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Date: Thu, 28 Mar 91 01:50:33 -0500 (EST)
Subject: SPACE Digest V13 #310
SPACE Digest Volume 13 : Issue 310
Today's Topics:
Shuttle Status for 03/21/91 (Forwarded)
Ion Propulsion
Re: Rifles
Re: Hi-G devices (arrows)
GEOMAGNETIC STORM INFORMATION UPDATE #1 - 24 MARCH
Magellan Update - 03/20/91
Soviet space tour request
Administrivia:
Submissions to the SPACE Digest/sci.space should be mailed to
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----------------------------------------------------------------------
Date: 22 Mar 91 07:36:13 GMT
From: mips!swrinde!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@apple.com (Ron Baalke)
Subject: Shuttle Status for 03/21/91 (Forwarded)
KSC SHUTTLE STATUS REPORT - THURSDAY, MAR. 21, 1991 - 10 a.m.
STS-37/GAMMA RAY OBSERVATORY - ATLANTIS (OV 104) - PAD 39-B
LAUNCH - APRIL
WORK IN PROGRESS:
- Interface verification tests between the orbiter and the Gamma
Ray Observatory payload.
- Inspections of orbiter components in the aft compartment due to
water intrusion.
- Preparations for loading hypergolic propellants into the or-
biter.
- Launch Readiness Review.
WORK COMPLETED:
- Countdown Demonstration Test.
WORK SCHEDULED:
- Loading hypergolic propellants into the orbiter beginning late
tomorrow.
- Flight Readiness Review March 26-27.
STS-39/DoD - DISCOVERY (OV 103) - OPF BAY 2
LAUNCH - LATE APRIL, EARLY MAY
WORK IN PROGRESS:
- Rigging of the right hand external tank door hinge housings and
cycling of the doors to retest.
- Thermal protection system operations.
- Functional tests of the external tank doors.
WORK SCHEDULED:
- Roll to the Vehicle Assembly Building Monday.
STS-40/SPACELAB LIFE SCIENCES 1 - COLUMBIA (OV 102) - OPF BAY 1
LAUNCH - MAY
WORK IN PROGRESS:
- Testing connections for the payload.
- Electrical connections of space shuttle main engines.
- Preparations to service the ammonia boilers.
- Orbital maneuvering system pod functional tests.
- Thermal protection system operations.
- Preparations to replace the S-band antenna.
WORK SCHEDULED:
- Installation of the Spacelab Life Sciences payload into the or-
biter this weekend.
WORK COMPLETED:
- Installation of the three main engines.
STS-40 SOLID ROCKET BOOSTERS - VAB
Optical alignment of the hold down posts on the mobile
launcher platform is in progress. The left and right aft skirts
have been removed from the mobile launcher platform. Earlier this
week, gauges attached to the aft skirts and hold down posts gave
readings about the loads that are not understood. The concern is
that the posts are not aligned properly. The aft skirts are
scheduled to be restacked on Saturday. Schedule impacts are cur-
rently being assessed.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
------------------------------
Date: Wed, 20 Mar 91 13:12:08 EST
From: Babe Magnet <DFOSSUM%UOTTAWA@acadvm1.uottawa.ca>
Subject: Ion Propulsion
Greetings from the Great White North!
I am a final year undergrad in physics. In one of my courses, we were assigned
seminar topics relating to charged particle dynamics--I got ion propulsion of
space flight. I was wondering if anyone would be able to suggest to me some
good references for this subject? Possibly something downloadable from
somewhere. I figured someone subscribing to this list would be able to direct
me to some fab-o info and that I could really shine on D-Day because of it.
Please write to me directly. My address is: DFOSSUM@UOTTAWA.BITNET.
Thanks Muchly,
Daniel Fossum.
------------------------------
Date: Fri, 22 Mar 91 15:08:30 EST
From: John Roberts <roberts@cmr.ncsl.nist.gov>
Disclaimer: Opinions expressed are those of the sender
and do not reflect NIST policy or agreement.
Subject: Re: Rifles
>From: henry@zoo.toronto.edu (Henry Spencer)
>Subject: Re: railguns and electro-magnetic launchers
>In article <1991Mar21.080855.27560@leland.Stanford.EDU> zowie@leland.Stanford.EDU (Craig DeForest) writes:
>>Lesse: the bullet of a `typical' hunting rifle comes out at the
>>speed of sound, after accelerating from rest inside the (1m) barrel.
