Newsgroups: comp.robotics
Path: brunix!cat.cis.Brown.EDU!agate!ames!kronos.arc.nasa.gov!doctor
From: doctor@kronos.arc.nasa.gov (Terry Fong)
Subject: Dante II - Mt. Spurr Expedition Status (26-Jul-94)
Message-ID: <1994Jul31.081459.28279@ptolemy-ethernet.arc.nasa.gov>
Summary: status information on CMU/NASA volcano robot explorer
Keywords: Dante, teleoperations, volcano, Alaska
Sender: usenet@ptolemy-ethernet.arc.nasa.gov (usenet@ptolemy.arc.nasa.gov)
Nntp-Posting-Host: tardis.arc.nasa.gov
Organization: NASA Ames Intelligent Mechanisms Group
Date: Sun, 31 Jul 1994 08:14:59 GMT
Lines: 175

The following is a status update on the Dante II project. Dante II is
an eight-legged robot (developed by the CMU Robotics Institute with
sponsorship from NASA) which is currently descending into the active
crater of Mt. Spurr, an Alaskan volcano 80 miles west of Anchorage,
Alaska. The primary objective of the Dante II project is to develop and
evaluate new techniques and technologies which can be applied to space
and planetary exploration. 

Throughout the Mt. Spurr expedition, Dante II is being remotely
operated from a base station in Anchorage using control station
software developed at CMU and NASA Ames. Live video coverage is
periodically available via NASA Select. Full mission details including
current status, real-time images/video, and technical data is available
via a WorldWideWeb server provided by the NASA Ames Intelligent
Mechanisms Group. This site can be accessed on the Internet using
information browsers such as NCSA Mosaic and the URL:

	http://maas-neotek.arc.nasa.gov/dante

Questions regarding the Dante II project may be addressed to me via email 
(terry@ptolemy.arc.nasa.gov). Reponse time may be slow.

Terry Fong
NASA Ames Research Center

------------------------------------------------------------------------------

Daily Report (26-Jul-1994)

A break in the recent poor weather conditions finally allowed an
opportunity to move Dante from the dirt airstrip, where it has rested
since Saturday, the last two miles to the rim of the volcano crater.
Early this morning Tim Hegadorn, camped at the airstrip with Dante,
reported clear skies and good visibility all around the crater.
Within an hour, the ANG Blackhawk helicopter was departing from the
Fort Richardson airfield to the mountain.  After rendezvousing with
the camped guards at the dirt airstrip, the flight crews worked out a
final lift plan to move the power station, the robot, and the
satellite antenna up to the rim.

The pallet containing the electric supply generator and the generator
fuel tank, weighing a combined 4000 pounds, was the first load up the
mountain.  Carried as a sling load beneath the helicopter, the
generator skid was taken from the 3200 foot elevation airstrip and
placed precisely on the location marked by the reconnaissance team
early last week at the 7500 foot elevation of the crater peak.  Dante
was carried up next, also as an external sling load, and all of the
rim station electronics and equipment were carried inside the
helicopter.  During a slightly rougher-than-nominal set-down of the
Dante skid, two of the four bolts which hold the sensor arch in place
above the robot body were sheared and broken, and the sensor arch
metal work was bent when the arch contacted the underside of the
Blackhawk.  Following a visual inspection of the sensor arch, it was
found that the broken brackets and bolts (around which the arch
swivels during packing and deployment) could be repaired and replaced
on-site, and that the bend in the arch should not affect the
performance of any of the sensors.

As the project deployment team arrived at the crater via commercial
helicopter, the rim station equipment was being unloaded by the
Blackhawk crew.  Shortly thereafter, the Blackhawk departed back to
the Beluga airfield to refuel before returning for the final lift of
the satellite gear up to the crater.  Meanwhile, the deployment team
began the assembly of the rim station and associated equipment.  This
involved the cabling of the rim station electronics, completing the
anchor assembly for the robot's tether cable, anchoring and installing
the rim camera assembly, running the power cables the 250 feet from
the generator station to the rim station, and unlashing the robot from
the shipping pallet.

The elapsed time from the arrival of the first generator load at the
crater rim to this point was approximately two hours.  During this
period the weather conditions around the mountain had been worsening
(this volcano personifies the expression "if you don't like the
weather just wait an hour - it will change" - usually for the worse).
The cloud ceiling around the mountain had reestablished and was slowly
dropping in altitude, accompanied by an increasing rainfall.  An
evacuation of the crater site was ordered at approximately 1:00 pm, as
the weather conditions again became hazardous for flight.

The evacuation order occurred just as the Blackhawk was returning from
Beluga and getting ready hook up for the lift of the satellite
antenna.  Instead, the helicopter came straight to the rim site and
removed the last four people from the rim as the cloud cover descended
on the volcano.  In the time it took for the helicopters to descend
down to the dirt airstrip, the crater was completely enclosed in the
clouds and further attempts at access were impossible (a brief attempt
was made to lift the satellite antenna once the deployment team was
off loaded, but it was quickly aborted when it became obvious there
was no way in to the crater).  When the full team departed from the
airstrip the ceiling was down to 3500 feet and quickly descending as
the storm increased.  By the time the flight reached Beluga, 30 miles
away, the ceiling was down to 400 foot and the helicopters were flying
about at about 200 feet altitude.

Once the evacuation back to Beluga was complete, a review of the
hardware remaining for transport to the rim was conducted.  An
inspection of the feed horn for the satellite antenna had revealed
some potential damage to the structure.  To verify the condition of
the structure, and prevent any damage to the satellite transmitter,
the feed horn assembly was returned to Anchorage for testing in the
morning.  A repaired or replaced unit will be flown back to the crater
rim as soon as possible.

Weather permitting, the ANG Blackhawk will return to complete the
final lift of the satellite antenna tomorrow morning.  Once the feed
horn condition is verified, the deployment team will return to the
crater rim to complete the remaining installation tasks.  These tasks
primarily involve establishing the satellite communications and
testing the remote operations of the robot once the satellite link is
up.  From there, the robot will begin walking into the crater and the
team will egress the volcano.

At this point, it is probably worth a brief discussion to describe the
topography and appearance of the volcano crater for those who have not
seen the photographs (which are being posted on the WWW Mosaic page
http://maas- neotek.arc.nasa.gov/dante/dante.html).  The actual active
volcanic vent of Mt.  Spurr is located in Crater Peak, which is, as
described earlier by one team member after first viewing the volcano,
"a wart on the side of a larger mountain".  Crater Peak (7575 feet) is
located on the southern slope of Mt.  Spurr (11070 feet) and the
crater itself is shaped approximately like an 700- foot diameter open
funnel.  The north and west walls of the crater rise almost vertically
1000 feet from the crater floor, and are topped by a 100 foot thick
layer of glacial ice coming down from the upper slopes of the
mountain.  Due to a combination of the relative youth of these rock
faces (which were first exposed in the 1992 eruption of the volcano)
and material being pushed into the crater by the glacial flow, there
is almost constant rock fall from these walls.  Material ranging in
size from pebbles to 6-foot diameter boulders crash down from the
heights of the walls every minute or two.  Snow melt from the ice and
recent snow storms runs down the walls in thin waterfalls, much of
which is apparently turned to steam when it reaches the fumeroles at
the bottom of the crater.  As a result the crater is constantly alive
with sound, with the waterfalls and hissing steam forming a background
of white noise punctuated by loud crashes as free-falling boulders
slap the cliff faces.

The southern wall slopes up at angles between 30 to 70 degrees for
about 500 feet from the bottom of the crater.  The portion which would
rise above that level was blown out of the mountain by the 1992
eruption, leaving a relatively flat snow-covered plateau nearly 200
feet wide between the crater and the exterior mountainside.  Under the
snow, the plateau is covered in several feet of thick, gooey black mud
made from the volcanic ash of the eruption which sticks tenaciously to
everything.  As with the other faces of the crater, the exposed rock
of the south wall varies from a mottled gray to a deep red in color
(presumably due to a high iron content in some layers of the rock).

The east wall slopes up from the southern edge to blend in with the
north wall.  It is at the edge of the southern plateau between the
south and east walls that Dante has been placed to begin it's walk to
the crater floor.  "Crater floor" is a term that is applied to a
somewhat nebulous area at the bottom of the crater which includes the
talus piles built up from the rock fall off the north and west walls,
the exposed fumerole fields which are primarily along the south-
eastern wall, the boulder fields above the fumeroles, and an unknown
area in the center of the crater which is constantly hidden by the
steam and gases emitted from the fumeroles.

It is intended that the robot will walk down the south-eastern wall
and through the boulder fields at least as far as the upper edges of
the fumerole fields to gather readings from the gas sensors on board,
and to view behind a large rock bulge to investigate an area hidden
from view from the crater rim.  Depending on an examination of the
local terrain in the fumerole fields and the time required to traverse
the boulder field, further exploration into the fumerole field toward
the unknown area may be considered.

------------------------------------------------------------------------------
-- 
_______________________________________________________________________________
 "Every once in a while declare        Terry Fong <terry@ptolemy.arc.nasa.gov>
  peace. It confuses the hell out      NASA Ames, M/S 269-3, Moffett Field, CA
  of your enemies" -- Rule of Acq. #76      (415) 604-6063, (415) 604-6081 lab
