Author Topic: CNES youtube video on SpaceX's reusability effort  (Read 15475 times)

Offline Nilof

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The video is in French. I'll get around to making a translated transcript in a little while. But the quality like for all CNES videos is very good and gets into some of the technical aspects, the CNES channel is my personal favorite among the youtube channels of governmental space agencies.

Essentially it is a news clip that describes the SpaceX reusability effort thoroughly and with lots of praise, although with some defensive comments about the economics of reusability and on how looking into reusable rocket options has been the day job of many CNES employees for decades. ;)

Definitely worth watching if you can understand the French.
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline lele

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #1 on: 02/10/2015 12:40 PM »
That was quite interesting, thanks.

Online Bynaus

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #2 on: 02/10/2015 01:21 PM »
The most remarkable thing they say in that video, IMHO, is that CNES has made its own (independent) estimate of the mass to geostationary transfer orbit for both F9R and FHR, which they calculate to be "close to 2 tons" and "6-7 tons", respectively. It is unclear however whether that includes re-use of the upper stage as well, as they keep stressing that they are talking of the "final" version of the reusable rocket.

Online Chris Bergin

Re: CNES youtube video on SpaceX's reusability effort
« Reply #3 on: 02/10/2015 01:23 PM »
Yeah, I'd really love a transcript of the quotes in this!

Offline Robotbeat

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #4 on: 02/10/2015 01:27 PM »
At some point, it's cheaper to just build an RLV than to pay people to study it some more.

I hope CNES (or whoever in Europe) builds an RLV.
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Offline nadreck

Re: CNES youtube video on SpaceX's reusability effort
« Reply #5 on: 02/10/2015 01:29 PM »
At some point, it's cheaper to just build an RLV than to pay people to study it some more.

I hope CNES (or whoever in Europe) builds an RLV.

Yes but you could say that about so many space projects.
It is all well and good to quote those things that made it past your confirmation bias that other people wrote, but this is a discussion board damnit! Let us know what you think! And why!

Online wannamoonbase

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #6 on: 02/10/2015 02:16 PM »
At some point, it's cheaper to just build an RLV than to pay people to study it some more.

I don't know, I'd have to see on study on that hypothesis first.
SpaceX, just a few things planned for 2018: FH, Starlink Prototypes, Block 5, Dragon 2, Increased launch rate.

Offline kevinof

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #7 on: 02/10/2015 02:28 PM »
true but at least with the likes of SpaceX they have put away the study books and powerpoints and are giving it a go. It might not work, might not be financially feasible but at least they will find out. They will (eventually) get a first stage back and be able to pull it apart and see if re-use makes sense. That's far more than ANY study has ever done.


At some point, it's cheaper to just build an RLV than to pay people to study it some more.

I hope CNES (or whoever in Europe) builds an RLV.

Yes but you could say that about so many space projects.

Offline BusterSky

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #8 on: 02/10/2015 02:47 PM »
true but at least with the likes of SpaceX they have put away the study books and powerpoints and are giving it a go. It might not work, might not be financially feasible but at least they will find out. They will (eventually) get a first stage back and be able to pull it apart and see if re-use makes sense. That's far more than ANY study has ever done.


At some point, it's cheaper to just build an RLV than to pay people to study it some more.

I hope CNES (or whoever in Europe) builds an RLV.

Yes but you could say that about so many space projects.

Yes, the just-do-it attitude is precisely why Space X is getting ahead of ESA. I remember reading a paper where ESA's head of administration said they could not have developped the Falcon 9 and Grasshopper as quickly as Space X due to 1) an approach that always tends to favor powerpoints, endless plans and overly complicated solutions  2) redtape and government strings.  Ariane 6 could be doomed as a result of this inefficiency.

« Last Edit: 02/10/2015 02:52 PM by BusterSky »

Offline Cinder

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #9 on: 02/10/2015 02:50 PM »
I can translate it later today if someone else hasn't gotten it done yet.
The pork must flow.

Offline SwissCheese

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #10 on: 02/10/2015 03:22 PM »
So here you have a translation of the transcript (French version below):


The reusable rocket: SpaceX challenge

These images were taken January 10, 2015, somewhere in the Atlantic Ocean. A rocket part crashes into an unmanned floating platform. It is a recovery test of the first stage of the Falcon 9 rocket, by the US company that produces it, SpaceX. This company, established in 2002, is one of the main NASA contractors.

