SpaceX Founder Elon Musk is hoping that ‘the third time is a charm’ in his attempt to launch America’s first private industry rocket program.
The first attempt in November was scrubbed due to a tank fill valve that vented unexpected quantities of liquid oxygen. Without enough liquid oxygen in reserve, the launch was scrubbed and rescheduled for December 19th.
The second attempt in December started out with a stand-down due to high winds. When management decided to delay the launch for 24 hours, technicians started emptying the fuel tanks. Unfortunately, a short circuit in the tank vent valves resulted in a vacuum that distorted the fuel tank walls, and launch #2 was scrubbed.
In an emailed press release, Elon Musk of SpaceXwrote:
As previously reported, we traced the problem to failure of an electronic component in one of the first stage fuel tank pressurization valves. Although we have triple redundant pressure sensors and dual redundant pressurization valves, when this component shorted, it caused the valve controller board to reboot, effectively eliminating the redundancy.
This is the first time in 3.5 years of hard testing that we have ever seen this happen. Moreover, the component in question has a cycle life and power rating far in excess of the theoretical load that it should see. To address this specific problem, we are replacing the component with one that has a quasi-infinite lifespan and taking a few other steps that will isolate any issue with this component if it goes wrong in the future.
It is worth noting that we would have caught the problem without any damage to the vehicle if we had entered the final countdown sequence as planned. The sucked in tank damage only occurred because we partly drained the fuel tank due to the hold for high winds.
One thing I love about this start up company is their rapid response to adversity, and the efficiency that comes from having someone on the spot to write the check:
Following the problem on Dec. 19, we flew a whole new first stage to Hawaii via C-5 just in time to catch the barge from there to Kwaj a few days before New Year’s Eve. The new stage should arrive at Kwaj in about a week, whereupon we will switch it out with the damaged unit, which will be sent back to California for repair. The repair is not particularly difficult or expensive, but can only be done properly in a factory setting.
…and they’re damn good at time management:
However, as I mentioned in an earlier update, we are not simply going to address this particular point problem and then merrily jump back into a countdown sequence. Throughout January, the SpaceX team will be doing another full review of vehicle systems, including propulsion, structures, avionics, software and ground support systems. We will be conducting additional engine tests, stage separation tests and avionics tests to once again attempt to flush out any issues. Even if we find nothing, the exercise is worthwhile.
Plus, they have a sense of humor, and aren’t afraid of being ‘on the spot’ innovative:
High winds are not a limitation of the rocket, which is designed to be essentially “all weather” and handle ground winds in excess of 50 mph (watch out for flying coconuts!). The ground winds limitation is actually due to the need to avoid a collision with the launch stand hold down arms, which grab the rocket at the base of the fuel tank, as the rocket lifts off.
To alleviate this problem, we have redesigned the launch stand so that the hold down arms retract out of the way on liftoff, activated by a breakwire. This gives us something very close to 100% winds availability from Kwaj. The retraction force is low, so even if there were an early activation of the actuator, it would not damage the rocket.
Another bothersome problem is the high rate of liquid oxygen (LOX) boiloff. This is not surprising when LOX is at -300F and there is a stiff wind impinging on the vehicle at 85F. To minimize boiloff, we will wrap the LOX tank in low cost cryo insulation attached with velcro straps that tear away on liftoff.
And most of all, Elon Musk always seems to keep things in perspective…
Those familiar with the launch business will know that countdown scrubs are a way of life. It’s often said that the safest time to schedule your vacation is around launch day and that’s true more often than not. Even rockets that have launched hundreds of times from launch pads that are in heavy use have multiple scrubs. Not too long ago, there was a Titan launch that had eleven scrubs and a Delta launch that had six.
Reasons range from hard to avoid technical glitches, like the Shuttle fuel sensor malfunction on its last launch attempt, to silly false alarms. A Titan countdown was once aborted when someone spotted a “bag of suspicious liquid” on the mobile service tower. It turned out that the latrine had simply been a bridge too far for one of the technicians.
Given that Falcon 1 is an all new rocket and is launching from an all new launch pad on a remote tropical island, countdown scrubs in the first few attempts were very likely. As it is, we have had one abort due to a launch pad issue and one due to the rocket. If this next attempt succeeds in getting to t-zero, SpaceX will be reasonably fortunate in the scheme of things.
I’m looking forward to Feb 9th. I have a good feeling about these folks, and count them as a great investment should they ever go public (after the first successful launch I’m guessing).
If you’d like to read more about SpaceX, I recommend these Blogcritics posts:
June 28, 2005 – Space Exploration Technology Corporation – SpaceX
September 9, 2005 – SpaceX Announces Falcon 9 – A Heavy Lift Launch Vehicle
October 8, 2005 – The Space Age of SpaceX
Also posted at VERMONT SPACE
( Let’s Launch! )