Author Topic: Are we asking too much of Orion?  (Read 16498 times)

Offline renclod

  • Extreme Veteran
  • Full Member
  • ****
  • Posts: 1663
  • EU.Ro
  • Liked: 8
  • Likes Given: 2
Re: Are we asking too much of Orion?
« Reply #20 on: 08/01/2008 06:05 PM »

... are we asking Orion to do too much?

"We" are certainly asking a lot from Orion , but IMO it has nothing to do with the ISS - except maybe filling the gap.

I see Orion pressed between arbitrary (ambitious) requirements :

1/ To fit in a 1.5 launch lunar exploration architecture, where Orion is like 1 part and Altair+EDS like 5 parts. The 5 parts must fit on a reasonably (not arbitrarily) large launcher (Ares V) . More, Orion docks to the ascent module for TLI, so the docking system must be kept as lite as possible - otherwise the AM eats all lunar landed mass capability, with implications on surface stay duration, accessible latitudes, etc. Lite docking systems begs for a lite Orion. Other requirements are related to the heatshield, skip entry, land/sea landing, crew survival and return with a depressurized capsule, etc.

2/ To survive 6 months orbiting the moon. That is because "we" cannot afford to swap the crew every 2 months for example. The larger the target, and the longer the mission duration - the worse are the odds to take a hit from a micro meteoroid, or degrade from radiation. Better shielding equals more mass demands.

3/ To accomodate a crew of 4. Some people say that Orion is just a taxi, Altair being the mission module. But Altair / ascent module is subject to its ows limitations. Taxi cabs don't provide for shower and legs stretching. The first round of design cycle saw Altair's AM with as much room as needed for 4 crew standing upright - no couches.


Offline kraisee

  • Expert
  • Senior Member
  • *****
  • Posts: 10483
  • Liked: 415
  • Likes Given: 19
Re: Are we asking too much of Orion?
« Reply #21 on: 08/01/2008 07:50 PM »
I don't think we are asking 'too much' from Orion.

It has a primary job to do - to carry the crew safely to space, to provide a certain amount of life-support in space and to safely return a crew from either Earth orbital speeds or Lunar return speeds.

That's essentially the same job the Apollo CSM had to do and I don't think anyone considers that 'too much'. Yes, there's a larger contingent of crew and the size is bigger, but we have 40 years worth of additional experience and technology today which they didn't have back then - it shouldn't be that big a deal.

The place where we are 'demanding' a bit too much is in the requirement to cut its weight so drastically in order to fit it on Ares-I.

If you look at the ESAS Report, the 5.5m CEV in there was supposed to mass 23,153kg. The 5.0m Orion is currently planned to mass 20,185kg - although a 500-635kg increase is likely, due to the recent finding that they need to return to a heavier heatshield. Even with that factored in, the CEV will currently mass 20,820kg - that's 89.9% of the original expected mass. I therefore contend any claims of Orion being "overweight" are in error. The project has made choices which have reduced the expected mass quite significantly already.

It is the launch vehicle which is not meeting its original objectives.

In ESAS, LV-13.1, with 4-seg and SSME, was supposed to be able to lift 27.2mT gross payload to insertion. The closest configuration in ESAS to today's Ares-I is LV-16 with a gross payload performance of 28.7mT to insertion.

But today's Ares-I has a gross payload performance of 25.5mT - and that is before any of the negative performance impacts of Thrust Oscillation mitigation are applied. That's already down to 88.9% of its original target performance and TO promises that will go lower still.


So which element is actually not performing correctly? The spacecraft which weighs 10% better than it was originally proposed, of the launcher which is under-performing by 10% and who's technical problems are going to reduce that even further?

Yet watch carefully: It is always Orion who gets the blame. Never the Ares-I.

Ross.
« Last Edit: 08/01/2008 07:54 PM by kraisee »
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline renclod

  • Extreme Veteran
  • Full Member
  • ****
  • Posts: 1663
  • EU.Ro
  • Liked: 8
  • Likes Given: 2
Re: Are we asking too much of Orion?
« Reply #22 on: 08/01/2008 10:20 PM »
Ross - Blame Ares I as much as you want - it ain't gonna solve the weight problem with Orion.

