Mars Curiosity Rover Scientific Instruments Explained in Detail - MSL Science Payload (SUBTITLES)

Uploaded by revoeciov on 08.05.2012

The new Mars Rover Curiosity is about the size of a small SUV and brings to Mars a collection
of 10 scientific instruments plus an array of other instruments, tools, electronics,
communications, and power supply. The arm is 7í long with jointsÖ kind of
like a shoulder, elbow, and wrist. At the end of the arm is a turret that can hold various
tools like a percussion hammer, scoop, and brush device, and can spin them through a
360 degree range. It is 10í long and 9í wide. It is 2X as
long and 5X as heavy as Spirit and Opportunity. It is too heavy and big to land with airbags
like Spirit and Opportunity did in 2004. Instead it lands using descent thrusters and guided
by ground sensing radar. The Mars Descent Imager (MARDI) is a fixed-focus
color camera, fixed-body-mounted to the front port side of Curiosity, pointing down, and
even with the roverís chassis. MARDI will start recording high-resolution
video about 2 minutes before landing on Mars. Initially the camera will glimpse the heat
shield falling away from beneath the rover, revealing the Martian terrain below. The first
scenes will cover the ground several kilometers, or a few miles across. The image will spin,
then shake as the roverís parachute, then its rocket-powered backpack, slow the roverís
descent. The left-front wheel will pop into view when Curiosity extends its mobility and
landing gear. Knowing the location of loose debris, boulders,
cliffs, and other features will be important in planning the routes Curiosity will take
after landing on Mars. MARDI will take color video, a first for Mars
exploration, during the roverís descent toward the surface. As soon as the rover releases
its heat shield, the Mars Descent Imager will begin producing a 5-frames per second video
stream of high-resolution, overhead views of the landing site. It will continue acquiring
images until the rover lands, at which it will turn off.
The video information and other data wonít be available immediately however, as data
will be sent to Earth via relay by 1 or 2 Mars orbitersÖ. so the daily data volume
will be limited by the amount of time the orbiters are overhead each day.
MEDLI (or Mars Science Laboratory Entry, Descent and Landing Instrumentation) isnít one of
Curiosityís 10 scientific instruments but is an integral part of the science of the
Curiosity Rover. It is built into the heat shield that protects the rover on its descent
through the Martian atmosphere. MEDLI will collect engineering data during
the spacecraftís last 8 minutes of high-speed-extremely hot entry into the Martian atmosphere. It
is predicted that heat levels will be about 3X higher than those of the Space Shuttle
when it entered Earthís atmosphere. This information will tell engineers how well the
heat shield performed. MEDLI is actually composed of two parts: MISP
(MEDLI Integrated Sensor Plugs) and MEADS (Mars Entry Atmospheric Data System). When
the spacecraft faces extreme heat during entry into the Martian atmosphere, MISP will measure
how hot it gets at different depths in the spacecraftís heat-shield material. MEADS
will measure the atmospheric pressure on the heat shield during entry and descent. The
MEADS pressure sensors are arranged in a special cross pattern in the heat shield. This cross
pattern will also allow engineers to determine the spacecraftís orientation.
Researchers can use MEDLI data to improve designs for future Mars-bound spacecraft.
A lot of people wonder why the Curiosity Rover doesnít have any solar panels like the Mars
Rovers Spirit and Opportunity. Spirit and Opportunity often found themselves
short on power as dust settled on the solar panels. This was especially a problem during
the short days of winter. NASA needed a good strong reliable source of power to keep the
Curiosity Rover going for 2 years on Mars. Curiosity is 2X bigger, 5X heavier and has
15X the weight of scientific equipment as Spirit and Opportunity. Samples collected
while roving over the Martian surface are delivered to some very sophisticated and power
hungry analytical laboratories on board. Thatís where the MMRTG comes in. The Multi-Mission
Radioisotope Thermoelectric Generator is a power source that has been used for years
to power spacecraft that have gone to the outer planets ñ and even the Apollo missions
used it on the moon. The MMRTG is located on the back of the rover.
The generator contains a specially produced form of Plutonium Dioxide. The natural decay
of this isotope gives off heat which thermocouples turn into electricity. The generator provides
both electrical power and heat to the Rover. About 100 watts of electrical power is used
to continuously charge the Rovers batteries. Also heat can be pumped off of the generator
using pipes to keep the Roverís insides warm - including the scientific instruments. Curiosityís
generator will keep its batteries charged year- round in all sorts of conditions.
