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Forum:Commercial Space - Military Space
Topic:[Discuss] SpaceX Falcon 9 v1.1/CASSIOPE launch
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GACspaceguyI am sure they have to work out range safety issues and contingency sites, as well as weather constraints.

My question I ponder is how much return fuel each stage would need to carry and how does that impact the economics of its reusability.

gliderpilotukSame (unanswered) question I posed about Grasshopper. It's not just the extra fuel for landing, but the extra launch fuel required to launch the extra landing fuel! It's a great concept but on the face of it one where risk (versus a parachute or runway landing) and cost efficiency seem sacrificed for convenience (of landing location). Will they carry a backup parachute system?

It would also be interesting to see the costs of vehicle refurb versus new build.

Robert PearlmanElon Musk and the engineers at SpaceX are intelligent individuals. I doubt they would undertake such a venture if they didn't feel it would result in reduced costs and increased efficiency.

They are a commercial company however, so I don't expect them to lay out all the particulars so their competition can follow suit.

Originally posted by Robert Pearlman:
Elon Musk and the engineers at SpaceX are intelligent individuals.
Absolutely agree, I would just love to see the data on how the system works and how it pays back. It has never been done before and the details of how it will work out are interesting me.

Agree with the proprietary nature of the details though, as I deal with those rules everyday myself.

Robert PearlmanI think more details will be shared as SpaceX moves closer to a first stage land recovery.

I would certainly expect the media to press for more details, especially if the system is put into place for NASA-sponsored flights.

Robert PearlmanSpace News spoke with Elon Musk about the upcoming flight.
Privately owned SpaceX planned to conduct a static-test firing of the rocket's new Merlin 1D engines the weekend of Sept. 7-8, the last major hurdle before a launch attempt could be made as early as a week or two later, founder and chief executive Elon Musk told SpaceNews. At press time, a NASA manifest had the launch slated for Sept. 14.

"We're being, as usual, extremely paranoid about the launch and trying to do everything we possibly can to improve the probability of success, but this is a new version of Falcon 9," Musk said.

With regards to the "soft" water landing...
"Just before we hit the ocean, we're going to relight the engine and see if we can mitigate the landing velocity to the point where the stage could potentially be recovered, but I give this maybe a 10 percent chance of success," Musk said.

In a related program called Grasshopper, SpaceX has been developing a booster stage that can fly itself back to a launch pad.

"We've never attempted to land Grasshopper on water. We don't know if the radar system will detect the water surface level accurately. We don't know all sorts of things, so I really give it a very tiny chance of success. But we're going to see what data we can learn," Musk said.

Robert PearlmanPer SpaceX:
September 29th, the upgraded Falcon 9 rocket will launch a demonstration mission from Vandenberg Air Force Base. The launch window opens at 9:00 a.m. PDT. The launch will be webcast beginning at approximately 8:15 a.m. PDT at
A press kit for the flight can be found here.
Joel KatzowitzI was at SpaceX headquarters in Hawthorne CA on Thursday for a meeting. The buzz throughout the building in anticipation of today's launch was amazing. Everyone who works there feels it's their vehicle, their mission.

What an exciting and inspiring place to visit.

Robert PearlmanThough the recovery of the first stage did not go as planned, they were able to recover several parts.
"I heard that they were able to recover the interstage and a number of components from the engine bay and some of the composite overwrapped pressure vessels," [SpaceX founder and CEO Elon] Musk told reporters in a telecon following the flight. "That's all I know at this point, there may be more."
I have inquired with SpaceX what the intentions are with those parts, whether they may be reused (if in serviceable shape) or will be kept as engineering or display units.
Jim Behling
Originally posted by Joel Katzowitz:
What an exciting and inspiring place to visit.
No different than other companies that fly space hardware.

Robert Pearlman
Originally posted by GACspaceguy:
I am sure they have to work out range safety issues and contingency sites, as well as weather constraints.
Elon Musk briefly addressed range safety during a post-launch media telecon on Sunday (Sept. 29) afternoon.

He said that SpaceX has been working with the Eastern Range and that they have chosen a remote site at Cape Canaveral (Musk didn't want to disclose the site yet).

SpaceX's next attempt at recovering the first stage will be on their third commercial resupply launch to the space station, currently slated for February.

