Tag Archives: planetary science

Cubesats to the planets!

Link here. The article is a good detailed overview of the many upcoming planetary missions that are using small and relatively inexpensive cubesats as either part of their mission, or are the mission itself.

This trend also partly explains the number of new rocket companies like Rocket Lab and Firefly Space Systems that are developing small rockets aimed at launching cubesats. These companies have recognized a growing demand, and are trying to serve it. As the article notes,

Lifts are so hard to come by that the first interplanetary CubeSat — NASA’s twin INSPIRE mini-spacecraft, intended to test key technology for future missions — has been waiting for almost two years. “We still have to find a ride,” says Anthony Freeman, who manages the Innovation Foundry at NASA’s Jet Propulsion Laboratory in Pasadena, California.

Our limited understanding of the Martian climate through time

The uncertainty of science: Annual Reviews periodically publishes papers providing a detailed scientific review of the present state of knowledge in a variety of fields. They do this by collecting the papers in volumes focused on general areas of research, such as Astronomy and Astrophysics, Plant Biology, and even Sociology.

Today I received the announcement of the publication of the 44th volume of the Annual Review of Earth and Planetary Sciences, listing the volume’s table of contents. While there were many interesting papers on a variety of planetary subjects that interested me (“The climate of Titan,” “Impacts of Climate Change on the Collapse of Lowland Maya Civilization,” and “The Lakes and Seas of Titan”), one paper in particular, entitled “The climate of early Mars”, intrigued me enough after reading the abstract to download it and read it in its entirely. (As a science journalist I have free access to the full text of these papers. While the abstract is free to all, if you wish to read the full text you need to either buy it, or visit a university library that subscribes to each particular series.)

As a review I found the paper quite fascinating. It provided an excellent overview of our present understanding of Mars’s climate history, information that is especially useful to me in reporting on the results from the various Martian orbiters and rovers, as it gives me a wider context and allows me to better understand and analyze each press announcement. This in turn allows me to distinguish between a real discovery of some importance and a garbage press release that is really nothing more than a sales pitch for more funding.

The bottom line of this paper however is this: We know without doubt, based on a lot of geological evidence, that approximately 3 to 4 billion years ago liquid water existed on the Martian surface, leaving behind complex valley drainage networks similar to those created by flowing water on Earth. In addition, the data from the rovers has also found evidence, clays and other minerals, that could only have formed if water once flowed on the surface. What we don’t know is how that liquid water could have existed. The data so far does not provide any clear mechanism for warming the climate enough as well as producing a thick enough atmosphere to allow liquid water to flow. To quote the paper:

In summary, no single mechanism is currently accepted as the cause of anomalous warming events on early Mars.

The data also suggests that an ocean on Mars was unlikely, though not impossible. Instead, it appears that if any warming events occurred to produce liquid water, they were temporary and short-lived. What caused those warming events, however, remains a scientific mystery.

The paper also made clear once again the complexity of climate science, and how difficult it is to develop climate models that explain the geological evidence, not just on Mars, but on Earth as well. As the paper also noted, “Just like the climate of Earth today, the ancient climate of Mars was probably complex, with multiple factors contributing to the mean surface temperature.” And like the climate of Earth, many of those multiple factors remain uncertain and poorly understood. It will be many years before we really understand how Mars got to be the way it is.

Likely, to figure it out we will have to go there ourselves and poke around with our own hands.

Juno closing in on Jupiter

Jupiter from Juno

On Friday the Juno science team released a new image of Jupiter taken by the spacecraft from about 6.8 million miles away.

The reduced resolution image on the right is cropped but with the colors enhanced to bring out the four Galilean moons, Ganymede, Callisto, Europa, and Io. The website notes that “Juno is approaching over Jupiter’s north pole, affording the spacecraft a unique perspective on the Jovian system. Previous missions that imaged Jupiter on approach saw the system from much lower latitudes, closer to the planet’s equator.”

Rendezvous and orbital insertion happens on July 4.

To save money, NASA management has shut down a troubled program to build a more efficient plutonium power supply for its deep space missions.

To save money, NASA management has shut down a troubled program to build a more efficient plutonium power supply for its deep space missions.

The cancelled ASRGs would have generated electrical power from the expansion of gas warmed by the radioactive decay of plutonium-238. NASA says that the devices have the same power output as its current generation of Multi-Mission Radioactive Thermoelectric Generators (MMRTG) but use four times less plutonium-238, a scarce resource. One MMRTG with 4.8 kilograms of plutonium is currently powering the Curiosity rover on Mars.

The United States has less than 40 kilograms of plutonium-238 left, but the DOE restarted production this year. Green says he is confident that the DOE will be producing plutonium-238 at a rate of 1.5 kilograms per year by 2019. He says that the stockpiled plutonium-238, along with the new supply, will be enough to send another planned rover to Mars in 2020 and to complete other missions in the 2020s – without any need for the extra efficiency of the ASRGs.

The ASRG program had been a year and a half behind schedule and had had its management team replaced at one point.

Russia heads for Mars

Russia heads for Mars: a detailed look at the Phobos/Grunt sample return mission, set to launch on November 8.

