Mars: Dead or Alive

Posted by Sam Churchill on

The Mars Exploration Rover Spirit is set to land on the red planet tomorrow, January 3, 2004, about 8:35 pm PST. It’s the first of two NASA rovers. Opportunity is scheduled to land on January 24th. They will travel up to 100 meters per Martian day. Each will carry five science instruments. NPR’s Joe Palca reports. Can Mars Support Life? Who knows.

“This mission can’t discover life. It can’t discover ancient life. It can discover whether the building blocks are there and that’s the goal. Now, I mean I suppose in some wild dream, you could find a fossil or something. I guess even more wilder you could see a little green men walking across the surface,” said Mars mission scientist Matt Golombeck.

“Sojourner was our little baby geologist. But it was a baby. And now we’ve got a full-fledged PhD up there on Mars,” Golombeck said.

The $70 million stationary probe, the British Beagle 2, brainchild of Professor Colin Pillinger, was designed to look for direct signs of life, unlike Spirit which will search for places where life may have existed in the past. Still no signs of life from the Beagle.

The $1.09 billion NASA mission includes two rovers, Spirit and Opportunity, at $800 million, three times the cost of the 1999 probes that cratered due to a goof between imperial and metric units.

Since 1971, there have been 13 landing attempts, but only three probes — Viking 1 and Viking 2 in 1976 and Pathfinder in 1997 — have successfully landed on Mars. Messages between JPL and Spirit take about 10 minutes each way. Mars is currently about 106-million miles from Earth. The two rovers have traveled more than 300 million miles getting there.

The rovers will sniff the air, test the soil and probe rocks for signs of past and present life. Pasadena’s Jet Propulsion Lab runs MarsLand, the ultimate theme park.

The new rovers weigh 174 kg and about the size of golf carts compared to the successful but tiny 11 kg Sojourner Rover, about the size of a microwave oven.

The rover landings would mimic the successful 1977 Pathfinder mission’s bouncing-air-bag landing in 1997, but with improvements. The plan:

  • Enter Mars’ 80-mile-high atmosphere at 12,000 mph, protected by a heat shield.
  • Descend to 5 miles altitude and 1,000 mph four minutes later, when a 50-foot-diameter parachute deploys.
  • Improved air bags encase the rover, and rockets brake and stabilize the craft.

NASA’s Deep Space Network, with antennas in Spain, Australia and California’s Mojave Desert, provides the primary backhaul. Among the missions supported by DSN are the Stardust mission that is collecting comet dust today; the Cassini-Huygens mission that will probe the rings and moons of Saturn beginning in July; and the Genesis mission which is collecting solar wind particles for return to Earth in September.

Each DSN complex consists of several deep space stations equipped with large parabolic reflector antennas and ultra sensitive receiving systems that include a 70-meter-diameter (230-foot) antenna; a 34-meter-diameter (110-foot) high-efficiency antenna; at least one 34-meter (110-foot) beam waveguide antenna; and a 26-meter-diameter (85-foot) antenna.

The Mars Relay Telecommunications system links the rover to Earth. The Mars Global Surveyor, launched in 1996, is also in orbit. It uses an 8086 processor for the payload data subsystem, and 1750A processors for the standard controls processor and the engineering data formatter. Data is stored on four 0.75 Gb solid state recorders. Communications with the rovers, is accomplished by relaying data through the Mars orbiter or directly to Earth. About 10 megabytes is sent daily. Communications with Earth are in the X-band (8.4 GHz) using the high gain directional dish antenna, at 11 kbps, and the low gain omni-directional antenna. Communications with orbiting spacecraft are through the UHF antenna.

Power is provided by the solar arrays, generating up to 140 W of power under full Sun conditions. The energy is stored in two rechargeable batteries. An inertial measurement unit provides 3-axis information on position.

BAE Systems manufactured the single board computer, called the Rad6000. BAE Systems designed its chip, the Rad6000, and its successor, the Rad750, specifically for this hostile environment. The rad-hard version of the PowerPC chip, used in some models of Macintosh computers, operates at 20 million instructions per second. Onboard memory includes 128 megabytes of random access memory, augmented by 256 megabytes of flash memory and smaller amounts of other non-volatile memory, which allows the system to retain data even without power. It runs Wind River’s VxWorks operating system and “will tell the rover arm when to move and which direction to move in. It will tell the rover which direction to go when it is driving across the surface of Mars, and how to exchange information with Earth,” said Mike Delliman, Wind River’s lead engineer for the Mars project.

Wind River’s software comes with compilers for C++, Ada, Assembly and other languages that allowed the programmers to write the rover’s specialized routines. The rovers are expected to travel 40 meters, or 132 feet, per day in temperatures that can dip as low as -100 degrees Celsius, or -148 Fahrenheit.

