Author Topic: Dream Chaser making impressive progress ahead of CCDev-3  (Read 213676 times)

Offline sanman

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #280 on: 06/02/2012 05:55 pm »


The HL-10, a forerunner of DreamChaser, had a needle-nose on it. I'd like to ask if DreamChaser could be given a needle-nose just for the purpose of putting a camera out there near its tip, protruding beyond the plasma envelope during re-entry, so that clear video footage of the descent from orbit could be taken.

Would that be possible?

Offline Lurker Steve

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #281 on: 06/02/2012 06:04 pm »
The video says "No solid strapons" and "no abort blackzones." They are responding to ATK on the black zones and taking shots at Boeing for the solid strapon (the CST-100 uses the Atlas V 412; DC uses the Atlas V 402).
It also said, that their LAS didn't need that much thrust, because Atlas 402 has thrust termination. I wonder if this means that their LAS won't support an Atlas 412. That would be a huge risk on the mass margins. Meanwhile, CST-100 could simply do a 422. I.e., CST has the risk of being more expensive, while DC would be sort of incompatible. Am I reading this right?

Does the "base" CST-100 weight that much more than Dreamchaser, where it needs the strap-on ? These are crew vehicles, so the weight shouldn't vary that much. If they design a cargo version, it may weight more, but we don't launch crew and cargo at the same time, so the LAS isn't an issue, right ?

I don't believe any of the current vehicles with a "pusher" LAS have enough energy to escape Liberty, but that's Liberty design issue.

F9 might be an issue for both CST-100 and DreamChaser since the current SpaceX second stage is no where close to the dual-engine Centaur. It's probably an issue with Antares as well, although I haven't heard of anyone mentioning Antares with regards to commerical crew. Is it possible to Human rate their launcher ? Obviously Orbital didn't propose it as part of their Commerical Crew bid.

Offline Jim

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #282 on: 06/02/2012 06:05 pm »


The HL-10, a forerunner of DreamChaser, had a needle-nose on it. I'd like to ask if DreamChaser could be given a needle-nose just for the purpose of putting a camera out there near its tip, protruding beyond the plasma envelope during re-entry, so that clear video footage of the descent from orbit could be taken.

Would that be possible?

NO.  The needle-nose was for subsonic testing and had weather vane type angle of attach and side slip sensors on it.

The needle nose would have it own plasma envelop and also would burn off.

Offline Helodriver

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #283 on: 06/02/2012 06:18 pm »


The HL-10, a forerunner of DreamChaser, had a needle-nose on it. I'd like to ask if DreamChaser could be given a needle-nose just for the purpose of putting a camera out there near its tip, protruding beyond the plasma envelope during re-entry, so that clear video footage of the descent from orbit could be taken.

Would that be possible?


The needle nose you refer to is a pitot-static boom, a common addition to aircraft when undergoing flight test. Its there to get accurate readings of airspeed, sideslip, and angle of attack that are unaffected by the airflow around the vehicle's body and control surfaces. Typically once the airflow and its effect on installed instrumentation are better understood, the protruding boom is removed and less obtrusive body mounted sensors are used for operational flights.

Had the HL-10 actually been a spacefaring vehicle, the boom would not have been there. Such a boom would experience extreme heating and force during a reentry and would have to me made of exceptionally durable material to survive, as would any camera attached to it. The boom itself would develop its own plasma sheath, albeit smaller, during the reentry.

Offline adrianwyard

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #284 on: 06/02/2012 06:21 pm »
I think sanman might be talking about an airspike, the kind that is used for Trident ascent? This isn't applicable to HL-10 or DC as the spike would not be ahead of the entry airstream if placed on the nose and pointing 'forwards' along the length of the vehicle.
« Last Edit: 06/02/2012 06:27 pm by adrianwyard »

Offline Rocket Science

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #285 on: 06/02/2012 06:26 pm »
It is just as Jim said. It was a pitch-yaw air data test boom…
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator

Offline Lee Jay

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #286 on: 06/02/2012 06:29 pm »
SNC's DC provides a spacecraft that is much more dissimilar to Dragon than is CST-100.

That is not a consideration.

SNC thinks it is.

Offline yg1968

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #287 on: 06/02/2012 08:23 pm »
SNC's DC provides a spacecraft that is much more dissimilar to Dragon than is CST-100.

That is not a consideration.

It actually is a consideration. For CCDev, Phil McAlister said that NASA could consider choosing different kind of spacecrafts in their portfolio. He said that it's kind of like having a car and a pick-up truck.
« Last Edit: 06/02/2012 09:05 pm by yg1968 »

Offline simonbp

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #288 on: 06/03/2012 03:19 am »
Yeah, both the formal public rational for the CCDEV-2 selection and the scuttlebutt implies that for at least that round they wanted at least one runway-landing vehicle (meaning a choice between SNC and OSC). Of course, that was the thinking when they could put funds into three major vehicles (Blue Origin was a low-cost aberration). If they're down to two vehicles, the same logic may not apply.

Offline Seattle Dave

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #289 on: 06/03/2012 05:35 am »
Just so you know, we'll have two articles on SNC next week, following Lee Jay's visit to see Dream Chaser on behalf of NSF. Lots of good stuff coming! :)

No kidding. Just been through the L2 DCSS content. It's a Dream Chaser Treasure Trove! :o

Offline zerm

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #290 on: 06/04/2012 11:23 pm »
As a huge lifting body fan since the early 1970s, I cannot wait to see this puppy fly. There is something to be said for coming back from space and then stepping out onto a runway to walk away from your vehicle that just seems to be the way to go to and from LEO. The addition of non-toxic RCS is also just terrific for runway ops. DC is shaping up to be a very smart way to go.

