Orion (CEV / SM) - status

cIclops · 2008-04-16 10:40:28

Besides the improved aerodynamics, the big advantage of the new LAS is that it allows the capsule to save mass by reducing the maximum loads during an abort. Preliminary analysis shows (PDF) that the new LAS increases payload by 545 kg.

gaetanomarano · 2008-04-16 14:54:57

Preliminary analysis shows that the new LAS increases payload by 545 kg.

it's not the LAS (that's is similar to the Apollo LES) but due to the more aerodynamic BPC shape

also, there is no better and more aerodynamic tower-LAS than... NO tower-LAS... and (you may like it or not) MY underside-LAS is the most aerodynamic possible (also more than a MLAS) since it's completely HIDDEN inside the SM fairing!

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gaetanomarano · 2008-04-16 15:02:44

Every pound that can be transferred from capsule to LAS saves several pounds of capsule mass.

that's true, but there is no extra-pounds they can transfer from capsule to LAS... if you refer to the underside-LAS, well, it will be jettisoned exactly like the tower-LAS

And nobody is ever going to use the "underside LAS" because bolting anything to the heat shield is a terrible idea, and there would be too much equipment protruding into the service module.

as already explained in my articles and posts (that, clearly, you've not read) about the underside-LAS, it is NOT joined to the TPS but to the TPS protection cover (or structure) between the TPS and the SM

of course, the SM and the SM fairing need a different design to host the underside-LAS

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GCNRevenger · 2008-04-16 18:44:03

Preliminary analysis shows that the new LAS increases payload by 545 kg.
it's not the LAS (that's is similar to the Apollo LES) but due to the more aerodynamic BPC shape
also, there is no better and more aerodynamic tower-LAS than... NO tower-LAS... and (you may like it or not) MY underside-LAS is the most aerodynamic possible (also more than a MLAS) since it's completely HIDDEN inside the SM fairing!

Wrong

The tower actually lowers drag, by permitting the rest of the rocket to "hide" under the low-pressure region generated by the tip of the LAS tower. For example, the Trident-II ballistic missile:

The reason why other launch vehicles don't use this is because they are satellite launchers, and dumping the faring early like Ares-I does (along with the LAS tower) would probably subject the satellite to too much high-speed air. Or, at the least, increase complexity.

GCNRevenger · 2008-04-16 19:00:30

that's true, but there is no extra-pounds they can transfer from capsule to LAS... if you refer to the underside-LAS, well, it will be jettisoned exactly like the tower-LAS

Huh? The biggest structural load, and hence how sturdy and heavy it has to be, would be due to the aerodynamic pressures of launch. Eliminating these pressures permits a lighter capsule, how is this hard to grasp?

Your dumb underside LAS idea is ridiculous, numerous abort motors mean increased risk of deadly failure right next to the crew or else knocking the capsule into an unrecoverable spin. They are also much too small unless you use an unrealistic number of them, and their small size leads to them having much more casing mass for either the tower LAS or MLAS system. And last but not least, the extra explosive bolts, wiring, and...

...oh yeah because the capsule is the same diameter as the rest of the Ares-I, your stupid underside LAS motors would HIT THE ROCKET when they are jettisoned as the SM faring would have to taper to a smaller diameter than the capsule in order to to tuck under the LAS motors, so you can eject them before reaching orbit. Your idea is awful.

Edit: Oh, and looking at your terrible design with the SM faring being much smaller than the capsule, where do the solar panels go?

gaetanomarano · 2008-04-17 08:58:52

The tower actually lowers drag, by permitting the rest of the rocket to "hide" under the low-pressure region generated by the tip of the LAS tower. For example, the Trident-II ballistic missile

as you've already said, 99% of rocket launch have no "tower" not even the most launched spacecraft of the story: the Shuttle

also the Gemini was launched without a tower and with (also) a truncated-cone capsule top

however, assuming a "tower" may help, it doesn't need to be so BIG and 7+ mT heavy like the Orion LAS, but just a small and very light tower like the Trident pin

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gaetanomarano · 2008-04-17 09:05:55

...numerous abort motors mean increased risk of deadly failure...

no, since, despite it's four nozzles, the LAS has a single motor, and this single motor can fail, while, if one of the 6+ motors oif the underside-LAS fails, the Orion may have a sligtly curved trajectory, but the astronauts are saved

...the capsule is the same diameter as the rest of the Ares-I...

but the SM is smaller, so, there is enough space for the underside-LAS

...your terrible design...

