X-37C: plans for a crewed version of the X-37

[yg1968]

The plans for a crewed X-37C probably deserves a new dedicated thread.

See this article for details on the plans for a crewed X-37C:
http://www.space.com/13230-secretive-37b-space-plane-future-astronauts.html

See also these threads for previous discussions on this topic:
http://forum.nasaspaceflight.com/index.php?topic=23477.0
http://forum.nasaspaceflight.com/index.php?topic=13914.0

[docmordrid]

Aviation Week article.....

Very interesting that the military is thinking of crewed spaceflights.

[Danderman]

from the AvWeek story:

"The X-37B evolution study, which harks back to the pre-military NASA origins of the OTV, envisages a three-phase buildup. The first would see the current 29-ft.-long vehicle used for demonstration flights to the ISS."



Now, please stop bringing up this idea of flying X-37 to ISS, as it is simply not feasible.

[simonbp]

And the space.com article has renders of the stock X-37B berthing to ISS...

[spectre9]

Hello. I'm new here been reading for a few days and now want to join in and start posting 

Seems like all the technology developed in the unmanned version would make this possible very quickly.

Could they deliver astronauts to the ISS before Dragon?

[Sparky]

Hello. I'm new here been reading for a few days and now want to join in and start posting 

Welcome!

Seems like all the technology developed in the unmanned version would make this possible very quickly.

Could they deliver astronauts to the ISS before Dragon?

No. Even if the payload capacity were increased to include adequate life support, the current X37 launches inside a closed fairing on an Atlas V. Any manned system would need to have an abort system that would allow the spacecraft to be pulled from the rocket in the event of an emergency. Such a system would take a while to develop for a crewed variant.

[DeanG1967]

Could they deliver astronauts to the ISS before Dragon?

Ok everyone...lets give the real answer. 

Would the size of the current vehicle allow carriage of human sized cargo to the ISS?  Answer is yes.  You could put someone inside a X-37 right now and reach ISS (although there is no human lifesupport built into it and no docking mechanism to mate with the ISS).

What was trying to be explained above is that NASA has requirements for crew safety.  Currently, one is a Launch abort system (a way to get the crew away from a failed rocket).  Right now that is not available in the current X-37 launch configuration.  Could it be devised?  Yes, but it will take quite a bit of time.

[Robotbeat]

Could they deliver astronauts to the ISS before Dragon?

Ok everyone...lets give the real answer. 

Would the size of the current vehicle allow carriage of human sized cargo to the ISS?  Answer is yes.  You could put someone inside a X-37 right now and reach ISS (although there is no human lifesupport built into it and no docking mechanism to mate with the ISS).

What was trying to be explained above is that NASA has requirements for crew safety.  Currently, one is a Launch abort system (a way to get the crew away from a failed rocket).  Right now that is not available in the current X-37 launch configuration.  Could it be devised?  Yes, but it will take quite a bit of time.

Could they stuff a body into the X-37 and send it to ISS before Dragon could do the same thing? Actually, no, probably not. Dragon is set to launch in just a few months (the rocket is at the pad), whereas X-37B is in orbit with a different inclination than ISS and (we can be reasonably certain) has no body stuffed into it.

They could stuff somebody inside that Dragon, and if somehow all the docking procedures were sped up (and that person had a sufficient air supply), it's theoretically possible they could reach ISS alive. It'd be absolutely crazy and stupid (on so many levels!) to do that, but in no way is X-37b closer to doing that than Dragon is.

[Jason1701]

The attributes of the X-37 conflict almost wholly with those required of a crew-carrying spacecraft.

[spectre9]

Thanks for the great answers guys.

That's the kind of well thought out responses you like to get.

Couldn't they just launch it without the fairing with some kind of launch escape motor on top of the nose?

I'm sick of hearing about escape system developments. Surely it's been done so much now that it doesn't take heaps of time.

[Rocket Science]

More "baby shuttles"...

[arkaska]

Even though it is unlikely this will ever come to be it would be a great addition to ISS. It will give us a way to bring up ORUs previously only the shuttle could bring up.

[Jim]

from the AvWeek story:

"The X-37B evolution study, which harks back to the pre-military NASA origins of the OTV, envisages a three-phase buildup. The first would see the current 29-ft.-long vehicle used for demonstration flights to the ISS."

Now, please stop bringing up this idea of flying X-37 to ISS, as it is simply not feasible.

Some people believe marketing spin as gospel

[HIPAR]

So someone climbs into it and waits while the fairings are attached. Then the Atlas rocket is rolled out to the pad and the occupant waits while everyone conducts the launch/countdown ritual.  Then the launch is cancelled with four seconds on the clock.  The occupant waits while the rocket is rolled back to the assembly building and the fairings are removed.

Worst than riding in a Mercury space capsule.

Phuu!

---  CHAS

[Rocket Science]

So someone climbs into it and waits while the fairings are attached. Then the Atlas rocket is rolled out to the pad and the occupant waits while everyone conducts the launch/countdown ritual.  Then the launch is cancelled with four seconds on the clock.  The occupant waits while the rocket is rolled back to the assembly building and the fairings are removed.

Worst than riding in a Mercury space capsule.

Phuu!

---  CHAS

The "C" in the space.com link has no fairing...

[Space Pete]

Even though it is unlikely this will ever come to be it would be a great addition to ISS. It will give us a way to bring up ORUs previously only the shuttle could bring up.

This, in my opinion, is the single biggest advantage of X-37 to ISS, since this is a unique capability that only the X-37 can offer.

Crew transport and low-G landings could be provided by the Dream Chaser, which is much further along in terms of crewed development than the X-37 is, and so I really can't see NASA or Boeing having too much drive to develop a crewed version of the X-37.

X-37, however, is the only vehicle for the foreseeable future that can provide external ORU return from the ISS (such as the PM returned on STS-135). The question is, would the "market" for external ORU return justify developing the scaled-up X-37C? Probably not, so I think that a modified X-37B might be the only X-37 we'll see going to ISS.

[Jim]

X-37b going to ISS is almost nil

[Jim]

Huh?  Name an ORU that weighs less than 400lb.   HTV and Dragon can deliver ORUs

Chances that X-37 goes to ISS are close to nil

[Danderman]

X-37b going to ISS is almost nil

Its that infinitesimally small probability that is the basis for the new X-37 threads.

[Prober]

Even though it is unlikely this will ever come to be it would be a great addition to ISS. It will give us a way to bring up ORUs previously only the shuttle could bring up.

This, in my opinion, is the single biggest advantage of X-37 to ISS, since this is a unique capability that only the X-37 can offer.

Everyone misses the real “asset” of the x37b program.    It’s further along, tested, and it works!   That’s the real excitement here.   

NASA could have a real winner here and doesn’t really know it.  Right now I would love to see NASA work with USAF on this. Given the specs of the X37 run a test to fly to the ISS (no birthing) and after sometime return.     

This is a “mission change” for the test program, but could be well worth it in the future.  The Original design specs might have changed.   Some of the published x37b specs have an uber high orbit (much higher than the ISS).

[Jason1701]

This is a “mission change” for the test program, but could be well worth it in the future.  The Original design specs might have changed.   Some of the published x37b specs have an uber high orbit (much higher than the ISS).

... which goes to show that X-37 has far more performance in some respects than is needed for ISS resupply, and is woefully deficient in others.

MSL has some attributes in common with an ISS Crew Return Vehicle, but I don't see threads about that.

[Rocket Science]

This could be Boeing playing mind games with SNC…

[Jorge]

This could be Boeing playing mind games with SNC…

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

[arkaska]

Huh?  Name an ORU that weighs less than 400lb.   HTV and Dragon can deliver ORUs

Chances that X-37 goes to ISS are close to nil

There are however large ORU's that can't be delivered by HTV/Dragon but can be delivered by X-37C. I know that chance that it will fly is almost zero but the article is there so the discussion is appropriate.

[Jim]

ORU's can be delivered by any powerpoint spacecraft 

[Jim]

[quote author=Prober link=topic=27010.msg816627#msg816627 


NASA could have a real winner here and doesn’t really know it.  Right now I would love to see NASA work with USAF on this. Given the specs of the X37 run a test to fly to the ISS (no birthing) and after sometime return.     

This is a “mission change” for the test program, but could be well worth it in the future.  The Original design specs might have changed.   Some of the published x37b specs have an uber high orbit (much higher than the ISS).

[/quote]

There is no point for such a test.  It provides no benefit to NASA

[Prober]

This could be Boeing playing mind games with SNC…

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

Sorry but NASA can't tell Darpa or the USAF what to do.

[Jim]

Huh?

Jorge wasnt talking about the USAF(DARPA is not involved anymore), he was talking about Boeing and it proposals to NASA

[Prober]

[quote author=Prober link=topic=27010.msg816627#msg816627 


NASA could have a real winner here and doesn’t really know it.  Right now I would love to see NASA work with USAF on this. Given the specs of the X37 run a test to fly to the ISS (no birthing) and after sometime return.     

This is a “mission change” for the test program, but could be well worth it in the future.  The Original design specs might have changed.   Some of the published x37b specs have an uber high orbit (much higher than the ISS).

There is no point for such a test.  It provides no benefit to NASA
[/quote]

This could the backup plan many are looking for?

As a general rule testing the automation of the Vehicle would be good for all interested parties.

Say enough fuel for 30 days operation.
Run the standard Cots 3 programs of Orbital or SpaceX.

IMHO, if those tests provide "Valuable data" for those two companies, than a test of this vehicle is also valid.

[Jorge]

This could be Boeing playing mind games with SNC…

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

Sorry but NASA can't tell Darpa or the USAF what to do.

Wrong. For crew/cargo to ISS, NASA damn well can tell them what to do, and they will.

[Prober]

Huh?

Jorge wasnt talking about the USAF(DARPA is not involved anymore), he was talking about Boeing and it proposals to NASA

and I say you can't put a price on "testing".  It would be very valuable to all parties.   Who says they can't be brought in on this?

[Jim]

[

This could the backup plan many are looking for?

As a general rule testing the automation of the Vehicle would be good for all interested parties.

Say enough fuel for 30 days operation.
Run the standard Cots 3 programs of Orbital or SpaceX.

IMHO, if those tests provide "Valuable data" for those two companies, than a test of this vehicle is also valid.

No, no and noquote

No, there is no backup plan it can be used for nor is there one needed for cargo.

No,

No,  it does not privide useful data because there is no ISS role fir it

[Jorge]

Huh?

Jorge wasnt talking about the USAF(DARPA is not involved anymore), he was talking about Boeing and it proposals to NASA

and I say you can't put a price on "testing".

You're entitled to your opinion. I disagree. A price is put on testing all the time.

  It would be very valuable to all parties.   Who says they can't be brought in on this?

NASA's budget is already stretched thin. The money will have to come from somewhere. If DARPA/USAF/Boeing want to do standalone manned tests on their own dime, they are welcome to do so and there is no need for NASA to contribute funds. If Boeing wants to send this thing to ISS, they must conform to NASA's VV/Commercial Crew requirements, and they must do so without making their DARPA/USAF customer unhappy.

[erioladastra]

This could be Boeing playing mind games with SNC…

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

NASA has no reason to put a stop to it - they aren't paying for it and if it could lead to another vehicle the better for them.  And it might help the CST or other vehicles - though with the military shorud around it blackwalling it that may be unlikely.

[Space Pete]

HTV and Dragon can deliver ORUs

Yes, but not return.

[Jorge]

This could be Boeing playing mind games with SNC…

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

NASA has no reason to put a stop to it - they aren't paying for it and if it could lead to another vehicle the better for them.

Of course they aren't paying for it *now*. But Boeing wouldn't be pushing this vehicle for the ISS crew/cargo role unless they expected NASA to pay for it in the *future*. *That* is what I'm talking about. I thought it was obvious enough I didn't need to spell it out.

Anyway, I believe it is already NASA policy to only accept one proposal per company for CRS/CCDev/CCP awards, so a collision with CST-100 is inevitable at some point if this goes forward.

  And it might help the CST or other vehicles - though with the military shorud around it blackwalling it that may be unlikely.

