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Space Science Coverage / Re: Astronomy Thread
« Last post by theinternetftw on Today at 02:40 AM »
Awesome.  A little more on the Titan Wind Tunnel (w/ picture):
https://www.hou.usra.edu/meetings/lpsc2016/pdf/2356.pdf

And planetary wind tunnels in general:
https://www.nasa.gov/ames/planetary-aeolian-laboratory

The Planetary Society also has a great article on tholins:
http://www.planetary.org/blogs/guest-blogs/2015/0722-what-in-the-worlds-are-tholins.html
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I'm curious to see how you plan to physically keep all of this structure together while rotational forces are trying to tear it apart?
The force is one g. We deal with it all the time we build bridges that can carry loads houses with floors as you can walk across. No more stress than everyday life right here on earth.

Yes, we do know how to deal with such stresses here on Earth, but you are imagining a free-flying circular structure with a lot of mass. I'm not an engineer, but that seems like one of those situations where the metaphor "A chain is only as strong as it's weakest link" applies.

If the same ratios apply for this structure as they do here on Earth, then most of the mass used for the station will be for structural elements.

Just some thoughts...
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Blue Origin / Re: Bezos chats up NRO
« Last post by meekGee on Today at 02:22 AM »

ULA's only remaining asset then is a good ops team and familiarity with government customers.

An expendable can compete with a reusable only if it's the only second choice the government has.

If BO is feeling confident they might get ULA in order to help with the competition against SpaceX.

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ABCD: Always Be Counting Down

What are the liabilities that would come with ULA  -pensions? Environmental cleanups?
Does he want a unionised workforce?
It may be more worthwhile to poach staff or buy just the divisions that you want rather than the whole company.
Acquhires of old companies (and ULA includes the old LM and Boeing/McDonnell Douglas heritage both good and bad) don't seem to be as common than for newer companies, probably because of the legacy costs.
Yeah that's a good point

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ABCD: Always Be Counting Down

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Advanced Concepts / Re: Realistic, near-term, rotating Space StationT
« Last post by Roy_H on Today at 01:55 AM »
I like your video it's really well done and brings out several good points. I thought the coriolis effect with pouring water was cute. I imagine it was done in a rapidly spinning environment, and expect it would be neglegable at 2rpm. Athough the big wheels in my drawing would be an assembly problem it's mostly built with modules that could all be sent up with rockets.
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Blue Origin / Re: Bezos chats up NRO
« Last post by johnfwhitesell on Today at 01:42 AM »
At that point, say 2020-2021, ULA will likely have insufficient commercial business to make the business case close...

NASA CRS2 alone is more business for Vulcan then everything announced for New Glenn to date.  Commercial Crew missions are even more valuable then that.  Then they have Delta launches once a year out to 2023, at like 350 million a pop.  Upwards of a billion dollars in revenues a year and we haven't even talked about non governmental customers.  With internet constellations getting added to the existing launch market there should be quite a lot of money sloshing around.  At least some of that constellation business is shunning SpaceX and New Glenn will not be launching in sufficient volume to serve these before their licences expire so they will have to launch on Vulcan, Ariane or something ex-Soviet.  It's hard to see Vulcan not either getting a share of that business or eating up the traditional GTO satellite market while everyone else is serving the constellations.  So between the lucrative contracts they have and the contracts in play they should be launching as fast as they can build.

It feels to me like there is a bit of a self sustaining cycle of expectations in play here.  Everyone knows that reusable rockets are the future.  So at some point in the future, launches of large satellites on expendable systems should stop.  This much is fairly sound logic.  The problem is that because of this long term logic, people become confident in reusable rockets and make bold predictions, which fuels more confidence which fuels more bold predictions.  People are talking like in 2021 New Glenn is going to be a reusable rocket doing dozens of launches.  That's highly improbable.  2025 is a date I would believe for that.  And there are 4 years in between those dates in which other systems are going to be changing as well.
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The S2 re-entry zone is oriented northwest to southeast, aligned for a descending node re-entry.

