SpaceX News

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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Aero
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Re: SpaceX News

Post by Aero »

Does anyone suppose that the techniques developed for the return of the fairing would have any carry-over to the return of the second stage?
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Maui
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Re: SpaceX News

Post by Maui »

I'm guessing not really. I think the big issue issue for the 2nd stage is that it will be going that much faster and thus will require that much better of a heat shield and/or fuel to slow down. Not clear to me how this translates into recovering the fairings which strikes me as likely more of an aerodynamic control issue.

I wonder if it has been considered to use one part of the fairing as a sacrificial heat shield for the 2nd stage?

Tom Ligon
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Re: SpaceX News

Post by Tom Ligon »

I knocked around some numbers a few years back when Arlan Andrews, Stephanie Osborn, and I were working on our scheme for an ejection seat that could make an orbital re-entry. We concluded it was possible. We were looking at a variation of the inflatable heat shields (IRVE) NASA has been experimenting with for Mars entry. Our scheme was, instead of inflating the cone-shaped shield with air, we would use fast-setting polyisocyanurate foam. This would avoid deflation and aeroelasticity issues, and add insulation. My tests showed the foam can take the heat flux of a full-bore re-entry, but we would expect this draggy shield to slow the ejection seat at much higher altitude than a typical capsule.

Low ballistic coefficient objects slow down fast. Think of what happens with a beach ball and an arrow of similar mass.

Whatever the fairing can withstand going up, as long as the ballistic coefficient is low enough that drag makes it slow down as it descends, enough that it does not experience aerodynamic heating beyond its design, it should be fine. One set of dimensions of our ejection seat was so draggy that it would have a sea level terminal velocity of something like 40 mph. At that speed, a water landing could be survived without a parachute (the occupant is reclined in a couch and facing rearward).

I would guess fairings are made of something like honeycomb. They should float.

paperburn1
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Re: SpaceX News

Post by paperburn1 »

I know for a fact that it was/is a recovery and reuse option. Fairing were recovered with damage in march and it has been speculated the remanufacture cost only to be 100,000s of dollars vice 2 million for a new set if you could soft land one. The real problem seem not being the landing but landing them in a recoverable location. Once again the tyranny of the rocket equation rears its head and it seems for a lot of launch option it would be viable but not so much for other shots. Just like the booster recovery program.
The fairing is jettisoned as soon as possible usually during the second stage burn, normally 30 seconds after the second stage fires.. so it would normally be over the ocean and require a second recovery team. I believe the current development effort is to "fly" the clamshell back to a suitable recover area and have a parachute landing. Like the barge or some offshore location that is easily reachable and would not endanger shipping lanes and recreational boating. This also would eliminate the need for the second team and make it more economically viable.
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http://www.spacex.com/sites/spacex/file ... ev_2.0.pdf
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choff
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Re: SpaceX News

Post by choff »

CHoff

Maui
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Re: SpaceX News

Post by Maui »

That sounds like a pretty direct competitor to Vector Space Systems.

Wonder how many players the micro-satellite industry can support? How big can it get without making space junk an unmanageable issue?

Skipjack
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Re: SpaceX News

Post by Skipjack »

Maui wrote:That sounds like a pretty direct competitor to Vector Space Systems.

Wonder how many players the micro-satellite industry can support? How big can it get without making space junk an unmanageable issue?
I thought most new satellites have to be able to go into a garbage orbit at the end of their lives?

hanelyp
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Re: SpaceX News

Post by hanelyp »

Somewhere awhile back I seem to recall there being an international agreement about satellites in geosynchronous orbit shifting to a disposal orbit at end of life.
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paperburn1
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Re: SpaceX News

Post by paperburn1 »

https://orbitaldebris.jsc.nasa.gov/
The NASA Orbital Debris Program Office, administratively located at the Johnson Space Center, is recognized world-wide for its initiative in addressing orbital debris issues. The NASA Orbital Debris Program Office has taken the international lead in conducting measurements of the environment and in developing the technical consensus for adopting mitigation measures to protect users of the orbital environment. Work at the Center continues with developing an improved understanding of the orbital debris environment and measures that can be taken to control debris growth.
I am not a nuclear physicist, but play one on the internet.

krenshala
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Re: SpaceX News

Post by krenshala »

Skipjack wrote:
Maui wrote:That sounds like a pretty direct competitor to Vector Space Systems.

Wonder how many players the micro-satellite industry can support? How big can it get without making space junk an unmanageable issue?
I thought most new satellites have to be able to go into a garbage orbit at the end of their lives?
I think Maui was referring to the sheer volume of active objects in orbit if we end up with a (relatively) large number of micro-satellite providers.

Skipjack
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Re: SpaceX News

Post by Skipjack »

krenshala wrote:
Skipjack wrote:
Maui wrote:That sounds like a pretty direct competitor to Vector Space Systems.

Wonder how many players the micro-satellite industry can support? How big can it get without making space junk an unmanageable issue?
I thought most new satellites have to be able to go into a garbage orbit at the end of their lives?
I think Maui was referring to the sheer volume of active objects in orbit if we end up with a (relatively) large number of micro-satellite providers.
I think most micro- satellites are short lived and LEO only.

krenshala
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Re: SpaceX News

Post by krenshala »

Looks like the next SpaceX launch, CRS-11, is this evening at 1755 eastern time (EDT), 1455 pacific. They will be landing the booster back at Kennedy (on land).

Apprently, this launch will be the first reuse of Dragon capsule. According to the article i was reading this one was first launched in the CRS-4 mission.

paperburn1
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Re: SpaceX News

Post by paperburn1 »

Reset for Saturday 507 pm
I am not a nuclear physicist, but play one on the internet.

krenshala
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Re: SpaceX News

Post by krenshala »

Yeah, and the weather looks to be thunderstorms for at least the next week, so they will probably end up scrubbing Saturday's launch attempt.

Maui
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Re: SpaceX News

Post by Maui »

Interestingly, they just bumped the odds of go from 60% to 70% Saturday. Today's radar looked nothing like a 70% go day (as it was supposed to be). Here's hoping for better on Sat.

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