I consider it *vanishingly* unlikely, and fraught with potential for unintended consequences (see Hubble).

[Jim]

Huh?

Jorge wasnt talking about the USAF(DARPA is not involved anymore), he was talking about Boeing and it proposals to NASA

and I say you can't put a price on "testing".  It would be very valuable to all parties.   Who says they can't be brought in on this?

It is not valuable to NASA, since they have  no use for it

[Patchouli]

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

Or Boeing trying to market a vehicle they already have flying for on demand cargo so they can demonstrate something before OSC and Spacex become too entrenched.
It also could test rendezvous systems for the CST-100.
A lidar and radar is not going to care what it's attached to Spacex and the Orion team used the Shuttle to test their systems.

Crew would have to wait until the X-37C putting a crew member inside the X-37B is crazy talk it would be less insane to ride the cargo version of Dragon.

They could be considering the X-37C as their next step if the CST-100 works out well to stay ahead of the competition.
Lets face it Spacex's block II Dragon and SNC's Dream Chaser are a lot snazzier then the CST-100 and probably cheaper to operate.

[clongton]

Boeing is probably just fulfilling the terms of its DoD contract.

[Prober]

All good points, however all are still missing the point of this new technology.   The info out there says 40 new embeded technologies are in this project.

The real “asset” of the x37b program.    It’s further along, tested, and it works!   That’s the real excitement here.   

To those who say its not worth further testing, why not, It works! Launch to long orbit, and auto return.   Alot of decent ideas to build on.

Speaking for myself.....have half a dozen "Derivatives" on paper before this article came out.

I'll list two (in very general terms).
1) Emergency ISS lifeboat
2) X37B = USA Progress

Won't go into details, get paid for that.

[Jim]

If it works, it needs no further testing.

As far as a US "Progress", it is no better suited than Dragon or Cygnus.

As for lifeboat, CST-100 or Dragon make a better one.

As for your other ideas, there is nothing new under the sun.  They have already been thought of years ago and there is nothing special about the X-37 WRT space station operations

[Jim]

X-37 is not "new" technology.  As for the embedded ones, they are like new valves, or TPS.  The vehicle as a whole is nothing new, just different

[Prober]

[

This could the backup plan many are looking for?

As a general rule testing the automation of the Vehicle would be good for all interested parties.

Say enough fuel for 30 days operation.
Run the standard Cots 3 programs of Orbital or SpaceX.

IMHO, if those tests provide "Valuable data" for those two companies, than a test of this vehicle is also valid.

No, no and noquote

No, there is no backup plan it can be used for nor is there one needed for cargo.

No,

No,  it does not privide useful data because there is no ISS role fir it

your messages are not logical.....Darpa, NASA, and USAF, Boeing would not have all invested funds if some good use could come out of the investment.

your talking in the wrong place about "backup" talk that up to Congress etc.

[Prober]

If it works, it needs no further testing.

As far as a US "Progress", it is no better suited than Dragon or Cygnus.

As for lifeboat, CST-100 or Dragon make a better one.

As for your other ideas, there is nothing new under the sun.  They have already been thought of years ago and there is nothing special about the X-37 WRT space station operations

1) your playing games now, bad Jim you know this would be a different mission profile.
2) reusable, runway landings
3) IYHO
4) You don't have enough proper data for such a statement.


btw Jim if you would like to meet and show me the error of my ways.....I'm trying to pencil in a VAFB launch & also http://www.nellis.af.mil/aviationnation/

[yg1968]

This could be Boeing playing mind games with SNC…

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

The CCDev-2 rules were clear on that point. You are only allowed to have one proposal where you are the main participant. Boeing needs to make a choice. However, you are also allowed to participate in other proposals as long as you remain a minority participant.

[clongton]

The CCDev-2 rules were clear on that point. You are only allowed to have one proposal where you are the main participant. Boeing needs to make a choice.

Boeing doesn't need to make a choice. X-37 is not a CCDev contestant. It is a USAF project only. Boeing has many other projects it is also working on and none of them are CCDev contestants either. Boeing has only one CCDev project underway: CST-100.

[Jim]

2) reusable, runway landings
3) IYHO
4) You don't have enough proper data for such a statement.


5 btw Jim if you would like to meet and show me the error of my ways.....I'm trying to pencil in a VAFB launch & also http://www.nellis.af.mil/aviationnation/

2.  That doesn't provide any advantages.
a.  Dragon is reusable
b.  US has cargo vehicles in development
c.  Progress only docks to the Russians segment
D.  The US does not need a Progress vehicle since the US segment has no propellant needs
3. No, Dragon and CST-100 do make better lifeboats because they are more robust  and don't need runways. (the earth is 70% water,  wings and landing gear are useless )
4.  Yes, I do have enough data.  A winged logstics has been flying for 30 years and others have been planned for longer.  There is nothing new under the sun.
 

[CitabriaFlyer]

There seem to be several interesting points of debate.

1)  Is a winged vehicle desirable?

2)  Which is the better winged vehicle?

3)  Can Boeing build two spaceships?

To the first point:
A winged vehicle has advantages in terms of 1) return of delicate equipment 2) aerovac  3) appeal to aesthetics.  Don't underestimate the importance of 3.  Going back to the 50s, maybe earlier people like von Braun and Clarke wrote about spaceplanes.  They look beautiful and intuitive and this is going to appeal to the congressmen and taxpayers who pay for these things and the astronauts who will fly them.  I concede that there are very valid criticisms to these points, especially in 2011.  The market may not be ready for spaceplanes for another 30 years.  Fifty years separate the X-15 and SS2.

To the second point: 
This is the question I am most interested in.  If there is a desire for a winged vehicle this decade which is the superior product X-37 or DreamChaser? 

To the third point:
I think Boeing could build two spacecraft if the market demanded it.  The commercial contracts can always be modified to allow that.  Certainly there is a role for both the 747 and 737.

[Ben the Space Brit]

A heretical suggestion:

The X-37 is just a technology research program and USAF have no firm or funded plans to develop it into any kind of operational vehicle.  Recognising that their jobs will soon be over, the X-37 team at Boeing are throwing ideas out in a hope that it will attract some NASA CCDev or general R&D cash to keep them in employment.

[edkyle99]

A heretical suggestion:

The X-37 is just a technology research program and USAF have no firm or funded plans to develop it into any kind of operational vehicle.  Recognising that their jobs will soon be over, the X-37 team at Boeing are throwing ideas out in a hope that it will attract some NASA CCDev or general R&D cash to keep them in employment.

That suggestion seems likely, rather than heretical, to me.  Unless this thing has a hidden, Howard Hughes Glomar Explorer-like mission, I can't figure out what it's for. 

 - Ed Kyle

[beb]

This X-37C proposal is best seen in light of the many Apollo Application proposals that came out in the late 60s/ early 70s. They were efforts by the contractors to come up with new uses for their product (Apollo) that would allow continued consumption of the product. Some of these were god ideas, some were kind of crazy. But mostly they were out there to get more work for the company.

The X-37b folk can see the brick wall at the end of the gravy train. So they're floating ideas to keep moving forward. X-37C has good ideas but it's also pretty comparable to Dream Chaser, too. We don't need two glider spacecraft.

[Rocket Science]

The “C” has been specified to service the ISS, “I” as in international… It could be made available to other space agencies… We should not be so nationalistic in our thinking on a international project.

Regards
Robert

[Prober]

A heretical suggestion:

The X-37 is just a technology research program and USAF have no firm or funded plans to develop it into any kind of operational vehicle.  Recognising that their jobs will soon be over, the X-37 team at Boeing are throwing ideas out in a hope that it will attract some NASA CCDev or general R&D cash to keep them in employment.

thats possible, yet the Boeing team was allowed to make the presentation.  So Boeing could be blessing this, or thowing it out to see if it will stick?

[Prober]

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

Crew would have to wait until the X-37C putting a crew member inside the X-37B is crazy talk it would be less insane to ride the cargo version of Dragon.

I wouldn't put crew in the X-37C or a cargo version of the Dragon.  Both are not ready.

Having said that, the X-37B has more proven orbital space time.  That also needs to be considered.

[Jim]

X-37"C" as not been built, the B model is the one onorbit.

That aside, the amount of time the X-37B has been in space is meaningless engineeringwise.  Mission duration is not hard to achieve.

[CitabriaFlyer]

What are the feelings about X-37C vs DreamChaser?

[Prober]

What are the feelings about X-37C vs DreamChaser?

Sounds like a new thread.

[Namechange User]

What are the feelings about X-37C vs DreamChaser?

Sounds like a new thread.

Why?  This is what confuses me so about "advocates" and/or the "space community".  What do "feelings" have to do with any of it?

First "we" are told that there IS a market.  That competition is good and the market will decide (implying we should WANT more possible vehicles).  In the next breath, there is seemingly only room for so many and no "others" are welcome and "commercial" must be a choice essentially between Boeing, SpaceX, Sierra Nevada and Blue Origin and only the designs that are known thus far which culminate in "versus" threads. 

It's odd to me personally but at the same time "I" am told by the "advocates" that "I" am supposed to take at face value that 10,000 jobs will be created, that SLS is a failure and pork, that SpaceX is the end-all and be-all (even though Falcon has launched only twice and it was not perfect), that more government money MUST be given to commercial, etc, etc, etc.

Just a little venting......

[docmordrid]

Ever hear of an Air War College paper called Wild Ride?

Link....(PDF)

[Patchouli]

This could be Boeing playing mind games with SNC…

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

The CCDev-2 rules were clear on that point. You are only allowed to have one proposal where you are the main participant. Boeing needs to make a choice. However, you are also allowed to participate in other proposals as long as you remain a minority participant.

If I was in their position I'd combine the two programs.

Since the X-37 has flight experience and aircraft work is not difficult for Boeing I'd go with the X-37C as the combined program.

A capsule is not necessarily safer then a space plane that is a complete fallacy in fact  flight history of past vehicles shows the opposite.

Though ITAR is going to be a far better decider here then anything technical but I feel the X-37C would have both lower reoccurring costs and would be safer then the CST-100.

[Namechange User]

Ever hear of an Air War College paper called Wild Ride?

Link....(PDF)

Sure.  But here is the problem with that.

What possible need is so great that we must launch and send some Marines through space to get them to the other side of the planet that quickly and in that way?

What happens to extract the Team after their objective is complete?  What about the vehicle?  Do we leave it?  Do we blow it up?

Look at the Bin Laden experience and see what happens there.  Clearly we have a stealth helicopter that we had to destroy and look what happened with the Chinese, etc. 

Are we prepared to surrender space plane technology to foreign interests at every operational use?

[Patchouli]

Ever hear of an Air War College paper called Wild Ride?

Link....(PDF)

Sure.  But here is the problem with that.

What possible need is so great that we must launch and send some Marines through space to get them to the other side of the planet that quickly and in that way?

What happens to extract the Team after their objective is complete?  What about the vehicle?  Do we leave it?  Do we blow it up?

Look at the Bin Laden experience and see what happens there.  Clearly we have a stealth helicopter that we had to destroy and look what happened with the Chinese, etc. 

Are we prepared to surrender space plane technology to foreign interests at every operational use?

I always wondered the same thing.

Landing probably would not be a big deal for a small space plane as it probably could land at almost any airport or even a highway but getting it back would be a pain.

You'd have to send a Chinook to get the landing vehicle and crew and it probably would be very close to the max payload.

Maybe if it also had air breathing engines and could be flown back like a normal jet at sub to low super sonic speeds but you'd still need a good spot to land and take off.

The range would probably would not be very good either as hyper sonic shapes generally do not make good sub sonic shapes.

[docmordrid]

As far as forward insertion goes I refer you to Operation Overlord where we dropped disposable gliders in behind lines for special ops, and the fact that such troops have been HALO jumping to do the same for decades. This would allow the same hotzone maneuver worldwide within hours.

Nothing says the transport has to be returnable or reusable. Just enough to make the trip and landing is enough. Extraction is often different than insertion, nothing new there, and some missions only return if their own advancing forces overtake them. Some missions don't. Welcome to USSOCOM.

[Namechange User]

I always wondered the same thing you'd have to send a Chinook to get the vehicle and it probably would be very close to the max payload.

