Thanks for the article - but a Q: Was this a full size Dream Chaser or a sub-scale one? (The article did not specify - or I missed it)
Wow! I wish I'd have known, I'd have tried to arrange a chance to shoot pictures. Is the date of the drop test @ Edwards known?
Quote from: jimvela on 05/29/2012 09:26 pmWow! I wish I'd have known, I'd have tried to arrange a chance to shoot pictures. Is the date of the drop test @ Edwards known?Not known yet, but SNC have offered Lee Jay a tour and interview tomorrow! So more articles to come!
Not sure if this is just a full scale model or an actual spacecraft?
What is the purpose behind a captive test? Unless it's just to bake sure the hookups work before the drop test....
The kid in the video is exactly what I'd sound like if I was there
Quote from: JBF on 05/29/2012 09:53 pmWhat is the purpose behind a captive test? Unless it's just to bake sure the hookups work before the drop test....Verify the dynamics of the config before the drop test.
IIRC, the plan was to do low-altitude drops from the Sky Crane first, and then move on to higher altitude/speed drops from WK2.
IIRC, the plan was to do low-altitude drops from the Sky Crane first, and then move on to higher altitude/speed drops from WK2.Dropping from the Sky Crane is presumably lower cost, both from a rental and insurance point of view...
Quote from: simonbp on 05/29/2012 11:51 pmIIRC, the plan was to do low-altitude drops from the Sky Crane first, and then move on to higher altitude/speed drops from WK2.Dropping from the Sky Crane is presumably lower cost, both from a rental and insurance point of view...That’s what I said in the other thread Simon. Unmanned drop tests from Skycrane and manned drop tests from WK2. But Lee Jay can verify in person...
Quote from: Rocket Science on 05/29/2012 11:55 pmQuote from: simonbp on 05/29/2012 11:51 pmIIRC, the plan was to do low-altitude drops from the Sky Crane first, and then move on to higher altitude/speed drops from WK2.Dropping from the Sky Crane is presumably lower cost, both from a rental and insurance point of view...That’s what I said in the other thread Simon. Unmanned drop tests from Skycrane and manned drop tests from WK2. But Lee Jay can verify in person... I'm not going to Edwards!
When you speak with Mark?
Quote from: Rocket Science on 05/30/2012 12:00 amWhen you speak with Mark?Speak quietly so you don't wake me up.
Quote from: simonbp on 05/29/2012 11:51 pmIIRC, the plan was to do low-altitude drops from the Sky Crane first, and then move on to higher altitude/speed drops from WK2.That would explain it, but low-speed means DC is sub-stall at drop, and low-altitude means not a lot of time to recover before landing.
Great job on the article as usual Chris. Is this particular vehicle a mockup or an actual spacecraft (minus avionics thrusters ect)?
How many missions do they think they can get out of an airframe?
So was this a captive carry test of the HL-20 mock-up built back in 1990 by college students?
Quote from: manboy on 05/30/2012 01:08 pmSo was this a captive carry test of the HL-20 mock-up built back in 1990 by college students?No. This is the ETA built by SNC.
Quote from: Lee Jay on 05/30/2012 01:25 pmQuote from: manboy on 05/30/2012 01:08 pmSo was this a captive carry test of the HL-20 mock-up built back in 1990 by college students?No. This is the ETA built by SNC.Do we have a confirmation on that?
Quote from: FinalFrontier on 05/30/2012 03:58 amGreat job on the article as usual Chris. Is this particular vehicle a mockup or an actual spacecraft (minus avionics thrusters ect)? Engineering Test Article. Much closer to mockup than spacecraft.
It states “flight vehicle” in the NAASA press release and if you look closely in the video you can see control surfaces…
NASA.gov's got their own (short) article on this now:http://www.nasa.gov/exploration/commercial/crew/snc_captivecarry.html#
More than NASAWatch has. For all the talk that website does it is now only a cheerleading site for SpaceX and the current administration. I note there was no mention of the CST-100 drop test or the SNC test yet.
Quote from: Go4TLI on 05/31/2012 02:08 amMore than NASAWatch has. For all the talk that website does it is now only a cheerleading site for SpaceX and the current administration. I note there was no mention of the CST-100 drop test or the SNC test yet.If you can figure out how to spin this story to "see how much NASA sucks?" then it will be welcomed there. That's their role.
