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#1400
by
ChrisGebhardt
on 05 Nov, 2008 23:01
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Jim..wasn't there also thruster firing concerns from Progress?
Yes, and RFI concerns from Kurs.
Wasn't there also some study out early this year about allowing Shuttle to be docked to ISS during a Soyuz docking or undocking? I seem to remember that there was some interest in allowing this since the distance between the Soyuz docking areas and a docked Shuttle is now greater with the addition of Node-2. If there was such a study, what is its status as I remember they were looking at this for STS-127 in May 2009.
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#1401
by
Jorge
on 05 Nov, 2008 23:10
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Jim..wasn't there also thruster firing concerns from Progress?
Yes, and RFI concerns from Kurs.
Wasn't there also some study out early this year about allowing Shuttle to be docked to ISS during a Soyuz docking or undocking? I seem to remember that there was some interest in allowing this since the distance between the Soyuz docking areas and a docked Shuttle is now greater with the addition of Node-2. If there was such a study, what is its status as I remember they were looking at this for STS-127 in May 2009.
Don't know the status.
Collision concerns are lower with Soyuz since the crew can take over manually from inside, whereas a Progress manual takeover must be done remotely from ISS.
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#1402
by
usn_skwerl
on 06 Nov, 2008 13:07
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many years ago, I heard something about a test or experiment on board the orbiter that proved einstein's theory of relativity. a time difference between ground based and shuttle based atomic clocks. with this issue, how is MET and other times maintained on board the orbiter and/or ISS? are the clocks aboard controlled and updated by MCC every so often?
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#1403
by
ChrisGebhardt
on 06 Nov, 2008 14:43
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many years ago, I heard something about a test or experiment on board the orbiter that proved einstein's theory of relativity. a time difference between ground based and shuttle based atomic clocks. with this issue, how is MET and other times maintained on board the orbiter and/or ISS? are the clocks aboard controlled and updated by MCC every so often?
Don't know about MET (or the theory of relativity proof [I just never heard anything about that]) but I would imagine that the ISS and Shuttle laptops, when cconnected to their respective communication systems, automatically sinc up with the official time much the same way our personal computers do whenever we get online.
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#1404
by
ddunham
on 06 Nov, 2008 15:43
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many years ago, I heard something about a test or experiment on board the orbiter that proved einstein's theory of relativity. a time difference between ground based and shuttle based atomic clocks. with this issue, how is MET and other times maintained on board the orbiter and/or ISS? are the clocks aboard controlled and updated by MCC every so often?
I'm sure they're periodically corrected either from the ground or possibly even from the GPS. But that would be just to compensate for normal clock drift in the computers and other timekeeping devices.
You can measure the effect you refer to (due to several effects of gravity and velocity), but it requires a very accurate clock to see because the effect is quite small. An atomic clock is accurate enough, but I'm not sure if anything like that is normally aboard the ISS. That level of accuracy isn't necessary for many applications. I imagine the test you heard about involved bringing such a clock up and measuring the change after it returned.
The clocks in GPS satellites have a correction of about 450 parts per trillion compared with their operation on the ground. Now they operate in a different region than LEO, but I imagine corrections wouldn't be orders of magnitude different. At that rate, you'd need a clock that drifted less than about a millisecond a week to pick up the difference. Even expensive crystals that are made to be much more accurate than what you find in most computers are usually accurate only somewhere in the parts per billion range.
--
Darren
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#1405
by
mkirk
on 06 Nov, 2008 18:50
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I was hoping Joge might find this question and chime in but in the interim here is a source (from an old copy of the SCOM, DPS Section) that can explain how GPC timing (and thus mission timing) is established better than I can.
http://www.shuttlepresskit.com/scom/26.pdfRefer to the Master Timing Unit on pdf page 14.
Mark Kirkman
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#1406
by
Jorge
on 06 Nov, 2008 20:32
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I was hoping Joge might find this question and chime in but in the interim here is a source (from an old copy of the SCOM, DPS Section) that can explain how GPC timing (and thus mission timing) is established better than I can.
http://www.shuttlepresskit.com/scom/26.pdf
Refer to the Master Timing Unit on pdf page 14.
Mark Kirkman
As far as I know the MTUs have never been updated in flight. The GPCs keep time to the millisecond and for the length of a typical shuttle mission, the MTUs keep time accurately within a half-millisecond, so any errors are lower than the resolution of the GPCs.
There is no capability to update the MTU using GPS time. There is a capability to apply a delta to the MTU using SPEC 2. I believe this would be used for YERO.
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#1407
by
usn_skwerl
on 06 Nov, 2008 22:06
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Outstanding, thanks guys. It's a bit more in depth than I thought it'd be.
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#1408
by
TJL
on 09 Nov, 2008 01:31
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With the shuttle program winding down, I've been putting together a log of "records" and I just wanted to confirm the heaviest (shuttle) payload.