Right, if you don't plan on destroying it.  And if you need to send a team into a hostile zone to recover your people AND spaceship then operationally speaking it is more efficient and safer to just send in the equipment to extract the Team (assuming they did not come in on something and it is not loitering, etc for them)

Besides, we pretty much reach across the world right now with current capabilities and nothing says, "Hey, I'm coming" like a hypersonic vehicle from space descending into your country. 

[Patchouli]

I always wondered the same thing you'd have to send a Chinook to get the vehicle and it probably would be very close to the max payload.

Right, if you don't plan on destroying it.  And if you need to send a team into a hostile zone to recover your people AND spaceship then operationally speaking it is more efficient and safer to just send in the equipment to extract the Team (assuming they did not come in on something and it is not loitering, etc for them)

Besides, we pretty much reach across the world right now with current capabilities and nothing says, "Hey, I'm coming" like a hypersonic vehicle from space descending into your country. 

Dangerous as heck but I wonder if a VTOL like DCY would be better as it can land anywhere.

Just make sure you have enough fuel to hop back to somewhere friendly.

More useful would be to employ your space plane as a glide skip bomber.

[docmordrid]

But what reaction time would they have to a fast incoming doing a precision landing? A lot shorter than to an airdrop I'd bet, and those are done all the time.

[Patchouli]

The craziest concept for fast intercontinental troop delivery I ever seen was Ithacus.
http://www.astronautix.com/craft/ithacus.htm

[Namechange User]

But what reaction time would they have to a fast incoming doing a precision landing? A lot shorter than to an airdrop I'd bet, and those are done all the time.

Well no.  You have sonic booms, etc.  Where does one do a "precision landing" in hostile territory that meets the requirements to actually land but remote enough that no one will be there or is not a target on the ground.  What if that landing area is nowhere near the reason the Team is going in the first place?  How do you get them out afterward?

[Prober]

This could be Boeing playing mind games with SNC…

Or it could be the Boeing X-37 team playing mind games with the Boeing CST-100 team.

NASA could put a stop to this really quick by telling Boeing Corporate that NASA will only fund one or the other.

The CCDev-2 rules were clear on that point. You are only allowed to have one proposal where you are the main participant. Boeing needs to make a choice. However, you are also allowed to participate in other proposals as long as you remain a minority participant.

If I was in their position I'd combine the two programs.

Since the X-37 has flight experience and aircraft work is not difficult for Boeing I'd go with the X-37C as the combined program.

A capsule is not necessarily safer then a space plane that is a complete fallacy in fact  flight history of past vehicles shows the opposite.

Though ITAR is going to be a far better decider here then anything technical but I feel the X-37C would have both lower reoccurring costs and would be safer then the CST-100.

Maybe things are alot closer then we think. 

Jim let the poor guy return, he must be getting hungry...hhhehhe

[Jim]

A capsule is not necessarily safer then a space plane that is a complete fallacy in fact  flight history of past vehicles shows the opposite.

Wrong as usual.

[BrightLight]

A capsule is not necessarily safer then a space plane that is a complete fallacy in fact  flight history of past vehicles shows the opposite.

Wrong as usual.

This comes up periodically on the forum -  Is there a reference on the safety and reliability of winged RV, lifting bodies and capsules.  Someone must have done an analysis at some point. 

[yg1968]

The CCDev-2 rules were clear on that point. You are only allowed to have one proposal where you are the main participant. Boeing needs to make a choice.

Boeing doesn't need to make a choice. X-37 is not a CCDev contestant. It is a USAF project only. Boeing has many other projects it is also working on and none of them are CCDev contestants either. Boeing has only one CCDev project underway: CST-100.

Yes I know. I meant that Boeing cannot ask NASA to fund the X-37C for CCDev-3 unless it drops the CST-100 or if it transfers the project to Bigelow. I am not expecting that to happen because I expect Boeing to continue with the CST-100 for CCDev-3 and 4.

[Jorge]

This X-37C proposal is best seen in light of the many Apollo Application proposals that came out in the late 60s/ early 70s. They were efforts by the contractors to come up with new uses for their product (Apollo) that would allow continued consumption of the product. Some of these were god ideas, some were kind of crazy. But mostly they were out there to get more work for the company.

The X-37b folk can see the brick wall at the end of the gravy train. So they're floating ideas to keep moving forward.

It reminds me of the flurry of MDAC Gemini variants as well.

[Prober]

Anyone seen/read the X37C paper AIAA-2011-7315 ?

[Patchouli]

A capsule is not necessarily safer then a space plane that is a complete fallacy in fact  flight history of past vehicles shows the opposite.

Wrong as usual.

This comes up periodically on the forum -  Is there a reference on the safety and reliability of winged RV, lifting bodies and capsules.  Someone must have done an analysis at some point. 

On paper a capsule seems safer but in practice the Shuttle and X-15 programs have demonstrated that landing as a glider generally is much safer then then using parachutes and splashing down.

The plane side of things is often is argued as a failure mode but this is probably the safest part of the system as the avionics and control systems are similar to those on airliners and are very robust systems.
The LV and spacecraft end of things are far more likely to cause an LOC event.
The  biggest advantage a capsule has is the main TPS is covered by a service module or in Dragon's case a trunk.

But other risks like separation events could overshadow this and on orbit repair and redundant TPS could reduce it's risk.
Though some space planes have separation events such as Kliper and Hermes.
Slash downs are risky esp considering the recovery team also is at risk vs just the crew in the descent vehicle.
The weather needs to be perfect if possible.
One reason why Spacex wants to land on land.

[Jim]

On paper a capsule seems safer but in practice the Shuttle and X-15 programs have demonstrated that landing as a glider generally is much safer then then using parachutes and splashing down.

Wrong again. Shuttle and X-15 have demonstrated the opposite.  How many landing accidents were in the X-15?  How many pilots were lost in X-15? Columbia?  Soyuz 1 is the only strike against capsules.  All other issues with capsules show their robustness. 

[BrightLight]

A capsule is not necessarily safer then a space plane that is a complete fallacy in fact  flight history of past vehicles shows the opposite.

Wrong as usual.

This comes up periodically on the forum -  Is there a reference on the safety and reliability of winged RV, lifting bodies and capsules.  Someone must have done an analysis at some point. 

On paper a capsule seems safer but in practice the Shuttle and X-15 programs have demonstrated that landing as a glider generally is much safer then then using parachutes and splashing down.

The plane side of things is often is argued as a failure mode but this is probably the safest part of the system as the avionics and control systems are similar to those on airliners and are very robust systems.

The  biggest advantage a capsule has is the main TPS is covered by a service module.

But other risks like separation events could overshadow this and on orbit repair and redundant TPS could reduce it's risk.

I have looked at cost analysis of various RV's and I think it will boil down to the number of people used to maintain the craft between flights.  There might be a break point of something like 7:1 for flight engineers to support.  However, I can't find a model that can simulate the safety/reliability of RV's, so for example the higher temperature a lifting body will encounter on reentry as compared to a blunt body might be offset by not having to use parachutes (and there failure modes).  I am sure that there are many trades and I suspect not simple ones at that.

[BrightLight]

On paper a capsule seems safer but in practice the Shuttle and X-15 programs have demonstrated that landing as a glider generally is much safer then then using parachutes and splashing down.

Wrong again. Shuttle and X-15 have demonstrated the opposite.  How many landing accidents were in the X-15?  How many pilots were lost in X-15? Columbia?  Soyuz 1 is the only strike against capsules.  All other issues with capsules show their robustness. 

How many RV's - manned and unmanned using the capsule design have failed? It is the design that is in question.  The manned capsule systems - thank goodness - have performed well, although the Russian systems periodically land in the wrong place, as have American systems i.e. Mercury.  Does cross range affect safety and reliability, I think so.

[Patchouli]

On paper a capsule seems safer but in practice the Shuttle and X-15 programs have demonstrated that landing as a glider generally is much safer then then using parachutes and splashing down.

Wrong again. Shuttle and X-15 have demonstrated the opposite.  How many landing accidents were in the X-15?  How many pilots were lost in X-15? Columbia?  Soyuz 1 is the only strike against capsules.  All other issues with capsules show their robustness. 

There was only one landing fatality with the X-15 and that was due to pilot disorientation.
Columbia was not directly due to it being a space plane but just as much as it riding the side of the LV stack.
The X-37C would not be subject to LV debris.

It should be noted Liberty Bell 7,Soyuz 23, and ASTP were close LOC events partly related to the descent and landing mode.
The two cosmonauts surviving Soyuz 18a was sheer luck vs anything else.
There also has been a few instances of hard landings on Soyuz resulting in injury.

Engineering and QM along with paying attention to weather probably completely over shadow any inherent safety or danger of a landing mode.

I'd still prefer a capsule for long BEO mission return because the TPS is covered and for mass savings but for LEO a space plane seems better suited.

[BrightLight]

On paper a capsule seems safer but in practice the Shuttle and X-15 programs have demonstrated that landing as a glider generally is much safer then then using parachutes and splashing down.

Wrong again. Shuttle and X-15 have demonstrated the opposite.  How many landing accidents were in the X-15?  How many pilots were lost in X-15? Columbia?  Soyuz 1 is the only strike against capsules.  All other issues with capsules show their robustness. 

There was only one landing fatality with the X-15 and that was due to pilot disorientation.
Columbia was not directly due to it being a space plane but just as much as it riding the side of the LV stack.
The X-37C would not be subject to LV debris.

It should be noted Liberty Bell 7,Soyuz 23, and ASTP were close LOC events partly related to the descent and landing mode.
The two cosmonauts surviving Soyuz 18a was sheer luck vs anything else.
There also has been a few instances of hard landings on Soyuz resulting in injury.

Over all they're probably equal if anything and there likely is no simple yes no answer which is why all the private vehicle are each going for very different entry and landing modes.

I'd still prefer a capsule for long BEO mission return because the TPS is covered and for mass savings but for LEO a space plane seems better.

Aside from the Shuttle, lifting bodies made almost 150 landings from altitude with 1 fatality early in the lifting body program (M2F2 I believe)
One of the main reasons why intel systems stopped using film return was the issue of capsule RV reliability.  Both the US and the Russians have a lot of experience using both capsule and lifting body RV's and it should be possible to determine the utility of both systems quantitatively, I just don't know how at this point.

[Patchouli]

Well there's another issue a spy sat with film return RVs becomes space junk once all the RVs are used up while a sat with digital com links only has to deal with running out of fuel and equipment break downs.

[BrightLight]

If we add the heavy lifting body landings (X-24, HL-10, M2F2, M2F3) and the shuttle landings - 135 minus two (some very sad days) and take into account that the shuttle LOC's were due to LV design not the RV, that is about 283 landings - not including ASSET, PRIME and BOR vehicles, that give us a reliability of about 0.9964. Not the 1 in 2000 some programs have attempted on paper but still respectable.

[Robotbeat]

This X-37C proposal is best seen in light of the many Apollo Application proposals that came out in the late 60s/ early 70s. They were efforts by the contractors to come up with new uses for their product (Apollo) that would allow continued consumption of the product. Some of these were god ideas, some were kind of crazy. But mostly they were out there to get more work for the company.
...

This. (And it applies to other ideas kicked around here, too.)

[GClark]

X-15s killed two pilots:  Mike Adams in the #3 crash (disorientation, but the computer going into a rate-limit cycle didn't help) and Jack McKay (not directly; the injuries he suffered in the #2 crash did lead to his untimely death).  They came pretty close to getting Scott Crossfield more than once.

Noone has ever died piloting a lifting body.  The M2-F1, HL-10, and M2-F2 all tried to kill Bruce Peterson.  The M2-F2 came closest - as bad as that crash looks, he only (!) lost an eye.

Note:  The M2-F2 is the only lifting body that ever actually crashed (so far).

[Sparky]

Ever hear of an Air War College paper called Wild Ride?

Link....(PDF)

Sure.  But here is the problem with that.

What possible need is so great that we must launch and send some Marines through space to get them to the other side of the planet that quickly and in that way?

What happens to extract the Team after their objective is complete?  What about the vehicle?  Do we leave it?  Do we blow it up?

Look at the Bin Laden experience and see what happens there.  Clearly we have a stealth helicopter that we had to destroy and look what happened with the Chinese, etc. 

Are we prepared to surrender space plane technology to foreign interests at every operational use?

I always wondered the same thing.

Landing probably would not be a big deal for a small space plane as it probably could land at almost any airport or even a highway but getting it back would be a pain.

You'd have to send a Chinook to get the landing vehicle and crew and it probably would be very close to the max payload.

Maybe if it also had air breathing engines and could be flown back like a normal jet at sub to low super sonic speeds but you'd still need a good spot to land and take off.

The range would probably would not be very good either as hyper sonic shapes generally do not make good sub sonic shapes.

Not to mention the issues regarding the launch vehicle. Would there be an Atlas V with a crew capable X37 derivative sitting on the pad at all times, with a rotating crew of marines stationed with it, just waiting to be launched into a combat zone at the notice of the president? Can an Atlas V even be maintained indefinitely? Are there any existing first-strike ICBMs in service that could carry an X37C? (I'm guessing not)

Also, given what we know about how long it takes to produce launch vehicles, what happens if you have a second crisis within 1 or 2 years of the mission? There would likely need to be a reserve of additional rockets on standby to avoid losing the capabilities of the vehicle for any length of time following a flight.

Launch issues aside, I wonder if the Marines could bail out over the target zone, and allow the vehicle to continue it's glide toward a friendly landing strip, or to crash into the surface if necessary. Extraction would need to occur by some other method, needless to say.

[happyflower]

To me the defining technology of the shuttle was its TPS. I remember the first time I saw that picture with the guy holding a glowing red cube in his bare hand. The TPS technology should be provided to the private sector as the inflatable habitat technology was.

The X37C can be anything still. It could easily be enlarged to fit on top of a Atlas V and launched to space stations. The wings will certainly give it one advantage to capsules and that is a very low G landing (probably close to 1). This would be on par in comfort with a SpaceShip2.

This maybe a stunt by Boeing, but the idea of a winged orbital plane with TPS that is launched "on top" of a rocket is solid engineering.

[Jim]

Aside from the Shuttle, lifting bodies made almost 150 landings from altitude with 1 fatality early in the lifting body program (M2F2 I believe)
One of the main reasons why intel systems stopped using film return was the issue of capsule RV reliability.

Wrong and unsubstantiated, it had nothing to do with SRV's or their reliability.  But anyways, they were very reliable and that is why the same systems were used for so long.

[Jim]

Well there's another issue a spy sat with film return RVs becomes space junk once all the RVs are used up while a sat with digital com links only has to deal with running out of fuel and equipment break downs.

Wrong again, it wasn't an issue, they were deorbited just like the digital ones are.

Why don't you stop making statements that are wrong.

[Jim]

It should be noted Liberty Bell 7,Soyuz 23, and ASTP were close LOC events partly related to the descent and landing mode.

Wrong again.

ASTP has nothing to do with the landing mode.  The Shuttle has the same hazard

[Jim]

If we add the heavy lifting body landings (X-24, HL-10, M2F2, M2F3)

No, they are not included, they did not reenter, leave the atmosphere or have significant heating.

[FinalFrontier]

On paper a capsule seems safer but in practice the Shuttle and X-15 programs have demonstrated that landing as a glider generally is much safer then then using parachutes and splashing down.

Wrong again. Shuttle and X-15 have demonstrated the opposite.  How many landing accidents were in the X-15?  How many pilots were lost in X-15? Columbia?  Soyuz 1 is the only strike against capsules.  All other issues with capsules show their robustness. 

Agreed. In addition we know from shuttle that a winged vehicle is likely to suffer 2 major design faults simply from having wings:

1. Far greater risk of damage to the heat shield during take off. This cannot be avoided because the heatshield is not protected underneath the vehicle and is far greater in size and complexity.
2. Far greater risk of damage during the missions from MMOD impacts, especially one with escape velocity involved. This again, is because of the far greater surface Area of the heat shield, as well as the fact that its not protected underneath the vehicle.



All in all, I doubt highly that any of these presentations on a crewed x37 will go anywhere beyond the realm of spin and pr, as Boeing already has plans for the crewed cst 100 vehicle,  and even if they did I think it would be a HIGHLY unsafe vehicle.

[yg1968]

I doubt the size of the TPS surface makes a huge difference. Both the X-37 and the Dream Chaser are fairly small. Plus, they have the advantage of landing on a runway. I would have thought that capsules were safer because of their LAS.

[Prober]

The X37C can be anything still. It could easily be enlarged to fit on top of a Atlas V and launched to space stations. The wings will certainly give it one advantage to capsules and that is a very low G landing (probably close to 1). This would be on par in comfort with a SpaceShip2.

This maybe a stunt by Boeing, but the idea of a winged orbital plane with TPS that is launched "on top" of a rocket is solid engineering.

you hit upon the major advantage of a wing landing.  For HSF the landings are better based on "comfort".

One thread here somewhere compared a shuttle landing to the Soyuz. 
more later.....

[BrightLight]

On paper a capsule seems safer but in practice the Shuttle and X-15 programs have demonstrated that landing as a glider generally is much safer then then using parachutes and splashing down.

Wrong again. Shuttle and X-15 have demonstrated the opposite.  How many landing accidents were in the X-15?  How many pilots were lost in X-15? Columbia?  Soyuz 1 is the only strike against capsules.  All other issues with capsules show their robustness. 

Agreed. In addition we know from shuttle that a winged vehicle is likely to suffer 2 major design faults simply from having wings:

1. Far greater risk of damage to the heat shield during take off. This cannot be avoided because the heatshield is not protected underneath the vehicle and is far greater in size and complexity.
2. Far greater risk of damage during the missions from MMOD impacts, especially one with escape velocity involved. This again, is because of the far greater surface Area of the heat shield, as well as the fact that its not protected underneath the vehicle.

All in all, I doubt highly that any of these presentations on a crewed x37 will go anywhere beyond the realm of spin and pr, as Boeing already has plans for the crewed cst 100 vehicle,  and even if they did I think it would be a HIGHLY unsafe vehicle.

The diameter of Orion's heat shield is probably larger than the x-37B and might not be much different than a 165% scaled C variant - the Dream Chaser heat shield (slipper - 9m by 7 m triangle) appears to be smaller than Orion (5 m diameter).
However, the TPS on a non shrouded lifting body is unprotected during launch and accent, exposing it to potential damage.
As I posted earlier, a reliability analysis of capsules versus space planes would be very useful.  Since Boeing is designing the CST-100 and has flown the X-37B and talking up X-37C someone thereought to have looked at this in depth?

[Ben the Space Brit]

Re.: LAS for X-37

The pictures of X-37B v1 being encapsulated made me think of possibly a pseudo-MLAS arrangement where the abort motors are on the exterior of the PLF.  They fire, pulling the spacecraft off the stack, still in the PLF; at the end of their burn, the PLF seperates leaving the S/C to glide back to land.

FWIW, a crew-sized X-37 would need an SLS-sized LV to use this arrangement.

[Jim]

FWIW, a crew-sized X-37 would need an SLS-sized LV to use this arrangement.

No, there is no fairing on a crew sized X-37

[Jim]

  Since Boeing is designing the CST-100 and has flown the X-37B and talking up X-37C someone there ought to have looked at this in depth?

No, there isn't a "one" Boeing wrt this, there are two different Boeing divisions involved.  X-37 is winding down and its Boeing group is looking for work, regardless what CST-100 is doing.

[Patchouli]

Well there's another issue a spy sat with film return RVs becomes space junk once all the RVs are used up while a sat with digital com links only has to deal with running out of fuel and equipment break downs.

Wrong again, it wasn't an issue, they were deorbited just like the digital ones are.

Why don't you stop making statements that are wrong.

deorbit = space junk being disposed of.
You take things too literally.

The X37C can be anything still. It could easily be enlarged to fit on top of a Atlas V and launched to space stations. The wings will certainly give it one advantage to capsules and that is a very low G landing (probably close to 1). This would be on par in comfort with a SpaceShip2.

This maybe a stunt by Boeing, but the idea of a winged orbital plane with TPS that is launched "on top" of a rocket is solid engineering.

you hit upon the major advantage of a wing landing.  For HSF the landings are better based on "comfort".

One thread here somewhere compared a shuttle landing to the Soyuz. 
more later.....

It doesn't make the main stream news but sometimes minor and not so minor injuries result from abnormally rough Soyuz landings.
This example was more due to an off nominal reentry vs the actual landing.
http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=space&id=news/Southkor050208.xml&headline=South%20Korean%20Astronaut%20Hospitalized

[Jim]

Well there's another issue a spy sat with film return RVs becomes space junk once all the RVs are used up while a sat with digital com links only has to deal with running out of fuel and equipment break downs.

Wrong again, it wasn't an issue, they were deorbited just like the digital ones are.

Why don't you stop making statements that are wrong.

deorbit = space junk coming down
You take things too literally.

You continually make incorrect statements.  There was no "issue".   Film return spacecraft were designed for a shorter orbital lifetime wrt propellant and equipment failure rates.  Also, the film return spacecraft had secondary missions that continued after the film was used up.  And in the end, both film and digital spacecraft were deorbited at the end of their lifetimes.

[Patchouli]

Well there's another issue a spy sat with film return RVs becomes space junk once all the RVs are used up while a sat with digital com links only has to deal with running out of fuel and equipment break downs.

Wrong again, it wasn't an issue, they were deorbited just like the digital ones are.

Why don't you stop making statements that are wrong.

deorbit = space junk coming down
You take things too literally.

You continually make incorrect statements.  There was no "issue".   Film return spacecraft were designed for a shorter orbital lifetime wrt propellant and equipment failure rates.  Also, the film return spacecraft had secondary missions that continued after the film was used up.  And in the end, both film and digital spacecraft were deorbited at the end of their lifetimes.

I didn't know they had a secondary missions I thought they were deorbited once the last reentry vehicle departed.

[Ben the Space Brit]

FWIW, a crew-sized X-37 would need an SLS-sized LV to use this arrangement.

No, there is no fairing on a crew sized X-37

This particular LAS concept would require one.  That's all I'm saying.

[simonbp]

MSL has some attributes in common with an ISS Crew Return Vehicle, but I don't see threads about that.

Holy frak, can you imagine landing on Earth just in a pressure suit with a Skycrane strapped to your back! You'd have to attach a few speakers playing the James Bond theme...

[Garrett]

I doubt the size of the TPS surface makes a huge difference. Both the X-37 and the Dream Chaser are fairly small. Plus, they have the advantage of landing on a runway. I would have thought that capsules were safer because of their LAS.

Can't winged craft have similar LAS to capsules if they're launched on top of the LV?
For me, I always thought that capsules are meant to be safer because they can re-enter off-nominally, i.e. the center of gravity and the capsule shape naturally keeps the the heat shield pointing down even in the event of a guidance system failure. A nominal re-entry is desired for lower g-forces and for landing on target.
A winged craft, on the other hand, needs a perfect re-entry to survive.

Well, that's how I saw it anyway. Am I mistaken?

[savuporo]

I have no idea why this here is under commercial spaceflight, but thats the latest thread i found on X37.
http://spaceports.blogspot.com/2012/03/x-37b-space-plane-game-changing-mission.html


Makes you go hmmmm... its vewy vewy quiet ...

[Dappa]

I have no idea why this here is under commercial spaceflight, but thats the latest thread i found on X37.

Because the latest thread is not always the right one, you meant to post it here:http://forum.nasaspaceflight.com/index.php?topic=24323.465

[vulture4]

I doubt the size of the TPS surface makes a huge difference. Both the X-37 and the Dream Chaser are fairly small. Plus, they have the advantage of landing on a runway. I would have thought that capsules were safer because of their LAS.

Can't winged craft have similar LAS to capsules if they're launched on top of the LV?
For me, I always thought that capsules are meant to be safer because they can re-enter off-nominally, i.e. the center of gravity and the capsule shape naturally keeps the the heat shield pointing down even in the event of a guidance system failure. A nominal re-entry is desired for lower g-forces and for landing on target.
A winged craft, on the other hand, needs a perfect re-entry to survive.

