] |
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| Brian Gaff... |
| Posted: Thu Oct 29, 2009 3:06 am |
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I can recall how close the first Shuttle launch came to some contact due to
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
--
Brian Gaff - briang1 at (no spam) blueyonder.co.uk
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Cyberia" <n3wz at (no spam) comcast.net> wrote in message
news:q6ydnY7vVaI26XXXnZ2dnUVZ_tqdnZ2d at (no spam) giganews.com...
[quote]
"Greg D. Moore (Strider)" <mooregr_delet3th1s at (no spam) greenms.com> wrote in
message news:H6idnfROso3Z8nXXnZ2dnUVZ_tSdnZ2d at (no spam) earthlink.com...
"Derek Lyons" <fairwater at (no spam) gmail.com> wrote in message
news:4ae8665a.2918685906 at (no spam) 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.
[/quote] |
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| Jeff Findley... |
| Posted: Thu Oct 29, 2009 8:30 am |
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"Brian Thorn" <bthorn64 at (no spam) suddenlink.net> wrote in message
news:dp9ie550p0l06jp46qhudutdkeom599hkd at (no spam) 4ax.com...
[quote]On Thu, 29 Oct 2009 00:20:33 -0400, John Doe <jdoe at (no spam) doe.org> wrote:
Is Ares1X the first rocket where the main engine consists only of an SRB ?
Nope. Scout, Pegasus, Taurus, Athena...
[/quote]
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
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon |
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| Jeff Findley... |
| Posted: Thu Oct 29, 2009 8:34 am |
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"Derek Lyons" <fairwater at (no spam) gmail.com> wrote in message
news:4aea1930.2964468671 at (no spam) news.supernews.com...
[quote]Brian Thorn <bthorn64 at (no spam) 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.
[/quote]
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?
Jeff
--
"Take heart amid the deepening gloom
that your dog is finally getting enough cheese" - Deteriorata - National
Lampoon |
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| Jorge R. Frank... |
| Posted: Thu Oct 29, 2009 9:36 am |
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Cyberia wrote:
[quote]
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.
[/quote]
Not in worst-case allowable winds.
Saturn V did the same thing as Ares. |
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| Brian Thorn... |
| Posted: Thu Oct 29, 2009 11:30 am |
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On Thu, 29 Oct 2009 10:30:17 -0400, "Jeff Findley"
<jeff.findley at (no spam) ugs.nojunk.com> wrote:
[quote]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.
[/quote]
Nope. India's PSLV.
Brian |
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| Derek Lyons... |
| Posted: Thu Oct 29, 2009 11:50 am |
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"Cyberia" <n3wz at (no spam) comcast.net> wrote:
[quote]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.
[/quote]
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.
D.
--
Touch-twice life. Eat. Drink. Laugh.
http://derekl1963.livejournal.com/
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL |
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| Dr J R Stockton... |
| Posted: Thu Oct 29, 2009 12:01 pm |
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In sci.space.shuttle message <d4060$4ae88561$927a2cda$21735 at (no spam) FUSE.NET>,
Wed, 28 Oct 2009 13:54:40, Jeff Findley <jeff.findley at (no spam) ugs.nojunk.com>
posted:
[quote]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.
[/quote]
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. * at (no spam) merlyn.demon.co.uk/?.?.Stockton at (no spam) physics.org
Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
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Do not Mail News to me. Before a reply, quote with ">" or "> " (SoRFC1036) |
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| Derek Lyons... |
| Posted: Thu Oct 29, 2009 12:02 pm |
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Brian Thorn <bthorn64 at (no spam) suddenlink.net> wrote:
[quote]On Thu, 29 Oct 2009 00:20:33 -0400, John Doe <jdoe at (no spam) doe.org> wrote:
Is Ares1X the first rocket where the main engine consists only of an SRB ?
Nope. Scout, Pegasus, Taurus, Athena...
[/quote]
Polaris, Posiedon, Trident, Minuteman, Peacekeeper...
Then a whole raft of one-offs and weirdo's like the X-17, Little Joe,
Little Joe II...
D.
--
Touch-twice life. Eat. Drink. Laugh.
http://derekl1963.livejournal.com/
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL |
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| Derek Lyons... |
| Posted: Thu Oct 29, 2009 12:05 pm |
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John Doe <jdoe at (no spam) doe.org> wrote:
[quote]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 ?
[/quote]
No. That leaves it vulnerable to onshore winds.
[quote]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.
[/quote]
As always, you need to either take fewer drugs or the correct dosage
of your prescribed medications.
[quote]Is there a valid reason to actually program that slant as soon as the
bolts keeping the SRB on the launch platform have fired ?
[/quote]
Yes, to avoid having the booster be blown into the FSS or RSS.
[quote]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 ?
[/quote]
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.
D.
--
Touch-twice life. Eat. Drink. Laugh.
http://derekl1963.livejournal.com/
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL |
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| Derek Lyons... |
| Posted: Thu Oct 29, 2009 12:07 pm |
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"Jeff Findley" <jeff.findley at (no spam) ugs.nojunk.com> wrote:
[quote]
"Brian Thorn" <bthorn64 at (no spam) suddenlink.net> wrote in message
news:dp9ie550p0l06jp46qhudutdkeom599hkd at (no spam) 4ax.com...
On Thu, 29 Oct 2009 00:20:33 -0400, John Doe <jdoe at (no spam) 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.
[/quote]
ISTR the Russians experimented with that. Depending on how you count
such things, both Minuteman and Polaris Chevaline use/used liquid
fueled busses.
D.
--
Touch-twice life. Eat. Drink. Laugh.
http://derekl1963.livejournal.com/
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL |
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| Jorge R. Frank... |
| Posted: Thu Oct 29, 2009 6:44 pm |
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Guest
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Dr J R Stockton wrote:
[quote]In sci.space.shuttle message <d4060$4ae88561$927a2cda$21735 at (no spam) FUSE.NET>,
Wed, 28 Oct 2009 13:54:40, Jeff Findley <jeff.findley at (no spam) 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.
[/quote]
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> |
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| Cyberia... |
| Posted: Sat Oct 31, 2009 10:50 am |
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"Derek Lyons" <fairwater at (no spam) gmail.com> wrote in message
news:4aedd507.3012555765 at (no spam) news.supernews.com...
[quote]"Cyberia" <n3wz at (no spam) 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).
[/quote]
Yes, there would be impact to performance.
[quote]This alone means you planned manuver is a very bad idea based on
assumptions shown to be incorrect.
[/quote]
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?
[quote]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.
[/quote]
Now that seems to be solid reasoning not to gimbal the other way.  |
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| David Spain... |
| Posted: Sat Oct 31, 2009 11:16 am |
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Jorge R. Frank wrote:
[quote]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.
[/quote]
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 |
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| Derek Lyons... |
| Posted: Sun Nov 01, 2009 3:28 pm |
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"Cyberia" <n3wz at (no spam) comcast.net> wrote:
[quote]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?
[/quote]
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.
D.
--
Touch-twice life. Eat. Drink. Laugh.
http://derekl1963.livejournal.com/
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL |
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