CCDev-2 Finalists

[baldusi]

... Which we still need to send, since we are essentially "buying" two Soyuz per year for crew escape capability for the non-russian crew.

I guess you just don't get it.  Not sure how I could have been much more clear.  Oh well. 

I'm intrigued, was the original plan to keep a permanent shuttle on ISS and relieve it with another one? Can the ISS dock two shuttles? How would crew rotation have been implemented then?

[Robotbeat]

... Which we still need to send, since we are essentially "buying" two Soyuz per year for crew escape capability for the non-russian crew.

I guess you just don't get it.  Not sure how I could have been much more clear.  Oh well. 

I'm intrigued, was the original plan to keep a permanent shuttle on ISS and relieve it with another one? Can the ISS dock two shuttles? How would crew rotation have been implemented then?

No, I believe the original plan was to have a CRV of some sort. But those keep getting canceled.

[Namechange User]

... Which we still need to send, since we are essentially "buying" two Soyuz per year for crew escape capability for the non-russian crew.

I guess you just don't get it.  Not sure how I could have been much more clear.  Oh well. 

I'm intrigued, was the original plan to keep a permanent shuttle on ISS and relieve it with another one? Can the ISS dock two shuttles? How would crew rotation have been implemented then?

No.  I've explained this many times.  Shuttle does crew rotation, meaning up and down.  The Russians fly Soyuz, two remain docked at all times for crew escape.  Open seats on the Soyuz can be used for the "spaceflight participants", just like has been done in the past.

The fact is the US government is funding the construction of one of these vehicles per year instead of the Russian government.  That was because we cancelled the X-38 nearly a decade ago.  The fact of the matter is that the US will now have to pay Russia more for transportation, training, etc for American, European, Japanese and Canadian crews as this was the job of the United States.

This is like the fifth time I have made this statement.  I'm can't explain it any better.  If people still don't understand, well I'm sorry. 

[simonbp]

The original plan was for a Crew Rescue Vehicle (CRV) to be permanently at the station. X-38 was the design chosen for CRV, but it was canceled at the same time as the US habitation module at the start of Bush Administration. This was replaced Soyuz as CRV as an interim until Orbital Space Plane (OSP) was ready. OSP became CEV became Orion. As Orion got pushed back further (and became MPCV), a stripped-down Orion as a CRV was part of Obama's budget last year, but seems to have gone away...

[Joris]

But that doesn't cover the on-orbit and reentry phases, where Shuttle is way more mature then any new system.

cheers, Martin

I LOL'd so hard at this statement. Since when is the shuttle TPS "more mature" than a capsule?

You seem to have quite the misunderstanding of orbiter TPS and want to blame it as the root of everything, even when the statement you responded to didn't even mention TPS. 

Shuttle has quite a lot of room for improvement.
PICA is better than the Carbon-Carbon matrix.

Even though a shuttle is more advanced than any capsule currently in development, its also far more complex.
This adds more difficulties, and thus maintence and cost.

Complexity isn't always good, there is a trade-off.

[Lars_J]

Shuttle has quite a lot of room for improvement.
PICA is better than the Carbon-Carbon matrix.

PICA is ablative, which doesn't work so well for a shuttle-type vehicle.

[Joris]

PICA is ablative, which doesn't work so well for a shuttle-type vehicle.

PICA-x is capable of dozens, if not hundreds of reuses. That should be enough to do the job.

[Lars_J]

PICA is ablative, which doesn't work so well for a shuttle-type vehicle.

PICA-x is capable of dozens, if not hundreds of reuses. That should be enough to do the job.

Having ablative material smeared over a large part of the fuselage is not great for a vehicle that hopes to be reusable with minimal work. For a winged vehicle with a large surface area this is even more true.

Dragon re-use (if it happens) will probably involve re-applying the outer sidewall insulation. The heat shield could be reused, but expect it will not be. It makes more sense for SpaceX to reduce excess margin by thinning the heat shield, to allow more payload. Want to fly it again? - Put a new heat shield on it.

Different protective materials are useful for different purposes.

[mlorrey]

But that doesn't cover the on-orbit and reentry phases, where Shuttle is way more mature then any new system.

cheers, Martin

I LOL'd so hard at this statement. Since when is the shuttle TPS "more mature" than a capsule?

You seem to have quite the misunderstanding of orbiter TPS and want to blame it as the root of everything, even when the statement you responded to didn't even mention TPS. 

I am quite familliar with the Orbiter TPS. Its immaturity and stillborn status (i.e. the decision to cut the tile size rather than investing in resolving cracking issues early on) is, along with the segmented SRB design, and the decision to cease painting and sealing the tank foam, the three main design flaws in the launch system that contribute to its uneconomic operation and its high risk rating.

Shuttle has always been an experimental vehicle pressed into operational service by egotism. It is not by any means "mature". A mature technology by definition is one which is maximised for economic operation, inherently safe to operate, capable of frequent operation without major overhauls or complete rebuilds between each use.

