There's a post game press conference with Elon. He has some neat comments ( around 14m 30s onwards ) about the drone ship ( it's not a barge anymore! ) and the ramping up of launches later this year.
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
Interesting, also some answers about the wind direction for landing, the barge is held stationery, and the rocket arrives leaning into the wind direction.
The barge was 2% pitching - and they thought they could handle two or maybe three times that.
I am quite amazed they can fine tune the rocket thrust to such a degree as to hover.
My read is that the Dragon/ISS encounter/handling is slated for 12:12 UTC on Sunday 17th.
Summary of Elon's comments :
- 50% of future launches ( now on their books ) to above LEO ie. GTO or escape and these will need to be seaborne landings. { BTW for Earth escape is 11.2 km/sec plus }
- the ship with booster will arrive in port this Sunday.
- for such longer throws the lack of remaining propellant @ stage separation prevents boost back to land.
- Elon wished to make clear the distinction b/w space and orbit ie. after stage separation there was 120 tonnes delivered at about 200 km up going 10^4 km/hour laterally. { IMHO a 'kindly indirect aside' to Mr Bezos ? :-) }
- this mission could have come back to land ( with low fuel margin ), but was decided to attempt ship landing with plenty of fuel margin.
- it was like an aircraft carrier landing in that all degrees of freedom ( including the rising and falling vertically ) were exercised.
- both the rocket and the ship were guided toward the same absolute position without mutual communication. The ship had GPS guidance to under one meter tolerance, it has 4 engine pods with 360 degree rotation.
- this booster is likely to re-fly in June, probably to a paying customer, but after full inspection etc including 10 ( ten ) test firings. Ultimate aim is 2 - 3 week turn-around pace.
- their own prior expectation of success for this mission was 2 chances in 3, any failure would have been a new issue as prior failure reasons have been dealt with. The stage was returning into a 50 miles/hour wind.
- a proof of concept of one aspect of the idea of full and rapid re-usability ie. wash it down, fill it up again and off you go !
- ship could have tilted to 8 or 9 % ( sporty ) and still recovered the booster.
- projected launch rate every few weeks by 3rd or 4th quarter this ( calendar ) year.
- put steel shoes on the feet and weld them to the deck ! { great low tech solution BTW :-) }
- when back at port put a grappling fixture at the top, hold it there via a crane, fold the legs up, lay it down onto road transport, take it back to pad 39A etc.
- { there were real dumb questions from one guy } : obviously you put a real payload to earn money while your are testing first stage return, and you shoot out to sea because failure to re-light produces a ballistic missile which could be devastating on impact to land ( some 500 - 1000 km away )
- the next two missions are high throw geostat deliveries so will be "really hot" returns, meant literally as peak heating goes like velocity^3. { I assume this means NO looping boost back and thus high grade drag to an extremely finessed touchdown OR more considerable ship damage ! }
- the third mission from now will be land return.
- Falcon Heavy ( or "Falcon 27" ) will mainly be used for high mass geostationary deliveries.
- long term 1st stage re-use estimates : most components have indefinite lifetime ( say 1000 missions ), the 'hot' components probably 20 to 30 missions but with refurbishment go out to ~ 100 missions.
- Elon hopes that his launch competitors follow SpaceX's lead to re-use ie. $300K fuel costs on a $60M rocket gives a hundred fold decrease in non-fixed costs. { IMHO : in case it is not obvious by now, the competitors will readily go broke otherwise .... }
(A) what is the break even point for launch costs including whatever optimisations apply like recover and refurbish etc, and
(B) when do you achieve A ?
are pretty much answered now .... :-))) }
- suggestion of future nose-cone re-use.
- SpaceX will have succeeded when the things we are excited about now become boring ! :-)))
- late 2017 may see the first crewed launches from SpaceX.
ASIDE : on reflection I would say their craft control algorithms would be a very high value company secret at this point. While much of the visible SpaceX hardware could be copied ( without patent ) but who wants to re-invent the wheel to the tune of several hundred million ? The first 'hot failure' was simply lack of hydraulic fluid in the open circuit for the vane control. There has got to be a ton of those sorts of lessons. Notably Elon chose not to patent most of the visible hardware as it would be just a gift of the blueprints to non-patent-compliant nation states ( read China ).
Cheers, Mike.
( edit ) One 'simple' upgrade idea here is extra grid fins. These don't have to be in the active directional control loop, just provide passive drag ie. either sticking out in the breeze or stay flush. This could really lower that peak heating high up and also increase the fuel margin for active use lower down ....
