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#20
by
HKS
on 23 Jul, 2006 12:08
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punkboi - 23/7/2006 10:24 AM
If it works, stick with it. Yes, the Space Shuttle works...but 14 lives lost means it's more sensible to go back to that "stupid capsule" design 
Lives will be lost in the "stupid capsule" design too, It already has happend in Russia, and in the USA, and only luck prevented it on Apollo 13 to. I will not be suprised if a disaster strikes the CEV to. Remember, we are pushing thechnology far here!
I my opinion, a capsule design is probably for now, the way to go to get people to the moon and mars, but for LEO access it's a step back. And posibility to use have reaserch in LEO, like on the ISS is very usefull. It's still ALOT to learn about long duration space flights.
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#21
by
Jim
on 23 Jul, 2006 13:32
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Shuttle>CEV - 23/7/2006 3:32 AM
Seriously, it is going to suck when these stupid capsules are again in service. No distinction, not nearly as capable, and they WILL bite NASA in the ass. Let's enjoy these final years of the shuttle, we're gonna need it.
How will it suck?
Who cares about distinction. I hope the CEV is not reusable so they don't get names that everyone gets wrapped up about. Just serial and mission numbers would be fine. Just like the X-15.
How will they will they "bite NASA in the ass"? It is not as though the shuttle hasn't (twice). The capabilities of the shuttle have been overprescribed and not needed (except for downmass).
What are we are "gonna need"?
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#22
by
Jim
on 23 Jul, 2006 13:35
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HKS - 23/7/2006 7:55 AM
Lives will be lost in the "stupid capsule" design too, It already has happend in Russia, and in the USA, and only luck prevented it on Apollo 13 to. I will not be suprised if a disaster strikes the CEV to. Remember, we are pushing thechnology far here!
No new technology will be used. It is being designed to prevent accidents. If anything does go wrong, it will be because of an outside influence vs a design shortfall
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#23
by
Jim
on 23 Jul, 2006 13:37
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mr.columbus - 23/7/2006 3:11 AM
Whatever the technical reasons for the changes are, a reduction in CEV mass is a good thing - saves money and gives more margin elsewhere. The mass shed off the CM is one step forward, I am however dissapointed that they did not push that a little bid more, reduce the capsule diameter to 4.5 metres and shed another .5-1mt off of it - that would push overall mass (with the according mass reduction on the SM) to well below 20tons. Launcher options would suddenly appear in a complete other light.
Any further reductions in the CEV size will make it unable to meet the requirements imposed on it.
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#24
by
Norm Hartnett
on 23 Jul, 2006 14:49
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Well this is disappointing. I'd been hearing the rumors and was hoping for good news.
First we had "Apollo on steroids" then we had "Apollo on a good workout regime" and now we have "Apollo that jogs once a week".
Jim
Any further reductions in the CEV size will make it unable to meet the requirements imposed on it.
I would assume they will simply change the requirements. Coming soon "Gemini on steroids".
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#25
by
punkboi
on 23 Jul, 2006 15:12
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Jim - 23/7/2006 6:19 AM
How will they will they "bite NASA in the ass"? It is not as though the shuttle hasn't (twice).
Any reply to this other than "Touché" would be inaccurate
HKS - 23/7/2006 4:55 AM
Lives will be lost in the "stupid capsule" design too, It already has happend in Russia, and in the USA, and only luck prevented it on Apollo 13 to. I will not be suprised if a disaster strikes the CEV to. Remember, we are pushing thechnology far here!
Of course you shouldn't be surprised. Hence the cliche, "Human spaceflight is risky business."
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#26
by
Jim
on 23 Jul, 2006 15:21
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Norm Hartnett - 23/7/2006 10:36 AM
Well this is disappointing. I'd been hearing the rumors and was hoping for good news.
First we had "Apollo on steroids" then we had "Apollo on a good workout regime" and now we have "Apollo that jogs once a week".
I would assume they will simply change the requirements. Coming soon "Gemini on steroids".
Why the sarcasm
It is still on steriods. 5m is still larger than 3.7m Apollo. The exact size is not the driving requirement. The 4 man lunar mission and I see nothing that prevents that. So what if the women and smaller men have to sit on the outboard sits for ISS missions.
If it now carries less in the unmanned version, then your COTS may be more viable.
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#27
by
zinfab
on 23 Jul, 2006 15:31
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Does the further reduction in size jeopardize the ESAS requirement for the CEV to spend up to 6 months awaiting the return of the LSAM from the surface of the moon?
The Orion SM looks TINY compared to the Apollo SM, now. With volume reductions, I just get concerned about losing flexibility.
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#28
by
Jim
on 23 Jul, 2006 15:42
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zinfab - 23/7/2006 11:18 AM
Does the further reduction in size jeopardize the ESAS requirement for the CEV to spend up to 6 months awaiting the return of the LSAM from the surface of the moon?
The Orion SM looks TINY compared to the Apollo SM, now. With volume reductions, I just get concerned about losing flexibility.
It is 1.3m or so wider than Apollo, that in itself makes it shorter. The document showed that it still met the 6 month requirement. Remember the SM doesn't have to brake into lunar orbit and it doesn't carry H2 and O2 and fuel cells.
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#29
by
hyper_snyper
on 23 Jul, 2006 15:48
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Jim - 23/7/2006 11:29 AM
zinfab - 23/7/2006 11:18 AM
Does the further reduction in size jeopardize the ESAS requirement for the CEV to spend up to 6 months awaiting the return of the LSAM from the surface of the moon?
The Orion SM looks TINY compared to the Apollo SM, now. With volume reductions, I just get concerned about losing flexibility.
It is 1.3m or so wider than Apollo, that in itself makes it shorter. The document showed that it still met the 6 month requirement. Remember the SM doesn't have to brake into lunar orbit and it doesn't carry H2 and O2 and fuel cells.
Just a quick question if I may. No fuel cells
at all on the CEV?
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#30
by
MKremer
on 23 Jul, 2006 15:50
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hyper_snyper - 23/7/2006 10:35 AM
Just a quick question if I may. No fuel cells at all on the CEV?
You've got those nice, big solar panels and rechargable batteries, why would you need fuel cells?
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#31
by
hyper_snyper
on 23 Jul, 2006 15:53
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MKremer - 23/7/2006 11:37 AM
hyper_snyper - 23/7/2006 10:35 AM
Just a quick question if I may. No fuel cells at all on the CEV?
You've got those nice, big solar panels and rechargable batteries, why would you need fuel cells?
Yeah I know, you're right. But for some reason I think I remember reading that it would have fuel cells for redundancy. I must have misread.
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#32
by
simonbp
on 23 Jul, 2006 15:58
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Jim - 23/7/2006 8:29 AM
It is 1.3m or so wider than Apollo, that in itself makes it shorter. The document showed that it still met the 6 month requirement. Remember the SM doesn't have to brake into lunar orbit and it doesn't carry H2 and O2 and fuel cells.
Right, as the LSAM will the Lunar Orbit Insertion burn, the only things the main engine on the CEV is used for is Earth orbit circularisation after ascent (like Shuttle OMS) and the Trans-Earth Injection burn to leave the moon (oh, and retro for ISS missions), and both could probably be done by the RCS system, if nessicery...
Remember also, mass savings on the CEV not only have knock-on effects on the CLV, but also on the LSAM/EDS complex, and thus on the CaLV. An ounce saved on the CEV might mean a pound saved on the LSAM/EDS, which might mean 20 pounds saved on the CaLV...
Simon
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#33
by
Chris Bergin
on 23 Jul, 2006 16:20
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I've heard various ration figures, but one major source notes it's 9:1, so 6,500 shaved off the top end equals extra margin of 58,000lbs of extra margin IF used to translate into the first stage booster, which they will use, one assumes, given the first stage is five figures over on allowances.
Still doesn't solve the problems noted with the 5 seg stick (opposing views to that too), so this will run on.
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#34
by
Ctrl.Alt.Del.
on 23 Jul, 2006 18:21
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If this design can achieve all the mission requirements, why did NASA previously specify a larger vehicle?
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#35
by
simonbp
on 23 Jul, 2006 18:47
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Ctrl.Alt.Del. - 23/7/2006 11:08 AM
If this design can achieve all the mission requirements, why did NASA previously specify a larger vehicle?
They didn't specify a larger vehicle, they just made a first guess, and since engineers tend to be hyper-conservative about such things, they guessed on the higher end. Spacecraft aren't quite designed every other day, so the engineers need a rough initial guess that they can then tweak and fiddle with until it works...
Simon
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#36
by
Jim
on 23 Jul, 2006 19:11
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Ctrl.Alt.Del. - 23/7/2006 2:08 PM
If this design can achieve all the mission requirements, why did NASA previously specify a larger vehicle?
Because that was the first estimate.
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#37
by
edkyle99
on 23 Jul, 2006 20:47
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Does this reported 3 tonne reduction mean that CLV will now only need to boost 22 tonnes instead of 25 tonnes, or is this a reduction from a bloated initial design to get mass back down to 25 tonnes?
- Ed Kyle
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#38
by
Jim
on 23 Jul, 2006 20:56
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Neither. Define bloated. Lift off mass is 27.6t, injected mass is 22.0t, effect mass 23t
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#39
by
mr.columbus
on 23 Jul, 2006 22:14
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Jim - 23/7/2006 9:24 AM
mr.columbus - 23/7/2006 3:11 AM
Whatever the technical reasons for the changes are, a reduction in CEV mass is a good thing - saves money and gives more margin elsewhere. The mass shed off the CM is one step forward, I am however dissapointed that they did not push that a little bid more, reduce the capsule diameter to 4.5 metres and shed another .5-1mt off of it - that would push overall mass (with the according mass reduction on the SM) to well below 20tons. Launcher options would suddenly appear in a complete other light.
Any further reductions in the CEV size will make it unable to meet the requirements imposed on it.
As far as I see it the only requirement that might suffer by a further reduction of size is the CEV's capability to be used for Mars missions as a return capsule for a 6-men crew - a requirement as unnecessary as planning an Airbus 320 cockpit in the 1980s with a requirment in mind to fit it into a 2006 Airbus 380.
There is enough space in a 4.5m diameter CEV to accomodate a crew of 4 for Moon missions (or ISS missions, if any). If there is CM equipment that would fit only into a 5m CEV and not in a 4.5m CEV, I would like to know what that is. A CEV with a mass under 20t would be a major improvement to NASA's plans in my opinion, as I said earlier it helps a lot on the development of the CLV and also gives more leeway on the CaLV and LSAM.
The 23t effective mass in LEO mentioned above is the CEV mass after the new design changes, is it?