The ESAS report numbers were not proposed like Moses' tables of stone. ESAS was an architecture study and as such it baselined an architecture (1.5) not kilograms nor percentages.

There are limitations to Orion unrelated to the launcher, because even if they would launch Orion with a double capable launcher, Orion must still fit with the rest of the story. Orion cannot be arbitrarily large as long as Ares V is subject to limitations.

Discard Ares I's first stage and replace it with any booster you like. It ain't gonna magically solve the LIDS' tolerance to TLI loads; nor the need for a lite Altair ascent stage.

"essentially the same job the Apollo CSM had to do"

no it's not. Much more demanding job.

IMO.

Offline simcosmos

  • Veteran
  • Full Member
  • ****
  • Posts: 484
  • Portugal
    • SIMCOSMOS
  • Liked: 4
  • Likes Given: 0
Re: Are we asking too much of Orion?
« Reply #23 on: 08/01/2008 10:45 PM »
My opinion:

If making comparisons between ESAS CEV / CLV, etc with today's in-development / being studied vehicles I think that a little of extra data and proper *context* are needed...

Unless I'm incorrect, yes, the ESAS 5.5m diameter lunar CEV had a launch mass of 23153Kg from which:
- 9506 Kg CM
- 4576 Kg SM
- 9071 Kg propellants (Oxigen/Methane) for 66.7KN engine, 363.6s ISP (317s for RCS)


But... The value of ~20.2 (+/-requirement?) to ~21t (+/- current estimation?) for today's CEV is the launch mass for ISS or its *on-orbit TLI* mass and for:
- CM with a smaller 5m diameter (and several other differences from ESAS) but... with a mass (with margins) that might be a bit too close to ESAS bigger CM estimation... I sometimes wonder about what would be the updated estimation for the 5.5m diameter CEV mass, if it was still the current design baseline!
- SM now powered by less efficient hypergolics (~324s ISP or so for main engine)


In the same way, and focusing only in comparing ESAS CLV concepts - powered by a solid booster - with today's AresI, there are some key differences, this beyond the obvious TO issues vs mitigation efforts (unless I'm incorrect, do not remember reading much about it in ESAS), etc... Only as a minor example, ESAS estimated mass for the launch abort system was just ~4.2t (for a 5m diam. CEV, need to check). ALAS is much more massive than that, at least at ~7.3t! ESAS CEV also hadn't those SM covers... To put this in perspective, nowadays estimations for ALAS + SM covers joint mass is about the double of ESAS abort system (this is more than a Soyuz mass), a mass that AresI (or any other CLV for the current CEV design) has to carry until some seconds after good upper stage ignition.

ESAS seems to have been optimistic (and, some other specific times, also pessimistic) in several ways, I mean, when comparing with the reality of more careful (in lack of better word, I mean, more specific) studies / work / research / 'hands on the metal' from which we have current updated estimations (which, in specific cases, still have a margin of unknowns that might be uncomfortable given the potential nature / impact in several Constellation vehicles vs mission requirements vs economics vs other factors).


Ended as started: it is ok to make comparisons with ESAS but... I really think that more care should be taken when doing it. Just my friendly and humble opinion.

António
« Last Edit: 08/01/2008 11:07 PM by simcosmos »
my pics @ flickr

Offline Spacely

  • Veteran
  • Full Member
  • ***
  • Posts: 300
  • Liked: 1
  • Likes Given: 0
Re: Are we asking too much of Orion?
« Reply #24 on: 08/01/2008 11:25 PM »
Ross, can you provide a couple examples of what big-items were lost in the ZBV review?  And then perhaps a rough percentage of how much lost functionality they'll be able to buy back with an Ares I as currently configured  (50%?  80%?)

As far as I've read, the ship still has an airlock, toilet, plenty of storage lockers, 4/6 crew size, smaller-but-more-powerful SM, and solar panels. Are those not the things that make Orion the evolutionary leap over Apollo that was generally desired? 

