The X-37B: Exploring expanded capabilities for ISS missions

[Chris Bergin]

http://www.nasaspaceflight.com/2013/03/x-37b-expanded-capabilities-iss-missions/

Excellent article by Chris Gebhardt based on a presentation acquired by L2.

Don't get overexcited, it's a review of options that did not go forward (for all we know).

[vulture4]

However there is talk about landing the X-37 at KSC and refurbishing it there as well. X37B has performed remarkably well, but unfortunately lacks an obvious DOD mission and it isn't clear DOD would consider a larger followon.

IMHO X-37C would have significant advantages over DC with a higher lift to drag ratio during approach and a lower touchdown speed, making the whole landing process a bit safer. In contrast DC seems to descend more steeply than Shuttle. The big disadvantage the X-37C had in the manned flight competition was that because of the narrow fuselage it was impossible for the crew to sit side by side in the front as they can with the DC, and even providing a windshield for one pilot was difficult. Of course the X-37 doesn't need any windshield; it can land flawlessly on autopilot and it would be much more efficient to provide video for piloting as a backup, but that isn't an easy sell.

[Lars_J]

Of course the X-37 doesn't need any windshield; it can land flawlessly on autopilot and it would be much more efficient to provide video for piloting as a backup, but that isn't an easy sell.

Now we couldn't deny the pilot wing of the Astronaut corps the oppertunity to stare out a windshield, now could we? 

[Rocket Science]

Enjoyable read Chris G!  Always great to see potential options for a spacecraft....

[vt_hokie]

Man, would I be rooting for Boeing big time if they had gone this route over CST-100.  As it is, Dream Chaser all the way!

[yg1968]

As NASA and its new commercial partners continue to push toward the era of realized commercial crew transportation to Low Earth Orbit (LEO), Boeing has released a paper detailing the potentiality of expanding the capabilities of the U.S. Air Force’s X-37B reusable space plane for cargo and crewed missions to LEO – a proposal, which for unknown reasons, appears to have been pushed aside by NASA’s commercial space division.

It was never submitted by Boeing for either COTS or commercial crew development.

[Oli]

They should make the X-37 bigger until the centaur upper stage can be integrated. Would make a nice reusable 2nd stage 

[oiorionsbelt]

"While the Boeing presentation – created in 2011 for the AIAA – makes a fairly convincing case for the evolving capabilities of the X-37B, there is no indication at this time that pursuit of this option is ongoing or even under the slightest consideration from NASA."

Why?

[oiorionsbelt]

NASA is committed to commercial crew for LEO, each commercial crew bidder was only allowed to bid one system, and Boeing (the creator of X-37) bid CST-100 instead.

Did Boeing think they could get CST-100 ready before X-37 or was there another reason they chose the CST-100

X-37 seems like a far more capable/exciting vehicle.

[baldusi]

Since the X-37B belong to USAF, wouldn't have Boeing to reimburse them for the development? Could Boeing take what was made with public funding and use for commercial use? Or would it have to buy them back (probably under the cost)?
Looking at the conops it would seem that attaching items outside the fuselage inside the fairing leaves the problem of not damaging (nor penetrating) the TPS. And I still don't understand very well how are they going to transfer the internal cargo. Making a nano MLPM perhaps?
Besides the 1.5G item, it would seem to me that Dragon supplies a much easier and streamlined process for down mass. And both HTV/Dragon have a better enclosure for unpressurized cargo.
If they had gone with a full X-37C, and decided on using an airlock, then they would have as good a proposal as Dream Chaser, but be much more advanced state of development. Yet they didn't and thus they aren't. I still think an X-37C would be uber cool. But I see a much better proposal on an HL-42 to fill the role of LEO Taxi. As said above, the thin fuselage is not very volume efficient. And ISS cargo is usually volume limited. Plus an HL-42 derivative could do ISS racks + crew easily.
And even for a future "commercial" market, an HL-42 could carry something like 16 pax, which should offer a much better cost. Or carry all the necessary cargo for said passengers, thus solving the cargo issue altogether.

[Robotbeat]

More capable? CST-100 seems much more capable of BLEO than X-37(x).

[Star One]

More capable? CST-100 seems much more capable of BLEO than X-37(x).

Which is completely irrelevant here when it comes to servicing the ISS.

[manboy]

NASA is committed to commercial crew for LEO, each commercial crew bidder was only allowed to bid one system, and Boeing (the creator of X-37) bid CST-100 instead.

Did Boeing think they could get CST-100 ready before X-37 or was there another reason they chose the CST-100

X-37 seems like a far more capable/exciting vehicle.

More capable in what way?

[Robert Thompson]

Article said 1.5 g on landing. What can Dragon do wrt injuries/medical transport?

[oiorionsbelt]

More capable in what way?

fully autonomous, 1.5 G landing,

Hell, I should've just stuck with more exciting, and even then not really.
I think it "seems" more exciting than CST 100 but not Dragon
Maybe wings just tug at the heart strings, but they imply LEO and my heart is on Mars exploration by humans.
 I take it all back.....no wonder Boeing didn't put it forward as their proposal.

[Patchouli]

They should make the X-37 bigger until the centaur upper stage can be integrated. Would make a nice reusable 2nd stage 

You don't want to bite off too much at once so maybe save that for the X-37D.

Article said 1.5 g on landing. What can Dragon do wrt injuries/medical transport?

In theory Dragon should eventually be able to land close to civilization where an ambulance can meet up with it like the X-37C and DreamChaser though not as gentle of a ride.

But it will still be more limited in where it can land and in the number of landing opportunities per day.

