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Space Science Coverage / Re: Comm Relays for Interplanetary Probes
« Last post by Star One on Today at 06:23 AM »



However, MO is getting old and hitting more and more safe mode problems, so we do need to look at replacing it at some point.  MRO all by itself will be a little hard pressed to cover all relay needs, though it can do a lion's share of it, if need be.  Whatever replaces MO as a relay, though, is going to have a robust science package, or it won't fly, either.

Trace Gas Orbiter is going to have relay capability.

What's going on now is that NASA has identified a gap in relay capability and they think they need to plug that. This is not some big decision that Mars relay in and of itself is a major mission--it simply supports the science missions at Mars. And in fact if that science mission changes, the relay requirement can shift too. For instance, if Mars 2020 slips by two years, then the requirement for data relay will slip with it.

Here's what the decadal survey had to say about the issue:


"Mars Telecommunications
The addition of a relay payload with standardized protocols to each science orbiter provides an extremely cost- effective means for establishing a Mars orbiter relay network. Maintaining redundant relay assets whenever relay services are required is a goal, and the key to achieving this goal is attaining a long operational lifetime for each orbital relay asset. NASAís Deep Space Network remains a critical part of the Mars exploration infrastructure. The continued development of onboard data-processing methods can alleviate mission bandwidth constraints for near-term missions. In the longer term both orbital and landed missions will greatly benefit from optical communication technologies."

Not forgetting that the next ISRO mission to Mars should also have relay capacity as well.
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Quote from: Rodney Brooks
the authors analyze 95 predictions made between 1950 and the present on when human level AI will come about. They show that there is no difference between predictions made by experts and non-experts.  And they also show that over that 60 year time frame there is a strong bias towards predicting the arrival of human level AI as between 15 and 25 years from the time the prediction was made. To me that says that no one knows, they just guess, and historically so far most predictions have been outright wrong!

This is what technology looks like in infancy.

Interesting paper, but I would rather say that this is what technology looks like in maturity, as this is what is happening in many fields: small, quasi-logaritmic improvements, and nothing qualitatively new at the horizon.
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It just so happens that LM build DC for SNC.

I didn't quite understand that post. We seem to moving from 4 letter acronyms to 2 letters.  Perhaps in the future, we can economize further by using just one letter for everything.
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In-Space Hardware Section / Re: Arduinos and Raspberry PIs at ISS
« Last post by Danderman on Today at 05:53 AM »
There is going to have to be an optimization process to determine how many Pis vs Arduinos can be hosted.

Another path is to look at the Intel Galileo board to see if it could perform more robustly in orbit.



Don't forget other boards such as the Beagle Bone,TI Launchpad,Gumstix,Freescale's QorIQ based boards,and the MIPS Creator CI20.
There is going to have to be an optimization process to determine how many Pis vs Arduinos can be hosted.

Another path is to look at the Intel Galileo board to see if it could perform more robustly in orbit.



Don't forget other boards such as the Beagle Bone,TI Launchpad,Gumstix,Freescale's QorIQ based boards,and the MIPS Creator CI20.
There is going to have to be an optimization process to determine how many Pis vs Arduinos can be hosted.

Another path is to look at the Intel Galileo board to see if it could perform more robustly in orbit.



Don't forget other boards such as the Beagle Bone,TI Launchpad,Gumstix,Freescale's QorIQ based boards,and the MIPS Creator CI20.

The lesson I learned from Nanoracks is to choose a standard and stick with it.

So, it may be the case that we can only go with one of these microcontrollers, with Arduino maybe being it. Remember, there are integration costs for any new system, so choosing more than one has a high marginal cost.

I would be happy to be proven wrong on this, however.
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Quote
The Falcon-9 with the with an aeroshell that landed a folded up Blackhawk and crew/soldiers was, I thought a nice attempt at addressing the issues

WTF ??!!
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There is no "SLS line item" or anything like that in a budget. Just like there wasn't for Constellation.

As I'm writing this I'm looking at the "FY 2016 PRESIDENTíS BUDGET REQUEST SUMMARY" for NASA, and within the the Exploration section, Exploration Systems Development sub-section, there is a line item for "Space Launch System".  So yes, there is an SLS line item.  There is one for the Orion/MPCV too.  And yes there was a line item for the Constellation program.

Quote
It got cancelled - and lo and behold - a new project was found for the contractors and NASA centers. When/if SLS goes away, the people that have a stake in it in Congress are not going to suddenly decide that they aren't interested in securing funding to the contractors or space centers in their district anymore. They will continue to receive funds for whatever new project arises.

This is a completely separate point from what I was talking about, and yes, and a cancellation of the SLS and Orion would be resisted mightily.  But it's hard to predict what the politics of the day will be, and it really depends on what "vision" takes hold in the minds of the powers that be at that moment in history.

But since you mentioned it, if it's decided that we really can't afford to support a no-less-than-every-12-months SLS flight schedule due to the overall cost it requires (SLS + missions and payloads costs), then how much more can the SLS and Orion/MPCV shrink?

Derate the 70mT SLS and you end up with what the Falcon Heavy can handle, which should be flying frequently by the time the next President is weighing their options.  And by that time SpaceX should have announced their plans for the Raptor powered BFR, and the handful of politicians that actually care about money in Congress will be able to point to the private sector and ask "why does the government need to have it's own rocket?"