Offline Free2Think

  • Member
  • Posts: 35
  • Liked: 0
  • Likes Given: 0
Re: Are we asking too much of Orion?
« Reply #25 on: 08/02/2008 12:38 AM »
A reason to look back to ESAS is the Orion/Ares I & V architecture came out of this exercise.  As many have pointed out the current Ares and Orion vehicles don't have much at all in common with ESAS.  If the results in ESAS were so wrong that NASA has had to go through fundamental changes how can anyone claim that the architecture choice resulting from ESAS was correct?

It is absolutely time for a thorough, independent, non-NASA review of the entire program.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32422
  • Cape Canaveral Spaceport
  • Liked: 11162
  • Likes Given: 331
Re: Are we asking too much of Orion?
« Reply #26 on: 08/02/2008 02:55 AM »
As far as I've read, the ship still has an airlock, toilet, plenty of storage lockers, 4/6 crew size, smaller-but-more-powerful SM, and solar panels. Are those not the things that make Orion the evolutionary leap over Apollo that was generally desired? 

Orion never had an airlock and Apollo had a toilet.

Offline Patchouli

  • Senior Member
  • *****
  • Posts: 4398
  • Liked: 181
  • Likes Given: 350
Re: Are we asking too much of Orion?
« Reply #27 on: 08/02/2008 04:37 AM »
As far as I've read, the ship still has an airlock, toilet, plenty of storage lockers, 4/6 crew size, smaller-but-more-powerful SM, and solar panels. Are those not the things that make Orion the evolutionary leap over Apollo that was generally desired? 

Orion never had an airlock and Apollo had a toilet.

Apollo did not fly with a toilet this was deleted for mass or time constraints.

What it flew with was a pretty horrid kludge as for as bathroom facilities go.
It was a bag that an astronaut had to stick to their bottom and then knead chemicals in when they were done.

Apollo did have a simple urinal but I wouldn't call that a toilet either.

Skylab was the first US spacecraft to posses a working space toilet.

Early space travelers had to be mentally really tough.

« Last Edit: 08/02/2008 05:04 AM by Patchouli »

Offline Patchouli

  • Senior Member
  • *****
  • Posts: 4398
  • Liked: 181
  • Likes Given: 350
Re: Are we asking too much of Orion?
« Reply #28 on: 08/02/2008 05:08 AM »
Are we asking too much of the CEV no it just doesn't have a launch vehicle that is up to the job.
I think Orion really needs an LV with a 25 to 40 Ton payload if the two module Apollo design is to be kept.

I think a lot of mass can be saved by either using a three module design or different shape with a better mass to volume ratio but they're not going to change the size,number of modules or shape at this point.

The RS68a Delta IV-H,F9-H, and Direct Jupiter 120 all would be better options for the CLV.

Orion doesn't have an airlock the LM lifting CEV concept did though.
This will make some missions difficult though the J120 can lift enough those missions can just have an an orbital module with an airlock sent up with the Orion.

I did see on NASATV it does have a real bathroom complete with a stall well at least the artwork and mockup they showed did.

It actually looked a little more user friendly then the shuttle's toilet in that it had simpler controls and a larger opening.

If you ask me the Orion seemed to have been based a lot off the Andrew's space CEV.

I think the LM CEV would have been a better choice since it even had redundant TPS plus it road an EELV.



Offline Patchouli

  • Senior Member
  • *****
  • Posts: 4398
  • Liked: 181
  • Likes Given: 350
Re: Are we asking too much of Orion?
« Reply #29 on: 08/02/2008 05:20 AM »
If one assumes that Orion will fly on a liquid rocket the escape system also be simplified as you no longer are running away from a lit SRB.