Less cross range and it's easier to get permission for a glider to overfly a populated region then something coming down on rockets.

The CST-100 would be more limited in suitable landing locations then Dragon due to the need to detach the heat shield though this could be held off until fairly close to the landing point.
Sure it could in theory land in the boonies or in the ocean but that could be going from the frying pan into the fire for an incapacitated crew member.

[Robotbeat]

More capable? CST-100 seems much more capable of BLEO than X-37(x).

Which is completely irrelevant here when it comes to servicing the ISS.

not at all. A plan that has significant traction is to extend ISS to a Lagrange point, to facilitate BLEO exploration. That still has logistical needs.

[Lars_J]

It would seem like the main issue from Boeings side (if they could only submit one proposal) would be cost - I would think. To be of any practical use for ISS cargo or crew use, the X-37B would have to be scaled up and significantly modified. Or they could just dust off their old Orion proposal, a less complex development.

And for whatever reason, neither NASA nor DoD seem terribly attached to the X-37B - given the lack of flights and investments in new vehicles. So perhaps it isn't all that is hyped up to be from an operational perspective.

But I'm just spitballing as an outside observer.

[simonbp]

Orion is NASA's BLEO solution. ISS Commercial Crew solutions will be judged on the basis of ISS only, nothing more.

From the NASA perspective, maybe. SpaceX obviously has grandiose ambitions for Dragon, and I recall a Boeing engineer telling me CST was designed for lunar-class reentry velocities. The fact that CST is capable of such future missions (and an X-37 based vehicle is not) may have impacted the capsule being chosen as Boeing's bid.

[a_langwich]

Orion is NASA's BLEO solution. ISS Commercial Crew solutions will be judged on the basis of ISS only, nothing more.

From the NASA perspective, maybe. SpaceX obviously has grandiose ambitions for Dragon, and I recall a Boeing engineer telling me CST was designed for lunar-class reentry velocities. The fact that CST is capable of such future missions (and an X-37 based vehicle is not) may have impacted the capsule being chosen as Boeing's bid.

Or maybe it was the higher cost of a winged hypersonic reentry vehicle, coupled with less pressurized volume, and less usable payload weight.  That's for the X-37B. 

I have my doubts the X-37C would be a simple scale-up.  It would be unshrouded with a ~7.7m wingspan, and by my back-of-the-envelope scribbling it seems the weight ceiling (payload of an Atlas V 551/552, DIVH too expensive) might be a challenge too.   (1.7 ^3 = 4.91 x 5 mT X-37B loaded weight = 24.6 mT, plus pressurized space with life support system and pusher escape system.  Maybe that loaded weight included depleted uranium anvils to drop on DPRK,  though, and weight scaling isn't an issue.)

[manboy]

Orion is NASA's BLEO solution. ISS Commercial Crew solutions will be judged on the basis of ISS only, nothing more.

From the NASA perspective, maybe. SpaceX obviously has grandiose ambitions for Dragon, and I recall a Boeing engineer telling me CST was designed for lunar-class reentry velocities.

Well it's the same shape as the Apollo Command Module and uses the same material for its heatshield.

[phred]

CST was designed for lunar-class reentry velocities.

What kind of reentry velocities was X-37 designed for?

[Rocket Science]

Orion is NASA's BLEO solution. ISS Commercial Crew solutions will be judged on the basis of ISS only, nothing more.

From the NASA perspective, maybe. SpaceX obviously has grandiose ambitions for Dragon, and I recall a Boeing engineer telling me CST was designed for lunar-class reentry velocities. The fact that CST is capable of such future missions (and an X-37 based vehicle is not) may have impacted the capsule being chosen as Boeing's bid.

I  agree with you Simon as I felt that Boeing was hedging its bet with the choice of the CST-100 moldline...

[Patchouli]

Well it's the same shape as the Apollo Command Module and uses the same material for its heatshield.

I heard it's an all new material called BLA or Boeing light weight ablator probably similar to PICA.

If it is similar to PICA then it should be capable of lunar reentries with minor modifications.

Orion is NASA's BLEO solution. ISS Commercial Crew solutions will be judged on the basis of ISS only, nothing more.

From the NASA perspective, maybe. SpaceX obviously has grandiose ambitions for Dragon, and I recall a Boeing engineer telling me CST was designed for lunar-class reentry velocities. The fact that CST is capable of such future missions (and an X-37 based vehicle is not) may have impacted the capsule being chosen as Boeing's bid.

I remember reading lunar velocity reentries supposedly were one reason why SNC rejected the similar X-34 shape for their orbital vehicle.

With the X-34 shape temps on the TPS were just too close to the failure points to be comfortable.
Something within 200 to 400C of the failure point.
It sounds like a lot of margin but really it's a razor thin margin when you looking at temps of 3600C or more.

On the CST-100 I heard Boeing chose it because they could reuse much of the Apollo flight data.
You have good estimates of what to expect so not as much need for scale testing or to over engineer the TPS.

[Lars_J]

I have my doubts the X-37C would be a simple scale-up.  It would be unshrouded with a ~7.7m wingspan, and by my back-of-the-envelope scribbling it seems the weight ceiling (payload of an Atlas V 551/552, DIVH too expensive) might be a challenge too.   (1.7 ^3 = 4.91 x 5 mT X-37B loaded weight = 24.6 mT, plus pressurized space with life support system and pusher escape system.  Maybe that loaded weight included depleted uranium anvils to drop on DPRK,  though, and weight scaling isn't an issue.)

Yep, you are probably onto something here. The scale-up is not as trivial as some think.

