Planet-B will be carrying a Canadian-designed and Canadian-built Thermal Plasma Analyzer (TPA), an atmospheric probe which will measure low-energy particles and gases considered vital to the understanding of the origin and composition of the Martian atmosphere. This mission will also be the first time Canada participates in an interplanetary mission.
"This is a milestone in the Canadian Space Program and an historic moment for all Canadians," said Dr. Ron Duhamel. "A Canadian experiment is on its way to Mars to study the atmosphere which will help us better understand our own environment. Our expertise in atmospheric research and the excellent reputation of Canadian space scientists has led to this invitation from Japan. This is the first time Canada has sent an instrument as part of an interplanetary mission and its success should lead to more international collaboration with our partners."
The Canadian Space Agency is funding this research with the participation of scientists from the University of Calgary, as well as from the Universities of Alberta, Western Ontario, and Victoria. The Co-Principal Investigators of the Canadian Thermal Plasma Analyzer (TPA) are Dr. Andrew Yau and Dr. Greg Garbe, professors of physics and astronomy at the University of Calgary. "The launch of the Canadian probe marks a new chapter in Canadian space exploration," said Dr. Yau. "As the first Canadian instrument to orbit another planet, the TPA sets the stage for Canada's participation in future international planetary missions in the coming millennium." Others on the research team include scientists from Hokkaido, Nagoya, and Tokyo.
The Canadian Thermal Plasma Analyzer (TPA) consists of a sensor mounted at the end of a boom and a central Power and Controller Unit inside the satellite. Once the satellite reaches Martian orbit, the boom will unfold and extend the sensor away from the spacecraft. This isolation is necessary in order to ensure that the instrument performs without interference from the spacecraft.
"Canada's participation in missions to Mars is a large step toward the future when humans will be going to the Red Planet," said CSA Astronaut Chris Hadfield. "As an astronaut and also as an explorer, I'm proud the Canadian Space Agency is involved in this global exploration of Mars and am very excited by the important data this probe will send back to Canadians and the world."
This international interplanetary exploration mission is sponsored by Japan's Institute of Space and Astronautical Sciences with instrumentation from Canada, Japan, Sweden, Germany, and the United States. Participation in this mission provides Canadian researchers with the data from all the other experiments on Planet-B.
Headquarters, Washington, DC
Goddard Space Flight Center, Greenbelt, MD
Institute of Space and Astronautical Science (ISAS) of Japan
July 1, 1998
"The Neutral Mass Spectrometer will enable us to measure the chemical composition of the upper atmosphere of Mars on a global scale, which has never been done before," said Dr. Hasso B. Niemann, the NMS principal investigator at NASA's Goddard Space Flight Center's Laboratory for Atmospheres in Greenbelt, MD. Previous upper atmospheric composition measurements were done in only two locations as NASA's Viking landers entered the Martian atmosphere on July 20 and Sept. 3, 1976, respectively.
The radio science hardware was built by the Johns Hopkins University Applied Physics Laboratory in Laurel, MD, under contract to NASA. The ultra-precise signals generated by the oscillator serve as a very accurate clock to enable analysis of the Martian atmosphere and to help guide the spacecraft as it orbits the red planet.
Planet-B is designed to perform long-term studies of the upper Martian atmosphere and ionosphere, and its interaction with the solar wind. Launch of Planet-B is scheduled for 2:12 p.m. EDT on July 3. After launch, the Planet-B spacecraft will be placed into Earth orbit and will use two swingbys past the Moon to establish conditions for a final trajectory to Mars.
Once the spacecraft reaches Mars, which is now scheduled for Oct. 11, 1999, it will be placed into a highly elliptical or "egg- shaped" orbit stretching from 93-186 miles (150-300 kilometers) to about 17,000 miles (27,300 kilometers) above the surface. The low-altitude portion of the orbit will be used for remote sensing of the lower atmosphere and surface, and for direct measurements of upper atmosphere and ionosphere. The more distant parts of the orbit will allow instruments to probe the ions and neutral gas escaping from Mars, which interact with the charged-particle "wind" blowing outward from the Sun. Ionization of the upper atmospheric gas by solar radiation produces the charged-particle atmosphere (ionosphere) that acts as an obstacle to the solar wind.
This radiation produces species of gas not seen in Mars' lower atmosphere, such as nitric oxide, or dissociates the atmosphere into single atomic species, such as atomic oxygen. If these neutral or ionized species possess enough energy, they can escape the gravitational pull of Mars, resulting in a net atmospheric loss. Measurements of lighter species such as atomic hydrogen and deuterium also can provide clues about the evolution of the Martian atmosphere.
