STS-117 (13A) Mission- Part II

[MeteorWayne]

A few comments on the MSB. They pretty much confirmed my speculation about the problem above. Noisy power.<br /><br />More than one question asking what noise is, including one confusing sound noise (it's loud in the space station) with electrical noise.<br /><br />He used the words power quality, which is good.<br />A nice steady unvarying power source is clean. One which varies a lot is "noisy"<br /><br />The compueters wer manufactured by Daimler-Benz, and have been known to be sensitive to noisy power.<br /><br />The start of the problem was concident with the connection of the S3/4 truss, even before power was applied.<br /><br />They switched it off to the FGB, but the switch is a single pole one, only cutting the hot side of the circuit. Meanwhile, the return, or ground side remains connected. Tomorrow they will disconnect the whole cable, removing both circuit paths. <br /><br />I predict success at that point; then it's a matter of finding out how to reconnect the power to the system without letting the noise get through to the computer power.<br /><br />Should be able to be accomplished. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[MeteorWayne]

Good idea, but the scopes are I'm sure not accesible that way.<br /><br />I will volunteer to help explain it to them if needed...that 35 years should pay off.<br /><br />Hopefully they have a few old farts like me around who can explain things to these kids <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[Testing]

The words they had to the crew just before the briefing were to prepare for disconect and break out the tools defer some other stuff. My comment about explaining noise to a non techie was ment to be funny., it can come from anything. Yes, they may be able to configure the scopes from the ground since the age of computers alot of test equipment has comm ports and if they tie it to the comm buss the people aboard just have to probe the desired circuits. Cool Beans. Wayne is vey correct in that analog scopes show everyting whereas digital has gaps in sample rate. Gotta know your limitations. The first time I realized the real power of instrument communication was When an HP Network Anylizer Failed a POST (power on self test) and went brain dead $30,000, one month old. Hp emailed a file, transfer to disc, power up, PRESTO! fixed <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

Yeah the analog to digital change in test instruments and well as television, was a big shift in perspective.<br /> Many did not make the transition, I thrived on it, fluent on both sides of the A/D divide. <img src="/images/icons/cool.gif" /><br /><br />Lotta good it did me <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[Testing]

But Wayne, you can explain things well, and are enthusiastic about what is going on. I hope to finish my career in the industry. Launch and space stress test equipment engineer. Everything we build goes up unless a prototype. More than I can count. I started as an A&P 30 years ago, Oh how things have changed <div class="Discussion_UserSignature"> </div>

 

[thereiwas]

No EE's on this trip. NASA tends towards pilots and mechanical or aerospace engineers. Last EE astronaut I know of was Judy Resnick, tho I havn't checked all the intervening bios. Tho come to think of it Anousheh Ansari had an EE degree....

 

[Testing]

Please do not take this as derogetory but you do not need to be an EE to diagnose this problem. The people aboard have enough engineeing to deal with it supported by ground. One hundred people in Russiia and the US arre working it minimum, each. <div class="Discussion_UserSignature"> </div>

 

[erioladastra]

"What I don't understand is why the restart attempts have to wait for the ISS to be over Russia. Don't we let them use TDRS? Or patch it thru to them? "<br /><br />They get a lot more data over ground sites than through S-band. Plus if it doesn't work, it sends garbage to the US systems and we lose telemetry.

 

[Testing]

Get some sleep when you can. The longesst I ever spent on a console was 10 hours without a minute or two relief, but damn we were happy! Ang it still has not flown. <div class="Discussion_UserSignature"> </div>

 

[scottb50]

Plus if it doesn't work, it sends garbage to the US systems and we lose telemetry...<br /><br />Is that an optional feature?<br /><br />TDRS does seem to be underutilized.<br /><br />I find it odd a U.S. computer could not take over control of a Russian piece of hardware, or that a Russian computer can't takeover control of U.S. hardware.<br /><br />It seemed like there were some post docking attitude anomalies. That would be pretty rough on the computers. Maybe the Shuttle is heavier than thought, or shifting the mass of the truss combined with the mass of Atlantis was too much of a strain.<br /><br />Why don't they have manual control of the systems anyway? I thought that was the point of manned flight? If everything fails someone could not open a valve manually? <br /><br />They get a lot more data over ground sites than through S-band.....<br /><br />And we get more, or probably everything off TDRS, or we use S-band or another?<br /><br />Does TDRS have a normal user base, beyond NASA?<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[bobblebob]

"Russian computers aboard the international space station failed to boot up properly early today even though they were cut off from U.S. solar array power."<br /><br />Thats worrying, as the array and the power coming from it was the most likely cause

 

[emerrill]

I think they are still talking about completely disconnecting them though, since the switch only cutoff the POS side, and could still be introducing GND noise. <div class="Discussion_UserSignature"> </div>

 

[jammers]

There's a list of TDRS users here. It's used by a variety of satellites (including Hubble), the ATV, Sea Launch and McMurdo Station in the Antarctic.

