STS-114 Mission Update Thread (Part 4)

[nacnud]

Pork question <img src="/images/icons/rolleyes.gif" />

 

[tap_sa]

Maybe ordinary gasoline would give one extra mach <img src="/images/icons/smile.gif" /><br /><br />edit: uh DoD assets to look at the shuttle while they have a boom they can stick one foot from the TPS .. smart question REALLY smart! <img src="/images/icons/laugh.gif" /><br />

 

[shuttle_rtf]

Even Todd of Florida Today's being negative.<br /><br />I should have the aforementioned comments pertaining to the images I've gained on the PAL Ramp foam over night I'd told...so I'll have a story on site AM UK time tomorrow all being well. <br /><br />Any media lurking on here who are at these Houston conferences, take the story, don't worry about accreditation, ask the damn question.

 

[radarredux]

Talk about a prescient article, check out the date:<br /><br />"ET-121 Crane incident update"<br />5/22/2005 1:27:00 PM<br />http://www.nasaspaceflight.com/content/?id=2323<br /><blockquote><font class="small">In reply to:</font><hr /><p>A USA source has elaborated on the incident involving the External Tank that will fly with STS-114 - ET-121 - noting a crane cable accidentally slapped into the side of the brand new tank.<br />...<br />"Determined not to be an issue but, we'll see if it elevates. Just a shame to have molested a pristine tank."<br />...<br />"We had just a perfect test as far as I'm concerned," said Parsons - repeating comments he - and fellow manager Wayne Hale - noted on the first test.<br /> <br />That proved to be slightly economical with the information when it was revealed that sensor and value issues would ultimately lead to the Shuttle being rolled-back to the Vehicle Assembly Building.<br />...<p><hr /></p></p></blockquote><br /><br />One short article, and it had both the ECO sensor problem and the foam problem two months before they became a major issue!

 

[shuttle_rtf]

I'm only a journalist (and a new one when it comes to professionally reporting this subject matter) . These stories would never happen without sources. I didn't go after the PAL Ramp Foam repair story till SG mentioned it on here and I'm also sure the first time I heard about issues with ECOs was SG on here too. We need this, it's very important if it's utilised correctly. <br /><br />These are the people that should take the credit for resulting information of interest to fans and followers of the STS - of which I'm one of those fans.<br /><br />Update: Bad news, Eric the bird has apparently vapourised in the SRB plume. I doubt he'd of suffered.

 

[redgryphon]

It sounds like Hale is sticking with 114 (and rightly so) while Parsons works 121 and the ET. It also looks like the story is still yours alone. <br /><br />Looking forward to reading it tomorrow. <img src="/images/icons/smile.gif" />

 

[erauskydiver]

The Trident Missile family uses the aerospike. It is deployed just after the missile breaches the water's surface. It basically looks like a long telescoping stick poking out of the top of the missile. The top of the stick has a flat round part. It does significantly reduce the amount of drag on that the missile would have without it. I think this would be a great idea for reducing foam shedding. Though, a Trident missile's aerodynamic characteristics are much different than a shuttle stack's.

 

[shuttle_rtf]

Yes SG, and I've noted it as a counter point to the quote I gained. Appreciated, as while I can't change quotes, I can ommit parts of a quote or counter point incorrect information by way of paraphrase. So it was an important reply (sorry I didn't note it right away, was keeping an eye on Wayne Hale).<br /><br />I'm hoping the bulk quote content for the article (and the real meat to the story) will be forthcoming overnight.

 

[redgryphon]

SG, NASA TV just mentioned the MPLM will actually be returning heavier, at some 19000 lbs, than when it went into orbit. Is the landing mass of Discovery projected to be particularly high, compared to the history of the program?

 

[gofer]

<blockquote><font class="small">In reply to:</font><hr /><p>"I was referring to the microwave aerospike and some of its relatives, which creates a conical shockwave ahead of the parent vehicle, lowering atmospheric drag (and thus stress, thermal effects, etc.) greatly" <br /><br />I have never heard of such a device. <br /><p><hr /></p></p></blockquote><br /><br />Referring to the Cavitation/Supercavitation phenomenon, maybe? Used in the sub torpedo tech, for example. A brief intro: http://www.diodon349.com/Kursk-Memorial/Warpdrive_underwater.htm (don't be frightened by the 'warpdrive' in the html) Air is compressible though, water is not, would that make a difference in usefulness of this technique? Not quite what rocket engine aerospike nozzles are all about though (their main advantage over bell shaped ones being better consistency in performance across a range of altitudes) (sorr for off-topic)<br />

 

[nacnud]

No it's not a supercavitation idea, IIRC the areospike is trying to move the air out the way before the vehcile gets there. The microwave could work by heating the air infont of the vehicle thereby reduceing the atmosphereic pressure.<br /><br />I've not heard of this idea for a few years, I think it was mentioned in NewScientist Magazine about 5 years ago.