Mars has little or no intrinsic magnetic field to interact with this process, making it more like Venus in this respect than Earth. The upper atmosphere of Venus and its solar wind environment were studied for almost 14 years by the U. S. Pioneer Venus Orbiter spacecraft from a similar, highly elliptical orbit. The Planet-B NMS instrument is a state-of-the-art enhancement of the Pioneer Venus mass spectrometer, weighing only six pounds (2.8 kilograms). To conserve space and weight, electronic items such as transistors and integrated circuits were removed from their outer casings and placed in larger packages called hybrid circuits.
Data from previous Mars exploration spacecraft such as Mariner 9 indicate that dust storms near the surface can heat the lower atmosphere and increase the gas density in the upper atmosphere where Planet-B will make its measurements. The U.S. Mars Surveyor 1998 mission known as the Mars Climate Orbiter, due for launch this December, carries an instrument called the Pressure Modulated Infrared Radiometer, which will provide complementary information on the lower atmosphere and its response to dust storms.
The Planet-B project is managed by the Institute of Space and Astronautical Science (ISAS) within the Japanese Ministry of Education. Planet-B carries 14 instruments from Japan, Canada, Sweden, Germany and the United States. ISAS personnel will operate the spacecraft and its instruments. The spacecraft was built by the Nippon Electric Corporation and will be launched by the new M-5 rocket. This rocket is designed to expand Japan's launch capability for the inner planets and beyond.
Further information on the NASA portion of the Planet-B mission and related graphics can be obtained via the Internet at the following URL:
http://webserver.gsfc.nasa.gov/Code915/planetb.html
The Planetary Society
June 26, 1998
On July 4, 1998 -- a year after Mars Pathfinder successfully touched down on the Red Planet -- another mission to Mars is set to make history.
The Planet-B orbiter to Mars is slated for launch on July 4, 1998 (Japan Standard Time). This new mission heralds a series of Japanese space science missions to explore the inner planets, Moon, and near-Earth asteroid Nereus. The $100 million spacecraft has 14 instruments to study the upper atmosphere of Mars and its interaction with the solar wind. The probe also will take images of the Martian surface and the planet's two moons.
In 1985, ISAS launched its first two interplanetary spacecraft, Sakigake and Suisei (Planet-A), to explore Halley's Comet. Subsequent probes investigated Earth's black Moon, solar flares, and magnetic field. Building on these achievements, Japan is now poised to begin a more ambitious series of planetary missions, beginning with the Planet-B probe to Mars. Japan's goal is to launch one scientific mission every year.
The 540 kilogram (1,190 pound) Planet-B spacecraft will be lofted into an elliptical orbit around Earth using Japan's M-5 launch vehicle. To accommodate the mission's rigorous weight constraints, the craft will use gravity assist trajectories. It will fly twice around the Moon, swing past Earth to gather speed, then slingshot to Mars. Following a ten-month journey, the vehicle will be inserted into orbit in mid-October of 1999 to begin a two-year mission (Earth years).
Planets in our solar system have diverse atmospheres. Venus has a dense atmosphere composed mostly of carbon dioxide and is experiencing a runaway greenhouse effect. Earth's atmosphere is mainly nitrogen and oxygen. Mars has a thin atmosphere of carbon dioxide, with trace amounts of water vapor. The gaseous outer planets are mostly hydrogen and helium. The large moon of Saturn, Titan, has an atmosphere which includes many hydrocarbon compounds.
Scientists believe Mars, during its early history, was wet and warm, with a thicker atmosphere of carbon dioxide. Today, the planet's atmosphere is thin (0.7 percent as dense as Earth's atmosphere) and dry. Scientists theorize that Mars, about half the size of Earth, cooled more quickly, limiting volcanic activity and recycling the supply of carbon dioxide. Gradually, the atmosphere attenuated and temperatures dropped.
Scientists want to better understand what caused Mars' climate change. By studying the dynamics and evolution of Mars' atmosphere, they will be able to better understand Earth's atmosphere and possible threats to climate stability. The Planet-B mission complements NASA's Mars Global Surveyor, which currently is investigating the planet's lower atmosphere and surface.
Several countries are contributing additional instruments, including a mass spectrometer from NASA's Goddard Space Flight Center; radio science equipment from Johns Hopkins University; thermal plasma analyzer from Calgary University; ion mass spectrometer from Sweden; dust counter from Munich Technical University, and a data compression kit for the CCD camera from France.
The probe's camera will take images of the martian surface, and of the planet's tiny moons, Phobos and Deimos. The complete instrument package weighs only about 35 kilograms (77 pounds). The vehicle will be launched from Kagoshima, on the island of Kyusha in southern Japan.
Muses-C -- This spacecraft is set to launch in 2002 to the near-Earth asteroid Nereus. The probe will rendezvous with and land on the small body, collect rock and soil samples, then head back to Earth, arriving in early 2006.
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