SpaceX first launch coverage

I'm listening in on a conference call for the first launch of a Space Exploration Technologies (SpaceX) Falcon 1 rocket. Falcon 1 will carry an Air Force Academy satellite into orbit from SpaceX's pad at the Kwajalein Atoll of the Marshall Islands.

The photo above is from the SpaceX website, with the caption: "Falcon 1 Ready for Launch on Omelek Island."

Launch is scheduled for 1 pm Pacific time.

Mostly I'm hearing a loud typist clattering away, and some indistinguishable hubbub in the background, punctuated with occasional loudspeaker announcements about the rocket's status. I don't know whether they're still on schedule or not.

Also don't know whether I'm hearing the press gathering at SpaceX headquarters in El Segundo, CA and their feed of the launch site, or if I'm hearing the launch site directly. Other reporters on the line with me are trying to raise someone from SpaceX to find out what's going on. Stand by....

--Update at 12:43 pm Pacific--
Larry Williams, VP of International and Government Affairs on the line now from SpaceX in El Segundo...says countdown progressing smoothly. Coming together real well, he says, we have a nice turnout in El Segundo, lots of media. Still on schedule for 1 pm launch.

Diane Molina, SpaceX media contact, tells me I'm listening to El Segundo, not the launch site. I asked her to tell Larry to repeat the status reports coming over from Kwajalein or turn up the gain....

Larry signing off until we get closer to the launch.

--Update at 12:58 Pacific--
Williams answering questions now from a Reuters reporter. Interesting to me, since the L.A. Reuters office was my beat for commercial spaceflight last year; I wrote about Bigelow Aerospace for them, and also helped to cover SpaceShipOne's X Prize winning flights. I switched over the Wired News for news reporting because they pay better and also because Wired News stories stay on Wired.com indefinitely, as opposed to Reuters stories, which disappear quickly and often don't even have bylines.

Williams reporting an email from the launch site saying there will be a one-hour delay. Details forthcoming....

--Update at 1:30 Pacific--
Still no word on what has caused the delay.

Earlier this year I witnessed a Merlin test firing, the first full-duration burn, in fact, of the SpaceX-built rocket engine on Falcon's first stage. I'm guessing the scene unfolding now at Kwajalein is similar to what I saw at SpaceX's test facility in McGregor, Texas. Here's the story I wrote for Wired News on that.

Engineers and managers are hunkered down in a bunker at a safe remove from the rocket. Each has a large flat panel computer screen in front of him/her, monitoring the rocket's vitals. Data to and from the rocket is carried on ordinary Ethernet cables like I have here in my home office. If any of the sensors on the rockets records a problem, it will trigger a halt in the countdown, any time between now and in the microseconds before the engine fires. One of the humans also has a big, red abort switch he/she can hit at any time.

During the test I watched, a faulty temperature sensor triggered an abort in the engine's firing. The engineers were able to determine that the fault lay with the sensor, not with the rocket itself, and they manually restarted the engine, after remotely refueling the craft.

If anything on the rocket itself requires intervention, however, they'll have to scrub the flight for quite some time; safety rules require that no one approach the rocket while it's full of liquid oxygen (LOX), so the LOX will have to be pumped out before fixes are made.

--Update at 1:42 Pacific--
Williams: we're at "T" minus 20.

He's working on getting us on the phone a video feed.

Still no word on what caused the delay, but I guess they've resolved it now.

--Update at 1:50 Pacific--
Someone reporting "T" minus 10

--Update at 1:51 Pacific--
Williams confirming, "T" minus 10 minutes, and holding there for weather. Could be very short, he says, perhaps because of passing clouds.

--Update at 2:39 Pacific--
Williams: Another delay. Technicians have to refill the LOX tanks. One to two hour delay probable. They're still going to try for the 1-5 Pacific time window. Standing by now for an annoucement from Elon Musk.

--Update at 2:54 Pacific--
Williams: launch will be attempted in 1.5 to two hours.

25 people total are on the island. Six people in the launch mission control center. Standing by for more updates....

--Update at 3:18 Pacific--
Robin Snelson reporting on the conference line from El Segundo that she saw five guys around the LOX appearing to be trying to fix something on the fill line that goes to the rocket, and then the video went blank.

Williams: One hour and 15 minutes probably the earliest possible time that the rocket would launch.

They were having trouble getting LOX pressure in the upper stage of the rocket, reports Williams.

Next window would be tomorrow at 1 pm Pacific if today's attempt is scrubbed.

Williams: some issues with filling the LOX tanks. Doesn't know beyond that.

--Update at 4:50 Pacific--
Williams: "We are scrubbing for today. So our next launch window is 9 a.m. Pacific time tomorrow morning."

--Update at 4:54 Pacific--
Williams, with a correction. "We have not got confirmation on what the plan is for tomorrow." Keep an eye on the website for actual times:

http://www.spacex.com/

--Update at 5:49 p.m. Pacific--
Elon Musk has just posted an explanation for today's launch scrub at www.spacex.com:

"What happened was that an auxiliary liquid oxygen (LOX) fill tank had a manual vent valve incorrectly set to vent. The time it took to correct the problem resulted in significant LOX boiloff and loss of helium, and it was the latter that caused the launch abort. LOX is used to chill the helium bottles, so we lose helium if there is no LOX to cool the bottles."

Also:

"We are anticipating rescheduling the launch within a week at the earliest but probably longer as we need to bring in LOX and helium from Hawaii."