This post is very late: my site had server issues that have finally been resolved. I post this just before heading out to join much of the rest of the team already in Antarctica! After successfully cooling down and testing Spider’s detectors, the final thing to do was our compatibility test. For this, the payload gets completely assembled and we roll outside to test that the NASA satellite communication (and everything else) works properly. This requirement is the primary reason that we go to Palestine in advance of Antarctic flights. This was the end of my stay in Texas, since I had to leave early to attend a conference. Though I missed the first couple days to stay for compatibility. Oops, sorry, I only missed packing. We were also joined by a few Princeton undergrads: Zakiya, Andi, and Shannon. Extra hands were very welcome in the final crunch, and hopefully they enjoyed a bit of science before the packing. Lots of balloon science is just packing and unpacking anyway. […]
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We’ve had a very busy couple of weeks since the last update. First, we performed the lift operation to marry the pre-cooled cryostat with her supportive gondola. This made the Spider payload functionally almost complete, except for the sun shields and solar panels. After the lift/marriage we could start filling Lloro with liquid helium so that she could cool our detectors down to the very cold temperatures at which they operate. For the cryo nerds, we also then use a capillary-filled pumped helium-4 bath to get below 2 K and closed-cycle helium-3 adsorption refrigerators to get down to 0.3 K (around -273 C). Once we had cold detectors, our goal was to do all the science we could with the limited time and liquid helium that we had available, by conducting a battery of different tests on Spider’s six telescopes. We split into two shifts to manage Lloro’s needs at all times of day, and to efficiently get lots of testing done. Detector experts Jeff and Sasha joined us for this time. Though we also lost Sho to exam studying. […]
Last week Spider started to come together as a complete experiment, rather than a collection of parts. The gondola frame was completed, and most of its "outer frame" electronics were installed. Then it was moved over into the west highbay with out cryostat Llorothaag, in preparation for them coming together. NASA’s electronics were also installed, which will eventually allow us to communicate with the ground. In the last of cryogenics, we also started pre-cooling Lloro with liquid nitrogen. Our limited times with Susan and with Sho came to an end, but it was great to have them here. […]
Yesterday was a double-occasion: Suren’s birthday, and the first time that we filled the cryostat with liquid nitrogen. To celebrate, and to appease the temperamental cryogenic gods, we performed the ritual sacrifice of a unicorn (pinata). The liquid nitrogen is used to pre-cool everything before we switch to the even colder liquid helium. In the week leading up to this point, we had to test for leaks in our vacuum vessel (and had no leaks!), pump it out to thermally isolate the different temperature stages, and test all of our cryogenic gear. Outside of cryostat progress, we also completed the second run of the Bemco thermal/vacuum test chamber, built the gondola frame that will carry everything in flight, and started testing some of our calibration equipment. […]
With the lab set up, our first big task was to get our cryostat Llorothaag (aka Lloro) ready to do science. She both holds Spider’s six telescope inserts, and allows the detectors to reach the extremely cold temperature they need to operate with high sensitivity. Lloro has layers nested within that get progressively colder: starting with the vacuum vessel at ambient temperature that allows the air to be removed inside like a vacuum flask; then two layers of vapour cooled shields (VCS) before reaching the main liquid helium tank and the smaller superfluid helium tank, and finally the closed cycle helium-3 adsorption fridges. To get ready to operate, these layers need to be disassembled, before the science instruments can be installed inside, and then all closed again. We also had a trickle of new people arriving throughout the week. First Elle and Simon arrived, followed Johanna and Jared, then Bill, and finally Jason and Sho. We also lost Sherry, who left to start her new job and be reuinited with her puppy. Bye Sherry, we’ll miss you! […]
Spider-2 finally has a chance to go to the field! After a short notice decision that we’d have a chance to fly this year, we jumped into action spending a frantic month packing. I include a few photos from this time in Princeton, mainly of our cryostat (named Llorothaag, or Lloro for short) going into her box. First we go to Palestine, TX, and the Columbia Scientific Balloon Facility. There we will reassemble and test Spider, and integrate with the NASA electronics. Lloro’s trick arrived on May 27, the first wave of people arrived on May 31, and I came with another wave the day after. Much of the time so far has been spent unpacking and organizing our work area, but we’re also starting on some work and assembly that will take a while: preparing Spider’s six telescope inserts to do science, and preparing to test all of the ambient temperare electronics in the Bemco. The Bemco is a big thermal/vacuum test chamber used to simulate the environment of a balloon payload in the stratosphere. […]