OrbitalATK Cygnus OA8, ISS resupply

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DocM    12,760

 

 

 

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Unobscured Vision    2,152

Antares 200, yes?

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DocM    12,760

Yes, using a Ukrainian tank and Russian RD-181 engines. 

 

What could possibly go wrong? :rolleyes:

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Unobscured Vision    2,152

I'm sure we'll find out ... after all, if you aren't blowing up rockets you aren't trying, da?? :laugh::rofl::shifty:

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Unobscured Vision    2,152

Think I'd be more worried about the fuel tanks than the engines, tbh. Orbital seriously can't make those themselves?! Meh. So meh.

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DocM    12,760

There was one report that the Antares 100 explosion was in part caused by debris in the tank being ingested by the (40 year old, improperly stored, Cold War surplus) Russian NK-33 engine.

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Unobscured Vision    2,152

Yep, I remember it well. We did a postmortem in one of my classes when the subject of reuse came up about the old F-1 engines from Apollo/Saturn. Got us sidetracked for the day but it was interesting. Silica powder to eat up moisture was left in the tank, soaked up the RP-1 then settled to the bottom, clogged up the lines then got sucked into the turbopump and poof. RUD recipe.

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DocM    12,760

And yet, during Merlin engine  qualification one of the tests Tom Mueller's SpaceX engineers did was to toss stainless steel nuts into the turbopump propellant supply  lines and see what happened. The Merlin kept on running.

 

 

Edited by DocM
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DocM    12,760

 

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Unobscured Vision    2,152

I saw that this morning on Twitter, and the first thing I thought was "oh holy #### the fines are gonna be REAL" ...

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DocM    12,760

I don't know about that.... there's a story going around that someone did not issue a NOTAM. If true, that someone has some serious splainin' to do.

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Unobscured Vision    2,152

WHOA .... oh boy. That's gonna be someone's ###. In a sling. With duct tape.

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DocM    12,760

 

 

 

 

 

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Unobscured Vision    2,152

200.39 km (127.05 mi) Periapse .... I can't imagine how any Rocket Jock would be satisfied with that orbit .. yech. Talk about underperformance. SpaceX isn't happy until they've got that stuff at least 200 miles up.

 

At 127 miles they're gonna be dealing with atmospheric drag still. The atmosphere doesn't just stay at such-and-such an altitude, it's subject to updrafts, density and pressure differences at that altitude. Any and all effects such as those will decay an orbital track even at 200 or higher -- less than 150 and you're playing cards with the Devil.

 

Don't wanna linger there, ATK. No more than four orbits at that periapse, otherwise you'll be skirting that 100 mile "no go" level.

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DocM    12,760

And yet they're saying that it over performed, which means that they were targeting lower exceeded their expectations and are trying to figure out what to do with the margins. That thing really needs a liquid upper stage

 

 

 

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flyingskippy    126

Are they still limiting the throttle on the 181? I would have thought they would have the new tank running by now. 

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DocM    12,760

This was an Antares 230; the original Ukranian made (KB Yuzhnoye/Yuzhmash) Antares 100 series tanks but with reduced throttle RD-181 engines and an OrbitalATK Castor 30A, 30B or 30XL  solid upper stage.  The difference between Castor's is their burn time,

 

30A: 136s

30B: 127s

30XL: 156s

 

There's an optional Star 48BV solid 3rd stage.

 

Once they use up the warehoused Antares 100 tanks they plan to either, 

 

Builda larger tank for the Antares 300 series, allowing the RD-181's to run at full throttle. Second stage is a Castor XL.

 

or, 

 

They kill Antares after the 100-series tanks run out  and use those resources to build the OrbitalATK Next Generation Launcher, which bears a strong resemblance to the cancelled NASA Ares I and the ATK Commercial Crew entry, Liberty.  3 solids and a Blue Origin BE-3 based upper stage. Return of "The Stick" :rolleyes:

 

Fact sheet: https://www.orbitalatk.com/flight-systems/space-launch-vehicles/NGL/docs/NGL_Factsheet.pdf

 

3097d.jpg

Edited by DocM

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