NASASpaceFlight.com Forum
SLS / Orion / Beyond-LEO HSF - Constellation => Orion and Exploration Vehicles => Topic started by: Chris Bergin on 07/22/2006 09:36 pm
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http://www.nasaspaceflight.com/content/?cid=4659
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I wonder how much of the problem could be solved if they reinstated the LCH4 requirement.
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If this many problems, design changes, and cost overruns had been tolerated on X-33, we'd probably be flying VentureStar by now! ;) Okay, maybe not, but it just goes to show that pretty much any major aerospace program will run into problems, and it's a shame that we cut and run at the first sign of difficulty on X-33, X-34, and others.
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So let me see if this sounds right. In the article it is stated that the CM can be hooked up the the ISS for roughly 7 months, does that mean we will have a 7 man crew finally running the station. It would seem logical at least. 4 for the CM and 3 for the Soyuz. 7 months at a time or staggered shifts so to speak. Anyone in the ISS community know if this might be a plan being considered?
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When you say the CEV CM can support a crew of four for a little more than 2 weeks, what's the limiting factor on that? It seems a bit on the short side considering it doesn't need to rely solely on fuel cells because of the solar wings. Or am I reading it wrong?
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Solar is for electrical power mostly. The amount of O2 they can carry along for instance is a major time limiting factor. RCS fuels I would bet is another as well as other consumables
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vt_hokie - 23/7/2006 12:18 AM
If this many problems, design changes, and cost overruns had been tolerated on X-33, we'd probably be flying VentureStar by now! ;) Okay, maybe not, but it just goes to show that pretty much any major aerospace program will run into problems, and it's a shame that we cut and run at the first sign of difficulty on X-33, X-34, and others.
I agree, and this clearly shows that things can be done if you have a clear direction. X 33 was an experimental research project, there wasn't really a will to build a vehicle, VSE is a national effort with a clear goal and a deadline. this is what made Apollo possible
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Very interesting development and somewhat very fortunate for Lockheed. The design shown in this arictle is very similar to what they have been showing for the past few months.
I wonder what the "Further articles will follow, looking at the CLV (Crew Launch Vehicle) baselines." means. I wonder if there are similar weight saving changes to the CLV or is the entire plan being overhauled. This is pure speculation, but I noticed a new type of Inline derived CLV in the L2 ad above.
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Yeah O2 supply and CO2 removal are probably the limiting factors. Well to start with. It will be interesting to watch how well the new ECLSS on the ISS performs for real.
Also incase I missed it, is there a toilet at all?
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vt_hokie - 22/7/2006 6:18 PM
If this many problems, design changes, and cost overruns had been tolerated on X-33, we'd probably be flying VentureStar by now! ;) Okay, maybe not, but it just goes to show that pretty much any major aerospace program will run into problems, and it's a shame that we cut and run at the first sign of difficulty on X-33, X-34, and others.
All spacecraft and other programs go thru these design cycles. These occure before SRR and PDR. X-33 had them and they then froze the design and then started building it. MSL went thru the same thing. This nothing out of the ordinary for the beginning of a program. You have problems when changes happen after PDR.
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nacnud - 22/7/2006 9:20 PM
Yeah O2 supply and CO2 removal are probably the limiting factors. Well to start with. It will be interesting to watch how well the new ECLSS on the ISS performs for real.
Also incase I missed it, is there a toilet at all?
There's only a predicted mass and size for something called "waste disposal". I guess it remains to be seen whether they specify an actual 'toilet', or leave it up to the contractor. (Whichever, there's certainly not going to be the type of privacy the shuttle has for bathroom breaks.)
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nacnud - 22/7/2006 10:20 PM
Yeah O2 supply and CO2 removal are probably the limiting factors. Well to start with. It will be interesting to watch how well the new ECLSS on the ISS performs for real.
Also incase I missed it, is there a toilet at all?
Don't forget water and food
WCS in the middle of the vehicle on the bottom
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gladiator1332 - 22/7/2006 10:16 PM
Very interesting development and somewhat very fortunate for Lockheed. The design shown in this arictle is very similar to what they have been showing for the past few months.
NG and Boeing are doing the same thing. There is no advantage to either team.
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gladiator1332 - 23/7/2006 3:16 AM
I wonder what the "Further articles will follow, looking at the CLV (Crew Launch Vehicle) baselines." means. I wonder if there are similar weight saving changes to the CLV or is the entire plan being overhauled. This is pure speculation, but I noticed a new type of Inline derived CLV in the L2 ad above.
This all started off with information that the 5 seg stick first stage had hit a critical problem - and there's a list of them. We've been going back and fourth on this with sources and engineers on L2 (hell of a thread), but incidentially we bumped into the July 21 DAC-2 CEV presentation, so obviously that got the priority to be run first.
We're still going back and fourth on the CLV, with an article to come. So that's what I meant :)
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vt_hokie - 22/7/2006 6:18 PM
If this many problems, design changes, and cost overruns had been tolerated on X-33, we'd probably be flying VentureStar by now! ;) Okay, maybe not, but it just goes to show that pretty much any major aerospace program will run into problems, and it's a shame that we cut and run at the first sign of difficulty on X-33, X-34, and others.
Read Dennis Jenkins' book on the STS. How many changes were there to the "final" configuration that they chose? They aren't problems.
The other programs were into production.
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I got a good design change...Put on some wings, wheels, a cockpit, and voila!!!
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Shuttle>CEV - 22/7/2006 10:26 PM
I got a good design change...Put on some wings, wheels, a cockpit, and voila!!!
And voila! An obese, stuck-in-earth-orbit, useless piece of outdated technology!
Seriously, wings and wheels would add absolutely nothing of any practical value to the CEV...
Simon ;)
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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.
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simonbp - 23/7/2006 2:10 AM
Shuttle>CEV - 22/7/2006 10:26 PM
I got a good design change...Put on some wings, wheels, a cockpit, and voila!!!
And voila! An obese, stuck-in-earth-orbit, useless piece of outdated technology!
Seriously, wings and wheels would add absolutely nothing of any practical value to the CEV...
Simon ;)
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.
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I love the Space Shuttle. I love it so much that I'm willing to let my social life go down the drain by constantly being on the Internet to read up on the latest news about STS-115 and the remaining shuttle flights (just joking... sort of).
But if going back to the traditional rocket design help ensures that we don't have another in-flight disaster a la Challenger and Columbia (especially considering we have had NO crew losses with traditional rockets outside of Apollo 1...in which the tragedy took place 'on the ground'), and have this new generation learn what it was like to live the days of the moon landings (Me being part of this new generation), then I'm all for the capsule CEV.
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 ;)
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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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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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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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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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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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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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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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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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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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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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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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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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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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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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If this design can achieve all the mission requirements, why did NASA previously specify a larger vehicle?
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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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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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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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Neither. Define bloated. Lift off mass is 27.6t, injected mass is 22.0t, effect mass 23t
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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?
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mr.columbus - 23/7/2006 3:11 AM
There is enough space in a 4.5m diameter CEV to accomodate a crew of 4 for Moon missions (or ISS missions, if any).
L2 has 3D drawings of the crew seated in the CEV, filled with ony minimal equipment. It is EXTREMELY cramped. If anything, NASA should try to build the biggest capsule it reasonably can.
mr.columbus - 23/7/2006 3:11 AM
The 23t effective mass in LEO mentioned above is the CEV mass after the new design changes, is it?
Yes, after changes.
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deltaV remains same? it would be shame to give up the capability to land everywhere on surface
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imfan - 23/7/2006 6:37 PM
deltaV remains same? it would be shame to give up the capability to land everywhere on surface
The LSAM does plane changes for landing anywhere on the moon, not the CEV. All the deltaV the CEV is responsible for is orbit circul. and TEI.
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The land everywhere capability is a function of the LSAM not the CEV.
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I know that landing and arive are jobs for LSAM but landing the crew without return has no point. and thats the part for CEV. LSAM+CEV arive in a plane that is suitable for desired landing site, but during 14day stay it is possible that CEVs orbit plane will be out of reach af ascending module which implies that CEV has to have some plane change capability. and to ensure anytime return there is a need to make up to 90 degrees plane change and that is a quite demanding maneuver requiring even more dV than TEI(from idelal inclination) itself
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Jim - 23/7/2006 3:43 PM
Neither. Define bloated. Lift off mass is 27.6t, injected mass is 22.0t, effect mass 23t
By bloated I meant "had it grown heavier than the original spec" or "had it grown too heavy for the launcher", etc. In other words, is this reduction making it lighter than originally planned, or is it merely shaving excess that accumulated during the initial design phase to get it back down to where it was originally supposed to be? The numbers you list make me think that the latter may be the answer.
- Ed Kyle
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mr.columbus - 23/7/2006 6:01 PM
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.
How do you know the 4.5 m is enough. 6 man requirement is also a ISS requirement.
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edkyle99 - 23/7/2006 4:41 PM
Jim - 23/7/2006 3:43 PM
Neither. Define bloated. Lift off mass is 27.6t, injected mass is 22.0t, effect mass 23t
By bloated I meant "had it grown heavier than the original spec" or "had it grown too heavy for the launcher", etc. In other words, is this reduction making it lighter than originally planned, or is it merely shaving excess that accumulated during the initial design phase to get it back down to where it was originally supposed to be? The numbers you list make me think that the latter may be the answer.
