Author Topic: SpaceX DragonFly Discussion Thread  (Read 273037 times)


Offline Garrett

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Re: SpaceX DragonFly Discussion Thread
« Reply #1 on: 05/21/2014 04:27 PM »
Sweet!

From the document:
Quote
SpaceX's purpose of requesting an experimental permit from the FAA is for SpaceX to test the capability of the DragonFly RLV to execute precision landings on land. SpaceX's need for the experimental permit is to conduct tests to further develop the capability for the Dragon capsule to land, so that it can be reused. One of SpaceX's goals is to reduce the cost of access to space. Being able to resuse Dragon capsule would help meet this goal by eliminating the costs associated with building another capsule
- "Nothing shocks me. I'm a scientist." - Indiana Jones

Offline Lars_J

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Re: SpaceX DragonFly Discussion Thread
« Reply #2 on: 05/21/2014 04:29 PM »
A nice find! Here is what I gleaned from a quick skimming of the PDF (from another thread)


Hmm, interesting information about the "DragonFly RLV" in that PDF:

 - up to four steel landing legs
 - weighs 14000 lbs unfueled
 - maximum proplellant load is 400 gallons

Four kinds of test flights expected:
 - propulsive assist landing (dropped from helicopter with chutes)
 - fully propulsive landing (dropped from helicopter)
 - propulsive assist hop (self launched, parachute deploys)
 - fully propulsive hop (like Grasshopper)

Offline sublimemarsupial

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Re: SpaceX DragonFly Discussion Thread
« Reply #3 on: 05/21/2014 04:29 PM »
Some pretty awesome details in there. They anticipate the program taking two years (2014-2015), and there are four different flight profiles they will be testing.

Offline moralec

Re: SpaceX DragonFly Discussion Thread
« Reply #4 on: 05/21/2014 04:30 PM »
A copy of the table included in the document. Seems the hops will be the most common.

Edit: Great post sublimemarsupial!  ;)
« Last Edit: 05/21/2014 04:31 PM by moralec »

Offline Jarnis

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Re: SpaceX DragonFly Discussion Thread
« Reply #5 on: 05/21/2014 04:33 PM »
Freefall, 5 sec burn at the last moment, soft touchdown.

Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man :)

Offline king1999

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Re: SpaceX DragonFly Discussion Thread
« Reply #6 on: 05/21/2014 04:36 PM »
I am wondering who came up with those cool and apt names like Grasshopper and DragonFly ...  8)

Offline simonbp

Re: SpaceX DragonFly Discussion Thread
« Reply #7 on: 05/21/2014 04:38 PM »
I believe the technical name for that is a brown pants landing...

Offline Jarnis

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Re: SpaceX DragonFly Discussion Thread
« Reply #8 on: 05/21/2014 04:40 PM »
I believe the technical name for that is a brown pants landing...

Capsule might be re-usable, but the pants will be another story...

Offline JBF

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Re: SpaceX DragonFly Discussion Thread
« Reply #9 on: 05/21/2014 04:42 PM »
Freefall, 5 sec burn at the last moment, soft touchdown.

Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man :)

Can anyone model the G-Force curve on that?  It sounds like a rough ride.
"In principle, rocket engines are simple, but that’s the last place rocket engines are ever simple." Jeff Bezos

Offline Lars_J

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Re: SpaceX DragonFly Discussion Thread
« Reply #10 on: 05/21/2014 04:49 PM »
Freefall, 5 sec burn at the last moment, soft touchdown.

Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man :)

Can anyone model the G-Force curve on that?  It sounds like a rough ride.

If anyone can guess the terminal velocity of the capsule, it should be easy to calculate. If the G-load is evenly spread over 5 seconds, it might not be too bad.

Online AncientU

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Re: SpaceX DragonFly Discussion Thread
« Reply #11 on: 05/21/2014 04:50 PM »
Freefall, 5 sec burn at the last moment, soft touchdown.

Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man :)
Slim will do it!

