Space agencies around the world are developing missions to Mars, and there�s even the possibility that privately sponsored organisations will send small probes. With this in mind, I propose another potential mission architecture for the near future.

NASA has demonstrated that landing on a small body (the asteroid 433 Eros) was easier than some engineers had expected. The Near Earth Asteroid Rendezvous mission, which was not originally designed to land, reached the surface intact and continued to function after landing. The experience gained by the NEAR mission suggests a small probe could be sent to Phobos, the relatively unexplored largest moon of the planet.

Such a probe would probably be carried all the way to Martian orbit by a larger orbiter, such as a follow-on mission to the European Mars Express. The orbit of Phobos is reasonably close to the equatorial plane of Mars, and a spacecraft piggybacking on a near-equatorial mission would require little more energy to reach its destination. There would be little point in carrying a Phobos piggyback probe on a mission intended for polar orbit, as the orbital plane would be useless for reaching the moon.

The basic infrastructure for carrying a piggyback mission has already been demonstrated by the inclusion of the Beagle 2 lander on Mars Express. A Phobos probe would be of a roughly equivalent size and mass to Beagle 2, resembling a microsatellite. In fact, this could be more than just a passing resemblance. A probe such as this could be built using off-the-shelf technology for its principal components, such as the main platform of the probe. With so many companies developing advanced microsatellite platforms, it should be easy to find a suitable design.

The probe would detach itself from its mother craft after reaching Mars orbit, then make small engine burns to match orbits with the moon. It would descend to the surface and land, taking gradually higher resolution imagery during its descent phase. Accelerometers and a simple spectrometer would collect data on the surface.

Having explored one region, a small engine burn would cause the lander to hop to another location on the moon. Telemetry with Earth would be normally be conducted via another Mars orbiter, such as the parent spacecraft that carried it.

However, one experiment would require Earth stations to lock onto the tiny spacecraft�s weak signal. The Phobos lander would remain fixed in a single location on the moon for a lengthy period while it transmitted a simple carrier wave on a precisely known frequency, allowing its motion to be tracked via doppler shifting (frequency changes) in the signal.

This would provide data for tracking the orbit of Phobos with great precision, as well as monitoring the moon�s own rotation. This information would be valuable for mapping the internal density of the moon, giving clues to its composition.

A piggyback mission with a large equatorial orbiter represents the simplest way to deliver a Phobos probe to Martian orbit. But direct delivery runs to near-equatorial orbit are somewhat rare. In the event that an equatorial orbiter cannot be provided, a Phobos probe could still reach its goal through other means.

It could be carried on a polar orbiter for the Earth to Mars cruise phase of the mission, then detach before the principal orbiter made its deceleration burn. A small motor pack could then be used to decelerate the Phobos probe into equatorial orbit. Several companies are working on propulsion modules for small satellites intended for Earth orbit, and the mission requirements for Phobos could be very similar.

A Phobos probe could even make the cruise phase of its mission solo, after being carried to geostationary transfer orbit around Earth on a commercial satellite launch. The Phobos probe would be a secondary payload on a large launch vehicle. Again, payload assist modules intended for Earth orbital missions could be used in tandem to send the probe on its way to Mars, and to brake it into orbit around the planet.

If funding were sufficient, a Phobos probe could even be launched as the primary payload on a small launch vehicle.

With the potential for using so many off-the-shelf components, a Phobos mission could be attempted by almost any space agency of a reasonable size, or a well-funded space organisation. If Canada is considering joining the current frenzy of international Mars exploration, as some statements have suggested, then a Phobos lander could offer a low-cost option that would be different from any currently planned mission.

Similar designs could also be adapted for other missions to small bodies, and an identical probe could also be used to explore Deimos.

Morris Jones is a Sydney, Australia-based journalist and consultant. He can be contacted at morrisjonesNOSPAMhotmail.com. Replace NOSPAM with @ to send email.

Community
Email This Article
Comment On This Article

Related Links
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express
Mars News and Information at MarsDaily.com
Lunar Dreams and more

Memory Foam Mattress Review

SPACE MEDIA NETWORK PROMOTIONS Solar Energy Solutions Tempur-Pedic Mattress Comparison ... Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News