( edit ) Escape velocity for the Sun from Earth origin is 620+ km/sec ....
( edit ) Another idea. If they are pretty sure in the long term of some general recovery area then attachment of the ship to seafloor anchors via buoys would give a vast improvement in surface/lateral station keeping. This is already mature technology eg. for precision seafloor drilling etc. I'll repeat my prior suggestion of pontooned outriggers to dampen vertical movement and tilt. These measures may not change the limits of position variance but would certainly suppress the rates of change. Meaning that while the booster stage might converge to position beautifully, one crappy wave could rapidly slide the landing zone underneath at the crucial moment. With suitable excess buoyancy the ship could be held downwards in tension against the sea surface .....
... or if you like : have you ever played with an intact rubber duck and felt the upwards force while you hold it down below the level it wants to sit at ? It is amazing how more stable the thing becomes.
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
I am quite amazed they can fine tune the rocket thrust to such a degree as to hover.
This goes back to design decisions made about a decade ago ie. to have high power engines that are also capable of deep throttle. The main trick here is the 'pintle' injector of which ( roughly ) the key component is a conically shaped obstruction to the fuel flow, that can be shifted in position to vary said flow and maintain good mixing/efficiency. The current Merlin 1Ds can each give ~ 800+ kN of thrust ( depending on who is talking ) but right down to 40% of that - below which it would flame out. The Super Draco has a similar deep throttle level. The vacuum Merlin 1D variant has about 9% more thrust.
Cheers, Mike.
( edit ) Now I don't have the blueprints, but my off-the-hip guess at the size of the pintle head ( the conical part ) is about that of your thumb ! To say that this is a highly designed, studied and tested component is an understatement ! :-)
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
I wouldn't have thought that SpaceX is going to be commercially viable until they can repeatedly and reliably recover stages upon land. Nobody is denying that the technical achievement demonstrated of landing upon a moving sea platform was anything other than pretty good engineering. But the logistics of recovering that from that location for re-use does does not compute for me.
We moved on from the early days of capsules on parachutes dumping astronauts in the ocean to the shuttles. I still think that if someone could build a fleet of MkII shuttles, not only could they deliver people and supplies to the ISS, they could launch satellites into orbit. Far more cost effective than SpaceX vehicles.
The shuttles could have been kept going by NASA for another 3-5 years, even though they were only intended to be used for building the ISS, and a bit of supply duty afterwards. But looming planned end of life and lack of spare parts was also an issue, and the political will was to get rid of them, and Congress refused to fund them with any more money, so Nasa didn't have much choice.
Also the Challenger and Columbia disasters have been said by many to be down to NASA management insisting the launches went ahead, when engineers said we aren't ready. M$ syndrome? Russia was happy to offer piggyback ISS trips to the Americans, and meanwhile the Chinese are planning Moonbase 1, while officially the USA are going to the Asteroids (why??) and maybe Mars. Sorry guys, SpaceX may be a very technically clever outfit, and I am impressed, but I wouldn't buy any shares in them. That said I will follow their exploits with interest.
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now
Interesting, also some answers about the wind direction for landing, the barge is held stationery, and the rocket arrives leaning into the wind direction.
The barge was 2% pitching - and they thought they could handle two or maybe three times that.
I am quite amazed they can fine tune the rocket thrust to such a degree as to hover.
If you remember the early videos in this thread from SpaceX's land based test facility the rocket went to a few thousand feet and just hovered there before being brought back to the pad. Those early videos really showed the engine working to maintain position under the rocket.
I am surprised that the goal has always been about "barge" recoveries because of mission parameters. On most launches of this type, including the shuttle, two factors played into launch decisions: 1. best time to launch to achieve rendezvous with intended target and 2. weather conditions at sea level and altitude. Now we need to factor in sea conditions. Do we abort a launch because sea conditions do not favor a positive recovery outcome? Doing so adds to the cost of launch operations. Or do we go and "hope" we can achieve successful capture. To me this adds to the complexity of the go/no go scenario for each mission. At what point does "wet" recovery take 2nd seat to mission objectives
[EDIT] and you sacrifice recovery success?
Maybe Elon Musk will sell so many Tesla electric cars to cover the cost of SpaceX.
He has a huge backlog of orders and this is what kills many startups. Read "The soul of a new machine" by Tracy Kidder which covers this point.
Tullio
I was just looking at the SpaceX Falcon Heavy webpage. With 3 cores its going to require 3 barges (certainly not one "large" barge. The video promo shows all 3 cores returning to a land recovery. Just to watch this thing fly will be interesting enough.
