An Oxygen-Rich Shutdown Is Still a Shutdown

Dragon pica
An oxidizer-rich shutdown“. That is what SpaceX’s VP of Astronaut Safety and Mission Assurance Ken Bowersox called the premature shutdown during last December’s Falcon 9 rocket.

Since the December 8th launch, there have been persistent rumors that the Falcon 9 had experienced a significant in-flight anomaly. As late as last June, SpaceX maintained that two of the nine engines in the Falcon’s first stage shut down according to plan ten seconds before the other seven and that there was no engine failure.

One individual, Valdor VP Joseph Fragola, contacted NASA Chief of Safety and Mission Assurance Bryan O’Connor about rumors of last year’s Falcon 9 launch. For that, SpaceX filed a defamation lawsuit against Fragola last June. SpaceX recently settled its lawsuit with both parties walking away, an implicit admission by SpaceX that there was no “there” there.

SpaceX only came clean on the Falcon 9’s premature engine shutdown just last month during a meeting in Houston with the ISS Advisory Committee and the NASA Safety Advisory Panel, fully 8 months after the incident. At best, SpaceX has been inaccurate, deliberately or not, in its past statements concerning the performance of the Falcon 9 main stage in last year’s flight. Certainly, SpaceX’s misdirection concerning last year’s launch hurts efforts by those who seek to carve-out a market for commercial crewed space flight.

“There was no explanation or root cause analysis or corrective action for this particular anomaly. This is a relatively troublesome statement not to recognize that a premature engine shutdown was a significant event.” – Charles Daniel, Shuttle and Space Station Safety expert at Valador Inc., Member of the ISS Advisory Committee

Missions » ISS » COTS »


  1. What Bowersox said, but did not make it into the current version of the article, was that there was no premature shutdown of the engine.

    The engines did not fail. The Merlin engine has a robust design that can easily withstand this type of event.

    There was no impact on mission success. The last mission successfully achieved all mission objectives.

    This would be a problem for the long term goal of reusability as engines would need to be repaired before they could be used again.

    However, the issue was easily resolved. To improve the potential of reusing engines, and to make the shutdown process as predictable as possible, SpaceX has made a small change so that the engines will run out oxidizer before running out of fuel.

    SpaceX discussed the issue with NASA and resolved it to their satisfaction months ago. SpaceX completed a full post-flight report on all indications from Falcon 9 flight 2. That report was distributed to NASA officials. NASA personnel were briefed and the situation was explained to NASA’s satisfaction.

    Kirstin Grantham, SpaceX Spokeswoman

    • Kirstin,

      Thanks for commenting on this post and for trying to answer some of the concerns raised in the SpaceNews article.

      I just checked the SpaceNews article and it hasn’t changed materially since yesterday.

      In the claim by Bowersox of an “oxidizer-rich shutdown”, nothing was said of an engine failure, only that the performance of two of the nine Merlins was off-nominal. Engines running oxidizer-rich would be off-nominal. I know two engine engineers who are still scratching their heads about Bowersox’ “oxidizer-rich shutdown” quote–they’d never heard of that.

      In the SpaceNews article, Bowersox is further quoted, “Bowersox added that ‘those temperatures could have damaged the turbines in the turbo pump.’ That presents an obstacle for SpaceX, which eventually intends to reuse the nine Merlin engines that power the Falcon 9.”

      Here are some follow-up questions:

      If an engine turbine’s temperature exceeds design limits, it runs the risk of an in-flight failure. That will cause the rocket to fail, and in a dramatic way. So this isn’t just an issue of having to inspect and repair a turbo pump. This is a possible safety of mission issue. What is the design temperature of the oxidizer turbo pump? What were the recorded temperatures of the oxidizer-rich running turbo pumps?

      With some engines running hot on oxidizer, there is the chance they are using-up oxidizer that the other engines will need, thereby impacting the remaining engines’ performance, at least in terms of running time. On the last launch, how much of the fuel and oxidizer were meant to remain unused vs. how much was estimated remaining at engine shut-down?

      Can you please clarify the statement, “…SpaceX has made a small change so that the engines will run out oxidizer before running out of fuel.” Are you stating that SpaceX will load-up more oxidizer? Or more fuel? Or did SpaceX change the engine controller? If so, was the change one in hardware, software, or a mix of both?

      What was the intended and actual specific impulse of the oxidizer-rich and non-oxidizer-rich Merlin’s during last year’s launch? I ask because an oxidizer-rich running engine will not impart the intended delta-v. That could impact a mission where cargo mass is nearing the maximum limit.

      You discussed this issue and resolved it with NASA months ago? With whom at NASA did SpaceX discuss this issue and when? Brian O’Connor? Charlie Bolden? Before or after Fragola was served with SpaceX’s defamation civil complaint?

      In the Fragola settlement statement it’s claimed that there was a misunderstanding. Could you clarify the nature of that misunderstanding?

      How did SpaceX learn that Fragola had emailed NASA’s Brian O’Connor concerning the Dec. 8, 2010 launch?

      Thanks again for commenting. We look forward to your responses.

      Jim Hillhouse

      • From what I understand in all of this, the engines did NOT shut down because it was running rich, but instead, the engine briefly ran rich during the PLANNED shutdown because fuel was shut off before the oxidizer. Most of your followup questions seem to assume that the engine was running rich through a significant portion of the flight.

  2. Kirstin Grantham September 11, 2011 at 10:25 am

    I mean no disrespect, but from the Space News Article:

    “Valador Inc., was sued in June by SpaceX in Virginia’s Fairfax County Circuit Court. SpaceX brought the suit forward after another Valador vice president, Joseph Fragola, made what SpaceX said were defamatory statements about the safety and reliability of the Falcon 9. “

    “According to SpaceX’s complain, Fragola on June 8 emailed Bryan O’Connor, then NASA’s chief of safety and mission assurance, saying he was trying to verify a rumor that the Falcon 9’s first stage experienced a significant anomaly during its Dec. 8 mission.”

    “I have just heard a rumor, and I am trying now to check its veracity, that the Falcon 9 experienced a double engine failure in the first stage and that the entire stage blew up just after the first stage separated. I also heard that this information was being held from NASA until SpaceX can ‘verify’ it,” Fragola wrote O’Connor, according to court papers.”

    Question: Since you now seem to be acknowledging that such an anomaly occurred, why was a suit filed against Mr. Fragola/ Valador?

    • “acknowledging that such an anomaly occurred”? There is a HUGE difference between an engine did not shut down nominally and “the entire stage blew up”. If Mr. Fragola had said ‘I have just heard a rumor, and I am trying now to check its veracity, that the Falcon 9 experienced an engine anomaly…’ I doubt SpaceX would have sued…

      • SpaceX did sue and then, 2 months later, said it was all a misunderstanding. Sure…but again, what SpaceX is telling people is not matching-up with what others are hearing about the same launch. This is why we hold review boards, so that the truth, and any bad news, can get out and fast.

        Eli, if you’re in a position at SpaceX to know some of the details of what really happened, we’d love to hear from you. On, or off, the record.

        • No, I have no affiliation with SpaceX, I’ve just been following the company, and while I agree that SpaceX should be held to the same standards of any company where safety is a concern, I also feel that there are many people with an axe to grind that will jump on any opportunity to question the company (I don’t mean to imply you).
          With regards to SpaceX suing Fangola, I actually agree that what he did was out of line. He didn’t just say he heard there was an anomaly, which was true, he said he heard there was an explosion, which was obviously not true and I think intended to cast doubt on SpaceX. Even if he truly believed that there may have been an explosion, there was no immediate safety threat since there was not a scheduled launch for some time, so such an inflammatory email based on nothing more than “rumor” was not necessary. I feel he would have been more responsible if he had either waited until he did more research, or simply stated that he had heard there was an anomaly during the launch and that he would follow up. Also, I think “all a misunderstanding” is legal speak for neither party wants to drag it out, as it would have been bad publicity for everyone involved.
          You say above, “That’s not exactly what SpaceX is telling folks up on the Hill”, do you have any sources for this? I would be really interested to read what is actually being said.

          • Eli,
            You say that Fangola should have done more research.

            Fangola contacted NASA Chief of Safety and Mission Assurance Bryan O’Connor stating “I have just heard a rumor, and I am trying now to check its veracity”.

            If Space X is playing straight with NASA, what better way of doing research is there than going to the NASA Chief of Safety and Mission Assurance and asking for clarification?

            Additionally as Hillhouse asked above, how did a personal correspondence between the NASA Chief of Safety and Mission Assurance and Fangora become the basis for a(eventually withdrawn) defamation lawsuit?

          • Fragola also said “I also heard that this information was being held from NASA until SpaceX can ‘verify’ it”, which if true would mean asking the chief of safety wouldn’t do much good…

            It is defamation if he knew the statements to be false and sent the email specifically to cast doubt on the company, which would be a very difficult thing to prove and I imagine is ultimately why SpaceX dropped the lawsuit. The key here is what Fangola’s intent was, whether he truly believed that there was this failure and explosion, or if he was intentionally trying to cause trouble for SpaceX. I believe that it was the latter, where you obviously believe it is the former, and there is only one person who knows the truth. I’m willing to accept that it is possible that he really was just concerned and SpaceX overreacted, but you should also be able to see why there would be motivation for Fangola to cause trouble for SpaceX.

            Its obvious we will not see eye to eye on this, as we are looking from different viewpoints, but I hope we can at least agree to root for the success of the US space industry, regardless of who the players end up being.

            • “It is defamation if he knew the statements to be false and sent the email specifically to cast doubt on the company…” It would be. But we don’t know. Defamation is not hard to prove in this case. And since SpaceX has much deeper pockets than Fragola, if SpaceX really believed in its case, it would have pursued it.

              What in fact did NASA know and when did it know it relative to SpaceX’s knowledge of the Dec. 8 Falcon 9 launch? What did SpaceX disclose to whom and when? Those are the key questions that remain unanswered. SpaceX has given answers that have not in any meaningful way resolved in people’s minds on the Hill what the truth is. But there are serious concerns that there was an attempt to hide.

              I can’t wait for Griffin, Armstrong, or Cernan to weigh-in on this issue during next week’s hearing before the House Space Committee.

          • What and when NASA knew would be easy to prove, but what Fragola’s intent was is not. Like you said, we don’t know.

            The facts of what and when NASA knew on the other hand will be easy (relatively at least) to discern and hopefully will help to answer some questions. I personally have faith in SpaceX and I think we are headed into a new era of spaceflight. I know there are many out there who think that this will not be a positive change, but I think that only time will answer that question.

  3. The biggest concern to me is not that there was a glitch with the Falcon 9 launch. The unexpected is alwasy routine when it comes to new space hardware.
    The issue is that SpaceX and other COTS/CCDev participants are not providing the expected level of transparency that NASA traditionally maintains. NASA’s historic transparency, in contrast with the Soviet space program, has resulted in a great deal of public trust.
    SpaceX has a wide, enthuiastic following, and even among it’s most sincere critics, there is a genuine desire for it to prove successful.
    There is no reason to hide in the jungle for 50 years, like the Japanese soldiers who refused to admit that the war was over.

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