A Smart Bomb For Mars

SPACEDAILY

Sydney - March 21, 2000 -
These were relatively unsophisticated spacecraft that were sent plunging toward the lunar surface. Their only experiment was a battery of high-resolution video cameras that returned steadily more detailed images of the moon as they fell closer to the regolith.

Even today, when computer-generated imagery and action footage is everywhere, seeing an animated sequence of Ranger imagery is exciting.

The lunar landscape gradually grows larger, detail steadily emerges, and finally, the screen turns to static as the probe ends its mission in an untelevised crash.

A Mars Smart Bomb would be just as technically relevant to the scientific community, and even more exciting for the general public. Modern technology also allows such a mission to be carried out more efficiently and cheaply than Ranger.

What would such a mission look like? It would start with a bus ride. The Smart Bomb would be launched aboard a Mars Micromission spacecraft bus for the cruise phase of its mission.

Nobody is totally sure of what such a spacecraft bus would look like, but there seems to be a strong level of consensus in the basic designs.

Look at the preliminary designs from the Jet Propulsion Laboratory and you will see small, slightly curved designs that match the donut-shaped contours of the Ariane 5's secondary payload space.

SpaceDev, a US firm that is developing commercial deep space missions, has proposed a bus that looks similar, and would also ride in steerage class aboard the same rocket. Either one of these vehicles could be modified to carry a Mars Smart Bomb.

The Smart Bomb would rest inside a conical aeroshell that would be attached to the spacecraft bus. As the micromission bus approached Mars, the aeroshell would separate in preparation for atmospheric entry.

The spacecraft bus could either plunge into the atmosphere nearby, or could enter orbit around the planet, depending on mass and fuel limitations.

Entering the atmosphere, the Mars Smart Bomb would decelerate to sub-sonic speeds. A pilot parachute could be ejected earlier than for a standard Mars landing.

It wouldn't last long, but the mission profile would require the probe to be decelerated as much as possible while it is still high above the surface.

After a sequence of parachutes, atmospheric flaps, or whatever is chosen to decelerate the probe, the Smart Bomb itself would emerge and deploy its main parachute.

The Smart Bomb would probably not be large. It could only be a few tens of centimetres in diameter. Its primary instrument will be a high-resolution camera, pointing downwards.

This will return imagery of the Martian surface beneath it. As optional payloads, the probe could also carry pressure and temperature sensors to profile the Martian atmosphere as it descends.

Such instruments can be made relatively light and small, so including them would probably not tax the resources of the mission.

The deceleration of the Mars Smart Bomb during atmospheric entry, coupled with its deployment of a parachute during its descent phase, will ensure that its descent is much slower than a Ranger probe falling through a vacuum.

We would see panoramas of the Martian terrain that are more detailed than an orbiter's view, and broader in scope than surface imagery. Gradually, the images will increase in resolution.

We will be able to compare these close-up pictures with images taken from the Smart Bomb at higher altitudes, and also from orbiters.

Finally, the Smart Bomb will hit the surface in a relatively hard landing. It will carry no retrorockets, airbags or landing legs, but it will still be functional. A simple accelerometer will record the force of impact, generating the final set of data to be collected by the probe.

Next, the probe will begin telemetering its data to an orbiting relay satellite. Some data will be transmitted during the descent phase, but the rest will be stored until a satellite is ready to receive it.

During the descent phase, orbiters will also assist in determining the position of the probe, and signals transmitted after its impact will help to pinpoint its location. A couple of hours after hitting the ground, the Smart Bomb's mission will be over.

The Mars Smart Bomb would not be a very complex spacecraft to design or assemble. Entry technologies for Mars are quite mature. An aeroshell using technology developed for Deep Space 2 could be suitable.

The camera system could be derived from, or be a direct copy of, the Mars Descent Imager (MARDI) carried by the Mars Polar Lander. Rugged power systems, communications hardware and controls developed for the Deep Space 2 penetrators could also be adapted.

The Mars Smart Bomb would be useful for both scientists and engineers. It would provide high-resolution topographic data that could assist in the interpretation of orbiter imagery.

It would provide insights into the Martian atmosphere from not only its on-board instruments, but the behaviour of the Smart Bomb itself as it is influenced by wind.

Finally, it could evaluate the suitability of potential landing sites for probes that would follow. The latter point seems especially important, given the concerns that have been expressed over the terrain at the intended landing zone for Mars Polar Lander.

Mass production of Smart Bombs could lead to a cost-effective series of missions targeted at different regions of Martian terrain. The north and south poles of Mars, with their amazingly dissimilar topographies, are obvious candidates.

Certain regions that are considered too risky for conventional landers would also be attractive targets for a hard-landing probe.

There is nothing exclusively American about the potential of a Mars Smart Bomb. Europe, Japan or Russia could produce such a device. A Smart Bomb would be a novel mission with popular appeal that could be carried out on a relatively small budget. Perhaps even private enterprise could pick up the tab. The idea is out there. Let's make it happen!

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

Click for part one of this report

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