Well, that's how I saw it anyway. Am I mistaken?

The X-37 could use same system as Dragon, just OMS thrusters that can get it clear of the LV and up to gliding speed. You can't watch the test of the Minuteman-sized LAS on the Orion and believe it would work without very precise computer control, so I think an automated runway landing for an X-37 abort is reasonable.

In this vein, lift to drag ratio at touchdown is critical to practical landing. The X-37 is certainly superior to the Dreamchaser in this regard. Dreamchaser has a much lower lift to drag ratio than X-37C. The L/D of the X-37 is about 4.5, the DC is at about 3.5, too low for a safe landing without powered lift.

So why are we so insistent on flying _without_ wings? Why did NASA abandon X-37 and all winged entry vehicles?

[BrightLight]

 Dreamchaser has a much lower lift to drag ratio than X-37C. The L/D of the X-37 is about 4.5, the DC is at about 3.5, too low for a safe landing without powered lift.

Do you have citations or other data showing these L/D ratios? It is my impression that the DC lands un-powered as a glider?

[Jim]

So why are we so insistent on flying _without_ wings? Why did NASA abandon X-37 and all winged entry vehicles?

Because they are not needed for BEO missions.

[BrightLight]

On this site, see dream chaser Q&A thread:
DC L/D of 4.0
HL-20 L/D I thought was also in this range as well, I will see if i can find the citation.
   
Re: Dream Chaser Q&A (including suggestions and improvements)
« Reply #571 on: 05/02/2011 09:01 PM »
   
Interesting Aviation Week story.

Quote

    The Dream Chaser is expected to have a cross-range capability of 1,700 km (1,000 mi.) and with a subsonic lift/drag ratio of 4:0, a “landing will be feasible on 7,000-foot runways,” he says.


That's a pretty good L/D! (joke)

[BrightLight]

I doubt the size of the TPS surface makes a huge difference. Both the X-37 and the Dream Chaser are fairly small. Plus, they have the advantage of landing on a runway. I would have thought that capsules were safer because of their LAS.

Can't winged craft have similar LAS to capsules if they're launched on top of the LV?
For me, I always thought that capsules are meant to be safer because they can re-enter off-nominally, i.e. the center of gravity and the capsule shape naturally keeps the the heat shield pointing down even in the event of a guidance system failure. A nominal re-entry is desired for lower g-forces and for landing on target.
A winged craft, on the other hand, needs a perfect re-entry to survive.

Well, that's how I saw it anyway. Am I mistaken?

The X-37 could use same system as Dragon, just OMS thrusters that can get it clear of the LV and up to gliding speed. You can't watch the test of the Minuteman-sized LAS on the Orion and believe it would work without very precise computer control, so I think an automated runway landing for an X-37 abort is reasonable.

In this vein, lift to drag ratio at touchdown is critical to practical landing. The X-37 is certainly superior to the Dreamchaser in this regard. Dreamchaser has a much lower lift to drag ratio than X-37C. The L/D of the X-37 is about 4.5, the DC is at about 3.5, too low for a safe landing without powered lift.

So why are we so insistent on flying _without_ wings? Why did NASA abandon X-37 and all winged entry vehicles?

Sub-sonic L/D on the HL-20 is well within the 4.0 to 4.5 L/D

http://www.ninfinger.org/models/vault2008/HL-20/HL-20%20MODEL.pdf

The increased weight of the X-37C for crew etc. will have a affect on landing speed.  With similar L/D for both vehicles, the landing speed will be scaled by weight. I suspect (arm waving) the X-37C will be very similar in weight to the DC and will have landing speeds on order of 150 to 200 knots.

[vulture4]

So why are we so insistent on flying _without_ wings? Why did NASA abandon X-37 and all winged entry vehicles?

Because they are not needed for BEO missions.

I would guess a lifting body is also unneeded BEO. It does not appear that any of the commercial vehicles is intended for anything other than LEO. While all alternatives are certainly worth considering, a capsule has greater volumetric efficiency than a lifting body.

[Jason1701]

So why are we so insistent on flying _without_ wings? Why did NASA abandon X-37 and all winged entry vehicles?

Because they are not needed for BEO missions.

I would guess a lifting body is also unneeded BEO. It does not appear that any of the commercial vehicles is intended for anything other than LEO. While all alternatives are certainly worth considering, a capsule has greater volumetric efficiency than a lifting body.

Are you trying to say that all the commercial vehicles are not capsules?

Any shape other than a perfect sphere can generate lift.

[vulture4]

The Shuttle has an L/D of 4.5 during final approach.
http://en.wikipedia.org/wiki/Lift-to-drag_ratio
The Shuttle is pretty close to the practical limit on speed and precision. It landed at just over 200mph, but it weighed about 100 tons. The X-37 appears to have had a much lower touchdown speed, though I'd be interested to know if anyone has the exact figures. 

it's certainly possible to land a vehicle with no wings in a simulation or in perfect weather, but to do so in real winds will be to take a risk that I don't think anyone who flew the Shuttle would welcome. Most of the lifting body tests were done at weights far below that of a returning spacecraft. The evolution of lifting bodies was a quest for better L/D that led from the from the rounded bottoms of the up to the X-24A to the flat-bottomed double-delta of the X-24B. This led to the conventional delta wing and fuselage of the Shuttle. Wings increase lift over a flattened body because thin lifting airfoils with higher aspect ratio produce more lift and less drag. The X-37 has so much lift it would have been difficult to drop it from a B-52:
http://www.spaceref.com/news/viewnews.html?id=823

Wings and fuselage do such different jobs it is difficult to design one shape that does both well. A fuselage with a non-circular cross-section has lower volumetric efficiency and is much more difficult to pressurize due to bending moments induced by internal pressure.

Second, the X-37 design was based on lessons learned from the shuttle. For example, one of the problems with the Shuttle was the limited pitch control authority due to the short coupling between the elevons and CG. This also made it quite sensitive to CG location. See pg 164 in the Shuttle document below:
http://klabs.org/DEI/Processor/shuttle/shuttle_tech_conf/1985008580.pdf

The X-37 retained the delta wing of the Shuttle, with its soft transition from hypersonic flight at high angle of attack to gliding flight, but put it amidships with separated tail surfaces and wing flaps to give much better control of pitch, trim, and lift.

[beancounter]

What are the feelings about X-37C vs DreamChaser?

Sounds like a new thread.

Why?  This is what confuses me so about "advocates" and/or the "space community".  What do "feelings" have to do with any of it?

First "we" are told that there IS a market.  That competition is good and the market will decide (implying we should WANT more possible vehicles).  In the next breath, there is seemingly only room for so many and no "others" are welcome and "commercial" must be a choice essentially between Boeing, SpaceX, Sierra Nevada and Blue Origin and only the designs that are known thus far which culminate in "versus" threads. 

It's odd to me personally but at the same time "I" am told by the "advocates" that "I" am supposed to take at face value that 10,000 jobs will be created, that SLS is a failure and pork, that SpaceX is the end-all and be-all (even though Falcon has launched only twice and it was not perfect), that more government money MUST be given to commercial, etc, etc, etc.

Just a little venting......

Perhaps instead of simply 'venting', you could consider doing some research into the various topics.  Then perhaps you could decide for yourself rather than basing it on what you are 'told'.  Just some friendly advice.  Take it or leave, the choice is your's.

[wolfpack]

I would guess a lifting body is also unneeded BEO.

More importantly, not possible from BEO. The reentry speeds and angles don't lend themselves to a gliding reentry. Unless you wanted to expend extra propellant needed to get yourself inserted back into a circularized LEO upon return from BEO, which is just plain silly. Better to design the spacecraft and TPS to take the heat of a ballistic reentry. And that's called a capsule.

[douglas100]

More importantly, not possible from BEO. The reentry speeds and angles don't lend themselves to a gliding reentry.

Is that actually the case? Can you cite evidence for that?

Don't get me wrong, I fully agree that for returning from BEO a capsule is  the right way to go. I just wondered what the show stopper for a winged shape would be.

[BrightLight]

More importantly, not possible from BEO. The reentry speeds and angles don't lend themselves to a gliding reentry.

Is that actually the case? Can you cite evidence for that?

Don't get me wrong, I fully agree that for returning from BEO a capsule is  the right way to go. I just wondered what the show stopper for a winged shape would be.

More arm waving - I remeber reading that the DC-XL could do BEO, that being said what does/did SNC intend for the "slipper" TPS - additional/thicker ablative coating? What does that do to the rentry flight profile?

[robert_d]

This I never quite understood. In principal, if you retain your environmental systems, would it not be possible to do an aerocapture into an Earth orbit with an orbital period that is long enough to dissipitate the initial heating and then either circularize for rendezvous or do a final reentry from there? 

More importantly, not possible from BEO. The reentry speeds and angles don't lend themselves to a gliding reentry. Unless you wanted to expend extra propellant needed to get yourself inserted back into a circularized LEO upon return from BEO, which is just plain silly. Better to design the spacecraft and TPS to take the heat of a ballistic reentry. And that's called a capsule.

[Lars_J]

It should be possible to aerocapture into a low earth orbit with one pass, but that would be A) very tricky maneuver and B) pick up a LOT of heat - how do you dissipate all of it?

[wolfpack]

Is that actually the case? Can you cite evidence for that?

Don't get me wrong, I fully agree that for returning from BEO a capsule is  the right way to go. I just wondered what the show stopper for a winged shape would be.

No, other than a conversation I had with some of the Orion engineers @ Dulles last April. They basically said wings are useless on the return trajectories that Orion would be flying.

I'm not well-versed in orbital mechanics, seeing as I'm an EE.

[douglas100]

OK. Thanks for that.

[mr. mark]

Everyone will eventually have to face the fact that at least near term winged vehicles are only going to be for LEO spaceflight. Capsules, as command modules, will have to handle the load as far as BEO goes.

[simonbp]

I would guess a lifting body is also unneeded BEO.

More importantly, not possible from BEO. The reentry speeds and angles don't lend themselves to a gliding reentry. Unless you wanted to expend extra propellant needed to get yourself inserted back into a circularized LEO upon return from BEO, which is just plain silly. Better to design the spacecraft and TPS to take the heat of a ballistic reentry. And that's called a capsule.

Not quite.

A "lifting body" is a vehicle that produces lift without wings. Apollo was (and Orion is) a lifting body because it reentered at a non-zero angle of attack, thus producing a small amount of lift in order to guide the vehicle's trajectory (in concert with the RCS). This in contrast to, say, the Mercury reentry vehicle, which ballistically reentered at zero angle of attack (and needed a naval task force to find it afterwards).

Winged vehicles, like Shuttle and X-37, are not suitable for high speed entry (>10 km/s) because the mechanical loads on the wings are just too high without having to resort to exotic materials. Also, the wings are very heavy for the amount of internal volume they offer.

Lifting bodies that work while subsonic (HL-10, X-24A, etc), on the other hand, have much less weight and volume penalty than winged vehicles, and can have much lower mass recovery systems than antisymmetric capsules (landing gear+aero surfaces vs. parachutes+rockets/airbags). So, it would be possible to design an optimized BEO lifting body, but it would not look anything like X-37...

[vulture4]

Dreamchaser has a much lower lift to drag ratio than X-37C. The L/D of the X-37 is about 4.5, the DC is at about 3.5, too low for a safe landing without powered lift.

Do you have citations or other data showing these L/D ratios? It is my impression that the DC lands un-powered as a glider?

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

This is an impressive piece of work, careful and meticulous, and worthy of a careful read. It explains what is known, and the level of uncertainty. You have to download it and read in acrobat; the preview doesn't show the figures quite properly. When I looked at Figure 3, I at first noticed the slow, painful struggle to improve lift and reduce drag through all the lifting bodies, and suborbital craft like the X-15. The Shuttle was slightly better than any of the wingless lifting bodies.

Then I noticed an outlier in Figure 3 that did not even seem part of the same group, and it struck me. The Shuttle, with its huge engine bells and OMS pods, was burdened by a totally unaerodynamic tail section that caused most of its drag, while the wingless lifting bodies all had streamlined tails. When the field was leveld by adding the Shuttle tail cone (still not particularly streamlined) the Shuttle, with traditional wings and fuselage, absolutely blows the doors off every wingless lifting body, past, present or future. In a field where an increase of 5% is a struggle, the L/D of the Shuttle with tailcone was about 7.5, twice that of the HL-10.

It's not rocket science. But it is basic aerodynamics, and we seem to have forgotten it. Wings need a thin airfoil optimized to generate lift with a reasonable aspect ratio to minimize induced drag. A fuselage needs a circular cross-section to maximize volume, minimize parasitic drag and eliminate bending loads when the cabin is pressurized.

The X-37 was based on the lessons of Shuttle; the delta wing had reasonable lift and a soft transition from high-alpha hypersonic entry to gliding flight. But the Shuttle was sensitive to CG because of the short moment arm available to the elevons and flap, and the body flap caused so much nose-down trim it could not be used as flaps normally are, to increase lift. The vertical tail was of no use during hypersonic entry because it was in the wake of the body. So with the X-37 the wing was kept as a delta but moved amidships, and a V-tail was added with each surface in the airstream and useful during entry, separated from the wing to give a longer moment arm and much better pitch control. The wings even got conventional flaps, useful now that they were farther forward. As an orbiter, it has only a small OMS engine aft; the tail is otherwise streamlined, so the L/D will be close to that of the orbiter with tailcone. The X-37 has so much lift it would have needed a drag chute to drop it from the NASA B-52. I would be surprised if it was much over 100 knots at touchdown. The next time you fly, ask the pilot whether it is safer to land an aircraft with a stall speed of 100 knots, or 200.

Yet none of these factors seem to have been considered in the commercial crew selection, which dropped OSC's wing-and-fuselage Prometheus in favor of the Dreamchaser. Looking at the selection criteria, it is hard to see anywhere actual aerodynamic preformance, and particularly safety margins in gliding flight, was even considered.

[sb]

I don't think anyone has ”forgotten” how aerodynamics works, it's just that high L/D isn't necessarily the be-all & end-all of spacecraft design. If you read the NASA history on lifting body research you'll see that actually while a certain minimum L/D was found necessary for a safe flare, the steep approach path of the lifting bodies at least wasn't disliked for precision approaches.

Which raises another point: you have to distinguish between L/Ds in different flight regimes. The sharp-edged lifting bodies were designed for improved hypersonic L/D & hence cross-range. Subsonic performance was only really of interest as to whether they could be landed safely.

[vulture4]

I agree that aerospace vehicle design is always a compromise, but for a design that works we should never give away an asset unless we get something more valuable. Capsules have low L/D (low crossrange in hypersonic entry, require parachute for landing) but gain volumetric and mass efficiency, structural simplicity, and, in theory, the ability to re-enter under manual control (the Soyuz ballistic mode). The parachute increases turnaround costs in a reusable system and is difficult to scale to large reusable vehicles landing on land like the shuttle, meaning reusability is less feasible.

Runway landing is the strategy used for almost all commercial aviation because it minimizes cost in reusable flight operations and permits almost unlimited scalability in size. If we see human spaceflight as ever being available on a large scale at an affordable price we need vast improvements in cost, and that was the rationale for runway landing for the Shuttle.

The Shuttle's landing performance was very close to the safe limits and had imposed inflexible weather limits. It required a 15,000 foot runway, a rare commodity, and very accurate weather prediction. There was no room for error. It is possible to operate under these conditions, but it is not something one does if there is an alternative. And, as I pointed out, given equal requirements for engines at the tail the Shuttle is vastly superior to any lifting body. The Shuttle also has greater hypersonic crossrange than a wingless design. It's quite true the extremely sharp-edged waverider concept has even higher L/D at hypersonic speed, but it sacrifices a lot of cargo volume for a given dry mass.

The question I keep asking is, what do we gain by eliminating the wings? A wingless lifting body that is even marginally capable of runway landing has a flattened fuselage with more hull per unit volume than a round fuselage, and more weight if it is pressurized due to the need for internal bracing and bending moments in the hull. The original rationale for the lifting body was to avoid sharp leading edges, and the development of high-temperature composites for this purpose was one of the reasons the Shuttle went back to wings. No commercial aircraft flies without wings because even though it is just barely possible, it adds cost and risk and provides no benefits. The few aircraft, like the B-2, that do not have both wings and fuselage give up the fuselage, not the wings.

That's why a direct comparison of the X-37 and Dreamchaser would be so revealing. Does anybody know how fast it was going at touchdown?

[Rocket Science]

190kts...

[vulture4]

Interesting. Faster than I would have guessed.

[BrightLight]

Interesting. Faster than I would have guessed.

The X-37C is stated to be 48 feet long as compared to the X-37B which is 29 feet long. The X-37B is about 11,000 lbs
Scaling Law:
"When a physical object maintains the same density and is scaled up, its mass is increased by the cube of the multiplier "
The ratio 48 to 29 feet is 1.65
following the mass scaling law, the multiplier is 4.53,
the scaled mass is 11,000 * 4.53 or almost 50,000lbs!
The DC is roughly 30,000 lbs and lands somewhere between 190 and 200 knots.  The caveat here is maintaining the same density, as I am not a aeronautical engineer (arm waving) I can't define this but I assume that the density will be lower on the X-37C when compared to the B model and the mass will be less than 50,000 lbs loaded.

[Lars_J]

I'm certainly looking forward to the DC drop tests - we should get a wealth of new information to debate.

[vulture4]

It is odd no attempt was made to streamline the tail of the X-37, since it has only one small, centrally mounted OMS nozzle. That square tail adds a lot of drag, maybe 30% or more of the total.

It would be interesting to know the weight for the DC drop tests; will it be the planned operational gross weight of somewhere between 9 and 11 metric tons? Most of the testing of older lifting body designs was done at much lower vehicle mass. I.e. X-24A about 3 metric tons at landing (3.8 for the X-34B).

[Rocket Science]

Interesting. Faster than I would have guessed.

You might want to re-visit as to what you define as “faster” as I answered you in the Q&A thread… So I’ll link it to you again…

http://forum.nasaspaceflight.com/index.php?topic=29126.15

[vulture4]

An interesting document. I am curious why DOD dropped the project as a NASA partner, why NASA then dropped it, and why DOD then picked up the entire project it had previously dropped. Despite the two missions it isn't clear whether it is "operational" in its current form or a development prototype for something else, as it was under NASA. In recent years DOD has expressed interest in fully reusable launch systems, and particularly flyback booster stages, as Jay Penn described:

http://www.nasa.gov/centers/kennedy/news/beyondnextgen.html

Perhaps the X-37 is part of a program to develop a reusable upper stage for such an RLV.

[Prober]

Interesting. Faster than I would have guessed.

The X-37C is stated to be 48 feet long as compared to the X-37B which is 29 feet long. The X-37B is about 11,000 lbs
Scaling Law:
"When a physical object maintains the same density and is scaled up, its mass is increased by the cube of the multiplier "
The ratio 48 to 29 feet is 1.65
following the mass scaling law, the multiplier is 4.53,
the scaled mass is 11,000 * 4.53 or almost 50,000lbs!
The DC is roughly 30,000 lbs and lands somewhere between 190 and 200 knots.  The caveat here is maintaining the same density, as I am not a aeronautical engineer (arm waving) I can't define this but I assume that the density will be lower on the X-37C when compared to the B model and the mass will be less than 50,000 lbs loaded.

Need to keep in mind the X-37B is a "test" model.
Your numbers are off.

[BrightLight]

Interesting. Faster than I would have guessed.

The X-37C is stated to be 48 feet long as compared to the X-37B which is 29 feet long. The X-37B is about 11,000 lbs
Scaling Law:
"When a physical object maintains the same density and is scaled up, its mass is increased by the cube of the multiplier "
The ratio 48 to 29 feet is 1.65
following the mass scaling law, the multiplier is 4.53,
the scaled mass is 11,000 * 4.53 or almost 50,000lbs!
The DC is roughly 30,000 lbs and lands somewhere between 190 and 200 knots.  The caveat here is maintaining the same density, as I am not a aeronautical engineer (arm waving) I can't define this but I assume that the density will be lower on the X-37C when compared to the B model and the mass will be less than 50,000 lbs loaded.

Need to keep in mind the X-37B is a "test" model.
Your numbers are off.

I realize that the X stands for experimental. The exercise was to demonstrate that it's not as simple to scale a spacecraft, what numbers are wrong? What is the mass of the x-37C? How does one scale a body?

[vulture4]

Interesting. Faster than I would have guessed.

The X-37C is stated to be 48 feet long as compared to the X-37B which is 29 feet long. The X-37B is about 11,000 lbs
Scaling Law:
"When a physical object maintains the same density and is scaled up, its mass is increased by the cube of the multiplier "
The ratio 48 to 29 feet is 1.65
following the mass scaling law, the multiplier is 4.53,
the scaled mass is 11,000 * 4.53 or almost 50,000lbs!
The DC is roughly 30,000 lbs and lands somewhere between 190 and 200 knots.  The caveat here is maintaining the same density, as I am not a aeronautical engineer (arm waving) I can't define this but I assume that the density will be lower on the X-37C when compared to the B model and the mass will be less than 50,000 lbs loaded.

Need to keep in mind the X-37B is a "test" model.
Your numbers are off.

I realize that the X stands for experimental. The exercise was to demonstrate that it's not as simple to scale a spacecraft, what numbers are wrong? What is the mass of the x-37C? How does one scale a body?

It's just a rough approximation, an accurate estimate would take more detail. If scaled up to the size of the Shuttle (x4 in length) multiplying by 4^3 would give you about 300 metric tons, three times the actual Orbiter mass.

[Rocket Science]

The flaw in scaling is assuming a constant mass/volume ratio. In the case of Shuttle you would have a high M/V in the fore (cabin, RCS) and in the aft (engines, tanks). The center 60’ cargo bay would be relatively a low M/V and via a high percentage of overall dimension thus a source of error… Just for you to consider… Carry on

[vulture4]

The flaw in scaling is assuming a constant mass/volume ratio. In the case of Shuttle you would have a high M/V in the fore (cabin, RCS) and in the aft (engines, tanks). The center 60’ cargo bay would be relatively a low M/V and via a high percentage of overall dimension thus a source of error… Just for you to consider… Carry on

I'm  unclear as to whether the X-37 mass was with fuel. It seems to have a higher propellant mass fraction than the Shuttle Orbiter, though it's hard to tell what changes DOD made when they switched to hypergols. There is a Shuttle-like payload bay but it is relatively small.

Here's a review of a presentation by Arthur Grantz of Boeing that has some detailed drawings of the proposed "C" model. Maybe they left the stern flat because they planned to put the APAS there.

http://www.space.com/13230-secretive-37b-space-plane-future-astronauts.html

[Rocket Science]

The flaw in scaling is assuming a constant mass/volume ratio. In the case of Shuttle you would have a high M/V in the fore (cabin, RCS) and in the aft (engines, tanks). The center 60’ cargo bay would be relatively a low M/V and via a high percentage of overall dimension thus a source of error… Just for you to consider… Carry on

I'm  unclear as to whether the X-37 mass was with fuel. It seems to have a higher propellant mass fraction than the Shuttle Orbiter, though it's hard to tell what changes DOD made when they switched to hypergols. There is a Shuttle-like payload bay but it is relatively small.

Here's a review of a presentation by Arthur Grantz of Boeing that has some detailed drawings of the proposed "C" model. Maybe they left the stern flat because they planned to put the APAS there.

http://www.space.com/13230-secretive-37b-space-plane-future-astronauts.html

Yes, by the nature of the vehicle’s mission much is not known and all speculation. What we can discern is that in terms of overall M/V for the x-37, is that it is more evenly distributed throughout the craft relative to the Shuttle by nature of its short “close coupled” length, CoL (wings) and Cg. Note gear placement for example and compare it to the obiter.