[Robotbeat]

More capable? CST-100 seems much more capable of BLEO than X-37(x).

Which is completely irrelevant here when it comes to servicing the ISS.

not at all. A plan that has significant traction is to extend ISS to a Lagrange point, to facilitate BLEO exploration. That still has logistical needs.

Orion is NASA's BLEO solution. ISS Commercial Crew solutions will be judged on the basis of ISS only, nothing more.

Why?

EDIT:
That contradicts what is said here:
http://www.nasa.gov/offices/c3po/home/c3po_goal_objectives.html

Commercial Crew and Cargo Program Office (C3PO)
 
Program Goal

The C3PO will extend human presence in space by enabling an expanding and robust U.S. commercial space transportation industry.

Program Objectives

*Implement U.S. Space Exploration policy with investments to stimulate the commercial space industry

*Facilitate U.S. private industry demonstration of cargo and crew space transportation capabilities with the goal of achieving safe, reliable, cost effective access to low-Earth orbit

*Create a market environment in which commercial space transportation services are available to Government and private sector customers

Clearly, being usable for beyond-LEO is helpful for both the first and last bullet points.

[Lobo]

Orion is NASA's BLEO solution. ISS Commercial Crew solutions will be judged on the basis of ISS only, nothing more.

From the NASA perspective, maybe. SpaceX obviously has grandiose ambitions for Dragon, and I recall a Boeing engineer telling me CST was designed for lunar-class reentry velocities.

Well it's the same shape as the Apollo Command Module and uses the same material for its heatshield.

Isn't CST-100 based on Boeing's original proposal for Orion?  That lost out to LM's proposal? (Or I guess it would have been referred to as the "CEV" -Crew Exploration Vehicle, back then.  )
And LM later came out with an "Orion-Lite" concept based on the chosen Orion design, and was confused for awhile with CST-100 (perhaps before the name CST-100 was being commonly referred to as?).  But Orion Lite was based on LM's CEV proposal, where CST-100 was based on Boeing's CEV proposal.
If that's correct, it would seem by default to have the ability of lunar velocity reentries since it was based on a vehicle that was designed for that purpose.

[Lobo]

I have my doubts the X-37C would be a simple scale-up.  It would be unshrouded with a ~7.7m wingspan, and by my back-of-the-envelope scribbling it seems the weight ceiling (payload of an Atlas V 551/552, DIVH too expensive) might be a challenge too.   (1.7 ^3 = 4.91 x 5 mT X-37B loaded weight = 24.6 mT, plus pressurized space with life support system and pusher escape system.  Maybe that loaded weight included depleted uranium anvils to drop on DPRK,  though, and weight scaling isn't an issue.)

Yep, you are probably onto something here. The scale-up is not as trivial as some think.

Yea, I think the time for the X-37B to be used as a demonstrator for an X-37C “mini-shuttle” to be used to service the ISS was maybe way back during ESAS, if ESAS would have entertained such a vehicle for LEO service, while then developing the CEV for BLEO operation.  It still would have been somewhat redundant because the CEV was intended to be fully capable of servicing the ISS, as well as act as a cargo carrier with the CEV service module (per the ESAS report).  Still, it might not have been a bad backup to use in conjunction with the CEV/Orion and launching on a single stick Atlas variant.  Orion could also launch on an Atlas-552, just not with it’s full TEI propellant load in it’s service module, which it would need for a lunar mission, and thus NASA felt they needed to develop Ares 1 unfortunately.  (Of course, AVH would have been a far easier development program than Ares 1, and thus a single stick Atlas would be man-rated for launching Orion and X-37C to the ISS…but we’ll not go down that road here.  :-) )

As it sits now, as cool as the X-37B is, it’s just too small I think to really be of much use to the ISS.  I think it really is a demonstrator, rather than a useful vehicle unto itself.  Which means an X-37C would have to be developed.  But there is already a reusable space plane of similar size and capability that will launch on a man-rated Atlas if memory serves.  (what’s the name of that thing?....Dream-something I think… ;-)  )  And it’s already pretty far along, where X-37C would have to be started from scratch.

Plus, we are already running into the problem of too many LEO spacecraft for ISS servicing, not too few.  Which means lots of development costs and low flight rates.  There will be one, two , or even maybe three vehicles completely or near completely developed for Commercial Crew.  There are two for Commercial Cargo.  Plus there’s always Orion, which is the official ISS crew backup I think (I believe I read that somewhere) and really could launch to the ISS on an Atlas-552 as I mentioned before.  Like Apollo launching on Saturn 1B, it only needs a fraction of it’s 8mt service module main propellant capacity to go to the ISS.  Once Atlas is man-rated, it’ll be curious if NASA develops a payload adaptor to fit Orion, just in case.  Then they wouldn’t have to stack and roll out a whole Block 1 SLS if Orion needs to get to the ISS for some reason.  Just launch from where ever CST-100 or DC are launching from. 

[Lobo]

It would be more accurate to say that both NG/Boeing's CEV proposal and CST-100 are based on Boeing's OSP proposal.

Yea, I kinda forgot about how the CEV program was started.  (or more accurately, I wasn't following it much back then).  with lifting bodies as CEV's.  And then those contractor designes were thrown out, and NASA said they'd design the CEV as a big capsule, and then award a contract ot build their design. 

http://www.astronautix.com/craft/cev.htm

So I think CST-100 was based on some of that initial work done by Boeing before the actual contract to build Orion was awarded to LM?

