Author Topic: Dream Chaser aims to use Space Shuttle’s legacy to its advantage  (Read 15921 times)


Offline RocketmanUS

That was read differently than other articles you have written.  8)
 

Hopefully they will get more money and there will be no down select. As I do hope the three teams all do well with the money they have been awarded so far.

How much do they estimate they will need till first launch?

If Atlas V is retired in the future for some reason, is there plans for another launcher that can bring Dream Chaser to orbit?

What names should be given to each new mini shuttle?

« Last Edit: 08/18/2012 05:05 AM by RocketmanUS »
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Offline Lars_J

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As far as I know the Shuttles were not lifting bodies.

Offline mikes

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Quote
"There’s never been a capsule – over the 60 years of its operation – that has returned to space after coming back home"

Gemini 2

Offline john smith 19

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As far as I know the Shuttles were not lifting bodies.
Correct. The Orbiters have a clearly separation between the wing and the fuselage. When push came to shove NASA did not have enough confidence in the concept to bet the Agency on it. They felt the risk/reward balance was just too high.

However it could be said that *all* NASA crewed orbital vehicles were "lifting bodies" in the sense the all derived some (all in the case of Gemini & Apollo) lift from their body. Only Mercury was a true "ballistic" capsule (probably because they figured just getting it into space was going to be hard enough) with no lift.

AFAIk the *only* true lifting bodies to achieve orbit were under the ASSET and PRIME programmes of the 1960's (and I'm hazy on one of them being an LB rather than a conventional wing/fuselage. I'd need to checkmy copy of  "Facing the Heat Barrier" SP-2007-4232 to confirm).

While DC has a lot of design heritage and probably draws on a long *systems* legacy it's implementation and concept is quite "heroic" (first composite construction human rated lifting body *ever*).

I believe that *all* 3 concepts are strong enough to get certification to go to ISS. The joker in this pack will be the "Certification" process, which NASA seem adamant will be under FAR25 rules, which may sink *all* the bidders under a superstructure of endless paperwork and *forced* changes to the design.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Rocket Science

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Nice article Chris. :) There was a Gemini capsule that flew twice to space unmanned, so I guess for Mark that didn’t count. ;)  For all you non-believers, the Shuttle was a winged lifting body, it’s not all just black or white…

http://space.skyrocket.de/doc_sdat/gemini-b.htm

http://quest.arc.nasa.gov/aero/events/regimes/space.html
« Last Edit: 08/18/2012 11:56 AM by Rocket Science »
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Offline Orbiter

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I could tell that this was a Chris Bergin article before I even read who wrote it :) nice to see the shuttle living on in some way in terms of actual operations. Needless to say, I look forward to seeing a glider land into KSC from space again soon.

Orbiter
Attended space missions: STS-114, STS-124, STS-128, STS-135, Atlas V "Curiosity", Delta IV Heavy NROL-15, Atlas V MUOS-2, Delta IV Heavy NROL-37, SpaceX CRS-9, SpaceX JCSAT-16, Atlas V GOES-R, SpaceX SES-11.

Offline vt_hokie

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My biggest fear is that we spend all these taxpayer dollars on three worthy systems only to waste most of the effort. Talk of a downselect to one provider makes me nervous.

Offline Lee Jay

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Quote
"There’s never been a capsule – over the 60 years of its operation – that has returned to space after coming back home"

Gemini 2


Both suborbital, right?

Offline Rocket Science

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Quote
"There’s never been a capsule – over the 60 years of its operation – that has returned to space after coming back home"

Gemini 2


Both suborbital, right?
I know Gemini 2 was and have not located the details of the Gemin B flight yet... It is on display at the Cape Canaveral Air Force Museum, but you probably know that. If anyone knows please enlighten me, ;)

http://forum.nasaspaceflight.com/index.php?topic=26906.0
http://historicspacecraft.com/Gemini_Capsules.html\
http://www.space1.com/pdf/news1096.pdf

And now back to Dream Chaser... ;D
"The laws of physics are unforgiving"
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Online douglas100

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Students of the Soviet space program may be able to confirm or deny this, but I seem to remember reading somewhere that some Vostok style capsules used in various Earth observation programs were reused.
Douglas Clark

Offline Star One

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My biggest fear is that we spend all these taxpayer dollars on three worthy systems only to waste most of the effort. Talk of a downselect to one provider makes me nervous.

Hopefully it isn't something that will come to pass and we are left with at least two systems to use.

Offline Moe Grills

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As far as I know the Shuttles were not lifting bodies.

Pardon me, but what is you definition of 'lifting bodies'?

I seem to recall that none of the returning shuttles landed
like a plummeting rock.

Offline strangequark

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As far as I know the Shuttles were not lifting bodies.

Pardon me, but what is you definition of 'lifting bodies'?

I seem to recall that none of the returning shuttles landed
like a plummeting rock.

Lift provided by the main body of the vehicle, versus distinctly separate fuselage and wings. Shuttle was a little ambiguous, however

Offline zerm

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Most elevated discussions concerning Lifting Bodies revolve around a given "Shape" or "the shape" and outside of that it depends on who is doing the talking. I generally stick to what Dale Reed set as the foundation. He, 100% connects the shuttle orbiter shapes to the assorted lifting body breeds.

Of course it also comes down to similar discussions as to what a wing actually is. Some insist that it has to be cambered and thus providing lift, yet lift can be generated by a flat plate or even a turning tubular shape et.al.

IMO, since Dale Reed, the father of lifting bodies, links the shuttle shapes as a form of lifting body- so it is... period. Read his book and decide for yourself.

Milt Thompson, however, was of the opinions that only the lifting bodies based on the M2 shape were "true lifting bodies" so, there are other well informed folks who have had a more narrow view.

BTW- if you do not know who the two people I've cited here are- you would do well to find out before posting farther.

Offline mr. mark

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Remember capsules provide lift as well.

"The Apollo capsules were guided through the atmosphere — the center of mass of the capsule was offset from the center line. This angled the capsule's passage through the air, providing a sideways lift. Rotational thrusters were used to change the lift vector, allowing the capsule to be steered under either automatic or manual control". -  Wikipedia.com

 

Offline spectre9

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Ok zerm took your advice and looked it up.

Here's a couple of good links I found. I didn't know who these guys were before so thanks for enlightening me.  ;D

http://www.nasa.gov/centers/dryden/news/NewsReleases/2005/05-13_prt.htm

http://www.nasa.gov/centers/dryden/news/Biographies/Pilots/bd-dfrc-p018.html

Offline Patchouli

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Students of the Soviet space program may be able to confirm or deny this, but I seem to remember reading somewhere that some Vostok style capsules used in various Earth observation programs were reused.

It was the Soviet TKS VA capsule that was reusable.
« Last Edit: 08/19/2012 05:50 AM by Patchouli »

Offline GClark

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Most elevated discussions concerning Lifting Bodies revolve around a given "Shape" or "the shape" and outside of that it depends on who is doing the talking. I generally stick to what Dale Reed set as the foundation. He, 100% connects the shuttle orbiter shapes to the assorted lifting body breeds.

Of course it also comes down to similar discussions as to what a wing actually is. Some insist that it has to be cambered and thus providing lift, yet lift can be generated by a flat plate or even a turning tubular shape et.al.

IMO, since Dale Reed, the father of lifting bodies, links the shuttle shapes as a form of lifting body- so it is... period. Read his book and decide for yourself.

Milt Thompson, however, was of the opinions that only the lifting bodies based on the M2 shape were "true lifting bodies" so, there are other well informed folks who have had a more narrow view.

BTW- if you do not know who the two people I've cited here are- you would do well to find out before posting farther.

At the risk of dragging this even further OT, at various time BWB & Flying Wing aircraft have been called Lifting Bodies by their designers.  The term seems to have been flexibly used.  AIUI, just about any vehicle that uses the entirety of its' shape to generate lift while in atmospheric flight could be called a Lifting Body.

That said, I wouldn't care to argue the point with Eggers, Reed, Love, or Thompson.

Offline Rocket Science

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Just a reminder of a "one-stop shopping" for lifting body Q&A (arguments) ::) thread here... Play nice... ;D

http://forum.nasaspaceflight.com/index.php?topic=29126.0
« Last Edit: 08/19/2012 12:24 PM by Rocket Science »
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Offline vulture4

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I recognize that there are different opinions on the advantages of different aerodynamic entry vehicles. To my knowledge there has never been an actual engineering trade study directly comparing winged and wingless runway landing entry vehicles.

However having supported almost a hundred Shuttle landings, some very close to the margins, many others waved off because conditions were not ideal, it is not easy for me to understand why anyone would want to have less than the optimal lift and drag, and the minimal touchdown speed and the best possible final approach performance margins. If you don't think touchdown speed is important, the next time you get on an airliner ask the pilot if he'd like to land without flaps.

Wingless lifting bodies were first investigated because in the early 60's it was doubted that any material could be found that would tolerate the aerodynamic heating of a sharp leading edge. The Shuttle had wings because the necessary materials were developed and because, after over a decade of trying, there was no lifting body that could approach the performance of a winged vehicle. The Shuttle had better aerodynamic performance than any lifting body, even though they were boat-tailed and the Shuttle had huge engine bells that caused almost half its drag. With the tail cone installed the Shuttle has twice the L/D of the best wingless lifting body, an unimaginable difference in aviation, and that becomes particularly important as landing mass is increased. If you want more drag, you can always deploy a speed brake. If you want more lift (with the separated wing and tail of the X-37) you can lower the flaps. Just my opinion. Feel free to disagree.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070017478_2007014601.pdf
Here's the X-37; note low sink rate at touchdown in the third landing.
« Last Edit: 08/21/2012 02:15 AM by vulture4 »

Offline john smith 19

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However having supported almost a hundred Shuttle landings, some very close to the margins, many others waved off because conditions were not ideal,
Shuttle landings were unpowered. Due to them needing 5 mile visibility (because STS was not certified for instrument landing) and sitting on tires that were only rated to c 188knots landing speed if conditions were not *perfect* then reentry did not take place. Proposals as simple as changing some of the autopilot constants and logic could have fixed this.

Quote
Wingless lifting bodies were first investigated because in the early 60's it was doubted that any material could be found that would tolerate the aerodynamic heating of a sharp leading edge.
ACtually Reinfoced Carbon Carbon dates from around this time and was IIRC one of the options for the X20 Dyan Soar nose. For this kind of reentry it's not *peak* temperature given by rate of heat input (q dot) it's *total* heat input (Q) that was the problem.

Quote
The Shuttle had wings because the necessary materials were developed and because, after over a decade of trying, there was no lifting body that could approach the performance of a winged vehicle. The Shuttle had better aerodynamic performance than any lifting body, even though they were boat-tailed and the Shuttle had huge engine bells that caused almost half its drag. With the tail cone installed the Shuttle has twice the L/D of the best wingless lifting body, an unimaginable difference in aviation, and that becomes particularly important as landing mass is increased. If you want more drag, you can always deploy a speed brake. If you want more lift (with the separated wing and tail of the X-37) you can lower the flaps. Just my opinion. Feel free to disagree.
The *big* driver for wings was the USAF demand for return to launch site after 1 orbit. This required *huge* cross range, relative to a capsule design. IIRC the FDL5 lifting body design would have *global* cross range (Hypersonic L/D of something like 3.5) but would have made it a joint NASA/USAF programme (and I'm not sure if the FDL5 was still classified at that time).

BTW Orbiter wings are not "sharp" by conventional aircraft standards *relative* to the the size of the vehicle. AFAIK the shock front is still detached and in front of the leading edge.

The attractions of lifting bodies are the reduced acreage of TPS (The NASA TPS database lists replacement costs of tiles as $12000/m^2 nd blankets as $3000/m^2) and improved volumetric efficiency. You need a smaller planform and you can put stuff on top of most of the *area* of that plan form.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070017478_2007014601.pdf

A *very* nice paper. Interesting to see that what looks to be one of the design rules of thumb (Hoerners) is roughly 3x too small, which suggests some promising ideas that were evaluated with it (and failed) might have worked in IRL just fine, or vice versa (but got cancelled for other reasons before anyone tried to build them).

It's good to know people are still mining this data and not taking historic rules of thumb as gospel.

I hope designers of the *next* generation pay attention to the results.
[/quote]
[unit change mph to knots.Deleted YT link]
« Last Edit: 08/22/2012 07:34 AM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Jim

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Proposals as simple as changing some of the autopilot constants and logic could have fixed this.


Not true by any means. 

Offline john smith 19

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Proposals as simple as changing some of the autopilot constants and logic could have fixed this.


Not true by any means. 
On reading the report again
 " Evaluation of Potential Changes to the Space Shuttle Orbiter's Flight Control System to Increase Directional Control During Post Landing Rollout"

I realized I'd over simplified and conflated it with an AIAA report on how Shuttle lessons learned could assist a next generation vehicle. One of the key issues (in that report) was the Shuttle's inability to cope with any substantial cross winds.

With Shuttle gone the suggested solution to this is academic but the *issue* remains. DC's ability to land in cross winds is important if they don't want to have the same constraints on launch day weather (to handle aborts) as well as landing day weather that Shuttle had.

I hope DC will do better (shuttle weights evolved upward and it looked as if the landing gear and tire design did not keep up) but I guess that uncertainty was one of the other reasons the lifting body concept has never had a full scale workout.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline zerm

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Ok zerm took your advice and looked it up.

Here's a couple of good links I found. I didn't know who these guys were before so thanks for enlightening me.  ;D

http://www.nasa.gov/centers/dryden/news/NewsReleases/2005/05-13_prt.htm

http://www.nasa.gov/centers/dryden/news/Biographies/Pilots/bd-dfrc-p018.html

If you want to get into Lifting Bodies, both of their books are a must read as is "From Runway to Orbit" by Kenneth W. Hiff and Curtis L. Peebles.

I find that the conversation gets far more palatable when we have a greater scope of distinction of vehicles and shapes other than something on the level of; this one has things sticking out of it and that one does not. ;) Besides, the study of the history of lifting bodies serves to get you more excited about the rise of the former HL-20 shape into the SNC Dream Chaser.

Offline Wayne Hale

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The shuttle maximized lift from different parts of its anatomy at different phases of flight.  Hypersonic lift was largely developed by the fuselage, "lifting body".  Supersonic lift was generated more by the wings, which enhanced crossrange capability.  Crossrange capability is a good thing to allow for the maximum landing options.

The shuttle main gear tire ground speed limit was 225 kts; margin testing showed that there was some capability above that.  The real concern was the "critical speed" which was a combination of rotational speed and the maximum downward force exerted on the tires - this generally occurred during derotation after passing through negative angle of attack but before the nose gear touched.  Several flight software and operational changes helped the situation.

Most shuttle landing wave-offs for Florida were due to thunderstorms in the area (same is true for launch holds).  All aerospace vehicles are susceptable to lightning and the severe turbulence associated with thunderstorms.  This is true for capsules, winged vehicles, lifting bodies, etc.  Having the crossrange to redesignate to another runway can help, so can having loiter capability if you want to carry jet engines and jet fuel.

Online BrightLight

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Being that I don't know what the DC CDR requires, just for reference this is a set of definitions of a CDR

"Critical Design Review (CDR)

The CDR demonstrates that the maturity of the design is appropriate to support proceeding with full-scale fabrication, assembly, integration, and test. CDR determines that the technical effort is on track to complete the flight and ground system development and mission operations, meeting mission performance requirements within the identified cost and schedule constraints.[3]

The following are typical objectives of a CDR:

    Ensure that the "build-to" baseline contains detailed hardware and software specifications that can meet functional and performance requirements
    Ensure that the design has been satisfactorily audited by production, verification, operations, and other specialty engineering organizations
    Ensure that the production processes and controls are sufficient to proceed to the fabrication stage
    Establish that planned Quality Assurance (QA) activities will establish perceptive verification and screening processes for producing a quality product
    Verify that the final design fulfills the specifications established at PDR"

from wikipedia.

Offline yg1968

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This article on Orion's CDR in 2015 also explains what CDR is for a spacecraft such as Orion but it should also fit for DC:
http://www.nasaspaceflight.com/2012/01/eft-1-spring-2014-launch-date-contract-negotiations/

Quote
“The CDR is a critical DDT&E milestone, where the contractor discloses its complete spacecraft system design in full detail, identifying areas where technical problems and design anomalies have been resolved,” the document states.

“Successful completion of the CDR will validate that the contractor’s spacecraft design maturity is at an acceptable level that justifies the decision to initiate fabrication/manufacturing, integration and verification of the flight hardware and software.”

In any event, DC will almost get to CDR at the end of the CCiCap base period in 2014 but not quite. I hope that NASA will exercise the CCiCap optional milestones that will allow it to get to CDR prior to making any further down selection in 2014 or 2015. 
« Last Edit: 08/24/2012 05:01 PM by yg1968 »

Online BrightLight

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This article on Orion's CDR in 2015 also explains what CDR is for a spacecraft such as Orion but it should also fit for DC:
http://www.nasaspaceflight.com/2012/01/eft-1-spring-2014-launch-date-contract-negotiations/

Quote
“The CDR is a critical DDT&E milestone, where the contractor discloses its complete spacecraft system design in full detail, identifying areas where technical problems and design anomalies have been resolved,” the document states.

“Successful completion of the CDR will validate that the contractor’s spacecraft design maturity is at an acceptable level that justifies the decision to initiate fabrication/manufacturing, integration and verification of the flight hardware and software.”

In any event, DC will almost get to CDR at the end of the CCiCap base period in 2014 but not quite. I hope that NASA will exercise the CCiCap optional milestones that will allow it to get to CDR prior to making any further down selection in 2014 or 2015. 
This response and my post (#26) are consistent - good!
The milestones for DC CCiCap do not include CDR. Then, if an optional milestone is required for DC to perform the CDR, how much will it cost and what is the incremental work that needs to be performed to get there?
Being that I'm an optimist, I assume that there will be funds available for SNC to get the work done.

Offline yg1968

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The optional milestones have been redacted because they were considered to be propietary. So nobody knows for sure. Gerst only said that DC had optional milestones that could get them to CDR if they are exercised by NASA.

Online BrightLight

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The optional milestones have been redacted because they were considered to be propietary. So nobody knows for sure. Gerst only said that DC had optional milestones that could get them to CDR if they are exercised by NASA.
I saw the redaction too, SNC appears to have a good record of completing milestones on time, with some luck they will make there schedule and see the extra milestones added.

Offline john smith 19

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I saw the redaction too, SNC appears to have a good record of completing milestones on time, with some luck they will make there schedule and see the extra milestones added.
As always "funding permitting"

Which will need lobbying to ensure money is in the 2014 budget.

Perhaps a little note to your local members of the Legislature, along with Frank Wolf (R-VA) who came up with the 2.5 Awards scheme.

"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

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