russ
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Internal account of Comet Borrelly encounter, from one of the spacecraft team
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Sep 28 02:56 UTC 2001 |
Date: Tue, 18 Sep 2001 23:55:48 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Time for an Update )
DS1 Update ( Time for an Update )
We've been at a dead run for the last couple of days.
The spacecraft is healthy and I've been watching it
like a hawk. We're using about 36 sec of thruster ontime
each day. That translates to 30 or so gm of propellant.
The navigation seems to be going well. We have excellent
agreement between trajectory estimates made by several
different folks, using several different methods.
The delta-DOR data I talked about us getting a while
back came in and agreed with everyone else.
We did have to change our estimates of where we think
Borrelly is, but that's not too surprising.
We can measure the spacecraft trajectory with great
precision using the radio doppler. The comet is a fuzzy
ball that has to be tracked optically. Now that we have
navigation pictures from the spacecraft, we can
triangulate and greatly improve the position we have for
the comet.
We've been using the Ion engine to gently correct our
trajectory, running it for a few hours at at time,
and coasting in between.
Shyam is saying that the comet is showing up within a pixel
of where we expect it to be in the optical navigation
images.
The trajectory currently would take us a few hundred km
from the desired aimpoint, but the way things look right
now, it should be no problem putting the spacecraft where
we want it to go.
All of this is good news. Things get more and more
sensitive as we get closer and it gets harder and
harder to correct the trajectory, so we have to watch
our step.
We finally got some credible information about the thruster
thermal limits and discovered that we can only do about
a 5 meter/sec burn without overheating the thruster valves.
If we need more than that, we'll have to break the burn up
into pieces with several hours of cooling time between.
We've made good progress on our "worry list". It's down to
a single page now. I spent much of today double checking
the values of each of our long list of flight software
parameters. This evening, I cross checked them against
the values we've been using for our many runs in the testbed.
No real problems found so far.
We've been getting a little press here and there, despite
the bigger issues in the news. A guy from the Public Affairs
office came out today and gave us the lowdown on their
plans. The gist was that the all the comet/science
pictures need to go out through them.
If we get a decent picture, they'll put out a press release.
If we're destroyed by dust, or have some other major problem,
they'll just pretend none of this every happened.
In the unlikely event that we get a bunch of cool pictures,
they'll send out a teaser pic on mon or tue and then have
a full up press conference on thurs or so, provided nobody
is blowing anything up.
If do we get anything, I'll try to describe it as best I can, but
I want to respect their mini-embargo.
The encounter will happen about 3:00 PDT on Saturday. We should
be back on earth point and sending down data an hour later, if
we're still alive.
I was thinking today, as I listened to Brian yacking on the
phone to Shyam about the "VLBI cross track, doppler so and so" that
this is all pretty darned cool. It sounded like real live
spacecraft talk, and I could turn off my brain (it was already
in standby...) and I could remember the wonder I felt as a kid
hearing Gemini and Apollo era space-techno-jargon. I could
remember how I longed to get inside it and understand the secrets
of all that amazing techie stuff, and then my brain came back on
and I could understand every word. And here I find myself,
at the beginning of the 21st century, spending my days
(and nights...) living and breathing this stuff, flying an
ion powered spacecraft around the solar system, zooming
past comets for a living. Pretty darned amazing.
I couldn't dream up a cooler job.
I'd better get some sleep. We've got a few more long days ahead.
Steve Collins DS1 ACS
The web home of DS1 Update is:
http://eis.jpl.nasa.gov/~scollins/acs/index.html
------------------------------
Date: Wed, 19 Sep 2001 21:46:24 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Short Status )
DS1 Update ( Short Status )
Just a quick note cause it's 9:30 pm and I'm short on sleep.
The spacecraft is behaving itself. The navigation solutions
continue to agree and show us on track. It looks like
we can probably do all the targeting we need with a
few short (a few hours) burns of the IPS on Earth point.
(Ed and the NAV guys get extra credit for that in my book.)
Spent today trying to make sure that our testing has been
using all the same files and the identical configuration
that we have on the spacecraft. I was initially pretty
worried about this, but after slogging through all the
details (there are about 50 sequence files that all have
to be right) everything seems to be ok. I spent the
evening setting up to run one last "plugs out" test
with the flight sequences. Hope the space (and testbed)
gods are kind to our little ship.
Steve Collins DS1 ACS
ps Happy Birthday Dad! I love you.
The web home of DS1 Update is:
http://eis.jpl.nasa.gov/~scollins/acs/index.html
------------------------------
Date: Fri, 21 Sep 2001 09:37:30 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Zoomin On In )
DS1 Update ( Zoomin On In )
Thursday 8:30 pm.
Yesterday's "plugs out" test went right down the numbers.
There are no "plugs" of course, but we used the flight sequences
that we have loaded and I did my best to set up the configuration of
the testbed just like the spacecraft.
It took me a fair part of the day to get the data plotted
and evaluate the test. The testbed data system architecture
makes doing what I needed to do almost (but not quite) impossible.
One dream I have for the future after DS1 is to put together
a series of meetings about the shortcomings in the existing
ground data system. I don't know if it will get things fixed,
but at least I can get some complaining out of my system.
John came in this morning with detailed procedure for us to use
if we end up having to do a Trajectory Correction Maneuver (TCM)
with the chemical thrusters. He spent his day yesterday getting
the sequences together. Thanks John. That's one less thing
to worry about. It looks right now like we will be able to
dial in the trajectory for the flyby using nothing but the
Ion engine. That will be really sweet if the nav guys can
pull it off. Nobody has ever done anything like that before.
The spacecraft is still doing just fine up there. Just a couple
million kilometers left to go. We did another set of navigation
pictures and and you can see the comet even in the raw images.
Subtracted and combined, it looks like, well, a comet.
Larry, the lead imaging scientist did a bunch of work on
the photometry today and says we are starting to see the nucleus
now. It's still much smaller than one pixel, but he can tell
by the way the comet is brightening as we get closer, that
lots of the light must be coming from the nucleus.
(It turns out that the coma gets brighter as 1/r while
the nucleus gets brighter as 1/r^2, so if you get close
enough, the nucleus starts to dominate the signal).
That's good news for the navigation, because it helps us
to be sure we're on target and not aiming for jet or something.
The pictures *do* show some kind of asymmetry in the coma.
Or comet currently has a "tail" that's pointing sunward!
One possiblity is that it's a persistent jet near the nucleus'
axis of rotation on the sunward side. What ever it is, it's shown
up in about the same place in lots of frames. Ground
observations say the nucleus is turning about once a day,
so one way to keep a jet fixed is for it to be
close to the rotation axis. Hopefully future pictures
will give us some more clues. Larry seems happy as a clam.
This afternoon, as I was struggling with the data from last
night's test and making predicts of our antenna angles
for telecom, bunch of folks began wandering by. People that
worked on the project and other well-wishers, dropping in
to offer their support. It was quite a contrast from
yesterday afternoon when things seemed deathly quiet
and everyone was working through their last minute worry
lists on their own. My own has come down a lot in size.
Good news, since we're almost out of time and I'm running
out of steam.
Marc admonished me yesterday to try to catch up on my sleep
and to save enough energy that I could *enjoy* the next few days.
Good advice. We won't be passing by this way again.
Tomorrow, we'll take some more pictures of Borrelly and
make our final checks of the spacecraft state before the
big day.
I find I keep looking ahead to the pictures we'll get back and
how cool they will be, but then I remind myself of how much
has to go just right for us to pull this off. Even if our little
team has done it's best, it's still largely up to fate. All it
takes is one snowflake to wipe us out. I really hope that's not
how this story ends. We could do with some good news after
last week.
Steve Collins DS1 ACS
The web home of DS1 Update is:
http://eis.jpl.nasa.gov/~scollins/acs/index.html
------------------------------
Date: Fri, 21 Sep 2001 19:33:00 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( One day to go )
DS1 Update ( One day to go )
The scientists are swarming. Dozens of little laptops
all in a row. I spend a little time figuring out how
the Borrelly velocity maps into the camera field of view.
Mid morning, we fall victim to computer network problems.
We currently can't get access to the AFS directories
where our spacecraft command are held. Arrrrg!
Better today then tomorrow, when we couldn't even find folks.
An hour goes by, a call-in telecon is blasting in the
MSA. The network guys sound wrapped around the axle.
4:40 pm
It seems like they have it back up now.
Hope things keep working. Folks are on alert in case
we have any more trouble.
Tony spends his day double checking the software parameters and
spacecraft configuration. I feel a lot better knowing he's
John has been trying over and over to get the testbed in
a configuration matching the spacecraft. He gets half way
done, and then someone comes in with "one last file" to test.
I've been making last minute checks and trying make a good predict
of the doppler we should see tomorrow. It should have taken about
2 hours of hacking code, but I'm too tired and keep getting
distracted with other questions.
Sam comes by to check in on us. I don't have anything for him to
so we talk for a while about control system design
Brian looks stressed. He's lost hours of time to the network
problem.
Ed looks tired. He's been burning the midnight oil for days
making sure all the Navigation stuff comes together.
Marc hasn't slept a full night in weeks. Night before last,
some bozo who got his pager number paged him with a question
that started "DS1 lost star lock..." Thanks dude.
Todd is motoring along as usual, calm and collected.
- -----
It's almost 7:00pm
In a few hours, we'll start our final trajectory correction
maneuver. It's an IPS burn of 2 1/2 hr that will give us about .5 m/sec.
It should result in a flyby at a distance of about 2200 km.
There is now 20:46 left to go...
The nominal flyby is at 22:30 UTC. That's 3:30 pm Pacific.
We should see the flyby in doppler after a 12 minute one way
light time.
We'll be back on earthpoint about an hour later and will send up
commands to start dumping down the data.
I sure hope the spacecraft survives. I sure hope we get pictures of
the comet. I sure hope I didn't mess up.
See you tomorrow at dawn for the next chapter.
Steve Collins DS1 ACS
The web home of DS1 Update is:
http://eis.jpl.nasa.gov/~scollins/acs/index.html
------------------------------
Date: Sat, 22 Sep 2001 07:14:19 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Big Day at the Donut Shop )
DS1 Update ( Big Day at the Donut Shop )
2001/265-13:41:50
Marc, Curt and I come up the stairs to building 230 together,
looking like a shot out of a movie ( admitedly a very strange movie)
The 3 of us enter the MSA just in time for Joseph to tell us
that we have telemetry in lock after SOB 11.
There comes the first data.
We're mosaicing. Looking for the E58 Earth star.
I watch the "murky pairs" count up higher and higher,
my heartrate following it up. This would be a *bad* time
to lose lock. The telem rates are still low.
THERE. It's seen something. That's a good sign.
I won't really relax till we're fully locked up.
I cross my fingers. We'll be getting high rate data soon.
2001/265-13:59:46
GOOD. We've fully locked up.
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 08:04:11 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 1 )
DS1 Update ( Borrelly Encounter Update 1 )
The ground data system is putting out funny plots.
The data isn't in the correct time order. I've complained
about this several times, but it never seems to get fixed.
I tell Magdy about it and he grabs a computer to take a look.
I feel better about having him around this morning, even though
he has to run off to a wedding in a couple of hours.
I make a run around the telemetry pages verifying that we're in the
proper state.
We shot our last set of navigation pictures last night.
Bob says he has the first picture on the ground.
He fires it off to Shyam and Ed who are running the nav
solutions and to the science team who needs to make
a call about which exposure times to use in the encounter
sequence.
We actually have three versions of the encounter with slightly different
exposure times and image processing thresholds. Depending on how bright
the comet seems to be, we'll pic between the nominal, bright and dim
sequences.
Even unprocessed, the nav picture shows the comet clearly. I'll post
some more of these pictures next week, when the data embargo is lifted.
2001/265-15:01:32
Bob reports that he has the second picture on the ground.
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 10:13:50 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 2 )
DS1 Update ( Borrelly Encounter Update 2 )
The NAV images are showing two distinct plumes, one in the lower right
and one straight sunward. The thing looks just like a comet.
That sunward plume is a little troubling. It's right where we are going...
I crank the numbers. The flyby target is 275 pixels from the nucleus
in the most recent set of pictures. That's well out from where the
sunward plume is visible, but there's clearly some material headed in
that direction.
Most everyone has their DS1 rescue team shirt on today.
2001/265-16:22:02
6 hours 20 minutes to go
I'm hacking on my program to make doppler predicts. I don't have
to get them done, but it might be fun...
2001/265-16:56:53
The latest nav solution has just come in. It shows us
at a flyby distance of 2165 km and about 3.5 km from
the desired encounter plane (B.T) .
The encounter time has changed by about 3 seconds.
A discussion ensues about whether or not we should
make an update to account for it.
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 13:14:29 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 3 )
DS1 Update ( Borrelly Encounter Update 3 )
Sounds like the word from the science team after looking
at the SOB 11 (-10 hr) pictures the science team
has decided to stick with the nominal exposure times.
We get another update from nav. It looks like B-T is about 15 km
2001/265-17:20:17
The nav guys are on and off the phone a dozen times.
They finally agree on a solution and Brian builds a
new set of ephemeris files and Ed and John head off to
the testbed to double check them.
2001/265-18:36:31
The file checkout went fine and the files are being sent up
to the spacecraft as I write.
That's it. unless something wierd happens the spacecraft should be on
it's own.
2001/265-19:57:27
We eat a delightful lunch in the Casini conference room.
Those guys really know how to live.
Folks are wondering around hopefull that we'll get some
interesting science.
It's 15 minutes till we turn off to Borrelly
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 13:33:07 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 4 )
DS1 Update ( Borrelly Encounter Update 4 )
Here we go... Hang onto your hats.
Murky is off.
We've gon to 79 bits/sec and should be starting the turn.
Telecom can see the signal drop.
We're on our way...
I am reminded now that 79 bits per second is very slow.
I just got a telem update. It still shows us pointed
at Earth.
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 14:18:01 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 5 )
DS1 Update ( Borrelly Encounter Update 5 )
We watch the doppler expectantly. I've managed to hack together
some doppler predicts (the nav guys were too busy), but
I don't hve great confidence in them. I give them to
the nav guys anyway, as sort of a side bet.
We get a glimpse of telemetry It shows a bright blob in
the field of view. This should be BMS-1 a star near
Borrelly where we go to park for a while.
2001/265-20:54:14
The next telemetry packet we get shows BMS-1 well inside
the field of view.
So far, my doppler predicts are working out splendidly.
2001/265-21:03:22
Excellent news. We are murky locked on BMS-1.
Plots of the gyro biases show them nice and stable.
The next blob shows the murk star right where we
want it.
2001/265-21:14:19
The doppler shows us starting the first turn to Borrelly
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 14:59:54 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 6 )
DS1 Update ( Borrelly Encounter Update 6 )
2001/265-21:21:44
The doppler shows that we've done the turn to borrelly.
As expected, the telemetry lags far behind.
We get some data that shows the spacecraft in the correct
attitude to put Borrelly in the IR field of view.
The sequence is running up there and doing what it's supposed
to.
2001/265-21:33:44
about an hour to go till flyby...
The nav guys are buzzing around their terminal
arguing about the interpretation of their blob telemetry.
Cool news! Marc reports that PEPE could apparently
could see the solar wind slowing down even before
we turned off of earth point. That will be interesting for the
fields and particles guys.
Folks are getting almost giddy. There's maybe 50 people
crammed into the MSA, all of them talking.
2001/265-21:54:03
We are murking on BMS-2. Everything seems to be working.
The real risk is right at closest approach of course.
That's when we're most likely to be hit by something.
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 15:14:52 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 7 )
S1 Update ( Borrelly Encounter Update 7 )
2001/265-21:58:29
We 're locked up on BMS-2. It locked in 14 pairs. That
means it's not having any trouble.
We seem to be going right down the numbers so far.
2001/265-22:04:01
Charles Elachi, the JPL director, his deputy show up to
congratulate the team. All I can think is, it ain't over
yet guys. We have to survive the flyby and then,
get the data back.
The Nav guys think they can see evidence in the centroid
data that we're still well pointed at the comet.
If so, then the targeting is good.
This is going to be *SO* cool if it works!
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 15:38:49 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 8 )
DS1 Update ( Borrelly Encounter Update 8 )
Ed says: I hope about 10^8 things are right...
2001/265-22:20:58
We have about 20 minutes before closest approach.
I've taped a soccer ball to the top of my terminal
with a "tail" made of kimwipes. It looks beautiful.
It's happening on the spacecraft now. One way or the
other, the dice are being rolled.
The Nav guys are seeing centroid data from the far encounter
and it seems to look good.
2001/265-22:32:02
RSEN should be in control now, tracking on the comet.
2001/265-22:34:15
8 minutes to go
It's hard to tell with the telemetry so slow, but
It looks like we're locked on...
If we get a picture past this point,
we'll have a picture at least 13 pixels across
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 15:56:46 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 9 )
S1 Update ( Borrelly Encounter Update 9 )
We just had to lose the star tracker to do things right...
If we're going to lose it this is when it's going to happen.
Tony comes in with a huge pile of flags he's printed out.
I put on my search and rescue helmet.
He hands them around the room just before closest approach.
The timer counts down and everyone applauds.
The real news is that we still have contact.
Ed has seen telemetry of a blob that's 20 pixels across.
We can't see pictures yet of course, but the image processing
software is telling us that we are seeing something and
it's staying in the frame.
Holy cow! We may actually pull this off!
We're still getting doppler.
We're looking at each other and just shaking our heads.
Every moment we last now, we get safer and safer.
I find it's hard not to think of the events on the 11th and
feel a little emotional. I don't know if this is a
fitting tribute to all those folks, but the two events
will forever be connected in my mind.
The nav guys say the filter used 32 pictures in the
state estimate. That's strong evidence we stayed locked
on.
Now we're getting telemetry again!
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 16:53:37 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 10 )
DS1 Update ( Borrelly Encounter Update 10 )
We're still at a very low telemetry rate, but everything
we're seeing looks very, very good.
The RSEN software had residuals of 10 or 11 pixels.
That implies that it was securely locked on something
and I can see in my data that we were tracking very
close to the nominal ephemeris. That means that the
trajectory the NAV guys started us with was spot on.
2001/265-23:15:24
The doppler shows the turn back to earth is starting.
The traditional jokes about this all being a rehearsal
driven from the testbed go around the room.
2001/265-23:43:1
We're back on earth point. Marc quizzes me about the
gyro biases and their stability. We recompute the off
earth angles and spend a few minutes evaluating the
downlink signal strength. It looks like the spacecraft
is stable on earth point.
Joseph sends the command to raise the downlink rate and
start blasting down the science data.
Man oh man Oh Man OH MAN, I hope we get some good data.
That would be sooooo cool.
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Sat, 22 Sep 2001 18:08:28 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 11 )
DS1 Update ( Borrelly Encounter Update 11 )
Todd Barber, the prop guy points out how cool it
is to be one of the first people on Earth to see these
pictures.
Marc calls for quiet, they've apparently found a minor
timing problem with the post encounter stuff.
Our little pre-cirl script was re-armed too soon.
We run out to the conference room and write the
times up on the board. We're being hyper vigilant
because now the ship is likely loaded with precious
science data.
The data rate changes and the data starts streaming
down. We watch the EVR messages blasting by reading out
Bob has the first snip picture on the ground. It's from 85000 km
It's looks like a comet. It's pretty deep and you can
see detail in the near coma.
Tony and I try to watch murky lock up at the same time we
watch over Bob's shoulder as he brings up the snips.
The next picture he brings up is missing packets.
The third is from 30000km it's stunning.
You can see shape in the shading. These are still the
navigation images.
The next picture looks like a contact binary. It's
probably shadowing. The scientists are buzzing, huddled
around the displays across the MSA behind Brian as he brings up the
pictures for them to see.
Even in these very early images, you can see the jet forming
along one side. This is going to be just stunning.
There is nice soft contour. It looks a lot like an asteroid
at this resolution, but with a plume of material on the
sunward side.
Their thinking 14 or 15 km across for nucleus size.
The next snip makes us scream and clap for minutes.
It shows stunning detail across the whole nucleus.
There is detail in shadow areas, presumably because of
light coming back from the coma.
The scientists are saying stuff like "these early nav snips are
10 times better than the only other comet pictures that exist,
the Giotto pictures of Halley.
Folks, we pulled it off.
Steve Collins DS1 ACS
Realtime updates at:
http://eis.jpl.nasa.gov/~scollins/ACS/borrelly.html#latest
------------------------------
Date: Wed, 26 Sep 2001 14:34:08 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Borrelly Encounter Update 11 + 1 )
DS1 Update ( Borrelly Encounter Update 11 + 1 )
The NASA press machinery is spinning up to hold a big press
conference in the next couple of days. Till then, they
want the release of the pictures and science results
restricted. I decide that the right thing to do
is take the DS1 Update archive off line and hold off
posting anything for a couple of days. The realtime
stuff is pretty much over at this point
anyway and my part of the story will keep.
Steve Collins DS1 ACS
The DS1 Update archive can be found at:
http://eis.jpl.nasa.gov/~scollins
------------------------------
Date: Wed, 26 Sep 2001 14:42:56 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Flyby Night Decompression )
DS1 Update ( Flyby Night Decompression )
What a day today was.
I figured that our odds were maybe 50/50. So many things
that could go wrong, with our sequence, with our spacecraft,
with the environment that close to Borrelly.
I'm reeling. I can hardly believe it. We pulled it off.
We kept our little broken spacecraft together and working
and got science data from deep inside the coma of
a comet.
There it was, big as life on our screens.
Hopefully, we'll hold our press conference and please the world
with the pictures, helping to take their mind off the horror
for minute or two.
With the flyby of Borrelly behind us, that's what I'm
hoping for now.
Steve Collins DS1 ACS
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Date: Wed, 26 Sep 2001 14:47:04 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Back to Work )
DS1 Update ( Back to Work )
Monday Sept 24 2001
Folks wander in after the first good rest we've had in weeks.
There is a glowing article in the LA times. As congratulatory
emails come in, I print them out and tape them on the wall
outside Marc's office.
I spend a lot of time wandering around lost. We get the last
few pictures down and I'm briefly hopeful that we might find
a juicy, close picture of the comet in one of them, but it
doesn't pan out.
Towards the end of the day, I get to play with the science guys,
helping figure out when we took each picture and how far we
were from the comet. The Nav guys will have to do a detailed
reconstruction of the flyby trajectory, but everyone wants a
quick look to compute quotable numbers for tomorrow's press conference.
Steve Collins DS1 ACS
The DS1 Update archive can be found at:
http://eis.jpl.nasa.gov/~scollins
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Date: Wed, 26 Sep 2001 14:45:08 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( The day after )
DS1 Update ( The day after )
Sun Am
I woke up early this morning. Been doing that for a few
weeks straight now and it's hard to stop. I called
in to the ACE and checked on the spacecraft. Everything
was going just fine, so I stuck with my usual sunday
morning ritual: light breakfast, a run to the store
for popsicles and gatoraid and then off to the
Caltech athletic field for a couple of hours of soccer.
Tony and I play hard.
I wander into the lab about 1:00 Marc is there along
with the project scientist, working on details of
the media campaign. I'm pretty sure that's not Marc's
favorite part of being project manager, but when I
catch sight of him between the numerous telecons and meetings,
I can see he's still walking on air. The quote he gave
the press folks last night says it all:
"I can't believe how cool this is,"
That was the only thing he could manage to say for at
least an hour after our first glimpse at the pictures.
At one point Marc shakes his head and says, "We made
10000 decisions and we got all the ones that counted right."
The way Marc is about numbers, I have no doubt that was an actual
numeric estimate. Like me, I think Marc was worried that
we would get one wrong.
I start up a query of the engineering telemetery from the encounter
wander over to the SATVA, the room where the science team has
set up camp. They're all sitting around a big table with their laptops
analyzing the data, talking excitedly in ones and twos about their
specific areas of interest. The bowl of chips contains nothing but
crumbs.
Dave Young is looking at PEPE data. He can see all kinds of interesting
structure in the colorfull plots. At one point he walks Marc through
a complicated diagram he's drawn on the white board, trying to explain
what he sees in his data.
Larry Soderblom is working with the pictures, processing them
various ways to bring out different details in the coma and
jets and surface. He's like the proverbial kid in a candy store.
I hear someone talking about sun angles and slip back to my office
to query the relevant data. I come back with some plots and
talk through what they mean with the folks who care.
I've been looking at the spacecraft telemetry for 3 years now
and to me it's transparent. I can look at a sun angle plot and
see the spacecraft moving in my mind. The science folks
are only here for the week and need help visualizing
where things are mounted on the spacecraft
I look forward to Monday when folks will come back and hear
what we manged to pull off.
Steve Collins DS1 ACS
The DS1 Update archive can be found at:
http://eis.jpl.nasa.gov/~scollins
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Date: Wed, 26 Sep 2001 14:51:58 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( Into the Jaws that Snap )
DS1 Update ( Into the Jaws that Snap )
We all gather in the Auditorium for the press conference.
They show a few of the pictures. Marc says "Earth, meet Borrelly."
W cross our fingers and hope for kindly treatment by the press.
Afterwards, the science team packs up and heads back to their home
institutions. I get the scoop on the DPS science meeting. With a
little luck, I may try to find my way to New Orleans to hear
some of their papers.
In the afternoon, Brian gives me one great piece of news,
they can apparently see stars in several of the comet pictures.
That will be of enormous help when we try to fit together a
precise estimate of the attitude drift and the timing of the flyby.
I've heard there was a massive solar flare. I think tonight I'll
try to go out and see the aurora.
Steve Collins DS1 ACS
The DS1 Update archive can be found at:
http://eis.jpl.nasa.gov/~scollins
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Date: Wed, 26 Sep 2001 15:03:57 -0700
From: Steven M Collins <scollins@airmail.fltops.jpl.nasa.gov> (by way of Steve
Collins) Subject: DS1 Update ( View From a Mighty Hill )
DS1 Update ( View From a Mighty Hill )
I called Navigator Ed up in the desert and the aurora was
a no-show, so Sharon and I spend some time playing with the
Borrelly pictures, enhancing them, making them into stereo pairs
and basically just enjoying them. It's very tempting to...
to eat it because it looks so much like a delicious chicken leg.
No. It is very tempting to just drop everything and
go learn about comets and devote my life to looking
at these pictures and trying to figure them out.
And it was pretty awesome Saturday night to be there,
looking over Bob Werner's shoulder, as he pulled
the images up for the first time.
As I go to sleep, I find I'm amazed that our work has resulted
in something so tangible: an image of something never before
revealed to human eyes. So much of flying spacecraft is based
in pure imagination. Orbits, orientations, probabilities...
I'm forced to imagine the spacecraft's turns in my mind.
We do complex calculations with piles of numbers that hint how far
it may drift on gyros, how much propellant we might have left,
where in the vast sky we can point a field-sized antenna to contact
our imaginary friend with a tiny whisper of radio signal.
I'm impressed that we humans can somehow quilt those mind-images
together and produce a REAL vantage never achieved by any human.
With only our thoughts and a scant few kilograms of metal, we can
scale a mighty hill and see a view no one has seen before.
Steve Collins DS1 ACS
The DS1 Update archive can be found at:
http://eis.jpl.nasa.gov/~scollins
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