Man...it just seems like things work SO much better/faster/cheaper when the contractor is just given performance requirements, and then comes up with their own design, rather than NASA designing it and telling a contractor to build it.  Nothing that hasn't been said 100 times around here...but you'd think someone would look back at history and figure that out.  :-)

[Lobo]

I have my doubts the X-37C would be a simple scale-up.  It would be unshrouded with a ~7.7m wingspan, and by my back-of-the-envelope scribbling it seems the weight ceiling (payload of an Atlas V 551/552, DIVH too expensive) might be a challenge too.   (1.7 ^3 = 4.91 x 5 mT X-37B loaded weight = 24.6 mT, plus pressurized space with life support system and pusher escape system.  Maybe that loaded weight included depleted uranium anvils to drop on DPRK,  though, and weight scaling isn't an issue.)

Yep, you are probably onto something here. The scale-up is not as trivial as some think.

On a bit of a hypothetical direction, how big could the X-37 geometry be made?  Could it be made (or have been made) into something the size of the STS orbiter?  Except with a hydrolox tank and J2 derivative engines on the back where the storable tanks are on the X-37B?  And then the orbiter would have been launched vertically on a booster rather than side mount.
Is the design scalable up that large?  Or is it only feasible in smaller sizes like the X-37B or C?

[Lobo]

I suspect you're still not comprehending.

Boeing's OSP proposal was a capsule. The name "OSP" itself was a misnomer; it wasn't limited to spaceplanes.

CST-100 is a younger sibling of NG/Boeing's CEV, not a child of it.

So, Boeing’s “Orbital Space Plane” was actually a capsule.  Umm….yea…I guess I didn’t comprehend that.  ;-)

But it makes sense, as I couldn’t pull up any images for an actual orbital space plane from Boeing for the CEV competition.  Only the one by LM.   It kept showing a capsule proposal from Boing for it’s “OSP” for the CEV competition.
And then references to X-40 and X-37 “Orbital Space Plane” for NASA’s “Space Launch Initiative” program.

Again, in this Astronautix page on the CEV, it looks like it shows a Boeing plane “OSP”, and a capsule “OSP”.

http://www.astronautix.com/craft/cev.htm

So I’m guessing that CST-100 was based on the ballistic capsule “OSP”?

But yea, I’ll be the first to admit I’m not well read up on all the history of that time.  But I’m learning more now.

[vt_hokie]

I suspect you're still not comprehending.

Boeing's OSP proposal was a capsule. The name "OSP" itself was a misnomer; it wasn't limited to spaceplanes.

CST-100 is a younger sibling of NG/Boeing's CEV, not a child of it.

So, Boeing’s “Orbital Space Plane” was actually a capsule.  Umm….yea…I guess I didn’t comprehend that.  ;-)

Well, at one point it was an X-37 based space plane design:

http://www.boeing.com/news/releases/2003/q2/nr_030418s.html

[Elmar Moelzer]

Yeah, IIRC, they had concepts for both.

[QuantumG]

"space plane" apparently means "reuse operations similar to an aircraft", and doesn't include the booster phase.. or so I've heard capsule pushers suggest.

If the booster phase is included, the term "gas-and-go" can be used, but probably won't be.

[Jim]

"space plane" apparently means "reuse operations similar to an aircraft", and doesn't include the booster phase.. or so I've heard capsule pushers suggest.

That wasn't the goal of OSP

[Elmar Moelzer]

That wasn't the goal of OSP

A lot of people, me included have wondered what the goals of the OSP really were... I thought it was not particularly "inspired" a program.

[Jim]

A lot of people, me included have wondered what the goals of the OSP really were... I thought it was not particularly "inspired" a program.

It wasn't a lot.

Same goal as Commercial Crew without the commercial part.

[Elmar Moelzer]

A lot of people, me included have wondered what the goals of the OSP really were... I thought it was not particularly "inspired" a program.

It wasn't a lot.

Same goal as Commercial Crew without the commercial part.

Yeah, only that the "commercial" part makes all the difference.

[Jim]

A lot of people, me included have wondered what the goals of the OSP really were... I thought it was not particularly "inspired" a program.

It wasn't a lot.

Same goal as Commercial Crew without the commercial part.

Yeah, only that the "commercial" part makes all the difference.

Nah, that is a minor part of it

[Elmar Moelzer]

A lot of people, me included have wondered what the goals of the OSP really were... I thought it was not particularly "inspired" a program.

It wasn't a lot.

Same goal as Commercial Crew without the commercial part.

Yeah, only that the "commercial" part makes all the difference.

Nah, that is a minor part of it

No, it isnt a "minor" part of it.

[vulture4]

OSP was intended to provide manned access to ISS initially as a backup to Shuttle and later as a replacement. Boeing and Orbital were each asked to provide two proposals for OSP, a winged vehicle and a capsule. Boeing proposed a capsule somewhat similar to the CST and a winged vehicle based on the X-37 although larger.  Orbital proposed a similar capsule and a winged vehicle called Prometheus. The OSP program was cancelled in favor of Constellation but before this occurred NASA indicated a preference for the capsule because it had a larger internal volume. This may have influenced Boeing to propose the capsule for the CCDev program. Orbital again proposed the Prometheus for CCDev but was not funded, partly because it had only four seats, although this clearly met the minimum requirement. The capsules held seven. Sierra Nevada's lifting body held six and was based on a side-by-side seating configuration with liked by the astronauts with two front seats directly behind a windshield, and still received less funding than the Dragon and CST.

