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#1200
by
Propforce
on 21 May, 2010 15:03
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I just had a throw away question not important enough for its own thread.
I was thinking of an Ares 1-like rocket, but where the second stage is positioned so that it can also contribute to the thrust during lift off, throttling back to keep acceleration constant as total mass drops, and then is restarted or throttled up when the first stage drops away.
However this would put the exhaust of the second stage, being on top, rather close to the solid first stage. I was wondering if that was acceptable for solid rockets or rules this idea out. Also I was wondering what seriously considered plans most resembled this.
Just build a better 1st stage.
In the case of Ares 1, the problem is not the lack of thrust from the 1st stage, it is the lack of "range", e.g., need more propellant therefore a bigger diameter SRB.
In your proposed idea, then we will need to build a "bigger" 2nd stage tank because you're taking the propellant dedicated for a 2nd stage flight to "subsidize" the 1st stage. But if you build a bigger 2nd stage tank, it gets heavier and we will need "more" thrust from the 1st stage which is exactly the problem we try to fix. See the problem?
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#1201
by
Robotbeat
on 22 May, 2010 22:13
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What was the mass of the rescue balls, including the 1-hour life support?
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#1202
by
Aobrien
on 23 May, 2010 15:09
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Is there a way to get the live displays in MCC on your computer. Such as the live map and live configuration?
Thanks
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#1203
by
elmarko
on 23 May, 2010 15:25
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Not the official one but there are lots of other ones that do similar things like show the map etc.
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#1204
by
kraisee
on 23 May, 2010 16:40
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That's a missed opportunity from NASA PAO.
They really should provide an app which shows the big MCC map, indicating ISS, Shuttle, Soyuz, Progress, ATV, HTV, COTS & CCDev, plus Hubble of course
They should do it as a screensaver and/or an active wallpaper. I think there would be thousands of people who would use it as their default screens. It would be good 'advertising' for NASA.
Ross.
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#1205
by
Aobrien
on 24 May, 2010 02:06
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That's a missed opportunity from NASA PAO.
They really should provide an app which shows the big MCC map, indicating ISS, Shuttle, Soyuz, Progress, ATV, HTV, COTS & CCDev, plus Hubble of course
They should do it as a screensaver and/or an active wallpaper. I think there would be thousands of people who would use it as their default screens. It would be good 'advertising' for NASA.
Ross.
Couldn't agree with you more.
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#1206
by
iskyfly
on 26 May, 2010 16:40
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Regarding entry attitude. What dictates the attitude? Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?
Looking at reply #82 in this thread;
http://forum.nasaspaceflight.com/index.php?topic=21764.75Thanks!
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#1207
by
iskyfly
on 26 May, 2010 16:42
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#1208
by
Jim
on 26 May, 2010 18:03
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Regarding entry attitude. What dictates the attitude? Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?
Looking at reply #82 in this thread;
http://forum.nasaspaceflight.com/index.php?topic=21764.75
That is the attitudes in relation to LVLH (local vertical local horizon), inertial and the sun. They are constantly changing during entry. The angle of attack is what is fixed.
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#1209
by
iskyfly
on 27 May, 2010 13:58
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Regarding entry attitude. What dictates the attitude? Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?
Looking at reply #82 in this thread;
http://forum.nasaspaceflight.com/index.php?topic=21764.75
That is the attitudes in relation to LVLH (local vertical local horizon), inertial and the sun. They are constantly changing during entry. The angle of attack is what is fixed.
Thanks for the reply. Sorry, I should have been more specific. I am referring to the numbers called up to the crew for the maneuver to the deorbit position. Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?
Thanks!
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#1210
by
Jim
on 27 May, 2010 14:12
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Thanks for the reply. Sorry, I should have been more specific. I am referring to the numbers called up to the crew for the maneuver to the deorbit position. Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?
It isn't the same because the orbits are slightly different, the orbit in relation to the landing site is different, the orbiter's weight is different, the amount of OMS propellant is different and the amount of excess OMS propellant that needs to be burned off is different.
The attitude is a function of how efficient the burn has to be (the more excess OMS propellant that needs to be burn the more inefficient the attitude is for the deorbit burn). There is a slight affect on cross range with the burn also.
