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SpaceX Mars / Re: Should the ITS have a launch escape system?
« Last post by CuddlyRocket on Today at 04:18 AM »
If you loose all propulsion in an airliner you will most likely die.

That's not true. In many such cases the pilots manage to re-start an engine. Where they do not, most successfully glide to the nearest runway (the record is 65 miles). Even when they can't reach a runway, many successfully land elsewhere or ditch on water (e.g. Captain Sully on the Hudson river).
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[Steps up on soapbox]
Been stewing this over for the last few days. I am very sad to see Dragon's propulsive landing be cancelled, not because it was sexy or anything like that. It is because like Musk said back at  the D2 Reveal: "This is how spaceships are supposed to land". I believe that with all my heart - I *always* have believed that. Splashdowns were done because back in the day we didn't have a clue how to do anything else. To go back to them 50 years later as the primary recovery is so retro, so 1960's, so chickenshit. We have perfected propulsive landing on Mars for Pete's sake! The Soyuz actually uses it for the final seconds before they hit the ground. Legs coming out through the heatshield scares them? Where are the men who designed Big Gemini with a crew access hatch through the heatshield? NASA actually approved that design. We learned how to do and perfected propulsive landing on the Moon with crew onboard. Remember the LM? Yea, propulsive landing. Now this. What the hell is NASA thinking? It feels to me like they put on their brain-dead hats and told SpaceX to delete it. No guts. No forward thinking. Absolutely no desire to innovate! No wonder we spent 30 years going around in circles. There aren't any forward thinking people in leadership position at NASA anymore. As far as I am concerned there isn't any leadership at all at NASA anymore. Everybody is afraid of their own shadow. They remind me of the cowardly lion on the Yellow Brick Road. The NASA I grew up with is dead and gone. The NASA I was proud to serve doesn't exist anymore. Instead all we have is this shadow thing.
[Steps off soapbox]

Too many red herrings to even address...

Yes, splashdowns were done "back in the sixties"...when our space program was at its peak. Cars had wheels then too. Are wheels now outdated?

Propulsive landing on the moon...yes, in a very limited gravity well, not like Earth.

Propulsive landing on Mars...yes, but not with crew at risk.

Heat shield crew hatch? Yes, but it never was allowed to fly, and was never revisited for future projects.

NASA isn't brain dead, and they are not forgetting that Challenger and Columbia could have sunk the manned space program if people believed that NASA was reckless.

Reliability is not a dirty word. And proven technologies are not bad either. Soyuz is the most successful spacecraft ever...yet it is using "old technology."  America has been grounded several times over the years, several times for multiple years, in its quest for the newest...yet Some variant of Soyuz has flown through all of them, even carrying America back into space on the heels of its (temporary) failures. NASA is proving it is not afraid to learn from history, from its past mistakes, and yes, even from the Russians. That is not brain-dead, that is smart. Very smart.
 

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 It's not so much being on the plane as what happens if it flunks the test.
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General Discussion / Re: 2017 Solar Eclipse - North America
« Last post by Nomadd on Today at 04:12 AM »
 Casper, Wyoming.
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The Mystery Of The Space Shuttle In That Simpsons Episode Where Homer Went To Space


Did they use "disguised" Hermes (as "Corvair") because of too recent memories of Challenger?
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SpaceX Mars / Re: 9m ITS Development Updates and Discussion Thread
« Last post by livingjw on Today at 03:55 AM »
... Tank pressures will be designed for about 30 psi differential, so we know the thickness and weight based onmaterial used. Al/Li tanks will weight about the same as F9 tanks per unit volume. Carbon Composite tanks will be about 15% lighter per unit volume.

If correct, that's actually kind of shocking. CC doesn't give vast mass reductions. That does argue for Al/Li if they can't solve CC easily...

Theory says it should be 30% lighter, but non-optimums tend to reduce it considerably. 15-20% savings should bracket it.
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Missions To The Moon (HSF) / Re: About reusable LM
« Last post by A_M_Swallow on Today at 03:46 AM »
My personal opinion about how astronauts will refurbish some sort of reusable LEM is that they will use a sort of "space garage" in low moon orbit. The mission would likely go something like this- CSM lifts off, and heads to the moon unencumbered. It than rendezvous with a small station that basically just has a hub, a area for refurbishing the LEM, and a docking port. So anyway, they go to the pressurized area that is essentially a large airlock. They refurbish the LEM unencumbered, and depressurize the airlock and take the LEM down to the lunar surface. They then head up, dock with the station, and head home.  Just my two pence.

Propellants are high fire risk and can be poisonousness, so the landers will be kept in vacuum. Reusable landers will have to be designed to permit the replacement of rocket engines and legs using robotic arms. The major components will have to be screwed together rather than welded. Although welding can be used within a component.
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SpaceX Mars / Re: 9m ITS Development Updates and Discussion Thread
« Last post by Lar on Today at 03:45 AM »
... Tank pressures will be designed for about 30 psi differential, so we know the thickness and weight based onmaterial used. Al/Li tanks will weight about the same as F9 tanks per unit volume. Carbon Composite tanks will be about 15% lighter per unit volume.

If correct, that's actually kind of shocking. CC doesn't give vast mass reductions. That does argue for Al/Li if they can't solve CC easily...
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Space Science Coverage / Re: Exoplanets And Stars Thread
« Last post by Alpha_Centauri on Today at 03:45 AM »
Super-Pandora? Candidate Neptune-sized exomoon potentially orbiting Superjovian Kepler-1625b.


HEK VI: On the Dearth of Galilean Analogs in Kepler and the Exomoon Candidate Kepler-1625b I
https://arxiv.org/pdf/1707.08563.pdf
Quote
Finally, we have briefly highlighted our identification of an exomoon candidate in the Kepler-1625 system, for which we have secured a follow-up observation with HST. This candidate has passed a thorough preliminary inspection, but we emphasize again our position that the Kepler data are insufficient to make a conclusive statement about the existence of this moon. Only after the HST observation is made [October 2017] should any claim about this moon’s existence be given much credence.
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SpaceX Mars / Re: ITS Development Updates and Discussion Thread
« Last post by livingjw on Today at 03:44 AM »
Or they could decide to use the Raptors as they are and just stretch the BFR as thrust is increased.

Just like Falcon 9.

The Raptor as it is now is 1/3rd the needed size. You are going to need the full size Raptor.

John
Merlin 1D is now capable of 3x the thrust of the original Merlin engine.

Should have said the Raptor is at 1/3 the needed thrust. Will need about 3 times that much. My impression is that the current demo Raptor was already at pretty high pressure. They will have to grow the engine. That's all.

John
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