The X-37C could carry six and had about the same internal volume as the Dreamchaser. The round pressurized cabin would have been easier to fabricate but was longer and thinner, making it necessary for the six crew to sit single file, and difficult to put even one crewman behind a traditional pilot's canopy. Of course it can land perfectly well on autopilot or with the pilot flying by video camera but this would not go over well. I think Boeing simply saw that NASA was more likely to choose a seven-seat capsule design, and that it would be easier and less expensive to build.

I still feel the wing-and-fuselage designs are better aerodynamically than lifting bodies for any given landing mass and volume. Lifting bodies are very difficult to land because of their high drag and low lift and require very high touchdown speeds. As size and mass increase, landing a lifting body in gliding flight becomes impossible, and anything significantly heavier than the Dreamchaser would have to use a parachute, rockets or some similar method to support its weight during landing, leaving it with little or no advantage over a capsule. In contrast, a winged spacecraft can land at a mass of 100 tons or more. This was why wings were chosen for the Shuttle after a decade of work with lifting bodies.

[QuantumG]

The OSP program was    cancelled in favor of Constellation

OSP was cancelled for a "streamlined" program to make the Crew Exploration Vehicle and took at lot of OSP with it.. but so did Constellation. Both changes slowed the program and left devastation, but the ultimate result of the OSP-capsule proposals was Orion. Ultimate so far anyway, who knows what the international effort will do to it.

An elephant is a mouse built to government specifications.

[vulture4]

OSP was cancelled for a "streamlined" program to make the Crew Exploration Vehicle and took at lot of OSP with it.. but so did Constellation. Both changes slowed the program and left devastation, but the ultimate result of the OSP-capsule proposals was Orion.

From a programmatic point I agree with your evolution. But OSP was most emphatically a program to provide human access to LEO only, as thre CAIB recommended. Constellation at first abandoned LEO in an attempt to recapture the glory of Apollo, then added it as a secondary task for which it was poorly suited. It wasn't the changes that left devastation, it was the lack of a practical goal.

CCDev is very much a return to the goals, strategies, and vehicle designs of OSP, with  the major changes being the addition of SpaceX and Sierra Nevada and the reduced level of NASA oversight.

[QuantumG]

From a programmatic point I agree with your evolution. But OSP was most emphatically a program to provide human access to LEO only, as thre CAIB recommended.

There was no real distinction made between LEO and beyond back then.. a capsule is a capsule. They had to make up some 6-month capsule mission fiction in order to justify Orion and then they did a poor job of it anyway.

Constellation at first abandoned LEO in an attempt to recapture the glory of Apollo, then added it as a secondary task for which it was poorly suited.

There ya go again... you do understand the CEV existed before Constellation right?

It wasn't the changes that left devastation, it was the lack of a practical goal.

No, it was the changes. The lack of any goal is just the reason for the continual changes and non-commitment.

CCDev is very much a return to the goals, strategies, and vehicle designs of OSP, with  the major changes being the addition of SpaceX and Sierra Nevada and the reduced level of NASA oversight.

and there's still no agreement on goals. Is it building an industry? Or not? What for? Is it supposed to save money? Why? Why not? Ask 3 congressional staffers and you'll get 5 answers.

[Patchouli]

OSP was intended to provide manned access to ISS initially as a backup to Shuttle and later as a replacement. Boeing and Orbital were each asked to provide two proposals for OSP, a winged vehicle and a capsule. Boeing proposed a capsule somewhat similar to the CST and a winged vehicle based on the X-37 although larger.  Orbital proposed a similar capsule and a winged vehicle called Prometheus. The OSP program was cancelled in favor of Constellation but before this occurred NASA indicated a preference for the capsule because it had a larger internal volume. This may have influenced Boeing to propose the capsule for the CCDev program. Orbital again proposed the Prometheus for CCDev but was not funded, partly because it had only four seats, although this clearly met the minimum requirement. The capsules held seven. Sierra Nevada's lifting body held six and was based on a side-by-side seating configuration with liked by the astronauts with two front seats directly behind a windshield, and still received less funding than the Dragon and CST.

The X-37C could carry six and had about the same internal volume as the Dreamchaser. The round pressurized cabin would have been easier to fabricate but was longer and thinner, making it necessary for the six crew to sit single file, and difficult to put even one crewman behind a traditional pilot's canopy. Of course it can land perfectly well on autopilot or with the pilot flying by video camera but this would not go over well. I think Boeing simply saw that NASA was more likely to choose a seven-seat capsule design, and that it would be easier and less expensive to build.

I still feel the wing-and-fuselage designs are better aerodynamically than lifting bodies for any given landing mass and volume. Lifting bodies are very difficult to land because of their high drag and low lift and require very high touchdown speeds. As size and mass increase, landing a lifting body in gliding flight becomes impossible, and anything significantly heavier than the Dreamchaser would have to use a parachute, rockets or some similar method to support its weight during landing, leaving it with little or no advantage over a capsule. In contrast, a winged spacecraft can land at a mass of 100 tons or more. This was why wings were chosen for the Shuttle after a decade of work with lifting bodies.

The X-33 and Venture star were lifting body designs.

The wing and tube design for the orbiter was more well understood and could borrow a lot of research from the the X-15 and Dynasoar programs.
Orion having an Apollo shape despite it being a some what inefficient shape was for the same reasons.

There are better shapes see Spacex's and Blue Origin's capsules but these come with greater risk.

Though wings do offer better glide then a lifting body.

Surprisingly the Rockwell X-33 did not win out as it pretty much reused the STS orbiter OML.
It's construction was to be much more conventional too.

[go4mars]

There are better shapes see Spacex's and Blue Origin's capsules but these come with greater risk.