Malin Space Science operates the first Interplanetary wireless ISP. Getting data from the Mars Exploration Rovers (MER) to Earth is tricky. They’ll use three paths to phone home: Direct to Earth, relay through the Mars Odyssey orbiter and relay through Mars Global Surveyor (MGS). The orbiting Mars Relay provides data communication at 401.5275 MHz (F1) and 405.6250 MHz (F2) at 8 kbps and 128 kbps. The Mars Relay cannot send commands to a lander. Rather, it uses a beacon to trigger landers to transmit their data.

Spirit and the orbiters can communicate for about eight minutes at a time, during which they can transfer about 60 megabits of data. Back on Earth, NASA scientists are receiving as much as 150 megabits of data daily from the rover and orbiters.

The Spirit and Opportunity rovers carry a suite of instruments for science and navigation. The panoramic camera (Pancam) and navigation cameras are mounted on top of a mast, about 1.4 meters above ground level. Each Pancam uses a a 1024 1024 CCD with an effective f/20, 43 mm lens and a field of view of 16 16 . The mast, mounted at the front of the equipment deck, also acts as a periscope for the Miniature Thermal Emission Spectrometer (Mini-TES).

Dalsa, based in Waterloo, Ontario, Canada, makes the video components and made the CCDs for the Pancam and other cameras on Spirit and Opportunity. Scientific Imaging Technologies (SITe), based in Tigard, Oregon, makes CCDs used in the Hubble Space Telescope.

Attached to the end of the instrument deployment device on the Sprit are the Alpha Particle X-Ray Spectrometer (APXS), Mossbauer Spectrometer (MB), Microscopic Imager (MI), and Rock Abrasion Tool (RAT). A magnet array is attached to the front of the equipment deck. Two hazard avoidance cameras are mounted on the front of the rover and two on the rear. The group of science instruments (Pancam, Mini-TES, APXS, MB, MI, and RAT) is known as the Athena science package. Bill Nye, the Science Guy got NASA to add a Sundial.

NASA’s rover site and JPL will provide daily images from each rover. SGI Onyx 300 computers assemble the 360 panoramas. To cope with the expected interest, NASA is relying on 1300 internet servers around the world to provide information on the missions. The two rovers will send back pictures about four times sharper than those taken in 1997 by the Sojourner.

Mars airplanes have been proposed. On August 9th, 2001, a Mars airplane prototype was released from a balloon at 103,000 feet over Tillamook, Oregon. It took two hours to reach ground through the thin, Mars-like atmospheric conditions. The NASA Haughton-Mars Project (right) studies of the Haughton impact crater as a prelude to a manned mission to Mars. Devon Island, in the high Canadian arctic, is the largest uninhabited island on Earth. The Haughton impact crater, on Devon, was formed 23 million years ago, but what hit it is still unknown. Principle investigator, Dr. Pascal Lee is also a helicopter pilot.

In 2011 NASA plans to bring Martian soil back to Earth. The International Committee Against Mars Sample Return (ICAMSR) wants to stop it. The Mars Exobiology strategy is being executed with the help of Planetary Protection Officer for Mars, Bill Horsley, who must prevent contamination between Earth and Mars. It’s not immediately clear who resolves jurisdictional disputes between Planetary and Solar System Protection Officers.

After living in the dirt of Mars, a pathogen could see our bodies as a comparable host,” says John Rummel, Planetary Protection Officer for Earth. John Barros thinks extraterrestials should go to the University of Washington for Astrobiology study.

[Pardon me, John, but what’s wrong with Long Term Ecological Research around volcanos and hydrothermal vents? During a September field test, NASA used Wi-Fi cells from Tropos Networks to deliver 1 megabit/sec at Meteor Crater, Arizona. Intel’s motes and nanotechnology are waiting for intelligent life to discover them. – Sam]

Astrobiology Magazine features The Martian Cronciles, a multipart series, showing the inside story of the Mars mission. Portland State University’s Sherry Cady (left), an Astrobiologist in Portland, edits the more academic Astrobiology Journal.

The Japanese Nozomi probe was fried by the recent solar storm and is now largely inoperable. The outcome of the Spirit landing will be featured in a TV special, Mars Dead or Alive, airing January 4, 2004, at 8 p.m. ET Sunday on PBS. NPR’s Science Friday has radio coverage. Science Museums like The Tech and OMSI will have special Mars Parties.

Mars Today,, Spaceflight Now, The Planetary Society, Nasa Watch (not a Nasa site), Houston Space Chronicle, Encyclopedia Astronautica, Nasa homepage, Welcome to the Nasa Web, Nasa Human Spaceflight (shuttle homepage), Kennedy Space Center, Mars Global Surveyor, Galileo: journey to Jupiter, European Space Agency, United Nations Office for Outer Space Affairs, British National Space Centre, Search for Extraterrestrial Intelligence (SETI), and Space Ref have the latest. Daily Wireless has more on The Beagle 2, The Mission to Mars and the 1999 Mission to Mars.

NASA and mesh-based Tropos networks used IPerf network monitoring tools to test communications between a server at a simulated base camp and a mobile test computer at its annual space simulation exercises in the Arizona desert (above).

Posted by Sam Churchill on Friday, January 2nd, 2004 at 2:00 am .

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