SNC outline Dream Chaser's Enterprise-style landing test approach

[Chris Bergin]

http://www.nasaspaceflight.com/2012/06/snc-dream-chasers-enterprise-test-approach/

Really, really enjoying writing these up. Again thanks to Lee Jay for carrying out the interview for this latest series of content (full resources in L2).

Another article to come in this series.

[Lars_J]

Great article - I look forward to seeing this bird fly.

[Helodriver]

Has it been determined if the vertical stabilizer is movable?

[Zachstar]

Thanks for the article!

If I had to pick. I would consider this a STRONG #2 for crew to the ISS. Yet I very much worry of what will happen if they get reduced funding in the #3 slot. The lack of funding is already pushing manned flights back by years and I wonder if any of these smaller companies can seriously say "no worries we can wait" for a flight chance and funding after SpaceX and Boeing.

If that happens it ought to be made into a movie. Oldspace Spacecraft and systems astronomically overbudget while newer companies meeting EVERY objective on time despite reduced chances getting the boot because congress thinks 300M is better spent elsewhere. I would say that is surprising but this is congress we are talking about.

[Chris Bergin]

Great article - I look forward to seeing this bird fly.

Thanks!

And thread trimmed after being derailed into a complete unrelated BEO discussion.

[Prober]

Great article - I look forward to seeing this bird fly.

Yes, sounds like a well thought out test program.

"The test plan also progresses towards the use Dream Chaser’s hybrid motors, for the purpose of expanding the flight envelope both faster and higher, during the later stages of testing."

[Zachstar]

I agree. And as the motors are designed for very routine suborbital flights on the SS2 the cost to do it should be small compared to the extra data it gains.

That is why I think they are deserving of the #2 slot. Even tho most likely that spot will go to Boeing.

[BrightLight]

Great article Chris - Thanks for your hard work.
How long will the ALT test program last.
How fast will the DC go with its rockets
How high will she get.
looking forward to seeing the resurgence of dynamic test programs at Edwards again

[Lee Jay]

How long will the ALT test program last.
How fast will the DC go with its rockets
How high will she get.

I asked all those questions.  For the first, they weren't sure because it would depend on how things went, sort of like SpaceX and C2/C3/C2+.  For the second two, they weren't ready to share that information yet, but they did point out that the engines are quite powerful and so they could expand the envelope significantly compared to a free drop.

[Lurker Steve]

What exactly is the challenge with tires in space ?

I assume they aren't inflatable tires, but one solid piece of rubber-like material. I can understand the issues with handling a gas-filled tire in space. Too much expansion / contraction with the pressure changes.

Is the problem with a "steer-able" wheel, where the steering mechanism might freeze up , and that doesn't happen with the rear wheels that are only expected to roll in a fixed direction ?

[BrightLight]

How long will the ALT test program last.
How fast will the DC go with its rockets
How high will she get.

I asked all those questions.  For the first, they weren't sure because it would depend on how things went, sort of like SpaceX and C2/C3/C2+.  For the second two, they weren't ready to share that information yet, but they did point out that the engines are quite powerful and so they could expand the envelope significantly compared to a free drop.

Thanks Lee Jay. FWIW - you are a generous person, thanks again.

[FinalFrontier]

http://www.nasaspaceflight.com/2012/06/snc-dream-chasers-enterprise-test-approach/

Really, really enjoying writing these up. Again thanks to Lee Jay for carrying out the interview for this latest series of content (full resources in L2).

Another article to come in this series.

Thanks for the article Chris.

[BrightLight]

What exactly is the challenge with tires in space ?

I assume they aren't inflatable tires, but one solid piece of rubber-like material. I can understand the issues with handling a gas-filled tire in space. Too much expansion / contraction with the pressure changes.

Is the problem with a "steer-able" wheel, where the steering mechanism might freeze up , and that doesn't happen with the rear wheels that are only expected to roll in a fixed direction ?

I've been wondering this myself - I can see that a skid is more thermally benign, uses less volume stored, simple to replace. Are these real issues- the Shuttle, SR-71, xb-70 all had difficult thermal conditions up front bujt clearly were solved. Both the SR-71 and the Shuttle had early problems with tires/struts but this technology has been available for decades.

[Go4TLI]

What exactly is the challenge with tires in space ?

I assume they aren't inflatable tires, but one solid piece of rubber-like material. I can understand the issues with handling a gas-filled tire in space. Too much expansion / contraction with the pressure changes.

Is the problem with a "steer-able" wheel, where the steering mechanism might freeze up , and that doesn't happen with the rear wheels that are only expected to roll in a fixed direction ?

Given the thermal environment and ranges it sees the tire pressures have to monitored appropriately.  In addition, in order to keep the tires healthy this could be a driver from a thermal perspective.  And given this vehicle projected length of stay on orbit it is easier if one tire can be removed, especially when it is in a different zone of the vehicle.

[brihath]

Great article Chris! 

I would be interested in learning how close the DC flight test version is to the orbital version.  It looks like it doesn't have TPS installed, but what else is not installed that is required for the orbital version?  Perhaps that could be covered in a future article?

[Thorny]

The first X-37B spent longer than Dream Chaser will in space, and the second will be over twice as long in space. Is there any sharing of information about tires between the two projects?

[brihath]

What exactly is the challenge with tires in space ?

I assume they aren't inflatable tires, but one solid piece of rubber-like material. I can understand the issues with handling a gas-filled tire in space. Too much expansion / contraction with the pressure changes.

Is the problem with a "steer-able" wheel, where the steering mechanism might freeze up , and that doesn't happen with the rear wheels that are only expected to roll in a fixed direction ?

Given the thermal environment and ranges it sees the tire pressures have to monitored appropriately.  In addition, in order to keep the tires healthy this could be a driver from a thermal perspective.  And given this vehicle projected length of stay on orbit it is easier if one tire can be removed, especially when it is in a different zone of the vehicle.

I understand there may be a challenge there, but hasn't that already been tested in the X-37?  Does it have a nose skid or a tire?

[Go4TLI]

What exactly is the challenge with tires in space ?

I assume they aren't inflatable tires, but one solid piece of rubber-like material. I can understand the issues with handling a gas-filled tire in space. Too much expansion / contraction with the pressure changes.

Is the problem with a "steer-able" wheel, where the steering mechanism might freeze up , and that doesn't happen with the rear wheels that are only expected to roll in a fixed direction ?

Given the thermal environment and ranges it sees the tire pressures have to monitored appropriately.  In addition, in order to keep the tires healthy this could be a driver from a thermal perspective.  And given this vehicle projected length of stay on orbit it is easier if one tire can be removed, especially when it is in a different zone of the vehicle.

I understand there may be a challenge there, but hasn't that already been tested in the X-37?  Does it have a nose skid or a tire?