Christophe Bonnal - senior expert in the management of launch vehicles - CNES

C.B.: SpaceX has a very progressive mentality: they test, they test, they test ... They first started from a very small launch vehicle called Falcon 1, then Falcon 1e, then larger : Falcon 9, then a bigger version of Falcon 9. Then they wondered: and if we tried to reuse the first stage, which is a big stage, with 9 engines and which is rather complex and expensive.

After a series of tests like this one, which consists of raising small rockets up to 1 km altitude and then landing them vertically, SpaceX company decided to attempt the recovery of the first stage of its Falcon 9 rocket in actual conditions. On January 10, the launch vehicle carrying a resupply capsule to the International Space Station lifted off from Florida. Three minutes after launch, as expected, the first stage of the launch vehicle came off; the resupply capsule continued on its way, carried away by the second stage of the rocket; it later arrived safely at destination. Once separated from the rest of the rocket, the first stage restarted its engines and began a series of delicate maneuvers to land on that barge, located offshore the launch pad. Things did not entirely happen as expected, but the images taken by a camera on board the barge still show that the first stage arrived at the desired location.

C.B.: This is extremely impressive. It is very accurate. The fact that they arrived on the barge is already absolutely remarkable. It shows a very good mastery of all the braking operation, aiming, piloting.

It was very close for SpaceX to win its bet. But what is the reason for this failure?

C.B.: At the top of the stage, they have 4 sorts of aerodynamic control surfaces that are there to control somehow the global attitude of the stage, and unfortunately the hydraulic cylinders ran out of oil just before landing, too bad.

Adapting a launch vehicle to make it reusable is not without consequence on the mass of the satellite it will be able to place in orbit.

C.B.: You can have the same launch vehicle in 2 versions, the non-reusable Falcon 9, for example. It is able to put about 3.7 tonnes - 3.8 tonnes into geostationary transfer orbit. Now if the same version is equipped with the feet and all the fuel required for the return, etc. This same launch vehicle but in a reusable version is only capable of half of the performance of the expendable launch vehicle.

According to the calculations of CNES engineers, the Falcon 9 launch vehicle in its reusable version could put satellites weighing around 2 tons into geostationary orbit, a performance that is not adapted to the demand on the satellite launch market. But SpaceX does not intend to stop there. They project a heavier version of their launch vehicle.

C.B.: This is SpaceX Falcon 9 Heavy project, which has 3 times the same stage, and this provides a much higher performance. According to the calculations made at CNES, we believe that the final performance of this reusable Heavy version would be on the order of 6 or 7 tons into geostationary transfer orbit. That is the heart of the market.

If SpaceX is able to develop its reusable launch vehicle, it remains to be shown that it is more cost effective than a conventional expendable launch vehicle.

C.B.: It is obvious that if we reuse the engines of the stage, these stages, these engines, we do not have to repay them. But first they are in poorer condition, so the probability of success of the next mission is probably lower. We also produce fewer stages, and if we produce fewer, they become more expensive.

If the idea of a reusable rocket is bold, it is not new. Other spatial domain actors like CNES have long been thinking about it.

C.B.: At CNES, with all our experience in the launch vehicles, we have been working on reuse for 30 years, with tracks that are not promising, so we cut, and others which are investigated again, and others, so I'd say the work on reuse that we are carrying out currently is completely independent of the Falcon initiative. It really is our normal, daily job. We work on small launch vehicles, we work on the very large (launch vehicles), on reusable (launch vehicles), etc., in order to know what is promising. We live in a great time.


And the French transcript:

La fusée réutilisable : le pari de SpaceX

Ces images ont été prises le 10 janvier 2015, quelque part dans l’océan atlantique. Un morceau de fusée vient percuter une plate-forme flottante déserte. Il s’agit d’un essai de récupération du premier étage de la fusée Falcon 9, par la société américaine qui la produit, SpaceX. Cette société créée en 2002 est l’un des principaux prestataires de la NASA.

Christophe Bonnal – Expert senior à la direction des lanceurs - CNES

C.B. : SpaceX a une mentalité très progressive : ils testent, ils testent, ils testent… Ils sont parti d’abord d’un tout petit lanceur qui s’appelait Falcon 1, Falcon 1e, puis plus gros : Falcon 9, une version plus grosse de Falcon 9, ils se sont dit tiens, et si on essayait de réutiliser le premier étage, qu’est un gros étage, avec 9 moteurs et qui est quand même complexe et cher.

Après une série de tests comme celui-ci, consistant à élever des petites fusées jusqu’à 1 km d’altitude pour ensuite les faire atterrir verticalement, la société SpaceX a décidé de tenter la récupération du premier étage de sa fusée Falcon 9 en conditions réelles. Le 10 janvier dernier, le lanceur transportant une capsule de ravitaillement pour la station spatiale internationale s’est arraché du sol de la Floride. Trois minutes après le lancement, comme prévu, le premier étage du lanceur s’est détaché, la capsule de ravitaillement a poursuivi sa course, emportée par le deuxième étage de la fusée ; elle arrivera sans encombre à destination. Une fois séparé du reste de la fusée, le premier étage a rallumé ses moteurs et entamé une série de manœuvres délicates pour aller se poser sur cette barge, située au large du pas de tir. Les choses ne se sont pas tout-à-fait passées comme prévu, mais les images prises par une caméra à bord de la barge montrent tout de même que le premier étage est arrivé à l’endroit voulu.

C.B. : C’est extrêmement impressionnant. C’est très précis. Le fait d’être arrivé sur la barge, déjà c’est absolument remarquable. Ca démontre une très bonne maîtrise de toute l’opération de freinage, visée, pilotage.

Il s’en est fallu de peu pour que SpaceX remporte son pari. Mais quelle est la raison de cet échec ?

C.B. : Tout au sommet de l’étage, ils ont 4 espèces de gouvernes aérodynamiques qui sont là justement pour finalement contrôler un peu l’attitude globale de l’étage, et malheureusement ces vérins hydrauliques sont tombés en panne d’huile juste avant l’atterrissage, dommage.

Adapter un lanceur pour le rendre réutilisable n’est pas sans conséquence sur la masse du satellite qu’il va pouvoir placer en orbite.

C.B. : Vous pouvez avoir un même lanceur en 2 versions, donc Falcon 9 non réutilisable, par exemple. Lui il fait environ 3.7 tonnes – 3.8 tonnes en orbite de transfert géostationnaire. Maintenant si cette même version est équipée des pieds et avec tout le carburant nécessaire pour le retour, etc. Ce même lanceur mais en version réutilisable n’est capable de faire que la moitié de la performance du lanceur consommable.

Selon les calculs des ingénieurs du CNES, le lanceur Falcon 9 dans sa version réutilisable pourrait mettre en orbite géostationnaire des satellites pesant aux alentours de 2 tonnes, une performance qui ne serait pas adaptée à la demande sur le marché du lancement des satellites. Mais SpaceX ne compte pas s’arrêter là. Ils ont en projet une version plus lourde de leur lanceur.

C.B. : C’est le projet du Falcon 9 Heavy de SpaceX, où typiquement donc ils ont 3 fois le même étage, et ça ça permet d’avoir une performance beaucoup plus élevée. D’après les calculs qu’on a menés au CNES, on pense que la performance finale de cette version Heavy réutilisable serait de l’ordre de 6 ou 7 tonnes en orbite de transfert géostationnaire. Là, c’est le cœur du marché.

Si SpaceX parvient à mettre au point son lanceur réutilisable, il restera à démontrer qu’il est plus rentable qu’un lanceur consommable classique.

C.B. : C’est évident que si on va se resservir des moteurs de l’étage, ces étages, ces moteurs, on n’a pas à les repayer. Mais déjà ils sont en moins bon état, donc la probabilité de succès de la mission suivante est sans doute plus faible. Du coup on en produit moins des étages, et si on en produit moins, ils deviennent plus chers.

Si l’idée de la fusée réutilisable est audacieuse, elle n’est pas neuve. D’autres acteurs du spatial comme le CNES y réfléchissent depuis longtemps.

C.B. : Le CNES, avec toute son expérience dans les lanceurs, ça fait 30 ans qu’on travaille sur la réutilisation, avec des voies qui ne sont pas prometteuses, et donc on coupe, et d’autres qu’on reprend, et autres, donc j’aurais tendance à dire le travail sur la réutilisation que nous menons aujourd’hui est complètement indépendant de l’initiative Falcon. C’est vraiment notre boulot quotidien, normal, on travaille sur les petits lanceurs, on travaille sur les très gros, on travaille sur le réutilisable, etc, de manière à savoir qu’est-ce qui est prometteur. On vit une époque formidable.
« Last Edit: 02/12/2015 08:08 AM by SwissCheese »

Offline kevinof

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #11 on: 02/10/2015 03:25 PM »
Thanks Swisscheese. My French is rusty so much appreciated.

Online Elmar Moelzer

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #12 on: 02/10/2015 06:13 PM »
I guess when they say geostationary orbit, they mean GSO, not GTO, or otherwise, their numbers are way below what SpaceX provides on their website (4,850kg, which already includes first stage reuse).

