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SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,433

Re: Space X launch

not just heat shield by the looks of the capsule in post #43 need to be reviewed before using again....

GW Johnson

Member

From: McGregor, Texas USA

Registered: 2011-12-04

Posts: 5,801

Website

Re: Space X launch

Don't be fooled by burn scars. 

The Dragon has PICA-X panels for its blunt surface heat shield.  That's a carbon / phenolic ablative material much lighter than the old reinforced composite phenolics of long ago.  Some sort of impregnated honeycomb structure,  or similar.  The porosity gives it much lower density. 

The metal outer hull sides are covered with an ablative paint.  It has a name like "SPAM" or something like it.  "Spacex Proprietary Ablative Material",  or some such name.  Those ugly burn scars notwithstanding,  you just do a wipe-down and repaint it. 

GW

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GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,433

Re: Space X launch

SPAM...interesting acronym... here is what I found on what has been discribed as the means to making a product for reuse.

https://ntrs.nasa.gov/archive/nasa/casi … 002341.pdf
https://www.nasa.gov/sites/default/file … m-List.pdf

https://www.spaceflightnow.com/falcon9/005/dragon.html

http://innerspace.net/uncategorized/hig … sentation/

Dragon V2:  The crew carrying  Dragon which was formally unveiled in May, is indeed comprised of operational components, and not a display as some had suggested. The primary structure is currently undergoing structural tests as part of the Dragon Primary Structural Qualification, which is milestone #14 under CCiCap.

The outer shell will be included on the pad abort test vehicle.  As for that shell, the black areas, as most people are aware, are the PICA-X heat resistant tiles currently making up the heat shield of the cargo Dragon. The white components are another homegrown product; SPAM, or SpaceX Proprietary Ablative Material.

Any Dragon V2 under NASA contract will a new vehicle, and will descend by parachute to dry land, with a brief deceleration burn immediately before touchdown. Shock attenuating legs will provide the final cushion. Targeted landing for abort are off Halifax Nova Scotia, and Shannon, Ireland.

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,433

Re: Space X launch

One of the things Nasa has been striving for is common launcher capability such that payloads can ride on any vehicle.
Successful Static Fire Test Sets SpaceX on Target for Post Labor Day Launch of USAF X-37B Mini-Shuttle Sept. 7

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,433

Re: Space X launch

SpaceX will test its Crew Dragon capsule next week, following explosion in April

will conduct a “static fire” test on the capsule next week. The test will ensure that when the capsule’s emergency engines fire, everything operates as planned. To perform the test, the capsule will be strapped to the ground while it fires its SuperDraco emergency engines.

The high-thrust SuperDraco engines use what is called hypergolic propellant, which has two components that spontaneously ignite when they come into contact. These engines form part of the launch abort system, an important part of any manned capsule, which provides a way for the crew to separate from the capsule in the event of an emergency during launch.

The valve allowed propellant to leak into the high-pressure helium tubes, and the presence of fuel in a high-pressure system is what led to the explosion. SpaceX announced it planned to fix the issue by replacing all the valves with burst discs, which can relieve pressure from the pressurized system by bursting open but which won’t allow material such as propellant to travel into the system.

Hopefully the test will all go well and they will launch a crew sooner rather than later...