Now if Elon Musk is ready for that question, he will have already been floating his plans for going to Mars and suggesting different options for how NASA could ride along.  He could suggest it as a public-private venture, where he takes most of the risk.  Could happen.  Might not.  We'll have to wait and see.  But if it did...
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General Discussion / Re: Plausible sci-fi books
« Last post by meekGee on Today at 05:35 AM »
Quote from:  Andy Weir
I want to give a shout-out to a fellow nerd named Kenny Ray.

When writing The Martian, I was as scientifically accurate as possible. I even worked out the orbital trajectories that they took to get to and from Mars. I had to write software to help me work out a constantly-accelerating orbital path. I also had to find a launch window such that Earth and Mars were properly positioned.

So I had to pick a real-world date for the launch of Ares 3. I never specifically tell the reader any dates, but I had a spreadsheet to tell me the actual date of each sol. And of course everything that was date-sensitive is accurate (like transmission times, etc.)

Kenny was able to back-calculate the actual dates from information in the book. He emailed me his findings and he was absolutely right. So, for being the first person to work that out, he gets a free signed copy of the book.

For the curious: Ares 3 launched on July 7, 2035. They landed on Mars (Sol 1) on November 7, 2035. The story begins on Sol 6, which is November 12, 2035.

Well done, Kenny!

+1 on "The Martian", and this quote is beyond epic.

A note on "The Mote" - there's this random passage where they describe how the crew was preparing to enter orbit, so had to reconfigure the ship from "down is aft" of powered flight to "up is out" of spin - part of space-faring routine.  Nice touch.

And of course the first contact sequence, which is one the most exhilarating descriptions in Sci-Fi, and yet is 100% believable.

I recommend  both, and very importantly, read the two mote books in their correct order. 

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http://www.wsj.com/articles/BL-DGB-40041

Quote
SpaceXís Valuation Rockets to $12 Billion With Google Investment

SpaceX now ranks fourth on The Wall Street Journalís list of billion-dollar private companies, securing a $12 billion valuation.
>

I'm not sure I would have taken up that deal if I were google.
12 billion is a hell of a lot. If they launch 10 times and launch a couple of dragons as well, they have a yearly revenue of a billion. This is already stretching their revenue expectations for this year. So their valuation is 12 times their revenue? How many companies outside of websites have such a valuation?
Airbus group (note they make a couple of planes, fighterjets, helicopters and missiles as well) has a valuation of only 50B.

SpaceX just got handed a shitload of money. Which of course is great, rather see Google wasting it on SpaceX than giving it to people that try to make an algorithm to present me the best personalized add on my screen.
Because the Constellation could make $12 billion profit in a single year, easy, if (IF! If, if, if!) it is deployed successfully to the scale Musk has talked about and SpaceX remains solvent long enough for them to build up the subscriber base (which seems likely as SpaceX is fairly diversified--well, more than Iridium was--and seems likely to dominate the commercial launch industry as well as being well-capitalized and starting up in an era of low interest rates).

$12 billion in profit in a single year is a pretty big if (at least 1 more if than you listed :) ). But you dont need that really.

We've done this before, but SpaceX is aiming for more than 10 launches per year. Even conservatively in 2015-2018, with 3-4 pads but no "revolutions", they should be doing 15-20 launches per year and 6-8 dragons between Crew & Cargo (and DragonLab????).

That's a lot closer to US$2 billion in revenue (20*$80 = 1.6 billion, 6*$70 = 420 million). Operational margins (before investing in R&D, etc) might be 20% giving them US$400 million a year. Now all of that is getting dumped back into new projects and expansions, but a 30x valuation isnt unreasonable for a company that is growing exponentially.
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Look, quotes like this need to be taken in context: airline-like operations is the goal, not just a simple extrapolation of current launch vehicle operations. SpaceX is decades away from that.

Just keep in mind that it was barely "decades" between Wright brother's first flight and airline-like operations....
(Think of bomber squadrons in WWII)

I betcha by the time the mega-constellation if being launched, (some 50 flights per year just for that), reuse will be routine, you'd be able to call the operation "airline like", even if the U/S is still expendable.
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Same here.  The EBay units I've got are #201065780928 and #131442703325 so far in case anyone want to try the same system.

I've decided to try and live up to my screen name and throw my lot in with the replicators.  I have a few questions before I kick off my effort:

1) Why did you decide to go with #201065780928 rather than a frustrum of a cone?  The #201065780928 part looks more like a rectangular slit shape rather than a cone shape.
2) How do you plan on hooking the MA86751B X band oscillator up to the waveguide assembly?
3) It looks like the MA86751B X band oscillator is tunable from 9.9 GHz to 10.6 GHz with power output levels from 10 mW to 100 mW powered by 9-10 Volts DC.  Did you pick this particular oscillator for a reason?
4) Do you expect there to be a resonant frequency within the 9.9 GHz to 10.6 GHz frequency band?
5) Do you plan on putting a dielectric toward one end of the waveguide assembly?
6) With what material do you plan on capping each end of the waveguide assembly?

Although I direct this friendly set of questions to Notsosureofit, Mulletron, and others who are attempting replications, I welcome any forum members to chime in with recommendations or insights.  Can you imagine what would happen if the effect can be shown on such a small scale?  It could cause some ripples and raise a quite a few eyebrows around the world.

It doesn't look like that Gunn oscillator (the MA86751B X band oscillator) has a varactor diode.   That would make it difficult to tune.
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