Author Topic: SNC Dream Chaser DISCUSSION Thread  (Read 646960 times)

Offline CameronD

  • Full Member
  • ****
  • Posts: 1374
  • Melbourne, Australia
    • Norton Consultants
  • Liked: 444
  • Likes Given: 325
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1960 on: 11/20/2017 02:45 AM »
It was well worth the wait to be sure... Note to ground crew "don't forget to wear your oven mitts"... ;D

ROTFLOL!! (You made me spill my coffee..)  ;D ;D
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline yg1968

  • Senior Member
  • *****
  • Posts: 9588
  • Liked: 1340
  • Likes Given: 850
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1961 on: 01/21/2018 02:34 AM »
It's not recent but I found this presentation on DC which is good:

http://ndiatvc.org/images/downloads/SMDWG_July_2016/ndia_space___missile_defense_wg_18_jul_16_vfinal2.pdf

Among other things, it states the following:

Quote
Mature Vehicle with All Major Risks Retired

-Hot fired ORBITEC Vortex engine propulsion system numerous times
« Last Edit: 01/21/2018 02:39 AM by yg1968 »

Offline Alpha Control

  • Veteran
  • Full Member
  • ****
  • Posts: 1187
  • Washington, DC
  • Liked: 126
  • Likes Given: 73
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1962 on: 01/21/2018 05:22 AM »
It's not recent but I found this presentation on DC which is good:

http://ndiatvc.org/images/downloads/SMDWG_July_2016/ndia_space___missile_defense_wg_18_jul_16_vfinal2.pdf

Among other things, it states the following:

Quote
Mature Vehicle with All Major Risks Retired

-Hot fired ORBITEC Vortex engine propulsion system numerous times

Thanks YG. I hadn't seen this before. Among the slides (some of which had very good graphics of Crew DC & Cargo DC), I caught that same thing you did, about the Orbitec Vortec engine testing (slide 19). 

I confess I'm not clear at this point - is Cargo DC using Orbitec Vortec engines for the RCS role? Or are they for the OMS role? (orbit adjustment/deorbit)?  Or none of the above?
Space launches attended:
Antares/Cygnus ORB-D1 Wallops Island, VA Sept 2013 | STS-123 KSC, FL March 2008 | SpaceShipOne Mojave, CA June 2004

Offline yg1968

  • Senior Member
  • *****
  • Posts: 9588
  • Liked: 1340
  • Likes Given: 850
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1963 on: 01/22/2018 12:13 AM »
Both, it seems. Orbitec was already doing the RCS prior to SNC aquiring them.

Quote
SNC has been working with ORBITEC for over three years. ORBITEC is the lead for the Environmental Control and Life Support Systems (ECLSS) and Thermal Control Systems (TCS) for SNC, providing reliable living conditions including temperature and humidity control to support the astronauts during their journeys on SNC's Dream Chaser® spacecraft. Recently, SNC selected ORBITEC to provide the RCS engines for Dream Chaser using green, nontoxic propellants. The flexibility of fuel and oxidizer options along with the ability to quickly scale engine size makes ORBITEC's Vortex technology the growing industry preferred choice for Reaction Control Systems (RCS), Upper Stage engines and potentially boost class engines.

https://www.sncorp.com/press-releases/snc-orbitec-acquisition/

Quote
Orbitec will produce the environmental control system that handles air and heat inside the Dream Chaser and rocket engine thrusters that will propel and steer the vehicle in space, Zamprelli said.

http://host.madison.com/wsj/business/orbitec-to-fly-high-in-sierra-nevada-s-dream-chaser/article_3b9aa641-e3ce-5d7e-8ead-da4908bd2c30.html
« Last Edit: 01/22/2018 12:54 AM by yg1968 »

Offline Rocket Science

  • Senior Member
  • *****
  • Posts: 8615
  • NASA Educator Astronaut Candidate Applicant 2002
  • Liked: 2666
  • Likes Given: 6833
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1964 on: 02/07/2018 10:13 PM »
Thank you for the great article gents and congrats on your first John! :)   Seems like we have turned a corner and momentum is beginning to build. Heady days for commercial space all around! 8)
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator, Vintage auto racer

Offline JohnR

  • Member
  • Posts: 30
  • Florida
  • Liked: 44
  • Likes Given: 10
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1965 on: 02/07/2018 10:24 PM »
Thank you for the great article gents and congrats on your first John! :)

Thank you for the kind words!

Offline Norm38

  • Full Member
  • ****
  • Posts: 1108
  • Liked: 471
  • Likes Given: 660
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1966 on: 02/07/2018 11:21 PM »
Very cool to hear this is flying to ISS soon.  I'd still love to see this architecuture combined with the 2nd stage to increase reuse, but baby steps.  But this is great to have.  If we can't have propulsive landings, I'll take a runway landing over ocean splashdowns.