« Last Edit: 05/21/2014 04:53 PM by AncientU »
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Offline A12

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Re: SpaceX DragonFly Discussion Thread
« Reply #12 on: 05/21/2014 04:54 PM »
I believe the technical name for that is a brown pants landing...

Capsule might be re-usable, but the pants will be another story...

Unless they install some kind of space-grade toiled embedded into the seat...

Online corrodedNut

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Re: SpaceX DragonFly Discussion Thread
« Reply #13 on: 05/21/2014 04:54 PM »
Sounds like they will use the Grasshopper pad unless they decide they will need a dedicated pad, which will be a 40' square pad near the SuperDraco facility. The report describes this as the "DragonRider test area".

Offline randomly

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Re: SpaceX DragonFly Discussion Thread
« Reply #14 on: 05/21/2014 04:54 PM »
At 3G's that's dV of 65 mph/sec (sorry for the english units)
seems in the ballpark.

Apollo capsule terminal velocity was roughly 210 miles/hr  at 25,000 ft
« Last Edit: 05/21/2014 04:59 PM by randomly »

Offline meadows.st

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Re: SpaceX DragonFly Discussion Thread
« Reply #15 on: 05/21/2014 04:56 PM »
Thanks to TomNTex for finding the FAA Draft Environmental Assessment:

http://forum.nasaspaceflight.com/index.php?topic=32202.msg1201687#msg1201687

See:

http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20140513_DragonFly_DraftEA(Public).pdf

http://www.faa.gov/about/office_org/headquarters_offices/ast/environmental/review/permits/

My thanks to TomNTex as well but I think my head just exploded! ;)  (I think there is going to have to be a Dragonfly party thread created.)
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Online corrodedNut

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Re: SpaceX DragonFly Discussion Thread
« Reply #16 on: 05/21/2014 04:56 PM »
"The DragonFly RLV is the Dragon capsule with an integrated trunk (which may or may not be attached during a DragonFly operation) and up to four steel landing legs. The Dragon capsule primary structure consists of a welded aluminum pressure vessel, primary heat shield support structure, back shell thermal protection system support structure, and a nosecone. This structure supports secondary structures including eight SuperDraco engines (two in each of the four modules [quadrants]), propellant tanks, pressurant tanks, parachute system, and necessary avionics. The propulsion system includes four self‐contained quadrants with independent sets of propellant tanks for system redundancy. The SuperDraco engine uses a fuel‐centered injector to provide appropriate performance for the application. It is also designed to seal off both fuel and oxidizer from the combustion chamber, enabling operation with fast shut‐off and limited propellant “dribble” volumes.
The DragonFly RLV weighs approximately 14,000 pounds (lbs) un‐fueled, with a height of 17 ft and a base width of 13 ft. Each pair of SuperDraco engines (eight total engines) are mounted to a monolithic aluminum bracket. This bracket is connected to the pressure vessel with three mounts."

Offline Lars_J

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Re: SpaceX DragonFly Discussion Thread
« Reply #17 on: 05/21/2014 04:57 PM »
Sounds like they will use the Grasshopper pad unless they decide they will need a dedicated pad, which will be a 40' square pad near the SuperDraco facility. The report describes this as the "DragonRider test area".

No, the report indicates that it will be a separate pad:
Quote
"The proposed launch pad would be 40 ft by 40 ft located approximately 0.32 mile north of the Grasshopper launch pad."
« Last Edit: 05/21/2014 04:57 PM by Lars_J »

Offline VulcanCafe

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Re: SpaceX DragonFly Discussion Thread
« Reply #18 on: 05/21/2014 04:58 PM »
This might be obvious, but it sure sounds like the DragonFly = Dragon v2 testbed and closely matches the Dragon v2 size. It also seems to echo rumors about the Dragon v2 with the trunk attached, etc.

Please correct me if I'm wrong :)
« Last Edit: 05/21/2014 04:59 PM by VulcanCafe »

Offline Lars_J

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Re: SpaceX DragonFly Discussion Thread
« Reply #19 on: 05/21/2014 04:59 PM »
Yes, it is a Dragon 2 test bed.

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