 

[erioladastra]

Latest status:<br /><br />- 1 central computer up, 3 terminals are powered but can't come up<br />- Taken measurements with the scopemeter and everything looks as expected<br />- Talking about bringing home one computer of each set for analysis<br />- Still trying to isolate the SM from new US power.

 

[erioladastra]

"I think they are still talking about completely disconnecting them though, since the switch only cutoff the POS side, and could still be introducing GND noise"<br /><br />Correct. Procedure developed. Still in work. Also, if that doesn't work, may remove a connector on S3 for S6. No power but could cause a ground loop (unlikely) so may disconnect.

 

[erioladastra]

"TDRS"<br /><br />Availability is not the issue. They need Russian grounds sites for best data visibility.

 

[erioladastra]

"10 hours"<br /><br />Weekend shifts are 13 hours.

 

[erioladastra]

"Is that an optional feature? "<br /><br />No, just one of the things that happens when you take two independant systems and staple them together.<br /><br />"I find it odd a U.S. computer could not take over control of a Russian piece of hardware, or that a Russian computer can't takeover control of U.S. hardware. "<br /><br />Not sure I see what you think that is odd. Recall these are two completely independant systems joined at the hip. Getting these two systems to talk to each other was a major effort. Even when one box goes down, having the two sides resume communications on the backup box was tricky sicne both sides use different recovery philosphies. If we had started a few earliers and truly designed an integrated system things would be different of course. Plus some changes we proposed to allow us direct control and vice versus was rejected by the Russians. Now they are really wishing we could command to their FGB systems.<br /><br />"It seemed like there were some post docking attitude anomalies. That would be pretty rough on the computers. Maybe the Shuttle is heavier than thought, or shifting the mass of the truss combined with the mass of Atlantis was too much of a strain. "<br /><br />Sorry, not sure what anomalies you refer too. However, we have been seeing some momentum problems for several days. The shuttle has been using more prop than expected and the ISS has been having trouble with its CMGs. Some thoughts are that the mass properties for the new segment is wrong or that the weight of the shuttle was wrong. Not likely but checking. Or there is a mystery torque out there.<br /><br />"Why don't they have manual control of the systems anyway? I thought that was the point of manned flight? If everything fails someone could not open a valve manually?"<br /><br />The Russians can do that for many systems. However, they can't monitor them with the computers. For example, oxygen systems are very dangerous - you don't want to have it on if you can't monito

 

[MeteorWayne]

Holly Ridings, ISS flight director. interview regarding troubleshooting coming up in 5 min on NASA TV <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[bobblebob]

How often can the Russians communicate with the ISS, and how much is this hindering the troubleshooting task?

 

[bobblebob]

" Talking about bringing home one computer of each set for analysis "<br /><br />How risky is this? If they dont really understand what is causing this, and leaving less backup computers on the ISS, this could very well happen while Atlantis isnt there

 

[MeteorWayne]

Each system has 3 computers, so it will still leave one redundent computer. <br /><br />Not getting this fixed is FAR more risky <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[emerrill]

"How risky is this? If they dont really understand what is causing this, and leaving less backup computers on the ISS, this could very well happen while Atlantis isnt there"<br /><br />Exactly, if this problem comes up again, it effects all paths, so it seems better to have one on the ground to figure out what is really going on. Having that extra path isn't doing any good on the station (as this situation shows). It would be an issue for different problems, but that other problem would still have to take down 2 paths first. Also, Im sure they will be a priority item to go back up once it is all fixed. <div class="Discussion_UserSignature"> </div>

 

[bobblebob]

Could Progess then send the computers back up, or would they need to wait for a shuttle to send it up?

 

[MeteorWayne]

Holly's news was not very good, basically no progress ( <img src="/images/icons/smile.gif" /> ) was made.<br /><br />They did scope out the power yesterday and saw no gross anomolies.<br />Images were sent down (one advantage to digital scopes <img src="/images/icons/smile.gif" /> ) and US and Russian power engineers are chewing on them, both independently and together.<br /><br />They did disconnect completely the new power source from the converters that provide power to the FGB, aparrently no effect.<br /><br />Sounds like tomorrow morning's troubleshooting will be very important. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>