McMurdo Day 58: Hooper's Shoulder and Nausea Knob

Another trip to Erebus! We serviced two more PASSCAL sites on Wednesday.

We showed up at the helicopter hangar at 7:30am, fully prepared for a weather cancellation. Good weather days, with wind speeds safe for the helicopters to fly in, are few and far between on Erebus. To my surprise, it was another glorious weather day! And the group after us on the helo schedule cancelled, so we had 7 hours with the helicopter -- meaning we could service two sites instead of just Hooper's Shoulder, as originally planned.

Flying over Castle Rock.

Helicopter selfie!

Approaching Erebus. The pilot (right) had an oxygen tank that he turned on when we got above 10000ft.

We landed at our site at Hooper's Shoulder. This is a "low" elevation site, at only 7500ft. It's on a sloping snow field on the side of Erebus, and I was worried the whole time that our boxes of equipment would just start sliding down 7500ft straight into the sea.

Looking down the snow slope from Hooper's Shoulder. That's Cape Bird off to the right.

There aren't many great places for the helicopter to land there. The pilot (Ryan) found a mostly flat spot in the rock. He landed, turned the helicopter off, and stepped out. And then immediately jumped back in because the right skid was hovering in midair.

Ryan turned the helo back on and scooted us forward a few feet. When Avi and I were getting out, he told us to jump back in if the helo started to tip backwards. So that was just a little nerve-wracking.

A-star helicopter parked mostly level.

There's only one station at Hooper's Shoulder; unlike Lower Erebus Hut, which has both broadband and strong motion sensors, this site just has broadband. We noticed immediately a major problem with the site: the enclosure was tipped 45° sideways. The wind had scoured out snow from behind and underneath the enclosure, causing it to fall over.

Sideways enclosure :(

When we opened the box, all eight of the 75-lb batteries had slid over, crushing the other equipment (datalogger, charge controller, and modem). As the batteries slid, they broke several connectors on the interior cables. Avi and I spent some time replacing all the cabling, moving the batteries out and back in, and shoveling snow to level the box.

Sideways enclosure again. You can see how steep the snow slope is.

This site had been offline since December 2020, and we quickly deduced why. The antenna cable was, once again, unplugged from the Iridum antenna. Clearly we need to come up with a better solution -- the wind has slowly loosened the cables at 2 of the sites we've visited! We ziptied (excessively) the cable to the solar mount in the hopes that it would be less likely to disconnect if it were held still.

The site, now all fixed! Confirmed with a call on the satellite phone.

There were also some funky problems with the charge controller at this site -- the charge controller helps manage charging the batteries from the solar panels. It also has fun cool features like a Low Voltage Disconnect (LVD), which stops powering the site if the batteries drop below 11.5V. We have this feature because a) it can damage the equipment if it's powered at too low of a voltage, and b) it can permanently damage the batteries if they are drained below 11V, and we want to avoid lugging 600lbs of batteries back up here if we can help it.

Anyway.. the charge controller was reporting an incorrect voltage for the batteries (which we measured separately with a multimeter), so we replaced it with a new one. We'll take the broken one back to PASSCAL to diagnose what's wrong with it.

PASSCAL team high-five for another site serviced!!

Once we serviced the site and confirmed that it was transmitting back to PASSCAL, we had some time for pictures. The chaplain in McMurdo is also from New Mexico, and he wanted Avi and I to take a picture for him with his New Mexico flag on Erebus.

New Mexico claims Hooper's Shoulder.

Necessary geologist picture of the rocks, with glove to scale. You can see some huge anorthoclase feldspar crystals!

We loaded back in the helicopter and prepared to fly up to our next site on Nausea Knob. On the flight over, we did a recce flyover of Macintosh Ridge, where we will be installing a new seismic station next season. This was super helpful for me and Avi, because we now have a better idea of the site and how our equipment will need to be laid out.

Picture from a flyover of Macintosh Ridge. There is a GPS site there already.

We continued on to Nausea Knob (called such because it is the highest altitude site at 11500ft, where you are certainly likely to feel nauseous from the elevation). Right before we landed, the pilot did a "power check" to make sure the helicopter had enough power to hover in place, so we'd be sure to be able to take off again. However, the winds were too strong, and the helicopter too heavy, so we immediately began sinking.

Ryan turned us around and landed down at Lower Erebus Hut, and we started chucking equipment out of the helicopter so it would be light enough to fly back up. We threw out most of science equipment, and even the survival bags (Ryan told us "we'll be close enough to hike if we need to"). When we took back off this time, the helicopter was light enough to hover and safely land at Nausea Knob.

Me and the helicopter.

It had been a beautiful, clear summer day, at a balmy -12°C (10.4°F) on Hooper's Shoulder. No such luck at Nausea Knob. Still clear and sunny, but -22°C (-9.4°F) with 14 knot (16mph) winds. According to the NWS Wind Chill chart, that put us at a wind chill of about -32°F. 

It felt so cold. So, so cold.

Here I am looking miserably cold at the Nausea Knob site.

Thankfully, this station was working as expected and we didn't have much work to do. We swapped the baler (that giant orange 7lb harddrive), cleared the rime ice off the antennae, briefly checked all systems, and got the heck out of there.

Rime ice on the antennae and solar panel junction box.

Solar panel with beautiful Erebus, steaming away.

The enclosure. We used the laptop to service the equipment and my hands got so cold.

I was way too cold to take pictures, so all of the Nausea Knob pictures I've included here were taken by Avi. I have certainly felt uncomfortable at other sites in Antarctica, but at Nausea Knob, I passed over the line from just uncomfortable to really not having a good time. I started shivering and had to go sit in the helicopter to warm up while Avi and Ryan wandered around a little bit.

Looking north into the Ross Sea.

Finally, we climbed back in the helicopter and flew back down to Lower Erebus Hut to retrieve all of our equipment. Then we were on our way back to McMurdo! It was an exhausting day, but I am so happy we've serviced 3/4 of our sites on Erebus!

A line of ice fumaroles pointing up to Erebus' summit.

Look at all that open water! The sea ice is really breaking up.