Author Topic: t/Space CCDEV2 Concept (Read 79663 times)

HMXHMX · « **on:** 04/18/2011 11:34 pm »

Since I was asked if I'd provide any information on the t/Space CCDEV2 concept on another now-locked thread, I am starting this thread to provide a brief I presented at the Space Access 2011 conference.

I'll be happy to answer reasonable questions as time permits.

sdsds · « **Reply #1 on:** 04/18/2011 11:53 pm »

Great concept!

Did you get any feedback on placing the OM behind the XV? Does forward-first re-entry mean there's no issue with access to the OM through the rear of the XV? Also, does this mean the OM could be stretched to fit a mission-specific need, without interfering with XV abort or re-qualifying the XV in any way? (Obviously Soyuz can't do that....)

Lars_J · « **Reply #2 on:** 04/18/2011 11:53 pm »

Very interesting, thanks for posting that!

I'm curious about the reentry orientation - it is relatively stable due to mass distribution (?) or would it need constant thruster firing to maintain? A complex shape like that would appear to favor going in head-first since it appears to be shaped like a truncated shuttlecock with the fuel tanks in front - at least that is what it looks like to this amateur observer.

HMXHMX · « **Reply #3 on:** 04/18/2011 11:59 pm »

Quote from: sdsds on 04/18/2011 11:53 pm

Great concept!

Did you get any feedback on placing the OM behind the XV? Does forward-first re-entry mean there's no issue with access to the OM through the rear of the XV? Also, does this mean the OM could be stretched to fit a mission-specific need, without interfering with XV abort or re-qualifying the XV in any way? (Obviously Soyuz can't do that....)

No feedback what so ever. Rather obviously, I disagree with the selection authority on the subject of technical maturity. But that is water over the dam.

I'm not sure I understand the access question, but there is a hatch at the rear of the XV crew module.

The OM could be stretched as necessary for mission specific requirements, and subject to LV lift capability. The OM doesn't participate in the abort, so stretching it (or eliminating it, in the "solo" option) has no effect.

HMXHMX · « **Reply #4 on:** 04/19/2011 12:02 am »

Quote from: Lars_J on 04/18/2011 11:53 pm

Very interesting, thanks for posting that!

I'm curious about the reentry orientation - it is relatively stable due to mass distribution (?) or would it need constant thruster firing to maintain? A complex shape like that would appear to favor going in head-first since it appears to be shaped like a truncated shuttlecock with the fuel tanks in front - at least that is what it looks like to this amateur observer.

Yes, it trims naturally at about 12 degrees AoA. We also used a trick of mounting batteries and certain other heavy items on a track that could be adjusted fore and aft, allowing on-the-fly trimming of Cg. Entry control is via roll-to-bank, so only roll thrusters are fired, as necessary.

synchrotron · « **Reply #5 on:** 04/19/2011 01:13 am »

Interesting material. Thank you for sharing this. The OV bears a strong outward similarity to the Kistler K-1 OV. A result of similar trades?

baldusi · « **Reply #6 on:** 04/19/2011 01:14 am »

What were the perceived weaknesses of the design? Isn't it a cylinder kind of "weak" structurally for reentry? I mean, with my absolute lack of aerodynamics.

HMXHMX · « **Reply #7 on:** 04/19/2011 01:23 am »

Quote from: synchrotron on 04/19/2011 01:13 am

Interesting material. Thank you for sharing this. The OV bears a strong outward similarity to the Kistler K-1 OV. A result of similar trades?

It wasn't a complete coincidence.

The basic moldline actually derived from the HMX Alt-Access ISS contingency resupply vehicle proposed to NASA in 2000. In turn, that derived from a Lockheed crew rescue concept from the late 1980s.

HMXHMX · « **Reply #8 on:** 04/19/2011 01:25 am »

Quote from: baldusi on 04/19/2011 01:14 am

What were the perceived weaknesses of the design? Isn't it a cylinder kind of "weak" structurally for reentry? I mean, with my absolute lack of aerodynamics.

You'd have to ask NASA.

As for structure, pretty much any object can be made to re-enter safely. Loads are much greater on ascent than entry.

Downix · « **Reply #9 on:** 04/19/2011 01:28 am »

Whenever tSpace shows up, you know the concept will be wild. Thanks for not disappointing.

HMXHMX · « **Reply #10 on:** 04/19/2011 01:34 am »

Quote from: Downix on 04/19/2011 01:28 am

Whenever tSpace shows up, you know the concept will be wild. Thanks for not disappointing.

And here I thought I was being rather conventional. I'm fairly sure Sergei Pavlovich would agree.