How do you figure the "greater risk" part?

[Lar]

There are better shapes see Spacex's and Blue Origin's capsules but these come with greater risk.

How do you figure the "greater risk" part?

Maybe because those shapes haven't had as much flight experience?

Just a guess/attempt to read Patchouli's mind...

[Elmar Moelzer]

Surprisingly the Rockwell X-33 did not win out as it pretty much reused the STS orbiter OML.
It's construction was to be much more conventional too.

I thought the same. Some people say that NASA deliberately went for the most ambitious of the proposals. The one with the most new technology in it. Didnt learn from the shuttle...

[Star One]

Surprisingly the Rockwell X-33 did not win out as it pretty much reused the STS orbiter OML.
It's construction was to be much more conventional too.

I thought the same. Some people say that NASA deliberately went for the most ambitious of the proposals. The one with the most new technology in it. Didnt learn from the shuttle...

That seems a curious decision to make, why not go the more tried and tested route?

[Jim]

Surprisingly the Rockwell X-33 did not win out as it pretty much reused the
I thought the same. Some people say that NASA deliberately went for the most ambitious of the proposals. The one with the most new technology in it. Didnt learn from the shuttle...

Typical of a NASA basher, you are talking out of both sides of your mouth.   

You said the shuttle was too great of a leap and should not have been an operational system but a technology development program.  X-33 is exactly what NASA should be doing, it was a technology development program. 

[Elmar Moelzer]

You said the shuttle was too great of a leap and should not have been an operational system but a technology development program.  X-33 is exactly what NASA should be doing, it was a technology development program. 

So was the X33, if dear sir had bothered to read my full post. The X-33 Venture star was the most ambitious of all proposals.

[HMXHMX]

Surprisingly the Rockwell X-33 did not win out as it pretty much reused the
I thought the same. Some people say that NASA deliberately went for the most ambitious of the proposals. The one with the most new technology in it. Didnt learn from the shuttle...

Typical of a NASA basher, you are talking out of both sides of your mouth.   

You said the shuttle was too great of a leap and should not have been an operational system but a technology development program.  X-33 is exactly what NASA should be doing, it was a technology development program. 

Jim, the lead up to the X-33 program was focused more on the demonstration of a viable high flight rate CONOPS than generic technology development.  While there was a desire (and need) for technology development to both support that aim and the flight rate improvement, for many of those of us involved technology (as NASA usually uses the term) wasn't the prime driver.  (In fact, I lost the argument that a high mass fraction demonstration for SSTO had to be a primary component of DC-X along with the operability demo.)

Further, Gary Payton specifically told me that as Source Selection Authority he chose the most ambitious of the proposals (this was also echoed at the public announcement, though I don't recall if Gary or Dan Golden said it).  Since I regard Gary as a friend, it pained me to have to publicly disagree with his management of the X-33 in front of a Congressional committee a short while afterwards – he and I being the only two witnesses.  I still think selecting the LM proposal was  a serious error of judgement.  And while I personally promoted the MDAC VTOL approach, I would have been much happier to see Rockwell win (with a very fine proposal, I might add) in place of LM.

(I hasten to add that "technology" is so generic a word in our business as to be almost meaningless.  I wanted to see development and test progress on a number of fronts, but felt that propulsion (a major focus of X-33's efforts) need not be among them.  The RL-10 used for DC-X and even the SSME of the day would have been perfectly acceptable to employ for a near SSTO demonstrator that could have flown on a weekly basis, for example.)

[Elmar Moelzer]

Jim, the lead up to the X-33 program was focused more on the demonstration of a viable high flight rate CONOPS than generic technology development.  While there was a desire (and need) for technology development to both support that aim and the flight rate improvement, for many of those of us involved technology (as NASA usually uses the term) wasn't the prime driver.  (In fact, I lost the argument that a high mass fraction demonstration for SSTO had to be a primary component of DC-X along with the operability demo.)

Further, Gary Payton specifically told me that as Source Selection Authority he chose the most ambitious of the proposals (this was also echoed at the public announcement, though I don't recall if Gary or Dan Golden said it).  Since I regard Gary as a friend, it pained me to have to publicly disagree with his management of the X-33 in front of a Congressional committee a short while afterwards – he and I being the only two witnesses.  I still think selecting the LM proposal was  a serious error of judgement.  And while I personally promoted the MDAC VTOL approach, I would have been much happier to see Rockwell win (with a very fine proposal, I might add) in place of LM.

(I hasten to add that "technology" is so generic a word in our business as to be almost meaningless.  I wanted to see development and test progress on a number of fronts, but felt that propulsion (a major focus of X-33's efforts) need not be among them.  The RL-10 used for DC-X and even the SSME of the day would have been perfectly acceptable to employ for a near SSTO demonstrator that could have flown on a weekly basis, for example.)

Glad to read a first hand account of this, Gary!

[vulture4]

The goals of OSP and CC (for NASA) are quite similar and for Boeing the design is similar as well, but IMO SpaceX has integrated human launch with ISS cargo and booster development and appears capable of reducing costs compared with the original OSP concept of sticking with the EELVs. "Commercial" is still largely government funded but provides greater flexibility and less government oversight in both development and operations.

[vulture4]

The RL-10 used for DC-X and even the SSME of the day would have been perfectly acceptable to employ for a near SSTO demonstrator that could have flown on a weekly basis, for example.)

Was there ever a near SSTO design with conventional engines? Why do you think SSTO capability was so critical? Wouldn't it require an impractically small payload mass fraction? I heard when X-33 was cancelled that one reason was the conclusion that the planned operational derivative of the design could not achieve SSTO. Others said that flying the prototype as a suborbital would still provide useful information.

