SpaceX Updates (Thread 8)

By DocM
in Science News & Discussion

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Grand Master

bguy_1986

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Posted

I really need to learn some Debian.  Just because I'm in the IT field and it's almost a necessity anymore.  Not really necessary for the little company I work for, but it definitely isn't going to hurt learning more. 

 

I'll sit back and watch the results of others build rockets, using whatever tools are necessary :)

Grand Master

BetaguyGZT

Posted
Posted

That's where the big money is now, but usually big companies have their own IT people. The best bet is to have the skillsets then get a job with 'em. Usually it's not a bad way to go. :yes: Better pick up some programming, the field calls for in-house coding most of the time now.

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Grand Master

bguy_1986

Posted
Posted
13 hours ago, Unobscured Vision said:

That's where the big money is now, but usually big companies have their own IT people. The best bet is to have the skillsets then get a job with 'em. Usually it's not a bad way to go. :yes: Better pick up some programming, the field calls for in-house coding most of the time now.

That's another thing I'd like to learn:  Coding.  My little Company out in the boonies is having trouble finding programmers.  We're a IBM Domino shop so that might have something to do with it, but being out in the boonies definitely doesn't help either.  I'm a Windows Admin so I'm content where I'm at, but would like to stay ahead of things.  Who knows what's going to happen in the next 40 years...

 

 

Anyways, probably should get back on subject :D.

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Grand Master

DocM

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Commented

 

Jeff Foust @jeff_foust
Josh Brost, SpaceX: should have LC-39A activated for launches in less than a month, hopefully F9 launch from there later this year.
>
>see below
>
Peter B. de Selding @pbdes
SpaceX manifest: Round & round it goes, where it stops... EchoStar-23 is latest customer said to be maneuvering for F9 return-to-flight slot
>
Stephen Clark @StephenClark1
Michael Freilich/NASAs Earth science division: Pegasus/CYGNSS launch from Cape now Dec. 12. Next SpaceX station cargo flight around Jan. 15
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>[CRS-10]
>
James Dean ✔ @flatoday_jdean
Space Florida's board has approved giving SpaceX $5M to help install Falcon/Dragon crew access arm at KSC's historic pad 39A.
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>[handshake deal pending future projects. Boeing got SS $ too]
>
Jeff Foust @jeff_foust
French: see opportunities in the future for partnerships like Red Dragon agreement with SpaceX, but for cislunar space activities.

>

>[THIS is the Big Deal - a series of lunar COTS programs are coming, RFI & RFP formulations underway, with the odds of a new president - either - refocussing part of NASA's  manned efforts to the Moon]

Edited by DocM
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Grand Master

BetaguyGZT

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Posted (edited)

Wooooooohoooooo! Cislunar Missions! Does this mean we could see testing of the Earth-Moon Lagrange (EML) Points for possible ... whatevers? :D :rofl: They might have to build a Grey Dragon variant for these purposes ...

 

I like. A lot. :yes:(Y) 

 

[EDIT] I'm looking at the Delta-V maths for EML points .... and I like what I see. Literally the "Gateways to Everywhere". A mere +0.86m/sec is all ya need to leave E-M SOI at EML-1, and an even more easy-peasy +0.4m/sec at EML-2. Child's play. :D 

 

Reference: http://space.stackexchange.com/questions/3770/minimum-delta-v-to-a-staging-area-in-cislunar-space-for-a-vertical-space-gun

Edited by Unobscured Vision
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Grand Master

DocM

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9 minutes ago, Unobscured Vision said:

Wooooooohoooooo! Cislunar Missions! Does this mean we could see testing of the Earth-Moon Lagrange Points for possible ... whatevers? :D :rofl: They might have to build a Grey Dragon variant for these purposes ...

 

I like. A lot. :yes:(Y) 

Yes.

Grand Master

DocM

Posted
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Posted (edited)

Lunar and Earth Lagrange (L) points are gravitational nodes between bodies; Sun-Earth, Earth-Moon etc., and L1 & L2 are of particular interest because they lie on what's known as the Interplanetary Transport Network (ITN) - gravity assisted paths which allow low delta-V (energy) transit between solar system bodies.

