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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 ------------------------------ 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 ------------------------------ 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 ------------------------------ 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 ------------------------------ 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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