In an exercise for my physics students we compared a modern day reptiles/raptors mass using a scaling-up to the size of a dinosaur like T-Rex for  example,  that the final weight of the animal would shatter its limbs under its own forces if it tried to run, if we limit the legs to what we see in the fossil record. I did this for them to exercise caution when trying to scale-up and its potential source of errors…

[Prober]

The flaw in scaling is assuming a constant mass/volume ratio. In the case of Shuttle you would have a high M/V in the fore (cabin, RCS) and in the aft (engines, tanks). The center 60’ cargo bay would be relatively a low M/V and via a high percentage of overall dimension thus a source of error… Just for you to consider… Carry on

or the easy way is to see how they scaled the x-40 to the x-37B.  A good hint for you.

[Rocket Science]

The flaw in scaling is assuming a constant mass/volume ratio. In the case of Shuttle you would have a high M/V in the fore (cabin, RCS) and in the aft (engines, tanks). The center 60’ cargo bay would be relatively a low M/V and via a high percentage of overall dimension thus a source of error… Just for you to consider… Carry on

or the easy way is to see how they scaled the x-40 to the x-37B.  A good hint for you.

Yes, but that was not much of a leap...

[vulture4]

It appears that Boeing at least informally promoted a manned version of the X-37C in 2011, showing crew and APAS. I assume this was intended for civilian access to the ISS since if it were a DOD project it would presumably have been classified. Boeing apparently designated the Atlas as LV for the X-37C, so that sets an upper limit of about 20.5 metric tons even if the heaviest version (552) was used. http://en.wikipedia.org/wiki/Boeing_X-37

[BrightLight]

It appears that Boeing at least informally promoted a manned version of the X-37C in 2011, showing crew and APAS. I assume this was intended for civilian access to the ISS since if it were a DOD project it would presumably have been classified. Boeing apparently designated the Atlas as LV for the X-37C, so that sets an upper limit of about 20.5 metric tons even if the heaviest version (552) was used. http://en.wikipedia.org/wiki/Boeing_X-37

Since the Atlas was  declared as the LV - I think you nailed it with a upper limit on mass (My gut tells me it will be more like 30K lbs - pure arm waiving).  However, DOD (Air Force) has wanted man-in-the-loop for quite some time, since the days of the X-15 and X-20. The Air Force has a penchant for wings (X planes), so why not a DOD version of the HL-20/DC.  What is special about the X-37 form?

[Go4TLI]

The crewed version of the X-37 is not going to happen, as much as folks like to speculate  The Boeing proposal is the CST-100.

[clongton]

What is special about the X-37 form?

Wings. They're more efficient than a lifting body for cross range and stall speed.

[JBF]

What is special about the X-37 form?

Wings. They're more efficient than a lifting body for cross range and stall speed.

Which you only need for military and/or emergency situations. In all other situations they are a waste of mass.

[Patchouli]

The crewed version of the X-37 is not going to happen, as much as folks like to speculate  The Boeing proposal is the CST-100.

It could be a follow on to the CST-100 if it's successful.

Of course the X-37C could end up being mostly a robotic space plane or a vehicle tailored for military needs.

[clongton]

What is special about the X-37 form?

Wings. They're more efficient than a lifting body for cross range and stall speed.

Which you only need for military and/or emergency situations. In all other situations they are a waste of mass.

I didn't say they were better. I just answered the question:"What is special about the X-37 form?"
The general issue is "wings or lifting body?" Each has their own advantage.
That's the advantage wings has and that's the question that was asked.

[BrightLight]

The manned version of the X-37, the C model has some odd flavors to it - why 6 people, that sounds like an ISS need, yet the X-37 is a Air force/DOD program.  If the DOD wanted a manned, reusable, winged spacecraft why so many people? to have a all American DOD mission to ISS would be problematic with the Russians.  If Boeing were going to offer it as a CCDev solution what would the CST-100 become.  Unless the DOD has a program for manned missions, I am coming to to the conclusion that the X-37C manned version is a PR issue.

[Jim]

The manned version of the X-37, the C model has some odd flavors to it - why 6 people, that sounds like an ISS need, yet the X-37 is a Air force/DOD program.

No, can't make that comparison.  X-37 was originally a NASA program.  NASA dropped it and the DOD took it over. The DOD does not own the "legacy" of the program, X-37C is a Boeing commercial development and has no DOD influences.

[Prober]

The manned version of the X-37, the C model has some odd flavors to it - why 6 people, that sounds like an ISS need, yet the X-37 is a Air force/DOD program.

No, can't make that comparison.  X-37 was originally a NASA program.  NASA dropped it and the DOD took it over. The DOD does not own the "legacy" of the program, X-37C is a Boeing commercial development and has no DOD influences.

A well written answer.

[vulture4]

DOD (Air Force) has wanted man-in-the-loop for quite some time, since the days of the X-15 and X-20.

I agree, but that may be changing as more drones were procured last year than manned aircraft.

The Air Force has a penchant for wings (X planes), so why not a DOD version of the HL-20/DC.  What is special about the X-37 form?

Could it be because the DC doesn't HAVE wings?

The DC and X-37 bear a superficial resemblance, and both have been referred to loosely as "lifting bodies", as distinct from capsules. But they stem from different lines of thought and are totally different aerodynamic concepts.

The DC is based on the Soviet BOR-4 subscale prototype, but it stems culturally from the attempts of the 60's to build an airplane without wings. This began because it was felt (by NASA) that no material could tolerate the high temperature imposed on sharp leading edges by the hypersonic airflow during atmospheric entry. So it seemed natural, in an era when the impossible took only a little longer, to design an aircraft that did not need them. The downside was that lift-to-drag ratio (L/D) was marginal. Paradoxically the Dyna-Soar, an Air Force project that began before Mercury, had conventional wings and fuselage, and ultimately advances in materials made the Shuttle possible with its conventional delta wing and a L/D which was, except for the drag of the huge engine nozzles at the tail, exactly twice that of the HL-10. The X-37 was an evolution of the Shuttle design, with conventional delta wings, but with a separated V-tail added to improve control of pitch and CG tolerance.

So, in retrospect, the military has favored wings and NASA has not.This is a matter on which there is some disagreement, and I want to stress that I have great respect for other viewpoints. But we cannot forget history, or basic aerodynamics. Wings and fuselage do such different tasks that it is, in my opinion, impossible for one structure to do both tasks well.

[Jim]

However, DOD (Air Force) has wanted man-in-the-loop for quite some time, since the days of the X-15 and X-20.

And repeatedly has found that there is no benefit to it.

[mmeijeri]

And repeatedly has found that there is no benefit to it.

Besides, man in the loop doesn't mean man on board, compare drones for instance.

[vulture4]

And repeatedly has found that there is no benefit to it.

Besides, man in the loop doesn't mean man on board, compare drones for instance.

Alternatively, with the autonomous landing system they have just demonstrated, man on board doesn't necessarily mean man in the loop.

[Lars_J]

And repeatedly has found that there is no benefit to it.

Besides, man in the loop doesn't mean man on board, compare drones for instance.

Alternatively, with the autonomous landing system they have just demonstrated, man on board doesn't necessarily mean man in the loop.

Shhhhh! Don't tell the pilot wing of the Astronaut corps! 

[Star One]

And repeatedly has found that there is no benefit to it.

Besides, man in the loop doesn't mean man on board, compare drones for instance.

Alternatively, with the autonomous landing system they have just demonstrated, man on board doesn't necessarily mean man in the loop.

I wonder how much human input it has whilst on orbit as far as controlling it day to day is concerned or does it do most of the mundane stuff itself.

[Jim]

I wonder how much human input it has whilst on orbit as far as controlling it day to day is concerned or does it do most of the mundane stuff itself.

Most spacecraft are autonomous for day to day type operations

[vulture4]

I wonder how much human input it has whilst on orbit as far as controlling it day to day is concerned or does it do most of the mundane stuff itself.

Most spacecraft are autonomous for day to day type operations

Several press releases have said the landing was "autonomous" rather than remotely piloted.

[vulture4]

Even though it is unlikely this will ever come to be it would be a great addition to ISS. It will give us a way to bring up ORUs previously only the shuttle could bring up.

This, in my opinion, is the single biggest advantage of X-37 to ISS, since this is a unique capability that only the X-37 can offer.

Everyone misses the real “asset” of the x37b program.    It’s further along, tested, and it works!   That’s the real excitement here.   

NASA could have a real winner here and doesn’t really know it.  Right now I would love to see NASA work with USAF on this. Given the specs of the X37 run a test to fly to the ISS (no birthing) and after sometime return.     

This is a “mission change” for the test program, but could be well worth it in the future.  The Original design specs might have changed.   Some of the published x37b specs have an uber high orbit (much higher than the ISS).

I absolutely agree, but on the NASA side it is hard to find anyone who even understands the difference between the X-37C (a wing-and-fuselage design) and the Dreamchaser (a lifting body).

[vulture4]

190kts...

Could that be because the wings were constrained to a span of less than 15 feet by the need to fit in the Shuttle cargo bay? Did the X-37C maintain the same wing loading? The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

[Prober]

190kts...

The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

the squared off tail comes back in the x-40 days...
designed for the shuttle, then delta II, then moved to Atlas.
this program(s) go in many directions to keep funded.

[Jim]

the squared off tail comes back in the x-40 days...
designed for the shuttle, then delta II, then moved to Atlas.
this program(s) go in many directions to keep funded.

 the design did not change in going from shuttle to ELV's.  Delta II was only considered for a few months.

[Jim]

Could that be because the wings were constrained to a span of less than 15 feet by the need to fit in the Shuttle cargo bay?

yes.

[Rocket Science]

190kts...

Could that be because the wings were constrained to a span of less than 15 feet by the need to fit in the Shuttle cargo bay? Did the X-37C maintain the same wing loading? The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

The first thing we have to remember is that this is a rocket plane and not an airplane. That being said, the square -off back end you refer to can be seen on all the "X Series: of rocket planes that had engine bells an feed/dump lines at the rear. The obvious other reason is that you have to mate your rocket plane to the adapter on the launch vehicle. Other vehicles like the Shuttle had to deal with base heating from all the engines and motors back there.
It is not a big deal to have a squared off tail and you see it daily on road vehicles every day and on the racetrack for purposedly designed sports racing cars. The Kammback was a result of aerdynamic theory of Von Karman. He found that there are a subset of design conditions (particularly when there is a length constraint involved) where the total drag is less if you simply cut off the tailcone with sharp corners, rather than taper it down to a point in the same overall length, with attendant massive flow detachment. We don't see that used in airplanes much because we rarely have a length constraint of that magnitude.

http://www.centennialofflight.gov/essay/Theories_of_Flight/von_Karman/TH21.htm

[vulture4]

190kts...

The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

the squared off tail comes back in the x-40 days...
designed for the shuttle, then delta II, then moved to Atlas.
this program(s) go in many directions to keep funded.

The fact that it has survived this long and not simply faded away suggests that there is somebody (I assume at Boeing) who has a clear vision of the advantages of the concept and the role it could play. I would think without the fairing a somewhat longer wing and a mating structure on the booster that would allow the tail of the flight vehicle to be a little more streamlined could really improve landing performance in marginal winds.

NASA seems to see little or no difference between the winged X-37 and a  wingless lifting body, which seems ironic considering the close relationship of the X-37 to the Shuttle design and the research during the design phase of the Shuttle program years ago. To me the delta wing and separated V-tail configuration of the X-37 would appear to have better potential for hypersonic crossrange (due to the wing area at high angle of attack) providing more landing opportunities, CG tolerance (due to the long moment arm for pitch trim) and better structural weight and fatigue life (due to the feasibility of a circular pressure hull). Most importantly, the low-speed L/D and should be higher, providing lower touchdown airspeed and improvement in the landing weather requirements (due to the higher aspect ratio of the lifting airfoil). The X-37 even has wing flaps, not feasible on the Shuttle or Dreamchaser. The Shuttle landings had significant constraints on weather, CG etc. and were on occasion near the edge of what could be safely accomplished; wider performance margins on landing would, in my opinion, significantly improve both safety and operational flexibility.

