On 10/7/2013 8:05 AM, Ed Kelleher wrote:
At 10:40 AM 10/07/2013, Henry Vanderbilt wrote:On 10/6/2013 7:36 PM, Henry Spencer wrote:Don't remember where I saw it discussed, alas, and a quick search doesn't find anything... The Falcon 9 User's Manual (rev 1, 2009) credits the second stage with "2 restarts" capability, which might have been what I was remembering (although the most plausible reading of that wording would give it a total of 3 starts, not 2).And there's no guarantee that hasn't changed with the new upper-stage engine and other redesign, of course. But in general, multiple restart capability makes a lot of sense for such a stage, providing for more flexibility for complex missions, and more redundancy for simple ones. In any event, that does make it seem very unlikely that the restart test was abandoned after one try because the hardware only provided for one try. Presumably something made it immediately obvious that more restart attempts would be futile. Given that SpaceX has customers both current and prospective to reassure, I expect more detail about what happened and what they do about it will eventually come out. HenrySome evidence of what SpaceX is telling customers. Not conclusive, but interesting. Space News report of 4-OCT-2013 *SES Approves Satellite Shipment for Falcon 9 Launch Despite Questions* http://www.spacenews.com/article/launch-report/37547ses-approves-satellite-shipment-for-falcon-9-launch-despite-questions PARIS Satellite fleet operator SES has authorized the shipment of its SES-8 satellite to Florida to prepare for launch aboard a Space Exploration Technologies Corp. (SpaceX) Falcon 9 rocket despite concerns among insurance industry officials that the Sept. 29 demonstration flight of a new Falcon 9 variant did not meet a key objective. <snip>
A few more specifics in that story, yes - thanks! "Luxembourg-based SES has said it is awaiting more data from SpaceX about why the Falcon 9 v1.1’s upper-stage engine did not complete a second ignition..." In other words, SES doesn't have the details yet either. The story goes on to say that SES is shipping the sat to the launch site anyway because they REALLY want SpaceX as an additional launch vendor.
I gather though that SES is very unlikely to authorize actual launch though until they - and their insurers - have seen the actual stage telemetry and heard a convincing explanation of what went wrong and how SpaceX will fix it. The story quotes someone at their insurer as (anonymously) saying that launching under the current circumstances may well constitute "a material change to the policy" that would allow them to cancel or alter SES's current $200 million, 12%-premium policy.
One other new fact there: "During a postlaunch press briefing Sept. 29, meanwhile, SpaceX Chief Executive Elon Musk said the company had plenty of telemetry data to analyze why the rocket’s on-board computer halted the upper-stage reignition sequence." Note however that this says nothing about where in that sequence the halt came. You might easily assume the halt came on a minor pre-light discrepancy, but it could equally well have been on a major post-ignition departure from nominal. The statement carefully doesn't specify, but the fact that they didn't try again makes the latter seem more likely.
My take: SpaceX will have to satisfy this customer and its insurers before this next launch takes place, and the rest of its customers and their insurers at some point. Chances are more hard data will become public in the process.
Henry