- Ed Kyle
ESAS launch mass: 27.3 tonnes
ESAS on orbit mass: 23.1 tonnes
ESAS SPS net delta v: 1.7 km/s
DAC2 launch mass: 27.0 tonnes
DAC2 on orbit mass: 22.0 tonnes
DAC2 SPS net delta v: 1.8 km/s
And there you have it: the difference between a 90-day "rough draft" and nearly a year of real engineering...
Simon ;)
(Note: my "launch mass" doesn't count the adapter b/c ESAS doesn't have it)
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Also interesting to see lots more RCS and something a little closer to the Canfield joint on the solar arrays.
http://www.nasaspaceflight.com/content/?cid=4182
They are going to need a new video ;)
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Jim - 23/7/2006 7:41 PM
mr.columbus - 23/7/2006 6:01 PM
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.
How do you know the 4.5 m is enough. 6 man requirement is also a ISS requirement.
I don't know if 4.5 m is enough, I assume that (i) if 5m is a comfortable size for a crew of 6 and (ii) 3.7 m was comfortable for a crew of 3 with Apollo then 4.5 m is comfortable for a crew of 4. A 6-man ISS requirement is strange anyway, (i) we might see as few as 2-3 ISS flights by a CEV between 2014 and 2016 and (ii) it is not contemplated that Soyuz will go out of service before the ISS project end, so no need to carry 6 people to the ISS or have a lifeboat capability of 6 (+ I always thought that the CEV will carry only 3 astronauts to the ISS anyway).
What I am saying is, the more the mass of the CEV gets reduced the better. You open up new launcher possibilities with a mass well under 20t and can shift the same mass to the LSAM which in turn can sustain longer sortie-missions on the Moon.
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5m isn't comfortable for the crew, it doesn't quite meet the requirements
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I have to agree that I think a 5m CEV is going to be a bit stuffy for a 4-person crew to the moon, but they will have the LSAM docked for extra "living space" while en route back and forth. It it probably the bare minimum size that can do the job for 4 people.
5m doesn't seem scalable to a 6-person ISS transfer vehicle, though. I'm guessing that requirement will have to be revised for the 5m sizing.
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I don't know for sure but I think that the LSAM assent module is to be ditched before departing the Moon.
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Was the Delta II second-stage engine (AJ10-118K) "always" intended as the CEV's injection engine? I thought they were trying to steer clear of NTO/MMH. So the stack-up of engines is:
1st stage: 4/5-segment SRB
2nd Stage: J-2x (restart capable)
Injection Motor: AJ10? (restart capable)
Has that list changed since the switch from RS-25x?
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nacnud - 24/7/2006 10:09 AM
I don't know for sure but I think that the LSAM assent module is to be ditched before departing the Moon.
I think you're right, now that you mention that. It'll be like a road trip in a Ford Festiva on the way back. ;)
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"2nd Stage: J-2x (restart capable)"
??? what is this good for?
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Which bit, the restart bit? The restart is needed as I think the Earth departure stage is used as a kick stage for the LSAM + EDS to get into a stable LEO. It is then restarted once the CEV has docked for the Earth departure burn.
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imfan - 24/7/2006 12:14 PM
"2nd Stage: J-2x (restart capable)"
??? what is this good for?
The J-2x for the CLV will likely not have any restart hardware installed in it, not necessary since for the CLV it needs to burn only once. (The J2's on the Saturn V second stage also did not have restart hardware installed). The J-2x for the CaLV on the other hand needs restart. First burn will but the LSAM and EDS into proper orbit, the second burn will send it off to the moon.
-Jim
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yeah... need for restart is obvious for CaLV. I only thought we were discussing CLV
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Might be worth nothing this is an ongoing process, and given the savings they've been able to make some other changes on top, with one just now.
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Jim - 23/7/2006 8:19 AM
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"?
Remember back in the 70's when the shuttle was viewed as the be all end all spacecraft? Well, now they are doing the same thing to the CEV and they are under the impression that a capsule is somehow safer. Apollo didn't last long enough to have a major disaster, but if the program went longer, I guarantee you it would've had a disastrous loss.
Also, Columbia & Challenger could've easily been prevented, NASA had PLENTY of warnings before that and had ample time to fix them..they didn't. And no mention of the 2 Soyuz losses? But wait, that can't be, the capsule is like the greatest thing ever..*rolleyes*
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Shuttle>CEV - 25/7/2006 6:15 PM
Also, Columbia & Challenger could've easily been prevented, NASA had PLENTY of warnings before that and had ample time to fix them..they didn't. And no mention of the 2 Soyuz losses? But wait, that can't be, the capsule is like the greatest thing ever..*rolleyes*
Logical fallacy here is that those 2 Soyuz capsules were not lost BECAUSE they were capsules.
