Alice Springs or Bust

This evening, the NCT balloon gondola and support equipment left in a 40′ container for a new campaign.  It will travel by sea to Alice Springs, Australia, whose Southern Hemisphere location will allow us to observe the Galactic Center.  We will follow by air–along with the NCT cryostat–next month.

The adventures and challenges of the eight short months since we returned from Ft. Sumner could fill an entirely new blog.  For now, I’ll leave you with some pictures from the packing process.  Look for updates from Oz in March…

Setting up the crates.

Alan considers the inventory.

It's important to have enough balloon tape.

Working under the hood.

Moving the cradle in and out of the gondola is always a team effort.

The "bug stamp" on our crates indicates that they are safe for export.

Getting closer.

Belinda, not everything gets packed for the container!

The gondola pallet.

Good packing.

Edgar runs the forklift.

Moving out.

The gondola pallet needed some extra balancing.

Loaded!

Leaving for the port.

What’s Next for NCT?

After our very successful Spring 2009 flight from Ft. Sumner, New Mexico, the NCT group is turning its attention toward a more ambitious goal: a long-duration, round-the-world flight from Alice Springs, Australia.  The southern hemisphere launch site will allow us to observe the Galactic Center, which is rich in gamma-ray sources, and the long flight will enable us to make detailed maps of diffuse nuclear line emission in the galaxy.  With its wide-field imaging capability and great energy resolution, this is the science that NCT was designed to do, and we’re excited by the opportunity to push the envelope of discovery.

There are launch opportunities in Australia as early as Spring 2010, and we’re already working to figure out how to make that happen.  A two to three week flight from another continent is no minor logistical undertaking, though, so we’ll have to be smart in our preparation!  Thanks to our earlier-than-expected flight and the good condition of the instrument on recovery, we’re already well on our way.  Still, we have some improvements we’d like to make in the meantime.  NCT ‘09 only flew 10 detectors of a possible 12, so it would be good to be able to fly the full complement.  We hope to make the solar panels lighter and more robust.  We’ll sort out the quirkiness of the rotor.  Finally, there are a number of bars on the gondola frame which bent on landing and will have to be remade.

We’ll be busy looking at the great data we obtained in our Ft. Sumner flight, too.  I have a big pile of efficiency calibration data to reduce and will take some polarization calibrations.  From flight, we’ll need to verify our backgrounds, and then we can start doing imaging and spectroscopy of our two sources, the Crab Nebula and Cas A.  We didn’t get quite enough exposure time on the Crab to expect to measure its polarization, but we should set a solid upper limit and learn some meaningful things about the analysis.

This blog will probably be quiet for a bit, but when the next campaign begins I’ll be back with updates from Down Under!  Until then…

Wrapping Up

A few pictures and notes from the final stages of the balloon campaign…

Recovery

NCT landed upright on a steep hillside several hard miles from the nearest road, so CSBF’s normal recovery trucks were unable to reach it.  Thankfully, CSBF was able to locate a heavy-lift helicopter to extract the gondola, so McBride, Daniel, and Zhong-Kai worked with CSBF to remove the heavy batteries and solar panels so the gondola could be lifted out.  Daniel’s great pictures of the operation are here and here.  The landing bent several bars on the gondola and squished CSBF’s communication electronics pretty badly, but our detectors and electronics made it through intact.  Since the gondola landed upright, the detectors even stayed cold, as the liquid nitrogen didn’t leak out!

Packing

We launched on a Sunday and landed on Monday; due to the difficult recovery, NCT didn’t return to Ft. Sumner until Friday afternoon.  By that point we were all itching to head home, so after some frenzied bubble-wrapping and boxing we left the hangar for good at 5:00 pm on Saturday.

NCT's triumphant return!

Unwrapping...

The skeletal gondola.

Ready to go home...

The engineers have left the building.

Returning to Berkeley

Daniel and I drove the two Budget trucks back to Berkeley over Sunday to Tuesday.  It was a pretty drive along 40, with lots of great Southwestern scenery and nostalgic Route 66 kitsch.  Highlights included stops at the Petrified Forest and the Meteor Crater.  Daniel got a flat tire and I saw a scary accident, but on the whole it was a smooth trip back.

On the road!

Holbrook, AZ.

Old 66 Trading Post and Independent Baptist Church

The Painted Desert

"Teepees," Petrified Forest

Petrified Forest

"Sleep in a Wigwam!"

