Two small science probes will be sent to Mars in 1999 to demonstrate innovative new technologies brought to the forefront by NASA's New Millennium program.
Under terms of a new agreement between the New Millennium and Mars Exploration programs, the microprobes will hitchhike to Mars aboard NASA's 1998 Mars Surveyor Lander.
"A successful demonstration of the microprobe technologies will enable a wide range of scientific activities that would not be affordable with conventional technologies," said Dr. John McNamee, manager of the 1998 Mars Surveyor Lander and Orbiter project at NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA.
"In particular, scientific investigations which require a relatively large number of surface stations distributed over the surface of Mars, such as seismic or meteorology networks, will be made possible by the microprobe concept," McNamee said. "In addition, microprobe penetrators may be the most efficient and effective way of obtaining soil samples and measurements from below the sterilized Martian surface."
In the process of enabling future characterization of the Martian climate by a meteorological network, the Mars microprobes will complement the climate-related scientific focus of the 1998 Mars Surveyor Lander by demonstrating an advanced, rugged microlaser system for detecting subsurface water. Such data on polar subsurface water, in the form of ice, should help put limits on scientific projections for the global abundance of water on Mars.
Future missions to the planet could use similar penetrators to search for subsurface ice and minerals that could contribute to the search for evidence of life on Mars.
The 1998 Mars Surveyor Lander will be launched in January 1999 and spend 11 months en route to the Red Planet. Just prior to its entry into the Martian atmosphere, the microprobes, mounted on the spacecraft's cruise ring, will separate and plummet to the surface using a single-stage entry aeroshell system. Chosen for its simplicity, this aeroshell does not separate from the microprobes, as have traditional aeroshells on previous spacecraft, such as the Mars Pathfinder and the Viking landers of the mid-1970s.
The probes will plunge into the surface of Mars at an extremely high velocity of about 446 miles per hour (200 meters per second) to ensure maximum penetration of the Martian terrain. They should impact the surface within 120 miles (200 kilometers) of the main Mars '98 lander, which is targeted for the planet's icy south polar region.
Upon impact, the aeroshells will shatter and the microprobes will split into a forebody and aftbody system. The forebody, which will be lodged between one to six feet underground, will contain the primary electronics and instruments. The aftbody, connected to the forebody by an electrical cable, will stay close to the surface to collect meteorological data and deploy an antenna for relaying data back to Earth.
The microprobes will weigh less than 4.5 pounds (2 kilograms) each and be designed to withstand both very low temperatures and high deceleration. Each highly integrated package will include a command and data system, a telecommunications system, a power system, and primary and secondary instruments. Nearly all electrical and mechanical designs will be new to space flight.
"In addition to a team of industrial partners that will help develop advanced technologies to be demonstrated during the mission, we have just selected Lockheed Martin Electro-Optical Systems as a primary industry partner to participate in the integration and test program for the microprobes," said Sarah Gavit, Mars microprobe flight leader at JPL.
Technologies proposed for demonstration on this second New Millennium flight include a light weight, single- stage entry aeroshell, a miniature, programmable telecommunication subsystem, power microelectronics with mixed digital/analog integrated circuits, an ultra low- temperature lithium battery, a microcontroller and flexible interconnects for system cabling.
In-situ instrument technologies for making direct measurements of the Martian surface will include a water and soil sample experiment, a meteorological pressure sensor and temperature sensors for measuring the thermal properties of the Martian soil.
"The Mars microprobe mission will help chart the course for NASA's vision of space science in the 21st century, a vision that incorporates the concept of 'network science' through the use of multiple planetary landers," said Kane Casani, manager of the New Millennium program. The probes will become the first technology to be validated in this new network approach to planetary science.
"Networks of spacecraft will address dynamic, complex systems," Casani said. "For example, a single lander can report on the weather at one spot on a planet, but a network of landers is needed to characterize the planet's dynamic cclimate. Similarly, a single seismometer will indicate if a quake has occurred on a planet, but a network of seismometers can measure the size of a planetary core. We need multiple spacecraft to go beyond our initial reconnaissance to completely characterize dynamic planetary systems the way we are able to do on Earth."
The New Millennium program is managed by JPL for NASA's Office of Space Science and Office of Mission to Planet Earth, Washington, DC. The Mars `98 lander, managed by JPL for the Office of Space Science, is in development at Lockheed Martin Astronautics Corp., Denver, CO, under contract to JPL.