It definitely has tires for the mains, and maybe nose too.  However, that is a free flying vehicle and therefore the thermal constraints are much easier to manage

[Rocket Science]

From the history of flights from the series of lifting bodies a safe prediction will be the challenges in the flight control system. Fortunately with the power of modern computers and simulators will help ameliorate the situation...

[Chris Bergin]

Thanks guys! And yes, there's a lot more to cover. We have some of that already for the next article, but I need to speak to the good people at Aerojet (always very helpful) about the trusters to complete this next article.

[Lee Jay]

What exactly is the challenge with tires in space ?

I assume they aren't inflatable tires, but one solid piece of rubber-like material.

They are inflatable tires, and they have to endure change to a vacuum and a pretty wide thermal environment.

[arachnitect]

It's good that we're getting some quality reports on Dreamchaser; thanks Chris and Lee Jay.

Is White Knight II the only fixed wing mothership available? SCA is the only other option I can think of.

[Orbiter]

Interesting to see that Lindsey will be doing ALT tests, reminds me of how Haise did ALT tests for Shuttle.

Orbiter

[Lee Jay]

Thanks Lee Jay. FWIW - you are a generous person, thanks again.

Thanks, but any little bit that I can contribute is orders of magnitude less that I've received from the site from the site experts such as Jim and Jorge and Pete and Phillip and all the other regulars (you know who you are), not to mention Chris' remarkable expertise in turning volumes of L2 information into easy to understand bite-sized articles.

[tigerade]

Neat.  Looking forward to watching these tests. 

[Lee Jay]

It's good that we're getting some quality reports on Dreamchaser; thanks Chris and Lee Jay.

Is White Knight II the only fixed wing mothership available? SCA is the only other option I can think of.

They said there were other possibilities.  I'm not sure what they were referring to, but military planes such as the B-52 and even Orbital's L-1011 have carried and dropped aircraft or spacecraft.  Maybe they have something like that lined up?

[Lars_J]

The front tire on a DC would probably be more difficult than on the Shuttle, due to limited space between the pressurized composite structure and the outer thermal protection system. So there would be less of a thermal buffer, I would guess.

[Thorny]

Is White Knight II the only fixed wing mothership available? SCA is the only other option I can think of.

Orbital's L-1011?

[Downix]

Is White Knight II the only fixed wing mothership available? SCA is the only other option I can think of.

Orbital's L-1011?

Antonov An-225 comes to mind, strapped to the back.

[Lars_J]

It seems like the WKII or a B-52 are the only options for a simpler drop (compared to being carried on top). But it might be too much even for a B-52?

[Downix]

It seems like the WKII or a B-52 are the only options for a simpler drop (compared to being carried on top). But it might be too much even for a B-52?

Orbital's Stargazer also handles a similar drop:

[Lars_J]

DC is much bigger than a Pegasus XL. (vertically) There won't be enough ground clearance, unless I am mistaken. (see image below)

[TomH]

Regarding nose wheel steering, most ground steering (particularly during landing) on any aircraft is done by differential braking to starboard and port wheels.

[jnc]

Regarding nose wheel steering, most ground steering (particularly during landing) on any aircraft is done by differential braking to starboard and port wheels.

Yes, but the Shuttle had both differential braking and steerable nosewheels, and after 'issues' (a blowout) they started using the latter more. (More here.) Not sure if the causes for the Shuttle's issues would carryover to DC, though.

Noel

[Go4TLI]

Not sure if the causes for the Shuttle's issues would carryover to DC, though.

Noel

With respect to the orbiter it was a very large, and heavy spacecraft.  At the speed and angle the vehicle touched down the wheels would warm significant very quickly.  The brakes also input additional heat into the system that lasted for some time due to thermal soack-back.  Using the breaks more just adds more heat.

With DC this will also be an issue but the vehicle is smaller and lighter.  Like the orbiter and many larger aircraft, "keep-out zones" will certainly be established until this heat soackback has disipated and the tires are again a more normal temperature. 

[TomH]

Regarding nose wheel steering, most ground steering (particularly during landing) on any aircraft is done by differential braking to starboard and port wheels.

Yes, but the Shuttle had both differential braking and steerable nosewheels, and after 'issues' (a blowout) they started using the latter more. (More here.) Not sure if the causes for the Shuttle's issues would carryover to DC, though.

Noel

During a landing, both brakes are being applied for negative Delta V, and the difference in the amount of braking applied to the two sides in order to maintain center-line alignment is negligible. I would not expect there to be even 1% difference between the amount of friction applied to the port and starboard brakes for the purpose of maintaining center-line alignment; if cross-winds were that powerful, the mission would not be given a go for de-orbit burn prior to landing. It is a stretch for me to believe that use of port and starboard brakes to steer caused any problem on STS. In that the brakes are being applied mainly for the purpose of deceleration, I would think that brake heat or a tire defect would have more to do with it. I can see how the need to crab at a vectored angle in a cross-wind would cause a tire to burst if the wheels are rigidly fixed and not allowed to pivot and stay in alignment with the runway during the landing. That friction would chew a tire to pieces quickly and easily. A center-front wheel on something like DC would not need to be actively steerable from the stick, it would only need to be able to pivot on its own (to maintain alignment with the runway center-line) while the port/starboard brake differential did the steering.

The B-52 is a good example of an airplane on which the entire gang of wheels has to pivot. As a large and heavy high-wing plane (with no left and right wheels other than small outriggers-high wings dictate wheel gangs going fore and aft of bomb bay) that had to be able to take off and land in heavy cross-winds, the plane might be crabbed 10 degrees into the wind while the wheel gangs remained lined-up with the runway. If the wheels could not pivot, landing at a crabbed angle would chew them to pieces instantly.

[Rocket Science]

Lifting Body Air and Spacecraft Q & A

With all the interest generated by Dream Chaser and its direct ancestor the HL-20 and all the other lifting body vehicles, the thread linked below is to discuss, inform and exchange general questions, ideas and answers as to what exactly a Lifting Body is. This is to keep the Dream Chaser threads clean and without clutter and OT topics as things get busier now.

http://forum.nasaspaceflight.com/index.php?topic=29126.msg914401;topicseen#new

[Rocket Science]

Lifting Body Air and Spacecraft Q & A

With all the interest generated by Dream Chaser and its direct ancestor the HL-20 and all the other lifting body vehicles, I created this thread to discuss, inform and exchange general questions, ideas and answers as to what exactly a Lifting Body is. This is to keep the Dream Chaser threads clean and without clutter and OT topics as things get busier now.

http://forum.nasaspaceflight.com/index.php?topic=29126.msg914401;topicseen#new

O.K., you are not being clear enough in whatever you are trying to imply and what you want us to infer. You state here that the thread was "created to discuss...what exactly a lifting body is."  In the same sentence you include "...discuss, inform, and exchange general questions..."  The thread title clearly references "...landing test..."

