> What made the man-safety issues of PCSAT2 costly?
> Didn't you just agree to power PCSAT2 off for long
> periods of time whenever the need arose?
I'll answer this on the AMSAT-BB to share the pain.
This should be a real eye-opener as to what the space business
is like from the inside out...
A 2W TX on shuttle or ISS is considered a catastrophic safety
hazard due to potential for loss of life due to interference or
reset of the space suit, or shuttle ISS control systems or
anything else.
Not only must we then design a system with FOUR independent
ground commandable OFF switches in series (or three that have
positive feedback) they all must be proven to be man safe to
NASA man safe criteria. This means, not a $2 on/off switch, but
a $5,000 on/off switch that has been built from raw materials
that have a paper work history all the way back to the
manufacturer certifying the materials, assembly procedures, and
all testing, and all handling of -each- such switch. Now that
is just a switch. You have to have this for every component
involved in the on/off of a man-safe circuit or that an
astronaut touches.
Then you have to present this material and plans 4 times to the
30 or so engineers on the NASA Safety Review board. Each
meeting involves flying people from all over the country to
participate. Meetings usually take 2 days to review every
detail of the design. At $200 per man day plus travel, that is
$6000 times 4 or $24,000 just for the meetings, not counting the
days of preps and reviews of everyone leading up to it.
Then the documentation, and reviews, and presentations... And
testing, and travel to observe testing, and paper work over 3
years, all because a 2W TX is considered to be a catastrophic
hazard. Then you fly.
Now you say, we "simply agree to turn it off". But this
involves a week of planning for each "turn off". NASA must have
a plan at least a week in advance, not only showing when we are
going to turn it off, but what backup systems we have in place
to assure that it will be off. And the exact time is planned,
but is not known for sure, It changes up to the day of the EVA
or whatever evolution. Hence we are constantly revising this
plan all week long...
We have to coordinate the schedules of all our ground stations,
find who can be awake at the right time, and still have 2 more
chances to turn it off after that. Each change of 5 minutes to
the evolution completely changes the ground station we need and
all our planning. Mean time, NASA has to man the consoles, and
DOD has to provide a 24 hour operator at their console to talk
to NASA to talk to me. Then we send the commands, and have to
report it to all concerned.
Meanwhile NASA has to plan contingencies in case we fail to get
the switch turned off from the ground. They have to include the
plan in their Astronauts procedures to take time out of their
EVA preparations (getting their suits ready) to include then
going over to the HAM radio and going through 74 steps in a 5
page procedure to send the OFF command themselves. Yes, 74
steps... Just to send the DTMF code 123456, because you have to
have a procedure for the crew to turn on the radio, set the
channels, tune the radio, set the controls, verify operation,
etc, etc... This requires 15 minutes or more and has to be done
before they get into their space suits. Which takes 3 hours.
So, this means we had to have exhausted all three of our ground
opportunities prior to that 3 hours, so, we have to attempt to
send the command 6 hours prior to EVA.
Many times that is in the middle of the night over the ground
station of choice, and since we had to do this for every EVA,
every Docking, and Every use of the robot arm, you can see why
no-one is going to let us do that again. It wore everyone out.
DOD had at least 6 people probably 1/4 time on this project over
3 years, that is about $500,000. And that had nothing to do
with actually building the hardware. That is just "oversight
and management" overhead. Presumably if we didn't have all the
man-safety issues due to the 2W TX, this effort would have been
much less involved.
But it all makes sense. NASA must assure the safety of the
Shuttle ISS system, and these procedures all make sure that the
material, plans, procedures and operations are thoroughly
reviewed and are as safe as possible.
Hope that helps.
Bob, WB4APR
