How long does it take to send a signal to SAM on Mars?

That varies depending on where Mars is compared to the Earth on their respective paths around the Sun. The distance between Mars and Earth is constantly changing. Because Mars is farther from the Sun, it takes longer for it to orbit the Sun than the Earth does. Actually, it takes Mars twice as long to orbit the Sun than the Earth. (You can visit NASA's Eyes on the Solar System - eyes.nasa.gov - to help visualize the orbits and time it takes each planet to travel around the Sun.) When both planets are on the same side of the Sun, the distance between Earth and Mars can be as short as 54.6 million km, and when the two planets are on opposite sides of the Sun the distance between them is as great as 401 million km. When we send a command to SAM from Earth, that message travels as a radio wave, which travels at the speed of light (3 x 10⁵ km/sec). The time it take to get the message to SAM can be as short as 3 minutes, or can take up to 22 minutes to send that message to Mars.

The exploration of habitable environments on Mars, including an assessment of the preservation potential for organic compounds of either abiotic or biological origins in martian rock, regolith fines, and the atmosphere, is one of the key goals of the Mars Science Laboratory (MSL) mission which landed the Curiosity Rover in Gale Crater on August 6, 2012. The Curiosity rover contains the Sample Analysis at Mars (SAM) instrument suite that is conducting the most extensive search for inorganic volatiles and organic compounds in the martian atmosphere and surface soil and rocks since the Viking missions that landed on Mars in 1976. The first soil sample from the martian surface collected by Curiosity at a location called Rocknest, was delivered to the SAM instrument on the 93^rd martian day (called a Sol) after landing. The Rocknest soil sample was heated by SAM to a temperature over 830°C and the composition of the gases released from the sample were determined by mass spectrometry. One of the major gases released from the Rocknest soil was oxygen (O₂), which evolved over a broad temperature range from ~200 to 500°C. At the same time that O₂ was released, several chlorinated organic compounds including chloromethane and dichloromethane were also detected by SAM which points towards the decomposition of an oxygen and chlorine containing substance in the soil, such as perchlorate (ClO₄)^-. When heated to high temperatures, perchlorate can become a powerful oxidant which can destroy or decompose any organic material present. On Earth, perchlorate is both naturally occurring and manmade and is commonly used as an ingredient in solid rocket fuels, explosives, safety flares, and fireworks. In 2008, perchlorate was also identified by the Phoenix mission in the Northern latitudes at the ~0.5 wt.% level, an amount of perchlorate that only occurs naturally at similar levels on Earth in specific nitrate ores from the Atacama Desert in Chile. The detection of perchlorate by SAM in the surface soil at yet another location on Mars is a very important discovery and indicates that perchlorates may be globally distributed across the entire martian surface. I am really looking forward to future discoveries by SAM as Curiosity continues to explore Gale Crater.

I had the privilege of attending the 44th annual LPSC meeting which brings together experts in broad disciplines including petrology, geochemistry, astrobiology, geophysics, geology and astronomy to discuss their cutting edge research. Being new to planetary science, I learned a great deal from the oral presentations and posters presented this year.

As a member of the ExoMars Rover science team, I had a great interest in hearing the latest results from the Curiosity rover, which had three separate sessions dedicated to the experiments conducted in the first 100 sols (a .sol. is a day on Mars). Here we learned more about the morphology of the Golburn, Link and Hottah formations. Geologists feel that the rounded pebbles embedded in the sandstone compares directly to alluvial fans seen in the Atacama desert, a common analog site to Mars found here on Earth. Hottah.s big cracks in the cement-like structure imply that there was rapid fluid motion in these areas, lending credence to the idea of this being the ancient riverbed site.

We also learned more about the samples scooped at the Rocknest sand-shadow site, including the diversity of chemical compounds (including some chlorinated hydrocarbons!) that SAM uncovered. Work is still being conducted on the SAM testbed (a replica of the SAM instrument suite sent to Mars kept at NASA Goddard Space Flight Center) to determine whether the source of the hydrocarbons is terrestrial (i.e. we brought it with us) or is Martian-derived. However, given this and the presence of water found in the evolved gas analysis of the Rocknest samples, as well as the presence of various redox states of sulfur and nitrogen-bearing compounds, the Curiosity science team felt they had enough evidence to declare that the area could be deemed .habitable.. This is an incredible result! It means that the work should continue in this region to search for martian organic molecules.

And if you want to dig even deeper into the scientific data yourself, I found out that data from the Mars Science Laboratory will be released via The Analyst.s Notebook found online here: http://an.rsl.wustl.edu/msl

The SAM and Curiosity teams recently participated in MarsFest, a festival held each year in Death Valley National Park that celebrates the rich history of Mars science and engineering research in the Park. The 2013 festival took place from March 1-3. The event included scientist- and ranger-led field trips to martian analog sites, planetary science talks and discussions, an expo with booths and demonstrations from a number of planetary science groups and organizations, and an evening planet-viewing event.

Ranger Carrie Hearn teaches visitors about the geology of the Badwater basin by leading them in a dance. The dance was part of a field trip co-led by Carrie Hearn and Andrea Jones that tied together NPS perspectives and NASA connections to field trip sites.

