SpaceX And/Or Rocketry In General

archae86
archae86
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The SpaceX video regarding

The SpaceX video regarding their Earth-to-Earth long-range city-to-city transport with 30 minute flight times is pretty thrilling.

It may well be technically feasible, and just possibly you could find enough passengers willing to pay high enough fares to make it pay.  But I'm profoundly skeptical in the "getting permission" realm.

1. It is going to use a lot of fuel per passenger mile.  The political sensitivity of starting a major new transport method for the elite which burns so much extra fuel to get there ten hours sooner would be tough in several countries.  (Helicopters or tiltrotors come to mind)

2. It going to be very, very, noisy.  While the movie suggests launching sites close off-shore at  New York and Shanghai, I seriously doubt they would get permission to make Saturn V class racket anywhere near that close in.  Farther out would hurt journey times, and push toward faster but more expensive local shuttles than the stylish high-speed ferry shown in the video.

3. Safety.  Commercial air travel kills people, but the crash rate per flight is staggeringly low by the failure rate standards of any kind of rocket I can think of.  Even if I suppose that SpaceX can grind the loss rate low enough (which I doubt), I can't believe the regulatory authorities would accept a certification regime that could actually get executed any decade soon.

Pity, it looks really pretty, and SpaceX badly needs a paying commercial application for the big rocket.

Long-range aviation has been flying at the speed of the 707 for many decades now, and the last two tries at going faster (SSTs: including Concorde, Tu-144 and 2707, and the just barely subsonic Boeing Sonic Cruiser) were either commercial failures, or never got built because people figured out they would be commercial failures before they cut much metal.

 

 

AgentB
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For those who missed today's

For those who missed today's Falcon Launch and recovery SpaceX here

Anonymous

recovery is around 29:34

barge landing is around 29:34 minutes into the video.

thanks for the link

archae86
archae86
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Another stunningly accurate

Another stunningly accurate landing.  But get this, the ever more ambitious Elon says that extremely accurate propulsive landing seems well enough in hand that they plan to design the next one without legs--as it is intended to land by nestling back into the launch mount.

He did not say how big a mismatch between intention and reality the mount/vehicle combination would be designed to tolerate.

While punching a hole through the deck of one of the barges during a landing failure was pretty cheap, having a serious event at the actual launch location could get rather expensive, and delay repeat usage.

The energetics would seem to favor building extra landing locations to handle launches needing more oomph that the full return plan allows.  On the other hand the first stage of BFR is so large that transporting it back for refurb/reuse would be a rather more ambitious undertaking.

 

AgentB
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archae86 wrote:The energetics

archae86 wrote:
The energetics would seem to favor building extra landing locations to handle launches needing more oomph that the full return plan allows. 

If refuelling cost are trivial, then fly back to launch site may make more sense, or position launch sites around the globe, and land at the next stop.  The take off at sea seems to be the future for BFR.

Anonymous

archae86 wrote: they plan to

archae86 wrote:
they plan to design the next one without legs--as it is intended to land by nestling back into the launch mount.

Interesting.  But why?  Is it being suggested that a returning 1st stage nest itself in a "hole", be refueled and fly again.  I don't think so.  The 1st stage under carriage still needs to be cleared for flight along with other considerations.  This implies removal and examination so I don't really see any advantage to the proposed recovery system other then for barge landings where the returning first stage if nested would provide for more stability in rough seas then the current tripod system.  

archae86
archae86
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robl wrote:archae86 wrote:

robl wrote:
archae86 wrote:
they plan to design the next one without legs--as it is intended to land by nestling back into the launch mount.

Interesting.  But why?  Is it being suggested that a returning 1st stage nest itself in a "hole", be refueled and fly again

Just so, actually.  The launch cadence called for at the peak of launching passenger ships and fueling them for a Mars transfer opportunity is extraordinary.  The ambitious plan (maybe notion is a better term than "plan" at this point) definitely has the vehicle flying again well under a day from landing--eventually.  So also is the implication of the newer notion of offering regularly scheduled city-to-city passenger service here on Earth.

As you suggest it seems hardly likely this will be the starting point.  I, personally, expect that LZ-1 will at some point find a compatible mount installed, so that early landings can be carried out farther away from high-cost infrastructure.  Elon may be shopping for a Really Big Crane one of these days, also.

 

Gary Charpentier
Gary Charpentier
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Why? mass.  Landing legs are

Why? mass.  Landing legs are heavy.

AgentB
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Echostar 105 / SES-11 Launch

Echostar 105 / SES-11 Launch Webcast in about 4 hours ...

SpaceX is targeting launch of EchoStar 105/SES-11 from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Center, Florida. The two-hour launch window opens on Wednesday, October 11 at 6:53 p.m. EDT, or 22:53 UTC. A two-hour backup launch window opens on Thursday, October 12 at 6:53 p.m. EDT, or 22:53 UTC. The satellite will be deployed approximately 36 minutes after liftoff. Falcon 9’s first stage for the EchoStar 105/SES-11 mission previously supported SpaceX’s 10th resupply mission to the International Space Station (CRS-10) in February of this year. Following stage separation, Falcon 9’s first stage will attempt a landing on the “Of Course I Still Love You” droneship, which will be stationed in the Atlantic Ocean.

 

Sir Rodney Ffing
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Thank you for the link,

Thank you for the link, AgentB.

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