Recovery pic

FOXSI launch day, part III

Now that the rocket flight was over it was time for another adventurous flight, this time via helicopter.  

Rockets launched from White Sands land far uprange, about 40-60 miles (60-90 km) from the launch rail.  The payload sheds all its accessories during the flight: the two motor stages that give the payload its boost into space fall off after burnout and the nose cone (the tip of the rocket) falls away during the descent to allow the parachute to open.  These components (or what's left of them) also land somewhere in the desert.

Our mission was to find the payload, split it into two sections, and bring these back via two helicopters.  Besides the Navy helicopter pilots and photographer, there was room for four of us.  The team ended up as Ed (Wallops electrical engineer), Paul, Steven, and me (after Säm graciously turned down a seat in order to let Steven or I go).  We were warned that this could be quite strenuous work -- each of the payload sections weighs 200-300 pounds, and the landing site could be a small ravine or a difficult incline.  Luckily, FOXSI made this easy for us by picking a nice flat stretch of desert to settle on!

Even without the rollercoaster emotions of the flight and the anticipation of recovering FOXSI, the helicopter ride (my first ever!) would have been memorable.  It took about a half hour to reach the landing site, during which we were treated to a spectacular view of the desert.  200 feet below us the sand dunes and vegetation created strange geometrical patterns on the desert floor.  I was able to see for the first time how vast the famous white sands really are, the peculiar fine white gypsum powder giving the illusion of a giant salt basin.  I saw tracks that looked like lake/river beds and creeks, obviously long dried but perhaps occasionally bursting back to life during rare desert rainstorms.

And then we found FOXSI.

I am sure that the mesquite bush our payload chose to land in is the thorniest one in the desert.  It looked innocent enough, until we dove in to clip the parachute cords, and then its spines cut us at every move.  I like to think of it as sneaky little FOXSI getting in a few last jabs!

But the landing was perfect!  After FOXSI was finished observing the Sun, a shutter door closed over the telescope.  The door carries a metal honeycomb structure that acts as a crush bumper, and it is this structure that the payload lands on.  FOXSI landed on end on its crush bumper and then fell over on one side, snuggling itself into the thorny mesquite bush for us to find.  (If the parachute had not opened as expected we would have found a hole in the ground instead of a happily resting payload.)

The work was straightforward: Ed vented the compressed gas carried in the payload for fine pointing maneuvers, we unbolted the two halves of the payload and broke all the electrical connections between them, and one by one we loaded the halves onto the helicopters using the large rocket cradles we had brought with us.  We covered the open ends with large tarps taped to the rocket skins, and then we were on our way!

Except we needed a pit stop.  The payload sections were so long that they stuck out the sides of the helicopter.  The high air turbulence outside the helicopter ripped one of our protective tarps to shreds, exposing the detector end of our telescope and causing electrical connectors to fly around wildly.  We landed again in the desert and used an entire roll of heavy-duty tape to tape directly over the end of the payload, creating a protective cover.  This proved good enough to make it back to the launch complex with no further damage.

Back at the vehicle assembly building, the triage began.  We were jubilant about the success of our payload, but now was the time (with all equipment, people, and memories present and intact) to figure out what things had gone wrong.  We checked our alignment with the rocket pointing system to see if we could have been horribly off target, and found that this was unlikely.

We examined our telescopes and electronics for damage…and found a little.  One of the seven optics modules stuck out a little farther than the others.  This happened because a glue joint holding that optic in place had failed, allowing the module to move.  Of course, with any payload damage a big question is whether it was the launch or the landing (a huge shock!) that caused it.  In this case we *think* the shift happened at launch, although it's difficult to be sure.

The other optics modules all looked just fine, and the next day we did one last X-ray alignment test to check that everything was still functioning.  With the exception of the one shifted module, everything looked exactly the same as it had before the flight.  This is fantastic news, because it means we have a mostly intact payload which could be used again for future flights!

…which brings us to the big question of what's next!  FOXSI has a second flight funded, tentatively scheduled for 2014.  For that flight we have planned some upgrades to the instrument, but those plans did rely on recovering the payload in one piece (which it mostly is).

As we begin to look at the data I'll attempt to post some updates about our progress.  First, though, is a big push to finish my dissertation in time to graduate this semester!  And one more piece of exciting news -- I'm told that the official launch photos and videos are on their way to us soon.  I will post these as soon as I get them!

Thanks again for all the warm wishes and support from all our FOXSI friends!

FOXSI launch day, part II

The countdown continued.  I felt strangely detached.  The countdown hit zero.  On the TV screen there were smoke and flames and the rocket leapt up off the ground.  Before that moment FOXSI had always seemed kind of small on the launch rail, at least compared to the gigantic rockets you see in pictures of spacecraft launches.  But at that moment FOXSI was huge and powerful and dangerous, an object visible from all over the desert.