Bad assumption.  The LAS is sized for an upperstage explosion on the ground

When was the last time a US upper or core stage exploded on the pad?
I think thats fairly rare maybe rare enough it can be disregarded.
I'm talking an explosion vs a fire, trajectory excursion, and even rapid conflagration as with Challenger.
The Shuttle ET,Delta CBC,and SIVB all have no history of exploding on the pad.
Even the SRB has no failure history after returning to flight in 1988.
I'd worry more about something going wrong on the way to the moon as in Apollo 13, the navigational system malfunctioning or the SM not separating during reentry,  then the upper stage or core stage exploding.
« Last Edit: 08/02/2008 05:28 AM by Patchouli »

Offline Patchouli

  • Senior Member
  • *****
  • Posts: 4398
  • Liked: 181
  • Likes Given: 350
Re: Are we asking too much of Orion?
« Reply #30 on: 08/02/2008 05:39 AM »
Ross - Blame Ares I as much as you want - it ain't gonna solve the weight problem with Orion.

The ESAS report numbers were not proposed like Moses' tables of stone. ESAS was an architecture study and as such it baselined an architecture (1.5) not kilograms nor percentages.

There are limitations to Orion unrelated to the launcher, because even if they would launch Orion with a double capable launcher, Orion must still fit with the rest of the story. Orion cannot be arbitrarily large as long as Ares V is subject to limitations.

Discard Ares I's first stage and replace it with any booster you like. It ain't gonna magically solve the LIDS' tolerance to TLI loads; nor the need for a lite Altair ascent stage.

"essentially the same job the Apollo CSM had to do"

no it's not. Much more demanding job.

IMO.


What about flying APAS-89 instead of LIDS if they switch to Jupiter and a two launch scenario and get rid of that awful 1.5 launch scenario the mass issue becomes moot.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32422
  • Cape Canaveral Spaceport
  • Liked: 11162
  • Likes Given: 331
Re: Are we asking too much of Orion?
« Reply #31 on: 08/02/2008 02:01 PM »
If one assumes that Orion will fly on a liquid rocket the escape system also be simplified as you no longer are running away from a lit SRB.

Bad assumption.  The LAS is sized for an upperstage explosion on the ground

When was the last time a US upper or core stage exploded on the pad?
I think thats fairly rare maybe rare enough it can be disregarded.


You can't make that call. Again, troll, you don't have the expertise or knowledge to even suggest.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32422
  • Cape Canaveral Spaceport
  • Liked: 11162
  • Likes Given: 331
Re: Are we asking too much of Orion?
« Reply #32 on: 08/02/2008 02:09 PM »

What about flying APAS-89 instead of LIDS if they switch to Jupiter and a two launch scenario and get rid of that awful 1.5 launch scenario the mass issue becomes moot.


Again, wrong.  It is a Russian system and therefore off the table

Online Svetoslav

  • Veteran
  • Full Member
  • ****
  • Posts: 1222
  • Bulgaria
  • Liked: 533
  • Likes Given: 70
Re: Are we asking too much of Orion?
« Reply #33 on: 08/02/2008 04:23 PM »
Jim: Yeah, I was talking about the problems of Ares... You got me right. The design of Ares, however, affects the design of Orion. I think we should just calm down and wait at least until the test flights before we come up with any conclusions.

Offline Norm Hartnett

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 2306
  • Liked: 56
  • Likes Given: 2
Re: Are we asking too much of Orion?
« Reply #34 on: 08/09/2008 11:52 PM »
From another web site;

"NASA has the man-rating requirements of NPR 8705.2 to exclude EELV's as a viable option (in their opinion) during the ESAS. But now the Ares I crowd has requested and gotten a rewrite of that all-important document to DOWNRATE the human rating requirements. Rev A of the document required two-fault tolerance as a minimum, but Rev B (just released in May) now requires only single-fault tolerance as a minimum."

Any comments?

“You can’t take a traditional approach and expect anything but the traditional results, which has been broken budgets and not fielding any flight hardware.” Mike Gold - Apollo, STS, CxP; those that don't learn from history are condemned to repeat it: SLS.