Lunch at a great 1930s railroad hotel, Winslow, AZ

Meteor Crater!

View from the Meteor Crater towards Flagstaff, AZ

Welcome to California!

Garlic trucks!

Glad to be home.

Final Reflections

NCT's flight path.

With some lucky wind shifts, NCT was able to ride what could have been a short 8-hour flight into one of the longest flights ever launched from Ft. Sumner.  We had some challenges with our pointing and power systems in flight, but problems are to be expected in any experimental program of this size.  We got a lot of great data and have improvements in mind.  Despite the difficult recovery, NCT came back in great shape, and we’re already preparing for the next flight.

On the whole, our time in New Mexico was a great success.  Hard work, experience, and plenty of fortuity produced a nearly ideal outcome.  Along the way, we learned some things about ballooning and plenty about ourselves, and hopefully soon we’ll dig into the data and learn a bit more about the universe.  It’s good to be home, but I’m glad to have shared this experience with such talented colleagues.

We are tremendously grateful for the support of all of the CSBF personnel.  Particular thanks are due to Bill Stepp, CSBF’s head of operations, and Frank Candelaria, the crew chief, for their calm and capable management.  Speaking for myself, I was genuinely inspired by the professionalism, skill, and good humor exhibited by the CSBF personnel throughout the campaign.

Home Again!

There is nothing like returning to a place that remains unchanged to find the ways in which you yourself have altered. –Nelson Mandela

A full (if belated) report on the recovery, packing, and the drive back to Berkeley will have to wait, but for now I am happy to report that I parked NCT safely back at SSL at about 8 pm tonight.  It’s good to be home!

Still Recovering

We’ve gotten news (and pictures) from the downrange recovery crew.  NCT is in excellent shape after landing, with quite negligible damage to the gondola and instrument.  However, it’s situated precariously on a steep slope a hard hour and a half hike from the nearest road.  McBride, Daniel, and Zhong-Kai are working valiantly with the CSBF team to extract the instrument.  Today they hope to stabilize the instrument and remove heavy components like the solar panels and batteries to get under the helicopter weight limit.

Launch Day

8:00 am: NCT launched about half an hour ago and already is up 13 km.  We’ve got another couple hours before we reach our final float altitude (25 miles/40 km).  In the meantime, we’re watching the telemetry and checking that our systems are working as expected…  You can track our flight path here.

Watching the telemetry.

8:40 am: Still heading up.  Shield and detector rates are high, as expected–we’re shortly to pass through the Pfotzer Maximum.

The infamous "GSE stare."

12:00 pm: At float, pointing at the Crab, our primary science target.  We’re having problems with the pointing system.  We’re able to keep in the field of view, at least.

1:45 pm: Quieter here.  Most people have gone home to sleep, with just a few of us left to monitor the data and take care of the pointing.  Manual pointing appears to be working generally, although the data analysis will be significantly less fun.  NCT is heading slowly southwest; no word yet from CSBF on an estimated flight path.  We’re going to have to turn west pretty shortly to go through the night, I suspect.  We were able to see the balloon overhead, though–pretty cool!

NCT flying over the hangar. (Look carefully!)

4:00 pm: Shift change, for those whose presence can be spared.  Thankfully the rest of us don’t have to play the video game of “keeping the source on target.”  I’m starting to look longingly at an inch-thick slice of insulating styrofoam propped up in the corner…

5:30 pm: Ah, even a little sleep in the CSBF lounge helps a lot.  Since I never know when I’ll have a good napping opportunity, I can’t really even resort to caffeine…

Good news from Bill--we can fly longer!

7:00 pm: A stay for NCT?  When we passed over some mountains, we dropped altitude and caught a different wind pattern which is pushing us back north.  Current hope is to fly through the night–we’re discussing sending our crew downrange to extend our telemetry range.  Given our need to point manually, this would be crucial.  We’re switching to some alternate targets for the immediate future–the Crab is now low enough to be attenuated fairly strongly by the atmosphere.

NCT at sunset, through our theodolite.

