Recovery Begins!

With SPIDER’s flight complete, the record of its observations resides in the payload’s data storage drives. SPIDER records data too quickly to transmit back via satellite, so the only way to get its valuable data back is by recovering those drives from the payload. The Antarctic Treaty also requires us to recover SPIDER’s hardware from the ice for environmental reasons.

All of this means: we need to send a team to SPIDER’s landing site. And yesterday we did!

Aerial Reconnaissance

Given SPIDER’s location, recovery flights to the SPIDER payload must be staged from South Pole Station. Canadian airline Ken Borek Air services such remote locations using two types of small aircraft: Twin Otter (DHC-6) and Basler (BT-67, a modified DC-3). These planes and their adventurous pilots can land in terrain and weather inaccessible to larger craft. They can carry both passengers and cargo, with quantities of each depending on distance and fuel allocation.

NSF and NASA/CSBF take advantage of a variety of satellite imagery to perform a first evaluation of the landing site. On January 10th the flight crew performed an initial reconnaissance flight to get eyes on the payload and terrain. The report back was excellent: SPIDER is largely intact, and the terrain looks favorable for landing and taxiing near the payload. Based upon this, LDB/CSBF put in a request for NSF to support a series of recovery flights; after a few days waiting for other operations to complete, we were given the go-ahead! Now the team gathers tools and waits for good weather…

The SPIDER payload at its landing site near Hercules Dome, as seen by the initial reconnaissance flight. The payload (mildly mangled) rests on its solar panel side, while the flight train and parachute extend to the lower right. Photo by Kelsey Kushneryk, Ken Borek Air.

Recovery in a Nutshell

SPIDER is too large to fit into the cargo holds of these aircraft, so the recovery team must cut up SPIDER’s carcass and bring it back in pieces. We on the science team are responsible for writing a procedure for this: what are the highest-priority items to recover, where to cut the big components, etc. The top-priority items are the data vaults: a set of solid-state storage and helium disk drives that hold multiple redundant copies of SPIDER’s data. Also high on the priority list are NASA SIP electronics box (located under the payload deck) and SPIDER’s major flight electronics, all accessible on the payload deck and on the belly of SPIDER’s cryostat. We labeled these top-priority items in black marker before launch, even marking up the deck to show the easiest places to cut.

With the SPIDER and CSBF teams sent off-continent so early this year, recovery work stretches the few remaining people extremely thin. LDB team members Scott Battaion (CSBF) and Rose McAdoo (ASC) went to Pole to support recovery, along with SPIDER team member Sasha Rahlin (already there for work on the South Pole Telescope). Along with the flight crew, this group must make several trips to the payload for long hours of work at wind chills of -60F. Upon return to Pole, they will pack up the high-priority cargo for return to North America. Depending on how many flights the weather permits this season, they may also have to judge when to stop the recovery process, and prep the remainder of the payload for the long winter.

First Recovery Flight

After a few days of poor weather, the team made their first trip out to the payload on January 21st. After a hard day’s work, they managed to return all of SPIDER’s high-priority data and electronics to the South Pole – a huge success!

Recovery in progress! Photo by Scott Battaion.
The first day’s plunder. Photo by Scott Battaion.

SPIDER’s data now begins a long journey back to North America. Along the way we make copies, both to secure against damage or loss in shipping, and to distribute among the various collaborating institutions. One copy of the data drives will be made at Pole. The drives will then head to McMurdo and on to Christchurch, where a SPIDER team member will make additional copies for distribution back home. Then the real fun begins, and we see what the data can tell us about our universe.

SPIDER-2 Returns to Earth

SPIDER is on the ground! The flight was terminated a little over an hour ago, with touchdown circa 0418 UTC on 07 Jan 2023 (1018 CST on 06 Jan), just over 16 days after its launch. SPIDER took a somewhat meandering path around the continent, as the usual orderly circumpolar pattern of stratospheric winds just never quite got established this season. In consultation between CSBF, NSF, and the science team, the decision was made to terminate over favorable terrain for recovery. The payload has come to rest near the Hercules Dome field camp, about 430km from the South Pole.

SPIDER-2’s complete flight path, from McMurdo at lower right to Hercules Dome near center. Image courtesy of Columbia Scientific Balloon Facility (link)

CSBF and ASC personnel have already arrived at South Pole Station to prepare for SPIDER’s recovery. We anticipate recovering our data storage in the coming weeks, with hardware recovery in a future season. The whole team looks forward to seeing what SPIDER’s new data hold in store.

Farewell to SPIDER

And I want to bid a very fond farewell to SPIDER itself, the product of many years of hard work, creativity, and care by so many excellent teammates. It’s hard for me to imagine, but it’s been just about 14 years since I arrived at Caltech as a newly-minted Ph.D., looking for an exciting new project to work on. The late Andrew Lange, along with Marcus Runyan, Bill Jones, and others, convinced me to join the effort to build a crazy new instrument to hunt evidence of primordial gravitational waves from a balloon. And then I met a fantastic (and growing) team of scientists who I am happy to call both colleagues and friends.

The two-flight plan has taken a little longer than we might have guessed. Through two homes and major career changes, from new postdoc through tenure. Through three heartbreaking canceled seasons, first from a government shutdown and later from a multi-year pandemic. As the newly-arrived students of yesteryear matured into senior scientists in their own right, making their own impacts in academia and industry. And through the entire lives of my two children, now 7 and 10, who have always known that their dad worked on some kind of balloon-thing called (for some inexplicable reason) “spider”.

And now SPIDER has done its job, made its journeys, and gathered what news it can about our universe. Its disk drives wait in the snow for retrieval and return to the northern hemisphere. There our team will begin the hard work of translating SPIDER’s record from its journey into a view of the universe’s first moments. All that lies in the future. But tonight, a toast to our good ship, and to the team that built her.

SPIDER and most of the 2022 ice team, with Mt. Erebus in the background. Taken in the early hours of December 22nd, not long before SPIDER headed to the launch pad. Photo by Scott Battaion.