The Rover Environmental Monitoring Station or REMS (provided by the Spanish Government)
is a tool which sits partway up Curiosityís mast and is a Martian weather station. REMS
will measure and provide daily and seasonal reports on atmospheric pressure, humidity,
ultraviolet radiation at the Martian surface, wind speed and direction, air temperature,
and ground temperature around the rover. Two small booms on the rover mast will record
wind speed to characterize air flow near the Martian surface from breezes, dust devils,
and dust storms. A sensor inside the roverís electronic box will be exposed to the atmosphere
through a small opening and will measure changes in air pressure. A suite of infrared sensors
on one of the booms (boom 1) will measure the intensity of infrared radiation emitted
by the ground, which will provide an estimate of ground temperature. A sensor on the other
boom (boom 2) will track atmospheric humidity. Both booms will carry sensors for measuring
air temperature. An array of detectors on the rover deck that are sensitive to specific
frequencies of sunlight will measure ultraviolet radiation at the Martian surface and correlate
it with other changes in the environment. All of this information will be integrated
into daily and seasonal reports, allowing scientists to get a detailed look at the Martian
environment. Mounted high on Curiosityís mast, extending
upward from the Curiosity roverís body, is the Mast Camera (MASTCAM). MASTCAM will use
a side-by-side pair of cameras for examining terrain around the rover. MASTCAM is actually
comprised of 2 cameras: MASTCAM 100 ñ a 100 millimeter focal length camera offering telephoto
capability and MASTCAM 34, offering a wider-angle view. Each can provide color images and high-definition
video, and they can be combined for stereo views. They are both scientific and natural
color imaging systems. MASTCAM 100, the telephoto camera is referred
to as the ìright eyeî because of its position on the mastÖÖand MASTCAM 34 is referred
to as the ìleft eyeî. The ìright eyeî MASTCAM-100 looks through
a telephoto lens, revealing details near or far with about three-fold better resolution
than any previous landscape-viewing camera on the surface of Mars. The ìleft-eyeî provides
broader context through a medium-angle lens. MASTCAM-100 provides enough resolution to
distinguish a basketball from a football at a distance of seven football fields.
MASTCAM is used to study the Martian landscape, rocks, and soils, and to support the driving
and sampling operations of the rover.
The Chemistry and Camera Instrument or ChemCam is probably the coolest instrument aboard
the rover. It fires pulses of a laser at a target such as a rock. Energy from the laser
excites a pinhead-size spot on the target into glowing, ionized gas called plasma. Spectrometers
in the instrument analyze the spectrum of light emitted by the plasma to identify chemical
elements in the target. Different elements glow in different wavelengths, or colors.
The technique is called ìlaser-induced breakdown spectroscopy.î
There are 2 parts to the ChemCam Instrument. First is the body unit, which goes inside
the body of the rover and contains 3 spectrographs for analyzing the ionized gas. The other is
located on the mast and contains the laser, imager and telescope. An optical fiber from
the mast unit delivers the telescopeís observations to the body unit.
This image shows a ball of luminous plasma erupting from the surface of an iron pyrite
crystal in the testing chamber. The laser beam itself is invisible.
The instrumentís camera is called the remote microimager. It photographed this dollar bill
from 10 feet away. The instrument can fire a laser at Martian
rocks up to 30 feet away and analyze the composition of the vaporized bits. ChemCam enables Curiosity
to study rocks that are out of the reach of its flexible robotic arm.
Provided by the Russian Federal Space Agency, the Dynamic Albedo of Neutrons, DAN, will
check for water bearing minerals in the ground beneath the Rover.
DAN, located near the back of Curiosityís main body, has 2 major components: a pulsing
neutron generator, on the starboard side of the Rover, and the detector and electronic
module on the port side. It will help the rover search for ice and water-logged minerals
beneath the Martian surface. The instrument will fire beams of neutrons at the groundÖ
then note the speed at which these particles travel when they bounce back. Hydrogen atoms
tend to slow neutrons down, so an abundance of slower neutrons would signal underground
water or ice. (DAN) should be able to map out water concentrations
as low as 0.1 percent at depths up to 6 feet.
The Radiation Assessment Detector (RAD) is one of the first instruments sent to Mars
specifically to prepare for future human exploration. A joint collaboration with Germanyís National
Aerospace Research Center, it is the size of a small toaster. RAD measures and identifies
all high-energy radiation on the Martian surface such as protons, energetic ions of various
elements, neutrons, and gamma rays. The instrumentís telescope faces upward from a position near
the front left corner of Curiosityís deck. 2 kinds of detectors in the instrument monitor
charged particles. A 3rd type detects neutral particles. This includes direct radiation
from space, the sun, from distant supernovas, other natural sources, and also secondary
radiation. A stack of paper-thin, silicon detectors and
a small block of cesium iodide measure high-energy charged particles coming through the Martian
atmosphere. To help prepare for future human exploration,
RAD collects data that will allow scientists to determine any harmful effect radiation
would have on astronauts on a mission to Mars.