[HMXHMX]

The RL-10 used for DC-X and even the SSME of the day would have been perfectly acceptable to employ for a near SSTO demonstrator that could have flown on a weekly basis, for example.)

Was there ever a near SSTO design with conventional engines? Why do you think SSTO capability was so critical? Wouldn't it require an impractically small payload mass fraction? I heard when X-33 was cancelled that one reason was the conclusion that the planned operational derivative of the design could not achieve SSTO. Others said that flying the prototype as a suborbital would still provide useful information.

We'd be well off topic if I replied in detail, except to say "yes" to your first question, there have been concept designs.  And X-33 was never configured or expected to be orbital, only suborbital.  The rest of the conversation should be in another thread, probably.

[Falcon H]

Wow it sounds like dream chaser might get some competition.

[Lar]

Glad to read a first hand account of this, Gary!

Ditto... just another reason why NSF is awesome.

I have to agree with the assessment that going for the most advanced vehicle tech may have been a mistake if the key deliverable was rapid/cheap reusability demonstration.

[Patchouli]

There are better shapes see Spacex's and Blue Origin's capsules but these come with greater risk.

How do you figure the "greater risk" part?

Maybe because those shapes haven't had as much flight experience?

Just a guess/attempt to read Patchouli's mind...

The lack of flight experience is pretty much the reason for increased risk.
But for Spacex the payoff was worth while as they pretty much reinvented to concept of a capsule vehicle.

Surprisingly the Rockwell X-33 did not win out as it pretty much reused the
I thought the same. Some people say that NASA deliberately went for the most ambitious of the proposals. The one with the most new technology in it. Didnt learn from the shuttle...

Typical of a NASA basher, you are talking out of both sides of your mouth.   

You said the shuttle was too great of a leap and should not have been an operational system but a technology development program.  X-33 is exactly what NASA should be doing, it was a technology development program. 

Jim, the lead up to the X-33 program was focused more on the demonstration of a viable high flight rate CONOPS than generic technology development.  While there was a desire (and need) for technology development to both support that aim and the flight rate improvement, for many of those of us involved technology (as NASA usually uses the term) wasn't the prime driver.  (In fact, I lost the argument that a high mass fraction demonstration for SSTO had to be a primary component of DC-X along with the operability demo.)

Further, Gary Payton specifically told me that as Source Selection Authority he chose the most ambitious of the proposals (this was also echoed at the public announcement, though I don't recall if Gary or Dan Golden said it).  Since I regard Gary as a friend, it pained me to have to publicly disagree with his management of the X-33 in front of a Congressional committee a short while afterwards – he and I being the only two witnesses.  I still think selecting the LM proposal was  a serious error of judgement.  And while I personally promoted the MDAC VTOL approach, I would have been much happier to see Rockwell win (with a very fine proposal, I might add) in place of LM.

(I hasten to add that "technology" is so generic a word in our business as to be almost meaningless.  I wanted to see development and test progress on a number of fronts, but felt that propulsion (a major focus of X-33's efforts) need not be among them.  The RL-10 used for DC-X and even the SSME of the day would have been perfectly acceptable to employ for a near SSTO demonstrator that could have flown on a weekly basis, for example.)

OT but the X-33 being so tightly tied to Venture star was it's biggest problem.
When the composite tanks ran into delays they should have went ahead and flew it with metal tanks.

Back on topic on the OTV-2 flight they did demonstrate the storage of a complex reentry vehicle in space for the duration of a Mars Mission.

[Star One]

A small update from the USAF about the X-37B.

The X-37B reusable spaceplane has “great utility” and the Air Force intends to keep using it “for a while” because it is helping service officials understand the “re-usability aspect of space” for satellites, said Gen. John Hyten, Air Force Space Command boss, on Thursday at AFA’s Air Warfare Symposium in Orlando, Fla. “That is the fundamental thing that X-37 is really getting at,” he said during a meeting with reporters. Pretty much everything the Air Force does in space is “a throwaway,” said Hyten.

http://www.airforcemag.com/DRArchive/Pages/2015/February%202015/February%2013%202015/The-X-37B-and-the-Satellite-Throwaway-Paradigm.aspx

[baldusi]

Well, I'm of the idea that the STS program should have been preceded by an HL20 on a human rated Titan IIID, so NASA could understand the technical and operative issues of using a reusable crewed vehicle with reusable SSRB.
If somehow USAF is planning on reusable satellites (which I'm not sure it is the actual objective), then they have learned their lesson.

[Star One]

Well, I'm of the idea that the STS program should have been preceded by an HL20 on a human rated Titan IIID, so NASA could understand the technical and operative issues of using a reusable crewed vehicle with reusable SSRB.
If somehow USAF is planning on reusable satellites (which I'm not sure it is the actual objective), then they have learned their lesson.

Maybe OT for here but I sometimes wonder if the X-37B is some kind of precursor to the USAF developing its own independent reusable access to LEO.

[Jim]

No, x-37 is spacecraft

[Star One]

No, x-37 is spacecraft

But one that still significantly carries an X designation.

[baldusi]

No, x-37 is spacecraft

I see the X-37 as an X-craft, i.e. a learning and experimenting tool. Nothing more and nothing less than that. If they suddenly learn a way to do a fully reusable LV, then we'll see in the future the necessary projects. If they learn how to reuse satellite parts, great, if they just understand and improve the degradation characteristics of the sensors that are critical to the defense of their country, so much the better. Let's not read too much.