There's a post game press
)
There's a post game press conference with Elon. He has some neat comments ( around 14m 30s onwards ) about the drone ship ( it's not a barge anymore! ) and the ramping up of launches later this year.
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
Interesting, also some
)
Interesting, also some answers about the wind direction for landing, the barge is held stationery, and the rocket arrives leaning into the wind direction.
The barge was 2% pitching - and they thought they could handle two or maybe three times that.
I am quite amazed they can fine tune the rocket thrust to such a degree as to hover.
My read is that the
)
My read is that the Dragon/ISS encounter/handling is slated for 12:12 UTC on Sunday 17th.
Summary of Elon's comments :
- 50% of future launches ( now on their books ) to above LEO ie. GTO or escape and these will need to be seaborne landings. { BTW for Earth escape is 11.2 km/sec plus }
- the ship with booster will arrive in port this Sunday.
- for such longer throws the lack of remaining propellant @ stage separation prevents boost back to land.
- Elon wished to make clear the distinction b/w space and orbit ie. after stage separation there was 120 tonnes delivered at about 200 km up going 10^4 km/hour laterally. { IMHO a 'kindly indirect aside' to Mr Bezos ? :-) }
- this mission could have come back to land ( with low fuel margin ), but was decided to attempt ship landing with plenty of fuel margin.
- it was like an aircraft carrier landing in that all degrees of freedom ( including the rising and falling vertically ) were exercised.
- both the rocket and the ship were guided toward the same absolute position without mutual communication. The ship had GPS guidance to under one meter tolerance, it has 4 engine pods with 360 degree rotation.
- this booster is likely to re-fly in June, probably to a paying customer, but after full inspection etc including 10 ( ten ) test firings. Ultimate aim is 2 - 3 week turn-around pace.
- their own prior expectation of success for this mission was 2 chances in 3, any failure would have been a new issue as prior failure reasons have been dealt with. The stage was returning into a 50 miles/hour wind.
- a proof of concept of one aspect of the idea of full and rapid re-usability ie. wash it down, fill it up again and off you go !
- ship could have tilted to 8 or 9 % ( sporty ) and still recovered the booster.
- projected launch rate every few weeks by 3rd or 4th quarter this ( calendar ) year.
- put steel shoes on the feet and weld them to the deck ! { great low tech solution BTW :-) }
- when back at port put a grappling fixture at the top, hold it there via a crane, fold the legs up, lay it down onto road transport, take it back to pad 39A etc.
- { there were real dumb questions from one guy } : obviously you put a real payload to earn money while your are testing first stage return, and you shoot out to sea because failure to re-light produces a ballistic missile which could be devastating on impact to land ( some 500 - 1000 km away )
- the next two missions are high throw geostat deliveries so will be "really hot" returns, meant literally as peak heating goes like velocity^3. { I assume this means NO looping boost back and thus high grade drag to an extremely finessed touchdown OR more considerable ship damage ! }
- the third mission from now will be land return.
- Falcon Heavy ( or "Falcon 27" ) will mainly be used for high mass geostationary deliveries.
- long term 1st stage re-use estimates : most components have indefinite lifetime ( say 1000 missions ), the 'hot' components probably 20 to 30 missions but with refurbishment go out to ~ 100 missions.
- Elon hopes that his launch competitors follow SpaceX's lead to re-use ie. $300K fuel costs on a $60M rocket gives a hundred fold decrease in non-fixed costs. { IMHO : in case it is not obvious by now, the competitors will readily go broke otherwise .... }
{ So my recent questions :
are pretty much answered now .... :-))) }
- suggestion of future nose-cone re-use.
- SpaceX will have succeeded when the things we are excited about now become boring ! :-)))
- late 2017 may see the first crewed launches from SpaceX.
ASIDE : on reflection I would say their craft control algorithms would be a very high value company secret at this point. While much of the visible SpaceX hardware could be copied ( without patent ) but who wants to re-invent the wheel to the tune of several hundred million ? The first 'hot failure' was simply lack of hydraulic fluid in the open circuit for the vane control. There has got to be a ton of those sorts of lessons. Notably Elon chose not to patent most of the visible hardware as it would be just a gift of the blueprints to non-patent-compliant nation states ( read China ).
Cheers, Mike.
( edit ) One 'simple' upgrade idea here is extra grid fins. These don't have to be in the active directional control loop, just provide passive drag ie. either sticking out in the breeze or stay flush. This could really lower that peak heating high up and also increase the fuel margin for active use lower down ....