Yes, tens of degree matter, it feeds back in the burn parameters.
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#1211
by
mkirk
on 27 May, 2010 14:19
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What is the name of the screen on the right side?
What is it showing?
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=21764.0;attach=229194;image
Thanks!
Can't really read it well enough from that screen grab, but it looks like the plot of Vrel versus RGO (relative velocity vs Range to Go) used by the FDO (FIDO or fligh dynamics officer) folks. The boundaries represent thermal limits on the left (i.e. don't burn the wings off) and toward the right are minmum bank angles which help assess max range capability.
You may also see other displays such as Altitude vs RGO or E/W (energy) vs RGO and the ground track.
Mark Kirkman
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#1212
by
Jorge
on 27 May, 2010 18:07
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Regarding entry attitude. What dictates the attitude? Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?
Looking at reply #82 in this thread;
http://forum.nasaspaceflight.com/index.php?topic=21764.75
That is the attitudes in relation to LVLH (local vertical local horizon), inertial and the sun. They are constantly changing during entry. The angle of attack is what is fixed.
Thanks for the reply. Sorry, I should have been more specific. I am referring to the numbers called up to the crew for the maneuver to the deorbit position. Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?
Thanks!
Not quite sure what you're referring to here, then. You referenced this post:
http://forum.nasaspaceflight.com/index.php?topic=21764.msg595853#msg5958531) That is the Bird's Eye View (BEV) display of the Entry Interface (EI) attitude, not the deorbit attitude
2) That display is the actual attitude, not the attitude called up to the crew, and the flight controllers like to see it in tenths.
3) The attitude called up to the crew is in whole-number degrees. This is because the MM303 DEORB MNVR COAST display only shows attitude in whole-number degrees. See the DEORBIT MNVR PAD in the ENTRY C/L, items 24-26:
http://www.nasa.gov/centers/johnson/pdf/381558main_ENT_G_H_6.pdf4) The numbers will be different for every entry because the attitude on MM303 is an inertial M50 attitude. Even if the entry attitude was exactly the same in LVLH on every mission, it would be different in M50 due to the rotation of the Earth.
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#1213
by
iskyfly
on 28 May, 2010 14:00
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Not quite sure what you're referring to here, then.
I think I am confused. Let me read the info you kindly provided me and see if I can figure it out.
Thanks to you, Jim and Mark for previous replies.
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#1214
by
iskyfly
on 28 May, 2010 14:05
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#1215
by
chksix
on 28 May, 2010 16:42
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A discussion on a pilot's forum has arisen about the exact speeds and timeframe for Max Q (Max Dynamic Pressure) on the vehicle during launch.
Is the throttle in the bucket during Max Q or in preparation for it?
STS 132 had M .64 to M 1.13. Is that the speed of the vehicle as it passes through Max Q? And is it the same as going through the transonic region in flight?
I searched this section but couldn't find the exact description...
The thread with the discussion:
http://www.pprune.org/jet-blast/414736-sts-132-shuttle-atlantis-4.html (near bottom of page and cont. on next.)
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#1216
by
Jim
on 28 May, 2010 17:01
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Max-q varies for every vehicle and it has nothing to do transsonic.
q= 1/2 * rho * v2
rho is the density of air. But rho decreases with altitude and v is increasing. So early in flight velocity increases and so does q but as altitude is gained, the decrease in rho overtakes velocity and q starts decreasing.
To determine Max-q, the above equation would have to be expanded to include rho as a function of altitude and v as a function of altitude and then the finding the first derivative wrt to altitude and solve for 0.
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#1217
by
chksix
on 28 May, 2010 21:34
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Thank you Jim. Do you know more about the Mach speeds for the throttle bucket in the ascent checklist?
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#1218
by
Jim
on 28 May, 2010 22:31
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Thank you Jim. Do you know more about the Mach speeds for the throttle bucket in the ascent checklist?
I wish I would have seen the graph and it would have made the explanation easier.
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#1219
by
TJL
on 28 May, 2010 23:00
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I have questions regarding the shuttle fly-around upon leaving MIR.
Was this performed back then as is currently with ISS?
If so, on STS 63 was this maneuver flown by shuttle PLT Collins?
Thanks.
