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!