Counting Impact Craters on Mars

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NASA has recently finished a study in which they determined the approximate number of asteroid and comet impacts on Mars every year. Using data collected by Mars Reconnaisance Orbiter (MRO) scientists have estimated there are 200 small craters formed every year on Mars as a result of asteroid and comet impacts. These craters measure at least 3.9 meters (12.8 feet) across.

MRO was able to image craters previously detected by itself and other Mars orbiters. Images of the same spots on Mars are taken at different times, thus if an older image does not show a crater, but a more recent one does, we know the impact occured before the most recent image, but after the one previous. This technique allows scientists to more accurately determine the age of craters on the surface.

Understanding the frequency of impacts is important to our understanding of Mars' past and allows scientists to more accurately determine the age of features on the planet. A feature or region with less impact craters is much younger than one with more craters because we know that overtime a feature on Mars will accumulate more impacts. The science will never be perfect, but can at least give us a better understanding of Mars and its development.

For example, scientists will be better able to determine the age of Hadley Crater based on the number of small craters within it. Just look at the image below and you will see that even within Hadley Crater there are multiple smaller craters.

Click to see the original high resolution image from Mars Express [See ESA article]

Previous estimates placed the number of yearly impacts on the Martian surface at 3 to 10 times the amount recently calculated. Those previous studies were done in the 1960s and 1970s and based off studies of lunar craters. MRO's HiRISE Principal Investigator Alfred McEwen says that this new study means "Mars now has the best-known current rate of cratering in the solar system," meaning that of all the bodies in the solar system, Mars is the one we are best able to determine the frequency of asteroid and comet impacts on.

Source:

Dwayne Brown, Guy Webster, Daniel Stolte. NASA Probe Counts Space Rock Impacts on Mars. 15 May 2013.NASA http://www.nasa.gov/home/hqnews/2013/may/HQ_13-142_Mars_MRO_Craters.html (accessed 15 May 2013) 

Mars Travel's Mars Photo of the Day - 15 Sept 2012

Russian Citizen Scientists Have Likely Discovered Mars 3 Lander

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Recently, Russian citizen scientists claimed to have found the remnants of the failed Mars 3 Lander, which landed on Mars on December 2 1971, but had a communication failure after transmitting for only 14.5 seconds. This speculation led the Mars Reconnaissance Orbiter Team to further investigate the proposed sites on March 10 2013. Below you will see an image explaining what they investigated. To see the enlarged version from HiRISE simply click on the image below.

The candidiate descent module/retrorocket can be seen in the image above as well. It had a 4.5 meter chain attaching it to the lander, which is also visible. While the line is 4.8 meters, this difference could be explained if one assumes that it's momentum dragged it slightly across the surface. To best see this feature you will need to view the larger image from HiRISE by clicking on the image above.

The candidate site for the parachute can be seen below. I'm betting you can guess where it is even in this small version, but if you can't just click on it to see the larger high defintion image from HiRISE.



The parachute is the unusually bright spot right in the center of the image, which measures approximately 7.5 meters in diameter. Mars 3 had a paerachute that measured 11 meters in diameter if fully spread out, so a 7.5 meter diameter is consistent in that the parachute would most likely not be completely unfurled. In previous images of the area the parachute was likely covered in dust because the bright spot seen in the most recent image was not there. It's likely that the wind blew dust off the parachute recently, making its white color stand out against the backdrop of the Martian surface.

In 2007 HiRISE took an image of the the predicted landing site for the Mars-3 lander in Ptolemaeus Crater, but according to their website that image "contains 1.8 billion pixels of data, so about 2,500 typical computer screens would be needed to view the entire image at full resolution. Promising candidates for the hardware from Mars 3 were found only very recently." (HiRISE 2013)

The Russian citizen scientists were members of Russia's largest online community about Mars Science Laboratory Curiosity, started by Vitali Erogov. They crowdsourced the preliminary research that led to finding the candidate site for Mars 3. Vitali Erogov then compiled the below graphic of the candidate Mars 3 hardware pieces.

While all of these images match to what would be expected of the corresponding hardware, there is still some investigation to be done. Further analysis of the data, as well as current and future images, will help scientists to verify these findings and potentially determine what caused the communication failure in the first place. While the latter is a long-shot, you never know! For right now though, it looks like we have finally discovered Mars 3!

If nothing else, this just goes to show you the importance of citizen scientists. There is so much data out there it is impossible for scientists to look at it all, but when ordinary people take their free time to examine the data they can make extraordinary disoveries. I encourage every space enthusiast to join one of these citizen science programs by participating in NASA citizen science programs.

One of the biggest programs, whose participants have made numerous historic discoveries is Planet Hunters, which enlists people like you to help discover new planets. Planet Hunters has had and will continue to have enormous impact not only on the scientific community, but on all of mankind, as one day we must find a planet that we can survive on and colonize it, else we keep the fat eof our entire species tied to that of a single planet or solar system.

So if you have some free time, join Planet Hunters and help humanity live on forever!

Mars Solar Conjunction Limits Communication From Earth, Mars

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Due to a Mars Solar Conjunction, an alignment where the Sun blocks the line of sight between Earth and Mars, there will be limited communication with the rovers or orbiters on Mars until May 1 2013.This particular planetary alignment began on April 4. Because of the interference from the Sun, any communications risks getting garbled on its way from Earth to Mars or vice versa. If we were to send a command to a rover and it became scrambled the rover could easily be put in danger, so scientists generally send a large number of sequenced, toned-back commands before Mars Solar Conjunctions.

Diagram Depicting a Mars Solar Conjunction

Both Mars Science Laboratory (MSL) Curiosity and Mars Exploration Rover Opportunity are prohibited from driving, so instead they are tasked with studying their surroundings. The rovers will continue sending brief tones to Earth so that the science teams can assess their safety. NASA's orbiting Mars Odyssey, Mars Reconnaissance Orbiter, and the ESA's Mars Express Orbiter will continue to make observations of the planet, based on pre-input directions, but the latter two will most likely not transmit any data back to Earth until May 1 2013. Mars Odyssey will transmit some data back to Earth over the next month.

This is Curiosity's first time going through a Mars Solar Conjunction, which occurs every two years, but Opportunity has been through a handful of them, so there isn't much to be concerned about. Be sure to check back in on them once communications are reestablished!