it's only one of dozens possible designs

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GCNRevenger · 2008-04-17 15:07:31

as you've already said, 99% of rocket launch have no "tower" not even the most launched spacecraft of the story: the Shuttle
also the Gemini was launched without a tower and with (also) a truncated-cone capsule top
however, assuming a "tower" may help, it doesn't need to be so BIG and 7+ mT heavy like the Orion LAS, but just a small and very light tower like the Trident pin

Shuttle doesn't have one because the main tank and not the orbiter is at the tip of the whole vehicle, and it doesn't have an ejectable faring to place an aerospike on top of plus has the LO2 fill port. And as I said before with satellite launchers, they probably need to keep their faring to a higher altitude to protect the fragile satellite, reducing the effectiveness of the aerospike, or at the least want to avoid it for complexity sake.

The Gemini capsule, unlike Apollo or Orion, has a pointy nose and a biconic shape, it already has the aerospike "built in" so to speak.

And finally, if you are going to build a tower on top of Orion, why not put the LAS system there? Its a good place for it, since it doesn't interfere with the SM or interstage and a single large motor is more efficient than a bunch of little ones, as well as being considerably safer.

GCNRevenger · 2008-04-17 15:31:23

no, since, despite it's four nozzles, the LAS has a single motor, and this single motor can fail, while, if one of the 6+ motors oif the underside-LAS fails, the Orion may have a sligtly curved trajectory, but the astronauts are saved
but the SM is smaller, so, there is enough space for the underside-LAS
it's only one of dozens possible designs.

No you idiot, if one of those 6+ motors fails, with the extremely high thrust they produce, the imbalance in thrust vector will knock the capsule into an unrecoverable spin. Also, if one of these high-powered rockets explodes, the capsule will surely be destroyed and the crew killed. 6+ has a much higher risk of explosion than 1.

Furthermore, these motors will be heavy; heavier than the single motor on the LAS tower, because they have much more casing than volume due to the cube/square law with their smaller diameter.

And lastly, your idea to use the puny low-thrust attitude control motors on the capsule to control the ~10G LAS separation is nonsense, they don't have anywhere near enough thrust to do the job, and being closer to the capsule and not on the end of the tower also reduces their effectiveness further since they cannot then leverage against the center of mass.

I also reject your casual dismissal that by putting the LAS motors around the rim of the capsule the SM faring must taper to less than the capsules' diameter will cause no problems; the panels will be very close to the solar panels, if they can fit at all.

There are a number of possible designs, but your crazy idea isn't one of them.

gaetanomarano · 2008-04-17 18:12:51

Shuttle doesn't have one because the main tank and not the orbiter is at the tip of the whole vehicle

the shape an dimension of the orbiter have a great influence on aerodynamics and the ET hasn't/can't have a "tower" so, a tower is (maybe) useful but NOT indispensable atop the Orion

...if you are going to build a tower on top of Orion, why not put the LAS system there...

because the "aerodynamic tower" is not absolutely necessary and it's weight is a very small fraction of a LAS

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gaetanomarano · 2008-04-17 18:20:59

...if one of those 6+ motors fails, with the extremely high thrust they produce, the imbalance in thrust vector will knock the capsule into an unrecoverable spin...

"spin" is not so dangerous than a fails of the single rocket... however, my words and your word don't counts about this point since everything must be tested to know how much "spins"

...heavier than the single motor...

the case of REAL solid rockets of every dimensions is just around 10% of the total mass

...low-thrust attitude control motors on the capsule to control the ~10G LAS separation is nonsense...

add LAS thrusters doesn't change so much the mass saving since great part of the LAS wheigt come from its motor and big structure

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Terraformer · 2008-04-18 05:05:47

...if one of those 6+ motors fails, with the extremely high thrust they produce, the imbalance in thrust vector will knock the capsule into an unrecoverable spin...
"spin" is not so dangerous than a fails of the single rocket... however, my words and your word don't counts about this point since everything must be tested to know how much "spins"

So you're saying being in a spacecraft that's spinning crazily around in the air that is shortly going to whack into the ground at high speed is safer than being in one where the engine has just cut out below you so you're waiting for gravity to put its brakes on your speed?

Anyway they could use the re-entry mechanism as an Abort system?

gaetanomarano · 2008-04-18 06:51:44

...spinning crazily around in the air...

depends from the "angle" of spinning, that we can't know before real tests

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RedStreak · 2008-04-18 11:54:31

...spinning crazily around in the air...
depends from the "angle" of spinning, that we can't know before real tests

*stuffs gaetano into a centrifuge that simulates his own design...and watches him puke out his own guts before passing out *

In seriousness, more motors, engines, or thrusters is not always better. If you have an engine that has a 1 in 5 change of failing and 5 in your design...well then 1 out of those 5 will fail...but it can get worse since probability doesn't work that cleanly. More often more engines degrade the payload capacity far far faster than safetey regulations.

