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#1460
by
sivodave
on 23 Nov, 2010 06:28
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Hi all.
I was reading this paper
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750021700_1975021700.pdf about the early conceptual studies for the manipulator system (aka robotic arm) of the shuttle. At page 40 there is an interesting paragraph explaining two configurations studied for the end effector.
My question is: why these early concept were discarded? I mean for which reason it has been chosen the configuration that we know for the robotic arm end effector?
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#1461
by
JayP
on 25 Nov, 2010 17:31
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Hi all.
I was reading this paper http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750021700_1975021700.pdf about the early conceptual studies for the manipulator system (aka robotic arm) of the shuttle. At page 40 there is an interesting paragraph explaining two configurations studied for the end effector.
My question is: why these early concept were discarded? I mean for which reason it has been chosen the configuration that we know for the robotic arm end effector?
Its hard to tell without a detailed analysis, but looking at this design, the central pin has to make contact with the bottom of the grapple fixture with enough force to center the effector before the latches can grab the lip at the edge of the fixture. This could imart a motion on the grappled payload that would push it away before they can actually grab it. The SRMS end effector design allows the grapple to be snarred before any axial loads are placed on the payload. It's probably more likely to succeed that the first design.
Basically, this design is a simplified version of the Apollo docking probe. That is probably where they started from when they wrote this report.
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#1462
by
Mark Dave
on 26 Nov, 2010 15:51
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#1463
by
DaveS
on 27 Nov, 2010 15:02
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Assuming no wheel braking at all, what is the rollout distance of the orbiter on a concrete runway without the drag-chute? This for a lightweight orbiter (220k lbs).
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#1464
by
jeff122670
on 27 Nov, 2010 17:42
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during the last press conference for STS-133, Gerst mentioned that shuttle performance is reduced starting in the Feb timeframe. Is that due to warm temperatures reducing propellant performance??
thanks!
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#1465
by
Jim
on 27 Nov, 2010 18:03
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during the last press conference for STS-133, Gerst mentioned that shuttle performance is reduced starting in the Feb timeframe. Is that due to warm temperatures reducing propellant performance??
No,
1. Temp has the opposite affect, warmer SRM's have higher performance.
2. I believe it is the transition period. There is a summer and winter flight profile and they have to use a compromise profile during the transition.
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#1466
by
butters
on 27 Nov, 2010 20:06
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2. I believe it is the transition period. There is a summer and winter flight profile and they have to use a compromise profile during the transition.
Can you (or someone else) please elaborate on that? What is different about the summer and winter flight profiles and why are they necessary? Is it because of atmospheric properties or abort/recovery considerations or perhaps gravitational effects related to the slightly different distance from the Sun?
Is this common to ELVs? Is it common to all non-equatorial launch sites?
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#1467
by
jeff122670
on 27 Nov, 2010 21:45
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Yeah, and I understand warmer SRB's = good performance, but I thought there was something with the SSME's and their propellant that suggested colder was better...
thanks for the answer!!!
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#1468
by
ugordan
on 27 Nov, 2010 22:37
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#1469
by
Jim
on 27 Nov, 2010 23:21
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Can you (or someone else) please elaborate on that? What is different about the summer and winter flight profiles and why are they necessary?
Prevailing upper level winds change seasonally
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#1470
by
TJL
on 28 Nov, 2010 16:25
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I have a question regarding this NASA photo taken of the STS 5 launch.
I'm guessing that it is somewhere east of the Delta 2 launch pads (17), or is it actually south of that near Port Canaveral?
Thank you.
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#1471
by
JayP
on 28 Nov, 2010 17:55
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I have a question regarding this NASA photo taken of the STS 5 launch.
I'm guessing that it is somewhere east of the Delta 2 launch pads (17), or is it actually south of that near Port Canaveral?
Thank you.
I'd say it was someware off of the point of the cape. If it had been from the mouth of the port canaveral channel, the line of blockhouses would have been to the right of the image instead of the left.
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#1472
by
elmarko
on 29 Nov, 2010 09:48
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I'd say that was bang on based on my experience of flying approaches in Orbiter and SSM 07.
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#1473
by
tva
on 29 Nov, 2010 10:28
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I assume that lift-off occurs within tight tolerances in respect of cross-range to the orbital plane of ISS.
How big is this offset measured i kilometers in case of a "default" ascent profile ?
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#1474
by
padrat
on 29 Nov, 2010 20:32
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For the ET, how long does it take for the foam to cure and turn to the familiar orange color the ET has?
actually a fresh ET, ie one that hasn't ever been to the pad, is more of a yellow color. Exposure to the sun causes it to turn dark orange over time.
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#1475
by
Jorge
on 29 Nov, 2010 21:07
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I assume that lift-off occurs within tight tolerances in respect of cross-range to the orbital plane of ISS.
How big is this offset measured i kilometers in case of a "default" ascent profile ?
There's no default; it depends on the phase angle.
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#1476
by
mdo
on 01 Dec, 2010 11:55
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With respect to the still missing root cause for the cracked stringers on ET-137:
Could the problem during mating operations with the orbiter (
reference, IPR-39, Sep. 10) have anything to do with it?
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#1477
by
arkaska
on 02 Dec, 2010 14:20
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How come the ET only can handle 13 cycles? What drives that it can't have more? And have a tank ever gotten close to the max 13 cycles?
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#1478
by
dcbecker
on 02 Dec, 2010 14:31
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How come the ET only can handle 13 cycles? What drives that it can't have more? And have a tank ever gotten close to the max 13 cycles?
material fatigue
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#1479
by
padrat
on 03 Dec, 2010 19:48
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That metal can only be cycled to -423 F and back to ambient only so many times. Heck, at that temp you are basically changing the physical properties of the material. Funny unexpected things tend to happen when it's that cold. Just look at the GUCP. We can leak check it a hundred times at normal temps and it will act like a totally different animal when it goes cryo.