Newsgroup: it.hobby.satellite-tv
Titolo: what is a micro thruster?

if it used nitrogen to balance a satellite, how to produces nitrogen in
space with solar cells ( PV)?
what is a micro thruster?

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Nitrogen (or whatever propellant) is stored in tanks, not created onboard.
Micro thrusters (or thrusters in general) are small valves placed in 
suitable locations, such that when opened to release propellant, alter 
the satellite's orientation.  They operate in accordance with Newton's 
3rd Law;  release a small mass at high speed (high pressure) to move a 
large mass at slow speed.
jt

it does calculate and re-calculate   the position of  itself
(nano-satellite) itself everytime it release the nitrogran.
Can a nano-satillite produces nitrogen on-board, and why not it can't
produces throught "elecroniliess" wrong -spelling.
Once it used up , then it can't stay in the same position any more?

    Nitrogen is stored in small tanks for position control.  Once it is used,
that's it.  You can't "make" the nitrogen, no matter how good your electronics
are.  Nitrogen is a chemical element, and you must store it somewhere in the
satellite.  There is a limited supply.  This limit is what sets the lifespan of
most satellites.
Cheers!
Chip Shults
My robotics, space and CGI web page - 
http://home.cfl.rr.com/aichip

 Once it used up , then it can't stay in the same position any more?
            Exactly. When the fuel onboard the satellite gets depleted, the
satellite goes into inclined orbit (where it still can be used for certain
uplinks/downlinks), and then eventually gets "retired".
            Here is some information from SES-Americom:
http://www.ses-americom.com/about/management.html
            Daniel.

 lifespan of most satellites.
OTOH, the solar wind could be used with movable panels to change the
orientation of the satellite, as only a very small force is needed.
The required power comes from the panels of course... This must be
being used already surely?
--
Clifford Heath

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Columbia 515 (322.3) 37.7 West
Columbia Communications Corp. 
Last week Columbia 515 (322.3) 37.7 West was retired.
GE turned off all the transponders
The beacons are still active
It ran out of GAS (Hydrizean, Nitrogen or what ever was used for
station keeping).
scambron

     A much better system uses a conductive tether.  A pair of parallel
conductors run out a few hundred meters or so, shorted at the end.  The
satellite end supplies power to it from a solar panel to create a magnetic
field.  This repels from the Earth's field, causing the satellite to rise in
altitude.  Shorting the tether or applying a resistive load to it creates a
current in it through dynamo effect- it is cutting the lines of force of the
Earth's field now- and lowers its orbit.
    Of course, this does very little to keep it centered on its position, so
station keeping is poor.  But it is a fully electrical system for moving the
satellite around without using reaction mass.  Now, light sails could be
attached to use the very tiny force from sunlight to help keep station... and in
theory, you could tack against the solar wind.
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A good read
The xenon ion propulsion system
http://www.twtas.com/pictures/factorywalk/xips/xipspage.html
Sir Charles W. Shults III wrote:
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 wrote in message
news:3DCF0F0E...@managesoft.com...
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Not sure about this one, but I heard a long time back (mid 80's) of an idea
to stabilise micro-satellites. These were to be piggy-backed very cheaply
onto other launches and literally sprung off the launch vehicle at the orbit
altidude. Tumbling was likely to be a big problem. The particular ones I
heard about were produced by the University of Surrey (UK) to measure the
Earth's magnetic field, so were equipped with large coils orientated in all
three planes. After launch, these coils were to be successively shunted to
slow the tumbling. Cheap, but time consuming.
Won't maintain an orbit, though, I guess. You'd still thrusters, and
hydrazine, or whatever. Ion thrusters need less propellent mass (and more
easily handled), but very high accelerating potentials, which I guess were
not compatible with the low-cost, low size devices.
PeterS.

- creating more than 3,000 tiny beams of thrust. XIPS requires only one
propellant, xenon, and does its stationkeeping job using a fraction of that
required by a chemical propellant system.
it needs something called xenon gas in its payload which means it will run
out eventurally. Can they use propeller with motor. or there is no air, it
cannot push the air.
Can they push a panel up and down or sideway  and backward to gain the max.
(operational/functional Position) ?
henri

    There is no air to use a propeller with- if there were, the satellites would
become flaming meteors very quickly.
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 theory, you could tack against the solar wind.
Well that would be an achievement. What were you planning to use as a keel?
:-)
Igor

    Direction of reflection to control your deflection.
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 wrote in message
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I'm not familiar with the concept of tacking in space, so I figure you would
at least have to neutralise (or considerably reduce) the lateral component
of your force to get any kind of forward vector. A boat has a keel to push
against the water, but I don't see that working in space.
Igor
still puzzled

 still puzzled
    See if you can get your hands on a copy of "Space Sailing" by Jerome L.
Wright (1992, Gordon & Breach Science Publishers).  It has a pretty decent
section on using light pressure for control of the movement of a spacecraft.
The technique was even used during a Mercury flyby (Mariner 10).
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 My robotics, space and CGI web page - 
http://home.cfl.rr.com/aichip
I'll go and see, the library 200m from my house actually has it on the
shelf.
Igor

 ... using light pressure for control of the movement of a spacecraft.
I though space sailing used the solar wind, a stream of particles,
not photons. AIUI, the solar wind produces substantially more force
than reflected photons. Can someone clarify?
--
Clifford Heath