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Space Policy Discussion / Re: Trump Space Policy Directive 1
« Last post by john smith 19 on Today at 02:01 PM »
By Marcia Smith | Posted: December 10, 2017 11:04 pm ET | Last Updated: December 10, 2017 11:06 pm ET

President Trump will sign Space Policy Directive 1 at 3:00 pm tomorrow at a White House ceremony.  The directive apparently will make a human return to the lunar surface part of U.S. space policy.

Discussion of implications for, and current status of, Bridenstine’s confirmation:
I started a thread  around the time it was known Trump had won asking if anyone had any idea what his views on space were.

It seems we now have an answer. 

The inside-DC gossip is that the above has been the crux of an argument between the White House and NASA. NASA has been trying to argue that the Deep Space Gateway (which they may be renaming to put "Moon" into the title) answers the policy directive, but people over in the executive branch are saying "No, we mean the surface of the Moon."

I can totally see the NASA perspective on this--administrations come and go, and do they really want to get all worked up on designing a lunar surface architecture when a little over three years from now a different administration could say "Forget that stuff"?
But "Deep Space Gateway" doesn't sound very Moon specific, does it? Now something like "Cis-Lunar Deep Space Gateway" does sound more in keeping.

Except it seems that won't cut it if the WH is really saying "We mean the lunar surface."
I think that's a bit more specific from the White House about space than we've seen for some time.  :(

I admit I'm not really convinced it's worth the effort. Long duration testing could just as easily be done on the ISS, or a "free flyer" near the ISS before going to Mars IMHO and there are a number of issues that it would be better finding out about than going to the Moon (like radiation and zero-g adaptation mitigations for deep space flights in general).

But here's the real question.

When (and how much) money is Congress going to appropriate for these tasks?

Allocation without appropriation is meaningless.  :(

How much are Congress putting on the table for this?
Any good picture for the Sooty?
ISS Section / Re: Expedition 54 Thread
« Last post by theonlyspace on Today at 01:50 PM »
Is there a English translation version of the press kit?
Space Policy Discussion / Re: Trump Space Policy Directive 1
« Last post by john smith 19 on Today at 01:46 PM »
Wrong. The guy you have to blame is named Nixon, not Obama. Nixon is the one that steered the USA away from the Moon, all the way back to LEO. And once the USA was stuck there, courtesy of the space shuttle and the space station sucking the NASA budget dry, there was no real chance of going back into deep space.
Say what you like about 'ol TD but (sadly) he sure did know how to hold a grudge.
SpaceX Mars / Re: Will SpaceX use NASA Kilopower Nuclear Reactors?
« Last post by speedevil on Today at 01:38 PM »
It's only when you'd don't have it that you realize just how big an enabler of large engineering projects a large, ready source of energy is to making them happen. For example heating Silicon to its melting point (about 1450c) is every energy intensive but its heat of fusion is huge so getting it that 1 degree over the line to liquid Silicon doubles the energy bill at least. That's why you need a very big solar array already to make more of them on orbit for SPS, or anywhere else for that matter.

I note that launch to Mars surface costs $130/kg or so. (BFR, 2016)

Picking the first more-or-less suitable cell off alibaba gives me this 3.5W cell for $1.7.

It produces 3.5W, and weighs 5g.

For $130 or so, you can transport the $360 worth of cells to Mars, where they will produce about 350W peak, and perhaps 100W average in a good location.

If you are claiming that it's worth it making cells on Mars, you are also implicitly assuming that it is considerably cheaper to make cells on Mars than on earth.

Which seems a rather extravagant claim.

The cells picked were on the first page of the listings for Solar Cell, the first bare cell. Somewhat thinner cells are coming onto the market, and thin film cells may be considerably lighter.
Suborbital Missions / Re: North Korea missiles
« Last post by VernierLover on Today at 01:37 PM »
HS-15 is about 50 percent of a Cosmos-3 class launcher, so it would be limited to payloads to low orbit of 500 - 700 kg. Most recon birds go to very high inclination orbits, and that reduces payload further.

If Kwangmyongsong 3-2 and 4 orbit is the targed then at minimum 250 kg so 50 more than 4 and 150 more than 3-2.

Right now, NK has problems just getting a small satellite to work, let alone a sophisticated recon sat.
What problem? It works and spatial resolution is good enough to spot aircraft carrier.

As always, I am talking about near term, not in that future where we are all living on Mars, and NK has an SS-18 class ICBM.

It is far more likely to see North Korean on moon before first human lands on Mars.
Why wouldn't NASA crew flights switch to Vulcan as soon as it's available and certified for HSF? I see little point in waiting for Atlas V to be retired, and if Vulcan is that much cheaper ULA will probably try to switch asap.

Why are they buying sufficient RD-180s to last well past the 2022 deadline/embargo?  Jim says transition will extend until mid-2020s.  Seems that they'll use the remaining inventory for civil flights if NSS become off-limits in 2022.

They need RD-180 to satisfy all customers that demand flight heritage: NASA HSF, high priority NSS, nuclear materials launch, etc.

I think the latter two will take longer than NASA HSF, to both to certify for/actually get Vulcan flying those missions.
Quite the opposite, Bruno said Centaur III will be used for all remaining Atlas flights.

Sorry, should have phrased that better. Is it confirmed that Centaur III will not fly on Vulcan?
If we consider reusable rockets, the F9 uses the thick atmosphere to slow down. What’s the fuel penalty for F9 to land at 19,000 feet?

And I always thought the point of Kilimanjaro was to rocket sled up the slope and launch already at some speed.

I'm interested if an upper-stage with perhaps 3 or 5 engines would gain any useful ISP improvement (on the way up) with a higher expansion-ratio* central landing engine, and/or any engine mass reduction** that might end up in an improvement in mass fraction.

*enabled by a high altitude landing pad
**enabled by better T/W after staging. i.e. all engines thrusting for longer after staging, instead of just the vacuum engines. Might this allow the engine to be slightly downsized?
And what constrains landing engine expansion ratio, landing air pressure or 'effective air pressure' during supersonic retro-propulsion?
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