SAM E/PO team members Lora Bleacher and Andrea Jones helped plan and organize the festival, and the SAM Electrical Lead Florence Tan traveled out to the festival with Andrea Jones to support festival activities. The SAM E/PO team presented information about the festival at the Lunar and Planetary Science Conference in Houston, Texas the week of March 18-22. The abstract is available here. A note that several more people from Death Valley National Park played an exceptionally large role in festival planning and organization after this abstract was written, in particular, Amy Thickpenny, Carole Wendler, and Vicki Johnson.

SAM Electrical Lead Florence Tan talks about SAM and Curiosity with visitors at the 2013 MarsFest Expo.

Gale Crater, where Curiosity landed, presents us with wide variety of geology. A group of scientists on the science team have been working to create a geological map of this region and tackling the big challenge of interpreting this map to understand the geological history of Gale Crater. On one side of the landing site is the river, know as Peace Vallis, that long ago carried water into Gale Crater and created the alluvial fan so clearly seen from the images taken by the spacecraft orbiting Mars. On the other side of the landing area, Mt. Sharp rises up nearly 18,000 feet. These features drew us to this landing site. Now that we are there, we're hoping to understand how has that mountain has geologically interacted with the sediment carried down by the river? Was there any volcanic activity in the area? These are all things we hope to understand better as we continue to explore Gale Crater.

Curiosity went to Mars knowing a lot more about the planet than previous missions. Her scientific instruments and experiments were informed by the knowledge we gained from the landers, orbiters and rovers that preceded her. But she is well equipped and capable of answering many more questions than the previous missions. Through her, we will increase our knowledge of the red planet and better know its history.

Another topic of discussion the scientists took up at the meeting at Caltech was trying to understand the geology at Curiosity's current location in Yellow Knife Bay. She is parked here to do her first drilling activities. As she drove around this region looking for a place to drill, we obtained many images of the area that surprised us and generated new scientific questions to answer. The first drill hole exposed gray rock and drill tailings and gave us a glimpse into what lies beneath the red surface. But Curiosity won't be able to drill deeper than 5-6 centimeters into the surface to explore it further. The scientists must rely on observations from the surface to develop an understanding of what lies further below. So once again, more questions have been created by Curiosity as she brings us to new areas of Mars.

Part 1:

For two days in February, 150 scientists gathered in an auditorium at Caltech in Pasedena, CA to collectively discuss the data obtained during the first part of the mission, the interpretation of these data and to deliberate about the next places we want to explore with Curiosity.

As the scientists convened, one topic of discussion was the synthesis of all the data from Rocknest, the place where Curiosity first scooped sand. Putting together the photographic, chemical and mineralogical observations, they are seeking to understand the geological processes that formed the soil. Ideas were proposed, evidence from Earth analogs were presented to support or refute the ideas. More hypotheses were offered. More data from Mars was presented. And so the process of science goes. . .

Curiosity is answering some questions, and she is surprising us with more questions to explore. So onward we go, seeking to understand the history of Mars through the current conditions we observe.

On February 6, the MSL team got confirmation of the successful mini-drill activity, which drilled a 2 cm hole into a vein bearing rock called "John Klein." The drill cuttings show that the interior of this rock differs in color from the exterior, which has been exposed to oxidizing Martian conditions. The full drill activity will drill deeper into the rock, which is thought to have formed during wetter, and possibly more habitable climate conditions. The color difference is really interesting between the drilled rock and the rock exterior. It reminds us that we've barely "scratched the surface" and that Mars may be holding many surprises for us! SAM is anxiously awaiting the delivery of some of the cuttings from the drilling, so that we can understand how this type of rock formed on Mars. Back at Goddard, we are all preparing for the activity in which SAM will heat up powdered rock from the drill cuttings and look at what gas species are generated and whether there are organic molecules preserved in the rock. So many questions! Will the data be similar to what we found at the Rocknest sand pile? Or will Mars have more surprises up its sleeve? What will the measurements made by CheMin tell us about the mineralogy? We'll find out in a week or two, so stay tuned!

SAM has been on Mars for 175 days. The science team is busy poring over the data from experiments we have already done to help us to understand the chemical characteristics of the martian atmosphere as well as the dust and fine sediment particles that we studied at the end of last year. Our technical team is working hard to prepare us for our upcoming experiments by writing the scripts that give SAM instructions for how to do experiments and then testing the instructions on our test-bed SAM here on Earth at Goddard Space Flight Center. The Earthbound SAM is almost exactly like the SAM in Curiosity, and it is enclosed in a special chamber that simulates the martian environment. We use this test-bed so that we can better predict how SAM on Mars will behave during the various experiments it conducts for us.

Soon Curiosity will begin investigating rocks by drilling inside them, powdering samples of the rock interior, and delivering the samples to SAM and CheMin for analysis. After this first drilling campaign is accomplished, Curiosity will embark upon its martian mountain climbing expedition up Mt. Sharp.

SAM, which is a portable chemistry lab tucked inside the Curiosity rover, examines the chemistry of samples it ingests, checking particularly for chemistry relevant to whether an environment can support or could have supported life. Learn more about how SAM processes a sample by watching this video!

http://www.nasa.gov/multimedia/videogallery/index.html?media_id=156253821