kottke.org posts about Mars
Unlike the Earth, Mars and the Moon don't have strong directional magnetic fields, which means traditional compasses don't work. So how did the Apollo rovers and current Mars rovers navigate their way around? By using manually set directional gyroscope and wheel odometers.
While current un-crewed rovers don't have to return to the comfort of a lunar module, some aspects of the Apollo systems live on in their design. Four U.S. Martian rovers have used wheel odometers that account for slippage to calculate distance traveled. They've also employed gyroscopes (in the form of an inertial measurement units) to determine heading and pitch/roll information.
One of the fun things about reading The Martian is you get to learn a little bit about this sort of thing. Here's a passage about navigation on Mars where astronaut Mark Watney is trying to get to a landmark several days' drive away.
Navigation is tricky.
The Hab's nav beacon only reaches 40 kilometers, so it's useless to me out here. I knew that'd be an issue when I was planning this little road trip, so I came up with a brilliant plan that didn't work.
The computer has detailed maps, so I figured I could navigate by landmarks. I was wrong. Turns out you can't navigate by landmarks if you can't find any god damned landmarks.
Our landing site is at the delta of a long-gone river . NASA chose it because if there are any microscopic fossils to be had, it's a good place to look. Also, the water would have dragged rock and soil samples from thousands of kilometers away. With some digging, we could get a broad geological history.
That's great for science, but it means the Hab's in a featureless wasteland.
I considered making a compass. The rover has plenty of electricity, and the med kit has a needle. Only one problem: Mars doesn't have a magnetic field.
So I navigate by Phobos. It whips around Mars so fast it actually rises and sets twice a day, running west to east. It isn't the most accurate system, but it works.
I wonder why the rovers in the story weren't outfitted with directional gyroscopes and wheel odometers? (See also the operations manual for the lunar rovers.) (via @JaredCrookston)
Whilst roving about Mars, Curiosity has slowly but surely racked up evidence for a past Mars that was warm, wet, and possibly habitable.
John P. Grotzinger of Caltech, the project scientist for the mission, reported at a news conference on Monday that the rover's yearlong trek to Mount Sharp provided strong new evidence that Gale Crater had large lakes, rivers and deltas, on and off, for millions to tens of millions of years. The geology shows that even when the surface water dried up, plenty of water would have remained underground, he said.
Moreover, the team concluded, numerous deltalike and lakelike formations detected by orbiting satellites are almost certainly the dried remains of substantial ancient lakes and deltas. None of this proves that life existed on the planet, but the case for an early Mars that was ripe and ready for life has grown stronger.
"As a science team, Mars is looking very attractive to us as a habitable planet," Dr. Grotzinger said in an interview. "Not just sections of Gale Crater and not just a handful of locations, but at different times around the globe."
See also the interactive 28 Months on Mars.
Update: And right on cue, Curiosity has recorded a two-month-long methane burst on Mars. One explanation for the methane is that it's a waste product of living organisms.
The presence of methane is significant because the gas cannot exist for long. Calculations indicate that sunlight and chemical reactions in the Martian atmosphere would break up the molecules within a few hundred years, so any methane there now must have been created recently.
It could have been created by a geological process known as serpentinization, which requires both heat and liquid water. Or it could be a product of life in the form of microbes known as methanogens, which release methane as a waste product.
Even if the explanation for the methane turns out to be geological, the hydrothermal systems would still be prime locations to search for signs of life.
Update: And now Curiosity has found "biologically useful nitrogen" on Mars.
There is no evidence to suggest that the fixed nitrogen molecules found by the team were created by life. The surface of Mars is inhospitable for known forms of life. Instead, the team thinks the nitrates are ancient, and likely came from non-biological processes like meteorite impacts and lightning in Mars' distant past.
Features resembling dry riverbeds and the discovery of minerals that form only in the presence of liquid water suggest that Mars was more hospitable in the remote past. The Curiosity team has found evidence that other ingredients needed for life, such as liquid water and organic matter, were present on Mars at the Curiosity site in Gale Crater billions of years ago.
"Finding a biochemically accessible form of nitrogen is more support for the ancient Martian environment at Gale Crater being habitable," said Jennifer Stern of NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Update: The analysis of a year of weather and soil data collected by Curiosity indicates that a small amount of liquid water could exist below the surface of Mars.
Martian weather and soil conditions that NASA's Curiosity rover has measured, together with a type of salt found in Martian soil, could put liquid brine in the soil at night.
Perchlorate identified in Martian soil by the Curiosity mission, and previously by NASA's Phoenix Mars Lander mission, has properties of absorbing water vapor from the atmosphere and lowering the freezing temperature of water. This has been proposed for years as a mechanism for possible existence of transient liquid brines at higher latitudes on modern Mars, despite the Red Planet's cold and dry conditions.
New calculations were based on more than a full Mars year of temperature and humidity measurements by Curiosity. They indicate that conditions at the rover's near-equatorial location were favorable for small quantities of brine to form during some nights throughout the year, drying out again after sunrise. Conditions should be even more favorable at higher latitudes, where colder temperatures and more water vapor can result in higher relative humidity more often.
The Guardian and other media outlets have translated this news into Nasa's Curiosity rover finds water below surface of Mars even though NASA's release clearly states "we have not detected brines". Come on, guys.
A weight-loss doctor from Indiana owns a surprising number of the world's known meteorites, including about 2/3s of an unusual Martian meteorite called Black Beauty, which is valued at more than $10,000 per gram.
There is one diva in particular that I'm here to pay homage to: Black Beauty, a shiny, scaly-skinned, 4.4-billion-year-old rock from Mars. It began its journey to Earth more than 5 million years ago, about the time humans and chimpanzees were splitting from a common ancestor. That is when an asteroid struck Mars, catapulting the rock into space. Sometime in the last thousand years or so, orbital mechanics and gravity delivered the wandering rock to Earth. Surviving an incendiary plunge through the atmosphere, it landed in more than a dozen pieces in the western Sahara. There the fragments sat, untouched except by wind and sand. Finally, a nomad plucked a piece from the dunes. After passing through the hands of several Moroccan middlemen, the first piece wound up in Piatek's hands in 2011. He would acquire nine more.
Black Beauty has since set the collecting world on fire, reaching values of more than $10,000 per gram. (Gold trades for $40 per gram.) The price is in no small part due to the parade of scientific discoveries emerging from the rock's jumbled-up guts. It is the oldest rock from Mars and chock-full of the planet's primordial water. Most intriguing of all, it appears to be the first martian meteorite made of sediment, deposited by wind or water. That makes Black Beauty not only a cosmic blessing-sedimentary rocks are fragile and thought unlikely to survive interplanetary launches-but also a boon for astrobiologists. "If you're going to look for life, you want a sedimentary rock," says Munir Humayun, a meteoriticist at Florida State University in Tallahassee who led a study that last year pinpointed the rock's age.
It can be difficult to understand how large (or small) astronomical objects are, so here are some handy comparisons to things on Earth. Here's the size of Mars compared to the United States & Canada:
And here's a neutron star nestled next to Liverpool on the northwest coast of England:
A neutron star also crams in over 1.5 times the mass of the Sun into a tiny ball maybe not much bigger than your daily commute to work, and the Sun is huge (see the size of the Sun later). So this thing is incredibly dense, so dense in fact that just a tea spoon of it would weigh over a billion tonnes, and if you could stand on its surface you'd feel the gravitational pull of 200 billion times that of our planet...not that you'd ever survive it of course.
If there wasn't life on Mars before, there might be now. Before NASA sent Curiosity to Mars, it was thoroughly cleaned of all traces of contaminants. But swabs of rover's surfaces taken before it was sent to Mars have revealed 377 different strains of bacteria that potentially could have made the trip. Some of them may have even survived.