The Sample Analysis at Mars instrument (SAM) is the largest of Curiosityís 10 scientific
instruments. It is actually a suite of separate instruments about the size of a microwave
oven. It takes up more than half of the science payload aboard Curiosity and features chemical
equipment found in many scientific laboratories on Earth. It consists of a mass spectrometer,
a gas chromatograph and a laser spectrometer. SAM is an automated mobile laboratory that
is carried across Mars by the rover. These instruments search for methane and carbon-containing
compounds, the building blocks of life as we know it. They also look for other elements
associated with life on Earth, such as hydrogen, oxygen and nitrogen. SAM will help assess
whether Mars ever was, or is still today an environment capable of supporting microbial
life. The SAM instruments are located inside the
body of the rover. The roverís robotic arm will drop samples into SAM via inlet tubes
on top of roverís deck. Some samples will come from deep inside rocks, bored out by
a drill situated at the end of the robotic arm or scooped up from soil. Samples will
be delivered to 2 separate ovens which will heat the samples to about 1,800 degrees F.
SAM will also take atmospheric samples through separate ports on the side of the rover.
The Chemistry and Mineralogy instrument, or CheMin will identify and measure the abundance
of various minerals on Mars. This will help scientists better understand past environmental
conditions on the Red Planet. Like SAM, CheMin has an inlet on Curiosityís
deck to accept samples delivered by the roverís robotic arm. Curiosity will drill into rocks,
collect the resulting fine powder and deliver it to a sample holder. It will also use the
scoop for collecting soil. Unlike SAM, CheMin will then direct a beam of X-rays as fine
as a human hair through the powdered materialÖidentifying mineralsí crystalline structures based on
how the X-rays diffract. Different minerals are linked to certain kinds
of environments. Scientists will use CheMin to search for mineral
clues indicative of a past Martian environment that might have supported life.
Located on the end of the robotic arm is the Mars Hand Lens Imager or MAHLI. MAHLIís main
job is to acquire color close-up images of rocks and surface materials in Curiosityís
landing area. The MAHLI adjustable-focus, color camera is one of the tools on the turret
at the end of Curiosityís robotic arm. A human geologist uses a hand-held lens to
help identify minerals in rocks. On the rover, MAHLI will provide scientists with close-up
views of minerals, textures, and structures of Martian rocks. The camera takes color images
of features smaller than a human hair. Its focal length can be adjusted to photograph
more distant objects from any positioning of the roverís long arm. MAHLI carries white
light sources and ultraviolet light sources allowing it to function during the day or
night. It is important, even on earth, to understand
the scale of an object being photographedÖ so a well-known object is usually placed in
the photograph. MAHLI will use a special Lincoln penny as one of its reference targets. The
Lincoln penny is a 1909 VBD penny minted the first year pennies were minted.
The calibration reference aboard MAHLI is called the calibration target. It is a plaque
about the size of a smart phone and includes the penny and 2 other calibration targets.
The calibration plaque is attached to a shoulder joint of the arm. In addition to the penny,
2 other calibration targets are used. First , 6 patches of pigmented silicone (guiding
interpretation of color and brightness) and a marked scale of black bars. This will not
appear in the photos but will aid in determining the distance from the camera to a rock and
allow scientists to correlate calibration images.
If cameras are Curiosityís eyes, then the onboard spectrometers make up the roverís
nose. The spectrometers will ìsniff outî the chemical composition of rocks and soil.
Provided by the Canadian government, the Alpha Particle X-Ray Spectrometer or APXS sits at
the end of Curiosityís arm while the main electronics are back inside the body of the
Rover. It will determine precisely what elements are present in a given sample of Martian rocks
and dirt. Curiosity will place the instrument in contact
with samples of interest, and APXS will shoot out X-Rays and helium nuclei. APXS will rely
on 2 techniques to do this. Particle Induced X-Ray Emission (PIXE) and X-Ray Flourescence
(XRF). PIXE relies on the fact that fast moving alpha particles can knock electrons from the
lowest energy levels of atoms right out of the atom itself. This leaves an atom with
an unstable configuration of electrons, and one of the electrons in the high energy levels
of the atom will now drop down to the low level one, emitting an X-Ray as it does so.
APXS has a detector to capture these X-Rays and we can determine the elements in the sample
by looking at the energy of the X-Rays ñ each element emits X-Rays with very specific
energies. APXS contains Curium 244 as a source of alpha
particles. But it also decays into Plutonium 240 which emits X-Rays which in turn can excite
X-Ray emissions in other atoms. This is called X-Ray Flourescence and the idea is pretty
much the same as PIXE except that instead of alpha particles causing the excitation,
this time it is X-Rays. The 2 methods turn out to be very complementary as X-Ray Flourescence
is good for detecting heavier elementsÖas opposed to PIXEís detection of the higher
elements. Spirit and Opportunity were outfitted with
a previous version of APXS and used the instrument to help make clear the prominent role water
has played in shaping the Martian landscape.
The Instruments, Science, Tools, Electronics, Communications, and Power Supply of Curiosity
make up the most complex and comprehensive explorer ever sent to the Red Planet.