Quote from: QuantumG on 05/31/2012 02:12 amQuote from: Go4TLI on 05/31/2012 02:08 amMore than NASAWatch has. For all the talk that website does it is now only a cheerleading site for SpaceX and the current administration. I note there was no mention of the CST-100 drop test or the SNC test yet.If you can figure out how to spin this story to "see how much NASA sucks?" then it will be welcomed there. That's their role.I almost fell out of my chair laughing seeing NASA watch mentioned here again. That place is literally the "media matters" equivalent for spaceflight. Its been nearly two years since I saw them crop up in discussion here, thanks for that was a good laugh
I do wonder about the tiny vertical tail - it is so small that it *looks* like it would hardly give any aerodynamic benefit.
Just the opposite. An Engineering Test Article is typically a high-fidelity step toward the operational item. In a vehicle's case it is typically a pathfinder meant to be structurally similar to the intended production vehicle with similar mass properties and aerodynamics.Systems can and will very depending on the scope, nature and reason for the tests.
Quote from: Go4TLI on 05/31/2012 02:04 amJust the opposite. An Engineering Test Article is typically a high-fidelity step toward the operational item. In a vehicle's case it is typically a pathfinder meant to be structurally similar to the intended production vehicle with similar mass properties and aerodynamics.Systems can and will very depending on the scope, nature and reason for the tests.That would make it similar to the shuttle Enterprise.
Quote from: Lars_J on 05/31/2012 03:06 amI do wonder about the tiny vertical tail - it is so small that it *looks* like it would hardly give any aerodynamic benefit.I keep wondering about the lack of a body flap, both for pitch control and for shielding the docking ring during re-entry.
I believe the central vertical fin moves as a single unit. If so, that should give you quite a bit of control especially when hard over. IIRC a key function of this control surface is for yaw control in cross winds during landing, i.e. pointing straight down the runway. Can anybody confirm? As others have pointed out there are six other control surfaces in addition to this which act in sum to give the traditional rudder/aileron/elevator functions. Talking of crosswinds, X-24 was occasionally blown sideways during landing as it presented a big surface area to the side. The Dream Chaser will presumably face a similar challenge. Elsewhere people have wondered if steering is achieved by differential braking of the main landing gear. My guess is this technique would give you more ability to overcome this sort of crosswind problem, at least it would be better than small steerable nose wheels.As for body flaps, as others have noted these lie flush to the body and do not extend beyond the rear of the fuselage. I'm not sure why this is the case. If they were further back extending out (a la X-33) that would give a larger control moment, and would provide protection for the engine bells. There is a Q&A thread, perhaps this belongs there. http://forum.nasaspaceflight.com/index.php?topic=9921.new;topicseen#new
Elsewhere people have wondered if steering is achieved by differential braking of the main landing gear. My guess is this technique would give you more ability to overcome this sort of crosswind problem, at least it would be better than small steerable nose wheels.
The HL-20 certainly had an all-moving vertical fin - at least it did in the documents I'm reading... If Dream Chaser forgoes this, it would be one of the more significant aerodynamic changes. As a much lighter vehicle, my guess is cross wind constraints will be different to Shuttle. The total sideways surface area is less than The orbiter of course, but from the side those tip fins look like weather vanes. I think the gating factor is density, and Carbon composite DC will be less dense. Anyway, with enough wheel steering and yaw control I'm sure it can be managed.
Hi Robert, here are a few references to the moving rudder, all historical HL-20 stuff:http://dscb.larc.nasa.gov/DCBStaff/ebj/Papers/aiaa-91-2955-HL20simtools.pdf page 7,http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920021931_1992021931.pdf page 3,http://dscb.larc.nasa.gov/DCBStaff/ebj/Papers/TM-107580.pdf page 5.Interestingly, in the pictures of the flight test article it looks to me as though the rudder might not be one piece...
Not to spoil your reading fun, but they did test some Shuttle-like split-rudder speed brake configurations, and did not recommend implementing for HL-20.
If you look carefully at the back of DC you can see 4 rectangles that are the control surfaces responsible for pitch and roll very similar as was used on the X-24A.http://www.dfrc.nasa.gov/gallery/photo/X-24/HTML/E-23377.htmlhttp://www.vskylabs.com/vsl-techreports/martin-marietta-x-24a-reports/x-24-approach-flare-and-landing
Quote from: Rocket Science on 05/31/2012 12:03 pmIf you look carefully at the back of DC you can see 4 rectangles that are the control surfaces responsible for pitch and roll very similar as was used on the X-24A.http://www.dfrc.nasa.gov/gallery/photo/X-24/HTML/E-23377.htmlhttp://www.vskylabs.com/vsl-techreports/martin-marietta-x-24a-reports/x-24-approach-flare-and-landingNice catch! (And a plug that you can see the control surfaces much better in Lee Jay's photos on L2.)Correct me if I'm wrong, but when they finally drop, will this be the first large American lifting body to do a runway landing since X-24B? X-38 only landed on the lakebed under a parachute.
Quote from: simonbp on 06/01/2012 08:01 pmCorrect me if I'm wrong, but when they finally drop, will this be the first large American lifting body to do a runway landing since X-24B? X-38 only landed on the lakebed under a parachute.You are correct Simon! 38 years ago first concrete landing at Edwards!!
Correct me if I'm wrong, but when they finally drop, will this be the first large American lifting body to do a runway landing since X-24B? X-38 only landed on the lakebed under a parachute.
Quote from: Rocket Science on 06/01/2012 08:15 pmQuote from: simonbp on 06/01/2012 08:01 pmCorrect me if I'm wrong, but when they finally drop, will this be the first large American lifting body to do a runway landing since X-24B? X-38 only landed on the lakebed under a parachute.You are correct Simon! 38 years ago first concrete landing at Edwards!!The Shuttle doesn't count as a lifting body? Are the wings too large? Noel
Quote from: Rocket Science on 06/01/2012 08:15 pmQuote from: simonbp on 06/01/2012 08:01 pmCorrect me if I'm wrong, but when they finally drop, will this be the first large American lifting body to do a runway landing since X-24B? X-38 only landed on the lakebed under a parachute.You are correct Simon! 38 years ago first concrete landing at Edwards!!The Shuttle doesn't count as a lifting body? Are the wings too large?
This is what a real lifting-body shuttle looks like...
Quote from: jnc on 06/01/2012 09:50 pmThe Shuttle doesn't count as a lifting body? Are the wings too large? No and Yes.
The Shuttle doesn't count as a lifting body? Are the wings too large?
If you look carefully at the back of DC you can see 4 rectangles that are the control surfaces responsible for pitch and roll very similar as was used on the X-24A.
I think Robert was referring to the body flaps on the upper and lower surfaces of the rear fuselage.
Also, as a DoD (previously NASA) project, would SNC have access to lessons learned on the project?
Not to chase our own tails with arguments over definitions but...The X-37B did a runway landing at Edwards, so by the logic so in this thread so far, either its wings are too large for it to count as a lifting-body, and/or 11,000 lb doesn't count as 'heavy.'Definitions aside, some real questions: my guess is X-37B experience is relevant to DC, especially surrounding autoland. Do people feel it is too dissimilar aerodynamically for this to be the case? Also, as a DoD (previously NASA) project, would SNC have access to lessons learned on the project?
Just like the space shuttle before it, SNC's Dream Chaser will go through extensive testing to prove its wings will work....and is the only spacecraft under CCDev2 that incorporates wings
Quote from: Jorge on 06/02/2012 06:29 amQuote from: jnc on 06/01/2012 09:50 pmThe Shuttle doesn't count as a lifting body? Are the wings too large? No and Yes. They remind me of the wings on a penguin - insufficient to hold it aloft. I can't think what class to put it in other than 'lifting body' (and in fact, maybe not even in that, since some lifting bodies actually did generate enough lift to keep them aloft).
And *no* aircraft generates sufficient lift *without* *propulsion* to "hold itself aloft." They just have better glide ratios than the shuttle. Typically 20:1 for an airliner, compared to 4:1 for the shuttle.
Quote from: adrianwyard on 06/02/2012 02:47 pmI think Robert was referring to the body flaps on the upper and lower surfaces of the rear fuselage. I see some rectangles there, but they don't look like control surfaces to me. Perhaps they were locked down or not installed yet on the vehicle I saw. There's still some time before the ALT tests so that's a possibility.
PS: Now that I think about it, I think the point I was trying to make is that in general, one never saw the Shuttle do anything that increased its altitude while in the unpowered phase (well, maybe in the hypersonic phase it did, I don't know all the fine details of how they did that - I just remember the banked turns). That's more what I meant by "hold itself aloft".I assume that the Shuttle could generate enough lift (were it going fast enough) to pull up, and trade speed for altitude to gain altitude (in the unpowered mode), but I don't think they ever did so? That's more what I was thinking of when I compared it unfavourably to some of the experimental lifting bodies - 'never gained altitude'.
