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(meteorobs) Pro/amateur cooperation in support of Deep Space 1 mission
This is an email from local Boston MA USA amateur Ralph Pass, retired space
scientist and serious CCD imager. An *amazing contribution*, Ralph! This is
a little off-topic for 'meteorobs', but perhaps others on our list may have
the available time and equipment to contribute images as well...
PLEASE NOTE: Ralph is not a current reader of 'meteorobs'. If you follow up,
please MANUALLY put 'rppass@rppass.com' in the "Cc:" line of your reply.
Clear skies,
Lew Gramer
------- Forwarded Message
Date: Thu, 13 Sep 2001 18:44:49 -0400
From: "Ralph P. Pass III" <rppass@rppass.com>
Subject: Deep Space 1 (DS1)
Deep Space 1 (DS1)
Deep Space 1 is the first of the New Millennium missions flown by JPL for
NASA. This mission was to test and to demonstrate twelve new
technologies. Three of them were ion propulsion, autonomous navigation,
and autonomous flight software. The spacecraft was launched on October 24,
1998 with its primary mission to fly by Asteroid 9969, Braille, also known
as 1992 KD, on July 28, 1999. The ion engine used Xenon as its fuel source.
The ion propulsion worked very well. The autonomous software worked less
well. The encounter with Braille was fraught with software glitches and
anomalies. The only image obtained was 15 minutes after closest approach
and represented a disappointment that images from closer distances were not
successfully acquired. The 15 minute delay changed the distance from 28 km
to about 13,000 km. See:
http://photojournal.jpl.nasadot gov/cgi-bin/PIAGenCatalogPage.pl?PIA01344
for the image that was taken.
This concluded the spacecraft's primary mission. The mission was extended
and was targeted at two comets: Comet Wilson-Harrington in January 2001 and
Comet Borrelly in September 2001. However, the on-board star tracker
failed on November 11, 1999. Normally this would have ended the
mission. However, JPL managed to jury-rig a star tracker using the imaging
system. During this time, however, the spacecraft missed critical
thrusting to get to Comet Wilson-Harrington. The spacecraft could and does
continue on to Comet Borrelly.
DS1 is scheduled to fly-by Comet Borrelly on September 22/23, 2001. It
will fly-by within a week of so of the Comet getting to perihelion. It will
become the seventh spacecraft to visit a Comet, and the first in more than
16 years. In preparation for the encounter, JPL has been collecting
information about Comet activity. This is used to final mission planning.
Since the fly by with be at roughly 30,000 miles per hour, the amount of
dust and small particles around the Comet will determine the chances of
survival. Mission planning is trying to 'guess' how close to go and
still survive.
Data has been collected with the 60" telescope on Mount Palomar and with a
24" telescope at the JPL Observatory. Time on professional telescopes is
limited and JPL's telescope was taken down for engineering work in August
2001 and will not return to use until after the DS1 encounter with Comet
Borrelly. At that point requests were sent to people trying to get images
to fill in the gap. Many people promised but only one (so far) has
contributed data.
I am that one and have now contributed three sets of data. Since I have
nothing else to do at 4am, I thought I could assist. Little did I know
that I would became the primary source of data for the final encounter.
My data is being provided to the Mission Managers within hours of
receipt. Data is now showing a decrease in comet brightness (even though
it is still approaching perihelion) and by implication, a decrease in dust
production. If real, this is actually good news for the mission as this
will enhance the chances of the spacecraft surviving the fly-by.
With just about 10 days to go, I have been asked for as much data as I can
provide, particularly over this coming weekend and during the encounter the
following weekend.
This weekend will be interesting because the JPL team has gotten one night
of time on a 'little' telescope out by San Diego: The Palomar 200". The
JPL team wants data collected as close together in time as possible between
the 200" and my 10" to calibrate the two results. With as much awe as I
had for this magnificent telescope as I grew up, it is now astounding to be
participating in a science program where my data is being used side by side
with data from the 200". This truly boggles my mind!
So with a 10" telescope based in Andover MA [USA], science is being done!
Ralph Pass
------- End of Forwarded Message
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