[Joris]

Having ablative material smeared over a large part of the fuselage is not great for a vehicle that hopes to be reusable with minimal work.

But the the opposite of minimal work is needed for the Shuttle TPS.

[Chris Bergin]

Having ablative material smeared over a large part of the fuselage is not great for a vehicle that hopes to be reusable with minimal work.

But the the opposite of minimal work is needed for the Shuttle TPS.

Wroooooooong.

You've not been keeping up with the state the orbiters have been returning in. Most of the TPS work is related to chips coming off the SLF at landing, and then it's a handful, of what is tens of thousands.

Let's keep the misinformation down please.

[Namechange User]

But that doesn't cover the on-orbit and reentry phases, where Shuttle is way more mature then any new system.

cheers, Martin

I LOL'd so hard at this statement. Since when is the shuttle TPS "more mature" than a capsule?

You seem to have quite the misunderstanding of orbiter TPS and want to blame it as the root of everything, even when the statement you responded to didn't even mention TPS. 

I am quite familliar with the Orbiter TPS. Its immaturity and stillborn status (i.e. the decision to cut the tile size rather than investing in resolving cracking issues early on) is, along with the segmented SRB design, and the decision to cease painting and sealing the tank foam, the three main design flaws in the launch system that contribute to its uneconomic operation and its high risk rating.

Shuttle has always been an experimental vehicle pressed into operational service by egotism. It is not by any means "mature". A mature technology by definition is one which is maximised for economic operation, inherently safe to operate, capable of frequent operation without major overhauls or complete rebuilds between each use.

Ok, thanks.  How's that F-104-in-space coming?

[Jim]

1.  I am quite familliar with the Orbiter TPS. Its immaturity and stillborn status (i.e. the decision to cut the tile size rather than investing in resolving cracking issues early on) is,

2. along with the segmented SRB design,

3. and the decision to cease painting and sealing the tank foam, the three main design flaws in the launch system that contribute to its uneconomic operation and its high risk rating.

You are working with old and out dated data, in addition to error fulled  conclusions from lack of knowledge.

1.  Far from it.  The TPS work between missions is down by more than a magnitude and is a minor portion of the flight turnaround work

2.  Monolithic solids were not viable

4. Painting the tank would not prevent foam loss

[Jorge]

1.  I am quite familliar with the Orbiter TPS. Its immaturity and stillborn status (i.e. the decision to cut the tile size rather than investing in resolving cracking issues early on) is,

2. along with the segmented SRB design,

3. and the decision to cease painting and sealing the tank foam, the three main design flaws in the launch system that contribute to its uneconomic operation and its high risk rating.

You are working with old and out dated data, in addition to error fulled  conclusions from lack of knowledge.

1.  Far from it.  The TPS work between missions is down by more than a magnitude and is a minor portion of the flight turnaround work

2.  Monolithic solids were not viable

4. Painting the tank would not prevent foam loss

Beat me to it! Jim is correct, as usual.

[Robotbeat]

mlorrey, educate yourself about Shuttle (why the heck does every single conversation here revolve around Shuttle?):
http://ocw.mit.edu/courses/aeronautics-and-astronautics/16-885j-aircraft-systems-engineering-fall-2005/lecture-notes/
Watch ALL of those.

[mlorrey]

1.  I am quite familliar with the Orbiter TPS. Its immaturity and stillborn status (i.e. the decision to cut the tile size rather than investing in resolving cracking issues early on) is,

2. along with the segmented SRB design,

3. and the decision to cease painting and sealing the tank foam, the three main design flaws in the launch system that contribute to its uneconomic operation and its high risk rating.

You are working with old and out dated data, in addition to error fulled  conclusions from lack of knowledge.

1.  Far from it.  The TPS work between missions is down by more than a magnitude and is a minor portion of the flight turnaround work

2.  Monolithic solids were not viable

4. Painting the tank would not prevent foam loss

1. As of 2001, NASA was reporting that 75% of all maintenance man hours between flights involved TPS maintenance. Unless there has been an unreported miracle or two since then, my point stands. As of 2004, MMH per flight totalled 44,000+, which, while reduced from that typical of the 1990's, was still more than ten times greater rate on average, in MMH/FH than any other reusable aerospace vehicle.

Granted, in the old days, the TPS workers would spit in the tile adhesive so it would not dry as fast (the batches of glue would harden by the time you applied 2 or 3 tiles), a practice that was undocumented and put to an end when NASA officials found out about it, but it also meant that the adhesive was weaker and thus tiles were more prone to fall off in flight.

As for your claim that MMH has gone down, I just saw a press release on STS-131 claiming that United Space Alliance puts 750,000 MMH into the flow for each shuttle turnaround, which is actually almost ten times more maintenance time than NASA claimed when they did the work themselves. The PR may be wrong, but getting recent maintenance data is neigh on impossible for the public these days, compared to the past.

2. Monolothic solids were viable and tested on two occasions, and were also cheaper and manufactured in Florida. The ATK segmented design only won due to congressional influence, as it was heavily criticized at the time for the risks inherent with segementing.

3. Simple experiment any idiot can perform:
   i. throw a sponge into a tank of water, see it soak up water and sink.
   ii. paint a sponge. let it dry, throw it in the tank, see it float high in the water.

Painting the tank foam would limit the ability of air to ingress into the foam when air already in the foam is being frozen by the chilling of fuelling of the tanks. This would limit ice formation. It would not eliminate ice formation, but it would limit the mass of ice formed.

The SAIT report in 2000 clearly stated: "SSP maintenance and operations must recognize that the Shuttle is not an 'operational'
vehicle in the usual meaning of the term."

[Jim]

1. As of 2001, NASA was reporting that 75% of all maintenance man hours between flights involved TPS maintenance. Unless there has been an unreported miracle or two since then, my point stands. As of 2004, MMH per flight totalled 44,000+, which, while reduced from that typical of the 1990's, was still more than ten times greater rate on average, in MMH/FH than any other reusable aerospace vehicle.

1.  a.  Granted, in the old days, the TPS workers would spit in the tile adhesive so it would not dry as fast (the batches of glue would harden by the time you applied 2 or 3 tiles), a practice that was undocumented and put to an end when NASA officials found out about it, but it also meant that the adhesive was weaker and thus tiles were more prone to fall off in flight.

1.b As for your claim that MMH has gone down, I just saw a press release on STS-131 claiming that United Space Alliance puts 750,000 MMH into the flow for each shuttle turnaround, which is actually almost ten times more maintenance time than NASA claimed when they did the work themselves. The PR may be wrong, but getting recent maintenance data is neigh on impossible for the public these days, compared to the past.

2. Monolothic solids were viable and tested on two occasions, and were also cheaper and manufactured in Florida. The ATK segmented design only won due to congressional influence, as it was heavily criticized at the time for the risks inherent with segementing.

3. Simple experiment any inaccurate can perform:
   i. throw a sponge into a tank of water, see it soak up water and sink.
   ii. paint a sponge. let it dry, throw it in the tank, see it float high in the water.

Painting the tank foam would limit the ability of air to ingress into the foam when air already in the foam is being frozen by the chilling of fuelling of the tanks. This would limit ice formation. It would not eliminate ice formation, but it would limit the mass of ice formed.

1.  Provide the 2001 report. 

1.a  Source please.  Again, pre Challenger ancient data
1,b  NASA never did the work themselves.  USA workers were previously badged as LSOC.

2.  Wrong
a.  The tests were not 100% successful
b.  There is no data to base cheaper on
c.  The logistics for getting the monolithic solids to the pad were never solved. 

3.  That is not the foam loss mechanism.  The air does not freeze and form ice.  See cryopumping.  Paint would not help with cracks from tank shrinkage

[MP99]

But that doesn't cover the on-orbit and reentry phases, where Shuttle is way more mature then any new system.

cheers, Martin

I LOL'd so hard at this statement. Since when is the shuttle TPS "more mature" than a capsule?

NASA's current all-of-mission PRA for Shuttle is 1:89. That's better than 1:11 chance of safely completing 10 consecutive missions.

I'd be surprised if the coming commercial systems can truly match that all-of-mission risk over their first 10 crewed flights.

cheers, Martin

[yamato]

PICA is ablative, which doesn't work so well for a shuttle-type vehicle.

PICA-x is capable of dozens, if not hundreds of reuses. That should be enough to do the job.

Having ablative material smeared over a large part of the fuselage is not great for a vehicle that hopes to be reusable with minimal work. For a winged vehicle with a large surface area this is even more true.

Dragon re-use (if it happens) will probably involve re-applying the outer sidewall insulation. The heat shield could be reused, but expect it will not be. It makes more sense for SpaceX to reduce excess margin by thinning the heat shield, to allow more payload. Want to fly it again? - Put a new heat shield on it.

Different protective materials are useful for different purposes.

this discussion is useless. Ablatives work differently than heat soak TPS. Ablatives are designed to work under certain heat conditions, under which the ablation works and takes the heat away. In other words, if the vehicle doesnīt heat up enough, the shield doesnīt work. Ceramic TPS absorbs the heat, which means it works always, but it has limited heat soak capacity. Shuttle has ceramic TPS, because it is designed to fly only to LEO, and the heat loads on reentry are relatively low. Dragon is designed to moon-reentry, with heat loads so high, that heat soak TPS would hardly do the job, but ablative PICA-X does it easily.
So itīs not a question of personal preference or ease of reuse. The physical requirements are different.

[Calorspace]

Does anyone know the latest regarding when an announcement is set to be made on the awards?