CCDev to CCiCAP to CCtCAP Discussion Thread

[Lurker Steve]

If it's the difference between only having one crew provider and having two, it makes far more sense to combine crew and cargo. Not only does it share costs, but it also greatly increases safety, since a randomly introduced design/process problem is more likely to be caught on a non-life-critical cargo flight than a crew flight.

Not true. A manufacturing defect could occur on either the crew or cargo mission, which would shut down both crew and cargo flights from that provider until it was resolved. Since the frequency of the CRS flights isn't that much greater than the manned missions, the problem could occur on either mission. Just go back to the problem with the Russian upper stages if you need an example of why 2 different providers are needed.

[Lars_J]

I believe Elon said at a talk or during an interview not too long ago that crew Dragon would not have a trunk and solar panels but instead just have way bigger batteries.

You got it part right. No solar panels, yes, but the trunk will likely remain, even if it is in a shortened form.

[Lars_J]

CST-100 could probably work just as good as a Dragon, with a CBM, and a new service module.

No, there is no space for the larger CBM hatch on the CST-100. The area around the hatch is where all the parachutes are packed (just like Orion and Apollo) - There just isn't room without a significant re-design.

The large hatch is part of the reason for the lower parachute placement of Dragon.

[mlindner]

I believe Elon said at a talk or during an interview not too long ago that crew Dragon would not have a trunk and solar panels but instead just have way bigger batteries.

You got it part right. No solar panels, yes, but the trunk will likely remain, even if it is in a shortened form.

Partly right again. The solar panels are gone yes, but it was _unspecified_ what will happen to the trunk. Everything beyond that is guess work.

[Lars_J]

I believe Elon said at a talk or during an interview not too long ago that crew Dragon would not have a trunk and solar panels but instead just have way bigger batteries.

You got it part right. No solar panels, yes, but the trunk will likely remain, even if it is in a shortened form.

Partly right again. The solar panels are gone yes, but it was _unspecified_ what will happen to the trunk. Everything beyond that is guess work.

They didn't talk about warp drive either, so it remains an option? If it is unspecified, one should assume no change - until new evidence is brought forward.

[Lobo]

They might have, but now they are quite focused on providing crew services. And even NASA had to think a lot about what they meant by man rating. All this has generated a very specific and custom designs.
CST-100 could probably work just as good as a Dragon, with a CBM, and a new service module. In fact, they seem to have almost all their RCS save the pusher escape system on the sides, so they might have thought about it.
Dream Chaser, seems more designed for Crew. A CBM doesn't seems to fit there, and the length and width might pose quite an interference problem if it were modified for being handled. And I can't see how to add unpressurized module. I mean, they could add a whole MLPM besides the DC, but it would block the propulsion modules. I ignore about Blue Origin's New Space Vehicle, but it doesn't seems to have a a way to put a CBM, since the NDS was on the side. Ironically, ATK's Liberty had the best proposal for cargo. Although I doubt it's cost and maturity.
But all of them have been designed and optimized for crew at this stage. That means having a pilot do the approach and docking. It's also the reason you have to put a CBM. I don't think NASA would allow automatic docking to the APAS-like on the USOS side. So now they would have to design all the new avionics and approaching software, plus the ISS interaction to get in the grapple box. And now there's no COTS money.
But the true issue is the LV. You don't use Atlas V because it's cheap, you use it because it's as reliably a LV as they come (which is important way more important for crew than for cargo). The New World Observatory papers stated that an Atlas V 501 cost 140M. Take in consideration that costs have gone up dramatically, and those where 2007 prices. What's more, these vehicles use the Centaur x 2, which uses two of the most expensive item on the Atlas V, the RL10. I would not be surprised if the 402 is about 170M today. Which is more than the whole Dragon mission. And each Cygnus mission costs 190M. There's one way to compete with them. But that would require to use a 431, or find a way to use a 551 (which would need a custom "fairing" upto the capsule adapter). Then you make a big craft that can double the payload of either Cygnus or Dragon. So you can compete on USD/kg. But that would mean half the missions and bigger spacecraft, too.
The other issue of optimizing for cargo (launching on Atlas V) is that you have to put a lot of volume, while optimizing for crew you worry about evacuation, ECLSS, etc. After they did a low of optimizing for crew, retrofitting cargo gets more difficult.

