D-Chall's Excellent Adventure: End of Phase I

Mermaid Sapphire is back at Apra Harbor, Guam, marking the end of the Phase I voyages of D-Chall, as backed by the National Geographic Society and Rolex. (D-Chall is my abbreviation for Deepsea Challenger; I'm tired of typing the full name and if J Lo can thrive under an abbreviation, the sub can too.) 

Here's a newly released photo, taken a month ago by one of the unmanned craft:

This photo is of interest because it's one of the few photos of the lower pod that shows the science door as swung open by its hydraulic actuator. Here's a closeup, including what look to me like sample containers:

For the participants, Phase I must have been an exciting combination of sea trials, actual science, and lessons learned. The expedition journals don't reveal any close shaves, but do suggest that the missions below 20K feet were pretty hard on some equipment, particularly the battery buses and hydraulic manifolds. 
There was a glitch in ballasting on the March 4 dive that must have given James Cameron an unwanted thrill, though it never involved the critical hardware, the ascent-weight release system. 

The good news is that there was plenty of redundancy and the team managed the inevitable problems as they arose. And it was complex! Take a look at this closeup from an NGS photo of the lower pod manifold area.

Geeky readers will note that some of the lines are labeled:

Back to the big picture. 

While Phase I was a qualified success, the press release is guarded about the scale of plans for Phase II, given the operational costs (like a million dollars a month, just for the vessels; team personnel, mission support, and expendables would be extra). The role of unmanned deep-divers Mike and Andrew will be an interesting question. As I surmised in this March 28 post, the science team on Barakuda kept the twins busy following the deep-dive media blitz. That included a trip to the Sirena Deep.

The incremental approach when deploying D-Chall (progressively nudging the envelope, followed by close analysis of each mission, repairs, and retraining) is the kind of thing test pilots do. It pays handsome returns in safety dividends. 

In Inviting Disaster I wrote about how seemingly dangerous work can be rendered survivable by a thoughtful, incremental approach. One WWII-era example was Royal Aircraft Establishment pilots who tested the efficacy of barrage-balloon cables by ramming them with their airplanes.

The Deepsea Challenge expedition modified its plans at several points. Apparently the original schedule did not include deep trials between Australia and the Challenger Deep, but Papua, New Guinea, was on the way, so the team decided to stop there for trials to 27K feet, at the cost of some sea time over the Deep. Probably a good thing ... 

Here's my second draft of D-Chall's dives and dates. The website says 13 trials or dives have been made to date, so I may be missing one or have it in the wrong place. Note: the last item in the table was a lander dive, not a D-Chall plunge. I'd imagine that Phase I involved many lander dives that are not on this list.

Date (Local)	Label	Location	Max depth (feet)	Notes
01/26/12	First submersion – no pilot	Dock at Garden Island Naval Depot, Sydney Harbor	< 5	Checks for buoyancy and water tightness
01/31/12	First piloted submersion	Dock at Garden Island Naval Depot, Sydney Harbor	< 5	First time JC piloted sub
02/01/12	Piloted open-ocean test	Jervis Bay, S of Sydney	To ocean floor	Reduced use of heat-emitting equipment, to lower sphere temp
02/21/12	First attempt, test dive to 3K feet	Jacquinot Bay, 3 mi offshore of Papua, New Guinea	0	Sub launched with JC, but aborted after 1 hr. Stayed on surface
02/22/12	Second attempt, test dive to 3K feet	Jacquinot Bay	0	Scrubbed due to camera-control problems
02/23/12	Test dive to 3K feet	Jacquinot Bay	3,250	Successful dive, photography, moved horiz at 3 kt, and rendezvous with lander Mike and yellow ROV operated from above
02/27/12	Attempted test dive to 12K	Jacquinot Bay	0	Scrubbed
02/28/12	Test dive to 12K	Jacquinot Bay	12,000	Successful rendezvous with landers Mike and Andrew, maneuvered 5 km horiz with guidance from ship
03/04/12	First Dive, New Britain Trench	New Britain Trench	23,818	On way to NB Trench bottom, tried to stop 5 kt descent with large dumps of trim shot, then ascended slowly; then dropped ascent wts
03/07/12	Second Dive, New Britain Trench	New Britain Trench	26,791	Successful dive to trench bottom for photography – maneuvered 1.5 km horiz, 300m vert
03/21/12	“Unpiloted” test dive to Challenger Deep	Not specified	“nearly seven miles”	Pressure “almost 8 tons per square inch”
03/25/12	First solo trip to deepest point	Challenger Deep (vicinity of 11.3632, 142.5770)	35,756	Successful dive – first solo dive to bottom of hadal zone photography; part of one core sample brought up; surfaced at local noon
04/01/12	First Dive, Ulithi Atoll	West of Ulithi Atoll, in Zowariyau Passage	> 3,000 ft	RA's first dive; goal to rendez with Mike and ROV quasar – result ?; Photography successful
04/02/12	Possibly a second piloted dive off Ulithi	Ulithi Atoll ?	- ? -
04/03/12	Dive by lander from Barakuda	Sirena Deep, Mariana Trench Marine Natl Mon	>35,000 ft	Sampling and photography