I ponder is how much return fuel each stage would need to carry and how does that impact the economics of its reusability.
Musk said for a water landing payload capability is reduced by 15 percent; by 30 percent for a land touchdown.
GACspaceguyThanks for the info update Robert. The concept is great and the fuel tradeoff is less than I thought it may be for the land touchdown.

GlintSpaceX seems to be vigorously denying an explosion of the Falcoln 9 second stage following separation of its multiple payloads. This is being reported in a number of places, including Aviation Week.

Seems that radar data reviewed by revealed an unually large debris field along the orbital path leading to speculation that the second stage had unexpectedly disintegrated or even exploded.

SpaceX denies any explosion occurred and is blaming it on a scenario in which "possible insulation came off."

Here's a pseudo random link, from Business Insider (of all places), that provides statements from both sides.

Robert PearlmanHere is SpaceX's statement, in its entirety:
Following separation of the satellites to their correct orbit, the Falcon 9 second stage underwent a controlled venting of propellants (fuel and pressure were released from the tank) and the stage was successfully safed. During this process, it is possible insulation came off the fuel dome on the second stage and is the source of what some observers incorrectly interpreted as a rupture in the second stage. This material would be in several pieces and be reflective in the Space Track radar. It is also possible the debris came from the student satellite separation mechanisms onboard.

SpaceX will continue to review to help identify the source of the extra debris, but our data confirms there was no rupture of any kind on the second stage.

GlintSpaceX has made multiple statements regarding the debris field in the vicinity of the orbital track. In a couple of them Elon Musk comes off as appearing guilty of invoking the shooting the messenger fallacy:
  • Concerning the story being posted on the international Russian space blog Zarya, "The Russians are our main competitors, so I would take what they say with a grain of salt."

  • Belittling the observations from "...we do know it's common that the first measurements from Space-Track are not very accurate and sometimes mixed up ... usually takes a few days for them to sort it all out..."
Even if these views have some validity, it's unbecoming.
Robert PearlmanMusk was forthcoming on the post-launch media telecon, openly admitting to what went wrong on the flight and in some detail. I don't see any reason he would switch tactics and lie about the second stage, when he had already disclosed the planned second burn was aborted.
GlintI'm not convinced that Musk has been all that forthcoming. His statment that "the Falcon 9 second stage underwent a controlled venting of propellants (fuel and pressure were released from the tank) and the stage was successfully safed" has overlooked the fact that this safing activity may have been necessary as a result of the failure of a mission objective.

Following release of the payloads, the second stage was supposed to be reignited, but failed. So it wasn't really as routine as Musk tries to make it sound by glossing over this anomaly. The restartable engine is supposed to be a selling feature for the Falcoln 9.

In this article, "SES is awaiting a detailed explanation from SpaceX as to why the second stage of its upgraded Falcon 9 booster failed to reignite during a flight on Sunday."

Looks like SpaceX has some explaining to do whether or not the second stage exploded.

Robert PearlmanMusk said hours after the launch that his engineers believed they knew the cause of the second stage's failure to re-light and knew how to correct for it.

It would be a matter of course that SpaceX would brief SES before their launch. There is nothing unusual with SES requesting a technical description of what went wrong, nor does it in any way suggest Musk has anything to hide.

Robert PearlmanFrom SpaceX's mission summary released today (see the update topic for the full statement):
Following separation of the last payload, SpaceX attempted an internal milestone of relighting the second stage. Conditions appeared satisfactory for relight of the upper stage engine as the stage flew over Antarctica. The engine initiated ignition, with pressure rising in the thrust chamber to about 400 psi, but the flight computer sensed conditions did not meet criteria and it aborted the ignition. SpaceX believes it understands the issue which didn’t involve anything fundamental, rather a need to iron out some of the differences between operating the engine on the ground versus in a vacuum. SpaceX has actually relit the Merlin engine in ground testing a dozen times in some cases and SpaceX is confident it can make the necessary adjustments before the next flight.

Despite reports to the contrary, the Falcon 9 second stage remained intact and healthy following spacecraft separation. It takes a few days to get the data from the Air Force Satellite Control Network into the SpaceX data system for review, but the data confirms the stage passed over Hawaii from approximately 1748 to 1754 Universal Time (10:48-10:54 PDT), roughly 1 hr 48 minutes after launch, starting into our second orbit. SpaceX still had power on the second stage, and the transmitters were left on to drain the batteries (standard procedure).

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