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Science Forum Index » Space - Shuttle Forum » Orion G-force question...
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| Alan Erskine... |
 Posted: Fri Jun 13, 2008 8:53 am |
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What are the launch and re-entry G-forces for Orion? Surely, a capsule will
be worse than the shuttle. If they have to use a recumbant seat for ISS
crews returning on the shuttle, will that be sufficient for Orion? What
about longer-term crews; how will they fair returning on Orion? |
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| Posted: Fri Jun 13, 2008 8:53 am |
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On Jun 13, 9:53 am, "Alan Erskine" <alan.ersk... at (no spam) bigpond.com> wrote:
Quote: What are the launch and re-entry G-forces for Orion? Surely, a capsule will
be worse than the shuttle. If they have to use a recumbant seat for ISS
crews returning on the shuttle, will that be sufficient for Orion? What
about longer-term crews; how will they fair returning on Orion?
No issue here
The Orion "couches" are recumbent by definition
No different than the Soyuz that have been used for long term station
residents before the shuttle existed and since |
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| Brian Gaff... |
| Posted: Sat Jun 14, 2008 2:33 am |
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Well cannot be worse than Soyuz of late and nobody has died from the g
forces yet!
Brian
--
Brian Gaff - briang1 at (no spam) blueyonder.co.uk
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Alan Erskine" <alan.erskine at (no spam) bigpond.com> wrote in message
news:SZu4k.10582$IK1.5502 at (no spam) news-server.bigpond.net.au...
Quote: What are the launch and re-entry G-forces for Orion? Surely, a capsule
will be worse than the shuttle. If they have to use a recumbant seat for
ISS crews returning on the shuttle, will that be sufficient for Orion?
What about longer-term crews; how will they fair returning on Orion?
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| Posted: Mon Jun 16, 2008 12:26 pm |
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On 14 Giu, 09:33, "Brian Gaff" <bria... at (no spam) blueyonder.co.uk> wrote:
Quote: Well cannot be worse than Soyuz of late and nobody has died from the g
forces yet!
Brian
--
Brian Gaff - bria... at (no spam) blueyonder.co.uk
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!"Alan Erskine" <alan.ersk... at (no spam) bigpond.com> wrote in message
news:SZu4k.10582$IK1.5502 at (no spam) news-server.bigpond.net.au...
What are the launch and re-entry G-forces for Orion? Surely, a capsule
will be worse than the shuttle. If they have to use a recumbant seat for
ISS crews returning on the shuttle, will that be sufficient for Orion?
What about longer-term crews; how will they fair returning on Orion?
I think that more than g-force is important that is possible to abort
the launch at any time. The soyuz design forgive an incredible range
of possible problems. Simple and stupid, but very robust.
They can go out of route of undred of kilometers and still survive.
Or they can survive an incredible mess like this:
http://www.astronautix.com/flights/soyuz181.htm
If it was the shuttle they could have die a dozen of times.
The soviets didn't divulgate what they considered an unsuccesful
launch. But as for me this is the the most succesful example of how a
good design for manned space flight has to be. Simple, robust and
having a low energy abort mode at almost any time of the flight, even
if you do many mistakes. |
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| Posted: Mon Jun 16, 2008 1:48 pm |
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On 17 Giu, 00:33, Brian Thorn <bthor... at (no spam) suddenlink.net> wrote:
Quote: On Mon, 16 Jun 2008 15:26:01 -0700 (PDT), bal... at (no spam) gmail.com wrote:
I think that more than g-force is important that is possible to abort
the launch at any time. The soyuz design forgive an incredible range
of possible problems. Simple and stupid, but very robust.
And yet it has suffered the same number of fatal accidents as the
Space Shuttle.
Brian
Sorry, my english is bad.
I've not data... I know about soyuz 11 accident in 1971 but recently
(say,the last 30 years) I don't remember fatal Soyuz missions.
A complicated thing like STS contains so many points of failure that
it requires an incredible good work to operate it. It contains many
parts, and the failure of just one of them could be fatal. So failure
rate of any single piece and tollerances have to be extremely good.
Probability is on the side of "simple" veichles.
I expect that Orion will be more Soyuz (but also Apollo) like in the
sense that it will be much more simple and robust.