>Actually, Mach 1 is a pretty slow bullet, more typical of pistols than
>modern rifles. 700-1000 m/s is more typical for a high-velocity rifle.
>That's also a reasonable velocity range for medium-performance artillery.
>1000m/s in a 5m barrel is an average of 10000G, and the peak will be
>somewhat higher.
As an example of the high acceleration of chemical launchers, and of the
working of mechanical devices at high accelerations:
The fastest commercial load I know of is the Remington .30-06 Springfield
"Accelerator". It uses a large powder load and a small (55 grain = 3.56 gram)
bullet. From the promotional literature:
Remington's new "Accelerator" has an incredible muzzle velocity of 4080
fps [1244 m/s]. A sub-caliber (.30-06/.224) bullet is seated in a plastic
sabot and put into a standard .30-06 metallic case. The plastic sabot
separates within 14 inches of the muzzle and falls to the ground....
Given that most Remington .30-06 rifles have a 22-inch (.56 m) barrel,
and using the formula a = v^2 / (2 * d), this gives a minimum peak
acceleration of 1.38E6 m/s^2, or about 140000 G. (I know that sounds
high, but I checked the calculations several times. Correction or verification
welcomed.) It's impressive that the plastic sabot holds up under that load.
John Roberts
roberts@cmr.ncsl.nist.gov
------------------------------
Date: Fri, 22 Mar 91 17:24:16 EST
From: John Roberts <roberts@cmr.ncsl.nist.gov>
Disclaimer: Opinions expressed are those of the sender
and do not reflect NIST policy or agreement.
Subject: Re: Hi-G devices (arrows)
>From: korpela@stew.ssl.berkeley.edu (Eric J. Korpela)
>Subject: Re: railguns and electro-magnetic launchers
>Organization: Cal Berkeley-- Space Sciences Lab
>In article <1991Mar21.080855.27560@leland.Stanford.EDU> zowie@leland.Stanford.EDU (Craig DeForest) writes:
>>
>> This is an interesting comment on material strength:
>>arrows are typically light wood (pine?) or sheet metal or plastic,
>>with flimsy plastic or real feathers at the back. All of these
>>materials withstand the initial (and much stronger final) acceleration
>>in the arrow!
>You materials strength comment is a bit inaccurate. You've probably
>never seen a wooden arrow explode when someone attempts to fire it
>from a compound bow. Even a 45# compound bow has the ability to
>shread wooden arrows (usually doing some damage to the arms of the
>bowman.) Arrows used in high pull bows are usually hollow aluminum
>shafts.
> /\ korpela@ssl.berkeley.edu Internet
> /__\ rioch BKYAST::KORPELA 42215::KORPELA DecNet
> / \ of Chaos korpela%bkyast@ucbjade Bitnet
> (_____________________ <aka Eric Korpela>
I've shot cedar arrows with a friend's 50-60 lb compound bow with no
trouble. Actually, for a given transfer of kinetic energy, a compound
bow will treat an arrow more gently than a recurve. (Though cedar arrows
tend to be lighter than aluminum, and thus shoot faster.)
Good cedar arrows are *very* hard to find nowadays. I suspect that's because
they're more prone to warping than aluminum arrows.
One of the big compound bow gimmicks of recent years is the "overdraw" kit.
This allows you to shoot arrows several inches shorter than your natural draw
length, making the arrow shorter and lighter for faster travel and a flatter
trajectory. A "typical" rating for a good compound bow is 210 feet per second,
or 250 feet per second with overdraw. (Standard draw lengths are usually in
the range of 26-32 inches.)
So a good compound bow shoots an arrow with a "typical" minimum peak
acceleration of ~270 G, and if the target stops the arrow in a distance of
3 inches (typical targets are made of high-density foam plastic), then
peak deceleration might be on the order of 2700 G.
John Roberts
roberts@cmr.ncsl.nist.gov
------------------------------
Date: Sun, 24 Mar 91 01:51:12 MST
From: oler%HG.ULeth.CA@BITNET.CC.CMU.EDU (CARY OLER)
Subject: GEOMAGNETIC STORM INFORMATION UPDATE #1 - 24 MARCH
X-St-Vmsmail-To: st%"space+@andrew.cmu.edu"
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
INFORMATIONAL MAGNETIC STORM UPDATE
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
08:30 UT, 24 March
-------------
ATTENTION:
Severe geomagnetic storming has been observed over most North American
middle and high latitude stations. Boulder reported a K-index of 8 for the
03-06 UT period. Severe storming continues in progress. Intense magnetic
fluctuations are occurring which are capable of producing induction
effects.