Columbia and Challenger would have been survivable events if they were not side-mounted. If you put a winged spacecraft ON TOP then its a differant story. (although for CEV you get into some debatable issues regarding reentry at much higher velocities etc...)
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What about if your parachute fails to deploy on your capsule? You're pretty much a projectile going straight into the ground at Mach speeds, and you have no control of it like you would with a shuttle during re-entry.
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Shuttle>CEV - 25/7/2006 4:54 PM
What about if your parachute fails to deploy on your capsule? You're pretty much a projectile going straight into the ground at Mach speeds, and you have no control of it like you would with a shuttle during re-entry.
Exact same as if any of the numerous hydrulic components (like the ailerons, flaps, landing gear, etc.) on the shuttle fail; the amount of single-point failures possible with a runway-landing is mind boggling...
Again, there is not real benfit to a runway landing (=wings)...
Simon ;)
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What if your APUs fail in the shuttle, your pretty much a brick from that point onwards.
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capsules slow down bellow M1 even before opening chutes(not that it would matter wether U hit ground in M1 or M0.5) . there are usually multiple chutes. these chutes are usually of the circle type(not sure what is the right name for it) which are very reliable.
this weekend we had a small party on airfield and I have been talking to the guy who is responsible for packing pilot chutes and he told me story from different airfield. Pilot needed to jump once and however his chute hadnt been checked and repacked for 8 years(well it is not really according to rules :-) ) and this chute had been used for all that 8 years(during which may people sit on that, the chute had been brought many times from plane to store and back)... this chute opened
thats for chute reliabily and I am sure chutes at NASA will get much more care
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I am not particularly knowledgable about these things but I ran across this :
"One of the really scary things about NASA's CEV plans for lunar exploration is that they plan to use the same aerodynamic skip technique developed by the Russians in the 1960's to return to US territory after a re-entry over the south pole. The problem with this approach is how you recover the capsule in the vast southern oceans if the guidance fails and it has to make a ballistic re-entry at the first entry interface. This preoccupied Russian planners a lot in the 1960's, leading to enormous estimates for the size of the naval and airborne recovery forces that would have to be arrayed along the re-entry path stretching a quarter of the way across the earth through the most remote oceans imaginable."
Here http://astronautix.com/Mambo/ - 2006/05/26 Sounds spooky to me. Is there anyone that can address this?
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simonbp - 25/7/2006 7:18 PM
Shuttle>CEV - 25/7/2006 4:54 PM
What about if your parachute fails to deploy on your capsule? You're pretty much a projectile going straight into the ground at Mach speeds, and you have no control of it like you would with a shuttle during re-entry.
Exact same as if any of the numerous hydrulic components (like the ailerons, flaps, landing gear, etc.) on the shuttle fail; the amount of single-point failures possible with a runway-landing is mind boggling...
Again, there is not real benfit to a runway landing (=wings)...
Simon ;)
Yes, but once you reach a certain speed, you can bail out of the shuttle. How do you get out of a capsule????
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No need to bailout, back up parachutes. Bail out of the shuttle only works under Mach 1. A capsule is safer. there are less parts, better abort scenarios, easier TPS, passive entry (or something close to it).
Response to earlier post: the CEV does have a manuvering entry. If the control system fails, then it has a ballistic entry. Shuttle does not have a backup to RCS, APU, HYD failure
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I think that's something that some of us younger readers worry about, paracutes. We're so used to a winged lifting body being there and getting them home. Dropping and hoping the paracutes open scares me, but I assume these things don't fail historically like on the Soyuz and back ups are good (actually didn't know about that).
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one problem with a capsule, if you want more interior space, you need to make it wider, which means a wider booster. other shapes you can make LONGER.
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Hail, both would require a new vehicle. elongating a capsul into a cylinder/capsule is as easy as making a winged body longer.
some things are simply shaped for a very good reason.
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well I was more talking about the "apollo" shape, as it is the rule for the CEV.
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HailColumbia - 25/7/2006 7:25 PM
one problem with a capsule, if you want more interior space, you need to make it wider, which means a wider booster. other shapes you can make LONGER.
