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.)