SpaceX And/Or Rocketry In General

archae86
archae86
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Elsbeth III is recently

Elsbeth III is recently reported as departing Port Canaveral.  I've not seen confirming information that she has the recovery barge in tow, but as the current indicated date for the AMOS 6 launch is September 3, and the location the Cape, it seems a really good bet.

Mike Hewson
Mike Hewson
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I have it at 5pm Saturday

I have it at 5pm Saturday afternoon my time ( UTC + 10 ) and it's much the same as recent GTO missions ie. about a five tonne throw.

Later next month ( ? 27th as per SpaceX stats site ) is "SpaceX will carry up several of Iridium's next-generation communications satellites on the first flight of seven in a $492 million contract." That'll be from West Coast as polar, and another interesting recovery to study ie. a right angle turn after separation ?

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

archae86
archae86
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Someone on the SpaceX reddit

Someone on the SpaceX reddit has asserted that the AMOS 6 mission is on the heavy side, so more of a challenge to succeed in the recovery landing.  If they are right, presumably this will be a 3-engine landing burn, and riskier than recent successes may have us expecting.

Mike Hewson
Mike Hewson
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archae86 wrote:Someone on the

archae86 wrote:

Someone on the SpaceX reddit has asserted that the AMOS 6 mission is on the heavy side, so more of a challenge to succeed in the recovery landing.  If they are right, presumably this will be a 3-engine landing burn, and riskier than recent successes may have us expecting.

Interesting. I think we'd reasonably be comparing to SES-9 here then, @ 5300kg to GTO with multiple engines used but a euphemistically 'hard' landing ( EHL ). 

Cheers, Mike.

( edit ) Satbeams has Amos-6 at 5500kg, others have it at 5400kg. Hmmm. Either way that's more than SES-9 .... I suppose they'll use the late LOX flushing again. Again I wonder what is the effective performance margin gained for that.

( edit ) OK. The actual satellite manufacturer ( Israel Aerospace Industries ) as of 2012 puts it at 5500kg. That's launch/liftoff mass, the final delivered may be less to orbit ie. loses about 100kg. 

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Mike Hewson
Mike Hewson
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LOL. So a 2015 announcement

LOL. So a 2015 announcement by the manufacturer gives 5.3 ton, which if metric is 5300 kg ( else if US ton is 4808 kg, but the article is quoting metric elsewhere ). I can't find any of the company's press releases this year that refer to AMOS 6.

FWIW : I find this a fascinating question. Energy is everything here. My mass is 93 kg but at altitude ( say SECO )  travelling at 9+ km/sec and so represents ~ 3,766,500,000 = 3.7 GJ. Unfortunately it is non-trivial to quote "how much mass of extra LOX + RP-1 is needed at launch to achieve this". In any event we have been talking ( legitimately ) of a 200 GJ swing in downrange recovery vs. return to land, hence 100kg represents ~ 2 % of that budget. But the sharp question is : are we that close to downrange recovery vs. throwaway ..... and have any optimisations been applied to give a better outcome than SES-9 ?

In the market place, as it were, the far greater sin is going to be failure of payload getting to specified orbit and not whether SpaceX gets to re-use. That is the commercial imperative.

When/if the Heavy gets operational these current GTO payloads will be a doddle, now being quoted/expected at about $90M USD per launch. You could probably punt them to the Moon if you like ( my back-of-the-envelope using 1/R energetics + some mild assumptions ) as you don't have to get to 384,000 km but to 346,000 km where you roll past the neutral point ( ie. where the Moon's gravity is equal to the Earth's ). 

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

archae86
archae86
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Big news: there is now

Big news: there is now actually a scheduled launch meant to employ a used first stage.

I don't think either side has specified how big a discount SES is getting for having SES 10 launch on a "flight proven" rocket sometime in Q4 2016.

I also think that the courage displayed by SES may be partly related to the considerable number of satellites and spares they have (it would not be a terrible set back if they lost one).

In case anyone is keeping score, I seriously doubt space X is anywhere near breaking even on the whole reusable rocket trick now, but they do seem nicely on the way to developing the capability, which should help in the long run.

Anonymous

archae86 wrote:Big news:

archae86 wrote:

Big news: there is now actually a scheduled launch meant to employ a used first stage.

Ah, the final third of this launch, recovery, launch effort.  This should also qualify as a major first step in the recycling effort.  I will be looking forward to this launch too.  I wish for success but should that not be the case it is not the end of re-cycling.  Just another opportunity to figure out what went wrong.  To try again.  And to succeed.  Remember barge landings were not quite the walk in the sunshine that the early prototypes enjoyed on land recovery efforts.  

Mike Hewson
Mike Hewson
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Go Quest has just left

Go Quest has just left Canaveral.

First re-use ? Wooo ... woooo ..... wooo :-0

SES-10 is listed as sub synchronous ie. orbiting lower than GTO and hence faster ( period less than a sidereal day ). On the face of it that requires less payload energy than GTO to get there .... so more for booster recovery ?

I guess we may learn exactly what 're-use' means here ie. all original nine engines etc ? We could expect a scrub down, repaint and tank re-fills. What else may have needed replacing or refurbishing ( legs ? vanes ? ashtray ? ) yada yada .... 

Cheers, Mike.

( edit ) SpaceX has setup a YouTube feed for the expected time.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Anonymous

 We are having some very bad

 We are having some very bad weather here and it is predicted to last through Monday, 9/5.  Lots of rain and low ceiling.  Occasional wind guts will probably exceed launch parameters.  But you never know.  I would believe that clear visual tracking would be a requirement.  

Mike Hewson
Mike Hewson
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Ah. Here is the technical

Ah. Here is the technical webcast link. I think the launch time has been pushed back three hours though.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

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