Mars Descent Imager (MARDI) on the Mars Polar Lander

Abstract

Abstract. The Mars Descent Imager, or MARDI, experiment on the Mars Polar Lander(MPL) consists of a camera characterized by small physical size and mass (---6 x 6 x 12 cm, including baffle; <500 gm), low power requirements (<2.5 W, including power supply losses), and high science performance (1000 x 1000 pixel, low noise). The intent of the investigation is to acquire nested images over a range of resolutions, from 8 m/pixel to better than 1 cm/pixel, during the roughly 2 min it takes the MPL to descend from 8 km to the surface under parachute and rocket-powered deceleration. Observational goals will include studies of (1) surface morphology (e.g., nature and distribution of landforms indicating past and present environmental processes); (2) local and regional geography (e.g., context for other lander instruments: precise location, detailed local relief); and (3) relationships to features seen in orbiter data. To accomplish these goals, MARDI will collect three types of images. Four small images (256 x 256 pixels) will be acquired on 0.5 s centers beginning 0.3 s before MPL's heatshield is jettisoned. Sixteen full-frame images (1024 x 1024, circularly edited) will be acquired on 5.3 s centers thereafter. Just after backshell jettison but prior to the start of powered descent, a "best final nonpowered descent image" will be acquired. Five seconds after the start of powered descent, the camera will begin acquiring images on 4 s centers. Storage for as many as ten 800 x 800 pixel images is available during terminal descent. A number of spacecraft factors are likely to impact the quality of MARDI images, including substantial motion blur resulting from large rates of attitude variation during parachute descent and substantial rocket-engineinduced vibration during powered descent. In addition, the mounting location of the camera places the exhaust plume of the hydrazine engines prominently in the field of view.

Mars 2007 Phoenix Scout mission Organic Free Blank: Method to distinguish Mars organics from terrestrial organics

“…Phoenix will land near 68°N latitude on polygonal terrain presumably created by ice layers that are expected to be a few centimeters under loose soil materials [ Arvidson et al , 2008; Mellon et al , 2008]. The payload of the stationary lander consists of the Thermal and Evolved Gas Analyzer (TEGA: W. V. Boynton et al, Phoenix thermal and evolved gas analyzer, manuscript in preparation, 2008), Microscopy, Electrochemistry, and Conductivity Analyzer (MECA, Hecht et al [2008]), Robotic Arm (RA, Bonitz et al [2008]), Robotic Arm Camera (RAC, Keller et al [2008]), Stereo Surface Imager (SSI: Lemmon et al, Phoenix Surface Stereo Imager investigation, manuscript in preparation, 2008), Meteorological Station (MET, Taylor et al [2008]), and Mars Descent Imager (MARDI, Malin et al [2001]).…”

The Mars Science Laboratory (MSL) Mast cameras and Descent imager: Investigation and instrument descriptions

“…Malin et al [] described the scientific rationale for acquisition of images during a descent to the Martian surface in the context of the Mars Polar Lander (MPL) Mars Descent Imager (MARDI) investigation. Given the importance of geologic context, Malin et al [] said, “among the most important questions to be asked about a spacecraft sitting on a planetary surface is ‘Where is it?’”…”

“…A slow fixed frame rate (as was required for the Mars Polar Lander MARDI [ Malin et al ., ]) results in a nesting scale ratio that varies during descent. For geologic and geomorphic observing, a 10:1 ratio is extremely difficult to use in comparisons from one image to the next but a ratio of 5:1 is much better.…”

“…Finally, a most important requirement—a lesson learned from the previous MARDI instruments developed for the Mars Polar Lander [ Malin et al ., ] and Phoenix Mars Scout lander—was for the operation of the instrument to be as decoupled, as much as possible, from the mission critical operation of computers controlling the spacecraft descent. Thus, the MARDI was designed to operate autonomously: after an initial turn‐on and warm‐up period, a single command would start the imaging sequence, and it would run to completion during the descent, and after landing terminate without further spacecraft interaction.…”

Simulating Martian boundary layer water ice clouds and the lidar measurements for the Phoenix mission

“…Phoenix will be the first scientific mission to study the history of water in all its phases using a suite of seven instruments. The payload comprises a Robotic Arm capable of gathering soil and ice samples, three cameras, the Mars Descent Imager [ Malin et al , 2001], the surface stereo imager [ Smith et al , 2001], and the Robotic arm camera; two analytical laboratory instruments, the Thermal and Evolved Gas Analyzer (TEGA) [ Boynton and Quinn , 2001] and the Microscopy, Electrochemistry and Conductivity Analyzer (MECA), and a Meteorological station (MET) consisting of a pressure sensor, three mast‐mounted temperature sensors, wind telltale, and an upward looking lidar (light detection and ranging) instrument.…”