Are you saying that brakes and steering are not part of landing? Are you saying that because you started the thread you feel the prerogative strictly to control the posts if they do not meet your definition of being on-topic or off-topic? Just asking, because I want to understand you with complete clarity before I respond further.

Hey Tom,

No much more basic than that: Only related to basic lifting bodies in general ie) aerodynamics.

You don't need my permission to discuss anything, for example DC brakes... Ultimately Chris has the Last say...

Regards
Robert

[TomH]

Lifting Body Air and Spacecraft Q & A

With all the interest generated by Dream Chaser and its direct ancestor the HL-20 and all the other lifting body vehicles, I created this thread to discuss, inform and exchange general questions, ideas and answers as to what exactly a Lifting Body is. This is to keep the Dream Chaser threads clean and without clutter and OT topics as things get busier now.

http://forum.nasaspaceflight.com/index.php?topic=29126.msg914401;topicseen#new

May I suggest you change this thread to say the thread linked below?  Chris created this thread and at first read it sounded like you were chastising us for posts we have made immediately above. I had figured out what you meant and deleted the post you quoted before you finished your reply.

[jnc]

It is a stretch for me to believe that use of port and starboard brakes to steer caused any problem on STS.

Hey, I'm just passing on what that NASA web site I linked to said - take it up with them.

Noel

[Rocket Science]

Lifting Body Air and Spacecraft Q & A

With all the interest generated by Dream Chaser and its direct ancestor the HL-20 and all the other lifting body vehicles, I created this thread to discuss, inform and exchange general questions, ideas and answers as to what exactly a Lifting Body is. This is to keep the Dream Chaser threads clean and without clutter and OT topics as things get busier now.

http://forum.nasaspaceflight.com/index.php?topic=29126.msg914401;topicseen#new

May I suggest you change this thread to say the thread linked below?  Chris created this thread and at first read it sounded like you were chastising us for posts we have made immediately above. I had figured out what you meant and deleted the post you quoted before you finished your reply.

Done, Thanks Tom!

[TomH]

It is a stretch for me to believe that use of port and starboard brakes to steer caused any problem on STS.

Hey, I'm just passing on what that NASA web site I linked to said - take it up with them.

Noel

Are you sure you read it all correctly and did you read and understand the entirity of my post above? I am not certain, but I wonder if the changes involved making the nose wheel able to free pivot or making it actively steerable from the stick. There is a huge difference. Taking a non-steerable wheel and making it steerable would involve a lot of hydraulic re-plumbing as well as add excessive weight, an ability and mass that are completely unnecessary. You posted it; I'm not "taking it up with you" so to speak, but rather discussing a concept that you introduced.

[spectre9]

I hope the landings are nice and smooth.

This is the ace Dream Chaser holds.

After long duration Mars simulations on orbit astronauts might need a comfortable touchdown and getting the right medical staff and other support crews to a remote locations / splashdown sites could prove costly in the long run.

I like that SNC works with Boeing, don't know exactly how. Something to do with the flight controls and simulator?

The stuff with the university students didn't go unnoticed either.

I think the good will that's been generated in such a short time really increases the chances of Dream Chaser becoming a reality.

Can't wait to see free flight and landing.

This is the big intangible draw card DC has. It will be a poster child. Something to put in the presentations and show to the public. Surely we've all heard the "capsules are boring" lines from those less enthused by the space program. Any support that NASA can get is worth going for.

[Lurker Steve]

It is a stretch for me to believe that use of port and starboard brakes to steer caused any problem on STS.

Hey, I'm just passing on what that NASA web site I linked to said - take it up with them.

Noel

Are you sure you read it all correctly and did you read and understand the entirity of my post above? I am not certain, but I wonder if the changes involved making the nose wheel able to free pivot or making it actively steerable from the stick. There is a huge difference. Taking a non-steerable wheel and making it steerable would involve a lot of hydraulic re-plumbing as well as add excessive weight, an ability and mass that are completely unnecessary. You posted it; I'm not "taking it up with you" so to speak, but rather discussing a concept that you introduced.

I read the NASA report, and it said the blow-out was in the main gear. I'm not sure why they would change the nose wheel when that's not where the problem occurred.

It sounds like the solution was thicker tires and a smoother runway surface. Add in the parachutes also.

How much speed did the shuttle have during landings ? I think the DreamChaser will actually come in a bit slower, right ? Less airspeed means less braking on the runway.

[jnc]

I wonder if the changes involved making the nose wheel able to free pivot or making it actively steerable from the stick. There is a huge difference.

From the NASA page:

"because the nose gear had only a single strain control system, shuttle pilots were reluctant to use it at all, preferring differential braking with the main landing gear instead to control the shuttle's rollout down the runway"

[Then, after the failure and subsequent investigations...]

"The nose wheel was given greater steering authority" (emphasis mine)

So, how would you interpret those statements?

Noel

[Jim]

It is a stretch for me to believe that use of port and starboard brakes to steer caused any problem on STS.

It doesn't matter what you believe, differential braking was part of the problems with the brake system, along with orbiter weight growth and axle flexing. 

Active nose wheel steering was added.

[Zachstar]

I hope the landings are nice and smooth.

This is the ace Dream Chaser holds.

After long duration Mars simulations on orbit astronauts might need a comfortable touchdown and getting the right medical staff and other support crews to a remote locations / splashdown sites could prove costly in the long run.

I like that SNC works with Boeing, don't know exactly how. Something to do with the flight controls and simulator?

The stuff with the university students didn't go unnoticed either.

I think the good will that's been generated in such a short time really increases the chances of Dream Chaser becoming a reality.

Can't wait to see free flight and landing.

This is the big intangible draw card DC has. It will be a poster child. Something to put in the presentations and show to the public. Surely we've all heard the "capsules are boring" lines from those less enthused by the space program. Any support that NASA can get is worth going for.

ANY ability to go outside ISS 6 month stays has no bearing on the selection process. That would at once cause one hell of an uproar. The contract is for crew flights to the ISS. That is it.

Edit2: What it really has as a trump card is how different it is from the SpaceX and from the capsule concept itself. Thus it becomes a very effective backup to SpaceX. Tho congress will balk at this because they think companies like SN are the next Solyndra waiting to happen. They will want old big bloated company involvement and Boeing fits this #2 perfectly.

[TomH]

I wonder if the changes involved making the nose wheel able to free pivot or making it actively steerable from the stick. There is a huge difference.

From the NASA page:

"because the nose gear had only a single strain control system, shuttle pilots were reluctant to use it at all, preferring differential braking with the main landing gear instead to control the shuttle's rollout down the runway"

[Then, after the failure and subsequent investigations...]

"The nose wheel was given greater steering authority" (emphasis mine)

So, how would you interpret those statements?

