365daysDate: May 22, 2009

Title: Mars Exploration: A Quick History


Podcaster: Susan and Amanda Murph

Organization: Susan and Amanda Murph from How to Grow Your Geek: Parenting and More!

Description: In honor of the Mars Solstice, Susan Murph and her 9 year old daughter Amanda give us a quick history lesson on what we know about Mars, and the missions that have provided us with that valuable information.

Bio: Susan is also a life-long sci-fi, fantasy and science geek, and loves to incorporate her favorite hobbies into her current career of raising her two kids as a stay-at-home mom. She believes that including her kids in her hobbies not only strengthens her relationship with them, but also benefits their development of useful skills such as critical thinking, logic, creativity and reading comprehension, just to name a few. Susan currently hosts and produces the “How to Grow Your Geek” podcast.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by [brief dramatic pause] Anonymous on behalf of The Onion Router Project. The Onion Router Project provides free, open source software securing privacy on the Internet for all of Earth’s inhabitants. Find out more at

Susan: Hi, my name is Susan Murph, and I am the host of How to Grow Your Geek: Parenting and More! My daughter Amanda and I enjoy studying space and astronomy, and in honor of the solstice on Mars today, we are going to tell you some of what we know about Mars, and how we discovered it!

Amanda, what can you tell me about Mars?

Amanda: Mars is the closest rocky planet to earth and it looks red due to the iron oxide in the rocks. It also has 2 moons, Deimos and Phobos, that are both lumpy and lop-sided.

Susan: Does it have air?

Amanda: No, it only has 0.6 the atmosphere of earth, so you can’t breathe on it. You could wear a scuba suit and breathe, but the radiation would kill you.

Susan: What? Radiation? Why?

Amanda: Mars doesn’t have a magnetic field to protect it from solar radiation, so you would be exposed to deadly rays, unless you had a lead suit. It is also pretty cold most of the time, so you would need a heavy coat over that, which is a lot to wear. But Mars has less gravity than earth, so it would be easier to walk on Mars.

Susan: How do you know all of this?

Amanda: I have learned it from school, television and the Internet.

Susan: But where did all of those places get their information about Mars?

Amanda: I don’t know – where?

Susan: Well, we have sent a lot of spacecraft to explore Mars. Not all of them have been successful reaching Mars or landing safely, but the ones that performed as planned have greatly increased our knowledge of Mars. I’ll tell you about some of the most successful missions we have had to Mars.

The American probe Mariner 4 in 1967 was the first craft to reach Mars successfully, and it took 20 pictures, plus it studied the cosmic rays and magnetic fields from space. In 1971, Mariner 9 entered orbit, and took 7000 images, mapping over 80 % of the surface of Mars, finding the largest mountain humans have ever seen, Olympus Mons, and the Grand Canyon of Mars, Vallis Marineris, which was named after the probe.

But the most successful early missions were the Viking probes. Designed to have both an orbiter and a lander, these probes were able to take pictures and do tests not only from space but also on the surface. The Viking probes reached Mars in the summer of 1976. The Viking 1 lander functioned for over 6 years. Viking 2 ‘s lander functioned for over 3 ½ years Together, the missions provided the first real database of information we learned about the conditions and chemical makeup of Mars, as well as our first pictures from the surface. One thing that the Viking missions were looking for was evidence of life on Mars. Instead, those tests were inconclusive, but we got back interesting information about Mars’ chemistry. The Viking’s information was our best source until new the late 1990’s brought a new round of explorer craft.

And now we get to the ones I remember being excited about!

Amanda: What were those missions?

Susan: The Mars Global Surveyor entered orbit in 1997. It was designed to orbit and survey the entire planet, providing data on the terrain, natural features, atmosphere, gravity and magnetic field of Mars, as well as photographing the moons of Mars and other spacecraft. Originally planned for a 2 year mission, the surveyor was so successful that it was extended for 4 more years, and then served as a communication satellite for the lander craft that followed.

Next came the Mars Pathfinder mission, one of my favorites. I was sitting inside, glued to the television, on July 4, 1997, missing a barbecue, to watch as this landed.

The craft dropped into the atmosphere of Mars, and launched its parachute, and then, when it got close enough, deployed and airbag system to cushion the lander, which bounced across the Ares Vallis floodplain of Mars. We all held our breath as we awaited confirmation that it had landed safely, and cheered when the lander opened up and began transmitting its landing data. Soon, the beach-ball sized rover, named Sojourner, was able to begin its travels across the plain, albeit very slowly. Expected to function for a week to a month, Sojourner gathered information for 3 months before the cold Martian winter overtaxed its batteries. During its mission, it gathered much data about the climate and geology of its landing area.

And now we get to the missions, most of which are still operational in space or on the surface of Mars.
In February, 2002, the Mars Odyssey began orbiting while using imagers and spectrometers to hunt for evidence of past or present water or volcanic activity. It predicted the presence of water ice in 2002, which was confirmed by later missions, and also acts as a communications relay satellite for all of the other lander craft since.

Reaching orbit in 2004, the European Space Agency craft Mars Express began taking wonderful pictures with its high resolution camera, while unfortunately losing its lander, the Beagle 2. The orbiter continued its mission, discovering methane and traces of ammonia in the atmosphere, which could be indicators of microbial life.

Amanda: If that mission lost its lander, how can we find out more on the surface of Mars?

Susan: The next two missions have done a lot to study the surface. The Mars Exploration Rovers have been wonderfully successful little machines, and its missions studying the rocks on Mars, looking for signs of water and iron, erosion and volcanic activity, among many other tasks, have been incredible. Spirit and its twin Opportunity arrived in 2004 on opposite sides of the planet, and took many pictures while traveling and studying interesting formations. Originally planned to have missions lasting only 90 Mars days, these rover have continued to function, with only a few interruptions, from their arrival to the present. Dust buildup on the rovers’ solar arrays is periodically blown off by the dust devils that were witnessed by the rovers, increasing their battery charge. These little rovers have shown little sign of giving up, and they are taking on longer drives to interesting sites.

And finally, the last two missions we will discuss today. First, the Mars Reconnaissance Orbiter, which reached orbit in 2006, which was designed to monitor weather and surface conditions, study potential landing sites and provide a new communications system for relaying transmissions back to Earth. The most exciting piece of equipment on the orbiter is the HiRise telescope camera, which can obtain the best resolution pictures of any camera sent to Mars yet, but the orbiter also contains spectrometers and a radar system for studying the polar regions of Mars in the search for liquid water.

And last but not least, we have the wonderful Phoenix lander, which has made some of the most amazing discoveries on Mars yet. Upon its arrival at Mars in 2008, the Phoenix landing was captured by the MRO HiRise camera, allowing us to view its decent and landing in the ice-covered Green Valley. During its mission, it scooped dirt and what turned out to be water ice for chemical testing, and confirmed the presence of water vapor, as well as the discovery of perchlorate on the surface of Mars.

The lander went quiet in October, 2008, due to lack of solar power caused by the Martian winter. It will try to start back up later, but is likely to be trapped in the ice. But it contributed many megs of data to be studied about the wind, weather, soil composition, and other information to study for years.
And there are more missions being planned, so keep your eyes open and looking at Mars!

Amanda: We hope you have enjoyed our presentation, and if you would like to hear more from us, please visit

Susan: Thanks so much, and please have a Happy Mars Solstice, and a great Year of Astronomy!

End of podcast:

365 Days of Astronomy
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