Dale Reed smiles from above.

Offline hkultala

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #291 on: 06/06/2012 06:46 am »
DreamChaser is planned to use Atlas V 402 with no boosters, and an upper stage with more thrust.

And Dreamchaser itself has relatively big engines.

To me this sound like:

The carrier rocket is lifting Dreamchaser to only about 80-90% of orbital velocity.
Dreamchaser itself will act as 3rd stage, using own engines to reach orbit.

Am I correct?
« Last Edit: 06/06/2012 06:46 am by hkultala »

Offline simonbp

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #292 on: 06/06/2012 03:50 pm »
I think so. The images SNC has released do show the hybrids firing right after separation from the Centaur. That might be artistic license, but it does make sense. If nothing else, burning through the abort propellant would make the vehicle a bit easier to maneuver for docking.

Offline Chris Bergin

Already writing an article on this with some of Lee Jay's interview (most will be in a standalone article at the end of the week)

June 06, 2012

Trent J. Perrotto
Headquarters, Washington                                   
202-358-0321
[email protected]

Candrea Thomas       
Kennedy Space Center, Fla.       
321-867-2468
[email protected]

Sierra Nevada Corporation Space Systems
720-407-3193
[email protected]


RELEASE: 12-186

NASA PARTNER SIERRA NEVADA COMPLETES PRELIMINARY DESIGN REVIEW OF DREAM CHASER VEHICLE TO TRANSPORT ASTRONAUTS

LOUISVILLE, Colo. -- Sierra Nevada Corporation (SNC) Space Systems has
successfully completed a preliminary design review (PDR) of the
design, architecture and performance of its Dream Chaser orbital crew
vehicle. This marks a new milestone in the company's effort to
develop transportation for astronauts to low Earth orbit and the
International Space Station.

SNC is one of several companies working to develop commercial crew
transportation capabilities under the Commercial Crew Development
Round 2 (CCDev2) agreement with NASA's Commercial Crew Program (CCP).
The goal is to help spur innovation and development of new spacecraft
and launch vehicles from the commercial industry to develop safe,
reliable and cost-effective capabilities to transport astronauts to
low Earth orbit and the space station. The Dream Chaser is designed
to carry as many as seven astronauts to space. It is the only
spacecraft under CCDev2 that uses wings and is designed to land on a
conventional runway.

"As CCP's partners meet these critical milestones, we are moving in
the right direction in our combined effort to advance commercial
capabilities that could eventually transport NASA astronauts," NASA
CCP Program Manager Ed Mango said.

This marks the 17th milestone to be completed by SNC during CCP's
initial two development phases. The PDR included a review of the
entire orbital flight program, including the Dream Chaser spacecraft,
and associated mission and ground systems. The company also reviewed
the spacecraft's compatibility with its initial launch vehicle, the
United Launch Alliance Atlas V rocket.

"Our program includes 12 industrial partners, 7 NASA Centers and 3
universities from over 20 states who helped us achieve two major
program milestones this week. With the completion of PDR and the
beginning of our vehicle's flight test program, the Dream Chaser
Program has now entered the next phase of its development. We are
proud to be included with the other CCDev companies in developing a
US crew capability to low earth orbit," said Mark Sirangelo,
Corporate Vice President and head of SNC's Space Systems.

The final PDR board meeting was conducted shortly after the company
successfully completed a captive-carry test of its full-scale Dream
Chaser test flight vehicle May 29. The flight met all its test goals
and moved the program a step closer to preparing the vehicle for an
autonomous approach and landing test scheduled for later this summer.


All of NASA's industry partners, including SNC, continue to meet their
established milestones in developing commercial crew transportation
capabilities.

NASA also is developing the Orion spacecraft and Space Launch System
(SLS), a crew capsule and heavy-lift rocket that will provide an
entirely new capability for human exploration beyond low Earth orbit.
Designed to be flexible for launching spacecraft for crew and cargo
missions, SLS and Orion will expand human presence beyond low Earth
orbit and enable new missions of exploration across the solar system.
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Offline MikeAtkinson

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #294 on: 06/06/2012 05:39 pm »
Congratulations to Sierra Nevada on passing the PDR.

In my view a necessary (but not sufficient) condition for CCiCap was passing this PDR.

Offline Chris Bergin

Article for the PDR...
http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/

Will give it a standalone as I want to build the threads for this vehicle and create its own section :)
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Offline yg1968

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #296 on: 06/07/2012 12:32 am »
Article for the PDR...
http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/

Will give it a standalone as I want to build the threads for this vehicle and create its own section :)

It's not my call to make but I would wait to see if DC gets chosen for CCiCap before creating a new section. Otherwise, you will have to create new sections for Boeing and Blue Origin too. 

Offline zaitcev

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #297 on: 06/07/2012 07:17 pm »
The carrier rocket is lifting Dreamchaser to only about 80-90% of orbital velocity.
Dreamchaser itself will act as 3rd stage, using own engines to reach orbit.

If I remember right, originally it was not the plan. The older DC with "bumper car" nose was lofted by a 432 Altlas. Getting rid of the solids helps with human-rating the booster and reduces the requirements for LAS. The resulting capacity shortfall is addressed by firing the DC's engines. Someone who's handy with The Spreadsheet can probably calculate the exact amount of velocity that they impart.

Offline Chris Bergin

So I'm going to do two more (short term) on DC, as opposed to one big feature next, as there's a lot on the flight testing (today) and then we have the in space stuff we're going to get a bit more on for next week. :)
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Offline BrightLight

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Re: Dream Chaser making impressive progress ahead of CCDev-3
« Reply #299 on: 06/09/2012 03:32 am »
More articles  :)
Flight testing today  ;D

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