Longer, especially high L/D bodies would only allow for side-mount (CG placement, ascent control issues if top-monted with no shroud) which in turn would disable abort modes, preclude use of externally insulated cryo stages, complicate stacking, be more expensive and labor intensive. It's a catch-22. With current propulsion methods high l/d is a pain in the rear during ascent as well. To solve this you need to go horizontal take-off as well. Which in turn swings back to basic propulsion (rockets are more efficient taking off vertical)
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HailColumbia - 25/7/2006 10:25 PM
one problem with a capsule, if you want more interior space, you need to make it wider, which means a wider booster. other shapes you can make LONGER.
There is no rule that says a capsule can't be wider than the launch vehicle. Payload fairings more times that not are wider that the LV.
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Lots of small planes (with wings, and even engines) have parachutes nowadays - to land the plane safely if anything goes wrong. They save lives. Parachutes are a reliable and safe system.
Sure, they can go wrong. What can't? But, it's a question of probabilities, and the probability of a fatal failure is lower for parachutes.
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A soyuz paracute did fail once I remember. Killed all on board.
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Martin FL - 26/7/2006 7:56 AM
A soyuz paracute did fail once I remember. Killed all on board.
Bad design hurried into production and into flight
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Martin FL - 26/7/2006 1:56 PM
A soyuz paracute did fail once I remember. Killed all on board.
it was soyuz 1 . in this case it means that there was only Vladimir Komarov onboard. Killed all is quite misleading. that flight was prepared in a great hurry under political preasure. whole flight experienced lot of trouble. I think those chutes failed because they werent preheated because lack of power which was consequence to solar panel deployment failure
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For a really good detailed explanation of the Soyuz failure (and BTW- "all" aboard was a single cosmonaut) read Alexi Leonov's take on it in "Two Sides of the Moon" by Toomey. It is the side-by-side stories of Dave Scott and Leonov and although both men's stories are terrific- Leonov's accounts of what went on on the other side are really great and highly detailed.
IMO- These arguments against the CEV in favor of some space plane that is not even close to development are really shot sighted. It seems that every time I read one it can be replaced with "bring back the Dyan Soar" and "My favored vehicle will have a zero failure rate" not to mention the fact that they seem to believe political (i.e. FUNDING) winds will always blow favorably- even in the gap. CEV critics also seem to think that no government contractor will ever run over budget. When the fact is that rarely do government contracts not overrun their budget. Can you imagine where we'd be if these same critics had watched the Grumman contract on the LEM under the same microscope as they watch the CEV?
Here's my take on it- The CEV is going to keep us flying in space... PERIOD! And so far as "The Vision" goes, remember that, other than those few people who have hands-on the tip of the arrow of space exploration, for the public and humanity at large, spaceflight is more about inspiration than exploration. That is it's true value.
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zerm - 26/7/2006 8:23 AM
Here's my take on it- The CEV is going to keep us flying in space... PERIOD! And so far as "The Vision" goes, remember that, other than those few people who have hands-on the tip of the arrow of space exploration, for the public and humanity at large, spaceflight is more about inspiration than exploration. That is it's true value.
Totally agree.
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I like all things Human spaceflight related. one of my hopes is that the CEV (Block 1 or 2) will be able to do some near earth exploration as well as lunar exploration. There are many interesting physics experiments and investigations to be done at several points between earth and moon. I'd love to see something like a CEV + ATV rendezvous and then several little investigations of the neat places between earth and moon. Perhaps, maybe I’m too being silly, but I would like to be on a mission that had a highly elliptical orbit and could fling itself in and out of the various parts of the magnetosphere. (with proper protection of course.)
And before 2003, I had hoped that Columbia or Atlantis would have their Payload bays filled with a new, larger space lab and perhaps an irrationally overcomplicated additional fuel reserve to do long range high orbit missions… essentially turning a shuttle into a mini, retrievable, reusable space station. But, some dreams make better dreams than realities.
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Those type missions do not require a man.
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HailColumbia - 25/7/2006 9:25 PM
one problem with a capsule, if you want more interior space, you need to make it wider, which means a wider booster. other shapes you can make LONGER.
Interior spaced is not a problem for a capsule. A capsule is, or should be, designed to do one job well - crew protection during ascent and atmospheric reentry for the least mass (meaning smallest heat shield). Extra interior space, if needed, can be added by docking the capsule to an additional lightweight, non-heatshielded module (or modules) in orbit (hello, Bigelow?). For ISS missions, CEV's "module" is ISS. For lunar missions it is LSAM.
- Ed Kyle
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Jon_Jones - 26/7/2006 5:52 PM
I like all things Human spaceflight related. one of my hopes is that the CEV (Block 1 or 2) will be able to do some near earth exploration as well as lunar exploration. There are many interesting physics experiments and investigations to be done at several points between earth and moon. I'd love to see something like a CEV + ATV rendezvous and then several little investigations of the neat places between earth and moon. Perhaps, maybe I’m too being silly, but I would like to be on a mission that had a highly elliptical orbit and could fling itself in and out of the various parts of the magnetosphere. (with proper protection of course.)