The sound hit us later, having taken several seconds to travel the miles between the launch rail and our building.

FOXSI was in the air, climbing slowly.  The second stage motor ignited, there was another bright flash, and FOXSI shot off unbelievably fast, now truly on its way to space!

I was floored by what I had just witnessed, but now there was work to do!  The most important step was to send the uplink command to turn on the voltage to our detectors.  If this command were to fail for any reason then our X-ray cameras would not work.  It was for this reason that I was inside, watching the launch on a TV, rather than outside with the others -- I wanted to be focused and ready for this crucial step.   At 30 seconds after the launch, I sent the command and watched the data to see that it had registered.  It did, and the detectors immediately began to respond.

There were about 70 seconds more to wait for FOXSI to get to space, the shutter door to open and reveal our telescope, and the pointing system to find the Sun.  We would start observing when the rocket was about 150 kilometers (100 miles) high, well above the dense parts of the Earth's atmosphere.  The other team members ran back in to take their places by my side and we eagerly watched our screen to see the data streaming in…

…and we saw nothing.

Well, not exactly nothing.  There were a few X-ray hits here and there on our detectors, but the rate was quite small and they did not come from a concentrated spot on the Sun as we had expected.  We looked at each other and calmly made the decision to switch to a backup target.  Säm (our principal investigator and the "driver" for our payload) sent the command to change targets.

The second target showed no improvement.  Again, no concentrated spot appeared, but only random hits here and there.  At this point it looked as if the mission might be a failure; with no recognizable image at all it would be difficult to prove we had even been looking at the Sun.  Despite this, we moved on to a third target. 

 This target showed nothing much as well.  Now about three minutes had gone by, which is half our observation time, and all of our best prospects for finding an X-ray source were gone.  The rocket reached its peak height of 300 kilometers and then started on its way down.

We switched to a fourth target, one of two we had programmed in as last resorts.  (We had appropriately nicknamed these "Hail" and "Mary.")  We did not expect much, if any, emission from these targets, but they were regions on the Sun we hadn't looked at yet.

And suddenly there it was!  The count rate jumped up significantly, and an X-ray image started to build up.  Excitedly, we yelled at Säm to center the image!  He sent the command to do this, and the image disappeared.

That's right, it disappeared.  We had gone the wrong way!  If you ever needed an "undo" button, this was the time!  And luckily we *did* have an undo button.  Säm steered us back to the target and we found our image again.  (Later, we found that a problem in the way we had written our software was responsible for our wrong turn.)  We were in instant agreement not to touch anything more; we stayed right where we were for the last minute of the observation time.

And then it was done.  The rocket was descending back into the atmosphere.  The shutter door closed over our optics.  I sent the command to begin the shutdown of our detectors.  The parachute opened and FOXSI slowly continued its descent back to the desert sands, so much more carefree and calmly than the manner in which it had left.

Steven gave me a high-five that nearly broke my hand, and that began the celebration…we had done it!  FOXSI had done it!  We had made a focused image of X-rays from the Sun, the first ever made in this particular way in this energy range.  At that point we did not really understand what it was we had seen, but the important thing was that the instrument had worked.

Later we would learn that we had been extremely lucky.  The solar object we imaged was not a sunspot, as we had expected, but a solar flare in progress!  It was a small flare, but it appeared at just the right time and in just the right place for FOXSI to see it.  Without this flare, it is possible that we may have had no recognizable signal from the Sun.  Hail Mary, indeed…

So what to make of our other targets?  Why did we see no, or very little, X-ray emission?  There are several possibilities.  The active region targets could have been either cooler or fainter than we expected.  Our sensitivity could have been reduced for an unknown reason.  The quiet-Sun signal could have been extremely faint or even nonexistent.

But here is where the solar flare we caught really comes into play.  With this flare we can do a cross-calibration of our instrument with an existing spacecraft, RHESSI.  With this proof of a working instrument we can then make a case for what the X-ray flux actually was from the quiet Sun (and from the active regions).  If we find that there was no detectable emission, this is in itself an important science result.  But there may be emission after all.  As I mentioned, there was a very small rate of X-rays even before we saw the flare.  At this point it is not clear whether this signal was from the Sun or from the background X-ray flux that persists throughout the solar system.  It will take a tremendous amount of work to properly make that distinction!

But I digress…at this point there was a helicopter about to arrive to take us to the landing site and recover our payload.  We grabbed a couple bags of gear for the ride and took off for the helipad.

Stay tuned…part 3 will describe the journey into the desert to retrieve FOXSI!

FOXSI launch day, Part I

Normally it would be a challenge to get me out of bed at 4:45 am.  But not on this day -- today we were ready to launch our rocket!

Everyone assembled at the missile range at 6:15 am.  This included the FOXSI team, the NSROC team -- some from Virginia and some from White Sands --who had built our rocket systems and managed the flight, engineers from the local university who provide telemetry, and Navy representatives, providing range and safety support.  Most of these team members would stay in the block house during the flight.  This is a sturdy building about a quarter mile from the launch rail where mission control takes place.  With 10-foot-thick walls and even thicker ceilings, this bunker is well insulated from the fiery blast about to take place.

But most of the FOXSI team would move to a building a couple miles away where data is received and sent during the flight.  From here, we can watch the data streaming in real time using software that we had written and send uplink commands to the experiment.  The best thing about this building is that it's far enough away that you can actually watch the launch outside!  (Not the case for the block house.)

The reason for arriving so early was that there were two more sequence tests to get through -- one horizontal (with the launch rail lying on its side on the ground) and one vertical (launch rail up, ready to launch).  After the launch rail "went vertical,", the rocket motors were armed (i.e. ready to fire).  After this, nobody is allowed to the rail except in case of emergency.

The other reason for getting an early start is that a few hours before the launch roadblocks went up all around the base.  The main road, highway 70, which leads from Las Cruces to Alamogordo and cuts through White Sands, was blocked.  The White Sands National Monument was closed for the morning.  Roads to the uprange section of the missile range were cut off.  All this was to make sure that FOXSI could not hurt anybody when it launched or when it landed!

The sequence tests were passed without incident.  During each of these tests, as before, we practiced the countdown and the commands we would send during the flight.  For the last time, we ran through scenarios for decision-making during the observation.  In the downtime between tests, we checked solar activity, took some team photos, ate a lot of food, and watched videos of previous launches.  The mood was excitedly nervous, but calm.

Twenty minutes before the flight a final check-in was called.  We put on our headsets in order to communicate with the rest of the team, got our software up and running, and got ready for the real deal.

Ten minutes before the flight the countdown began.  At this point we filled out a checklist of various temperatures, voltages, and tests to make sure that our experiment was working and ready.  If any of these checklists items looked incorrect, we would have the option to call a "hold" (five minutes at a time) or call a postponement of the launch.  There was a flurry of discussion as a few of our temperatures looked marginal, with one out of range.  We debated whether to call a hold, but decided that the deviation was acceptable.  (This proved to be the right decision, as all temperatures came within range in the several minutes before launch time.)

We were asked for our "go" status and we responded…GO!

In the block house, Lupe continued the countdown, her voice broadcast over loudspeakers in our building.  On one wall of the building, a garage door was rolled up, giving everyone on that side a clear view of the launch rail.  Most of our team gathered there to watch the launch.  There would be plenty of time to run back in before the observation interval began.  I, however, stayed inside, and I'll tell you why later.

I'll leave off at this cliffhanger for now…stay tuned for part 2, a description of the launch and flight!

FOXSI's successful flight!

I've now spent almost a month in the desert, and I've never seen it from this perspective before.

"This perspective" is 200 feet above the ground, staring at the white desert sands from the jump seat on an open-sided helicopter as we fly to the landing site of the FOXSI rocket to recover the payload.

FOXSI flew today, and it was one of the most exhilarating experiences I've known.  Considering nothing else, witnessing the launch of a space-capable rocket would be enough to make a day exceptional.  Participating in the flight, turning on the instrument, and making decisions about the flight in real time makes the day one to never forget.

To say there were tense times would be an understatement.  Data coming back mid-flight showed discouraging results and we had to switch to all of our backup emergency targets before seeing an unambiguous X-ray image that we could interpret.  To understand this harrowing process, see my previous post on the challenges of making split-second decisions!

Once we finally saw it, the X-ray image was unmistakable, and we knew our mission was a success.

More details will follow (I promise!) telling you all about the experience, but for now I'd like to thank all the coworkers, family, and friends who gave such crucial support during some very tough times in putting this mission together.  In particular, without Andy Sybilrud I am sure this flight would not have had such success, and the FOXSI experiment owes much to him!

Mission almost accomplished!

We have worked for four years to get to this point and today we got to see our rocket standing up on the rail, ready to launch.

It feels good.  It feels good to have passed so many hurdles and have gotten to the point we are now.

A few people have asked me what we expect for tomorrow, whether we expect to have a successful flight.  The answer is yes.  Everything we've seen from our testing here indicates that our systems are ready to go.  The caveat: there is still plenty that can go wrong.  Sounding rockets are by nature a risky business, and we've heard several stories of failure.  On one flight, the data downlink didn't work and they couldn't record any data.  On another, the alignment between the experiment and the guidance system shifted and they weren't able to look at the Sun.  On another, a grating shook loose and no useful data could be taken.  Some rockets have to be terminated shortly after launch.  Despite all these possibilities, we remain very optimistic that the rocket and experiment will work as planned.

Whatever happens tomorrow, I'm very proud we got this far.  I work with a wonderful team, and we built a wonderful instrument.  Tomorrow I hope to show you screenshots of never-before-seen solar data!  

Launch time is 11:55 Mountain Daylight Time.  Recovery via helicopter will take a few more hours, and after that I will try to update you all as soon as possible.

Boom!

The rocket is on the launch rail!

On Monday and Tuesday they loaded up the motors first and then the payload.  We are now completely integrated on the rail, and almost ready to launch.  We put all our equipment on the launch rail -- liquid nitrogen, our cooler, a couple digital meters and a power supply -- and strapped it down so that it will stay put when the rail goes vertical.  (As for whether all that equipment survives the launch…well, we'll see…)

Then we did a "boom" test.  Everybody gets away from the rail to a safe distance, and we remotely turn on all the devices on the rocket and on the rail.  Electronics create electric fields around them and can interfere with each other, so this test is to find out if any electronics are affecting the circuitry that fires the rocket engines.  The test is passed if nothing at all happens when we power up.  If the test is failed…well, that's why they call it a "boom" test!

We also spent most of the day today troubleshooting an RS-232 connection from our cooler on the rail to the safe house a few miles away where we will stay during the flight.  With several kinks successfully worked out today, we are now able to run the cooler remotely.  (Important because nobody will be allowed near the rail on launch day.)

Tomorrow: more sequence tests, including a vertical test.  Right now the rail is horizontal on the ground so that we can access all the parts of the rocket.  A hut over the rail shields it from the sun, wind, and rain.  In order to "go vertical" the hut will roll all the way back and the rail will be slowly raised up from its end so that the rocket is pointed almost straight upwards.

Launch time is 11:55 MDT on Friday.  Less than two days to go!

Decisions, decisions

Suppose you had worked for four years to build an instrument and only got six minutes to fly it.  (That's how long our observation time will be during the rocket flight.)  Now imagine all the things that could go wrong during those six minutes!  How would you react and fix it?  You have built a new instrument that has never been in space before, so you're not completely sure how it will behave.  You're looking at targets that nobody has ever been able to see before, so you don't know for sure what you will find.  And you have only minutes to interpret what you are seeing and make any necessary adjustments.

Your palms should be sweating by now, and ours are too.  That's why we spent most of the day today establishing a plan for exactly what we will do during our rocket flight.  We dreamed up every scenario we could think of and made a written plan for decision-making during the flight.  We have two different targets we will point at on the Sun, and seven identical X-ray detectors.  An example scenario: what do we do if some of the detectors show high noise levels?  If a detector is noisy we have ways to fix this.  But what if we mistake actual X-rays for noise and "fix" it in a way that cuts out the data completely?  To avoid this awful outcome we decided that we will only make adjustments to one or two detectors, and leave any others as noisy as they want to be.  That way we hedge our bets and have the best shot at getting good data from at least some detectors.

Another example: our first target is going to be an active region on the Sun.  Active regions (sunspots) are the bright areas where most solar flares come from.  This region should emit large amounts of X-rays, so it will serve as an important check that the instrument works.  But what happens if we don't see anything from the active region?  Do we then go on and point to the quiet region of the Sun as we had planned?  Do we move to another active region?  Do we stay longer on the same one?  Do we try to make adjustments to the pointing?  All these choices were carefully talked over and hotly contested today, and we emerged at the end of the day with a clear plan for our flight.

This blog post has been way too serious so far, so I will finish off with a picture of our project manager trying on the rocket skin: 

Tomorrow we load the rocket onto the launch rail!

Shaken, not stirred

The El Paso airport is starting to feel very familiar.  Not only have I flown in or out of it 7 times already this year, but I've spent a decent amount of time in the arrival lounge, where I'm currently waiting for another member of the FOXSI team to arrive.  Las Cruces is about an hour north of El Paso, and there are not very convenient ways to get between the two cities, so I've been shuttling people back and forth as needed.  (The alternative is a very expensive taxi ride!)

The guy I'm waiting for now is Saito, a grad student at the University of Tokyo.  He and Ishikawa did most of the preliminary work on the FOXSI detectors in Japan, and they are both joining us for the rocket launch.  Later this week two more FOXSI friends, Jose and Jason, will show up, just in time for the flight on Friday.

That rounds out the team that's already here: our fearless leader Säm, who splits his time between Berkeley and Switzerland and brings us delicious Swiss chocolates whenever he visits; Steven, our project manager extraordinaire who was instrumental in writing the FOXSI proposal and getting FOXSI going in the first place; Ishikawa, who flew in from Japan two weeks ago to help out during the integration process; Paul, the head of mechanical engineering at SSL (aka rocket MacGyver); and yours truly, providing detector work and an endless supply of corny jokes.  Not able to join us are are two SSL engineers who have been vital to the project -- David and McBride.  They will be missed!

But on to the exciting news -- FOXSI has passed our vibration test!  Those of you who have been closely following the blog since February (that's you, Mom!) will remember that one of the important steps in getting the rocket ready for launch is to shake the living daylights out of it to make sure it can withstand the high stresses it will experience at launch.  After the vibration test we take the rocket apart and test out all the various systems to make sure nothing came loose.  And in our case our post-vibe tests were successful, with no apparent problems.  This is one of the last major milestones we needed to clear before launch, so at this point there are very few potential obstacles in our way!

This week we will start loading the rocket onto the launch rail (the structure that it launches from) and practice running the entire sequence of operations remotely while the rocket is on the rail.  Hopefully that will mean some awesome pictures coming soon of the rocket on the rail, depending on when the Navy photographer can get them to us.  And then...Friday is the big day!

FOXSI is revived and so is the blog!

It's been way too long since I updated this, and much has happened!  I'll try to make up for lost time and fill in some details along the way.  But we'll start off with the short version:

After returning from White Sands (and taking some well-deserved vacation), we went back to the heart of the problem: our broken detector boards.  With a couple exceptions there was no way to save the old ones; the readout chips had fractured and were unrepairable.  So we started over from scratch.  We had a lot of help along the way from the extended FOXSI team:  Our friends in Japan provided us with many more detectors and readout chips, enough to make two full sets of FOXSI detectors (a flight set and a backup set).  Chris and Rhonda helped in the painstaking job of gluing the pieces on the boards.  (This is not just a matter of slapping some glue on the pieces and throwing it on…this is epoxy applied via syringe underneath a microscope.)  Ishikawa made a return trip from Japan to help with the detector testing.  Even with all this help there was many a late night spent at the lab troubleshooting, taking data, and improving the readout system.  Two new detector sets is twice the work of one, and even one ain't easy…

We were able to get a launch date for the fall, and so here we are again in the desert.  White Sands is much like I remember it…the weather is warm, the sky is beautiful, and the sunrises and sunsets over the mountains are absolutely breathtaking.  The faces remain the same too -- when we pulled up to the Vehicle Assembly Building to unload the truck we were greeted by what now seem like old friends.

The new launch campaign brings a more prepared payload.  As a team we are more experienced; we've done most of this once before and are better equipped for it.  The experiment is more ready as well, since we used the first time round to work out most of the kinks.  This means we have been using our evenings and weekends to see a little more of the desert, to explore the area, or for some of us, to get some good work done on our dissertation…

This week will get us past many of the major milestones, so wish us luck!  If all goes well we will fly the rocket the morning of November 2.  That's just around the corner, and every day FOXSI is looking more and more like it is ready to fly!

...and the promised pictures!!

I did promise you pictures, didn't I?  :)  Here are some photos taken by the authorized photographers at White Sands.  In addition, Steven's got some pictures of the cracked detector system parts on his FOXSI blog, along with some other shots he took outside the range.

The wrapup and the rebuild...

I last left off with the unhappy news that we're pushing the launch.  But I don't want you to think that's where the White Sands work ended...in truth we had much, much more to do that week!  Here's what happened:

When we decided to delay the flight we also decided to go ahead with the next steps of integration and vibration, as a practice run.  We'll have to redo these when we come back for the real deal, but doing them now gives us a chance to identify and fix problems early.  Integration is the process of connecting our experiment (the payload) with the rest of the rocket (systems for data telemetry, pointing control, and recovery, among others).  These parts were made by a rocket team from Wallops Island, Virginia.  Not only did we physically connect everything and make sure it fits (remember, we had some troubles earlier when we tried this with the first piece...) but we also tried running the power, data, and communication through their systems just like it will be during the flight.  We did several sequence tests, where we run through everything in order as if we are doing the launch...except of course we don't launch anything.  :)  Most of these tests were easy as our system is relatively simple to integrate, but we did have to work out a couple more problems in mating various skins and sections together.

The next step was vibration!  As I told you before, a vibration test is done on a shake table that simulates the shaking the rocket will feel during launch.  Passing this test is absolutely essential to the health of the mission because it means that nothing will break or come loose during the launch.  Many things could go wrong in a vibe test: parts could break, connectors could detach, bolts can come out as if an invisible hand is unscrewing them!  We've never vibrated the electronics side of our payload, so this test served an important purpose.  (Imagine if we came back in August and THEN found that we couldn't pass a shake test!)  Fortunately, the test was a success! All the detectors (well, the ones that were still working after the accident...) showed no damage in the vibe test and still worked just as well afterward.  What's more, there was no change in the alignment of the optics, despite the shims and regluing.  So I'm happy to say that once we rebuild the detector system, all major obstacles to launch will have been cleared!  (Yes, there are always more things that can go wrong, but this takes care of all the obvious areas for concern.)

There was one final step for our work in White Sands, and that was to ship everything back to Berkeley.  Things were a little melancholy last Tuesday as we packed everything back up and loaded up the Fedex truck.  A day later, we unloaded the truck in Berkeley and FOXSI was officially back home!  So what's next?  Well, we have to start over by rebuilding the detector system, but we can use everything we learned along the way, so the process will be much quicker this time.  We first need to get more detectors from our colleagues at ISAS in Japan; as soon as we get those I will begin gluing them onto new boards.  After the boards are loaded and wirebonded, we will start the process of testing and calibrating them...and then...we will bring FOXSI back to the desert and we will fly it!!!  Right now we're looking at an August launch date; I will keep this blog going in the meantime so you can keep tabs on the rebuilding.  :)

Day 24 (Thursday, March 15)

Yesterday we made the difficult decision to cancel our launch.  Our condition: we have 4-5 working detectors out of seven.  Of these, three survived the cooling accident, and there are concerns that there could be cracks in the readout electronics that may get worse under the vibration of the rocket launch.  There are two new detectors, however, our calibration data for these is minimal (limited to what I could measure in half a day!)  Taking these things into account, it was decided to start over building our detector system from scratch.  This will probably take 3-6 months, so we will try for a new launch in the summer or fall.

I've gotten a lot of questions, so here's some detail of what went wrong in our cooling accident.  We have a cooling regulator that controls the flow of liquid nitrogen to our system.  You can program it to cool to whatever temperature you want.  It knows what the actual temperature is from a temperature sensor inside our system.  Here's the nice part: based on the difference between the actual temperature and the programmed temperature it decides how much nitrogen to allow into the system.  So you can essentially dial in the temperature you want and walk away; it takes care of the rest.  Except, as I found out, you shouldn't do this because it can make a mistake!  It turns out that if the temperature sensor is temporarily disconnected (i.e. if you unplug it and plug it back in) then things go a little haywire and the cooler does not behave properly.  In this case it got confused about what the temperature was and started dumping way too much nitrogen in our system, resulting in much lower temperatures than our system can tolerate.  This actually cracked a couple of components on our detector board, which are not replaceable.  Long story short, we're starting over by building new boards.

Day 20 (Sunday March 11)  Hurting but alive...

More bad news, folks.  We broke almost all the detectors in the cooling accident.  Two of them looked ok on data readout, two looked completely broken, and the other three were somewhere in the middle, with parts working and parts not.  The situation's pretty dire because we didn't think we brought any *good* working spares!  We did bring five extras, but they never worked particularly well in the lab -- that's why they didn't make it into the final buildup.  You better believe there were some long faces around the lab today...one of the worst FOXSI days ever!

But it's not all bad news.  After many attempts to figure out a way to revive the broken detectors we ended up putting in our spare detectors...and found out they work better than we thought!  Two of the original detectors survived the cooling catastrophe, and of the five extras we put in two are working pretty well and we might be able to revive one or two more.  So that gives us at least 4 out of 7 working detectors, with the possibility of more.  Getting these detectors ready will be a ton of work.  They have to undergo a full testing and calibration process...something that took us several weeks at the lab, but here we will need to do it in a few days!  We also have to prepare these detectors for flight by staking down parts and gluing temperature sensors on them.  And add onto that the time we lost (at least a day) in troubleshooting this problem...the race is on!!  It's gonna be a lot of full days and late nights but I am confident we can do it.  FOXSI lives!!

Day 19 (Sat March 10)

Bad news, folks.  Today I learned the hard way not to leave a cooling system unattended.  Our detectors (the parts that make up the camera of the telescope) are meant to be used at -25 degrees Celsius.  To get that temperature we have a liquid nitrogen cooling system that supplies the detectors with just enough nitrogen to keep them at the temperature we want.  This is a great system if it's properly set!  Unfortunately after I programmed the settings I did not double-check that these settings had properly registered, and the cooling system started the cooldown and just kept going...all the way to -190 degrees!!!  As soon as I discovered this I stopped the cooling and shut down all power.  We put a bag around the detector system and flooded it with dry nitrogen so that as the temperature comes back up water won't condense on the electronics.  Now there's nothing to do but give it time to warm up...and tomorrow morning check to see if the detectors still work.  :(  I have the feeling I won't be sleeping well tonight...everybody wish me luck on this one!!

Day 18 (Friday, March 9)

FOXSI just cannot catch a break!  We came in today with the intention of doing a quick and easy operation in the morning.  Guess what?  Not so easy!  The operation was to place the experiment in the hollow metal cylinders that form the outer shell of the rocket, called the "skins" of the rocket.  These skins are just a little larger than our experiment and get quite hot during the launch.  To do this fitting, you have to use a crane to hoist the experiment into the skin, then bolt the skin to a special fitting ring to join the two together.  Well, when we tried this there was a big old gap on one side between the ring and the skin!  (By "big," we're talking millimeters, but that's big in engineering terms.)  It took well into the afternoon to come up with a solution.  The best solution is to ship it all the way back to the facility that made it and have them machine it down.  But this would cost us a few days in the schedule, and we have no room for that!  However, there is a machine shop at a NASA facility nearby that could do the job.  After some frantic attempts to get in touch with them they generously agreed to take care of it right away (late in the day on a Friday afternoon/evening!) and had the job done in a few hours.  (Never met those guys, but I'll gladly buy them a beer if I ever do.)  We tried the procedure again and everything fit like a glove.  Yet another problem arising...yet another problem solved...!  :)

Day 16 (Wednesday, March 7)

Back in the saddle after two days off this weekend in SF.  (Being surrounded by water and people felt so strange after weeks in the desert!)  The last couple days have been occupied with blanketing the entire payload.  The blankets keep everything at their correct temperature...the optics at room temp...the detectors at -25 degrees Celsius.  Keep in mind that outside this environment a fantastic fireball of an explosion is taking place, so thermal isolation is really important!

Too sleepy to write more now...good night, everyone!

Day 11 (Friday, March 2)

Yet another scrub for the Caltech launch!  :( :( :(  This one got much closer -- they had the rocket on the rail and raised it vertical, then aborted about a half hour before launch.  This time the culprit was the high winds…both at the surface and at high altitudes.  If the winds are strong but steady, usually the launch can go as planned, but if there's a lot of direction-changing then it's not possible to fly.

Today we're flying back to California -- thus the sudden blog frenzy since I've finally got a little spare time on the plane to catch up!  This will just be a short weekend trip; we want to get right back here Monday to continue the alignment tests.  I'll be happy for the couple days off, especially since my favorite person in the whole world will be picking me up from the airport!  I haven't gotten to see him much over the last couple of months and I really hope he will come to visit me in New Mexico too!!  :)

I had a late flight so I had a little time to kill in El Paso before heading to the airport.  So I decided to take a little side trip to Ciudad Juarez in Mexico, just across the Rio Grande.  I parked on the U.S. side and walked over the bridge connecting El Paso with downtown Juarez.  The winds were so strong on that bridge that sand kept flying in my eyes!  I only had about an hour to spend in Juarez so I just went for a little walk down the main commercial stretch and stopped for a cerveza in a little bar.  Coming back across the bridge you go through U.S. customs and immigration, kind of like at the airport.

Day 8 (Tuesday, Feb. 28)

Today's the day we had planned on going home, but (surprise!) it turns out there's more work to do!  We've pushed our California return back to Friday to give us a few more days to work out some problems with the optics and the detector system.  Since we're staying longer this means we'll get another chance to watch them attempt to launch the CalTech rocket!  (That's the other team that's here now.)  That's on the schedule for Thursday night / Friday morning.

Some of the most important work was to epoxy (glue) a holder onto an optic that had slightly detached.  This piece holds the optic in the telescope but had come off due to degraded epoxy.  Could this have happened during vibration tests?  As you can imagine, when the rocket launches the instrument gets shaken quite a lot, at amplitudes up to 10 times gravity!  One of the tests we have to do is to make sure the equipment can hold up under that kind of vibration.  So we put it on a special table that mimics the vibration of the rocket to check if any parts break.  This vibe test has been done a couple of times on this optic over the last year…maybe the detachment happened then but we just didn't notice until we tried to install it in the telescope.  Obviously this led to a lot of concern about the state of the other optics, but we checked them all and they all have a good layer of intact epoxy.

Day 5 (Saturday, Feb. 25)

Not much to report today -- we spent almost all day getting images from all the optics.  Unfortunately we found two detectors that suddenly stopped working.  :(   We'll have to pull these off and do some individual testing in the lab.

Oh one more note -- breakfast today was delicious chorizo and eggs on an outdoor patio at a cafe overlooking the old historical town square.  :) :) :)

Day 4 (Friday, Feb. 24)

After a few late evenings and with the prospect of a 4am launch to watch, we slept in today and showed up to the base in the afternoon…where we found out the launch is scrubbed (canceled)!  So that team's launch is slipping, and if everything checks out they'll probably go sometime next week instead.  We're scheduled to briefly return to California next week, so we might have to miss it.  :(

On the plus side, the alignment problem with most of our optics is fixed.  Our resourceful engineer Paul fashioned some small pieces (shims) to fit just underneath the piece that holds the optics in.  These are very thin pieces of varying thickness, so by placing them all around the optic you can ever so slightly change the angle of the optic so that it's pointing right onto the detector.  Getting the combination of pieces right and fitting them amongst all the other hardware on that fixture is not an easy task, and it took most of the day and evening yesterday. One optic has more severe problems and will need some more personal attention.

With that settled, we moved on to checking the alignment using X-rays instead of a laser.  For this test we built up the detector package (the cameras) on the telescope tube…this is the first time that the optics and detectors have been installed at the same time.  We then used a high-power X-ray generator to illuminate the optics and took an image of this.  The result was just what we wanted to see: an almost-perfect circle on the detector plane!  This is the first real FOXSI image and represents the culmination of years of work, and was especially gratifying for me to see since most of my efforts have been spent getting these detectors to work!

Day 3 (Thursday, Feb. 23)

Yesterday more of our team arrived and we got down to business!  First was to set up the long aluminum tube that holds our experiment and start putting in the "optics."  These are the parts of the telescope that reflect and focus X-rays.  Unlike visible light, X-rays are hard to reflect: they usually pass right through materials or else they get absorbed.  To reflect them you need to reflect at a very small angle off of an extremely smooth and precise surface.  Our telescope has seven optics and each of them has seven mirrors nested together within it.  Producing these mirrors and finding a way to line them up together in a secure way without distorting any of them took years and a lot of effort, and we have our NASA colleagues from Alabama to thank for all this hard work!

Unfortunately we almost immediately ran into our first big problem.  (Well, ok, our first big problem HERE at the base; I'll tell you some other time about all our trials and tribulation during the design, testing, and calibration phases…)  We found that our telescope is not well aligned, meaning that the optics are not pointing precisely at correct points on the detectors (X-ray cameras).  We found this by pointing a laser at the optics and placing a piece of paper where the detectors will go so that you can see the focused pattern, or in this case the UNfocused pattern.  The offset is not so bad that the experiment won't work, but we'd like to do better!  So we spent yesterday and today trying to come up with a way to fix the alignment.

Some exciting news: we're overlapping by about a week with the previous sounding rocket team.  They're scheduled to launch very late Friday night / early Saturday morning (around 4 am)…and we can go watch!  We unanimously agreed that the chance to see a rocket launch, even if it's not ours, is well worth staying up til the wee hours of the morning…and we have plenty of work to keep us busy til then!

Day 1 (Tuesday, Feb. 21)

Yesterday the "advance team" of Steven and I arrived in New Mexico!  The closest airport is El Paso, Texas, which is right on the Mexican border across from Ciudad Juarez.  To get to where we're going you drive about 45 minutes north along the Rio Grande to Las Cruces, where we'll be staying.  From there, you drive east over a pass through a small mountain range, out into the desert valley where the White Sands Missile Range is located.  It's real desert!  Around you, you see only a few desert plants, an occasional tree, the craggy mountains in the distance, and a whole lot of absolutely clear blue sky without a single cloud.  At night the stars are vivid and there's a whole lot more of them than I'm used to seeing from San Francisco!

White Sands Missile Range is a Navy base and NASA has an area they use for sounding rocket flights.  That means several layers of rules to follow…those of NASA, the Navy, Orbital Sciences, and NSRC (the company that NASA contracts with to integrate and fly the rockets).  We've navigated through that web to get access to the base and permission to use our radioactive sources, X-ray generator, and lasers.  This week we'll find out if all those hurdles have been cleared.   One of the biggest rules is, no photos!  But they do have a couple official photographers who can take pictures for us, so I'll post those as we get them.

Today we met many of the folks who work in the NASA part of the base; everyone was very helpful, with several people jumping in to help us unload our two trucks that met us there with all our equipment and the parts of the payload.  We got everything unloaded, unpacked, and set up…tomorrow the real work begins!

Intro

Welcome to Lindsay's FOXSI blog!  This isn't an official project blog, just something I'm throwing together so friends and family can keep up on my adventures in the desert.

A little intro:  FOXSI is an experiment that has an X-ray telescope and camera to make X-ray images and spectra of the Sun.  FOXSI was born in three places: the Space Sciences Laboratory in Berkeley, California, the NASA/Marshall Space Flight Center in Huntsville, Alabama, and the Institute of Space and Astronautical Science in Sagamihara, Japan.  All these pieces are being put together right now at the White Sands Missile Range in New Mexico, where FOXSI will launch on a sounding rocket at the end of March!  The information we get from this 15-minute flight will give us feedback on our technology and allow us to look for never-before-seen signals from the quiet part of the Sun.

We'll be out in White Sands from late February to early April for the preparations and launch.  The flight is planned for March 30…stay tuned to see how we do!