Offline gosnold

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #13 on: 02/10/2015 07:00 PM »
I guess when they say geostationary orbit, they mean GSO, not GTO, or otherwise, their numbers are way below what SpaceX provides on their website (4,850kg, which already includes first stage reuse).
Could it be a 0° inclination standard delta-v deficit (1500m/s?) GTO?

Online abaddon

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #14 on: 02/10/2015 10:07 PM »
I guess when they say geostationary orbit, they mean GSO, not GTO, or otherwise, their numbers are way below what SpaceX provides on their website (4,850kg, which already includes first stage reuse).

I believe their numbers include first stage engine-out margin, not first stage recovery.

Online Semmel

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #15 on: 02/11/2015 07:39 AM »
CNES is sort of a cultural competitor to SpaceX. I dont think they are outright lying about the numbers but I find it quite reasonable for them to be conservative with their calculations. Unless we understand how they arrived at their numbers, we have little chance of finding out what the cause of the discrepancy is. I dont think speculation helps either.

Offline SwissCheese

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #16 on: 02/11/2015 09:20 AM »
I guess when they say geostationary orbit, they mean GSO, not GTO, or otherwise, their numbers are way below what SpaceX provides on their website (4,850kg, which already includes first stage reuse).

He specified "orbite de transfert géostationnaire", i.e. GTO, not GSO.

Could it be a 0° inclination standard delta-v deficit (1500m/s?) GTO?

It's the most plausible explanation. And the other numbers for reusable versions must be with RTLS.

The other explanation is either SpaceX is not telling their true numbers or CNES does not want to see (or tell publicly) the reality...
« Last Edit: 02/11/2015 09:24 AM by SwissCheese »

Offline Jarnis

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #17 on: 02/11/2015 09:59 AM »
Their numbers probably won't take into account upcoming uprating of the Merlin engine (from "85% to 100%" whatever that will mean in practice), plus propellant densification.

No idea if the SpaceX website numbers take those upgrades into account. Since they are currently selling rides for several years in the future, I'd make a guess of "yes".

Online Elmar Moelzer

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #18 on: 02/11/2015 03:51 PM »
I guess when they say geostationary orbit, they mean GSO, not GTO, or otherwise, their numbers are way below what SpaceX provides on their website (4,850kg, which already includes first stage reuse).

I believe their numbers include first stage engine-out margin, not first stage recovery.
That's not what Shotwell said.

Offline guckyfan

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #19 on: 02/11/2015 04:23 PM »
Spare capacity for both engine out and RTLS does not make much sense. They reserve the fuel for RTLS. In the rare case of engine out they deliver the payload but may lose the stage if it happens early. Seems a very good trade. Merlin 1D did not have a single engine failure yet.


Online Chris Bergin

Re: CNES youtube video on SpaceX's reusability effort
« Reply #20 on: 02/11/2015 04:25 PM »
Many thanks SwissCheese! :)

Offline S.Paulissen

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #21 on: 02/11/2015 05:09 PM »
I guess when they say geostationary orbit, they mean GSO, not GTO, or otherwise, their numbers are way below what SpaceX provides on their website (4,850kg, which already includes first stage reuse).

There was a version of the website that explicitly said the 4.850kg was to a GTO -1800m/s orbit.  I also recall an interview where Shotwell Elon said that F9 payload to -1500m/s SSO is used in order to compete on level footing with competitors such as Arianespace and that payload to this orbit was only about 3,500kg. 

HAH!  My addled-brain served me well.  Source:
http://aviationweek.com/blog/falcon-9-performance-mid-size-geo

EDIT: Someone else quoting the old website version I mentioned, source:
http://forum.nasaspaceflight.com/index.php?topic=35533.65;wap2
« Last Edit: 02/11/2015 05:12 PM by Exclavion »
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Offline baldusi

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #22 on: 02/12/2015 04:20 PM »
Ok, this is the first subtitle that I actually do, and rather than knowing French I rather had to follow it phonetically. But here it is the French SRT subtitle. I did the English one, from the French base. I did downloaded the video file, but I'm not sure I can upload it. Besides the fact that it is 100MB, I'm not sure about the copyright situation. But if you are in a country where you can download it, any reasonable player should be able to play the subtitles.
« Last Edit: 02/12/2015 04:52 PM by baldusi »

Offline cheesybagel

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #23 on: 03/03/2015 09:46 PM »
Nice video. Thanks for the link. It is good to see that CNES is not dismissive about this effort. But I think they are still underestimating SpaceX a lot.