Does that distinction go to Columbia / STS 93 or was it possibly surpassed by one of the classified DOD flights?
Thank you.
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#1409
by
Jorge
on 09 Nov, 2008 01:46
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With the shuttle program winding down, I've been putting together a log of "records" and I just wanted to confirm the heaviest (shuttle) payload.
Does that distinction go to Columbia / STS 93 or was it possibly surpassed by one of the classified DOD flights?
Thank you.
Possibly.
But I'll put it this way: even if I knew of a still-classified DoD flight with a heavier payload, I wouldn't post it publicly until the flight is declassified.
I doubt anyone who actually knows would do so, either.
You're better off going with STS-93 until those flights are declassified.
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#1410
by
pr1268
on 11 Nov, 2008 03:34
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With the shuttle program winding down, I've been putting together a log of "records" and I just wanted to confirm the heaviest (shuttle) payload.
Does that distinction go to Columbia / STS 93 or was it possibly surpassed by one of the classified DOD flights?
Thank you.
Possibly.
But I'll put it this way: even if I knew of a still-classified DoD flight with a heavier payload, I wouldn't post it publicly until the flight is declassified.
I doubt anyone who actually knows would do so, either.
You're better off going with STS-93 until those flights are declassified.
Which one was the lowest payload among STS missions? (Assuming, of course, that this isn't classified as well.)
My intuitive guess is one of the earliest ones (like STS-3 or 4 since they were only 2 crew but didn't have to haul unneeded paint to orbit).
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#1411
by
Jim
on 11 Nov, 2008 12:12
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STS-1 DFI pallet
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#1412
by
brahmanknight
on 11 Nov, 2008 12:19
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Is there a list of the terms for space shuttle processing ( S0007, S0017, ect )?
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#1413
by
Jim
on 11 Nov, 2008 12:29
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#1414
by
brahmanknight
on 11 Nov, 2008 20:56
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A friend of mine says he heard that STS 126 will be the the last night launch. He says WESH 13 out of Orlando reported that this week.
As far as I understand it, we have no idea if it is the last night launch since it is determined by where the station is one the day we want to launch.
Am I missing something, or did WESH 13 make an error?
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#1415
by
Jorge
on 11 Nov, 2008 21:01
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A friend of mine says he heard that STS 126 will be the the last night launch. He says WESH 13 out of Orlando reported that this week.
As far as I understand it, we have no idea if it is the last night launch since it is determined by where the station is one the day we want to launch.
Am I missing something, or did WESH 13 make an error?
Your understanding is correct. The WESH report is in error.
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#1416
by
rdale
on 11 Nov, 2008 21:06
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I don't see anything on WESH's site referring to this as the last night launch, so your friend just heard wrong it sounds like...
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#1417
by
Austin
on 13 Nov, 2008 02:15
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Not quite sure if this is a comment or a question...but I have always been amazed at the forward struts (the "V" configuration). The aft struts at the base of the orbiter (connecting to ET) seem quite strong and sturdy enough, but the forward strut attach point (beneath the forward gear) just doesn't seem strong enough to withstand the weight of the orbiter and tremendous vibration of launch. I'm always amazed that it holds strong.
Can anyone provide info on how that seemingly skinny attach point supports these forces (weight and vibration)? Not sure if anyone can speak to what the struts are made of...
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#1418
by
Lee Jay
on 13 Nov, 2008 02:20
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Not quite sure if this is a comment or a question...but I have always been amazed at the forward struts (the "V" configuration). The aft struts at the base of the orbiter (connecting to ET) seem quite strong and sturdy enough, but the forward strut attach point (beneath the forward gear) just doesn't seem strong enough to withstand the weight of the orbiter and tremendous vibration of launch. I'm always amazed that it holds strong.
Can anyone provide info on how that seemingly skinny attach point supports these forces (weight and vibration)? Not sure if anyone can speak to what the struts are made of...
You answered your own question. The aft struts support the weight (or thrust), the bipod at the front does not. Instead it just keeps the nose of the orbiter at the proper distance from the tank.
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#1419
by
Austin
on 13 Nov, 2008 02:22
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Not quite sure if this is a comment or a question...but I have always been amazed at the forward struts (the "V" configuration). The aft struts at the base of the orbiter (connecting to ET) seem quite strong and sturdy enough, but the forward strut attach point (beneath the forward gear) just doesn't seem strong enough to withstand the weight of the orbiter and tremendous vibration of launch. I'm always amazed that it holds strong.
Can anyone provide info on how that seemingly skinny attach point supports these forces (weight and vibration)? Not sure if anyone can speak to what the struts are made of...
You answered your own question. The aft struts support the weight (or thrust), the bipod at the front does not. Instead it just keeps the nose of the orbiter at the proper distance from the tank.
Ah, suppose I suspected that.
Gracias!
