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Other US Launchers / Re: US Launch Schedule
« Last post by crandles57 on Today at 11:14 AM »

None of those were sources for the date in the SpaceX Manifest thread, we've had it at February for months now based on older scheduling information.  Is that when it will actually launch?  We don't know yet.  CRS dates tend to move around, and they rarely move to the left.  CRS-13 just slipped from November to December, so I certainly wouldn't expect CRS-14 to move any earlier than February.

OK, so I was confused about what note 55 meant, but no worries about that. The rest of your answer still confuses me. You don't update to the latest reliable source? If you normally do, why not update Feb 18 to Early 2018 as being the latest information dating to Aug 15, 2017? Perhaps you don't consider SpaceFlightNow launch schedule a reliable source? Sorry if I am asking silly questions.
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Slightly to my surprise the Saturn V works out cheaper in Japan than the U.K. and some outlets still have a bit of stock. So I finally picked up one today at a huge outlet complex in Nagano prefecture central Japan.

Hopefully won't need to buy another suitcase to carry it home :D
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Humanity will never do anything truly substantial in space until it uses NTR of some type.
I have always been an avid supporter of NTR technology so this is really good news.

I support nuclear propulsion research, but do you really think nuclear thermal will be a gamechanger? Merely doubling the specific impulse (while also making the engine heavier and more complex) does not sound like a big advance to me at all. It may not even be worth the added complexity. I do think future will belong to fusion drives or advanced nuclear drives like this:

https://en.wikipedia.org/wiki/Fission-fragment_rocket

https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket

But in the medium term, for inner solar system, I dont really see chemical propulsion as insufficient or a limiting factor. Especially with propellant depots.
It's what NASA is prepared to fund.  :(

Yes it's a doubling of Isp, which looks good next to conventional rocket in Earth to Orbit, but then again air breathing systems can get trajectory averaged of 1300secs+. In space you've ion thrusters with 3000secs+.

NTR scores if you want
a)Short transit time (due to high thrust)
b)Do it on 1 launch.
c)Want a lot of payload in that launch.

The DIA did a study in the 70's of Mars in 70 days, with a Shuttle ET and set of SSME's. The problem is you need to lose about 21Km/sec of delta V at the end.  :(

But once you can split that process up (call it depots. Call it "distributed lift"), or don't want all of those features together,  things get rather more hazy.  :(

However BWXT is what NASA wants.
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Hardest thing to do will probably be dealing with some resonances along the cable to keep the structure stable, but that seems entirely doable to me.

Actually, twisting will be an issue. (In previous AG threads, we discussed a hybrid tensegrity structure using tensioned cables inside an inflatable tube. The combination turns out to be vastly more structurally stable than either alone.)

As will deploying and retracting the cable cleanly. It's been a surprising amount of trouble in experiments so far. Spools are just trouble prone.
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There's nothing inherent in inflatables that is incompatible with their use in spin-stations. (Quite the contrary, I suspect it will make many internal systems easier to develop.)
That I would agree with. Now we just need a rotating space station design that needs them.

Actually inflatables make more sense for AG stations than micro-g ones. People are more volume efficient in micro-g, being able to use every surface, being able to use three-dimensional space, being able to drift over and around things, being able to easily reorientate to reach every surface, it makes smaller spaces seem larger. The moment you move to an artificial gravity station, you're back to standing up and walking around, that means you need more empty floor space (we don't put equipment, cupboards, etc, into the floor), more empty height, and fairly useless ceilings. Even basics like beds and chairs/tables become insanely space occupying (in micro-g you don't "sit", in spite of way, way too many artist's impressions of space station designs that include seats and tables.)

The party trick for inflatables is that they deliver maximum volume for minimum mass. Which is exactly what you want for a spin-station.
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Humanity will never do anything truly substantial in space until it uses NTR of some type.
I have always been an avid supporter of NTR technology so this is really good news.

I support nuclear propulsion research, but do you really think nuclear thermal will be a gamechanger? Merely doubling the specific impulse (while also making the engine heavier and more complex) does not sound like a big advance to me at all. It may not even be worth the added complexity. I do think future will belong to fusion drives or advanced nuclear drives like this:

https://en.wikipedia.org/wiki/Fission-fragment_rocket

https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket

But in the medium term, for inner solar system, I dont really see chemical propulsion as insufficient or a limiting factor. Especially with propellant depots.
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Just read this article:
https://www.nextbigfuture.com/2017/08/air-launched-rocket-for-captive-carry-testing-of-hypersonic-technology.html

It is about the Generation Orbit (https://en.wikipedia.org/wiki/Generation_Orbit_Launch_Services), and it's plans.
Connected to REL, this is written:
Quote
GOLauncher Next represents our vision for highly responsive space access for small payloads up to 1,000 kg or global delivery of payloads up to 3,000 kg. Built around advanced combined-cycle propulsion and reusable high temperature structures, the GONext is being positioned to significantly reduce the cost of space launch and ultra high-speed point-to-point (PTP) flight while preserving the advantages of horizontal launch, basing flexibility, responsiveness, and aircraft-like operations.
(highlite of the propulsion by me)

This sounds like some other initiatives also planning to use the SABRE (or similar engine).
Not really.  :(
"Advanced combined cycle" can (and in the US probably does) just as easily mean Turbine based CC IE Scramjets.
Secondly this is basically a 3rd (or 4th, depending on how you count the stretch version of their 2G ELV) generation concept for them. Their current planned (and follow on) vehicles is more in line with Orbital Accesses plan for a liquid fueled TSTO.

This would really be better in the "general hypersonics" thread in Advanced Concepts, since they list hypersonic research as one of their target markets.

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Japanese Launchers / Re: Japanese launch schedule
« Last post by Salo on Today at 10:12 AM »
http://www.asahi.com/ajw/articles/AJ201705190001.html
Quote
GAMAGORI, Aichi Prefecture—A university team here plans to launch “an artificial star” into orbit that will transmit images of outer space to Earth and be visible to the naked eye.

The ultra-small satellite will be launched aboard an H-2A rocket of the Japan Aerospace Exploration Agency (JAXA) from the Tanegashima Space Center in Kagoshima Prefecture in April next year at the earliest, the team at the Aichi University of Technology said at a news conference on April 28.
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Hmm.

Perhaps a poll of people who think it would be a good idea to go to a composite F9 booster, a full composite F9 or stay as it is?

I think I can guess the outcome but I don't want to say to avoid prejudicing it one way or the other, so I could be wrong.
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The current hypothesis is that the US equivalent are Pan and CLIO, aka Nemesis.
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