Offline fatjohn1408

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #24 on: 03/03/2015 11:40 PM »
I guess when they say geostationary orbit, they mean GSO, not GTO, or otherwise, their numbers are way below what SpaceX provides on their website (4,850kg, which already includes first stage reuse).
Could it be a 0° inclination standard delta-v deficit (1500m/s?) GTO?
This. 4.85 tonnes don't include first stage reuse. Why? Because the engines do not run on fairy dust.

Offline Lars-J

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #25 on: 03/03/2015 11:53 PM »
I guess when they say geostationary orbit, they mean GSO, not GTO, or otherwise, their numbers are way below what SpaceX provides on their website (4,850kg, which already includes first stage reuse).
Could it be a 0° inclination standard delta-v deficit (1500m/s?) GTO?
This. 4.85 tonnes don't include first stage reuse. Why? Because the engines do not run on fairy dust.

Does the upcoming 15% thrust upgrade, propellant densification, and upper stage stretch fall under the "fairy dust" category? :)

Offline llanitedave

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #26 on: 03/04/2015 03:06 AM »
If so, I'd hate to have some of that fairy dust falling on MY head!
"I've just abducted an alien -- now what?"

Offline Kabloona

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #27 on: 03/04/2015 08:09 PM »
There was a version of the website that explicitly said the 4.850kg was to a GTO -1800m/s orbit.  I also recall an interview where Shotwell Elon said that F9 payload to -1500m/s SSO is used in order to compete on level footing with competitors such as Arianespace and that payload to this orbit was only about 3,500kg. 

And just for comparison, the most recent ABS/Eutelsat mission was about 4,150 kg to GTO -1600 m/s:

http://forum.nasaspaceflight.com/index.php?topic=36065.msg1340922#msg1340922
« Last Edit: 03/04/2015 08:11 PM by Kabloona »

Online AncientU

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #28 on: 03/05/2015 12:32 PM »
Nice video. Thanks for the link. It is good to see that CNES is not dismissive about this effort. But I think they are still underestimating SpaceX a lot.

They and many others have been underestimating SpaceX.  The comments about the delicate and complex maneuvers to get stage back to the ASDS do show recognition of the technical difficulty of that achievemen, so attitude might be changing.

CNES has worked the reusability problem for 30 years(!!!) and have zip to show for it.  ULA has 'determined' it isn't economically feasible -- studies that are parroted here frequently. 

Studies show many things are impossible until someone does them.

IMO, we have a case of not invented here... Works fine until the product starts taking market share.
« Last Edit: 03/05/2015 09:43 PM by AncientU »
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Offline floss

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #29 on: 03/07/2015 06:05 PM »
Nice video. Thanks for the link. It is good to see that CNES is not dismissive about this effort. But I think they are still underestimating SpaceX a lot.

They and many others have been underestimating SpaceX.  The comments about the delicate and complex maneuvers to get stage back to the ASDS do show recognition of the technical difficulty of that achievemen, so attitude might be changing.

CNES has worked the reusability problem for 30 years(!!!) and have zip to show for it.  ULA has 'determined' it isn't economically feasible -- studies that are parroted here frequently. 

Studies show many things are impossible until someone does them.

IMO, we have a case of not invented here... Works fine until the product starts taking market share.


True but whose market ?

Offline Robotbeat

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #30 on: 03/07/2015 06:20 PM »
Nice video. Thanks for the link. It is good to see that CNES is not dismissive about this effort. But I think they are still underestimating SpaceX a lot.

They and many others have been underestimating SpaceX.  The comments about the delicate and complex maneuvers to get stage back to the ASDS do show recognition of the technical difficulty of that achievemen, so attitude might be changing.

CNES has worked the reusability problem for 30 years(!!!) and have zip to show for it.  ULA has 'determined' it isn't economically feasible -- studies that are parroted here frequently. 

Studies show many things are impossible until someone does them.

IMO, we have a case of not invented here... Works fine until the product starts taking market share.


True but whose market ?
In the case of a reusable Falcon Heavy cheaper than an expendable Falcon 9, ALL of ArianeSpace's launch market that isn't captive (i.e. govt launches).
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline floss

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #31 on: 03/07/2015 07:34 PM »
Brilliant that increases assurance that a satellite will be launched if one launcher fails .

Offline friendly3

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #32 on: 03/07/2015 08:22 PM »
Brilliant that increases assurance that a satellite will be launched if one launcher fails .

Is that a joke?

Offline floss

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Re: CNES youtube video on SpaceX's reusability effort
« Reply #33 on: 03/07/2015 08:39 PM »
Brilliant that increases assurance that a satellite will be launched if one launcher fails .

Is that a joke?


No after all the failures that have happened in the launcher industry at least two reliable  launchers are needed to avoid costly delays in a satellites lifetime .


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