Author Topic: Sierra Space Dream Chaser UPDATE Thread (was SNC)  (Read 740625 times)

Offline Chris Bergin

Re: SNC Dream Chaser UPDATE Thread
« Reply #220 on: 08/26/2013 01:14 pm »
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Online Lee Jay

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Re: SNC Dream Chaser UPDATE Thread
« Reply #221 on: 08/26/2013 01:23 pm »
Good article, Chris.  I wonder how many people are going to freak-out when they see DC heading for the Earth nose-down for a few seconds before the pull-up.  Let's just hope that the pull-up and landing result in the ability to further use the aircraft!

Offline Archibald

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Re: SNC Dream Chaser UPDATE Thread
« Reply #222 on: 08/26/2013 02:32 pm »
This is very well said

Quote
Often cited as “handing over the keys to Low Earth Orbit (LEO)”, NASA is deeply involved in providing funding and expertise to drive both new and old space companies into providing domestic cargo and crew capabilities to the International Space Station (ISS).

NASA used it best asset - the ISS - to provide a destination for newspace companies.
Today it can be said that, without ISS cargo (and soon crew) supply, private companies wouldn't be on the way to HSF. For example, orbital tourism by itself would not have been sufficient to sustain Dragon (or Dream Chaser) development, not with a dozen of $30 million tickets spread over decades.
I say: this is NASA job as per its charter. To help develop space as, many decades ago, NACA helped aeronautics to develop.

Quote
handing over the keys

I like this expression. Controversial perhaps, but it summarizes the ongoing situation very well.
« Last Edit: 08/26/2013 02:36 pm by Archibald »
Han shot first and Gwynne Shotwell !

Offline vt_hokie

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Re: SNC Dream Chaser UPDATE Thread
« Reply #223 on: 08/26/2013 06:46 pm »
Overall review of recent and upcoming commercial work:

http://www.nasaspaceflight.com/2013/08/countdowns-testing-commercial-space-steps-gear/

I like that you pull no punches in your apt description of the post-shuttle transition.  But what concerns me most is that while the commercial crew program is progressing, under the current funding scenario it is progressing toward a dead end for two out of the three contenders. So as the down-select approaches we continue to throw taxpayer dollars down the drain on new systems that will never see the light of day.

Offline Robotbeat

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Re: SNC Dream Chaser UPDATE Thread
« Reply #224 on: 08/26/2013 06:50 pm »
Overall review of recent and upcoming commercial work:

http://www.nasaspaceflight.com/2013/08/countdowns-testing-commercial-space-steps-gear/

I like that you pull no punches in your apt description of the post-shuttle transition.  But what concerns me most is that while the commercial crew program is progressing, under the current funding scenario it is progressing toward a dead end for two out of the three contenders. So as the down-select approaches we continue to throw taxpayer dollars down the drain on new systems that will never see the light of day.
Risk-reduction. Besides, it's still possible these systems may eventually see the light of day. Bigelow's inflatable was a canceled NASA project. Even SpaceX's Merlin's early turbopump has intellectual heritage from part of a canceled NASA project. DC-X was cancelled, but inspired Grasshopper and Blue Origin. Blue Origin won't be picked for commercial crew, but the funding from NASA is helping them with their further efforts.

It's not for naught.
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 newpylong

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Re: SNC Dream Chaser UPDATE Thread
« Reply #225 on: 08/26/2013 08:21 pm »
Could not have said it any better. If we can only afford one final contract, such is life. At least we got to nurture 3 different vehicles forward, and the private spaceflight industry is a hell of a lot further along than it was (nowhere?) pre-COTS/Commercial Crew. One of the goals of NASA is not only to provide science themselves but to be a catalyst like this.
« Last Edit: 08/26/2013 08:23 pm by newpylong »

Offline Bob Shaw

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Re: SNC Dream Chaser UPDATE Thread
« Reply #226 on: 08/26/2013 08:39 pm »
As regards the wish - stated earlier - to see a DreamChaser named 'Enterprise' I, for one would like to see a similar vehicle named 'Basil'. Or perhaps 'Sybil'. Not Polly, though, that would be silly.

