STS-114 Mission Update Thread (Part 6)

[georgeniebling]

That they are even *mentioning* White Sands in the Landing Tracks is odd to me .... I can't remember the last time I saw WS mentioned so many times ....<br /><br />I can't imagine NASA *willingly* making the decision to go to WS after the damage to Columbia in '82.<br /><br />----------<br /><br />I noticed both Dyess AFB and Ellsworth AFB are on "the list" .. but Ellsworth is an "underburn for Edwards AFB", isn't Ellsworth *EAST* of Edwards ... so how could a site *east* of the intended target be a backup?<br /><br />I lived in Abilene (Dyess AFB) from 85-88 and 97-03. One of the Shuttles on the SCA landed there ... it was a circus.<br /><br />What is the minimum runway distance for a valid landing site?<br /><br />I seem to remember DFW International being on a list once ... and since I live here now ... right under the approach path for the westside N-S runways (18/36) ... <br /><br />;-)<br />

 

[emerrill]

"I would think by that Q you are asking what happens if they don't land. Basicly they run out of cryo's, so they lose power, which means no anything else (lifesupport, controls, etc). Basicly they WILL land by wednesday. If by some fluke that all the landing sites had below levels weather, they would land through below nominal weather, rather than just let the crew die in orbit(IMO)."<br /><br />And also, just to clarify, that is assuming that the fuel cell reactants are the limiting consumable. I beleive they are, but that would be something that SG or S_RTF (or the like) I think would need to answer.<br /><br />-eric <div class="Discussion_UserSignature"> </div>

 

[emerrill]

"I noticed both Dyess AFB and Ellsworth AFB are on "the list" .. but Ellsworth is an "underburn for Edwards AFB", isn't Ellsworth *EAST* of Edwards ... so how could a site *east* of the intended target be a backup?"<br /><br />Remember, and underburn meens you are going to run long(overshoot), and the trajectory is a west to east.<br /><br />-eric <div class="Discussion_UserSignature"> </div>

 

[georgeniebling]

good point ... underburn means under-reentry burn and so that would create a higher reentry and hence a more easterly landing site ....<br /><br />right?

 

[viper101]

http://www.nasa.gov/returntoflight/launch/landing-vlcc.html <br /><br />"The Virtual Launch Control Center will begin live landing coverage Tuesday, Aug. 9, 2005 at about 3:45 a.m. EDT."

 

[drwayne]

Actually its not "damage" you worry about, its bit flips indiced by induced charge layers.<br /><br />This can lead to program and OS errors and lockups. Commercial laptops operating in such conditions lock up a number of times a day - yes, I know, there's a plethora of Windows jokes to be made there.<br /><br />Wayne<br /><br />p.s. Radiation from the sun, cosmic etc, some of which is trapped in the Earths magnetic field. <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[najab]

Radiation doesn't usually damage the hardware, but the induced current when a charged particle strikes the circuitry can cause random bit-flips. This does happen with cosmic rays striking Earth-bound computers, but much, much less frequently.

 

[drwayne]

You might find this interesting:<br /><br />http://www.klabs.org/DEI/Processor/Papers/<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[najab]

What he said. <img src="/images/icons/smile.gif" />

 

[emerrill]

"So even the computers have to have radiation protection. Is that due to cosmic radiation, or solar, which cuts thru the microcircuitry? I've never seen a good, recent discussion of how radiation in space can damage a computer. It'd be interesting to read something on it. Thanks."<br /><br />The ration causes the molicules in the transistors in ICs to ionize, which causes current leakage. RadHard electronics typicly use a very large manufacture process, so the transistors are made of many more moilcules, so that more ionization is required to make the transistor fail.<br /><br />-eric <div class="Discussion_UserSignature"> </div>

 

[nacnud]

Steve, <br /><br />RAM is not to different in principle from CCDs that are used in cameras. Radiation hitting the RAM can flip bits in the memory and cause all sorts of trouble. <br /><br />Here is a page on a Getaway Special Shuttle experiment that looked at the effect.

 

[najab]

That's one of the main reason that mission critical (either space misson, or business mission) computers usually use ECC RAM - it can detect and usually correct random bit flips.

 

[emerrill]

""So even the computers have to have radiation protection. Is that due to cosmic radiation, or solar, which cuts thru the microcircuitry? I've never seen a good, recent discussion of how radiation in space can damage a computer. It'd be interesting to read something on it. Thanks."<br /><br />The ration causes the molicules in the transistors in ICs to ionize, which causes current leakage. RadHard electronics typicly use a very large manufacture process, so the transistors are made of many more moilcules, so that more ionization is required to make the transistor fail. "<br /><br /><br />A clarification here. There are 2 types of radiation effects. Soft errors (bit flips, stuck bits) that are corrected in software/by a reboot. I was describing a hard errors, which is more a problem for longer missions, because it requires high total dose (soft errors require high instantaneous dose), but the effects of the hard errors are perminant.<br /><br />-eric <div class="Discussion_UserSignature"> </div>

 

[nacnud]

<font color="yellow">I like going to Edwards but I just purchased a ultra Lite aircraft and it is a bad time for me to travel. <br /><br /><font color="white">Too much playing needed <img src="/images/icons/smile.gif" /></font></font>

 

[abacus]

"TAL sites would really be messy since the SCA has not mid air refuling capability. In addition the max ferry altitude is 15,000ft. so the range is greatly reduced. We would have to remove the SSMEs and the payload also."<br /><br />Presumably, you would have the same problem if they had to be used during launch.

 

[emerrill]

"I like going to Edwards but I just purchased a ultra Lite aircraft and it is a bad time for me to travel. "<br /><br />Sweet. I actually just took my Private Pilot check ride yesterday (I passed <img src="/images/icons/smile.gif" /> )<br /><br />-eric <div class="Discussion_UserSignature"> </div>

 

[steve82]

Hey Emerrill, Congrats on the Check Ride!!!!!!!!!<br /><br /><img src="/images/icons/smile.gif" />

 

[lunatio_gordin]

Is that like the driving test for the license? For some reason, I'd much rather try that one than the driving test <img src="/images/icons/tongue.gif" />

 

[spacefire]

wait, the only reason they cancelled the landing was 'low cloud cover'?<br />I'm starting to get swayed to MrMorris's opinion that NASA should go with capsules! <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[emerrill]

"Is that like the driving test for the license? For some reason, I'd much rather try that one than the driving test"<br /><br />Yup, basically. You are proving to an examiner that you are a safe/legal pilot. I was so nervous the few hours leading up to it. Many hours of work, and thousands of dollars come down to a 2 hour test. Luckily the examiner was very nice, and i breezed through it <img src="/images/icons/smile.gif" /><br /><br />-eric <div class="Discussion_UserSignature"> </div>

 

[leclaire]

As my first post to this board (after years of lurking),<br /><br />I'd like to say, Lets close this thread at about 6am EDT!<br />(an extra hour added for some post-landing yee-haa's)

 

[emerrill]

Another operational Q for the 'experts' (or anybody who knows).<br /><br />Is SRB sep based on time, velocity, when thrust drops below x, or what?<br /><br />thanks<br />-eric <div class="Discussion_UserSignature"> </div>

 

[llivinglarge]

Why do the payload bay doors have to be open.

 

[llivinglarge]

How thrashed and sand-logged will Discovery be if it lands at White Sands?

 

[dougbaker]

Just reported, that forcast is showers within in 30 miles for the first attempt.<br /><br />Some are on radar. <br />6:21 GMT <br />1:21 CST<br />