CCDev to CCiCAP to CCtCAP Discussion Thread

[Brovane]

Dragon V2 has a lot of unknowns but could be landed Soyuz style with parachutes plus rockets.

The biggest unknown about DragonV2 is what might come out of Elon's mouth.  The capsule builds on the DragonV1 which has already been tested multiple times in orbit.  It isn't that radical of design jump. 

[nadreck]

Now there has been reference on the thread here about the use of CST-100 or Dragon V2 as a lifeboat. Does anyone here think that this would be redundant crew return capacity? That is, park a spare capsule over and above the ones that brought passengers? If so would it make sense for that to be a capsule capable of returning the full complement of the station (ie a 7 seat Dragon V2 or CST-100) and maybe one designed to be tested regularly but have a useful shelf life of several years?

There is also a Soyuz lifeboat for the other 3 astronauts. So everyone is covered by a lifeboat.

Yes but at one time there was talk of more than coverage of each astronaut, having an extra crew return vehicle for unforseen events such as taking a crew member off for a medical emergency, or, covering off evacuation in the event of a catastrophe that impacted one of the regular return vehicles. 

[Nindalf]

You do know that Dragon V2 doesn't require propulsive landing to return crew and cargo, right? You keep using the phrase, "extremely ambitious design" for Dragon. It's a capsule, with parachute landing capability, and pusher style abort system, just like the CST-100. While the design includes more ambitious options, they aren't required for it to function.

Unlike the CST-100, the abort system comes down with the crew, and unlike Soyuz, the rockets used to soften the parachute landing are liquid-fuelled with NTO/MMH, and are capable at full throttle of launching the capsule upward at about 6g.  They're certainly capable of boosting it high in the air and wrecking the parachute before hammering the capsule into the ground, wrong-side up.

A pure parachute landing in Dragon V2 is basically meant to be a surviveable crash.  With the big NTO and MMH tanks onboard.  And it's not like they can do an extensive crash test program, as if they were designing a mass-market car.

The possibility that the propulsive landing system / LAS doesn't work as designed isn't equivalent to the case where it's not present.  If it malfunctions, it is capable of destroying the capsule or killing the crew in a variety of ways.

This kind of design will be great if they can dramatically lower launch costs and increase launch availability (both stages reusable), so it can be flight tested extensively like a commercial aircraft, but being able to trust it enough to put people in it after just one unmanned test flight is harder than with a simpler design that has less to go wrong.

[Lars-J]

A pure parachute landing in Dragon V2 is basically meant to be a surviveable crash.  With the big NTO and MMH tanks onboard.  And it's not like they can do an extensive crash test program, as if they were designing a mass-market car.

The possibility that the propulsive landing system / LAS doesn't work as designed isn't equivalent to the case where it's not present.  If it malfunctions, it is capable of destroying the capsule or killing the crew in a variety of ways.

This kind of design will be great if they can dramatically lower launch costs and increase launch availability (both stages reusable), so it can be flight tested extensively like a commercial aircraft, but being able to trust it enough to put people in it after just one unmanned test flight is harder than with a simpler design that has less to go wrong.

This is where the DragonFly test program comes in. There will be a lot of tests before any crewed propulsive landing is made.

It will perhaps never be as thorough as car crash test programs, but they are working on mitigating the risks.

[Nindalf]

This is where the DragonFly test program comes in.

...but what I'm saying is that the DragonFly test program needs to be completed for this system to be trustworthy even with a parachute-assisted landing.

LAS doesn't need to be highly reliable.  If you launch on a 98% reliable rocket, and your LAS is 90% reliable, you have a 99.8% crew survival probability.  Maybe higher, since the rocket can fail in flight and only the parachutes, or even good shock-absorbing seats and a water impact site, need to work for the crew to survive.

Routine landings need to be highly reliable.  Your landing rockets can't blow the capsule up 1% of the time, or you're down under 99% crew survival probability, which isn't good enough by modern standards.  You don't prove that your landing rockets don't kill the crew 1% of the time with a couple of launch aborts, one or two drop tests, and a single unmanned orbital flight.