And it will forgive a lot of mistakes. Russians made incredible
mistakes during some missions, but despite this they very often saved
the crew.
A capsule is intrinsecaly more safe. I linked Soyuz 18-1 as an
extreme example, but also Apollo 13 is a story of fantastic
robustness.
A manned launch has to do just one thing: take humans to space and
back in the more simple and safe way. Never mind it's not "sexy".
Cargo and other stuff could be launched in separated launch, as they
are more expendable.
The topic is about g-forces. When Soyuz does a ballistic reentry it
can reach 10 g. I simply expect that Orion could withstand even more
weird reentries than this. Human body can resist a lot of g.
Hopefully it will never be required, but in case better sick than
disintegrated.
This time is better to do it more robust with less frills. |
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| Brian Thorn... |
| Posted: Mon Jun 16, 2008 5:33 pm |
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On Mon, 16 Jun 2008 15:26:01 -0700 (PDT), balpao at (no spam) gmail.com wrote:
Quote: I think that more than g-force is important that is possible to abort
the launch at any time. The soyuz design forgive an incredible range
of possible problems. Simple and stupid, but very robust.
And yet it has suffered the same number of fatal accidents as the
Space Shuttle.
Brian |
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| Greg D. Moore (Strider)... |
| Posted: Mon Jun 16, 2008 8:08 pm |
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<balpao at (no spam) gmail.com> wrote in message
news:a574f617-2ea6-4d6a-8c59-d01db8bb2e1a at (no spam) 34g2000hsh.googlegroups.com...
Quote: On 17 Giu, 00:33, Brian Thorn <bthor... at (no spam) suddenlink.net> wrote:
On Mon, 16 Jun 2008 15:26:01 -0700 (PDT), bal... at (no spam) gmail.com wrote:
I think that more than g-force is important that is possible to abort
the launch at any time. The soyuz design forgive an incredible range
of possible problems. Simple and stupid, but very robust.
And yet it has suffered the same number of fatal accidents as the
Space Shuttle.
Brian
Sorry, my english is bad.
I've not data... I know about soyuz 11 accident in 1971 but recently
(say,the last 30 years) I don't remember fatal Soyuz missions.
Which is a somewhat meaningless statistic.
If I can suggest another metric:
Number of successful flights between fatalities, the Shuttle wins.
Quote:
A complicated thing like STS contains so many points of failure that
it requires an incredible good work to operate it.
So do 747s, and yet they're not falling out of the skies.
Quote: It contains many
parts, and the failure of just one of them could be fatal. So failure
rate of any single piece and tollerances have to be extremely good.
Probability is on the side of "simple" veichles.
No, the failure of ANY single piece is meaningless.
Many of those parts are for redundancy and increase robustness or
capabilities.
And no, you can't just do a parts count and argue "simplicity = robustness".
The interaction between those parts is critical.
Quote:
I expect that Orion will be more Soyuz (but also Apollo) like in the
sense that it will be much more simple and robust.
Consider the failure modes that Soyuz has demostrated recently. They have
been nearly fatal. In the most recent case it looks like things could have
gone the other way VERY easily.
Quote:
And it will forgive a lot of mistakes. Russians made incredible
mistakes during some missions, but despite this they very often saved
the crew.
And killed two.
Quote:
A capsule is intrinsecaly more safe.
I see no evidence to support this. Once you start to get to the level of
complexity of something like the Soyuz, you've lost a lot of the "intrinsic"
factor. Witness the most recent flight.
Quote: I linked Soyuz 18-1 as an
extreme example, but also Apollo 13 is a story of fantastic
robustness.
Not really. In fact it showed some major shortcomings of the design that
they were only able to overcome because they essentially had a second
spacecraft with them and incredible people on the ground. Had the tank
vented after landing, Apollo 13 would have resulted in fatalities.
Quote:
A manned launch has to do just one thing: take humans to space and
back in the more simple and safe way. Never mind it's not "sexy".
It has to do much more than that. It has to support them while they're
there, provide for proximity ops, possibly docking and at the very least
berthing.
Quote:
Cargo and other stuff could be launched in separated launch, as they
are more expendable.