NASA isn't going to install some second-hand firework into the LAS - it's going to be something powerful and from a strong rocket firm.

gaetanomarano · 2008-04-18 14:03:09

If you have an engine that has a 1 in 5 change of failing.

the solid motors have not a so low success rate... the SRB had just one failure in 240 SRB launched (and was not its ignition)

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GCNRevenger · 2008-04-18 17:07:19

"spin" is not so dangerous than a fails of the single rocket... however, my words and your word don't counts about this point since everything must be tested to know how much "spins"

Here we go again with the "but you don't KNOW I'm not right" bit.

The LAS motors will generate somewhere around 8-10G of acceleration, so if you have six of them and one fails to fire, then you are going to have 1-2G motor burning on the opposite side with nothing to counter-balance it. And that is a lot of force, which will cause the capsule to enter an end-to-end tumble perpendicular to the axis, dooming the crew.

Or one of the motors could only partially fail, and suffer a burn-through of the nozzle or casing, creating a high "sideways" thrust. This would make the capsule enter a spin around its axis, making parachute deployment impossible much less correctly orienting shield-first for landing. Again, dooming the crew.

Or these very high thrust, very high pressure motors might fail catastrophically, the explosion would tear the shield protection cover apart, shred the corner of the heat shield, penetrate the thin pressure vessel... dooming the crew.

That third item is true of any LAS system, but since the underside-LAS uses six or more motors, it is probably about six times as likely as the single-motor arrangement of the current LAS tower.

GCNRevenger · 2008-04-18 17:13:04

add LAS thrusters doesn't change so much the mass saving since great part of the LAS wheigt come from its motor and big structure

I'm not talking about their mass, the attitude control jets on the Orion capsule simply can't produce enough thrust to guide the capsule if you use any sort of LAS system. You need something that is at least a substantial fraction of the LAS acceleration to be able to orient or correct the trajectory, and puny little tens-of-pounds thrust jets presently called for just can't do it.

How much more are those going to weigh? And where are you going to cram those in on the densely-packed Orion capsule?

gaetanomarano · 2008-04-18 18:58:36

...cause the capsule to enter an end-to-end tumble perpendicular to the axis...

you're right about the "spinning" but "how much" spin may come from a motor failure can be verified only with REAL tests, and, if it's not too much (maybe, in the range of 20-30 degrees) it can be used safely

the other things you say are only exagerations (to denigrate the underside-LAS) that have very low probability to happen

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gaetanomarano · 2008-04-18 19:01:47

...attitude control jets on the Orion capsule simply can't produce enough thrust to guide the capsule...

the attitude control jets are a minimal part of the tower-LAS mass and very small in dimensions, so, it's not a problem to add them to the underside-LAS

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GCNRevenger · 2008-04-18 21:40:47

I think we can assume deadly spinning would occur because of the high thrust required by the LAS motors; they are, after all, designed to push the entire mass of the capsule very fast aren't they? I believe the risk is so significant that we shouldn't even bother testing it.

Oh, and the LAS attitude control thrusters, if those have to rise on the Orion capsule, then even if they were light weight will severely impact the capsules' mass, since they would have to be carried to orbit and back down to the ground.

gaetanomarano · 2008-04-19 03:56:02

I believe the risk is so significant that we shouldn't even bother testing it.

your personal opinion is not enough to be sure that a test is unnecessary

...they would have to be carried to orbit...

no, I've suggested to use the Orion thrusters to save mass, but, if the LAS needs more powerful thrusters, they can be designed to be jettisoned with the LAS

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cIclops · 2008-04-19 06:00:11

Hey guys, please continue this in the topic setup for it.

cIclops · 2008-05-01 03:08:49

From: Evaluation of Separation Mechanism Design (PDF 2MB) - PDF dated 3 Mar 2008

A separation mechanism design is being developed to assure clearance between Orion (Crew Exploration Vehicle and Service Module) and the Spacecraft Adapter (SA) which stays fixed to the Ares upper stage as the two vehicle elements separate from each other during both normal post-launch staging or in an abort event. Figure 1 depicts the Ares/Orion stack configuration prior to separation.

cIclops · 2008-05-13 09:03:59

CEV Parachute Assembly System (CPAS); Variable Porosity. Continuous Ribbon (VPCR)