A study that identified 377 strains found that a surprising number resist extreme temperatures and damage caused by ultraviolet-C radiation, the most potentially harmful type. The results, presented today at the annual meeting of the American Society for Microbiology, are a first step towards elucidating how certain bacteria might survive decontamination and space flight.
Great article by Burkhard Bilger about NASA's Curiosity mission to Mars.
The search for life on Mars is now in its sixth decade. Forty spacecraft have been sent there, and not one has found a single fossil or living thing. The closer we look, the more hostile the planet seems: parched and frozen in every season, its atmosphere inert and murderously thin, its surface scoured by solar winds. By the time Earth took its first breath three billion years ago, geologists now believe, Mars had been suffocating for a billion years. The air had thinned and rivers evaporated; dust storms swept up and ice caps seized what was left of the water. The Great Desiccation Event, as it's sometimes called, is even more of a mystery than the Great Oxygenation on Earth. We know only this: one planet lived and the other died. One turned green, the other red.
Perfect read if you've been curious about what Curiosity is up to on Mars but needed something a bit more narrative than the mission home page or Wikipedia page to guide you. Also features the phrase "a self-eating watermelon of despair", so there's that. Oh, and here's the Seven Minutes of Terror video referred to in the story.
Earlier this month, the Curiosity rover photographed a dry stream bed on the surface of Mars.
That's the Mars river bed on the left and an Earth river bed on the right. Note the flat smooth rocks in the Mars pic. Pretty cool.
From Our City, Our Story, the story of a Rockford, Illinois gear factory that made all of the gears for the Mars Curiosity rover.
What might be more remarkable than creating crucial equipment destined for Mars? For a second time? Well, creating a thriving motivated company culture with a team of career employees -- the kind who lie in bed at night thinking, "what can I do in the morning when I get there?" The kind who take on responsibility, impose their own high standards and like Amy Sovina, have the "mindset something I touched is now on the surface of Mars."
I would love to have seen a live feed of these gear shop employees watching the landing.
The main imaging cameras on the Mars Curiosity rover have only 2-megapixel sensors with 8 GB of flash memory -- compare that to a maxed-out iPhone 4S with an 8-megapixel sensor and 64 GB of flash memory (not to mention 30-fps 1080p video). Planning timeframes and communications bandwidth contributed to the chosen camera size.
'There's a popular belief that projects like this are going to be very advanced but there are things that mitigate against that. These designs were proposed in 2004, and you don't get to propose one specification and then go off and develop something else. 2MP with 8GB of flash [memory] didn't sound too bad in 2004. But it doesn't compare well to what you get in an iPhone today.'
The cameras were also supposed to be outfitted with zoom lenses but that part of the project was scrapped.
On Twitter right now, Neil deGrasse Tyson is imagining how various Olympic events would work on Mars.
Women's Beach Volleyball on Mars: No protective ozone layer there. Solar UV would irradiate all exposed legs, buns, & tummies
Gymnastics: On Mars, with only 38% of Earth's gravity, the Vault & other spring-assisted leaps would resemble circus cannons.
The rest of you can have your Olympics, but the early August event I'm most looking forward to is the arrival on Mars of the Curiosity rover. But NASA has had some problems in the past delivering payloads to Mars, so this is going to be somewhat of a nail-biter. If you haven't seen it, Curiosity's Seven Minutes of Terror is well worth watching to see the logistical challenge of getting the rover down to the surface.
Curiosity will hopefully land on the surface on Aug 6 at about 1:30 am ET.
On a recent pass, the Mars Reconnaissance Orbiter caught this dust devil dancing its way across the surface of Mars.
The active dust devil displays a delicate arc produced by a westerly breeze partway up its height. The dust plume is about 30 yards or meters in diameter.
The image was taken during the time of Martian year when that planet is farthest from the sun. Just as on Earth, winds on Mars are powered by solar heating. Exposure to the sun's rays declines during this season, yet even now, dust devils act relentlessly to clean the surface of freshly deposited dust, a little at a time.