I really wish the Russians good luck with this project. Not only would it herald their return to planetary science since the fall of the Soviet Union, success here would break their long string of failures to the red planet. Though their unmanned planetary program had some remarkable achievements during the Soviet era, of the 19 missions they flew to Mars in the 1960s, 1970s, and 1980s, all were failures, producing almost no useful data.

A NASA senior review of all planetary missions?

Here’s a tidbit I just spotted on the EPOXI (formerly Deep Impact) status website, buried in a November 1, 2011 update::

Meanwhile, NASA has decided that there will be a senior review of all operating planetary exploration missions. That will likely include a review of the status of the Deep Impact Flyby spacecraft to determine whether an additional extended mission should be approved. Decisions will not occur until early 2012.

Though Deep Impact is still a functioning spacecraft in orbit around the sun, up until this notice I had not heard of any plans to use it again after its flyby of Comet Hartley-2 in 2010. However, there is no reason its cameras could not be used for astronomy, though unfortunately its high resolution camera has a focus problem which prevents it from taking the sharpest images.

However, the timing of this review of planetary missions, combined with the story last week that the Obama administration might end all funding for future planetary missions, is intriguing. I wonder if they are tied together in some way. That the notice above says the decision will be made in “early 2012” — the moment when the Obama administration will unveil its 2012 federal budget recommendations — strongly suggests that they are linked.

Could that the administration be thinking it can salvage the bad press it will receive for shutting down all future planetary missions by spending a small amount on extending missions already in space? Or is this planetary review another indication that the rumors are true and the administration plans to end the planetary science program entirely?

Unfortunately, I am speculating here, without any real information. Stay tuned to find out.

A summary of Messenger’s first six months in orbit around Mercury

A summary of Messenger’s first six months in orbit around Mercury.

Though packed with lots of results, this strikes me as the most interesting discovery so far:

Orbital data reveal that Mercury’s magnetic field is offset far to the north of the planet’s center, by nearly 20% of Mercury’s radius. Relative to the planet’s size, this offset is much more than in any other planet, and accounting for it will pose a challenge to theoretical explanations of the field. . . . This finding has several implications for other aspects of Mercury, says Anderson, who co-authored several of the presentations in the MESSENGER session. “This means that the magnetic field in the southern hemisphere should be a lot weaker than it is in the north. At the north geographic pole, the magnetic field should be about 3.5 times stronger than it is at the south geographic pole.

The rover Opportunity as seen from Mars orbit

Opportunity on Endeavour Crater rim

The image to the right was taken by Mars Reconnaissance Orbiter, with the white arrow showing the Mars rover Opportunity perched on the rim of Endeavour Crater.

The rover’s scientists hope that the rocks found on the crater rim, dredged up from deep below when the crater impact occurred, will be the oldest rocks so far touched on the Martian surface, and thus give them a peek at ancient Martian geology.

Video from Dawn

NASA has released an update summarizing what scientists have found since Dawn went into orbit around Vesta in July. The video below, compiled from images Dawn has taken, gives a nice visual overview. The most interesting big feature, understated by the video, is the series of grooves that appear to encircle the asteroid’s equator. To my eye it almost looks like Vesta was once two asteroids that got merged into one, with these grooves indicating the weld point.

The direct link to the video can be found here.

Embedded video from

NASA Jet Propulsion Laboratory California Institute of Technology

The Pioneer anomaly is fading

The Pioneer anomaly is fading.

The analysis shows that the anomaly is not constant, as researchers had believed, but is decreasing with time. The finding points toward a conventional explanation of the phenomenon, most likely asymmetric radiation of heat, and against some of the more exotic proposals.

Getting closer to Vesta

close-up thumbnail

The Dawn mission team released another image today of the giant asteroid Vesta, this time taken from about 2,300 miles away. At this distance the resolution is still somewhat coarse, with the smallest visible detail about 0.43 miles in size.

To the right is a cropped section of the full image, focusing in on what appears to be a very strange geological feature, indicated by the arrows. From what I can tell, the dark meandering streak looks like a rille or flow coming out of the mound or peak near the bottom of the image. Yet, this dark meander continues directly across a crater as if it were a wind-blown dust streak.

I really have no idea what geological process created this. I also suspect that the scientists don’t quite know yet either, though I am sure they have some good theories, mostly based on the very light gravity that should exist on a world only 330 miles in diameter. As I’ve already noted, however, it is going to take them a couple of months to digest the data they are getting and come up with some reasonable conclusions. It will be fun to finally find out what they have learned.

Ethane lakes in a red haze: Titan’s uncanny moonscape

Titan’s ethane lakes in a red haze.

So far, there are no recognisable signs of organic life. That’s not surprising: by terrestrial standards, Titan is a deep freeze with surface temperatures at a chilly -180°C. Yet Titan is very much alive in the sense that its atmosphere and surface are changing before our eyes. Clouds drift through the haze and rain falls from them to erode stream-like channels draining into shallow lakes. Vast dune fields that look as if they were lifted from the Sahara sprawl along Titan’s equator, yet the dark grains resemble ground asphalt rather than sand. It is a bizarrely different world that looks eerily like home. Or as planetary scientist Ralph Lorenz puts it: “our prototype weird-world exoplanet”.

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