EUSO-SPB Project

Extreme Universe Space Observatory- Super Pressure Balloon

Rachel Gregg Editor

The payload in front of the launch vehicle, ready for the next stage of the launch checklist.

The preparations for the payload to be lifted by the launch vehicle.

Johannes Eser (Colorado School of Mines) executing the detector checkouts in preparation for a launch.

During the second launch attempt, the payload reached the point of having the solar panels attached to the exoskeleton.

First Launch Attempt

On the evening of April 6th, the EUSO-SPB team was asked to "show" in preparation for launch. During a "show" night the EUSO-SPB team on site and some of the electronic personnel from NASA arrive at the hanger late in the evening, about 11 pm, to start the checklist sequence for launch. About midnight the rigging team arrives and brings the launch vehicle to the hanger to pick up the payload. During this time the weather and risk assessment are evaluated to verify they look good for the launch. This is done about every 2 hours or until a decision has been made that it is too risky to launch. Unfortunately due to the trajectory prediction of the payload and the balloon, the launch was canceled. There was a potential for the balloon to slowly drift in the direction of Auckland or other populated areas on the north island which could cause the risk to be such that the mission would be terminated over the ocean within the first few days of flight. The second show was on April 9th. This show reached the point where the payload was hanging form the launch vehicle and passed the health checks. Unfortunately at 3:30 am it was canceled due to the predicted winds at ground and below 1000 ft were too strong and there was a risk of rain. The next possibility is probably not until next week due to two cyclones to our north and the possibility of rain all this week. Balloon launches rarely happen on the first "show" so now it is a waiting game with much anticipation for the next launch opportunity.

The exoskeleton and solar panels hanging from the launch vehicle during the compatibility test.

Left to right: Mario Bertaina(University of Turin, Italy); Malek Mustafa (University of Alabama Huntsville); Guillaume Prevot (Paris Diderot University, France) and Johannes Eser(Colorado School of Mines) running the flight commands for the detector during the compatibility test.

Rachel Gregg (Colorado School of Mines) and Doug Huie (University of Alabama Huntsville) inspecting the light baffle and removing the plastic that was wrapped around the bottom of the light baffle to make it light tight.

Passed Compatibility!

On March 23rd, the EUSO-SPB instrument passed compatibility and hang test. Following a launch readiness review on March 24th the instrument was officially declared flight ready!

On the 23rd, every subgroup of the launch and science team ran through their procedure for a launch day. CSBF rigging crew went through the procedure for rigging the payload to the launch vehicle, attaching the solar panel skirt to the payload and connecting the flight train including the parachute and balloon to the back of the launch vehicle. On the electronics side, the EUSO-SPB detector and the SIP were turned on. A series of flight commands for the EUSO-SPB and the SIP were exercised. The tests verified that neither instrument interfered from one another during operation. This test also served as a trial run for roll out on launch day.

After several years of hard work and dedication from many Universities around the world, the payload is ready for launch. This fact was once deemed improbable. Launch readiness could not have been achieved without the tireless and incredible efforts of specialists around the world. A huge thank you goes out to all the scientists and engineers in the 8 EUSO-SPB collaboration countries.

More information about the CSBF and NASA side of operations can be found on the NASA blog for the Super Pressure Balloon campaign. In addition, a video of the roll out for the compatibility test can be found <here>.

Angela Olinto (University of Chicago) giving a speech at the VIP reception in a hanger at the Wanaka Airport.

Left to Right: Rachel Gregg (Colorado School of Mines); Debbie Fairbrother, Chief, NASA’s Balloon Program Office; Chargé d’Affaires Candy Green, the acting U.S. Ambassador to New Zealand, and Angela Olinto, University of Chicago in front of the EUSO-SPB payload.

The science team greeting the open house attendees and explaining the science and mission of the upcoming balloon flight.

Mario Bertaina (University of Turin, Italy) explaining the mission to a group of kids.

EUSO-SPB group photo with the NASA team and some of the VIP guests.