Dust devils occur on Earth as well as on Mars. They are spinning columns of air, made visible by the dust they pull off the ground. Unlike a tornado, a dust devil typically forms on a clear day when the ground is heated by the sun, warming the air just above the ground. As heated air near the surface rises quickly through a small pocket of cooler air above it, the air may begin to rotate, if conditions are just right.
From late last week, news that NASA's Mars Reconnaissance Orbiter has found possible evidence that there's flowing water on Mars.
Dark, finger-like features appear and extend down some Martian slopes during late spring through summer, fade in winter, and return during the next spring. Repeated observations have tracked the seasonal changes in these recurring features on several steep slopes in the middle latitudes of Mars' southern hemisphere.
"The best explanation for these observations so far is the flow of briny water," said Alfred McEwen of the University of Arizona, Tucson. McEwen is the principal investigator for the orbiter's High Resolution Imaging Science Experiment (HiRISE) and lead author of a report about the recurring flows published in Thursday's edition of the journal Science.
One of the better lists out there: the top astronomy photos of the year. From the list, this is a more detailed view of the Martian landscape than we're used to seeing:
My personal favorite, the photos taken by the LRO of Apollo 11's landing site, made the list as well.
Not so fast. Not sure how I missed this last week, but scientists have discovered large quantities of methane in Mars' atmosphere, and indication that the planet is active "geologically or biologically".
The origin of methane could either be geologic where water reacts with hot rock and produces methane gas which escapes through pores in the planet's surface in a process called serpentinization. Or it could be evidence of biology under the surface, where the methane generated by microbes could accumulate and then escape through the rocks.
Those plucky Mars rovers are still going. Their planned roving time was three months but now more than four years in, NASA is sending Opportunity off on a two-year trek to visit a large crater.
The mission team estimates Opportunity may be able to travel about 100m per day. But even at that pace, the journey could take two years. The rover will stop to study rocks on the way, and in winter months it cannot move because there is not enough sunlight to provide sufficient power for driving.
Water on Mars: confirmed.
Laboratory tests aboard NASA's Phoenix Mars Lander have identified water in a soil sample. The lander's robotic arm delivered the sample Wednesday to an instrument that identifies vapors produced by the heating of samples.
The lander itself added, on Twitter, "FTW!"
Scientists think that Mars' alkaline soil might be able to grow asparagus.
Although he said further tests would have to be conducted, Mr Kounaves said the soil seemed "very friendly... there is nothing about it that is toxic," he said. "It is the type of soil you would probably have in your back yard -- you know, alkaline. You might be able to grow asparagus in it really well."
About 2 hours ago, the Mars Phoenix rover twittered that it had found evidence of ice on Mars.
Are you ready to celebrate? Well, get ready: We have ICE!!!!! Yes, ICE, *WATER ICE* on Mars! w00t!!! Best day ever!!
The Mars rover said "w00t". Here's the w00t-less press release and the associated images that show the ice sublimating from the surface over the last four days.
Budget cuts at NASA means that one of the two Mars rovers will be shut down, even though it's still doing useful science.
Besides resting Spirit, scientists also likely will have to reduce exploration by Opportunity, which is probing a large crater near the equator. Instead of sending up commands to Opportunity every day to drive or explore a rock, its activities may be limited to every other day, said John Callas, the Mars Exploration Rover project manager at JPL.
The rovers were originally deployed for three-month missions but have operated for more than four years.
Update: NASA decided not to go through with Mars rover budget cuts. (thx, jeff)
High silica content of Martian soil is yet another indicator of past water on Mars. "The fact that we found something this new and different after nearly 1,200 days on Mars makes it even more remarkable."
Using ground penetrating radar, NASA has discovered an ice deposit at Mars' south pole so large that if melted, it would cover the entire planet under 30 feet of water.
Middle school students in Indiana and Australia are building edible moon rovers, with the idea that if you're going to ship a car to the moon or Mars, why not have it be edible when you get there?