8:15 pm: We just took a last look at the balloon at sunset.  It was simply gorgeous as the light caught it.  We were able to find with our theodolite’s telescope.  The balloon had more of a diamond shape, and we could see the ribs and even the gondola dangling below…
NCT is heading north at the moment, so we’re prepping for an overnight run.  The downrange crew led by McBride will depart for Winslow, AZ later this evening.  As for me, I hope to head home for dinner and a bit of sleep shortly…

6:00 am: Back at the hangar, and the news isn’t so good.  The overnight crew had to turn off the gondola power last night because the voltage supplied by our batteries was dropping.  (Unfortunately, we had lost our detailed power housekeeping data midafternoon yesterday.)  Our best guess is that one of the two batteries went bad and the other was depleted, because there should have been plenty of power to run through the night.  We’re going to turn on the power again once we think we can get enough power from the Sun.

The other bad news is that CSBF is going to cut us down in an hour or so.  While we’ve had a very fortunate flight path and are still far from the hard boundaries of Mexico and California, we are nearing Pheonix airspace, which we need to avoid.  Also, it sounds like China Lake is planning a GPS jamming exercise for this morning, which is quite frustrating.  (This happened to HEFT in 2005 also, apparently.)

One bright spot in all of this was that our automatic pointing was functioning during the night last night, giving support to the theory that there’s a thermal issue with a couple of gauges in the rotor that was blowing the feedback loop in the daytime.  We’ll certainly be doing lots of tests on our return to Berkeley.

We’ve gotten over 20 hours at float already, so by all accounts this was a very successful flight.  We’re particularly proud of the flawless performance of our detectors and their electronics as well as the nearly error-free performance of the flight code.

6:20 am: Trying to turn on the flight computer–the electronics bay is quite cold after having had everything off all night.

7:20 am: System is up!  We were definitely cheering when we started getting downlinked data again.  We got the flight computer started first, then ran the heaters for a bit in order to get the card cages going.  Presently we’re pointing at the sun and charging the batteries, both of which appear to be working!  This was a really good experience for longer flights to be sure we can take the system up after it’s been cold.

Apparently we weren’t the only ones impressed by our balloon’s appearance at twilight last night–check the links in the comments below for video of the balloon as seen from El Paso.  Thanks, Luis, for finding these!

7:50 am: Woohooooo!  Just got news that CSBF can let us fly quite a bit longer–we may cut down more like 4:00 pm!  The GPS jamming may still complicate our lives, but we’ll do our best.  Power looks good, we’re turning to Cygnus X-1 to take some data.

10:00 am: The Crab is coming back into the field of view!  We’re pointing at the Sun for now, and in a few more minutes hopefully we can start nulling on the Crab itself.  We’re getting close to losing line-of-sight telemetry, but McBride and company are set up and ready to go downrange in Winslow, AZ.  (The loss of LOS is giving us a bunch of momentary heart attacks, because the values coming down in housekeeping are occasionally bizarre, but we figure out what’s happening pretty quickly.)  We’ve also done some background tests by putting our BGO shields in “soft-veto” mode.

11:00 am: Rotor’s holding fairly steadily near the Crab.  We’re keeping an eye on it–we lost automatic pointing about this time yesterday.

12:15 pm: Problems with the power systems.  The batteries appear to be shot while the solar panels are giving strange values, so the total power to the system is sagging dangerously low–we think the power control unit is confused.  We did a total system turn-off to see if it changed, but it came up as before.  We’re just going to try to run until we start seeing abnormal behavior from the detectors.  Balloon science:  edge of your seat (of the pants)!

Pointing is offset at the moment but steady.  We’re just trying to get as many counts as we can…

1:15 pm: System is off due to power problems, likely permanently.  Unfortunately, we were just approaching our period to observe the Crab: the three hours when it was at highest elevation.  Still, we weren’t expecting to get any data today, and we managed some solid pointing.  CSBF is thinking about cutdown points, and our downrange team has left to go try to meet the recovery team.

1:30 pm: Cutdown estimated for 6:00 pm due to current proximity to Pheonix.  CSBF will be looking for cutdown opportunities; we’re not going to turn on again.

5:45 pm: Still waiting for word on cutdown–we’re flying over some rough terrain.  Sounds like there’s a thunderstorm coming into Arizona–hope NCT can handle a night outside!  On the other hand, if we keep heading north, the recovery team can stop by the Grand Canyon…  We’ve been at float almost 32 hours now, an extraordinary flight–particularly because the preflight forecast suggested we might only get eight hours or so!

7:15 pm: Still up–CSBF is actively looking for places to put us down, but the rough terrain and the thunderstorm have complicated their efforts.  According to this unofficial tally, we’re already the longest-flying conventional flight from Ft. Sumner…  CSBF and our recovery team have met and are finding hotels in Arizona.  We’re going to dinner–it’s a bit unsettling having this hanging over our heads…

I’ll get launch pictures up eventually, but in the meantime there are some from the others in the group here and some nice ones from Asad and the EBEX team here.

9:45 pm: We just received word that CSBF is going to cut us down shortly.

10:18 pm: NCT has landed!  The CSBF pilot has confirmed that NCT is on the ground about 30 miles southeast of Kingman, AZ.  Visual inspection will have to wait for late tomorrow when the recovery crew arrives.

First Show

12:30 am: The day starts early when your alarm is set for midnight.  We’re running through our flight checklist, preparing for CSBF to pick us up at 2:30.  There’s a weather briefing at 2:00 to give us a first go/no go for launch.  The winds are completely dead, though, so the surface conditions are pretty much ideal.

Unfortunately, since we weren’t expecting this launch opportunity, we were hustling to get things together in time.  We managed to grab about 2.5-3 hours of sleep before coming back here…

Zhong-Kai and Mark go over the preflight checklist.

1:30 am: Electronics bay is sealed up for flight.  A few more preparations on the cradle are needed–attaching the flight dewar cap and the mylar sun shields.

Daniel with the top mylar sun shield.

Attaching the final sun shield.

1:55 am: We’re tightening down the top mylar shield on the cradle–and we’re ready to roll out.

Ready to go!

2:15 am: Weather looks pretty good, we’re go for flight.  They’re not forecasting as long of a flight as we hoped for, but current forecasts suggest 15-18 hours at float.  What’s likely to force us to cut down is flying too near the Mexican border.  Some high cirrus will cause us to lose some altitude at night, which will mean more absorption, less data.  Doesn’t look like we’ll get a second pass at the Crab, which is unfortunate, but if we can go a full day that’s nothing to sneeze at.

A solid forecast at the weather briefing.

2:25 am: Big Bill just rolled out of the hangar.  The SIP guys are working on their electronics.

2:35 am: Listening to some apropos inspirational music (“All Systems Go–The Launch”, James Horner).  Moving out now!

Ready to attach to Big Bill.

McBride and Boggs keep an eye on things.

Daniel connects the rotor.

3:00 am: We’re on Big Bill and the solar panels are up.

CSBF attaches the SIP, ballast, and crush padding.

3:25 am: Gondola is up, crush pads and ballast are on.  We’re ready to head to the flight line, just waiting for determination of our final layout direction.

The gondola cart, parked.

3:28 am: Sitting down for a moment reminds me how tired I am.  We’re running pretty much on nervous energy only at this point.  McBride is taking a nap on his cot–once we hit float, he and Daniel are driving eight hours away to the downrange station in Winslow, Arizona to give us commanding capability for a longer period.  (He and I had flown there on the CSBF plane Friday to set up our computers.)

4:00 am: Heading out to the flight line to bring the system up and do preflight checks…

Hard hats on for the flight line!

NCT on Big Bill.

Big Bill driving us to the flight line.

On the flight line.

I did the preflight checks up on a lift.

NCT, turned on for flight! (The monitor and keyboard were removed when I left.)

5:40 am: Preflight checks complete, only a couple of little hiccups.  NCT is buttoned up and ready to go.  Surface winds are basically nil.  There’s a bit of overcast.  Balloon’s not laid out yet, though.  Remember, you can watch us on the webcam here.

5:50 am: Balloon is being laid out now.  Sounds like they will begin filling soon after, after which there is no turning back.  Target launch is at 7:00.

McBride watching the fill.

Good humor, waiting...

Nearly filled...

The balloon is released!

NCT has launched!

Into the clouds...

Off on a great journey!

7:30 am: NCT is launched!

Breaking: NCT shows for flight tomorrow, 5/17

We’re formally second in the flight queue, but it turns out we “show” for a possible launch tomorrow.  The winds at float are pretty marginal, so the flight could be short.  The group in front of us required a minimum of 24 hours at float, while our minimum was 6, so: we’re up.  We’ll get here about midnight, pass off the gondola at 2:30 am, with launch potentially at 6:30 am.  (All times Mountain.)

Those interested in following our progress can do so via the CSBF webcam.  The bottom link (“Outside Camera”) is a live feed with a movable camera–please play nice with the other users!  Chances are it’s pointed the best way already.  After launch, follow our flight path–and hope we don’t go towards Mexico or too quickly to California!

Flight Ready!

What a monster week!  We started Monday with the rotor untested, and today we formally notified CSBF that we’re completely ready for flight!  There were quite a few bumps along the way, but stellar effort from everyone on the team got us to the finish line.

Monday we spent some time hanging the rotor, making sure the electronics in it were working correctly.  NCT’s pointing system is rather confusing:  we use a magnetometer to detect the direction of the local magnetic field, then feed that into a servo loop which turns the gondola until the magnetometer is “nulled”–that is, perpendicular to the magnetic field.  Unfortunately, when we hung the gondola on Monday and told it to point, it started spinning in circles!  The feedback loop wasn’t working at all…

McBride zeroes the torque bridge on the rotor.

Tuesday morning, McBride put together a breakout cable so he could inspect the voltages on the magnetometer and the servo loop directly.  The cable was very helpful–we quickly determined the magnetometer was performing correctly, but the “torque bridge” that detects the force on the rotor was not zeroed correctly.  With some fiddling of a potentiometer, we got that fixed.  At that point, we wanted to go outside to test our pointing against some absolute references.  Both our differential GPS and the magnetometer have weird readings in the metal hangar, so we hadn’t had a chance to check their offsets.  Unfortunately, the winds were too high Tuesday for more than a brief solar panel test, so we decided to go out early Wednesday morning when the winds might be calmer.

Wednesday was the most epic day of our campaign so far.  We were up at 4:30 am to get to the hangar by 5.  At six we had rolled out to the wooden A frame to test our systems.  Unfortunately, the winds were still too strong to actually hang the gondola, but we were able to confirm that our differential GPS was giving us correct attitude solutions.  Also, with the help of our theodolite, McBride’s breakout cable,  and a true-north reference on the tarmac, we were able to get a very good zero point for the magnetometer encoder.  We gave up on the winds dying down at about 8 and headed back inside, ostensibly to take a break for some breakfast.

Pushing NCT out into the sunrise.

Daniel attaches the rotor.

Readying the rotor.

The final hurdle to clear before the flight readiness meeting was compatibility.  This is a simulated launch where we connect up all the pieces of the gondola and hang from CSBF’s launch vehicle.  It’s a chance to confirm all the communications electronics are working and verify physical clearances.  We ran into a CSBF guy on the way in, who asked if we could be ready to do compatibility that afternoon.  (With CSBF trying to launch three gondolas and the winds turning around late this year, they hoped to get everyone to flight ready as soon as possible.)  We said we could be.  There was one catch–the engineers had to finish testing an electronics isolation box they had built in a marathon effort the day before!  With no time for breakfast, they set to work while the CSBF riggers and technicians swarmed the gondola prepping it for the afternoon’s test.  After one small hiccup, Jane and McBride got the box working at 11.  Justin and Wei-Che ran to Fred’s to get takeout (we thankfully had pictures of the menu on this blog!) while Mark led the rest of us through our flight checkout procedure.  We rolled open our hangar doors and pushed out to “Big Bill” at 1:00 p.m., right on schedule.

Preparing to attach to "Big Bill," the launch vehicle.

Solar panels up.

Compatibility took the rest of the afternoon.  We hung the ballast hoppers that allow CSBF to regulate our altitude in flight and fit tested the crush padding which should protect the gondola on landing.  We tested our uplinked commands and downlinked telemetry though the tower, just like we will in flight.  We stood around in the sun and waited.  And, at 5:30, we wearily rolled back in and adjourned to Fred’s for dinner.

Attaching cardboard crush padding and the ballast hoppers.

Keeping an eye on things.

Compatible!

The formal final step, the flight readiness briefing, happened today.  Prof. Boggs arrived from the airport, and we finalized our flight requirements and specified recovery personnel.  Looks like we’ll be second in the flight queue behind Fireball.  The weather’s still kind of spotty, but Fireball is planning to show tomorrow morning for a potential launch.  We’re just amazed at how fast things came together for us!  It’s really been an incredible week.

Closer…

We have the rotor!  Testing will commence tomorrow, once McBride returns to us.  In the meantime, we managed to check off lots of little things that we needed to do before flight–strapping cables down, checking the gondola balance, putting on solar shields, etc.  My todo list for the flight computer is rapidly waning.  I’m happy with how it’s running these days, it seems very solid.

To follow up my pictures from the CREST launch, Daniel found a vintage 1992 video about CSBF, Ft. Sumner, and scientific ballooning on YouTube.  It’s an excellent introduction to the launch process!