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PBS's "Nova" and MER



 
 
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  #11  
Old January 5th 04, 06:08 PM
Pat Flannery
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Default PBS's "Nova" and MER



bob wrote:


Did anyone else find the simulation of the failed landing as disturbing as I
did?


The one where the landing airbags popped? Yes, I cringed at that one.

Pat

  #12  
Old January 5th 04, 06:10 PM
Scott Ferrin
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Default PBS's "Nova" and MER

On Mon, 05 Jan 2004 07:43:54 GMT, Brett Buck
wrote:

Scott Ferrin wrote:


This is also why I fear the day when the "cheap access to
space"/X-Prize types actually try to launch.




I imagine the big companies do too. They'll look pretty stupid if
Rutan succeeds.


Succeeds in winning the X-Prize? Who the hell cares? You guys are
really something.


Maybe you could explain to us why they need the "levelest and flatest
floor in the world" just to line up the friggin' boosters on the Delta
IV. Hell the sections of a drive shaft on a Nimitz class carrier need
to be lined up just as well and they use a CRANE in a shipyard. Then
maybe you could explain why the ATF program was able to produce two
types of fighters (YF-22 and YF-23) both of which had far more new
technology at a FAR cheaper price than this "new technology" little
spaceplane NASA wants to build. The fact of the matter is that NASA
does go way down the diminishing returns curve when comes to
precision, complication, and materials all for CYA and because they're
stuck in this mentality of "we're NASA so it all needs to be gold
plated".




The X-prize is not even on the radar screen to
Lockheed, TRW, or Boeing, and whether or not anyone wins or not, it
won't make a whit of difference to the majority of the industry. It
could have been done in 1960 if anyone had cared to, and you took out
the "no government money" clause. Nobody wanted to, because then as now,
it doesn't really lead anywhere or advance the state of the art in any
way. Far more capable plans were well on their way to succeeding in that
era, but were derailed, once again based on "lack of need" that persists
to this day.



If there is a lack of need then why the X-34, 37, 38, and 40? Why the
tiny spaceplane NASA wants to build? The X-20 didn't get cancelled
because of no need, it was cancelled because of $$$$$.





Rutan has a backer with money, I applaud him for taking on the task,
and I expect that eventually he will make the X-prize requirements
(before or after the deadline). Coefficient of relevence to space
technology is negligible.


A newly designed launch vehicle and manned rocket for far cheaper than
a "lifeboat" that all it needs to do is glide back to earth?
Something of which they've already been doing for DECADES?. First
manned use of hybrid rockets? Totally new way of reducing speed when
returning to earth? Yep, you're right, no relevence whatsoever.





I will grant that it will make sci.space.policy "true beleivers"
ecstatic, but that's really not much of a goal.

Brett


Spoken like a true believer in unnecessary complexity, precision, and
gold plating.
  #13  
Old January 5th 04, 06:16 PM
Henry Spencer
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Default PBS's "Nova" and MER

In article ,
Pat Flannery wrote:
This to me STRONGLY suggest that such probes need more time and funding
thrown at them in the future; if even for a few million dollars and a
extra month or so leading up to launch; looking at this, one can
certainly see a distinct downside to BFC in that these were all serious
problems that were being addressed at the last moment via lots of hard
work, sleepless nights, and just plain dumb luck.


Are you under the impression that such things never happened on the old
slower/costlier/worse projects? If so, you are sadly mistaken.

It's easy to say that a bit more money and time would fix these things,
but in practice, that's not what the money and time get used for -- they
get used to make the mission more ambitious instead.

The most telling argument against "more money would make these problems
go away" is that we have plenty of evidence that *it doesn't*.

I will not even comment on the idea to launch the probes before their
landing software was completed; and then uploading it to them in-flight...


There's nothing particularly wrong with that, if you think of software
uploads as routine practice rather than as a dire emergency measure.

or the extremely young average age (by engineering standards) of the
people involved in the MER program as shown in the special, after Dan
Goldin's scythe cut down all the old pros at NASA.


Most of the old pros have hit retirement age anyway. The problem goes
back much farther than Goldin -- it's a consequence of post-Apollo
contraction and the accompanying hiring freezes.