VIP Reception

On the evening of March 23rd the Wanaka Airport hosted an open house where members of the community were welcomed to the hanger to see the EUSO-SPB payload and ask the science team questions. Over 200 members of the community came with much excitement about the huge operation happening near the small town of Wanaka. There was then a VIP reception for special guests including the United States Ambassador to New Zealand, Chargé d’Affaires Candy Green as well as Jim Boult, Queenstown Lakes District Council (QLDC) mayor; Deputy Mayor Calum MacLeod; QLDC CEO Mike Theelen. NASA has recently stated that they plan on launching balloons at the Wanaka airport sight for the next 10 years making the relationship with the community all the more important.

The exoskeleton hanging 5 m above the ground while members of the science team and the CSBF crew positioned the white screen underneath the payload.

A forklift lowers the black box, which holds all the electronics and the pdm camera, onto of the red box, which holds the lenses. The exoskeleton stands behind, awaiting the assembly.

Left: Rachel Gregg (Colorado School of Mines) and Doug Huie (University of Alabama Huntsville) in front of the flat field frame they constructed. Right: The frame with the Tyvek on top, ready to go for the flat field test.

Flat Field Testing

On the early morning of March 10th from 4:30 am to 5:50 am the team performed a successful flat field test. This test is used to calibrate the detector by collecting a reference data set when the instrument views a uniform light source. This data set is a way of characterizing variations between pixels. We performed this test by hanging the payload 4 to 5 m above a 12ft x 12ft white screen. A uniform light source was attached to the center of the bottom lens to illuminate the screen uniformly. The payload was then spun 45 degrees between each data set to account for the non-uniformities in the screen and in the background light.

The test was done at such an early hour to minimize the background light since it was still dark outside and the moon had set and to mimic the period during flight that the detector will be taking data. This test is very light sensitive so nearly every light in or around the hanger was turned off or blocked in some way. The CSBF crew was phenomenally helpful during this entire process and the test was complete without any major issues. The data looks good from the first analysis and more detailed analysis is in progress.

The week leading up to the test was remarkably busy. The radiator plate with the electronics and pdm had to gently be flipped over and mounted on the black box that holds the batteries. Then this module was then tested. The black box was then mounted on top of the red box which holds the lenses. The assembly was then secured in the exoskeleton and the full configuration was tested for the third time to make sure none of the wires came loose and the detector was fully functioning for the flat field test.

As shown in the photographs below, a forklift was used to place the black box on top of the red box. The skill of the CSBF team in the fork lift operation was remarkable and greatly impressed the science team. In addition a 12ft by 12ft screen was constructed out of plywood, cardboard paper and three layers of Tyvek.

The lens after soaking in soapy water for 5 minutes

Lawrence Wiencke rinsing the lens with deionized water.

Rachel Gregg using Nitrogen to dry the lens as Lawrence Wiencke, Will Painter and Abraham Neftali Diaz Damian held the lens.

Cleaning the Flight Lenses

In the port of Houston,TX and perhaps somewhere else, the sea containers were fumigated to kill any bugs in the container. Unfortunately, this left the inside of the sea container with a coating of powder with some powder on the Fresnel lenses that will image light from cosmic ray air showers. A few spider webs and dead Texas lady bugs also arrived with our instrument. On March 5th, the lenses were removed from the red lens box, washed, dried and then reinstalled. Here's how we did it.

First we practiced on our backup lenses to test our washing system. We determined that we added too much detergent to the soaking bath but overall the washing process worked. We lined the inside of a plywood box with a plastic sheet and poured in about 40 L of deionized water and added Alconox detergent to make a 1% solution for the soaking bath(for the flight lenses we used a 0.1% solution). We started by blowing off the lens with Nitrogen gas to remove loose dust. We then placed one lens inside this bath on top of some corner spacers and let it soak for 5 to 10 minutes to loosen particles. The lens was then swished around in the water for about 3 minutes in hopes to knock more of the dust off. Then the lens was removed and held vertically over the water. About 4L to 5L of water was used to rinse the lenses very thoroughly on each side. Nitrogen was used to dry the lenses since it is a very clean gas and would not re-dirty the lenses. The lens was held horizontally when it was being dried so that the water being blown off the lens would fall down instead of back on the lens. The lenses were then placed back in their frames and reinstalled successfully. Overall it was about a 9 hour process that ended with the lenses being as clean as they were when they arrived in Colorado from the RIKEN team in Japan that fabricated them.