If things go badly with DragonFly, they're not going to say, "Oh well, we'll just land with parachutes."  It's going to be at least a delay, and maybe a contract cancellation.

[laika_fr]

ISS taxi + tourism + boca chica = Spacex is announcing FH-R here

[Patchouli]

Now there has been reference on the thread here about the use of CST-100 or Dragon V2 as a lifeboat. Does anyone here think that this would be redundant crew return capacity? That is, park a spare capsule over and above the ones that brought passengers? If so would it make sense for that to be a capsule capable of returning the full complement of the station (ie a 7 seat Dragon V2 or CST-100) and maybe one designed to be tested regularly but have a useful shelf life of several years?

There is also a Soyuz lifeboat for the other 3 astronauts. So everyone is covered by a lifeboat.

Yes but at one time there was talk of more than coverage of each astronaut, having an extra crew return vehicle for unforseen events such as taking a crew member off for a medical emergency, or, covering off evacuation in the event of a catastrophe that impacted one of the regular return vehicles. 

Medical emergencies is one of the advantages DC had over the other vehicles because of it's low g reentry and it could land at an airport.

If you land in the boondocks far from a hospital you would be going from the frying pan into the fire.

I'm really surprised Boeing got 4.2 billion dollars while Spacex only got 2.6 billion.

[arachnitect]

Now there has been reference on the thread here about the use of CST-100 or Dragon V2 as a lifeboat. Does anyone here think that this would be redundant crew return capacity? That is, park a spare capsule over and above the ones that brought passengers? If so would it make sense for that to be a capsule capable of returning the full complement of the station (ie a 7 seat Dragon V2 or CST-100) and maybe one designed to be tested regularly but have a useful shelf life of several years?

I suppose that's possible.

The USTV designation is designed to dock on N1 Nadir & N2 Nadir (after PMM relocation). Currently (L2 document) they have only 1-month docked stays shown. However, SpaceX, Orbital, and HTV all use those same two docking ports for cargo, and JAXA plans on providing an additional 2 modules in the future (yay). So it makes it very congested.

I do believe however that there are plans for an additional port? I can't remember 100% though.

edit to add: 'ISS' Pete is the authority on here to figure this stuff out. 

USTV is the CRS2 cargo vehicles. Look for "USCV"

Should be Node 2 Fwd and Node 2 Zenith.

[robertross]

Now there has been reference on the thread here about the use of CST-100 or Dragon V2 as a lifeboat. Does anyone here think that this would be redundant crew return capacity? That is, park a spare capsule over and above the ones that brought passengers? If so would it make sense for that to be a capsule capable of returning the full complement of the station (ie a 7 seat Dragon V2 or CST-100) and maybe one designed to be tested regularly but have a useful shelf life of several years?

I suppose that's possible.

The USTV designation is designed to dock on N1 Nadir & N2 Nadir (after PMM relocation). Currently (L2 document) they have only 1-month docked stays shown. However, SpaceX, Orbital, and HTV all use those same two docking ports for cargo, and JAXA plans on providing an additional 2 modules in the future (yay). So it makes it very congested.

I do believe however that there are plans for an additional port? I can't remember 100% though.

edit to add: 'ISS' Pete is the authority on here to figure this stuff out. 

USTV is the CRS2 cargo vehicles. Look for "USCV"

Should be Node 2 Fwd and Node 2 Zenith.

Ah yes (it was on another document). Thanks for clearing that up

[erioladastra]

But I'm rather surprised and disappointed SNC lost out to Boeing when Dream Chaser is clearly a more capable and innovative then the CST-100.

Innovative can be, and appears to have been, an achilles heel.

I suspect the same since SNC's vehicle was clearly a better vehicle and seemed to have been farther along.

Folks, understandably you don't have all the data.  You cannot make the above statement with any accuracy based on press releases and this message board.  NASA CCP has been carefully reviewing the progress of all 3 partners.  The results were actually not that surprising once you see that NASA was willing to pay for 2 providers.

Kind of defeats the purpose of "commercial crew" though to eliminate one of the innovators and then give the least innovative proposal a significantly higher amount of funding.  But really, I'd rather see CST-100 replace

As I had been trying to say to folks, this was not the intent.  The intent really was access, not new space, not innovation, not beyond NASA commercialization.

[vt_hokie]

I'm really surprised Boeing got 4.2 billion dollars while Spacex only got 2.6 billion.

I'm too cynical to be surprised.  If the goal was simply to get the lowest risk solution to supplementing Soyuz for the few remaining years of ISS life, then it makes sense.  But then we should have just awarded a cost-plus contract years ago, as that's a poor basis for trying to spur an innovative commercial spaceflight revolution.

[Rocket Science]

I'm really surprised Boeing got 4.2 billion dollars while Spacex only got 2.6 billion.

I'm too cynical to be surprised.  If the goal was simply to get the lowest risk solution to supplementing Soyuz for the few remaining years of ISS life, then it makes sense.  But then we should have just awarded a cost-plus contract years ago, as that's a poor basis for trying to spur an innovative commercial spaceflight revolution.

Exactly what I keep saying, I feel like it was a "bait and switch"... So what's the ROI in SNC?

[spectre9]

So does this have anything to do with the decision to axe DC?

http://www.parabolicarc.com/2014/08/19/snc-abandons-hybrid-motors-dream-chaser/

Seems like quite a late change. Calling a new play after the snap really.

[Jim]

I suspect the same since SNC's vehicle was clearly a better vehicle and seemed to have been farther along.

Both untrue and baseless.

[Patchouli]

I'm really surprised Boeing got 4.2 billion dollars while Spacex only got 2.6 billion.

I'm too cynical to be surprised.  If the goal was simply to get the lowest risk solution to supplementing Soyuz for the few remaining years of ISS life, then it makes sense.  But then we should have just awarded a cost-plus contract years ago, as that's a poor basis for trying to spur an innovative commercial spaceflight revolution.

I do feel like it was a bait and switch as it was supposed to have been a fly off where the vehicle with the lowest reoccurring cost wins out.
It still seems too early to be narrowing things down as none of them have flown a pad abort yet.

So does this have anything to do with the decision to axe DC?

http://www.parabolicarc.com/2014/08/19/snc-abandons-hybrid-motors-dream-chaser/

Seems like quite a late change. Calling a new play after the snap really.

A change to a liquid engines may have allowed it to perform reboost if the RCS used the same propellants.

Just over size the forward RCS engines a little and make them able to handle a higher duty cycle.

You wouldn't be performing reboost ops with the main engines anyway.

Burt a change this late also may have cost them the contract as DC seems to be less risky then Dragon V2.

But Dragon V2 does have a huge advantage in that it comes with a LV that does not depend on Russian engines.

[Jim]

But I'm rather surprised and disappointed SNC lost out to Boeing when Dream Chaser is clearly a more capable and innovative then the CST-100.

It wasn't more capable.

I suspect the same since SNC's vehicle was clearly a better vehicle and seemed to have been farther along.

Better based on what? 
Seemed?  no information to support that either

[TomH]

Scott Hubbard opinion piece re. CCtCAP decision on CNN:

http://www.cnn.com/2014/09/16/opinion/hubbard-nasa-space-move/index.html?hpt=hp_bn7

[Oberon_Command]

Jim, in what ways was DreamChaser inferior to CST-100?

[Req]

Jim, in what ways was DreamChaser inferior to CST-100?

You've provided at least one really good answer yourself already.  Bolded text added by me.

[Jim]

Jim, in what ways was DreamChaser inferior to CST-100?

Risk is the only one I know of because I don't have the insight on all the capabilities of both vehicles and that is my point, the posters here don't either.