From: nospam@127.0.0.1   
      
   On 2/4/2021 1:32 PM, JF Mezei wrote:   
   > On 2021-02-04 05:31, Snidely wrote:   
   >   
   >> Now you're adding additional requirements to the requirement of "more   
   >> than 1 second firing".   
   >   
   > The poit of test firisngs is to test the assembled rocket to ensure the   
   > integration worked well. This is why NASA recently tried to test its SLS   
   > rocket as a hole instead of engines  mounted separately on a stand.   
   >   
   > NASA is in no hurry to get SLS up so is at the "slow" extreme.  SpaceX   
   > is in a hurry and is at the fast extreme and just building these silos   
   > as simple and as fast as it can to test.   
   >   
   > The fact is that the FAA is not amused by SpaceX cowboy attitude of   
   > throwiong things up in to air to see how far they go before they explode.   
   >   
      
   That's your opinion, not a matter of fact. I dispute your   
   characterization. From what I've seen FAA and SpaceX are working closely   
   together, Elon's occasional tweets of frustration aside. The last   
   public, weasel-worded statement from FAA that I saw, I believe was   
   designed to give SpaceX plenty of maneuver room to work together with   
   them on a solution. As one internet scribe put it (and I paraphrase),   
   'This is often the approach the FAA takes publicly to make it known they   
   believe the responsibility for the non-compliance was with the licensee,   
   but in such a fashion as to not try to assess cause or blame.' The fact   
   that SN9 was eventually granted a launch license is proof of that. The   
   whole 'cowboy attitude' meme is a concoction of fiction.   
      
   > The fact that SpaceX can spit out SNxx so fast and cheaply makes it a no   
   > braienr for them to throw them up in the air to see how far they go and   
   > progress after fixing flaws. But eventually, the FAA will likelt tell   
   > SpaceX to either move to central Australia if it wants to develop that   
   > wayl or test before launching.   
   >   
      
   No. That's not going to happen.   
      
   > I was told here that the launch pads don't support long burns because of   
   > all the sand/dirt/debris around and lack of flame trench.   
   >   
   > While launch pad tests can't test the aerodymacis of re-entry/descent,   
   > the later requires as an essential part the lilghting of engines in last   
   > seconds to right the ship as this isn't done with   
   > flaps/ailerons/whatever alone.   
   >   
   > So prior to test the aerodynamics, you need to make sure that your   
   > engines will work and relight for the final phase of flight.   
   >   
   > Falcon9 landings were tested in the ocean with their drone ship.   
      
   No you are forgetting about the Grasshopper tests. The first soft   
   landings of much of what became the Falcon 9 first stage booster from   
   high altitude occurred in Texas at McGregor. Experiments very similar to   
   what is being conducted on Starship, minus the belly flop maneuver.   
      
   Falcon 9 attempts of landing *from orbit* occurred first at sea, but the   
   first successful landing occurred *on land* at LZ-1 (formerly LC-13) at   
   Cape Canaveral, 21 December 2015.   
      
   > Starship is being tested on land not far from populated areas so FAA is   
   > right in having concerns.   
   >   
      
   Of course, but also don't forget Boca Chica is mostly beach. If it were   
   of a high nature of concern, FAA could insist tests must take place over   
   the Gulf of Mexico, which is easily accomplished from Boca Chica. So far   
   that hasn't happened.   
      
   >   
   >> All engines ran fine for much more than 1 second on ascent.  Did you   
   >> notice that?   
   >   
   > As I recall for SN8, there were some concerns about flames within the   
   > engine compartment.  Wouldn't that indicate a leak?   
   >   
      
   Not necessarily.   
      
   > The mission calles for engines to work not only on ascent, but precisely   
   > and quickly light-up in the last second of flight.  This isn't like a   
   > car engine where you can turn the key a seocnd time if the engine   
   > doesn't start on first try.   
   >   
   > The one second test don't test not only the engine relighting, but also   
   > the change and pressurization of the separate tanks used for the landing   
   > burn.   
   >   
   > Consider this: now they have telemetry and debris. Had they don this on   
   > a launch pad with rocket firmly attached, they would have not only the   
   > telemetry, but also the engines they could analyze on why one didn't ligh   
   >   
   Or maybe on the test stand or firmly anchored to the launch pad, they   
   don't fail to relight. What then?   
      
   >   
   > So I have to assume that blowing up Sn7.2 was also stopped until FAA   
   > lifted the "do not test"  order/advisory/paperwork.   
   >   
   I don't assume that. Answered elsewhere.   
      
   Dave   
      
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