Offline JasonAW3

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Re: SNC Dream Chaser UPDATE Thread
« Reply #227 on: 08/27/2013 05:37 pm »
If I remember correctly, should either a Delta or Atlas not be available, (or the mythical SLS) the Dreamchaser could be launched on a Falcon 9, or was that the Falcon Heavy?

     Next question; Was the Dreamchaser only designed for a LEO reentry or could it handle a BEO reentry?

Looked but couldn't find these answers.

Jason
My God!  It's full of universes!

Offline Lurker Steve

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Re: SNC Dream Chaser UPDATE Thread
« Reply #228 on: 08/27/2013 09:20 pm »
Good article, Chris.  I wonder how many people are going to freak-out when they see DC heading for the Earth nose-down for a few seconds before the pull-up.  Let's just hope that the pull-up and landing result in the ability to further use the aircraft!

I assume they will have run thru the drop test about 10,000 times in the simulator before they try it on the actual DC, right ?

Offline Heinrich

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Re: SNC Dream Chaser UPDATE Thread
« Reply #229 on: 09/01/2013 07:03 pm »
As regards the wish - stated earlier - to see a DreamChaser named 'Enterprise' I, for one would like to see a similar vehicle named 'Basil'. Or perhaps 'Sybil'. Not Polly, though, that would be silly.

Why not Polly? I wouldn't call it Manuel though.

How would they 'launch' it for the free flight landing test? Skycrane again?

Offline banjo

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Re: SNC Dream Chaser UPDATE Thread
« Reply #230 on: 09/01/2013 08:33 pm »
don't mention the war!   sorry, i couldn't resist.  it would take a lot to top the spectacle of grasshopper flying sideways; i think the dreamchaser pad abort test may do it.

Offline AnalogMan

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Re: SNC Dream Chaser UPDATE Thread
« Reply #231 on: 09/12/2013 10:41 pm »
Simulator Fitted with Dream Chaser Canopy Model
Thurs, 12 Sept 2013 3:27:30 PM EDT

Simulation technicians Brent Bieber, left, and Dennis Pitts install a boilerplate Dream Chaser canopy structure over the cockpit of a flight simulator in the simulation laboratory at NASA's Dryden Flight Research Center in California. The modification will give Dream Chaser pilot-astronauts a more representative view of the actual flight profiles the spacecraft would fly during piloted approach and landing tests. Sierra Nevada Corporation's Space Systems division is conducting uncrewed captive- and free-flight approach and landing tests of its Dream Chaser at Dryden during the summer and fall. Photo credit: NASA/Ken Ulbrich

Offline AnalogMan

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Re: SNC Dream Chaser UPDATE Thread
« Reply #232 on: 09/23/2013 10:49 pm »
Langley Tests Dream Chaser's Thermal Dynamics
Sept 23, 2013 Sasha Congiu, NASA's Langley Research Center

When Sierra Nevada Corporation’s (SNC) Dream Chaser spacecraft flies through the atmosphere, it will encounter a wide variety of environmental conditions. Any spacecraft traveling at hypersonic velocities must have a robust thermal protection system (TPS) to protect astronauts and cargo from the extreme temperatures associated with ascent and re-entry.

NASA's Langley Research Center in Hampton, Va., recently conducted hypersonic testing of Dream Chaser models for SNC as part of the agency's Commercial Crew Program in order to obtain necessary data for the material selection and design of the TPS. SNC conducted wind tunnel tests to reduce risk and improve the reliability of the Dream Chaser TPS under milestone eight of the agency's Commercial Crew Integrated Capability (CCiCap) initiative.

The Dream Chaser, based on NASA's HL-20 lifting-body design, combines years of NASA analysis and wind tunnel research with SNC engineering, resulting in a reusable spacecraft that could ferry astronaut crews to and from low-Earth orbit. The HL-20 was a space plane concept studied by NASA at Langley during the early 1990s as a safe and affordable personnel launch system for trips to low-Earth orbit.

 “This system, along with other Commercial Crew Program partners' systems, gets us one step closer to launching people back into space onboard American made spacecraft,” said Karen Berger, Langley aerospace engineer.

The Dream Chaser models tested were approximately 10 inches long and made of cast ceramic. They were fabricated at Langley to measure heating levels the Dream Chaser spacecraft would experience during re-entry, including the lower- and upper-body flaps, elevons and a rudder. As with all spacecraft development, the testing required attention to details, from the design of the model to the complexity of data collection and analysis.

The heating data were measured using phosphor thermography, which allowed researchers to see a global view of the surface being investigated. Each pixel in the image acts as its own data point.

“It allows us to see very complex and intricate flow patterns,” Berger said.

With this technique, an image of each model is acquired before each wind tunnel run and then multiple images are taken during the run itself.

“Using calibrations performed prior to the test and calibrating with the color change after the test run, the temperatures and heating rate for each image can be computed,” Berger said.

The temperatures and heating rate information then will be used to help determine appropriate thermal protection system materials and also will be compared with computational predictions. Hypersonic testing of the Dream Chaser spacecraft will enable NASA and SNC teams to advance their knowledge and understanding of the environments that the vehicle will encounter during ascent and re-entry.

“We can use that knowledge to better develop new vehicles in the future, whether they are NASA vehicles or we are working with our commercial partners,” Berger said.

http://www.nasa.gov/content/langley-tests-dream-chasers-thermal-dynamics/

Photo Captions:

Top: An engineer at NASA's Langley Research Center prepares a 10-inch ceramic model of the Sierra Nevada Corporation Dream Chaser spacecraft for high-speed wind tunnel testing. Image Credit: NASA/David Bowman

Bottom: Multiple images are taken of the Sierra Nevada Corporation Dream Chaser model during each wind tunnel run to measure the spacecraft's temperature and heating rate. Image Credit: NASA/David Bowman

Offline AnalogMan

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Re: SNC Dream Chaser UPDATE Thread
« Reply #233 on: 09/23/2013 10:51 pm »
Video to go with the above update.


Offline adrianwyard

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Re: SNC Dream Chaser UPDATE Thread
« Reply #234 on: 09/23/2013 11:57 pm »
I'm intrigued by the shape of the cowling around the engine nozzles. This has been depicted in models before, but not in CG.

http://www.nasa.gov/sites/default/files/dream_chaser_testing.jpg?itok=KzdVUkwn

After scratching my head for a while I've come up with a theory on what's going on: this is thermal protection for the nozzle during re-entry (they're exposed to the airstream as the nose is pointed up). However, these engines are supposedly support thrust vectoring, and a fixed TPS cowling would prevent movement, so what we see here are separate rings of TPS that can move independent of each other to allow the nozzle to gimbal.
« Last Edit: 09/24/2013 02:15 am by adrianwyard »

Offline Lurker Steve

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Re: SNC Dream Chaser UPDATE Thread
« Reply #235 on: 09/24/2013 01:58 am »
I'm a little surprised they haven't done a material selection for the TPS yet. Maybe there's an error in the announcement ?

Isn't there a bit of weight difference between the various choices, and that would have an effect on other design decisions ?

Offline BrightLight

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Re: SNC Dream Chaser UPDATE Thread
« Reply #236 on: 09/24/2013 02:07 pm »
I'm a little surprised they haven't done a material selection for the TPS yet. Maybe there's an error in the announcement ?

Isn't there a bit of weight difference between the various choices, and that would have an effect on other design decisions ?
I too am a little surprised, I thought that the TPS was already selected. Maybe this is verification of choices or analysis of alternatives?

Offline Lurker Steve

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Re: SNC Dream Chaser UPDATE Thread
« Reply #237 on: 10/08/2013 11:59 pm »
Any news of additional captive carry tests during the month of September ?

Offline russianhalo117

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Re: SNC Dream Chaser UPDATE Thread
« Reply #238 on: 10/09/2013 04:14 pm »
Any news of additional captive carry tests during the month of September ?
Not from NASA because its shut down because of the nearly complete polarization of the current US Congress. I am not sure about SNC though.

Online Lee Jay

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Re: SNC Dream Chaser UPDATE Thread
« Reply #239 on: 10/09/2013 05:29 pm »
Any news of additional captive carry tests during the month of September ?

They couldn't get a helicopter.  Now Dryden is closed for the government shutdown.

 

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