Despite being over 154 million miles from Earth, Mars steals the show this month. How does the red planet accomplish this feat from across the solar system? By receiving yet another spacecraft launched by the inhabitants of the planet Earth, that’s how. On Sunday, May 25, the Mars Phoenix Lander will touch down on the Martian surface and continue the scientific invasion of Mars. The Phoenix spacecraft will join NASA’s Mars Odyssey orbiter, the Two Mars Exploration Rovers, Spirit and Opportunity, and the Mars Reconnaissance Orbiter, as well as The European Space Agency’s Mars Express as the sixth spacecraft to continue to try to determine if Mars ever provided a habitat for life.
Phoenix was launched on August 4, 2007, and since then has had a perfectly smooth ride to Mars, which historically has been a very difficult place to operate spacecraft from. One of the problems that makes Mars such a difficult venue for spacecraft and space engineers is its great distance from Earth. In three weeks when Phoenix touches down, the distance between Mars and Earth will be so great that it will take radio messages that travel at the speed of light, over 15 minutes to cover the distance. For example, if an engineer wants to send a signal to the Phoenix to tell it to do something, such as turn left, or trim an antenna position, that command, sent encoded in a radio wave, will take 15 minutes to reach the spacecraft. Then, it will take another 15 minutes for the engineer to find out if Phoenix carried out the intended instruction correctly. A lot can go wrong in 30 minutes across 154,000,000 miles of interplanetary space.
At 7:36 PM EDT, on May 25, Phoenix will, if all goes well, touch down at a gentle 5 mph on Mars. But, the seven minutes before the landing are known to Mars planetary scientists as the seven minutes of terror. These last minutes of the spacecraft’s flight are the toughest because Phoenix will have to decelerate from 12,500 mph to 0 mph in seven minutes. It is a scene that mission controllers have nightmares about. If you visit the Phoenix web site during the landing, you can actually listen to mission controllers as they hear from Phoenix as each flight milestone is reached. I listened to the Spirit and Opportunity landings online and it was far more exciting than any movie I have ever watched—it was just amazing. So by all means, give it a try. By 7:53 PM EDT, we will know if all went well by receiving a tone from Phoenix as it calls home to check in. Visit this web site for live coverage beginning at 7:30 PM : http://www.nasa.gov/ntv.
The Phoenix Lander will be landing in the north polar region of Mars, at 68 degrees north latitude. This is the furthest north or south that a spacecraft has ever landed on Mars. Scientists wanted to finally get a spacecraft to a region of Mars that is expected to have substantial deposits of water ice. In fact, according to Dr. Peter Smith the Phoenix Principal Investigator, “this region contains the highest concentrations of ice on the planet outside the polar caps.†In following the NASA mantra to “follow the water,†planetary scientists believe that because on Earth, wherever we find water we find life, that the best place to look for past and present life is where water is known to exist. Of course, NASA scientists know that Mars is certainly NOT Earth. But, the two planets are very similar in many ways, and maybe, just maybe the same processes that allowed life to take hold on Earth were also operating on Mars millions, perhaps billions of years ago. Recent data show that liquid water may have been present as recently as 100,000 years ago.
Recent missions to Mars like the very successful Mars Exploration Rover mission have taught us that at least at one point in Mars’ past, liquid water existed in many places, and Mars was warmer than it is now. Both rovers, Spirit and Opportunity landed on Mars in January of 2004 with an expected life of 90 days. Four years later, both spacecraft are still functioning and still sending back amazingly detailed photographs and scientific data every day. Despite showing signs of wear and tear, both rovers are expected to survive another upcoming Martian winter and continue to send data back to Earth. The next time you hear someone comment that NASA has lost its edge, remind them of the Spirit and Opportunity rovers that are still hard at work, long after their warranties expired.
While the Phoenix Lander is not a rover and will therefore be unable to move around like the rovers can, it does have a very capable robotic arm that is designed to dig down into the Martian permafrost to find water ice near the surface. Phoenix is also equipped with an advanced chemistry laboratory to conduct detailed chemical tests to assess the Martian soil’s composition of elements that are essential for life such as carbon, phosphorus, and hydrogen, and other organic life signatures. Because of the return of winter to the northern hemisphere of Mars, all of the experiments must be conducted within approximately 90 days of the May 25 landing. So, we should know a great deal about the ability of Mars to support life, both past and present, in a few short months.
To learn more about the Mars Phoenix mission, check out the mission web site at: http://phoenix.lpl.arizona.edu.
UNH observatory public sessions—two public observing sessions are scheduled for this month; one is set for Saturday, May 10, and the other is scheduled for Friday, May 23. Please take note that these sessions and all others planned for this summer and early fall will run from 9 – 11 PM. All public sessions are free and open to the general public. Check the weather before you leave the house for the observatory. If the sky is cloudy, the session will be cancelled. For a complete listing of all of the public sessions for this semester and for this summer, visit the observatory web site at: http://physics.unh.edu/content/observatory. The site includes an image gallery, directions to the observatory, as well as links to all sorts of interesting, astronomical sites.
If you have an astronomical question, send it in to John via email to john.gianforte@unh.edu. All inquiries will be responded to.