And actually, young is good. An unfortunately large fraction of the
middle-aged people at JPL, and NASA in general, are viewgraph engineers
whose net contribution to a fast-paced results-oriented project would be
negative. (If memory serves, the people picking the Mars Pathfinder team
carefully excluded them.)
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |
  #14  
Old January 5th 04, 07:31 PM
Jonathan Silverlight
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Default PBS's "Nova" and MER

In message , Pat Flannery
writes
Our local PBS station ran a special tonight on the MER spacecraft and
their rovers design, testing, and launch (as well as the successful
landing of #1)
The show was chock-full of info on the rovers and what they can
do;Which if they work right is very impressive- but in my opinion
showed a major flaw in the program timeline that led up to their
launch...in the last few months before the launch, the MER team runs
into no less than _5_ unexpected problems, any one of which is a
complete show-stopper if not fixed:
1.) An attempt to use a Pathfinder type parachute for the descent of
the rovers fails after a helicopter drop, as it is not structurally
strong enough to take the extra weight of the MER probes.
2.) A redesigned chute fails to open properly in wind tunnel tests. Its
central hole is too large and this makes it "squid" as it attempts to
open, due to too much airflow out of the top. The test that fixes this
flaw is done by sewing in a constraint around the top hole; and holding
the chute reefed via two guys in the wind tunnel with a cord at the
apex of its shroud lines; as there is neither time nor money to do
another test ejection from its canister. The chute is found to have
been built to the wrong specifications, and a redesigned one has to be
made in short order to correct the flaw.
3.) One of the landing airbags ruptures during a bounce test. Again
unexpected...again fixed with a few months to go.


Beagle 2 had the same set of problems, but sadly it doesn't seem to have
survived them.

I will not even comment on the idea to launch the probes before their
landing software was completed; and then uploading it to them
in-flight-


There's a precedent for that. One of your probes (NEAR ??) was being
tested for millennium compliance in mid-flight.
--
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  #15  
Old January 5th 04, 09:12 PM
Bill Higgins
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Default PBS's "Nova" and MER

On Mon, 5 Jan 2004, Pat Flannery wrote:

Our local PBS station ran a special tonight on the MER spacecraft and
their rovers design, testing, and launch (as well as the successful
landing of #1)


I missed this, alas, but a check of the pbs.org site showed that my local
station is repeating it on Tuesday the 6th, and twice again next Sunday.

If you missed it too, and you are within reach of a U.S. PBS station, poke
around the site and ask it when *Nova* episodes are shown in your town.

--
Bill Higgins | They can have my World Almanac
Fermilab | when they pry it from my cold, dead fingers.
Internet: | Or when next year's edition comes out, whichever is first.
| --Lois A. Fundis
  #16  
Old January 5th 04, 10:32 PM
Dave Michelson
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Default PBS's "Nova" and MER

Bill Higgins wrote:

Our local PBS station ran a special tonight on the MER spacecraft and
their rovers design, testing, and launch (as well as the successful
landing of #1)


I missed this, alas, but a check of the pbs.org site showed that my local
station is repeating it on Tuesday the 6th, and twice again next Sunday.

If you missed it too, and you are within reach of a U.S. PBS station, poke
around the site and ask it when *Nova* episodes are shown in your town.


Beter yet, follow this link:

http://www.pbs.org/wgbh/nova/schedule-local.html

--
Dave Michelson


  #17  
Old January 6th 04, 01:37 AM
bob
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Default PBS's "Nova" and MER

i think we have to cut some slack to the developement for the hasty work
created by the astonomy (once every 26 month mars/earch minimum approach).
It was not a case of FBC, just a deadline that was impossible to work
around.

I was not worried about the youth of the crew: it was unavoidable given the
all at once surge of the 60's (it takes several generations of more even
funding that NASA has ever had to even things out, and organizational
cultural transmission of experience is the best we could hope for. Given the
level of change in technology, this is probably not as important as we
think.

Finally, i worried not at all about loading software after the hardware went
up. Software is just that, soft. They had the device here, software can be
tested. If the hardware is designed correctly, software follows the form. I
design software for a living, and I know who's boss: reality, not me.

bob


  #18  
Old January 6th 04, 03:03 AM
Derek Lyons
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Default PBS's "Nova" and MER

Scott Ferrin wrote:

Maybe you could explain to us why they need the "levelest and flatest
floor in the world" just to line up the friggin' boosters on the Delta
IV. Hell the sections of a drive shaft on a Nimitz class carrier need
to be lined up just as well and they use a CRANE in a shipyard.


Well, you are utterly and completely *wrong*.

The crane is used to install the segments into the hull. Once in the
hull all of the bearings have adjustments to align and center the
drive shaft, and lasers and micrometers are used to ensure that the
alignment is spot-on perfect.

D.
--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.
  #19  
Old January 6th 04, 03:25 AM
Pat Flannery
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Default PBS's "Nova" and MER



Henry Spencer wrote:

Are you under the impression that such things never happened on the old
slower/costlier/worse projects? If so, you are sadly mistaken.

I was concerned about the compressed timeline that was being used; when
you are within six months of launch, and your parachute system hasn't
been successfully tested yet, things seem too rushed.


It's easy to say that a bit more money and time would fix these things,
but in practice, that's not what the money and time get used for -- they
get used to make the mission more ambitious instead.

As I stated in the original posting, they had five "iffy" things to fix
(six if you count the IR scanner with no existing spares that they
shock-tested); any one of these things doesn't get fixed on time, and
you have to push the launch back to the next Earth-Mars launch window a
couple of years down the road. Even a few extra weeks would have
helped. And you can do as ambitious of mission as you want, but the
primary key to it is that the ambition be balanced against it's odds of
success, otherwise all you've accomplished is flushing a lot of time and
money down the toilet, MPL and Beagle style.


The most telling argument against "more money would make these problems
go away" is that we have plenty of evidence that *it doesn't*.


Pioneer 10 & 11 had time and money on their sides; both worked great.
Viking 1 & 2 had lots of money and time; both worked great; both the
orbiters...and landers.
Voyager 1 & 2 had lots of money and time; both worked great.
The only big-budget long-span program semi-flop we have had was Galileo;
and its problems were as much due to a hurried redesign of its launch
method and trajectory as anything else, and it still got a lot of its
job done at Jupiter.
In comparison to this, our lower-cost fast timeline missions are running
around 50% as to success rate.





I will not even comment on the idea to launch the probes before their
landing software was completed; and then uploading it to them in-flight...



There's nothing particularly wrong with that, if you think of software
uploads as routine practice rather than as a dire emergency measure.


What happens if you launch them, and then run into some
software-spacecraft compatibility problem that can't be fixed before the
time that the software is needed, due to a compatibility problem that
can't be fixed in-flight; but could have been found via ground testing
of the systems and software on the ground prior to launch? If that had
happened on the two MER flights they would have had no way to get them
ready for landing.



or the extremely young average age (by engineering standards) of the
people involved in the MER program as shown in the special, after Dan
Goldin's scythe cut down all the old pros at NASA.



Most of the old pros have hit retirement age anyway. The problem goes
back much farther than Goldin -- it's a consequence of post-Apollo
contraction and the accompanying hiring freezes.

And actually, young is good. An unfortunately large fraction of the
middle-aged people at JPL, and NASA in general, are viewgraph engineers
whose net contribution to a fast-paced results-oriented project would be
negative. (If memory serves, the people picking the Mars Pathfinder team
carefully excluded them.)


But some of the old guys might have pointed out that you may want to put
a method on the outside of one or more of the three MER lander petals
that would let you get the rover out if you needed to work on it without
firing the pyros; that wasn't well thought out. This team has now
learned that lesson; how many more do they need to learn?

Pat

  #20  
Old January 6th 04, 03:42 AM
Pat Flannery
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Default PBS's "Nova" and MER



Bill Higgins wrote:

On Mon, 5 Jan 2004, Pat Flannery wrote:

I missed this, alas, but a check of the pbs.org site showed that my local
station is repeating it on Tuesday the 6th, and twice again next Sunday.


At least the Tuesday one will have the latest images from the lander...
it's a very interesting show; one thing they go into is just what a
small area of Mars MER can operate in due to the need for sufficiently
thick atmosphere to slow the probe's parachute sufficiently, and the
need to have the sun almost overhead for the solar panels. It's only a
thin band around the equator, minus any highlands.

Pat

 




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