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#540
by
Jim
on 04 Dec, 2010 18:32
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Wow - 2300fps delta-V through two 110 lbf thrusters.
So, if this thing is the SR-71 replacement, this is probably to make it hard to predict where and when it will fly over you. Lots of delta-V for lots of orbital maneuvers and for makeup thrust for atmospheric drag in low-altitude conditions.
Again, who said this was a reconsat much less an SR-71 replacement.
Remember this was a NASA project before and it drove the design, not earth observation requirements.
There are better existing systems to get this data
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#541
by
Lee Jay
on 04 Dec, 2010 18:36
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Wow - 2300fps delta-V through two 110 lbf thrusters.
So, if this thing is the SR-71 replacement, this is probably to make it hard to predict where and when it will fly over you. Lots of delta-V for lots of orbital maneuvers and for makeup thrust for atmospheric drag in low-altitude conditions.
Again, who said this was a reconsat much less an SR-71 replacement.
Remember this was a NASA project before and it drove the design, not earth observation requirements.
There are better existing systems to get this data
It's classified, so this was nothing but a guess.
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#542
by
Jim
on 04 Dec, 2010 18:36
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From NTRS:
I posted long ago that it was 100lbf thrusters and biprop
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#543
by
mmeijeri
on 04 Dec, 2010 18:41
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I posted long ago that it was 100lbf thrusters and biprop
I know, and that's when I first heard about it. There was some talk about X-37 using kerosene/peroxide and you said that was an old plan and that hypergols would be used instead. I don't recall if someone posted the link then or if I stumbled upon it later.
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#544
by
iamlucky13
on 04 Dec, 2010 20:03
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#545
by
Jim
on 04 Dec, 2010 20:11
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#546
by
JosephB
on 04 Dec, 2010 20:25
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#547
by
JimO
on 04 Dec, 2010 21:16
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#548
by
Lee Jay
on 04 Dec, 2010 21:28
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re the page 5 Figure 4 System Configuration.
can anybody create and post a unified jpg? All i can
copy are thin strips.
Attached.
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#549
by
JosephB
on 04 Dec, 2010 21:54
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Video: X-37B Landing at Vandenberg AFB.
Correct me if I'm wrong but this clip is the only (that I know of) image that shows the aft end. It looks like there is only one engine, right?
42-47 sec in clip
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#550
by
edkyle99
on 05 Dec, 2010 02:26
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From NTRS:
X-37 Storable Propulsion System Design and Operations
110 lbs thrust MMH/N204. Sounds and looks an awfully lot like IHI's 500 N engine, used by JAXA's HTV.
http://www.ihi.co.jp/ia/en/product/satellite.htmlsays that "As of February 2010, ... 17 units of the 500 N engine have been flown, and .... 31 units of the 500 N engine have been exported."
IHI also supplied the apogee engine used by AEHF 1, the DoD satellite that failed to reach orbit as originally planned this summer. I believe that Orbital's Cygnus also uses IHI engines.
Could it be that the United States can no longer supply propulsion for even its secret spacecraft? Perhaps this is why there's been no mention of the specifics, only allusions to potential systems, etc.
- Ed Kyle
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#551
by
JosephB
on 05 Dec, 2010 11:21
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Good point. Although it's probably not an issue of can't, but rather why not.
Pre-existing, right sized & priced right.
Does the US have a known engine similar to this one?
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#552
by
JimO
on 05 Dec, 2010 11:52
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Attached.
Thanks, Lee Jay. I'm an old 'PROP officer" from early STS days (on console for STS-1 ascent), so plumbing specs/schematics are a trip down memory lane.
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#553
by
Skyrocket
on 05 Dec, 2010 13:12
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Good point. Although it's probably not an issue of can't, but rather why not.
Pre-existing, right sized & priced right.
Does the US have a known engine similar to this one?
The
X-37 Storable Propulsion System Design and Operations document mentiones the venerable Aerojet R4D as the propoesed OME for X-37B
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#554
by
kevin-rf
on 05 Dec, 2010 13:13
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Correct me if I'm wrong but this clip is the only (that I know of) image that shows the aft end. It looks like there is only one engine, right?
42-47 sec in clip
The aft end view at 1:10 clearly shows a single engine. Honestly, a single engine does simplify the design, improve reliability, reduce mass, and removes thrust imbalance issues that two could cause. Two says to me, "we no longer make the right sized engine".
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#555
by
JosephB
on 05 Dec, 2010 13:29
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Good point. Although it's probably not an issue of can't, but rather why not.
Pre-existing, right sized & priced right.
Does the US have a known engine similar to this one?
The X-37 Storable Propulsion System Design and Operations document mentiones the venerable Aerojet R4D as the propoesed OME for X-37B
There were words in that document?
I'll confess to getting hung up on the image. Guilty.
Thanks for pointing Aerojet out!
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#556
by
kkattula
on 05 Dec, 2010 13:49
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Correct me if I'm wrong but this clip is the only (that I know of) image that shows the aft end. It looks like there is only one engine, right?
42-47 sec in clip
The aft end view at 1:10 clearly shows a single engine. Honestly, a single engine does simplify the design, improve reliability, reduce mass, and removes thrust imbalance issues that two could cause. Two says to me, "we no longer make the right sized engine".
Most of the shots are from level at 90 degs, so hard to be sure. But this view looks like only one nozzle:
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#557
by
kevin-rf
on 05 Dec, 2010 14:07
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#558
by
robertross
on 05 Dec, 2010 14:13
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this view shows one,
Classic perspective problem.
If you look at the above photo (previous), the placement of the through-hole for the engine mount is to the right of that center hole seen at the top of the rear bulkhead.
The chances they have only one engine off-axis is close to nil. We just aren't seeing the left engine: it has to be there.
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#559
by
Pedantic Twit
on 05 Dec, 2010 14:27
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Perhaps we need to go back to pre-launch photos
like this one.
I only see a single engine (but there's quite a bit of stuff in the way).