Left: Rachel Gregg welding part of the Exoskeleton Structure Right: Rachel Gregg with the partially assembled Exoskeleton

Note About the Editor

Hello! My name is Rachel Gregg and I am the editor of this blog. Currently I am a senior undergraduate pursuing a degree in Engineering Physics at the Colorado School of Mines in Golden, CO, USA. I have been involved in this project since June 2015. Right after I completed a required summer course, I talked to the Physics Machine Shop Manager Mr. Randy Bachman. I explained to him that growing up I loved doing hands on work with my Grandpa building dog houses and I was wondering if there was a position open in the shop. From there the rest is history. I spent the rest of the summer TIG welding aluminum and steel projects for the EUSO collaboration under Dr. Lawrence Wiencke. I have welded most of the carts and exoskeleton that are being used on EUSO-SPB. Also, I've welded a stand for the collimated mirror from Marshall Space Flight Center that was used to characterize the EUSO-SPB optics with parallel light. I have had the privilege of traveling to various places. In Lamar, CO, I learned about the project and helped with some data acquisition. In Delta, UT I was on the laser campaign that is used to test the triggering of the detector and is used to determine the efficiency of the detector when it sees light. The lasers are used to simulate cosmic ray showers, just going the opposite direction. In Palestine, TX I assisted in preparing the instrument for hang tests at the Columbia Scientific Balloon Facility and then packing all the equipment to be shipped to New Zealand. In Wanaka, New Zealand I am the representative from the Mines Mechanical Team and it is my job to reconstruct all the structures needed for flight and preflight testing as well as provide mechanical support for smaller projects including assembling and testing solar panels, washing lenses and making a heater for the PDM. I have had the opportunity to be mentored by Doug Houi, a very experienced electrical and mechanical engineer for balloon projects. This incredible opportunity has enabled me to discover my passion of creating a design and have the capability to build the part myself and I could not be more thankful to Dr. Wiencke and Mr. Randy for this opportunity.

Left: The six wind belts. Right: Visual of the Coriolis Effect

Photos thanks to ( and (

The Winds Are Changing

Under the Flight Path tab there is a link to see a montage of daily high altitude wind maps. Ever so slowly you can see the winds develop over Antarctica and the winds are slowly changing direction. The explination of this phenomenon boils down to wind belts and the Coriolis effect. The globe is encircled by six major wind belts, three in each hemisphere. From pole to equator, they are known as the polar easterlies, the westerlies, and the trade winds. All six belts move north in the northern summer and south in the northern winter. The wind is caused by the uneven heating of the atmosphere. The equator has a higher density of solar radiation compared to the poles. The warmer air near the equator rises as the cooler air near the poles sink, giving wind a natural flow. The direction of the winds, the polar winds in particular, are effected by something called the Coriolis effect. Imagine an object starting at the North pole that is trying to move to the Equator in a straight line. Due to the Coriolis effect, this object would deflect to the right of the intended path due to the rotation of the Earth, counter-clockwise as viewed from the North Pole. The deflection is zero at the equator and reaches a maximum at the poles. The Coriolis Effect will make these winds change direction east to west as the belts are change from moving north in the northern summer to south in the northern winter. The winds at high altitudes are often faster and more consistent than that at ground level due to the lack of obsticles in the way.

Left: The top exoskeleton and SIP being lowered onto the exoskeleton uprights. Right: Wheeling the full assembly back into the hanger.

It's Alive!

On February 22nd, the exoskeleton was almost fully assembled. The top of the exoskeleton and SIP were lowered onto the uprights of the exoskeleton that has already been assembled. This means that all the mechanical structures built in Golden have been successfully built in New Zealand. The SIP is the white box looking structure hanging from the top crossbeams. It is built by the Colombia Scientific Balloon Facility and houses their hardware like power, flight computers, telemetry systems, and a way to communicate to different systems of the balloon. It is able to communicate to the flight terminatation system and the top of balloon to determinate the actual pressure of the spb during flight. It also controls the ballast system which allows the payload to drop weight during flight if necessary. There is over the horizon communication to Palestine so that it is controlled from there once the balloon is out of radio line of sight, which is in the first 5 or 6 hours of flight. The SIP also provides data path for the EUSO-SPB group to collect during flight. In addition there are multiple camera systems; some looks at the balloon since flying the balloon is an experiment in itself and others look at the horizon. There are at least 2 redundant systems in the SIP in order to ensure there is a backup system for everything. The next thing is to attach the boom, which holds the Iridium Pilot antennas which sends the data signal back to the ground in addition to multiple GPS antennas and cameras.

