Question: Soyuz Descent Module Landing System

Hello. Can anyone provide any details about the sensor that is
mounted on the base of the Soyuz descent module for detecting the
approach of the vehicle to the earth's surface, and at the appropriate
time, sending the signal for firing the module's landing retro-rocket
motors? I was told by a friend that it is a gamma-backscatter device
with a 10-curie cobalt 60 (Co-60) source, but I am having trouble
remembering some of the details I heard. I understand this is the
reason for the radiation trefoil marking that is visible on the base
of the module whenever the module is seen resting on its side on the
ground.

Specifically:

1. Is Co-60 the radioisotope that is used?

2. What is the activity of the source (in either traditional or SI
units)?

3. What is the exposure rates to individuals seated in the descent
module (in either traditional or SI units)?

4. Is the device equipped with a shutter and what is the exposure
rate to people near the base of the module during recovery operations?

5. Is the heat shield jettisoned before landing in order to expose
the sensor (and other things) prior to landing?

Since Soyuz is known to come down in a variety of places and there
always seem to be folks who look like curious civilians standing
around [and yes, if one came down in my neighborhood, I would be one
of them :)], it would seem you would need to think about dealing with
a radiological problem in addition to the usual spacecraft handling
pleasures (hypergols, ordnances)

Thanks in advance for any information.

John Pelchat

(John Pelchat) wrote in message . com...
(John Pelchat) wrote in message . com...
Snipped Can anyone provide any details about the sensor that is
mounted on the base of the Soyuz descent module for detecting the
approach of the vehicle to the earth's surface

A few days after I posted my question, I found a passage in Asif
Siddiqi's book "Sputnik & the Soviet Space Challange" that discussed a
"gamma altimeter" as part of the Soyuz landing system. I did a google
search on that term and found:

http://www.rtc.neva.ru/english/k_spusk.htm

Good weekend to all

John

Sam Seiber wrote in message ...
rk wrote:

Hi,

I don't have the answer to your question but recently saw a book (I will
be borrowing it soon, so I don't know if it's any good, perhaps someone
here has read it) that might be useful:

Soyuz: A Universal Spacecraft
Rex D. Hall and David J. Shayler
(c) 2003

Springer-Praxis books in astronomy and space sciences.

-- rk

Well rk, I don't think I have ever seen Springer-Praxis put out
a bad book. I have purchaced several, and have been happy with
them all. At something like $40 for the Soyuz, I am going to
wait a few weeks before ordering this one.

Sam Seiber

Sam & RK

Thank you for the great lead on the new book. I have a number of the
Springer-Praxis books and enjoyed them all. Cripes almighty though,
they are expensive. Fortunately a birthday and Christmas are around
the corner ;)


John

rk wrote:

You're very welcome. I should get a loaner copy soon and I'll write
a summary review, I'm interested in comparing US space technology,
which I'm pretty familiar with, with non-US hardware and software
for similar functions and applications.



I'm looking forward to your review, as I'll probably try to get a copy
through intra-library loan...Soyuz is a very interesting spacecraft ,
and since I presently have a 1/30th scale model of one within hand
reach, and a grand total of 8 1/144th scale Soyuz and 2 Progress models
within 30 feet of me, I can probably spring for the $1.00 library charge
to get it...then on to that Apogee Dyna-Soar one....

Pat