All Systems Go!

originally posted by: NightFlight
a reply to: StallionDuck

Live coverage is also on DirecTV, Discovery channel 278, starting at 12 noon EDT with live coverage starting at 2 pm EDT, and also on the Science channel 284 with just live coverage also at 2 pm EDT.

Someone with Dish could give the Discovery and Science channel info.

there is a NASA channel on Dish (286)

making note to myself to remind to watch. should be home that day.

a reply to: Flyingclaydisk

APOLLO 12

Launched during thunderstorm - was struck by lightening and suffered massive overload

Crew was able to reset the systems and continue mission

The ionized gases of the rocket exhaust provide a perfect trail for lightening to follow

www.youtube.com...

originally posted by: Flyingclaydisk
a reply to: Zaphod58

Who imposed the "instantaneous window"?

A fifteen minute delay could not have affected their orbit significantly. 45 minutes maybe, but not a miss.

Who established the "instantaneous window"?

NASA????? They've launched manned missions in lightning storms...so why not now?

Can't have a commercial company show up the gubmint!

ETA - Even so, I'm betting money NASA will scrub Saturday's mission too...just cuz.

ETA2 - Apollo missions used to be delayed by hours, days even. Granted they weren't rendezvousing with the ISS, but still, minor corrections would fix the orbits.

I'm probably talking out my ass on this one but it could be the computers they're using on this new capsule are more sensitive than the older ones. Or maybe they don't have any manual controls if the computers fail (I don't know that they did on the shuttle either though).

More than likely they are just being really careful because it would be a massibe PR failure if the thing failed on it's first mission.

originally posted by: ElGoobero

originally posted by: NightFlight
a reply to: StallionDuck

Live coverage is also on DirecTV, Discovery channel 278, starting at 12 noon EDT with live coverage starting at 2 pm EDT, and also on the Science channel 284 with just live coverage also at 2 pm EDT.

Someone with Dish could give the Discovery and Science channel info.

there is a NASA channel on Dish (286)

making note to myself to remind to watch. should be home that day.

The NASA channel is also on Pluto TV, which is a free streaming app available for mobile devices. It's also available through most smart TV devices such as Amazon Firestick, Chromecast, DVRs, etc., if you want to watch NASA on TV rather than from your computer or smart device. In my case at least, the app is included on my Xfinity DVR.

originally posted by: Flyingclaydisk
There's a whole lot of systems on the Dragon / Falcon which piss NASA off, and one of the biggest ones is the escape system (something NASA has never been able to develop properly). The spacesuits should make NASA and David Clarke cringe...they're better.

First of all, NASA wants these commercial crew transports from SpaceX and Boeing. NASA were the ones insisting on it, and NASA were the ones who created the programs and gave Billions of dollars to SpaceX and Boeing to create these spacecraft like the SpaceX Dragon.

SpaceX built this because NASA gave them money to do it. Maybe Elon Musk might have gotten around to a manned vehicle eventually, but it was NASA money (and specifically NASA's COTS and CCDev Programs) that provide Musk with the money needed to build these things now.

Secondly, those aren't space suits. What I mean is they are not pressure suits that could be used in the vacuum of space.

They are more like a flight suit worn by fighter pilots, but with a few additional features such as a cooling system. They can pressurize somewhat in an emergency (again, something like a fighter pilot suit can squeeze the pilot's body), but will not protect the astronaut in space (open space).

a reply to: BrianFlanders

The launch window is determined by orbital positioning and mechanics

ISS is in a high inclination (57 deg) orbit which means launch from Cape Canaveral (28 deg) requires lot of fuel
to reach correct orbit. If miss launch window would require large amount of fuel expenditure to get in correct position

This means possibility of running out of fuel and failing to dock with ISS Russians had several instances of failed dockings
causing mission aborts

a reply to: Flyingclaydisk

I wouldn't doubt that. Betting that Nasa is losing their minds over someone else taking a slice of their government pie. I seriously wouldn't doubt loss of life on this launch or the next to make sure they can hammer that nail in private coffins.

a reply to: StallionDuck

They wouldn't have spent millions in development, or taken the precautions they did if NASA hated the idea.

originally posted by: StallionDuck
a reply to: Flyingclaydisk

I wouldn't doubt that. Betting that Nasa is losing their minds over someone else taking a slice of their government pie. I seriously wouldn't doubt loss of life on this launch or the next to make sure they can hammer that nail in private coffins.

SpaceX developed the Dragon 2 because NASA wanted them to. SpaceX has been getting chunks of money from NASA for the past 10 years to develop and build it -- and NASA is continuing to give them even more money for the next phase of proving the capability of their spacecraft. It would be silly of NASA to pay Elon Musk billions of dollars to develop, build, then test the Dragon 2 and then get mad that they are getting exactly what they have been paying SpaceX for over the past decade.