 

[redgryphon]

Please don't go to any trouble! <br /><br />Here's what I have found so far. Landing weight for Discovery per the Press Kit is 226,885 lbs. Columbia's for 107 was 232,788 lbs, but I know Columbia was heavier than the others.

 

[tap_sa]

<font color="yellow">"The microwave could work by heating the air infont of the vehicle thereby reduceing the atmosphereic pressure. "</font><br /><br />IIRC the trick is to concentrate enough energy to small area in front of the craft that air there expands 'explosively' creating a shockwave. Kind of virtual spike without drag. Neat idea but the power requirement must be huge, and if it fails during re-entry the sudden airblast hitting vehicles nose might not be a very good thing.

 

[erauskydiver]

Here is a good picture of an aerospike.<br /><br />http://www.navweaps.com/Weapons/WMUS_Trident_C4_and_D5_pic.jpg

 

[nacnud]

Yeah that sounds more like the NS article I read. <br /><br />The nasty failure mode doesn't sound good, especially if the propellant has been reduced because of the new found lower drag co-efficient.<br />

 

[tap_sa]

Interesting pics. In the microwave version there would be an antenna inside the nose cone, concentrating energy to that area where the flat disk at the end of the pole is.

 

[silylene old]

Question: Were there any large foam patch repairs on the <i>Columbia</i> flight? Near the bipod?<br /><br />I am refering of course to the story you are working on, and the references in http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=220&start=1 <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[erauskydiver]

I think the reason that they went that route on Trident was due to the fact that the missile has to be confined to a limited space (ie SSBN Missile Tube), but also has to hold a particular physics package configuration, so they were pretty much limited o designing the missile with a blunt nose cap. Since this would not have been very aerodynamically efficient, they slapped an aerospike on top. If you look at the heritage of FBMs, you will see that the missiles prior to Trident had pointier noses, and were also smaller.

 

[spacefire]

hey what about the 'space blankets' sold at the KSC visitor complex? wrap them around the ET to keep it insulated, instead of selling them to tourists at ridiculous prices! <img src="/images/icons/smile.gif" /><br /><br />on a more serious note, call the Russians and see if they have/had any experience with insulation of cryogenic tanks. now it's not the time to be nationalistic, since American know-how in space is far from its heyday in the 60s... <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[tap_sa]

<font color="yellow">"call the Russians and see if they have/had any experience with insulation of cryogenic tanks."</font><br /><br />The Russians would say 'Why do you fool around with LH2 in the first place? Kerosene is just as good in getting to LEO' <img src="/images/icons/wink.gif" />

 

[nacnud]

US: But the ISP for LOX/H2 is so much better, especialy for a 2nd stage!<br /><br />Russia: What 2nd stage?<br /><br />US: Er....

 

[SpaceKiwi]

I think I've raised this before, and I readily admit I'm no expert in ET foam, but I do wonder at the general wisdom of applying foam in multiple sprays?<br /><br />I don't know if it is feasible to coat the ET in one continuous application, but stacking layers on top of one another, or butting sections up against one another must surely create potential failure points?<br /><br />What is the ET foam like in laymen's terms? Does it have the consistancy of the stuff that comes in angle-iron shaped pieces around your new TV, or is it more like that 'chewy' stuff they make coffee cups out of? <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[nacnud]

I imagine it is simmilar to the stuff you get around a hot water tank, it's certanly the same colour. Is this right?

 

[spacefire]

<font color="yellow">I think this would be a great idea for reducing foam shedding. </font><br />only problem with that, the Aerospike reduces drag at the <b>front</b> of the body and the piece of foam that fell from Discovery was almost halfway down the tank. In fact, the aerospike produces secondary shocks that 'stick' to the missile, as seen in some photos in this paper:<br />http://techreports.larc.nasa.gov/ltrs/PDF/aiaa-95-0737.pdf<br /><br /><br /> <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[nacnud]

Abstract from the paper above:<br /><br />A series of wind tunnel tests have been performed on an aerospike-protected missile dome ata Mach number of 6 to obtain quantitative surface pressure and temperature-rise data, aswell as qualitative flow visualization data. These data were used to determine aerospike conceptfeasibility and will also provide a database to be used for calibration of computationalfluid dynamics codes. Data were obtained on the hemispherical missile dome with and withoutan aerospike that protrudes ahead of the dome along the axisymmetric center line. Datawere obtained on two models (one pressure, one temperature) in the NASA Langley 20-InchMach 6 Tunnel at a freestream Reynolds number of 8.0x106/ft and angles of attack from 0 to40 degrees. Surface pressure and temperature-rise results indicate that the aerospike is effectivefor very low angles of attack (<5 degrees) at Mach 6. Above 5 degrees, impingement ofthe aerospike bow shock and the flow separation shock from the recirculation region createdby the aerospike causes pressure and temperature increases on the windward side of thedome which exceed values observed in the same region with the aerospike removed. Flowcharacterization obtained via oil-flow and schlieren photographs provides some insight intothe quantitative surface data results, including vortical flow and shock-wave impingement.<br />