Tell that to the folks who built Hubble. I don't think they'd have thought
it was all that "expendable".
Quote:
The topic is about g-forces.
But you keep trying to change it to other safety factors.
Quote: When Soyuz does a ballistic reentry it
can reach 10 g. I simply expect that Orion could withstand even more
weird reentries than this.
On what basis?
Quote: Human body can resist a lot of g.
Hopefully it will never be required, but in case better sick than
disintegrated.
This time is better to do it more robust with less frills.
So let's replace a fairly well understood but far from perfect system with a
completely new one with completely new failure modes. Good plan. Oh and
while we do that, let's make a lot of the same mistakes we made with the old
system of calling it 'operational' after just a few flights and incorporates
some of the less robust portions of the previous design.
Orion and Ares is a dog.
--
Greg Moore
SQL Server DBA Consulting Remote and Onsite available!
Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html |
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| Brian Thorn... |
| Posted: Mon Jun 16, 2008 8:53 pm |
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On Mon, 16 Jun 2008 16:48:12 -0700 (PDT), balpao at (no spam) gmail.com wrote:
Quote: I think that more than g-force is important that is possible to abort
the launch at any time. The soyuz design forgive an incredible range
of possible problems. Simple and stupid, but very robust.
And yet it has suffered the same number of fatal accidents as the
Space Shuttle.
Sorry, my english is bad.
You are doing very well.
Quote: I've not data... I know about soyuz 11 accident in 1971 but recently
(say,the last 30 years) I don't remember fatal Soyuz missions.
The same could be said of the Space Shuttle at the beginning of 2003,
when Shuttle had flown 87 successful missions and 17 years since the
Challenger accident. But the 88th flight saw the loss of Columbia.
88 flights is about as many as Soyuz has now flown since Soyuz 11.
Quote: A complicated thing like STS contains so many points of failure that
it requires an incredible good work to operate it. It contains many
parts, and the failure of just one of them could be fatal. So failure
rate of any single piece and tollerances have to be extremely good.
Probability is on the side of "simple" veichles.
Yes, the Soyuz should statistically have a much better chance of
survival. The problem is that, here in the Real World, it does not.
Quote: The topic is about g-forces. When Soyuz does a ballistic reentry it
can reach 10 g. I simply expect that Orion could withstand even more
weird reentries than this.
Orion should be somewhat lower g's than Soyuz, by virtue of its shape
(taken from Apollo) generating greater lift, allowing a more gentle
entry profile, at least unless it defaults to a ballistic entry like
recent Soyuz entries.
Brian |
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| OM... |
| Posted: Mon Jun 16, 2008 11:35 pm |
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On Mon, 16 Jun 2008 16:48:12 -0700 (PDT), balpao at (no spam) gmail.com wrote:
Quote: Sorry, my english is bad.
....Compared to Bbo Hallr, you're a native speaker! :-)
OM
--
]=====================================[
] OMBlog - http://www.io.com/~o_m/omworld [
] Let's face it: Sometimes you *need* [
] an obnoxious opinion in your day! [
]=====================================[ |
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| Posted: Wed Jun 18, 2008 1:44 am |
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I' understand (and supposed before you said to me) that Orion will
expose the crew to less g-forces during normal operations.
But, as I said, I expect it will be able to resist to much higher g-
forces in emercency.
Just a little more thermal shielding and design requirement seems
affordable. And it's not a luxury. Many times in the story of
astronautics this capability saved the crew.
Let alone the Russians, but Apollo 13 re-entry has been much faster
than for normal Apollo missions.
I agree they are alive thanks the fantastic work of people at ground,
but a design margin for thermal shielding, capsule stability and
whatever else during re-entry also has been an essential condition.
I suppose they'll take this safety margin or better for Orion, also.
So the question of the topic, IMHO, could have multiple answers:
Orion g-forces for:
- normal re-entry for a certain earth orbit?
- re-entry for a certain hyperbolic trajectory (say,after a trip to
the moon)?
- maximum allowable in case of emergency/ veichle partially out of
control etc.?
I suppose one of the many reasons for the return to the "blunt body
reentry" is that you have not to be scared for any little flaw in a
tile anymore.
If I said wrong the more experts could correct. |
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