Noel

I'd say you interpreted it correctly. I have to wonder, however, if the initial design, in an attempt toward minimal mass, made the landing system not enough robust.

[BrightLight]

One of the advantages that SNC holds is that it is a very large contractor in the defense industry, and as such has deep resources to  use for development and manufacturing. The development and manufacturing of DC should be easily managed by SNC, they have the depth and breath to build sub systems internally and the management skills to run the contracts with Boeing etc. It appears from there first full scale flight test that they are rapidly running up the learning curve in flying and testing new airframes.  I hope they can make it thru to orbital tests.

[TomH]

It is a stretch for me to believe that use of port and starboard brakes to steer caused any problem on STS.

It doesn't matter what you believe, differential braking was part of the problems with the brake system, along with orbiter weight growth and axle flexing. 

Active nose wheel steering was added.

LOL, Thanks Jim.  What mass penalty was incurred? I presume the changes involved hydraulics, not fly by wire with electric motors?  It sounds like there were multiple factors involved. I would think DC has such a lighter mass than STS that the braking and steering systems could be considerably different. Obviously, a front skid is not going to have the steering agility of a steerable nose wheel.

[TomH]

This is the ace Dream Chaser holds.

After long duration Mars simulations on orbit astronauts might need a comfortable touchdown and getting the right medical staff and other support crews to a remote locations / splashdown sites could prove costly in the long run.

Wouldn't an actual Mars return likely hold the possibility of an even more difficult return? Fatigue, possible injuries sustained on the Martian surface. DC would not be available then, only Orion (possibly an advanced Dragon). AFAIK, DC's TPS cannot dissipate any heat greater than that generated by LEO return. I would think it better to practice long duration returns in the same craft that will actually be used on a real Mars return.

[jnc]

Active nose wheel steering was added.

Is that 'nose-wheel steering, previously not present, was added', or 'extra authority was added to that already present'? I ask because the more natural reading of that is the first, but that page I quoted (upthread) said a couple of things (e.g.  "nose wheel was given greater steering authority") which imply (to me) that there was some there to start with?

Noel

[Rocket Science]

Active nose wheel steering was added.

Is that 'nose-wheel steering, previously not present, was added', or 'extra authority was added to that already present'? I ask because the more natural reading of that is the first, but that page I quoted (upthread) said a couple of things (e.g.  "nose wheel was given greater steering authority") which imply (to me) that there was some there to start with?

Noel

We discussed this before, have a look...

http://forum.nasaspaceflight.com/index.php?topic=9921.msg878422#msg878422

[jnc]

We discussed this before, have a look...

Hmmm - the NASA page that discussion links to (here) seems initially to contradict the other page on this point - and then winds up potentially contradicting itself!

"until nose wheel steering and improved brakes were installed" (implying it didn't have NWS before)

and then:

"The space planes have been outfitted with ... additional nose wheel steering capability."

Now, whether to read that latter as 'there was some there before and we added to it' (which is how one would normally read that, I think) or 'we added an additional capability' - who knows?

What troubles me is that the other NASA page said that before the blowout, "because the nose gear had only a single strain control system, shuttle pilots were reluctant to use it at all, preferring differential braking .. to control the shuttle's rollout down the runway", that did seem to imply pretty forcefully that they had a choice of two systems, and preferred the differential braking - so what was the other choice, then, if not NWS?

I'm just going to throw up my hands at this point!

Noel

[zerm]

Regarding nose wheel steering, most ground steering (particularly during landing) on any aircraft is done by differential braking to starboard and port wheels.

The above statement is completely incorrect. On aircraft with weights below 12,500 ground steering is done by way of breaks- but only at low speeds. On aircraft over 12,500 a tiller is used to rotate the nose wheel for steering. "During landing" ALL aircraft use aerodynamic surfaces until dropping below an airspeed directed by the aircraft's manual. Once reaching such a speed aircraft below 12,500# will use breaking to steer, aircraft over 12,500 will use the tiller. Although large aircraft (over 12,500#) have the ability to use differential braking, it is not normally done as it can cause problems in the breaking system, it's not fun for the passengers, provides wear and tare and is less precise than using the tiller.

I'm an ATP, Captain under FAR 121 and have flown both light and heavy aircraft of many sorts from airliners to corporate jets to bug smashers over the past 35 years. Plus I have a  Degree in Aeronautical Science. Thus, you all can take what I say here FWIW.

[spectre9]

This is the ace Dream Chaser holds.

After long duration Mars simulations on orbit astronauts might need a comfortable touchdown and getting the right medical staff and other support crews to a remote locations / splashdown sites could prove costly in the long run.

Wouldn't an actual Mars return likely hold the possibility of an even more difficult return? Fatigue, possible injuries sustained on the Martian surface. DC would not be available then, only Orion (possibly an advanced Dragon). AFAIK, DC's TPS cannot dissipate any heat greater than that generated by LEO return. I would think it better to practice long duration returns in the same craft that will actually be used on a real Mars return.

It would be good to be able to examine those that have had a 500 day in space before subjecting those astronauts to the high g loads of a BEO reentry. Possibly by throwing these people into ground based experiments to see if they would've handled a full Orion landing in their weakened state.

I know it isn't part of the currrent ISS mission but that might be a problem. The ISS mission has not been clearly defined here. As it currently is there will only be small crews on 6 month rotation and NOT PAST 2020. I'm sure this will change especially with international partners calling for greater ISS utilisation working towards exploration of deep space.

[Zachstar]

That has nothing to do with the Dream Chaser. Can we focus on the topic at hand?

[spectre9]

Is the mission for Dream Chaser in any way not tied into the ISS?

Off topic to discuss it's one and only destination? C'mon mate, leave it to the mods.

If the soft landings provided by DC can't be applied to the ISS mission that feature can't be used as an advantage over the competition.

This needs to be defined.

[Zachstar]

It can't be used as an advantage because that is not part of the selection process. The extra time it can stay in orbit as with the others is good in case of urgent need to hold off return. Its method of return is relevant because NASA wants options for return. (Water, Land, Crossrange, Emergency Options)

"Soft Landings" are not part of it. And anyone using any craft has to be able to withstand a hard landing anyway in case of survivable failure. It would be completely unethical otherwise.

[A_M_Swallow]

Is the mission for Dream Chaser in any way not tied into the ISS?

Off topic to discuss it's one and only destination? C'mon mate, leave it to the mods.

If the soft landings provided by DC can't be applied to the ISS mission that feature can't be used as an advantage over the competition.

This needs to be defined.

The Dream Chaser may be able to fly to a Bigelow spacestation as well as the ISS.  Although Mr Bigelow may want it to take off on both Atlas V and Falcon 9 launch vehicles.

To go to an EML-1/2 spacestation the Dream Chaser would need a kicker/upper stage with a delta-V of 3.77 km/s.  Unless the thermal protection system has been upgraded then the upper stage will need an addition delta-V of 3.77 km/s to bring the spacecraft back to LEO.

I am assuming that the Dream Chaser can carry sufficient food, water and ECLSS for the return journey.

[Jason1701]

Is the mission for Dream Chaser in any way not tied into the ISS?

Off topic to discuss it's one and only destination? C'mon mate, leave it to the mods.

If the soft landings provided by DC can't be applied to the ISS mission that feature can't be used as an advantage over the competition.

This needs to be defined.

The Dream Chaser may be able to fly to a Bigelow spacestation as well as the ISS.  Although Mr Bigelow may want it to take off on both Atlas V and Falcon 9 launch vehicles.

To go to an EML-1/2 spacestation the Dream Chaser would need a kicker/upper stage with a delta-V of 3.77 km/s.  Unless the thermal protection system has been upgraded then the upper stage will need an addition delta-V of 3.77 km/s to bring the spacecraft back to LEO.

I am assuming that the Dream Chaser can carry sufficient food, water and ECLSS for the return journey.

DC will not be flying BEO. An extra 3.77 km/s is unbearable.

[A_M_Swallow]

DC will not be flying BEO. An extra 3.77 km/s is unbearable.

You may have used the wrong word there.  3.77 km/s is bearable in the Orion or Dragon but not in the Dream Chaser(?).

p.s. I was planning on using thrust to return to LEO so the heat shield would only get a similar amount of heat.  Unfortunately the inspace stage will need enormous propellant tanks (2 * 3.77 = 7.54 km/s)

[Robotbeat]

DC will not be flying BEO. An extra 3.77 km/s is unbearable.

You may have used the wrong word there.  3.77 km/s is bearable in the Orion or Dragon but not in the Dream Chaser(?).

Exactly right. It has to do with TPS constraints, partly. Ablative can handle (at the extreme end, like the Galileo probe and nuclear warheads penetrating deep in the atmosphere at hypersonic velocities) almost arbitrary reentry heat loads, while tiles like the Shuttle or Dream Chaser use are only suitable for certain heat loads. The Shuttle/DreamChaser/X37B has to fly a very precise high-lifting reentry corridor or the TPS will fail.

[A_M_Swallow]

DC will not be flying BEO. An extra 3.77 km/s is unbearable.

You may have used the wrong word there.  3.77 km/s is bearable in the Orion or Dragon but not in the Dream Chaser(?).

Exactly right. It has to do with TPS constraints, partly. Ablative can handle (at the extreme end, like the Galileo probe and nuclear warheads penetrating deep in the atmosphere at hypersonic velocities) almost arbitrary reentry heat loads, while tiles like the Shuttle or Dream Chaser use are only suitable for certain heat loads. The Shuttle/DreamChaser/X37B has to fly a very precise high-lifting reentry corridor or the TPS will fail.

Reread what I wrote.  I had prepared for that.  The tiles only get a LEO heat load.

[Jason1701]

DC will not be flying BEO. An extra 3.77 km/s is unbearable.

You may have used the wrong word there.  3.77 km/s is bearable in the Orion or Dragon but not in the Dream Chaser(?).

p.s. I was planning on using thrust to return to LEO so the heat shield would only get a similar amount of heat.  Unfortunately the inspace stage will need enormous propellant tanks (2 * 3.77 = 7.54 km/s)

I meant that the 3.77 km/s to return to LEO is an unbearable addition to the delta-v budget. As you said, it would mean DC would be like a SSTO. Returning to LEO propulsively just so you can reenter is goofy.

[Go4TLI]

DC will not be flying BEO. An extra 3.77 km/s is unbearable.

You may have used the wrong word there.  3.77 km/s is bearable in the Orion or Dragon but not in the Dream Chaser(?).

p.s. I was planning on using thrust to return to LEO so the heat shield would only get a similar amount of heat.  Unfortunately the inspace stage will need enormous propellant tanks (2 * 3.77 = 7.54 km/s)

I meant that the 3.77 km/s to return to LEO is an unbearable addition to the delta-v budget. As you said, it would mean DC would be like a SSTO. Returning to LEO propulsively just so you can reenter is goofy.

Not everything has to go to both LEO and beyond LEO.

[Jason1701]

DC will not be flying BEO. An extra 3.77 km/s is unbearable.

You may have used the wrong word there.  3.77 km/s is bearable in the Orion or Dragon but not in the Dream Chaser(?).

p.s. I was planning on using thrust to return to LEO so the heat shield would only get a similar amount of heat.  Unfortunately the inspace stage will need enormous propellant tanks (2 * 3.77 = 7.54 km/s)

I meant that the 3.77 km/s to return to LEO is an unbearable addition to the delta-v budget. As you said, it would mean DC would be like a SSTO. Returning to LEO propulsively just so you can reenter is goofy.

Not everything has to go to both LEO and beyond LEO.

We agree. And Dream Chaser should clearly just to go LEO, rather than become a SSTO to go beyond.

[Go4TLI]

We agree. And Dream Chaser should clearly just to go LEO, rather than become a SSTO to go beyond.

DC was never a Single Stage To Orbit vehicle. 

[Rocket Science]

What is going to interest me is the powered phase of the flight tests and how DC behaves going supersonic and potentially hypersonic if that is the plan. The associated trim changes for various portions of the flight envelope and the different control configurations as required. It’s going to be a nice follow-on to the X-planes decades ago….

[Jason1701]

We agree. And Dream Chaser should clearly just to go LEO, rather than become a SSTO to go beyond.

DC was never a Single Stage To Orbit vehicle. 

But it would need the mass ratio of one to fulfill Swallow's propulsive-braking-to-LEO idea.

[A_M_Swallow]

We agree. And Dream Chaser should clearly just to go LEO, rather than become a SSTO to go beyond.

DC was never a Single Stage To Orbit vehicle. 

But it would need the mass ratio of one to fulfill Swallow's propulsive-braking-to-LEO idea.

There is a significant difference.  SSTO have a delta-V of 9.3 -10 km/s.
The inspace stage(s) would need a delta-v of ~7.54 km/s.

[simonbp]

Not to dredge up Star Clipper again, but a slightly larger DC-derived vehicle with LH2/LOX drop tanks and two or three SSMEs on the back would make a very nice stage-and-a-half vehicle.

But gotta get the simpler one working first!

[strangequark]

There is a significant difference.  SSTO have a delta-V of 9.3 -10 km/s.
The inspace stage(s) would need a delta-v of ~7.54 km/s.

Still a lot of delta-V. Facts are:

DreamChaser cannot perform direct reentry from Lunar/EML-2
Propulsive deorbit is not a reasonable solution
Therefore, DreamChaser will not fly BEO

However, ISS is the only guaranteed destination for the foreseeable future, and none of the commercial vehicles will be going BEO anyway without modification.

[BrightLight]

These debates are starting to sound like what I do for a living -
maybe a separate thread should be built something like
"Commercial Applications to BEO CONOPS"

[baldusi]

There is a significant difference.  SSTO have a delta-V of 9.3 -10 km/s.
The inspace stage(s) would need a delta-v of ~7.54 km/s.

Still a lot of delta-V. Facts are:

DreamChaser cannot perform direct reentry from Lunar/EML-2
Propulsive deorbit is not a reasonable solution
Therefore, DreamChaser will not fly BEO

However, ISS is the only guaranteed destination for the foreseeable future, and none of the commercial vehicles will be going BEO anyway without modification.

Technically, if you developed a nice LEO to HEO SEP tug, you could try to take it somewhere like EML2. It might be ridiculous, specially for crew, due to the delta-t. But it could be possible

[Chandonn]

Can we get back on topic please?


I am unaware of approach and landing tests in BEO...

[Rocket Science]

Yes and they are going to occur on our Mars Flight Test Range… 

Come on guys, use the Q & A thread…

[Rocket Science]

I saw this neat local article on Dream Chaser with a unique photo angle and getting some personal loving care.

http://www.coloradohometownweekly.com/news/louisville/ci_20779285/big-week-commercial-space-flight-big-week-louisville

[vulture4]

What exactly is the challenge with tires in space ?

I assume they aren't inflatable tires, but one solid piece of rubber-like material. I can understand the issues with handling a gas-filled tire in space. Too much expansion / contraction with the pressure changes.

I had a chance to spend some time with one of the Shuttle tire engineers. They felt the environment for the tires in space was fairly benign. They were inflated with nitrogen at 315psi, a somewhat higher pressure than used on a airliner, but they were essentially normal 737-type aircraft tires and cost only about $5K apiece, which was minimal for Shuttle hardware. The temperature range in orbit was not excessive for tires.

[Go4TLI]

What exactly is the challenge with tires in space ?

I assume they aren't inflatable tires, but one solid piece of rubber-like material. I can understand the issues with handling a gas-filled tire in space. Too much expansion / contraction with the pressure changes.

I had a chance to spend some time with one of the Shuttle tire engineers. They felt the environment for the tires in space was fairly benign. They were inflated with nitrogen at 315psi, a somewhat higher pressure than used on a airliner, but they were essentially normal 737-type aircraft tires and cost only about $5K apiece, which was minimal for Shuttle hardware. The temperature range in orbit was not excessive for tires.

This is not entirely accurate.  Tires are an item that must be managed in space.  Not only will they slowly leak over time (just as the tires on your vehicle do) but the thermal environments must be managed to the point that the pressures do not climb to high or drop too low.

This is much easier to accomplish with a free-flying vehicle than it is with a vehicle docked to a station where now there very well can be (and are) competing systems for various environments and working the issues as an integrated stack. 

The removal of the nose gear tire from DC allowed them to remove one of those variables from the equation and still meet their control requirements.  It was a smart move on their part, especially given the vehicle could remain docked to ISS for months at a time. 

As for the "minimal" remark, that is not entirely accurate either and with many components in this business you will see prices across the board based on complexity, their uniqueness or if it is a COTS item and how many will be procured.

[clongton]

This is space, not aircraft. Don't need inflated tires.
Time to think about a paradigm change - wire spring tires.

[Jason1701]

What about solid rubber-like tires?

[clongton]

What about solid rubber-like tires?

Too heavy.

[Jim]

This is space, not aircraft. Don't need inflated tires.
Time to think about a paradigm change - wire spring tires.

No, this part is very much aircraft.

It is not the moon.

Can't take the spinup and scuffing from landing.

[Lee Jay]

What exactly is the challenge with tires in space ?

I assume they aren't inflatable tires, but one solid piece of rubber-like material. I can understand the issues with handling a gas-filled tire in space. Too much expansion / contraction with the pressure changes.

I had a chance to spend some time with one of the Shuttle tire engineers. They felt the environment for the tires in space was fairly benign. They were inflated with nitrogen at 315psi, a somewhat higher pressure than used on a airliner, but they were essentially normal 737-type aircraft tires and cost only about $5K apiece, which was minimal for Shuttle hardware. The temperature range in orbit was not excessive for tires.

This is not entirely accurate.  Tires are an item that must be managed in space.  Not only will they slowly leak over time (just as the tires on your vehicle do) but the thermal environments must be managed to the point that the pressures do not climb to high or drop too low.

This is much easier to accomplish with a free-flying vehicle than it is with a vehicle docked to a station where now there very well can be (and are) competing systems for various environments and working the issues as an integrated stack. 

Don't forget also that this vehicle is designed for 210 docked days - a heck of a lot longer than Shuttle.

[Go4TLI]

This is space, not aircraft. Don't need inflated tires.
Time to think about a paradigm change - wire spring tires.

No, this part is very much aircraft.

It is not the moon.

Can't take the spinup and scuffing from landing.

Likely even more basic than that.  These type tires would not be able to handle the weight in a 1 g field, not to mention the slap down loads, without being some significantly stiff mesh.

[Go4TLI]

Don't forget also that this vehicle is designed for 210 docked days - a heck of a lot longer than Shuttle.

Actually, I did mention that. 

[Prober]

This is space, not aircraft. Don't need inflated tires.
Time to think about a paradigm change - wire spring tires.

Michelin has a tire like this that could work.   Was designed to replace 4 auto tires.  Recall it worked but had sound issues, something a landing might not have an issue with.

[Rocket Science]

Shuttle’s nose gear tires might be correctly sized for DC’s main gear and are already space qualified. Perhaps stocks are still available…

[clongton]

Can't take the spinup and scuffing from landing.

Simple. Armature built into the hub. Just before touchdown, spin it up to landing speed. Automatically initiated by ground proximity.

Thinking outside the box.

[Ronsmytheiii]

Can't take the spinup and scuffing from landing.

Simple. Armature built into the hub. Just before touchdown, spin it up to landing speed. Automatically initiated by ground proximity.

Thinking outside the box.

KISS = regular tires and nose skid, just as SNC has done. No fancy, custom solution that adds on to cost and complexity needed.

Edit : Spaceshipone used same config.

[Jim]

Can't take the spinup and scuffing from landing.

Simple. Armature built into the hub. Just before touchdown, spin it up to landing speed. Automatically initiated by ground proximity.

Thinking outside the box.

You think wings are useless in space? 

[Lars_J]

Shuttle’s nose gear tires might be correctly sized for DC’s main gear and are already space qualified. Perhaps stocks are still available…

Yes but DC is supposed to stay in space for 10x longer than Shuttle - can the Shuttle nose gear handle that? (references for or against would be welcome)

[Rocket Science]

Shuttle’s nose gear tires might be correctly sized for DC’s main gear and are already space qualified. Perhaps stocks are still available…

Yes but DC is supposed to stay in space for 10x longer than Shuttle - can the Shuttle nose gear handle that? (references for or against would be welcome)

Hey Lars,
The only file I have on the nose gear tires is this one...
In terms of the long duration stays we, have the X-37 data set if not classifed. Tires seemed to perform fine upon landing as far as we know...

~Robert

Edit to add: There are a couple options of new technology for automotive such as run-flat and non-pneumatic tires for extreme use such as bullet proof and military applications (ie. honeycomb). None of these are for aviation or space applications AFAIK. Perhaps in the future these technologies can be incorporated but for now they would be costly to develop for SNC in such a small quantity. If off the shelf works, “why reinvent the wheel” for now…  Pun intended…

[clongton]

Can't take the spinup and scuffing from landing.

Simple. Armature built into the hub. Just before touchdown, spin it up to landing speed. Automatically initiated by ground proximity.

Thinking outside the box.

You think wings are useless in space? 

I do.

[Lurker Steve]

Can't take the spinup and scuffing from landing.

Simple. Armature built into the hub. Just before touchdown, spin it up to landing speed. Automatically initiated by ground proximity.

Thinking outside the box.

You think wings are useless in space? 

I do.

But, eventually the space craft enters the atmosphere, and those wings have a purpose again.

Even a capsule's heatshield is useless in space, but you have to carry some extra weight around if you plan on re-entry.

[clongton]

You think wings are useless in space? 

I do.

But, eventually the space craft enters the atmosphere, and those wings have a purpose again.

Even a capsule's heatshield is useless in space, but you have to carry some extra weight around if you plan on re-entry.

The question was not "are wings useless". It was are wings useless "in space". Wings serve no function "in space", thus are useless "in space".

[Prober]

Can't take the spinup and scuffing from landing.

Simple. Armature built into the hub. Just before touchdown, spin it up to landing speed. Automatically initiated by ground proximity.

Thinking outside the box.

KISS = regular tires and nose skid, just as SNC has done. No fancy, custom solution that adds on to cost and complexity needed.

Edit : Spaceshipone used same config.

round two they could look at something like this.....

[Rocket Science]

Yup, thems the ones...

[clongton]

Thank you. That's the ad I was looking for.

[Lobo]

Can't take the spinup and scuffing from landing.

Simple. Armature built into the hub. Just before touchdown, spin it up to landing speed. Automatically initiated by ground proximity.

Thinking outside the box.

You think wings are useless in space? 

I do.

They are useful for catching orbital debris and micrometeors on the TPS.

;-)

[Rocket Science]

Can't take the spinup and scuffing from landing.

Simple. Armature built into the hub. Just before touchdown, spin it up to landing speed. Automatically initiated by ground proximity.

Thinking outside the box.

You think wings are useless in space? 

I do.

They are useful for catching orbital debris and micrometeors on the TPS.

;-)

Catching dreams...

[vulture4]

The environment for the Shuttle tires (conventional aircraft tires inflated with nitrogen) was considered fairly benign. The X-37 uses smaller but otherwise similar tires with 300psi inflation pressure. It had one tire blowout on the first landing but otherwise no problems.

Regarding wings, I realize people have their preferences and aerodynamics may not generate a lot of interest. But the X-37 wings provide a much higher lift to drag ratio than the Dreamchaser's wingless lifting body shape and because it depends much less on body lift the X-37 can utilize a more efficient fuselage shape, with more internal volume, less structural mass, and less internal stress when pressurized. In fact this is why after decades of work with lifting bodies NASA decided to use wings for the Shuttle.

However I think the X-37 has a significant advantage over either the DC or Shuttle because of the long moment arm between its V-tail surfaces and the center of pressure, giving it greater tolerance for CG location (always a concern with the Shuttle) and much better pitch control when landing in variable or suboptimal winds, which often present themselves.

The question of wings vs parachute for landing is not a matter of mass, but of cost. A winged vehicle is easier to make fully reusable because there is no need for portions of the vehicle to be dropped (i.e. the heatshield for the CST) or deployed and refurbished, like the parachutes. The actual energy (i.e. fuel) to lift the wings into space costs almost nothing, and the X-37 of course had no foam fragments to damage its thermal tiles.

For a given booster lift capacity, a capsule will have more payload mass and volume than a runway lander, so as long as the booster is thrown away the capsule will have a cost or payload advantage. But if and when fully reusable boosters are available the initial booster cost will have little impact and one can simply choose a slightly larger booster. The easier reuse of the runway lander will then be a significant advantage.

[baldusi]

Err... lifting bodies have more internal volume, they are "fatter". The Shuttle had wings because of cross range consideration. Read the history of the discussions.

[Rocket Science]

Err... lifting bodies have more internal volume, they are "fatter". The Shuttle had wings because of cross range consideration. Read the history of the discussions.

He doesn’t get it... He keeps repeating the same things over and over again on all the Dream Chaser and X-37 threads...

[FinalFrontier]

The environment for the Shuttle tires (conventional aircraft tires inflated with nitrogen) was considered fairly benign. The X-37 uses smaller but otherwise similar tires with 300psi inflation pressure. It had one tire blowout on the first landing but otherwise no problems.

Regarding wings, I realize people have their preferences and aerodynamics may not generate a lot of interest. But the X-37 wings provide a much higher lift to drag ratio than the Dreamchaser's wingless lifting body shape and because it depends much less on body lift the X-37 can utilize a more efficient fuselage shape, with more internal volume, less structural mass, and less internal stress when pressurized. In fact this is why after decades of work with lifting bodies NASA decided to use wings for the Shuttle.

However I think the X-37 has a significant advantage over either the DC or Shuttle because of the long moment arm between its V-tail surfaces and the center of pressure, giving it greater tolerance for CG location (always a concern with the Shuttle) and much better pitch control when landing in variable or suboptimal winds, which often present themselves.

The question of wings vs parachute for landing is not a matter of mass, but of cost. A winged vehicle is easier to make fully reusable because there is no need for portions of the vehicle to be dropped (i.e. the heatshield for the CST) or deployed and refurbished, like the parachutes. The actual energy (i.e. fuel) to lift the wings into space costs almost nothing, and the X-37 of course had no foam fragments to damage its thermal tiles.

For a given booster lift capacity, a capsule will have more payload mass and volume than a runway lander, so as long as the booster is thrown away the capsule will have a cost or payload advantage. But if and when fully reusable boosters are available the initial booster cost will have little impact and one can simply choose a slightly larger booster. The easier reuse of the runway lander will then be a significant advantage.

All wrong.

[daveklingler]

The environment for the Shuttle tires (conventional aircraft tires inflated with nitrogen) was considered fairly benign.

Are you sure?  I seem to remember that a fair amount of engineering was devoted to the tires.  They had to endure extra heat, vacuum, and a high-speed landing.  Ditto with the gear.  We may be saying the same thing, i.e. you might mean "relatively benign", but I seem to remember that the problem of tires for a winged space vehicle is nontrivial.

Regarding wings, I realize people have their preferences and aerodynamics may not generate a lot of interest. But the X-37 wings provide a much higher lift to drag ratio than the Dreamchaser's wingless lifting body shape

A little higher, anyway, 4.5 versus 4. And here you'll note that DC uses a smaller fairing.  Increase the fairing size and nudge the vehicle size up a little bit and you could increase L/D by quite a bit pretty cheaply, if you thought it was necessary.

and because it depends much less on body lift the X-37 can utilize a more efficient fuselage shape, with more internal volume, less structural mass, and less internal stress when pressurized.

Actually, it's the other way around.  Part of the advantage of a lifting body is that the flying bathtub can generate lift while providing more internal volume and less structural mass.  Internal stress is equal, or maybe I'm not understanding what you mean by internal stress.

In fact this is why after decades of work with lifting bodies NASA decided to use wings for the Shuttle.

Dale Reed's opinion was that when push came to shove winged designs were always chosen because they had been chosen before, i.e. they were well inside the comfort zone.

However I think the X-37 has a significant advantage over either the DC or Shuttle because of the long moment arm between its V-tail surfaces and the center of pressure, giving it greater tolerance for CG location (always a concern with the Shuttle) and much better pitch control when landing in variable or suboptimal winds, which often present themselves.

I could be wrong, but I thought about this after I read it and decided that pitch control between the two vehicles was probably about equal or maybe in DC's favor.  Yaw control was more of an issue with early lifting bodies, but that's why DC has a center fin.  DC's pitch stability is better due to the high fin dihedral.

The question of wings vs parachute for landing is not a matter of mass, but of cost.

Wings versus parafoil is absolutely a matter of mass.  A large portion of an aircraft's mass lies in the wings, especially one that's supersonic (or hypersonic).  The main spar is quite heavy, and the control mechanisms aren't light either. The gear gets heavy when the high-speed landing is figured in, and the main spar gets heavier with the heavy gear.  If the wing is wet, not the case here, the spar gets even more massive, not to mention the weight of the tanks.  The X-38's parafoil was very much a way to achieve a lower stall with less mass.

Max Hunter's observation was that the wings were such a major portion of a spacecraft's weight that by leaving the wings off, one could carry so much extra propellant that vertical landing was possible.

A winged vehicle is easier to make fully reusable because there is no need for portions of the vehicle to be dropped (i.e. the heatshield for the CST) or deployed and refurbished, like the parachutes.

Here again that's the opposite of what's true.  A single center of forward pressure is far simpler to protect than a collection of leading edges and a belly, along with the gear and tires.  That's why capsules really are easier.

The actual energy (i.e. fuel) to lift the wings into space costs almost nothing, and the X-37 of course had no foam fragments to damage its thermal tiles.

IIRC Hunter told me the mass of the wings can sometimes approach close to 50%.  I've never done a weight trade on a spacecraft, so my opinion isn't informed, but I trust his.

For a given booster lift capacity, a capsule will have more payload mass and volume than a runway lander, so as long as the booster is thrown away the capsule will have a cost or payload advantage. But if and when fully reusable boosters are available the initial booster cost will have little impact and one can simply choose a slightly larger booster. The easier reuse of the runway lander will then be a significant advantage.

And here's where you get into an argument with the VTVL folks, who will tell you just the opposite.  If cross range is desirable, it's a different story.

[Lobo]

Wings versus parafoil is absolutely a matter of mass.  A large portion of an aircraft's mass lies in the wings, especially one that's supersonic (or hypersonic).  The main spar is quite heavy, and the control mechanisms aren't light either. The gear gets heavy when the high-speed landing is figured in, and the main spar gets heavier with the heavy gear.  If the wing is wet, not the case here, the spar gets even more massive, not to mention the weight of the tanks.  The X-38's parafoil was very much a way to achieve a lower stall with less mass.

Max Hunter's observation was that the wings were such a major portion of a spacecraft's weight that by leaving the wings off, one could carry so much extra propellant that vertical landing was possible.

A winged vehicle is easier to make fully reusable because there is no need for portions of the vehicle to be dropped (i.e. the heatshield for the CST) or deployed and refurbished, like the parachutes.

Here again that's the opposite of what's true.  A single center of forward pressure is far simpler to protect than a collection of leading edges and a belly, along with the gear and tires.  That's why capsules really are easier.

 

I’ve always liked the parafoil concept.  X-38 seemed to do pretty good with it.   Although, the thing is, with a parafoil, then you really don’t need the lifting body design.  Something like a Gemini capsule with deployable skids should be able to land just fine on a dry lake bed (or maybe a runway), and the capsule can be “flown” in a glide with the parafoil.  Using skids means you don’t need to mess with tires.  And then you can keep the heat shield protected while in orbit (which would have been particularly advantageous for a an Emergency Crew Return Vehicle that would be on the ISS for long periods of time until needed. 
Such a capsule landing horizontally with a parafoil could really be about as reusable as a spaceplane or lifting body.  Especially with a heat shield designed for say 10 reentries (like I think the Pica-X Dragon is?).  Even a reusable space plane needs a lot of TPS work between flights as we saw with the Shuttle, and I’m sure will be the case (although a lesser extent) with Dream Chaser. 
But it gets better efficiency without the wings and control surfaces and large TPS in mass and volume.  The landing skids could actually be such that the bottoms of them are flush with the sidewall of the capsule when retracted, so that they don’t actually need hatches/doors to open to deploy them.  And they could perhaps be spring loaded rather than electric or hydraulic so that they would be pretty reliable.   
The parafoil would need to be rechecked and maybe repaired and sometimes replaced, but I think that would be a pretty minor cost.  They aren’t landing in the ocean like the SRB, Apollo, or Orion chutes.
I think they had a good idea when they designed it for Gemini.  As I understand, the only reason it actually wasn’t implemented, is NASA had made the decision that Gemini wouldn’t continue during Apollo, which had originally been the plan.  Gemini would be a LEO taxi basically.  And would land using a parasail on a dry lake bed, and I think be reusable.  When the decision was made to cancel Gemini and not operate it during Apollo, they didn’t see the need to finish the horizontal landing development.  And in fact, since water recovery would be used for Apollo, it made more sense to keep with that, as it would be better practice for Apollo.  (hopefully I’m remembering that correctly anyway…).

[Rocket Science]

Gemini had a Rogallo wing parasail (parafoil) but also a high sink rate…

http://amyshirateitel.com/2011/05/22/losing-rogallo-from-gemini/