Could Columbia have been Saved?

Henry Spencer wrote:
In article ,
MSu1049321 wrote:
The STS has no remote-landing capability (unlike the Soviet Buran).

But it does certainly have an autopilot, capable of flying the entire approach
to wheels down. I'm sure I read somewhere that that had in fact been tested.

Never in orbital flight. The engineers would like to see it done, but the
pilots don't like the idea, and so far the pilots have prevailed.
snip
(There is nothing fundamental about any of this -- modifying the shuttle
to do an unmanned return would not be terribly hard -- but it's not
something that could be improvised in orbit.)

Scavenge a relay or two from somewhere, find a panel light the ground can
light up, pull the switch, and hook the relay up.
Problem solved?

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http://inquisitor.i.am/ | | Ian Stirling.
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In article ,
Ian Stirling wrote:
(There is nothing fundamental about any of this -- modifying the shuttle
to do an unmanned return would not be terribly hard -- but it's not
something that could be improvised in orbit.)

Scavenge a relay or two from somewhere, find a panel light the ground can
light up, pull the switch, and hook the relay up.
Problem solved?

You'd need more than one or two relays, and the computers don't have handy
panel lights attached as far as I know. It might be marginally feasible
but it would not be a small or easy job.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

Now wait a sec, I think I read somewhere that while gear deployment is done by
a manual switch, there IS a tie-in to the computer or to a radar altimeter such
that in the last critical seconds, a pyro will BLOW the doors open and the gear
down and locked, if the regular system fails. That could be modified, I'm
sure, some time in the next year.

(MSu1049321) wrote in
:

Now wait a sec, I think I read somewhere that while gear deployment is
done by a manual switch, there IS a tie-in to the computer or to a
radar altimeter such that in the last critical seconds, a pyro will
BLOW the doors open and the gear down and locked, if the regular
system fails.

You may well have read it somewhere, but this is what NASA says about how
the system works - no links to computers or altimeters, just a simple time-
activated backup to the crew pressing the button:

http://spaceflight.nasa.gov/shuttle/.../lgear/overvie
w.html

For deployment of the landing gear, the uplock hook for each gear is
activated by the flight crew initiating a gear-down command. The uplock
hook is hydraulically unlocked by hydraulic system 1 pressure applied to
release it from the roller on the strut to allow the gear, assisted by
springs and hydraulic actuators, to rotate down and aft. Mechanical linkage
released by each gear actuates the respective doors to the open position.
The landing gear reach the full-down and extended position within 10
seconds and are locked in the down position by spring-loaded downlock
bungees. If hydraulic system 1 pressure is not available to release the
uplock hook, a pyrotechnic initiator at each landing gear uplock hook
automatically releases the uplock hook on each gear one second after the
flight crew has commanded gear down.
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In article ,
MSu1049321 wrote:
Now wait a sec, I think I read somewhere that while gear deployment is done by
a manual switch, there IS a tie-in to the computer or to a radar altimeter such
that in the last critical seconds, a pyro will BLOW the doors open and the gear
down and locked, if the regular system fails.

Nope, you've misunderstood. The pyro backup system is also tied to the
manual switch; it is a backup for the primary deployment hardware, not a
backup for the switch.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

On Wed, 2 Jul 2003 04:03:17 GMT, in a place far, far away,
(Henry Spencer) made the phosphor on my monitor
glow in such a way as to indicate that:

MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

Congratulations to you and the entire team that made this happen,
Henry.

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"Henry Spencer" wrote:
In article ,
Rand Simberg wrote:
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |


Congratulations to you and the entire team that made this happen,
Henry.

Thank! The guys at Dynacon and UTIAS-SFL deserve most of the credit; my
involvement was limited. But I'm very happy to see it launched and
healthy, not least because I'm rather more deeply involved in a couple of
follow-on projects, which will be a lot easier to fund if MOST is a
conspicuous success.

Well I certainly hope it will be. And judging by its
design and purpose, it certainly stands an excellent
chance of doing so. Good luck, and congratulations on
the progress you've already made so far.

"Henry Spencer" wrote in message

Thank! The guys at Dynacon and UTIAS-SFL deserve most of the credit; my
involvement was limited. But I'm very happy to see it launched and
healthy, not least because I'm rather more deeply involved in a couple of
follow-on projects, which will be a lot easier to fund if MOST is a

Who is "UTIAS-SFL"?

"Michael R. Grabois ... change $ to \"s\"" wrote:

On 02 Jul 2003 00:39:06 GMT, (MSu1049321) wrote:

Now wait a sec, I think I read somewhere that while gear deployment is done by
a manual switch, there IS a tie-in to the computer or to a radar altimeter such
that in the last critical seconds, a pyro will BLOW the doors open and the gear
down and locked, if the regular system fails. That could be modified, I'm
sure, some time in the next year.

And to add to what Jorge and Henry have said, there are some things you have
mixed up....

Basically, the gear deploy system works like this:

1. At 2000 ft altitude, the PLT presses the Landing Gear Arm button. The CDR
can do this too, since he's got an identical button on the left side, but he's
busy flying. When pressed, a series of relays close, some of which cause
capacitors in the pyrotechincs to charge up.

2. At 300 ft altitude, the PLT presses the Landing Gear Down button. This
closes several other relays, some of which cause a hydraulic actuator to move.
This actuator looks somewhat like a letter "C" facing downwards, and as the
"arms" of the actuator open, the landing gear is released. The gear doors and
the gear itself are mechanically linked, so that as the gear drops, the door
opens. You cannot have the case where the gear drops and the door does not
open.

3. One second after the Down button is pushed, a proximity sensor detects
whether the gear is still in place. If it is, then the sensor sends a signal to
the pyros to fire. This all takes place "behind the scenes", as only MCC can
tell if the gear is dropped hyraulically or via pyros.

The current system does have a tie-in to the GPC, however. In the Heads-Up
Display (HUD) is a reminder to the crew about the status of the gear so that
they don't have to look at the talkbacks next to the pushbuttons. At a
predetermined altitude (set by I-load), a check of the status is made, and if
the GPC thinks the gear is still up, it will flash a reminder (I think it's
"//ARM"). The gear in transit registers on the HUD as something like "//GR/",
and gear down is shown as something like "GR-DN". It's just a status on the
display, though. You can't just add a relay somewhere to make the GPC deploy
the gear, it's more complicated than that.

Do you know where I could get wiring diagrams? Being a Boeing employee,
I could probably access them online if I knew where to look.

That is my old alma mater. I did not know that they had a space flight lab
so I did not recognize the acronym.

"Henry Spencer" wrote in message
...
In article ,
steve podleski wrote:
Thank! The guys at Dynacon and UTIAS-SFL deserve most of the credit;
my
involvement was limited...

Who is "UTIAS-SFL"?

UTIAS is University of Toronto Institute for Aerospace Studies. SFL is
the Space Flight Laboratory, a group within UTIAS.

Dynacon (which was itself, long ago, more or less a spinoff from UTIAS)
was prime contractor for MOST, and did overall systems engineering,
attitude control, and (most of) power. SFL did radios, structure,
thermal, main computer, camera electronics, assembly, testing, and odds
and ends. Jaymie Matthews's lab at UBC did the telescope and camera.
There were other minor participants, who I'd mostly have to look up, but
those were the major ones.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |