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SPIDER is a long duration balloon-borne experiment designed to measure the polarization of the cosmic microwave background with unparalleled instantaneous sensitivity. Novel detector architecture allows for illumination of approximately 2500 detectors through an effective collecting area of roughly 0.5 m2. SPIDER mapped the polarization of the CMB over a tenth of the sky during a 17-day Antarctic flight that took place in January 2015. A subsequent flight of the SPIDER payload is planned for the 2019–2020 Antarctic season.

The following video shows the launc of the payload as well as some footage obtained from on-board cameras during the first few hours of flight. If you look closely, you can see Ross Island, McMurdo statio, and Mt Erebus.



You can find some more SPIDER-related videos here. Also, if you are curious do check out some of the other content on SPIDER available online. For example, the Princeton blog page, our Flickr account, and list of public coverage on our wiki page.

SPIDER had a successful flight with an instantaneous sensitivity in line with theoretically informed estimates (Fraisse 2011). During the first flight, SPIDER generated 1.56 TB of raw detector timelines in the form of approximately 400 billion detector timeline samples. This is roughly twice that of the entire Planck data set.

SPIDER's first flight deployed about 700 and 1300 detectors at 94 and 150 GHz, respectively. The integrated sensitivity of the 17 day flight is comparable to that of BICEP2, but spread over almost ten times more sky. The estimated B-mode sensitivity from the first flight data corresponds to a detection of r = 0.03 at a 95% confidence level, without accounting for foreground contamination.

The large sky coverage, raw sensitivity, and reduced filtering requirement compared to ground-based experiments set this instrument apart from all other funded probes of cosmic inflation. Figure 2 shows the predicted statistical sensitivity curves of SPIDER together with current measurements and upper limits from CMB polarization experiments.