[Jim]

X doesn't mean anything in that context.  Also, independent from what? The air force can Develop a reusable system if it wanted to. It would announce that it was doing so and wouldn't hide it

[Blackstar]

No, x-37 is spacecraft

I see the X-37 as an X-craft, i.e. a learning and experimenting tool. Nothing more and nothing less than that. If they suddenly learn a way to do a fully reusable LV, then we'll see in the future the necessary projects. If they learn how to reuse satellite parts, great, if they just understand and improve the degradation characteristics of the sensors that are critical to the defense of their country, so much the better. Let's not read too much.

Despite the designation, the X-37B is clearly an operational spacecraft. They've launched it several times, kept it in orbit for very long missions, and clearly plan to fly it at least several times in the future. That's operational.

[Herb Schaltegger]

By that (expanded) definition, nearly every single X-craft has been "operational."

[Ben the Space Brit]

I've long thought that X-37B deserves a new prefix to symbolise its move from experiment to operational asset. I'm thinking that the best one would be "RQ-", the same as the reconnaissance drones.

However, there is a precedent for this not happening. The Lockheed F-117 Nighthawk got its number designation, partly for security reasons (F-112 to -116 were captured/stolen WarPac airframes under evaluation by the USAF) and partly because the USAF were worried that they'd get fewer volunteers for the squadrons of what was going to become a primary air strike asset if they used the more accurate but less-'sexy' A-11 designation.

So, for these birds to retain the X-37B designation for ease of identification and to create an at least official shield of denial about their operational role (even if, unofficially, they know that no-one is fooled) would not be unprecedented.

[Darren_Hensley]

No, x-37 is spacecraft

I see the X-37 as an X-craft, i.e. a learning and experimenting tool. Nothing more and nothing less than that. If they suddenly learn a way to do a fully reusable LV, then we'll see in the future the necessary projects. If they learn how to reuse satellite parts, great, if they just understand and improve the degradation characteristics of the sensors that are critical to the defense of their country, so much the better. Let's not read too much.

Despite the designation, the X-37B is clearly an operational spacecraft. They've launched it several times, kept it in orbit for very long missions, and clearly plan to fly it at least several times in the future. That's operational.

The X-stands for experimental, but that doesn't mean operational. Thousands of experimental aircraft went on to become operational. Nearly all have changed the designation only after going into production. A P51-D flying today would get an X- registration number, it does not change the fact that it was an operational fighter aircraft. The F-16XL is never going into production and will retain it's designation, no matter how long the USAF and NASA want to fly it. Just when you think there are rules, exceptions sometimes become the default standards.

[baldusi]

No, x-37 is spacecraft

I see the X-37 as an X-craft, i.e. a learning and experimenting tool. Nothing more and nothing less than that. If they suddenly learn a way to do a fully reusable LV, then we'll see in the future the necessary projects. If they learn how to reuse satellite parts, great, if they just understand and improve the degradation characteristics of the sensors that are critical to the defense of their country, so much the better. Let's not read too much.

Despite the designation, the X-37B is clearly an operational spacecraft. They've launched it several times, kept it in orbit for very long missions, and clearly plan to fly it at least several times in the future. That's operational.

What what you are trying to make experiments about long term reusability operations? You have to actually make multiple missions. Which is exactly what they are doing. Now, if there was a third and fourth aircrafts, I would say is a fully operational craft. But if they just keep flying this, I don't.

[RanulfC]

No, x-37 is spacecraft

I see the X-37 as an X-craft, i.e. a learning and experimenting tool. Nothing more and nothing less than that. If they suddenly learn a way to do a fully reusable LV, then we'll see in the future the necessary projects. If they learn how to reuse satellite parts, great, if they just understand and improve the degradation characteristics of the sensors that are critical to the defense of their country, so much the better. Let's not read too much.

Despite the designation, the X-37B is clearly an operational spacecraft. They've launched it several times, kept it in orbit for very long missions, and clearly plan to fly it at least several times in the future. That's operational.

Uhm Blackstar? By that definition the X-15 was an "operational" hypersonic and spacecraft And it's got the X-37 beat with "operational" flights by a huge margin. And to be brutally honest there would have to be at LEAST three X-37s if not more to be an "operational" vehicle...

No it's an "X" craft for a reason and that reason is it (and its missions lets not forget) are "experimental" in nature at well as mission

Randy

[Blackstar]

They are not flying X-37B to learn things from it to make a better vehicle in the future.

Don't be deceived by the fact that they didn't change the name when they gave it a mission to perform. They are using it to fly payloads. It's a carrier spacecraft, like the U-2 or the WB-57 carry payloads in the atmosphere. Clearly operational.

[Star One]

They are not flying X-37B to learn things from it to make a better vehicle in the future.

Don't be deceived by the fact that they didn't change the name when they gave it a mission to perform. They are using it to fly payloads. It's a carrier spacecraft, like the U-2 or the WB-57 carry payloads in the atmosphere. Clearly operational.

Well that article I linked to recently from Airforce magazine seemed to suggest the opposite to some degree as it talked of then learning about operating a reusable vehicle.

[arachnitect]

They are not flying X-37B to learn things from it to make a better vehicle in the future.

Don't be deceived by the fact that they didn't change the name when they gave it a mission to perform. They are using it to fly payloads. It's a carrier spacecraft, like the U-2 or the WB-57 carry payloads in the atmosphere. Clearly operational.

What can this vehicle do that wouldn't be easier with an OrbATK or Ball Aerospace bus?

Are they flying film again?