🚀 go-pugleaf

In article <93025.205009IO20721@MAINE.MAINE.EDU>, Michael Petersen <IO20721@MAINE.MAINE.EDU> writes:
>Could someone tell me if NASA has successfully deployed the high-gain
>antenna on Galileo yet?   

As newscaster Chevy Chase used to say:

"This just in from Madrid.  According to doctors attending 
Generalissimo Francisco Franco,  the former head of state 
is valiantly hanging on in his fight to remain dead."

No.

[It's been 39 days since the last time I posted this answer 
to this question.]

>I heard that their most "aggressive" attempts
>would occur after the the last Earth flyby.

True.  Still going on.

Bill Higgins                           | Sign in window of 
Fermi National Accelerator Laboratory  | Alice's bookstore:
Bitnet:      HIGGINS@FNAL.BITNET       | "EVER READ BANNED BOOKS?
Internet:  HIGGINS@FNAL.FNAL.GOV       |     YOU SHOULD!"
SPAN/Hepnet:      43011::HIGGINS       | Gee, I hope it doesn't become
                                       |   *compulsory*.

In article <93025.205009IO20721@MAINE.MAINE.EDU>, Michael Petersen <IO20721@MAINE.MAINE.EDU> writes...
>Could someone tell me if NASA has successfully deployed the high-gain
>antenna on Galileo yet?   I heard that their most "aggressive" attempts
>would occur after the the last Earth flyby.

The recent hammerings have not opened the antenna.  The first hammering
attempt turned the ballscrew an additional full rotation, but it has
not budged since.  Despite 13,000+ hammerings at different frequencies
and at various antenna temperatures, the ribs are still stuck.   One last
attempt will be made by spinning up the spacecraft from 3 rpm to 10 rpm
in March, but this is not expected to do much.  March has been designated
as the deadline to open the antenna.  After that the focus will be
on the Ida flyby in August and a low gain antenna mission.  One other
event that may open the antenna is the Jupiter orbit insertion in December
1995.  The solid rotor motor will fire for an hour and the resulting 
vibrations may jar the antenna loose, but this is to be considered a long shot.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Every once in a while,
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | try pushing your luck.
|_____|/  |_|/       |_____|/                     |

In article <26JAN199316452669@kelvin.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes:
>In article <93025.205009IO20721@MAINE.MAINE.EDU>, Michael Petersen <IO20721@MAINE.MAINE.EDU> writes...
>>Could someone tell me if NASA has successfully deployed the high-gain
>>antenna on Galileo yet?   I heard that their most "aggressive" attempts
>>would occur after the the last Earth flyby.
>
>The recent hammerings have not opened the antenna.  The first hammering
>attempt turned the ballscrew an additional full rotation, but it has
>not budged since.  Despite 13,000+ hammerings at different frequencies
>and at various antenna temperatures, the ribs are still stuck.   One last
>attempt will be made by spinning up the spacecraft from 3 rpm to 10 rpm
>in March, but this is not expected to do much.  March has been designated
>as the deadline to open the antenna.  After that the focus will be
>on the Ida flyby in August and a low gain antenna mission.  One other
>event that may open the antenna is the Jupiter orbit insertion in December
>1995.  The solid rotor motor will fire for an hour and the resulting 
>vibrations may jar the antenna loose, but this is to be considered a long shot.
>     ___    _____     ___
>    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
>    | | | |  __ \ /| | | |     Jet Propulsion Lab |
> ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Every once in a while,
>/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | try pushing your luck.
>|_____|/  |_|/       |_____|/                     |
>

Have people thought about combining hammering with the orbit insertion?
I think hammering when whole spacecraft is vibrating due to motor
firing would shake loose about anything :-) .. Or is it impossible
due to some minor technical detail? 

- Jarnis <jarnis@mits.mdata.fi>

In article <1993Jan27.133908.16401@prime.mdata.fi>, jarnis@mits.mdata.fi (Jarno Kokko) writes...
>Have people thought about combining hammering with the orbit insertion?
>I think hammering when whole spacecraft is vibrating due to motor
>firing would shake loose about anything :-) .. Or is it impossible
>due to some minor technical detail? 

I don't think that would be a wise thing to do.  The motor firing has be
done at a precise time with the spacecraft in the proper attitude.  If the
hammering was done during the motor firing, and the antenna was to pop
open, it could change the spacecraft attitude enough to really mess up the
orbit insertion.  Besides, the spacecraft will very busy as it is during
the orbit insertion, collecting the probe data, performing a 1000 km Io flyby 
and collecting science data on Jupiter.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Every once in a while,
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | try pushing your luck.
|_____|/  |_|/       |_____|/                     |

In article <27JAN199316252809@kelvin.jpl.nasa.gov>,
baalke@kelvin.jpl.nasa.gov (Ron Baalke) wrote:
> 
> I don't think that would be a wise thing to do.  The motor firing has be
> done at a precise time with the spacecraft in the proper attitude.  If the
> hammering was done during the motor firing, and the antenna was to pop
> open, it could change the spacecraft attitude enough to really mess up the

What's to say it won't pop open anyway?

> orbit insertion.  Besides, the spacecraft will very busy as it is during
> the orbit insertion, collecting the probe data, performing a 1000 km Io flyby 
> and collecting science data on Jupiter.

Will there be an attempt to open the antenna AFTER Galileo is in orbit (on
the assumption that the firing may have jarred things loose)?

I dont know about hammering the HGA during the Re-entry manuever
although it seems like a little risk may be called for.  besides
program the probe to stop hammering if you get more then n
ball screw rotations, where n<5.  

Also isn't there a plan to hammer the HGA during the probe deploy?

pat