 

Yea, I think CST-100 would be similar to Dragon in being able to provide crew and pressurized cargo service.  Put a CBM in place of the docking hatch.   Put a trunk on it in place of the LAS and you have unpressurized cargo too.
And yea, DC is probably more problematic to make cargo as it’s more optimized for crew.  But it might not be as bad as one might think with a little creative thinking.  As far as a CBM, you might be able to have one that can be jettisoned affixed to the aft, with an adaptor that allows DC to be berthed like Dragon is.  So that it doesn’t need to be docked by a pilot.  After the mission, that fixture is jettisoned and DC returns to Earth remotely. 
This could be a whole aft “trunk” fixture that attaches to the aft of a cargo DC (so it’s design would be a little different than the crew DC).  This trunk has the CBM on it.  Sort of like the concepts  for the HL-42.

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=8079.0;attach=179947;image

Except that would have a CBM on it.
Now, the obvious issue would be DC’s hybrid rocket engines.  Something like that would interfere with them.   However, there are ways possibly around that.  First, maybe cargo DC gets rid of them?  It instead launches on an Atlas with a single engine Centaur, but with several SRB’s.  Basically Centaur does the full orbital insertion then without requiring DC to do it.  Like the Falcon upper stage does for Dragon and like Centaur will do for CST-100.  Why not?  Can DC’s RCS system deorbit it without requiring a powerful retro burn?  Dragon and CST-100 will deorbit themselves with the RCS system won’t they?   Can DC do that?  IF not, perhaps this trunk fixture can have a retro pack of some kind.  Just something simple that does the retro burn that is jettisoned with the trunk/CBM.  Add more SRB’s on the Atlas for more upmass on DC-cargo if needed.

So I think there’s ways to do it.  It would require a DC modified for it, but SNC could just build a Cargo-only variant of DC, and reuse it with a new trunk each time for cargo missions…which they’d probably want to do anyway because it wouldn’t need the ECLSS and HMI and other crew provisions, to free up cargo room and mass.
Would that be any more problematic than the CST-100 SM or Dragon trunk that are jettisoned each mission?

[Lar]

I believe Elon said at a talk or during an interview not too long ago that crew Dragon would not have a trunk and solar panels but instead just have way bigger batteries.

I remember hearing that, oops.

But maybe I'm not totally convinced that is how things will end up. He may have been misquoted or they may change their mind. But if that's how it comes out then ya

Nevertheless IF a trunk remains, and IF there is mass available, it might be a possibility. But probably not one to design for I guess.

[Robotbeat]

If it's the difference between only having one crew provider and having two, it makes far more sense to combine crew and cargo. Not only does it share costs, but it also greatly increases safety, since a randomly introduced design/process problem is more likely to be caught on a non-life-critical cargo flight than a crew flight.

Not true. A manufacturing defect could occur on either the crew or cargo mission, which would shut down both crew and cargo flights from that provider until it was resolved. Since the frequency of the CRS flights isn't that much greater than the manned missions, the problem could occur on either mission. Just go back to the problem with the Russian upper stages if you need an example of why 2 different providers are needed.

I was referring to safety, not schedule impact. You only addressed schedule impact, as if knowing about a safety problem (and thus having to stop flights until it is fixed) is worse than not knowing about it... For /real/ levels of safety, it's much better to find out about the problem. CRS flights should be about 3 times more frequent than crew flights, so if the vehicles are largely the same, you have just one fourth as great of a chance of the problem first rearing its head on the crewed flight. That's a pretty good improvement!

And as far as schedule impact... That's a good reason to have two crew providers!!!

[Lar]

And as far as schedule impact... That's a good reason to have two crew providers!!!

... who don't use the same launch vehicle. As cool as it might be to put DC on F9 instead of Atlas (might be cheaper too) It's probably not a good idea from that aspect.

[Robotbeat]

And as far as schedule impact... That's a good reason to have two crew providers!!!

... who don't use the same launch vehicle. As cool as it might be to put DC on F9 instead of Atlas (might be cheaper too) It's probably not a good idea from that aspect.

Agreed.

[tnphysics]

And as far as schedule impact... That's a good reason to have two crew providers!!!

... who don't use the same launch vehicle. As cool as it might be to put DC on F9 instead of Atlas (might be cheaper too) It's probably not a good idea from that aspect.

Unless DC can be made LV agnostic. Then it could fly on either.

[Robotbeat]

And as far as schedule impact... That's a good reason to have two crew providers!!!

... who don't use the same launch vehicle. As cool as it might be to put DC on F9 instead of Atlas (might be cheaper too) It's probably not a good idea from that aspect.

Unless DC can be made LV agnostic. Then it could fly on either.

Or perhaps nominally on F9 but optionally on man-rated Delta IV...

[joek]

And as far as schedule impact... That's a good reason to have two crew providers!!!

... who don't use the same launch vehicle. As cool as it might be to put DC on F9 instead of Atlas (might be cheaper too) It's probably not a good idea from that aspect.

Unless DC can be made LV agnostic. Then it could fly on either.

Nothing inextricably binding DC to Atlas, unless you discount the time and money for integration and test, which would be a do-over for another LV (emphasis added)...

Our launch system is the Atlas V, although we're agnostic, we can launch on anything that can lift our mass ... we chose the Atlas because it has the capacity to do what we do, but mainly because it has a long history...

Also, remember that NASA is funding an integrated capability, not piece parts.  If DC loses in the next rounds, it's highly unlikely there will be money for them to complete development, let alone qualify on a different LV.

[dcporter]

If DC loses in the next rounds, it's highly unlikely there will be money for them to complete development, let alone qualify on a different LV.

I recall SN saying that they intended to continue pursuing it, albeit more slowly?

[Zed_Noir]

Wonder if SpaceX and Boeing might each do a test launch of the other's capsule on their respective LVs?

Then any future hiccups with the LVs and capsules with not halt access to space.

[Lars_J]

Wonder if SpaceX and Boeing might each do a test launch of the other's capsule on their respective LVs?

Then any future hiccups with the LVs and capsules with not halt access to space.

Why? Not unless NASA pays for it. While it can be done, it will cost $$$ to develop the adapter, and do the wind tunnel work to verify the configuration. It isn't just plug-n-play.

[mr. mark]

"Space Exploration Technologies (SpaceX) continues to work with NASA on plans for a Dragon pad abort test at Cape Canaveral Air Force Station's Space Launch Complex 40. The test will help the company assess the spacecraft's integrated launch abort system, parachutes and supporting avionics. Throughout NASA's human spaceflight endeavors, pad abort tests have played an important role in evaluating the ability of a spacecraft's launch abort system to get an astronaut crew to safety in the event of an emergency on the launch pad".

http://www.nasa.gov/exploration/commercial/crew/index.html

[mr. mark]

While it still is TBD, Glad to see it coming up on the launch calendar.

(2015) "4th quarter - TBD, ABS 2A - Falcon 9 v1.1 - Canaveral SLC-40
yearend - Dragon  (manned flight to ISS) - Falcon 9 v1.1 - Canaveral SLC-40"

http://forum.nasaspaceflight.com/index.php?topic=8184.msg1025272#msg1025272

[Jason1701]

While it still is TBD, Glad to see it coming up on the launch calendar.

(2015) "4th quarter - TBD, ABS 2A - Falcon 9 v1.1 - Canaveral SLC-40
yearend - Dragon  (manned flight to ISS) - Falcon 9 v1.1 - Canaveral SLC-40"

http://forum.nasaspaceflight.com/index.php?topic=8184.msg1025272#msg1025272

That would probably be the second manned Dragon flight, right? The first would have SpaceX crew and not be on NASA's launch schedule.

[erioladastra]

Wonder if SpaceX and Boeing might each do a test launch of the other's capsule on their respective LVs?

Then any future hiccups with the LVs and capsules with not halt access to space.

CST-100 is being designed to work on Atlas or F9.