You want wild, I've done wild.

synchrotron · « **Reply #11 on:** 04/19/2011 01:23 pm »

In slide 5, the XV is shown in comparison to other proposed CCDEV silhouettes. What is this slide trying to sell? The Cygnus and Dragon vehicles have the service modules. But the XV lacks its OV. Is the slide showing that the XV is generally more compact than the others, or just that it's in the same class? Sorry if I'm reading into this more than was intended.

baldusi · « **Reply #12 on:** 04/19/2011 02:54 pm »

Your grouping is similar to the other capsules, namely an capsule with an integrated LAS, with a service module behind it. Where you propose a different solution, is in the layout of the pressure vessel (rather like a cylinder), the concept of a heat shield that can take multiple internal pressure vessels (if I'm not reading it wrong), and putting an integrated pusher liquid LAS on the tip. I'm assuming this is made so the system can be reused, and it simplifies the connection to the service module and is sort of autostabilizing.
On the other hand, if it was a true pusher system, it wouldn't have cosine losses and it could be optionally disposed if it was used as a booster stage.
BTW, on the fifth page ("Comparison to Other CCDEV Crewed Spacecraft") the passengers seem to be pointing downwards like in the escape capsule, but are only eight, like in the proposed transport.

Space Pete · « **Reply #13 on:** 04/19/2011 03:51 pm »

Nice concept!

Launching cargo with crew kinda makes sense - if the Atlas V/Falcon 9 has the up-mass to do it, then why not? I mean, why do in two launches what could be done in one? Shame it didn't get funded, but I hope work continues on it.

Robotbeat · « **Reply #14 on:** 04/19/2011 04:19 pm »

There's always the possibility of private investment. If your concept really is cheaper and better, it may be possible to partner with someone, especially if a market is demonstrated.

clongton · « **Reply #15 on:** 04/19/2011 04:30 pm »

I like what you have done and I have 3 questions.

1. I noticed that during launch the crew is forward facing, and during descent the crew is rearward facing. Is there no pilot station? I ask because I question the need for reorientation. The presentation says the re-entry loading is < 2g's and I don't understand why the seats need to be rotated in that benign environment.

2. Was any design consideration given to the OM actually being a Bigelow inflatable? It looks to be a perfect match.

3. What is the contingency landing mode if the helecopter misses the grab?

Thanks for sharing this.

jongoff · « **Reply #16 on:** 04/19/2011 05:06 pm »

Chuck,
I think Gary was saying at Space Access that the landing point would be picked near a body of water so that if the helicopter snatch failed, it could still safely do a water landing.

~Jon

zaitcev · « **Reply #17 on:** 04/19/2011 05:12 pm »

The joke "The Chief Designer Got It Right" was factually incorrect. Soyuz was principially a 3-section craft with Living Module (despite Zond), with docking adapter facing up. The configuration presented be Mr. Hudson features a crawl-through Equipment Module, which is reminiscent of TKS, developed by S.P. Korolev's rival, Ac. Chelomei.

HMXHMX · « **Reply #18 on:** 04/19/2011 05:25 pm »

Quote from: clongton on 04/19/2011 04:30 pm

I like what you have done and I have 3 questions.

1. I noticed that during launch the crew is forward facing, and during descent the crew is rearward facing. Is there no pilot station? I ask because I question the need for reorientation. The presentation says the re-entry loading is < 2g's and I don't understand why the seats need to be rotated in that benign environment.

2. Was any design consideration given to the OM actually being a Bigelow inflatable? It looks to be a perfect match.

3. What is the contingency landing mode if the helecopter misses the grab?

Thanks for sharing this.

1) I incorporated our 2005 rotating fabric seat into this design for a couple of reasons. One, it is very lightweight, 10% of an Orbiter middeck seat. Two, it can be stowed while on orbit. Finally, it is very G tolerant in the event of high flight path angle aborts. In such an abort, it can rotate to allow crew to take loads on their backs rather than eyeballs out, such the trajectory demand such a capability.

There is no pilot station. Pilots use handheld multi-function device similar to but more capable than the Soyuz handheld to provide abort commands during ascent, on-orbit docking control and similar functions. They can occupy any seat and also float about the cabin (including into the OM) with the device.

2) It is certainly possible the OM could be replaced by an inflatable for specific missions (say, tourism), but I didn't see any reason to do so at this point, and it would have added another uncertainty to the evaluation.

3) The nominal ISS mission re-entry landing point is set as US West Coast, about 20 KM offshore. This eases FAA permitting. Helos stage from California, and perform the recovery. If they miss, the spacecraft lands in the water, which requires it be rebuilt at the factory. If the capture is successful, it is air-towed (stably, I might add, with high ride comfort unlike capsules) to shore where it is deposited in a cradle for easy crew egress. If it overshoots and comes down on land, the airframe is scrapped, but the crew survives due to the fabric seats. Finally, there is a crew bailout option that extracts the crew on a "stick" with survival gear should the mains become fouled or failed.

HMXHMX · « **Reply #19 on:** 04/19/2011 05:29 pm »

Quote from: zaitcev on 04/19/2011 05:12 pm

The joke "The Chief Designer Got It Right" was factually incorrect. Soyuz was principially a 3-section craft with Living Module (despite Zond), with docking adapter facing up. The configuration presented be Mr. Hudson features a crawl-through Equipment Module, which is reminiscent of TKS, developed by S.P. Korolev's rival, Ac. Chelomei.

Fair enough, if one is being pedantic (which I too have been from time to time, I'll accept). But the main message in both of those Chief Designer's designs is the separation of crew recovery element from that needed on-orbit, without the capability of return. That was my primary point: separation of functions, not numbers of modules.