Offline northenarc

  • Full Member
  • ****
  • Posts: 582
  • United States
  • Liked: 159
  • Likes Given: 350
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1967 on: 02/08/2018 01:19 AM »
  Well, welcome to the ISS club. They can always lower expectations for the first Dream Chaser landings by taking only trash back and calling them 'experimental' like SpaceX does for their boosters. Lifting bodies just make me a little nervous, maybe because I can't help thinking of The Six Million Dollar Man intro whenever I see the thing.  :o   

Offline Rocket Science

  • Senior Member
  • *****
  • Posts: 8615
  • NASA Educator Astronaut Candidate Applicant 2002
  • Liked: 2666
  • Likes Given: 6833
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1968 on: 02/08/2018 01:23 AM »
Can someone please refresh my memory (yeah, I'm old) on the main gear utilized on ALT-2 and source info. On  ALT-1 I know the F-5 gear was hydraulic and contamination caused the failure. On ALT-2 was it the same F-5 main gear only with electrical actuators? If I remember the plan for the orbital vehicle that the gear will be electrically actuated and will have bespoke main gear, not the F-5 as in ALT-2 correct?
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator, Vintage auto racer

Offline Lobo

  • Senior Member
  • *****
  • Posts: 6749
  • Spokane, WA
  • Liked: 551
  • Likes Given: 344
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1969 on: 02/08/2018 05:00 PM »
It looks like DC will now have folding wings to fit into the Atlas PLF (this may have happened awhile ago, I haven't been following DC very closely for awhile).

And will fly on Atlas with 5 SRB's and a new modified Centaur with two RL-10's.

Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

I wonder how far along ULA is in development of the 2-engine Centaur?  The investment may have already been spent so it may be too late to switch horses now.  Just seems like the Falcon is a more optimized LV for DC's needs, given it's thrust and propellant types than Atlas which is more optimized for payloads going beyond LEO with it's low thrust/high efficiency Centaur upper stage.

Offline PahTo

  • Full Member
  • ****
  • Posts: 1536
  • Seattle
  • Liked: 171
  • Likes Given: 513
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1970 on: 02/08/2018 05:07 PM »

I wonder how far along ULA is in development of the 2-engine Centaur?  The investment may have already been spent so it may be too late to switch horses now.  Just seems like the Falcon is a more optimized LV for DC's needs, given it's thrust and propellant types than Atlas which is more optimized for payloads going beyond LEO with it's low thrust/high efficiency Centaur upper stage.

Note the 2-engine Centaur (in the contemporary form, for lack of a better term) has been in development to support CST Starliner, so DC is not the only customer/reason.  Beyond that, Centaur 5 is the ultimate design path for ULA upper stage development wrt Centaur, leading to ACES, but now we're getting ahead of ourselves...

Online DaveS

  • Shuttle program observer
  • Senior Member
  • *****
  • Posts: 7865
  • Sweden
  • Liked: 383
  • Likes Given: 14
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1971 on: 02/08/2018 05:12 PM »
It looks like DC will now have folding wings to fit into the Atlas PLF (this may have happened awhile ago, I haven't been following DC very closely for awhile).

And will fly on Atlas with 5 SRB's and a new modified Centaur with two RL-10's.

Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

I wonder how far along ULA is in development of the 2-engine Centaur?  The investment may have already been spent so it may be too late to switch horses now.  Just seems like the Falcon is a more optimized LV for DC's needs, given it's thrust and propellant types than Atlas which is more optimized for payloads going beyond LEO with it's low thrust/high efficiency Centaur upper stage.
The original Centaur featured twin RL-10's (called Dual Engine Centaur). The Single Engine Centaur (SEC) was only introduced with the Atlas V. So SEC is the modification, not the DEC.
"For Sardines, space is no problem!"
-1996 Astronaut class slogan

"We're rolling in the wrong direction but for the right reasons"
-USA engineer about the rollback of Discovery prior to the STS-114 Return To Flight mission

Offline Coastal Ron

  • Senior Member
  • *****
  • Posts: 3929
  • I live... along the coast
  • Liked: 2611
  • Likes Given: 3346
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1972 on: 02/08/2018 05:42 PM »
Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

Not sure you've heard, but if a reusable Falcon 9 is not powerful enough for your needs, SpaceX now has a reusable launch vehicle called Falcon Heavy that can likely take care of your needs...  ;)

However I'm sure Sierra Nevada knows what their launch vehicle options are, and for whatever good reasons they have they have determined that Atlas V is their best choice. Which is fine with me, because I'm more interested in getting Dream Chaser into space than who takes them there!

Fingers crossed for my favorite LEO spacecraft to stay on schedule...
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline rayleighscatter

  • Full Member
  • ****
  • Posts: 1012
  • Maryland
  • Liked: 465
  • Likes Given: 221
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1973 on: 02/08/2018 08:36 PM »
It looks like DC will now have folding wings to fit into the Atlas PLF (this may have happened awhile ago, I haven't been following DC very closely for awhile).

And will fly on Atlas with 5 SRB's and a new modified Centaur with two RL-10's.

Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

I wonder how far along ULA is in development of the 2-engine Centaur?  The investment may have already been spent so it may be too late to switch horses now.  Just seems like the Falcon is a more optimized LV for DC's needs, given it's thrust and propellant types than Atlas which is more optimized for payloads going beyond LEO with it's low thrust/high efficiency Centaur upper stage.

I believe DC wouldn't fit inside Falcon's fairing.

Offline Lobo

  • Senior Member
  • *****
  • Posts: 6749
  • Spokane, WA
  • Liked: 551
  • Likes Given: 344
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1974 on: 02/08/2018 09:50 PM »

I believe DC wouldn't fit inside Falcon's fairing.

I think both the Atlas 5m and Falcon PLF's are about the same diameter?

Offline Lobo

  • Senior Member
  • *****
  • Posts: 6749
  • Spokane, WA
  • Liked: 551
  • Likes Given: 344
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1975 on: 02/08/2018 09:57 PM »
Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

Not sure you've heard, but if a reusable Falcon 9 is not powerful enough for your needs, SpaceX now has a reusable launch vehicle called Falcon Heavy that can likely take care of your needs...  ;)

However I'm sure Sierra Nevada knows what their launch vehicle options are, and for whatever good reasons they have they have determined that Atlas V is their best choice. Which is fine with me, because I'm more interested in getting Dream Chaser into space than who takes them there!

Fingers crossed for my favorite LEO spacecraft to stay on schedule...
Falcon Heavy?

Never heard of it...

 ;D

Yea, there's that.  I was just trying to keep things a little more apples-to-apples.
Although, what's the LEO capacity of the FH with a recovered center core, to the ISS inclination?  If you can't recover the center core, then no reason to use it vs. the single stick F9 I wouldn't think?

But yea, all your points are valid and I agree.  Things are progressing and I'm sure connections and calculations are all being made for the Atlas LV and there'd be a certain amount of backtracking to switch LV's.

Offline JAFO

  • Full Member
  • ****
  • Posts: 589
  • Liked: 218
  • Likes Given: 172
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1976 on: 02/09/2018 12:23 AM »
Ok, I'm confused. Will her first orbital flight be the demo to the ISS, or are they planning another orbital "flight to nowhere" without an ISS rendezvous to test her out? 
Anyone can do the job when things are going right. In this business we play for keeps.
— Ernest K. Gann

Offline Rocket Science

  • Senior Member
  • *****
  • Posts: 8615
  • NASA Educator Astronaut Candidate Applicant 2002
  • Liked: 2666
  • Likes Given: 6833
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1977 on: 02/09/2018 12:26 AM »
Ok, I'm confused. Will her first orbital flight be the demo to the ISS, or are they planning another orbital "flight to nowhere" without an ISS rendezvous to test her out?
My impression is the one flight cleared to ISS... Unless I'm confused as well! ;D
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator, Vintage auto racer

Offline rayleighscatter

  • Full Member
  • ****
  • Posts: 1012
  • Maryland
  • Liked: 465
  • Likes Given: 221
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1978 on: 02/09/2018 02:25 PM »

I believe DC wouldn't fit inside Falcon's fairing.

I think both the Atlas 5m and Falcon PLF's are about the same diameter?

I believe it was the length, not the diameter that was the limiting factor.

Offline Rocket Science

  • Senior Member
  • *****
  • Posts: 8615
  • NASA Educator Astronaut Candidate Applicant 2002
  • Liked: 2666
  • Likes Given: 6833
Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1979 on: 02/09/2018 02:29 PM »
From woods170 in the update thread:

"Between the 2013 and 2017 tests, a number of systems have changed on the Dream Chaser ETA including the main gear that is more advanced than that flown on the first test and is closer to the flight hardware. The ETA was also flying with upgraded space-rated avionics and flight software that will be used on operational Dream Chaser missions to the Space Station."

Bold mine:
To me it still looks like the F-5E main gear... Now what "advanced and closer" means is not actual final final flight hardware which is to be built by Triumphgroup... But thanks just the same... :)

BTW I own a 1969 Triumph GT6 produced by the wonderful craftsmen of the British car industry... What became of them?? :(
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator, Vintage auto racer

Tags: