Results from the Mars Phoenix Lander Robotic Arm experiment

Abstract

The Mars Phoenix Lander was equipped with a 2.4 m Robotic Arm (RA) with an Icy Soil Acquisition Device capable of excavating trenches in soil deposits, grooming hard icy soil surfaces with a scraper blade, and acquiring icy soil samples using a rasp tool. A camera capable of imaging the scoop interior and a thermal and electrical conductivity probe were also included on the RA. A dozen trench complexes were excavated at the northern plains landing site and 31 samples (including water‐ice‐bearing soils) were acquired for delivery to instruments on the Lander during the 152 sol mission. Deliveries included sprinkling material from several centimeters height to break up cloddy soils on impact with instrument portals. Excavations were done on the side of the Humpty Dumpty and the top of the Wonderland polygons, and in nearby troughs. Resistive forces encountered during backhoe operations show that soils above the 3–5 cm deep icy soil interfaces are stronger with increasing depth. Further, soils are similar in appearance and properties to the weakly cohesive crusty and cloddy soils imaged and excavated by the Viking Lander 2, which also landed on the northern plains. Adsorbed H2O is inferred to be responsible for the variable nature and cohesive strength of the soils. Backhoe blade chatter marks on excavated icy soil surfaces, combined with rasp motor currents, are consistent with laboratory experiments using grain‐supported icy soil deposits, as is the relatively rapid decrease in icy soil strength over time as the ice sublimated on Mars.

Seasonal H2O and CO2 ice cycles at the Mars Phoenix landing site: 1. Prelanding CRISM and HiRISE observations

“…The soil component utilized optical constants based on a Mauna Kea palagonite sample: a low‐temperature alteration product of fine‐grained basaltic ash [ Clancy et al , 1995]. Based on both orbital and ground observations, dehydrated palagonite mixed with nanophase iron oxides appears to be a good analog for the Phoenix site soils [ Arvidson et al , 2009; Heet et al , 2009]. For modeling, optical constants were used from Hansen [1997, 2005] for CO 2 ice, Warren [1984] for H 2 O ice, and solid densities of ρ = 1.562 g/cm 3 for solid CO 2 , ρ = 0.9167 g/cm 3 for solid H 2 O, and ρ = 2.700 g/cm 3 for palagonite were assumed.…”

“…The Phoenix primary and extended mission lasted most of the Martian northern summer (L s ∼80° to 145°) [ Smith et al , 2009; Arvidson et al , 2009]. However, our understanding of ice and dust cycles at the landing site is incomplete without analyses of ice evolution from L s ∼145° to L s ∼80° (late summer, fall, winter, and spring).…”

Concentrated perchlorate at the Mars Phoenix landing site: Evidence for thin film liquid water on Mars

“…2188N, 234.2508E, IAU 2000, including the 12 trenches that Phoenix excavated using its Robotic Arm (RA, Figure 1) [Arvidson et al, 2009]. With SSI, we examined soil features in each of the 12 trenches and compared them to undisturbed surface soils.…”

Tier-scalable reconnaissance: the future in autonomous C4ISR systems has arrived: progress towards an outdoor testbed

“…10) as seen by the Phoenix Mars lander. 35 The images below (Fig. 11) illustrate different steps in AGFA's processing cycle, and are automatically generated as benchmarks upon completion of the image smoothing, connected components labeling, and feature extraction steps, respectively.…”