The interplanetary shock speed has been corrected to a value of 800
km/s. Satellite protons (at geosynchronous altitudes) shot up by 11,000
particle flux units (p.f.u.) to 43,000 p.f.u. at greater than 10 MeV on 24
March at 03:50 UT. The shock arrived at 03:42 UT with a vengeance.
Boulder recorded a magnetic SSC with an amplitude of 183 gammas. Local
measurements have been more closely examined and show a rapid rise-time SSC
measured at 180 gammas. Severe storming began shortly thereafter. The
Polar Cap Absorption event has reached an absorption intensity of 46.5 dB's.
The protons at greater than 100 MeV are now measured at 16 p.f.u..
Southerly middle latitude locations have observed auroral activity.
Low latitude auroral activity is believed to be visible, although no
confirming reports have been received yet. Most of the activity to 08:30
UT confirms the presence of bright red auroral patterns mixed with greyish
arcs. Auroral oval expansion has occurred. Further southward migration is
possible. It is difficult to say whether or not North American observers
will be able to spot auroral activity tommorrow after dark. The storm
could begin detensifying at that time. For interested observers, make the
effort to check. The activity could still be present. It all depends on
the duration of the storm, and that is very difficult to predict.
Significant HF disruptions have occurred. Middle latitudes are
experiencing significant levels of absorption, fading, flutter, distortion
and noise. Near blackout conditions exist over many middle latitude
locations (particularly the more northerly middle latitudes). Very poor to
near blackout conditions are expected to continue throughout the next 12 to
24 hours. Some improvements can probably be expected thereafter (25/26
March).
PLEASE REPORT AURORAL OBSERVATIONS, SIGNIFICANT HF SIGNAL ANOMALIES OR
DEGRADATION, VHF BACKSCATTER COMMUNICATIONS, OR OTHER UNUSUAL PHENOMENA TO:
OLER@HG.ULETH.CA. PLEASE INCLUDE THE DATE AND TIME OF THE OBSERVATION
(LOCAL AND UT TIME), LOCATION (LATITUDE/LONGITUDE), AND A BRIEF DESCRIPTION
OF THE PHENOMENA OBSERVED.
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
------------------------------
Date: 20 Mar 91 21:38:49 GMT
From: swrinde!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke)
Subject: Magellan Update - 03/20/91
MAGELLAN STATUS REPORT
March 20, 1991
The Magellan spacecraft and its radar system are performing nominally.
All of the STARCALS (star calibrations) and DESATS (desaturations) yesterday
were successful. Only one star reject was noted.
Magellan is now in its 1260th mapping orbit. The capture rate of data on
the Earth is still about 94%, which is the equivalent of 1182 orbits on the
ground. This covers almost 65% of the total Venus surface area.
The weekly mapping command sequence, M1079, was be sent to the spacecraft
and is now executing. This upload contained a command sequence to perform
Test #2 on the Flight Tape Recorder "A."
Mission controllers are now uploading the final files to reload the AACS
(Attitude and Articulation Control Subsystem) Memory "B". Two of the seven
uplinks have been accomplished this morning. This process will restore full
redundancy to the AACS memories, and includes fault detection which will
quickly isolate the memory in the event of a chip failure.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant.
/___| | | | ___/ | |/__ /| Pasadena, CA 91109 |
|_____|/ |_|/ |_____|/ |
------------------------------
Date: 22 Mar 91 18:36:20 GMT
From: hub.ucsb.edu!ucsbuxa!3001crad@ucsd.edu (Charles Frank Radley)
Subject: Soviet space tour request
HELP :-
$ 5 K to Baikonur is more than I wanna spend right
now......
But I am entering the British Airways sweepstakes, and
there are a LOT of tickets being given away ! The grand
prize is ANYWHERE (specified in advance).
Moscow seems to be the closest BA city to Leninsk.
If I win a ticket (they are awarded in pairs, anybody
wanna double up ?) how much does it cost to get to
Baikonur from Moscow ? Can you set up a tour like
that ? How long will it take ? I wanna see a launch of
course !
Outbound travel will be on April 23 rd 1991 (not
negotiatble - competition rules).
HELP !
Send any e-mail to charles@stb.info.com
------------------------------
End of SPACE Digest V13 #310
*******************