[Rocket Science]

With all due respect, your opinion doesn’t trump aerodynamics and operational requirements. I have already posted to you more once that the X-37 landing speed is >200Kts with reference link. No matter how much you like the X-37 accept the laws of aero-physical laws and move on… I should know, I teach physics and I’m also licensed pilot and auto racer…

Regards
Robert

[vulture4]

With all due respect, your opinion doesn’t trump aerodynamics an operational requirements. I have already posted to you more once that the X-37 landing speed is >200Kts with reference link. No matter how much you like the X-37 accept the laws of aero-physical laws and move on… I should know, I teach physics and I’m also licensed pilot and auto racer…

Regards
Robert

I replied that the X-37 wingspan and aspect ratio was constrained by the need to fit in the 15 foot payload bay of the Shuttle.

I am not a race car driver, but it is my understanding that the goal of a race car is to _avoid_ aerodynamic lift. At least that seemed to be the purpose of the reverse-ground-effect vacuum blowers that Porsche used to run in the Can-Am at Watkins Glen before they were disallowed. The goal of an aircraft (I got my pilot's license 40 year ago and have two engineering degrees and 25 years in the space program) is in most circumstances to improve lift and reduce drag. I would hope you would take the time to actually read the paper on aerodynamic performance of the lifting bodies for which I provided a link.

"It is not a big deal to have a squared off tail"

That of course depends on whether or not drag is a concern. Most of the NASA lifting bodies had extensive boattailing yet managed L/D no more than 3.5. The wing-and-fuselage Shuttle did better than any of them with 4.5 even with the engine bells exposed. The importance of tail drag is clearly demonstrated by the performance of the Shuttle with the tail fairing in place; it has an L/D of 7.5, exactly double that of the HL-10 and blowing the doors off any of the lifting body designs. This kind of performance advantage is extraordinary and cannot, in my opinion, be ignored if we want a launch system that is practical and safe.

[Rocket Science]

With all due respect, your opinion doesn’t trump aerodynamics an operational requirements. I have already posted to you more once that the X-37 landing speed is >200Kts with reference link. No matter how much you like the X-37 accept the laws of aero-physical laws and move on… I should know, I teach physics and I’m also licensed pilot and auto racer…

Regards
Robert

I replied that the X-37 wingspan and aspect ratio was constrained by the need to fit in the 15 foot payload bay of the Shuttle.

I am not a race car driver, but it is my understanding that the goal of a race car is to _avoid_ aerodynamic lift. At least that seemed to be the purpose of the reverse-ground-effect vacuum blowers that Porsche used to run in the Can-Am at Watkins Glen before they were disallowed. The goal of an aircraft (I got my pilot's license 40 year ago and have two engineering degrees and 25 years in the space program) is in most circumstances to improve lift and reduce drag. I would hope you would take the time to actually read the paper on aerodynamic performance of the lifting bodies for which I provided a link.

"It is not a big deal to have a squared off tail"

That of course depends on whether or not drag is a concern. Most of the NASA lifting bodies had extensive boattailing yet managed L/D no more than 3.5. The wing-and-fuselage Shuttle did better than any of them with 4.5 even with the engine bells exposed. The importance of tail drag is clearly demonstrated by the performance of the Shuttle with the tail fairing in place; it has an L/D of 7.5, exactly double that of the HL-10 and blowing the doors off any of the lifting body designs. This kind of performance advantage is extraordinary and cannot, in my opinion, be ignored if we want a launch system that is practical and safe.

A purpose designed racer had to reduce drag while creating downforce. I’ve read those paper yet you still refuse to believe that the x-37 has a high wing loading and still will have cross wind limitations. It is not a glider sailplane with a 50:1 glide ratio…

Edit to add: If you re-read that paper you can see the “tail cone” on the Orbiter was used only for the early ALT’s and not the operational Orbiter retuning to Earth. It was later removed for proper data collection and flight handling. Thus that represents the realistic lower L/D ratio. All the lifting bodies had a “chopped” flat tail area and made use of the laminar flow being maintained at the rear. Unless you have an extremely long vehicle like Concorde, can you maintain laminar flow at the rear with your “boat tail”. For all the “blunt-short” lifting entry bodies like including Dream Chaser and X-37 (winged or not) the Von Karman “Kammback” is effective for an operational compromise. Now if you are going to ferry a vehicle like the Orbiter on the SCA, of course the tail cone will reduce drag and fuel consumption and increased airspeed

[vulture4]

I agree the X-37 has a high wing loading, the result of the need to fit in the orbiter payload bay. The C model would not have this constraint.

Here's an interesting video-
http://www.space.com/9940-secretive-space-plane-meet-37b.html
from this page
http://www.space.com/13230-secretive-37b-space-plane-future-astronauts.html

[Rocket Science]

I agree the X-37 has a high wing loading, the result of the need to fit in the orbiter payload bay. The C model would not have this constraint.

Here's an interesting video-
http://www.space.com/9940-secretive-space-plane-meet-37b.html
from this page
http://www.space.com/13230-secretive-37b-space-plane-future-astronauts.html

It really no longer has to just do with the payload bay of the orbiter. One the DoD took it over they could have done what they wanted with it including increase wingspan and better glide ratio. They chose not to because of operational requirements, launch fairing and entry heat load on them, thus a compromise as all engineering solutions are.
If you recall the early Shuttle designs there was a battle of wills  (Max Faget) over long non-swept wing vs delta wings. The double-delta with chines won out and still was a compromise…
If Boeing thinks the X-37C is better than their CST-100 they would built it. So I challenge you to convince them .
http://www.astronautix.com/lvs/shuenara.htm

[vulture4]

The DOD elected not to change the aerostructure although they backtracked to hypergols on propulsion. Since the original design had not included aero loads on launch they had to fabricate a 5-meter fairing for the Atlas to duplicate the orbiter payload bay. It was quite a sight on the first launch with the big fairing dropping off in four segments just as the rocket cleared the earth's shadow. This was considered easier than changing the aerostructure.

[Rocket Science]

The DOD elected not to change the aerostructure although they backtracked to hypergols on propulsion. Since the original design had not included aero loads on launch they had to fabricate a 5-meter fairing for the Atlas to duplicate the orbiter payload bay. It was quite a sight on the first launch with the big fairing dropping off in four segments just as the rocket cleared the earth's shadow. This was considered easier than changing the aerostructure.

Hypergolics are simple, easy to store and perfect for long duration flights...

[Jim]

The DOD elected not to change the aerostructure although they backtracked to hypergols on propulsion. Since the original design had not included aero loads on launch they had to fabricate a 5-meter fairing for the Atlas to duplicate the orbiter payload bay. It was quite a sight on the first launch with the big fairing dropping off in four segments just as the rocket cleared the earth's shadow. This was considered easier than changing the aerostructure.

It wasn't a specially made fairing, it was a stock 5 meter.  And it was two piece, the second set of pieces were from the CFLR deck.

[Jim]

It really no longer has to just do with the payload bay of the orbiter.
 One the DoD took it over they could have done what they wanted with it including increase wingspan and better glide ratio.

Yes, it did since Titan IV and subsequently EELV fairings were sized to shuttle bay. Not true, design was basically complete and some hardware ordered and built when the DOD took over.

[Rocket Science]

It really no longer has to just do with the payload bay of the orbiter.
 One the DoD took it over they could have done what they wanted with it including increase wingspan and better glide ratio.

Yes, it did since Titan IV and subsequently EELV fairings were sized to shuttle bay. Not true, design was basically complete and some hardware ordered and built when the DOD took over.

Yes Jim, all true. My only point is if it "were" needed they could evolve the design, but she flys fine as is...

[Prober]

The DOD elected not to change the aerostructure although they backtracked to hypergols on propulsion. Since the original design had not included aero loads on launch they had to fabricate a 5-meter fairing for the Atlas to duplicate the orbiter payload bay. It was quite a sight on the first launch with the big fairing dropping off in four segments just as the rocket cleared the earth's shadow. This was considered easier than changing the aerostructure.

the DOD did a mission change.   I have a great deal of research and the project had many conflicts during its development.  The AR2-3 engine was redesigned and tested at Stennis.  Mission was for like 21-27 days with a landing.

This pic during the build you might find interesting.

[Jim]

the DOD did a mission change.   I have a great deal of research and the project had many conflicts during its development.  The AR2-3 engine was redesigned and tested at Stennis.  Mission was for like 21-27 days with a landing.

No, those changes happened while it was under NASA, long before DOD took over.

[Prober]

190kts...

Could that be because the wings were constrained to a span of less than 15 feet by the need to fit in the Shuttle cargo bay? Did the X-37C maintain the same wing loading? The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

and this you will enjoy.....one of the subprojects proposed.

http://www.sei.aero/eng/papers/uploads/archive/AIAA-2004-5950.pdf

[BrightLight]

190kts...

Could that be because the wings were constrained to a span of less than 15 feet by the need to fit in the Shuttle cargo bay? Did the X-37C maintain the same wing loading? The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

and this you will enjoy.....one of the subprojects proposed.

http://www.sei.aero/eng/papers/uploads/archive/AIAA-2004-5950.pdf

How much is that pony in the window?

[Rocket Science]

190kts...

Could that be because the wings were constrained to a span of less than 15 feet by the need to fit in the Shuttle cargo bay? Did the X-37C maintain the same wing loading? The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

and this you will enjoy.....one of the subprojects proposed.

http://www.sei.aero/eng/papers/uploads/archive/AIAA-2004-5950.pdf

How much is that pony in the window?

To quote Carl Sagan… “Billions and billions”…

[Lars_J]

190kts...

Could that be because the wings were constrained to a span of less than 15 feet by the need to fit in the Shuttle cargo bay? Did the X-37C maintain the same wing loading? The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

and this you will enjoy.....one of the subprojects proposed.

http://www.sei.aero/eng/papers/uploads/archive/AIAA-2004-5950.pdf

Aww, how cute, the little cousin of the X-30. Scramjet dreams die hard.

[RanulfC]

190kts...

Could that be because the wings were constrained to a span of less than 15 feet by the need to fit in the Shuttle cargo bay? Did the X-37C maintain the same wing loading? The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

and this you will enjoy.....one of the subprojects proposed.

http://www.sei.aero/eng/papers/uploads/archive/AIAA-2004-5950.pdf

Aww, how cute, the little cousin of the X-30. Scramjet dreams die hard.

By far not the ONLY one which used a "generic" X-37 spaceplane payload. See also:
http://www.sei.aero/eng/papers/uploads/archive/SEI_JANNAF_Sentinel_2007.pdf

http://www.sei.aero/eng/papers/uploads/archive/SEI_JANNAF_Sentinel_2007_present.pdf

In fact a lot of the early "SUSTAIN" artwork showed a "generic" DC-Y like "booster" with a small "X-37-ish" spaceplane in a side mounted position.

Randy

[vulture4]

To be launched, the paper says, from the "Cape Canaveral Military Spaceport". Interesting.

[Rocket Science]

190kts...

Could that be because the wings were constrained to a span of less than 15 feet by the need to fit in the Shuttle cargo bay? Did the X-37C maintain the same wing loading? The other asre that puzzles me is the squared-off tail of the X-37B. The final design had to fit inside a 5m fairing and also be mounted to the Atlas by the tail for launch, maybe the square (and high-drag) tail was needed for the latter.

and this you will enjoy.....one of the subprojects proposed.

http://www.sei.aero/eng/papers/uploads/archive/AIAA-2004-5950.pdf

Aww, how cute, the little cousin of the X-30. Scramjet dreams die hard.

By far not the ONLY one which used a "generic" X-37 spaceplane payload. See also:
http://www.sei.aero/eng/papers/uploads/archive/SEI_JANNAF_Sentinel_2007.pdf

http://www.sei.aero/eng/papers/uploads/archive/SEI_JANNAF_Sentinel_2007_present.pdf

In fact a lot of the early "SUSTAIN" artwork showed a "generic" DC-Y like "booster" with a small "X-37-ish" spaceplane in a side mounted position.

Randy

It is a great overall design that works Randy and you know how I feel that it could be used as a flyback booster if scaled up…
~Robert

[vulture4]

The DOD is very interested in and is actually funding serious work in reusable booster stage development. Convenient, since they already have the X-37. It is too bad NASA does not seem interested.
http://www.nasa.gov/centers/kennedy/news/beyondnextgen.html