 

http://www2.esm.vt.edu/~sdross/papers/AmericanScientist2006.pdf

 

Go to an L1 station, between the Earth and Moon, assemble the mission and it takes very little energy (fuel) to go most anywhere. Time is another issue, so more delta-V applied can get you there faster using an alternate geometry

 

 

AAGJvD1-1360x1655.png

 

 

Interplanetary_Superhighway.jpg

 

Edited by DocM
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Grand Master

DocM

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Quote

October 28, 4:00pm EDT

 

The Accident Investigation Team continues to make progress in examining the anomaly on September 1 that led to the loss of a Falcon 9 and its payload at Launch Complex 40 (LC-40), Cape Canaveral Air Force Station, Florida.

 

Since the incident, investigators from SpaceX, the FAA, NASA, the US Air Force and industry experts have been working methodically through an extensive fault tree to investigate all plausible causes. As part of this, we have conducted tests at our facility in McGregor, Texas, attempting to replicate as closely as possible the conditions that may have led to the mishap.

 

The investigation team has made significant progress on the fault tree. Previously, we announced the investigation was focusing on a breach in the cryogenic helium system of the second stage liquid oxygen tank. The root cause of the breach has not yet been confirmed, but attention has continued to narrow to one of the three composite overwrapped pressure vessels (COPVs) inside the LOX tank. Through extensive testing in Texas, SpaceX has shown that it can re-create a COPV failure entirely through helium loading conditions. These conditions are mainly affected by the temperature and pressure of the helium being loaded.

 

SpaceX’s efforts are now focused on two areas – finding the exact root cause, and developing improved helium loading conditions that allow SpaceX to reliably load Falcon 9. With the advanced state of the investigation, we also plan to resume stage testing in Texas in the coming days, while continuing to focus on completion of the investigation. This is an important milestone on the path to returning to flight.

 

Pending the results of the investigation, we continue to work towards returning to flight before the end of the year. Our launch sites at Kennedy Space Center, Florida, and Vandenberg Air Force Base, California, remain on track to be operational in this timeframe.

 

 

Grand Master

DocM

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Any or all. Temperature gradients, flow rates etc. can conspire several ways including the thermoacoustic heat engine effect, especially if you're using deep cryogenic LOX (66°K) as SpaceX is doing to get max prop loads. This is really an undiscovered country where no one else has gone before. By using it in a launcher this size, F9 is now in the Proton class, they're writing a new chapter in the textbooks.

Edited by DocM
Grand Master

BetaguyGZT

Posted
Posted

Yeah, really strange stuff can happen at those temps. Like @DocM and @Draggendrop have evidenced previously, the COPV canisters are displaying some really, really temperamental behavior with Liquid Helium sometimes. The sooner they're able to come up with an alternative method of keeping the tanks happy (and keeping the fuels down at the bottom of the tank without needing to use baffles) the better.

 

Examples:

 

sfsfddooof0123456-18.png

 

These are the baffles I'm talking about. They keep fuels from sloshing around during launch, but they reduce your fuel capacity by a lot. Something on the order of 1/6 to 1/4 depending on how many baffles you need and how large they are. They aren't usually porous, and they can get heavy depending on what they're made out of. That's a Saturn fuel tank, and each tank used baffles.

 

crs4_seco_by_inazar-d7zyq2d.gif

 

Here's a Falcon-9. We see the COPV canisters on the sides in place of the baffles. They allow SpaceX to make full use of the tank capacity. It's a far more desirable way to do things, but introduces its' own set of problems (as we're seeing).

 

So, what happens next? I dunno. This one has me stumped for now. I don't think SpaceX wants to use baffles on ITS, but they likely don't want to keep the tanks under these kinds of pressures for upwards of two years or more either ... quite a problem to solve.

Grand Master

DocM

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ITS uses spherical manifold tanks within the spaceships main CH4 and cLOX tanks to keep the in-use volume low and also store thruster, entry and  landing props during the trip.

 

Being smaller and nearly full they are easier to autogenously pressurize by evaporating a small amount of propellant, and to chill using cryo-coolers for zero boil-off during the trip. They're inside the now empty main tanks so are essentially in a thermos bottle, a big dewar, and they also get impact protection from the surrounding structures. 

 

In space a tiny thruster ullage burn can settle the props at the pickups before engine start.

 

Pretty elegant IMO. 

 

SpaceshipManifoldTanks.jpg

Edited by DocM
Grand Master

BetaguyGZT

Posted
Posted

Hey, now we're talking. :yes: Nice solution. Didn't occur to me that it could be done that way. And here I was thinking that the only way around it was to just let 'em slosh during the trip and use verniers to settle the tanks down before use. Heh.

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