SpaceX News

[ladajo]

Or for the transoceanic flying boats to stop for fuel and end up stuck a few days at barren little atols.

Growing pains. They are far from polished, and deep into the active experimentation (Kolb) learning method.

[Diogenes]

It's an issue I've mentioned before. Satellite launchers can understand a window of a few weeks to get optimal results, but when you hit the bigger market, people who schedule time off work for their space vacation, used to airlines running in all but the most severe weather, you're going to have to vastly improve your ability to launch on time.

I don't get the LOX thing though. Are they still working on the process for that? I'd have thought they'd know how long fueling the rocket takes for a while now.

They are now pre- chilling the fuel and oxidizer to fit more fuel into the same tank volume and I guess that process still has some minor issues.

I'm betting the issue is with the fuel. I assume you have to cool the tanks inside the rocket before you can get a maximum fill, and oxygen that absorbs heat from the tank can be simply boiled off.


Fuel that absorbs heat from the tank does not boil off. You will find that as you cool the tank, you heat the fuel, and unless they have some sort of circulation system built into it, once you heat the fuel, it simply stays in the tank and creates a floor for the temperature beyond which you cannot get it to go.



But i'm just speculating. Perhaps their filling system does recirculate fuel in and out of the tank to maximize coldness.

[hanelyp]

Should be entertaining at a minimum. Touchdown? Splash? Splash with Boom? Touchdown with Boom? Just Boom?

Hopefully not a "touchdown with boom + Sink"!

My impression is the barges are solidly constructed with nicely armored decks.

[ladajo]

I guess we might find out on Sunday.

[paperburn1]

But while the rocket industry has decades of experience dealing with "normal" liquid oxygen at temperatures down to -300 degrees F, keeping the Falcon 9 Full Thrust's fuel at the required -340 degrees F has proven much trickier. Even just keeping the fuel in the F9FT's tanks longer than tens of minutes lets it warm up too much. So now, the fuel is loaded in the last minutes of the countdown.
Those problems delayed the pre-launch static fire test in December and led SpaceX engineers to call off Wednesday's launch attempt half an hour before launch and minutes before the webcast was to have started — with a 40 percent chance of no-go weather then, the fear appears to have been that the odds of a weather delay after fuel loading were too high.
The late fuel loading was where things went wrong Thursday. As the clock ticked down from T minus 2 minutes, engineers on the countdown audio net requested a hold at T-1:40. That was quickly followed by an abort call from the launch director — even though the launch had a nominal window of around an hour and a half, Wednesday's apparent fear became Thursday's reality: a halt that late in the countdown wouldn't leave enough time to re-chill the fuel to the required, densified temperature.
So it was not a fuel loading problem but a launch delay in another department that would not allow enough time to rechill the O2 to allow a complete mission.

[paperburn1]

This is an interesting paper on chilled fuel but it just mentions RP-1 and focuses on H2
http://ntrs.nasa.gov/archive/nasa/casi. ... 033847.pdf

From what people stated in the forum it give about a 15 percent thrust advantage. More than enough to justify the extra cost and complexity . Merlin 1D already had the highest T/WR of any production liquid-fueled rocket motor so this has to have been the plan all along. Robust engines and robust fuel.
One rumored reason why is the current first stage is reported to be at the very limits of simple trucking on the US Interstate system. They need to be able to legally and safely drive it from Hawthorne, CA to McGregor, TX, and from either to Cape Caneveral, FL. Based on those roads, they are loathe to stretch the first stage much further to avoid hitting those limits.

[paperburn1]

Three cups of coffee but still able to type.
Lets jump on the what if boat for a few seconds. If Spacex is able to recover on a barge that would eliminate some transportation problems. And if you did build a plant in Texas what would be the cost of "flying" the first stage out to Florida or back from Florida for your next launch. or even refueling on the barge to send it home again. (this assumes a huge amount of re-usability)

[D Tibbets]

First stage size, both length and diameter is limited if highway mobility is the limiting factor. If as said, high reusability is possible, then alternate transportation may minimize size concerns. Produce a 18 foot wide first stage in California, load it on a ship ant transport a batch through the Panamal canal to Florida or Texas. Reuse at the launch site would decrease the cost per flight for the more expensive initial transport.

How did they transport the Saturn first stage?. Was the shuttle external tank all barge transport from Louisiana? Can a C-5, C19, super Guppy, or Russian transport handle the current F1 first stage length? Perhaps Spaxe X could acquire the defunct Sea Launch ship at a bargin price.

Dan Tibbets

[paperburn1]

The first two stages were so large that the only way to transport them was by barge. The S-IC, constructed in New Orleans, was transported down the Mississippi River to the Gulf of Mexico. After rounding Florida, it was then transported up the Intra-Coastal Waterway to the Vertical Assembly Building . This was essentially the same route which would be used later by NASA to ship Space Shuttle External Tanks. The S-II was constructed in California and thus traveled to Florida via the Panama Canal. The third stage and Instrument Unit could be carried by the Aero Spacelines Pregnant Guppy and Super Guppy, but could also have been carried by barge if warranted. Given the fact that the third stage 58 feet 7 inches tall with a diameter of 21 feet 8 inches was carried by the Guppy The first stage from SpaceX could fit nicely inside the craft.(43 ft) height, (18.1 ft) diameter
Side note the Apollo carried ten times more weight to LEO than the current SpaceX can carry.

[Skipjack]

Side note the Apollo carried ten times more weight to LEO than the current SpaceX can carry.

Wasnt reusable and cost a lot more.

[paperburn1]

True

[Diogenes]

Range fault. Are they going to launch or not?

[Diogenes]

Nope. Abort. Another D@mn.

[paperburn1]

FRACK

[Skipjack]

Some Florida hick drove his boat into the restricted zone