How long would it take for the initial, approximately 90-minute orbit to "walk" around the globe to have a descending node re-entry over the North Atlantic?
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Advanced Concepts / Re: Realistic, near-term, rotating Space StationT
« Last post by Roy_H on Today at 01:24 AM »
My main argument for a rotating space station is that people can go to work in a weightess environment and then eat and sleep in a normal 1g in environment.

Seems like a high ratio of eat & sleep space compared to zero G space. Why don't you think people will work in 1G environments?
Easily adjusted, if more work space required, just add more modules. I set this design for approximately 240 people. With many more agricultural modules than there are living modules, maybe too many and if so then there could be more living modules.
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The drawing is a work in progress and I have not yet installed the cables or the elevator.

I'm curious to see how you plan to physically keep all of this structure together while rotational forces are trying to tear it apart?
The force is one g. We deal with it all the time we build bridges that can carry loads houses with floors as you can walk across. No more stress than everyday life right here on earth.
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The two large free turning wheels are for hanging cables on to support the outer rim.

So, like a bicycle wheel?
Yes, exactly.
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I did these drawings in Blender, does anybody know how to get rid of these annoying light rays?

Ask on a Blender forum? I'm sure it's a common thing.
I didn't get a satisfactory answer there yet.
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Space Science Coverage / Re: ESA - Gaia updates
« Last post by CuddlyRocket on Today at 01:19 AM »
Another new Gaia discovery that popped up on twitter today: there is a gap in the HR main sequence stars.

So, who's this gap going to be named after? :)
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The drawing is a work in progress and I have not yet installed the cables or the elevator.

I'm curious to see how you plan to physically keep all of this structure together while rotational forces are trying to tear it apart?

That's the trick isn't it? (or one of them, anyway).  There are multiple, layered chicken-and-egg issues with creating a real solution for implementing spin gravity.

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I did these drawings in Blender, does anybody know how to get rid of these annoying light rays?

Ask on a Blender forum? I'm sure it's a common thing.

I use Sketchup/NetFabb to generate my models for 3D printing, so can't help you with the Blender issues sorry Roy.

My news since I last commented on this thread is that I've co-founded a start-up company Exodus Space Systems, and lodged a provisional patent for what we're calling the Deployable Toroidal Array (DeTA).  The versatility of this geometry means we're also exploring multiple non-spin-gravity applications, but perhaps the most exciting one is our method of tackling space debris SDEDI (Space Debris Elimination by Dry Ice).  We're working towards a prototype we can launch - perhaps with Rocketlab USA - which will be about the size of a refrigerator in the range of 100-200kg.  Here's a video presentation we've been showing to those that are interested:



As you'll see, I've identified what I think are 6 separate issues, some or all of which affect previous spin gravity proposals.  We're really trying to avoid huge structures or in-space assembly, and the emphasis is on a "space origami" concept with dynamic stability - elements are solid (no cables/tethers) and either in compression or tension - and with a little work you can get some pretty large deployed spin radii relative to the payload bay it launches in.  Possible to achieve human scale Mars g simulator (25m radii, <4rpm) from a BFR (9m) fairing.

Still very early stages yet, but we're in the process of raising money so we can lodge the full international patent, complete our sub-scale demonstrator and do a zero-g flight inside the next 12 months. Any comments or questions welcome!
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SpaceX BFR - Earth to Deep Space / Re: Elon The Boring Company
« Last post by CuddlyRocket on Today at 01:14 AM »
Any kind of induction charging while still or moving is unlikely, Elon's not a fan on account of the inefficiency of it.

It doesn't need to be induction charging; direct contact by way of a pantograph or similar system at the terminii may well be possilble. Or you can take the individual skate off-line and use the equivalent of a supercharger.

Most likely when the battery gets low, the pod will be automatically routed out of service and then either perform some kind of battery swap with some sort of automated system or simply charge with a supercharger style connection (but one that doesn't require a human to plug in).

Musk did try rolling out a battery swapping service in California, but abandoned it. Not sure if I heard the reason why, but with an even bigger vehicle the mechanical complications may not allow it.

Battery swapping was abandoned because there was no consumer demand for it. As for 'not requiring a human to plug in': why not, if that's the most efficient way to do it? As Elon has discovered on the M3 production line, humans are underrated!
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