( edit ) Escape velocity for the Sun from Earth origin is 620+ km/sec ....
( edit ) Another idea. If they are pretty sure in the long term of some general recovery area then attachment of the ship to seafloor anchors via buoys would give a vast improvement in surface/lateral station keeping. This is already mature technology eg. for precision seafloor drilling etc. I'll repeat my prior suggestion of pontooned outriggers to dampen vertical movement and tilt. These measures may not change the limits of position variance but would certainly suppress the rates of change. Meaning that while the booster stage might converge to position beautifully, one crappy wave could rapidly slide the landing zone underneath at the crucial moment. With suitable excess buoyancy the ship could be held downwards in tension against the sea surface .....
... or if you like : have you ever played with an intact rubber duck and felt the upwards force while you hold it down below the level it wants to sit at ? It is amazing how more stable the thing becomes.
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
RE: I am quite amazed they
)
This goes back to design decisions made about a decade ago ie. to have high power engines that are also capable of deep throttle. The main trick here is the 'pintle' injector of which ( roughly ) the key component is a conically shaped obstruction to the fuel flow, that can be shifted in position to vary said flow and maintain good mixing/efficiency. The current Merlin 1Ds can each give ~ 800+ kN of thrust ( depending on who is talking ) but right down to 40% of that - below which it would flame out. The Super Draco has a similar deep throttle level. The vacuum Merlin 1D variant has about 9% more thrust.
Cheers, Mike.
( edit ) Now I don't have the blueprints, but my off-the-hip guess at the size of the pintle head ( the conical part ) is about that of your thumb ! To say that this is a highly designed, studied and tested component is an understatement ! :-)
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
I wouldn't have thought that
)
I wouldn't have thought that SpaceX is going to be commercially viable until they can repeatedly and reliably recover stages upon land. Nobody is denying that the technical achievement demonstrated of landing upon a moving sea platform was anything other than pretty good engineering. But the logistics of recovering that from that location for re-use does does not compute for me.
We moved on from the early days of capsules on parachutes dumping astronauts in the ocean to the shuttles. I still think that if someone could build a fleet of MkII shuttles, not only could they deliver people and supplies to the ISS, they could launch satellites into orbit. Far more cost effective than SpaceX vehicles.
The shuttles could have been kept going by NASA for another 3-5 years, even though they were only intended to be used for building the ISS, and a bit of supply duty afterwards. But looming planned end of life and lack of spare parts was also an issue, and the political will was to get rid of them, and Congress refused to fund them with any more money, so Nasa didn't have much choice.
Also the Challenger and Columbia disasters have been said by many to be down to NASA management insisting the launches went ahead, when engineers said we aren't ready. M$ syndrome? Russia was happy to offer piggyback ISS trips to the Americans, and meanwhile the Chinese are planning Moonbase 1, while officially the USA are going to the Asteroids (why??) and maybe Mars. Sorry guys, SpaceX may be a very technically clever outfit, and I am impressed, but I wouldn't buy any shares in them. That said I will follow their exploits with interest.
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now
I really like this shot :
)
I really like this shot :
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
RE: Interesting, also some
)
If you remember the early videos in this thread from SpaceX's land based test facility the rocket went to a few thousand feet and just hovered there before being brought back to the pad. Those early videos really showed the engine working to maintain position under the rocket.
I am surprised that the goal has always been about "barge" recoveries because of mission parameters. On most launches of this type, including the shuttle, two factors played into launch decisions: 1. best time to launch to achieve rendezvous with intended target and 2. weather conditions at sea level and altitude. Now we need to factor in sea conditions. Do we abort a launch because sea conditions do not favor a positive recovery outcome? Doing so adds to the cost of launch operations. Or do we go and "hope" we can achieve successful capture. To me this adds to the complexity of the go/no go scenario for each mission. At what point does "wet" recovery take 2nd seat to mission objectives
[EDIT] and you sacrifice recovery success?
Maybe Elon Musk will sell so
)
Maybe Elon Musk will sell so many Tesla electric cars to cover the cost of SpaceX.
He has a huge backlog of orders and this is what kills many startups. Read "The soul of a new machine" by Tracy Kidder which covers this point.
Tullio
SpaceXStats has put the next
)
SpaceXStats has put the next launch as 'Late April' being a geostat insertion for SKY Perfect JSAT.
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
I was just looking at the
)
I was just looking at the SpaceX Falcon Heavy webpage. With 3 cores its going to require 3 barges (certainly not one "large" barge. The video promo shows all 3 cores returning to a land recovery. Just to watch this thing fly will be interesting enough.