NASA's CCDev (Commercial Crew Development) Program and the COTS (Commercial Orbital Transportation Services) Program before it, under which SpaceX received a portion of the funding to build the Dragon and Dragon 2, were NASA ideas. Those programs were developed and funded by NASA because they wanted commercial companies providing orbital transportation services for cargo and crew.

If NASA didn't want these spacecraft, why did they pay SpaceX (and Boeing, who also participated in NASA's CCDev Program) all those billions of dollars to help fund the development of them?

27 May 2020 | 14:19 GMT
What It’s Like to Sweat the Launch of a New Spaceship
A former mission controller remembers the last time the United States dared to put humans in a new type of spacecraft—and some hard-won lessons for today

spectrum.ieee.org...

SpaceX instantaneous launch window.

a reply to: Zaphod58

Great article, and it explains the performance issue, but it doesn't explain what the stated danger is. Why not just add more LOX to replace the LOX which boils off?

Is it an ice issue?

NASA had launch holds on the Space Shuttle many times. I recognize the Shuttle boosters were solid rockets, but the External Tank wasn't, and it had nearly 1.4 million pounds of LOX in it, in addition to 234, 000 lbs of Liquid Hydrogen.

a reply to: Flyingclaydisk

If you want to keep your bath warm, you can keep adding hot water to it. But eventually your water heater runs out of hot water and your bath goes cold. If you want a hot bath after that, you have to wait for the water in your water heater to get back up to temperature. Same idea here. They can’t produce the sub-cooled LOX and RP-1 fast enough to keep the tanks constantly topping off.

Space Shuttle didn’t use sub-cooled, densified propellant.

a reply to: nataylor

Okay...I will admit a brain fault here...please explain the difference between LOX and LOX. Liquid O2 is Liquid O2.

What is "sub-cooled" LOX? I am not aware of such a thing. I've worked with LOX a lot and perhaps I am just misinformed.

You have three states, gas, liquid and solid. Secondly, Oxygen, under any circumstances is considered an "accelerant" not a propellant (unless of course you are suggesting just a pressurized gas). So, I don't understand your reference to "densified propellant". Maybe combined with the RP-1 it is, but alone it is just LOX. At least until it is combined in the engine with RP-1 for ignition and thrust. Until then they are kept separate.

So, what am I missing here? I must be misinformed.

Space X is using a lower temperature (10%). Still above the solid state, but only marginally different than the intitial liquid state. (-340F vs -297F). Nothing in this temperature range significantly changes the properties of the gas, one way or the other. The only difference is density (possibly). Storage methods are the same, with perhaps additional insulation properties, but okay.

So...Falcon needs a denser load of LOX. Okay. Back to my question, why not just replenish LOX boiled off, at the same density?

ETA - The tank was designed to hold a full load to begin with, so why not re-fill the tank to the capacity it is designed for ...after the LOX boils off??

Oh, and yeah, I did work for NASA for a while, so I'm not a complete dummy here, but I will admit I am not an expert on the Space X Falcon.

a reply to: Flyingclaydisk
You can have 200° water, or you can have 40° water. Both are liquid, and both are below the boiling point. But the 40° water is denser. You can fit more 40° water in a certain volume than you can fit 200° water.

Same with LOX and RP-1. They can fit about 10% more propellant on the rocket by cooling it far below the boiling point, rather than just under the boiling point.

a reply to: nataylor

Got it, I understand the physics (and physics in general), as I've stated, but see my questions above.

ETA - Water is a bad example, just saying!

originally posted by: Flyingclaydisk


ETA - The tank was designed to hold a full load to begin with, so why not re-fill the tank to the capacity it is designed for ...after the LOX boils off??

Because, as I stated with my water heater metaphor, the system the use to cool LOX and RP-1 doesn’t have enough capacity to keep a constant flow going into the rocket. It’s got enough capacity to fill up the rocket, but then needs about 1.5 hours to “recharge.”

You don't want to cool the RP-1 very much (and maybe this is part of the reason, I don't know). RP-1, like any petroleum product will gel lower temperatures. So, while the LOX may be loaded at low temperatures, the RP-1 is not loaded at that low of temps because it becomes a gelatinous solid and it doesn't flow well. Yes, pressure can fix some things, but not all. Pressure generally increases temperature to remain in a given state, not reduces it.

Good grief...I'm getting into a whole bunch of stuff I haven't been involved in for years.

Whatever...I surrender...you might be right (but I lack the energy to debate it anymore).

You win.

I have one simple question which remains...

Why not load more LOX into the main booster to delay the launch? (a couple hours I could understand, but a few minutes I cannot).

The danger was not explained.

I'm sure there is some reason, but as it stands, "instantaneous" does not compute with me.

That's all I'm saying.