In my previous column last Sunday, I made an argument that sending robots to Mars to look for signs of Martian fossils and/or life would be less expensive and less perilous than sending humans to Mars.

Such a mission might be accomplished five to 10 years before a manned Mars mission could be sent. What makes a manned mission to Mars difficult is the long travel time between Earth and Mars of over six months.

About every 15 days, the amount of food, water and oxygen needed to keep one human alive equals that human’s mass. So in six months, the human supplies will amount to 12 times the human mass times the number of crew.

If one spends a year on Mars waiting for a window to travel back to the Earth, followed by another six month trip back to Earth, the essential supplies needed will be 48 times the mass of the humans.

Two years away from Earth’s protective magnetosphere will also take a toll on the genetic matter of the humans. If robots are sent instead of humans, a considerably smaller vehicle will be needed to make the same mission.

To make use of the Earth’s velocity of 18.5 miles per second around the sun, the Mars vehicle has to add several miles per second to its orbital velocity around the sun.

This will put the Mars vehicle on an elliptical orbit that will reach to Mars’ orbit on the far side of the sun. (This takes six months.)

Then the next rocket firing will slow down the orbital motion of the Mars vehicle to that of Mars’ motion and also put the Mars vehicle in orbit about Mars.

As with the Apollo missions, the Mars vehicle will separate into a Mars orbiter and a Mars lander. Another rocket firing will put the Mars lander into a spiraling path down to Mars’ surface.

Part of the lander will act as a heat shield against Mars’ atmosphere as it drops closer to Mars’ surface. Small rocket bursts will ensure that the lander comes down in the desired area.

Several stages of parachutes will further slow down the descent. As it nears the surface, air bags will inflate to further cushion the landing impact.

The lander will include a number of specialized robots of high dexterity with two legs, two arms, a powerful on board computer (a “brain”) and two high definition cameras for depth perception.

These cameras will access on board programs that will allow identification of likely Martian rocks that may contain fossils. There will be a water prospector/extractor powered by a solar mirror that will drill into the Martian surface, apply heat and extract Martian water.

The site selected will be one where there is likely much permafrost, increasing the likelihood of past Mars life and allow much water to be collected.

Then the water will be electrolyzed (broken into hydrogen and oxygen gas) using a large solar panel; these gases will be used to synthesize liquid fuel needed for the Mars return vehicle.

The likely Mars samples will be scanned by devices similar to those used by TSA at our airports for the presence of organic materials and gas emission. So only the best samples will be returned to Earth.

Collection of Mars samples will continue all through the year long mission on Mars’ surface. By then sufficient fuel will be have been synthesized to power a Mars return mission. The robots will be left behind with the other Mars equipment.

The Mars return mission of several hundred pounds of rocks will first go into Mars orbit.

Much of the data collected on Mars surface will be wirelessly transferred to the Mars orbiter and then over months transmitted back to Earth. The Mars orbiter will have a large solar panel and antenna to allow a high transmission rate of images and scientific data.

Another firing of rockets will put the Mars return mission into an orbit around the sun that will take it back to Earth’s orbit. The return capsule will use its remaining fuel to orbit Earth and rendezvous with the Space Station.

The precious supply of Mars rocks will be transferred to the Space Station. Eventually the rocks will reach geological laboratories on Earth to be studied intensively.

SKY SIGHTS IN COMING WEEK: Last night’s Harvest Moon will provide us with extra evening moonlight through mid week.

In the last hour of the evening, the bright planet Jupiter shines steadily in the east, near the bright star Aldebaran of Taurus. Venus is a wondrous sight in the eastern dawn, rising more than three hours ahead of the sun.

My last Science Sunday presentation for September (half-hour talk on local mammals) will be this afternoon at 4 p.m. in Compton 224. There will be tours of the Science Discovery Center afterwards for those interested.

Next month’s talk will be on European mammals. These talks are free to the public. Please arrive a few minutes earlier.

Compton is our large science building, next to the large construction area where the CCIT building will stand (with new planetarium facility).

Bob Doyle invites any readers comments and questions. E-mail him at rdoyle@frostburg.edu . He is available as a speaker on his column topics.