From Status Report on the Parachute Development (PDF 4MB) - dated 29 Feb 2008

Each Parachute Stage is designed for a single parachute failure
Philosophy is that 1 Drogue Parachute and 2 Main Parachutes are primary landing system
Additional drogue and Main are deployed in parallel to simplify parachute control (no fault detection required)
Drogue Parachutes are initiated at an appropriate altitude and a Mach number less than 0.8
Following Drogue parachute release, Pilot parachutes are mortar deployed and initiate Main parachute deployment

cIclops · 2008-05-16 06:22:23

Program briefing - 15 May 2008 - audio 61 mins

Briefing participants:

- Jeff Hanley, manager, Constellation Program, NASA's Johnson Space Center, Houston
- Mark Geyer, manager, Orion Project, NASA's Johnson Space Center
- Steve Cook, manager, Ares Projects, NASA's Marshall Space Flight Center, Huntsville, Ala.

o Reaching end of the formulation phase
o Lunar capability concept to be reviewed June 2008
o Finishing formulation for Orion and Ares I by summer 2008 and program approval review by end of 2008
o Improved confidence in March 2015 date of Initial Operational Capability for Orion/Ares I
o Excellent prime contractor (ATK, P&W, Lockheed Martin) performance
o KSC preparing for Ares I-X, hardware CDR June 2008
o Internal first flight date is Sep 2013 - unchanged - no impact due to slippage
o Biggest challenge is funding
o Orion PDR slip has no effect on other elements (Ares, ground operations, missions operations, spacesuit)
o Cx budget can manage 6 months of continuing resolution from Congress

Orion
o In preliminary design approaching PDR
o During 22 April checkpoint decided more time needed for integrated vehicle analysis (loads, power, structure)
o PDR now probably in November (slipped two months), another checkpoint in September
o Working to get as much capability, robustness and flexibility
o PDR must show lunar capable vehicle that closes on mass
o LIDS (low impact docking system) testing started on first engineering unit
o First friction stir welds on ground test article expected later this year at MAF
o LAS PAD Abort test now 11 December 2008 (slipped from 23 Sep due to late deliveries of LM electronics)
o No mass margin used to date
o Mass reductions in LAS motor because of reduced drag (reduces load and structure)
o Ascent abort 1 test planned for April 2010
o Landing mode - water nominal, contingency land (requires 200kg in design)
o Investigating cost of water landing (reuse) and changing back to nominal land mode
o Every extra kg in CM costs 9 kg elsewhere!
o TPS will either be PICA or Avcoat- both options are good, to be decided after PDR

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#326 2008-04-16 10:40:28

Re: Orion (CEV / SM) - status

#327 2008-04-16 14:54:57

Re: Orion (CEV / SM) - status

#328 2008-04-16 15:02:44

Re: Orion (CEV / SM) - status

#329 2008-04-16 18:44:03

Re: Orion (CEV / SM) - status

#330 2008-04-16 19:00:30

Re: Orion (CEV / SM) - status

#331 2008-04-17 08:58:52

Re: Orion (CEV / SM) - status

#332 2008-04-17 09:05:55

Re: Orion (CEV / SM) - status

#333 2008-04-17 15:07:31

Re: Orion (CEV / SM) - status

#334 2008-04-17 15:31:23

Re: Orion (CEV / SM) - status

#335 2008-04-17 18:12:51

Re: Orion (CEV / SM) - status

#336 2008-04-17 18:20:59

Re: Orion (CEV / SM) - status

#337 2008-04-18 05:05:47

Re: Orion (CEV / SM) - status

#338 2008-04-18 06:51:44

Re: Orion (CEV / SM) - status

#339 2008-04-18 11:54:31

Re: Orion (CEV / SM) - status

#340 2008-04-18 14:03:09

Re: Orion (CEV / SM) - status

#341 2008-04-18 17:07:19

Re: Orion (CEV / SM) - status

#342 2008-04-18 17:13:04

Re: Orion (CEV / SM) - status

#343 2008-04-18 18:58:36

Re: Orion (CEV / SM) - status

#344 2008-04-18 19:01:47

Re: Orion (CEV / SM) - status

#345 2008-04-18 21:40:47

Re: Orion (CEV / SM) - status

#346 2008-04-19 03:56:02

Re: Orion (CEV / SM) - status

#347 2008-04-19 06:00:11

Re: Orion (CEV / SM) - status

#348 2008-05-01 03:08:49

Re: Orion (CEV / SM) - status

#349 2008-05-13 09:03:59

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