And before 2003, I had hoped that Columbia or Atlantis would have their Payload bays filled with a new, larger space lab and perhaps an irrationally overcomplicated additional fuel reserve to do long range high orbit missions… essentially turning a shuttle into a mini, retrievable, reusable space station. But, some dreams make better dreams than realities.
If you are interested in magnetospheric physics you need a magnetically clean vehicle so that the highly sensitive magnetometers can operate undistrurbed. CEV will never be suitable for that. Far better to use specifically designed umanned experiments like Cluster.
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zerm - 26/7/2006 11:23 AM
IMO- These arguments against the CEV in favor of some space plane that is not even close to development are really shot sighted.
By contrast, my opinion is that to be cheap now in developing our next generation spacecraft will cost us dearly in the long run. The arguments for the CEV seem to me to be very short sighted. Yeah, a simple capsule launched on existing launch vehicle hardware might be easier and cheaper up front than something ambitious like a next generation RLV, but it will ensure that we continue to spend billions of dollars a year on a handful of flights. At what point do we decide to stop stagnating, and get on with the next stage of technology development?
Here's my take on it- The CEV is going to keep us flying in space... PERIOD!
Barely. If we're going to spend billions of taxpayer dollars on 1960's style spaceflight, perhaps leading to a couple of feel good flag and footprints missions to the moon more than a decade down the road, I don't see how the cost can possibly be justified. If we revived programs like X-33 today, we could be doing a lot more in space by the time 2020 rolls around.
And so far as "The Vision" goes, remember that, other than those few people who have hands-on the tip of the arrow of space exploration, for the public and humanity at large, spaceflight is more about inspiration than exploration. That is it's true value.
Sorry, but I don't find replacing the amazing space shuttle with a glorified Apollo capsule to be very inspiring.
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The Venturestar (not X-33) couldn't lift shuttle class payloads. So in 2020, we would be stuck using components for spacecraft smaller than the current ISS components. Addtionally, the Venturestar was to be unmanned.
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Jim - 26/7/2006 4:59 PM
The Venturestar (not X-33) couldn't lift shuttle class payloads. So in 2020, we would be stuck using components for spacecraft smaller than the current ISS components.
Actually, I recall that VentureStar was intended to have a roughly 50,000 lb payload capacity to LEO. But obviously, a scaled up, orbital version of X-33 was not realistic. However, a fully reusable two stage system is a logical follow-on to STS.
Addtionally, the Venturestar was to be unmanned.
Initially, but crewed versions were to have followed.
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So some would rather we go into another post-Apollo six year gap with a concept vehicle that needs a change in the laws of physics just to work? Then that gap turns into a decade while the vote-grubs in the congress chip away at the the NASA budget to build bridges to nowhere... yeah... that's a vision for space explorin'. I stand on what I said before- history will decide. Meanwhile, I plan to be at KSC to watch the SDLVs roll out and fly. Others may feel more comfortable sitting at home watching those computer graphics of the X-33 over, and over. ;)
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zerm - 26/7/2006 5:24 PM
Others may feel more comfortable sitting at home watching those computer graphics of the X-33 over, and over. ;)
I have a model of X-33 sitting on my desk, as a matter of fact! It's a reminder of what might have been, with better leadership.
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vt_hokie - 26/7/2006 5:33 PM
zerm - 26/7/2006 5:24 PM
Others may feel more comfortable sitting at home watching those computer graphics of the X-33 over, and over. ;)
I have a model of X-33 sitting on my desk, as a matter of fact! It's a reminder of what might have been, with better leadership.
Actually, it is where it should be, as a model. The leadership did the right thing and cancelled it vs dumping more $ into it.
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I sell flying model kits of the Ares I. Reminds me that the future looks pretty cool... errr... provided they put the fins back on that is ;)
I just sprayed the first stage of the my Ares V prototype kit... but I swore I would not put that into production until NASA stops changing the darned thing! Seems like every time they put out a press release these days it looks different. Until this month it was one size from top of the thrust structure to the nosecone- so I had 50 nosecones custom milled in that size- then they scaled down the upper stage! Sheeeesh :(
Of course if I just wait... they'll change it again.
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So, again, I'll ask this question: At what point is the time right to stop stagnating and start moving forward with technology development again? 20 years from now? 40? 100?
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Just because it looks a bit like Apollo from the outside doesn't mean that it Apollo in the inside. There will be massive technology development in the Constellation program.
Can you please stop going on and on and on about it.
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Indeed, I'm sure the CEV critics would be singing a different tune if the next vehicle were the Max Faget "DC-3" short cross range orbiter on the full return fly-back booster- a concept that is 35 years old.
The CEV and the Ares I have some very exciting aspects that many overlook in their haste to arm-chair critic the program. The coming LES test flights are a good example. (I'm one who hopes they call those flights "Little Joe III"). A lot will be confirmed and learned and it will be really cool to see an unattached single SRB launched down the range. The CEV is the development of a whole new vehicle and system... and THAT inspires.
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vt_hokie - 26/7/2006 6:57 PM
So, again, I'll ask this question: At what point is the time right to stop stagnating and start moving forward with technology development again? 20 years from now? 40? 100?
The same time trains lose their wheels and use maglev.
It isn't stagnating. Let the market find a cheaper vehicle. NASA doesn't have the flight rate. The EELV's, Protons and Ariane are keeping you employed, so there must be a business model for ELV's that works.
NASA is more in the spacecraft and exploration than tech development
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Jim - 26/7/2006 8:01 PM
The same time trains lose their wheels and use maglev.
So, now in other words? ;) Just because the U.S. is stagnant on maglev doesn't mean other nations are. You can ride a 270 mph maglev train in China, as a matter of fact! :) (Of course, the Chinese merely paid the Germans to build it for them.)
The EELV's, Protons and Ariane are keeping you employed, so there must be a business model for ELV's that works.
You have a point, I suppose! But human spaceflight won't become accessible to the masses until we have RLV's to make that happen.
NASA is more in the spacecraft and exploration than tech development.
Maybe we need two agencies, then - one for aerospace research and development, and another for operations.
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vt_hokie - 26/7/2006 7:44 PM
Maybe we need two agencies, then - one for aerospace research and development, and another for operations.
Strictly speaking, in the US, there are already at least four launch vehicle R&D organisations: Lockheed Martin, Boeing, Orbital, and SpaceX... :)
Seguing a bit, that's why I'm not supprised that NASA aero research is being cut; most of it is airliner-focused, which in reality means the only real benefactors are Boeing's shareholders. Government work is good at two things, low-level technology development (something at least 5 years from the marketplace) and not-for-profit operations (like space exploration). If the "alt.space industry" wants to start making a profit, they need to start exploiting that gap more fully; COTS allows this, but it will only work long-term if it is actually competitive...
Simon ;)
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"If we're going to spend billions of taxpayer dollars on 1960's style spaceflight, perhaps leading to a couple of feel good flag and footprints missions to the moon more than a decade down the road, I don't see how the cost can possibly be justified."
I keep seeing this phrase: "Flags and footprints", coming from critics of the VSE. I find that a little dishonest, a bit like a mudslinging political slogan that is repeated over and over again in the hopes that it will become one of those "everyone knows" statements that gains a life of its own.
Apollo 11 may have been a "flags and footprints" mission, with two astronauts spending less than three hours walking on the surface. The later Apollo missions had the two astronauts performing three EVAs of about 6-8 hours each, and covering a lot more territory.
If the ESAS Lunar program survives in spite of its opponents, the INITIAL mission should more than double the EVA time of the last Apollo. The capability to land in a wider variety of locations is also not to be sneered at, unless you are one of those who believe there is no scientific or other reason to go back to the Moon, in which case you'll be very happy if the program folds.
But let's get one thing straight. If ESAS is shot down, the United States is not going to be building an X-something miracle whiz-bang SSTO toy for a VERY long time. The only American manned presence in space will be the occasional purchased seat on a Soyuz or such, and tourists taking sub-orbital hops on Rutan's SS2. The space program has many political opponents, and they want that money for other things.
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darkenfast - 27/7/2006 8:08 PM
I keep seeing this phrase: "Flags and footprints", coming from critics of the VSE. I find that a little dishonest, a bit like a mudslinging political slogan that is repeated over and over again in the hopes that it will become one of those "everyone knows" statements that gains a life of its own.
But let's get one thing straight. If ESAS is shot down, the United States is not going to be building an X-something miracle whiz-bang SSTO toy for a VERY long time. The only American manned presence in space will be the occasional purchased seat on a Soyuz or such, and tourists taking sub-orbital hops on Rutan's SS2. The space program has many political opponents, and they want that money for other things.
You are SOOOO RIGHT!!! Unlike you, some people just don't see the big picture; they are so full of their own sarcasm, negativity and not-invented-here mentality. Sheesh... :(
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vt_hokie - 26/7/2006 10:44 PM
You have a point, I suppose! But human spaceflight won't become accessible to the masses until we have RLV's to make that happen.
Whose says the masses need access at this time.? If they want they can find their own way. It not NASA's job. Just like the westward expansion of the US.
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yes but in the expansion, the settlers only needed horses and that is not high tech, just kidding ;)
I would go even further: human spaceflight won't be accessible to the masses in the foreseeable future, not even an RLV can make that happen. we are limited by the laws of physics, chemistry, materials science, ....
and baring some huge "scientific breakthrough" that allows us to create rocket engines with both massive ISP and thrust that are at least as safe as current airplane's reactors and ecologically friendly, it will not happen.
prices can be lowered but it will never be cheap, right now the quest for such systems is a wild goose chase.
and NASA, in fact, in choosing a destination rather than a vehicle, is creating a market, because once they are on the moon, and they want to set up their base, resupply it, make crew rotation, etc.. they are going to need more affordable space access, they will become a customer with a need, and then successful spaceflight ventures like spaceX (who will be mature enough by 2018) will be able to provide those services, creating more affordable medium to heavy lift capabilities, the same thing will happen for mars, and beyond, each time creating a market and pushing the technology.
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simonbp - 26/7/2006 11:51 PM
[
Seguing a bit, that's why I'm not supprised that NASA aero research is being cut; most of it is airliner-focused, which in reality means the only real benefactors are Boeing's shareholders. Government work is good at two things, low-level technology development (something at least 5 years from the marketplace) and not-for-profit operations (like space exploration). If the "alt.space industry" wants to start making a profit, they need to start exploiting that gap more fully; COTS allows this, but it will only work long-term if it is actually competitive...
Simon ;)
I've often thought that aeronautics research should go either to the DoD or the FAA. I know, I know the old NACA boys would be rolling in their grave.
Earth observing sats should be in the realm of NOAA or the USGS or some other agency. This would include any "Mission to Planet Earth" plans that NASA has a hand in. Private contractors could and should be launching these spacecraft.
Unmanned probes would be in the realm of Caltech/JPL or Hopkins/APL. Universities could and should have greater autonomy over probes.
Then NASA could be known as the National Council on Astronautics. In the year 2001, a certain NCA employee named Dr. Heywood Floyd would discover an anomaly on crater Tycho... ;)
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zerm - 26/7/2006 5:50 PM
I sell flying model kits of the Ares I. Reminds me that the future looks pretty cool... errr... provided they put the fins back on that is ;)
I just sprayed the first stage of the my Ares V prototype kit... but I swore I would not put that into production until NASA stops changing the darned thing! Seems like every time they put out a press release these days it looks different. Until this month it was one size from top of the thrust structure to the nosecone- so I had 50 nosecones custom milled in that size- then they scaled down the upper stage! Sheeeesh :(
Of course if I just wait... they'll change it again.
Just an FYI, it wasn't the upper stage that was scaled down, it was the lower stage that was scaled up.
-Jim
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Gene DiGennaro - 27/7/2006 11:03 AM
Earth observing sats should be in the realm of NOAA or the USGS or some other agency. This would include any "Mission to Planet Earth" plans that NASA has a hand in. Private contractors could and should be launching these spacecraft.
Unmanned probes would be in the realm of Caltech/JPL or Hopkins/APL. Universities could and should have greater autonomy over probes.
These two areas are just as much "exploration" as the VSE and equal level in NASA's Charter. NASA is NOT manned spaceflight! And God forbid that it doesn't change.
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Jim - 27/7/2006 10:49 AM
Gene DiGennaro - 27/7/2006 11:03 AM
Earth observing sats should be in the realm of NOAA or the USGS or some other agency. This would include any "Mission to Planet Earth" plans that NASA has a hand in. Private contractors could and should be launching these spacecraft.
Unmanned probes would be in the realm of Caltech/JPL or Hopkins/APL. Universities could and should have greater autonomy over probes.
These two areas are just as much "exploration" as the VSE and equal level in NASA's Charter. NASA is NOT manned spaceflight! And God forbid that it doesn't change.
I'll agree with you on the second part. I was a bit premature. I'll revise my plan and allow NASA to be in charge of unmanned vehicles to OTHER planets. Earth observing should be in the realm of other agenices or organizations.
Gene
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vt_hokie - 26/7/2006 10:44 PM
Jim - 26/7/2006 8:01 PM
The same time trains lose their wheels and use maglev.
So, now in other words? ;) Just because the U.S. is stagnant on maglev doesn't mean other nations are. You can ride a 270 mph maglev train in China, as a matter of fact! :) (Of course, the Chinese merely paid the Germans to build it for them.)
But maglevs are STILL shaped like trains! I demand they add wings! Now THAT would be progress...
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Moved to CEV.