The launch vehicle with Rachel Gregg (Colorado School of Mines) in the basket where the crew chief will be during launch.

Labeled assembly for the mechanism that releases the payload during launch.

Top: Release Pin fully retracted. Bottom: Release Pin partially retracted.

Launching Vehicle Release Mechanism

For launching, there is a special vehicle that helps launch the payload and the balloon. This is a closer look at the mechanism used to release the payload and flight train. This is a not so simple task since about 3000 lbs needs to be transferred to the balloon and the whole thing released cleanly. First off, the flight train is defined as everything above the exoskeleton including the cables, parachute, balloon and termination unit. The flight train is attached to the six holes at the top of the white plate, called the truck plate. The payload includes the exoskeleton and the red box with the detector and lenses inside. The payload is attached to the lower 2 holes on the truck plate. The plate rests on a launch pin that has a slight upward angle to help the payload glide upward during launch as well as transfer the weight of the payload from the crane to the balloon. The pin is tapered so the balloon can pull the truck plate off the pin cleanly once the safety has been released There is a release pin assembly is a cable that attaches the truck plate to the release pin.

Before launch, the payload is lifted up by the crane on the launch vehicle. The crane is simultaneously holding the payload up and keeping the balloon down until the moment of launch. Right before launch, the launching vehicle is moving to match the surface wind so that the entire flight train is straight up and not blown at and angle due to wind. When it is time to launch, the crew chief located in the basket of the launch vehicle will pull on the release cable. This tug causes the release arm to be pulled backward. When the release arm is pulled, the release pin retracts which then releases the release pin assembly. At this point, truck plate, payload, and flight train are resting on the launch pin. The balloon and payload will then rise into the atmosphere. Once balloon is launched the crane must back up quickly to stay clear. The launching of the balloon is an impressive bit of physics and engineering at work. The entire weight is about 10,000 lbs including the flight train and the payload.

Left to Right: Francesco Cafagna (Bari, Italy), Lawrence Wiencke (Colorado), Guillaume Prevot (Paris, France), Pierre Barrillon (Orsay, France), Valentina Scotti (Naples, Italy), Abraham Neftali Diaz Damian (Toulouse, France), Johannes Eser (Colorado), Simone Bacholle (Colorado), Jorg Bayer (Tubingen, Germany), Giuseppe Osteria (Naples, Italy) in the hanger.

Old Friends, New Place

On February 15th, the science team on site increased to 14 people. Colleagues from Italy, Germany and France came and will stay for several weeks. They are experts ranging from the photon detection module, electronics, and flight software. They will each be working on testing the system after the long trip from Texas.

Left: Rachel (Colorado School of Mines), Doug Huie (University of Alabama Huntsville) and Johannes Eser (Colorado School of Mines) with the newly powder coated exoskeleton pieces. Right: Rachel Gregg (Colorado School of Mines) and Doug Huie finishing most of the exoskeleton assembly in record time.

Resurrecting the Exoskeleton

On February 14th, the exoskeleton was finished being powder coated. This is a paint that is put on the material as a powder which is then cured in extremely high heat. This kind of painting is typically more durable than conventional paint. It is scratch and crack resistant even in extremely low temperatures. The base of the exoskeleton was then assembled in record time by Mr. Doug and Ms. Rachel. Mounting the top of the exoskeleton requires a crane and will be done tomorrow. In addition every nut on the exoskeleton was replaced with lock nuts to ensure nothing should fall apart during flight. We were informed today today that the payload is actually too light and requires an extra 500 lbs attached to the exoskeleton in some way before launch. A solution is still being brainstormed but updates will soon follow.

Left: Simon Bacholle (Colorado School of Mines), Johannes Eser (Colorado School of Mines) working on the detector which is in a "black box". Right: Rachel Gregg (Colorado School of Mines) with the two fully assembled carts.

Wanaka Week 1

Week one by all accounts was a success. Mechanically the two carts needed for the detector and the exoskeleton are built and are being stored in a sea container to save space. The exoskeleton is being painted at a local powder coating place and should be done by the middle of next week. In addition, a dark box was built for the detector so that it can be safely worked on and tested in the next few weeks. As for the detector, it is able to be turned on at 1100V which is a very good sign! It is also able to take data when the cover is on. The next steps are to test it with an LED to see how it is detecting light and run a series of diagnostic tests to see what subsystems are working and what needs a little bit of work.

Left: Simon Bacholle, Johannes Eser, Rachel Gregg (Colorado School of Mines), and Doug Huie (University of Alabama Huntsville) in front of the SPB Sea Container. Middle and Right: Pictures of the inside of the containers. All the containers seem in their place and there is no obvious damage to any of the boxes.

Equipment Arrival in Wanaka

On February 4, 2017, the first wave of the EUSO-SPB team, Simon Bacholle (Colorado School of Mines), Johannes Eser (Colorado School of Mines), Rachel Gregg (Colorado School of Mines), and Doug Huie (University of Alabama Huntsville), arrived to Wanaka, New Zealand. The following day, the EUSO-SPB sea containers were inspected for the first time by the team. After a truck from CSBF to Port of Houston, a boat from Houston to Atlantic site of Panama Canal, back on a truck through Panama Canal, then loaded onto a boat on the Western Side of Panama Canal to Auckland NZ, another boat from Auckland NZ to Port Chalmers NZ, and finally a truck to Wanaka Airport, there is no obvious damage to any of the boxes which was a very good sign! The Red Box was taken out of the sea container so that the optical lenses could be inspected. They remained intact and appear in good condition. The next steps will be to strategically unpack the sea container. The space the EUSO-SPB group is able to use is about half of what it was in Palestine, Texas so the space needs to be used as efficiently as possible.

The SPB group in front of a successfully packed shipping container. Lawrence Wiencke (Colorado School of Mines), Johannes Eser (Colorado School of Mines), Simon Bacholle (Colorado School of Mines), and Rachel Gregg (Colorado School of Mines).

Packed and Shipped

On November 30, 2016, all the electronics and mechanical structures were disassembled and packed into 2 shipping containers. With a total of 36 labeled boxes and structures, the detector was officially on its way to New Zealand. It traveled to Houston through US customs, then was loaded on a boat to the Panama Canal. From there it traveled by train across the canal to another boat that will take it to New Zealand. The containers successfully arrived in Wanaka late January.

The EUSO-SPB instrument is planned for the Super Pressure Balloon Flight of 2017. The instrument was built, tested and hung from a crane in Palestine Texas. The SPB group above shows Simon Bacholle (Colorado School of Mines), Johannes Eser (Colorado School of Mines), Doug Huie (University of Alabama Huntsville), and Lawrence Wiencke (Colorado School of Mines).

Hang Test

The instrument had to travel to the Colombia Scientific Balloon Facility in Palestine, Texas to be assembled and undergo a hang test to ensure it was flight ready. The detector was sent to CSBF in two phases. The exoskeleton and carts were sent first so the CSBF personnel could start mounting their equipment. The detector was sent a few weeks later arriving on October 30th. Over a series of weeks, the detector was reassembled and tested.

On November 19th, the instrument underwent the hang test. Every mechanical structure of the apparatus was assembled and hung from a crane. It was then spun to ensure it could withstand the possible g Force's it would encounter during launch. The electronics were also tested to ensure the instrument worked as expected. The instrument passed and was cleared to head to Wanaka, New Zealand.

Left: Utah Campaign group on the first night. Right: GLS trailer 24 km from the detector.

Utah Campaign

On October 3rd, 2017 the instrument departed on a 1022 mile round trip journey to Delta, Utah. To ensure safe travel, an Air Ride trailer was bought, a system of a pilot car during transportation, and the field cart was designed by Mr. Austin Cummings to minimize the G Forces experienced by the detector to about 0.5 G Forces. Within 6 hours of arriving at the site, the detector was able to take data! It worked successfully in the field, a huge triumph for this experiment. While in Utah the 2 lens and 3 lens system was tested using the GLS laser system. Upon analyzing the data, it was discovered that the 2 lens system would be used for the flight since it had about twice the trigger efficiency. The 2 lens system was able to see lower energies and saw more of the laser tracks than the 3 lens system. Overall, this campaign was deemed a success in verifying the detector worked and which lens system would be best for the New Zealand campaign.

Top: Zachary Polonsky (Undegraduate), Randy Bachman (Mines Machine Shop Head), Rachel Gregg (Undergraduate), Johannes Eser(PhD Student), Austin Cummings (MS Student), Roy Young (MSFC) and Lawrence Wiencke (Mines PI) with the 1m diameter mirror that Roy and the Machine Shop Team helped mount and align. Bottom: The test stand as built with two lenses used in 2014 ready for testing.

Lens Testing

A collimated light source was designed and set up in the back of the Mines astroparticle high bay lab to measure the throughput and spot size of the EUSO-SPB lens system. Roy Young (Marshall Space Flight Center) arranged the loan of a 1 m diameter diffraction limited mirror from GSFC and helped mount it. Light from a fiber-coupled UV LED was placed at the focus of the mirror. UV LEDs of 340, 365, and 390 nm were used. The fiber bundle was 0.7 mm diameter and the system was aligned such that the collimated light incident on the mirror system was parallel to within 0.03 degrees. These specs ensured that distortions due to the collimator were small compared to the expected 3 mm diameter focus size of the optics to be tested. 3 lens configurations were measured: The 2 lens system flown in 2014, the 3 lens system fabricated in Japan for the 2017 Wanaka campaign, and the same system with the middle (diffractive) lens removed.

Analysis of the data collected found that the three lens system achieved two of its three design goals. The system focused light of the wavelengths tested at a common focal distance, and the spot size was small, on order of 3 mm. Unfortunately the throughput was low, about 14-18% on 1 cm^2. The system was also tested with the middle diffractive lens removed and the through put improved to 35% on 1 cm^2 at the expense of a large spot size and variation in focal distance.

Mechanical Team members Randy Bachman (Mines Machine Shop Head), Rachel Gregg (Undergraduate), Zachary Polonsky (Undergraduate) in various stages of the mechanical fabrication process. Also including Johannes Eser(PhD Student), Lawrence Wiencke (Mines PI), and Doug Huie (University of Alabama Huntsville Technician)

Mechanical Structures

The Mines group designed and fabricated 6 large mechanical subsystems for EUSO-SPB. These include an exoskeleton frame, battery mounting fixtures to hold 500 lbs of batteries inside the electronics compartment, gondola cart to hold the entire payload and roll it out for launch, a detector cart so that the detector can be assembled and tested independently, a field cart to hold the detector horizontally for shipping and the field tests and a support frame to hold a 700 lb collimator mirror assembly for lens testing. These structures were completed at the end of September.

The “exoskeleton” external frame was designed by Mines mechanical engineer Dr. William Finch to hold the cosmic ray detector and the various subsystems that are required to support a long duration balloon flight. These include CSBF Science Integration Package (SIP), antenna boom, ballast hoppers, solar panel “crinoline”, and batteries. Dr. Finch iterated his design with his counterpart at CSBF to ensure that the structure meet the CSBF strength and safety requirements. Three carts were also designed to handle the detector in vertical and horizontal orientations. The main cart and exoskeleton were designed so that the fully assembled instrument including antenna boom and antennas could clear the 13 ft 6 in hanger door at the Wanaka launch site. This will allow the fully assembled payload to be stored and tested in the Wanaka hanger prior roll-out for launch. The field cart was designed to minimize the G Forces experienced by the detector when it was being transported to Delta, Utah for field testing. The design was done by Mr. Austin Cummings.

The exoskeleton and 3 carts were fabricated in the Mines machine shop by machine shop head Randy Bachman, machinist Mike Mantz, and undergraduates Rachel Gregg and Zach Polonsky. Ms. Gregg welded much of the structure under the supervision of Mr. Bachman. Ms. Gregg prepared an assembly manual for the exoskeleton and carts as part of her undergraduate senior design project.

EUSO-SPB | Colorado School of Mines