Quote from: Lee Jay on 06/02/2012 03:03 pmQuote from: adrianwyard on 06/02/2012 02:47 pmI think Robert was referring to the body flaps on the upper and lower surfaces of the rear fuselage. I see some rectangles there, but they don't look like control surfaces to me. Perhaps they were locked down or not installed yet on the vehicle I saw. There's still some time before the ALT tests so that's a possibility.You can see them moving in the scale model at 01:56 in the following video:As you say, perhaps they were not active on the very first test...
Re: X-37 and lifting bodies. It certainly looks like the X-37's wings provide the majority of the lift even if the body area is large by comparison, so this would make it not a lifting body. However, I've always been intrigued by the shaping of the fuselage at the rear, and assumed this was connected to lift somehow. (So far I've found nothing to back that up.)
Along a similar vein:WhiteKnight 3 plus what upper stage could provide a decent suborbital test for Dream Chaser?
Quote from: Danderman on 06/19/2012 07:28 pmAlong a similar vein:WhiteKnight 3 plus what upper stage could provide a decent suborbital test for Dream Chaser?I assume it could fire it's hybrid engines after it's released from the White Knight 2, and pretend it's a SS2.
That's an interesting idea. I'd feel more confident in the future of commercial projects like Dream Chaser if there were multiple revenue options beyond a small number of trips to the ISS for NASA.
transcontinental to a real destination at high-speed
I've previously suggested powered sub-orbital hops from WK2 - offered at a premium over SS2 tickets since DC is a 'real' spacecraft.
Quote from: adrianwyard on 06/26/2012 05:17 pmtranscontinental to a real destination at high-speedNo business case for that.
Quote from: Jim on 06/26/2012 05:52 pmQuote from: adrianwyard on 06/26/2012 05:17 pmtranscontinental to a real destination at high-speedNo business case for that.Unfounded speculation
Quote from: adrianwyard on 06/26/2012 05:17 pm I've previously suggested powered sub-orbital hops from WK2 - offered at a premium over SS2 tickets since DC is a 'real' spacecraft.Not really, the flight profile would be the same for either spacecraft.
Re "no business case"Well if we want to follow this general idea forward and get to real-world operational and regulatory details, then I could well believe the business becomes iffy. Predicting the future in detail is hard.I thought you were saying that there's no case for high-speed travel per se. I personally paid the big bucks to travel on Concorde, and definitely felt as though I got my money's worth. As you say, the first hurdle is the oft-quoted assessment that you need near-orbital velocity to get any useful (marketable) distance. If that's derived unambiguously from the physics, then that would a good reason to move on.
Quote from: Jim on 06/26/2012 05:54 pmQuote from: adrianwyard on 06/26/2012 05:17 pm I've previously suggested powered sub-orbital hops from WK2 - offered at a premium over SS2 tickets since DC is a 'real' spacecraft.Not really, the flight profile would be the same for either spacecraft.What's the proposed duration of a sub-orbital flight ? Any more takers for anOrbital flight that does 2-3 full orbits before landing fairly close to the launch site ?
Quote from: adrianwyard on 06/26/2012 06:19 pmRe "no business case"Well if we want to follow this general idea forward and get to real-world operational and regulatory details, then I could well believe the business becomes iffy. Predicting the future in detail is hard.I thought you were saying that there's no case for high-speed travel per se. I personally paid the big bucks to travel on Concorde, and definitely felt as though I got my money's worth. As you say, the first hurdle is the oft-quoted assessment that you need near-orbital velocity to get any useful (marketable) distance. If that's derived unambiguously from the physics, then that would a good reason to move on.It is. Orbital velocity is around 25.8 kfps; a transatlantic flight requires about 18.4 kfps (see, for example, the STS-135 3-engine-out TAL boundary, below). SS2/WK2 will be in the 3-4 kfps range.
. I personally paid the big bucks to travel on Concorde, and definitely felt as though I got my money's worth.
Quote from: adrianwyard on 06/26/2012 06:19 pm. I personally paid the big bucks to travel on Concorde, and definitely felt as though I got my money's worth. Joyride and not a business decision