Offline Danny Dot

  • Rocket Scientist, NOT Retired
  • Senior Member
  • *****
  • Posts: 2794
  • Houston, Texas
  • Liked: 15
  • Likes Given: 1
Re: Are we asking too much of Orion?
« Reply #35 on: 08/10/2008 02:30 AM »
From another web site;

"NASA has the man-rating requirements of NPR 8705.2 to exclude EELV's as a viable option (in their opinion) during the ESAS. But now the Ares I crowd has requested and gotten a rewrite of that all-important document to DOWNRATE the human rating requirements. Rev A of the document required two-fault tolerance as a minimum, but Rev B (just released in May) now requires only single-fault tolerance as a minimum."

Any comments?



The shuttle is two fault tolerance without an escape.  I fought for single fault tolerance plus excape, but was shot down.  Largely because I think the writers of 8705.2 wanted to exclude EELV.  They wanted a NASA developed booster.

Danny
Danny Deger

Offline Norm Hartnett

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 2306
  • Liked: 56
  • Likes Given: 2
Re: Are we asking too much of Orion?
« Reply #36 on: 08/18/2008 07:07 PM »
Well it seems as though Ares I is moving to the right rather briskly. If NASA holds fast to the plan to abandon the ISS in 2016 is it even necessary to retain the six-man capability for Orion? Will dropping that requirement relieve any schedule/weight requirements?
“You can’t take a traditional approach and expect anything but the traditional results, which has been broken budgets and not fielding any flight hardware.” Mike Gold - Apollo, STS, CxP; those that don't learn from history are condemned to repeat it: SLS.

Offline khallow

  • Extreme Veteran
  • Full Member
  • ****
  • Posts: 1956
  • Liked: 6
  • Likes Given: 4
Re: Are we asking too much of Orion?
« Reply #37 on: 08/18/2008 07:57 PM »
Well it seems as though Ares I is moving to the right rather briskly. If NASA holds fast to the plan to abandon the ISS in 2016 is it even necessary to retain the six-man capability for Orion? Will dropping that requirement relieve any schedule/weight requirements?

No idea. But NASA isn't holding fast to any plan to drop the ISS. As far as I can tell, NASA ran a few years ago some budget projections based on the assumption that the ISS is abandoned in 2016. But I wouldn't call that a plan since they aren't doing anything now that would change if they decided one way or the other.
Karl Hallowell

Offline jeff.findley

  • Member
  • Full Member
  • **
  • Posts: 288
  • Liked: 8
  • Likes Given: 1
Re: Are we asking too much of Orion?
« Reply #38 on: 08/19/2008 02:02 PM »
From another web site;

"NASA has the man-rating requirements of NPR 8705.2 to exclude EELV's as a viable option (in their opinion) during the ESAS. But now the Ares I crowd has requested and gotten a rewrite of that all-important document to DOWNRATE the human rating requirements. Rev A of the document required two-fault tolerance as a minimum, but Rev B (just released in May) now requires only single-fault tolerance as a minimum."

Any comments?



The term "man rated launch vehicle" means whatever NASA wants it to mean.  It should come as no surprise to anyone that man rating was used as part of the bait and switch that is Ares I.

Offline Norm Hartnett

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 2306
  • Liked: 56
  • Likes Given: 2
Re: Are we asking too much of Orion?
« Reply #39 on: 08/21/2008 04:43 PM »
Well it seems as though Ares I is moving to the right rather briskly. If NASA holds fast to the plan to abandon the ISS in 2016 is it even necessary to retain the six-man capability for Orion? Will dropping that requirement relieve any schedule/weight requirements?

No idea. But NASA isn't holding fast to any plan to drop the ISS. As far as I can tell, NASA ran a few years ago some budget projections based on the assumption that the ISS is abandoned in 2016. But I wouldn't call that a plan since they aren't doing anything now that would change if they decided one way or the other.

Unless I missed something NASA is still planning on transferring the annual ~$2b ISS funding to the Constellation program post 2016.
“You can’t take a traditional approach and expect anything but the traditional results, which has been broken budgets and not fielding any flight hardware.” Mike Gold - Apollo, STS, CxP; those that don't learn from history are condemned to repeat it: SLS.

Tags: