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Nooks and crannies

ESP_035164_1655_0.575xA piece of Mars: This 521×391 m (1709×1283 ft) scene shows a rocky plain with many small impact craters (the bigger ones are ~45 m, or 148 ft across). Dark rippled sand fills the floors of the craters. Why? Once it blows in, it’s hard for the sand to get out. It gets caught in the nooks and crannies of the terrain. The same way it gets caught in your bathing suit and towel at the beach. (ESP_035164_1655, NASA/JPL/Univ. of Arizona)

The orbit of the exoplanet Beta Pictoris b – The first peer-reviewed article with GPI

Following our very successful first light observing runs in late 2013, the first publication based on Gemini Planet Imager observations is now complete!  It has been accepted for publication in the Proceedings of the National Academy of Sciencesas part of a special issue on exoplanets, and is now available on Astro-ph. We report in this publication the performance of the Gemini Planet Imager based on the first light tests. The first scientific result demonstrates that right from the start, GPI has been performing well enough to yield new insights into exoplanets: Our astrometric observations from November 2013  gave us important new information on the orbit of the planet Beta Pictoris b.

Screen shot 2014-04-03 at 5.14.44 PM (more…)

When Mars gets weird

ESP_025126_2640_1.0xA piece of Mars: Mars can be a strange place. This is actually a sand dune on Mars not far from the north pole. Here it’s imaged in the springtime when the dunes are still covered in  bright CO2 frost, which is in turn overlain by yellowish dust that has fallen out of the atmosphere. The dark patch is a spot where the sunlight has penetrated the ice cover enough to allow some defrosting to begin — the dark line in the middle is close to the true color of ice-free sand. (HiRISE ESP_025126_2640, NASA/JPL/Univ. of Arizona)

Surprising discovery: a ring around an asteroid

Some may say that our universe is full of beauty, others argue that it is our solar system that surprises us the most, but ultimately I will say that it is the world of small solar system bodies which is strikingly full of diversity. Today’s announcement of the discovery of rings around the Centaur Chariklo by an international team of astronomers is a vivid proof that small solar system bodies have not yet revealed all their secrets.



The millipede, rewritten

ESP_034942_1615_1.0xA piece of Mars: Looks like a millipede, doesn’t it? It’s something much larger and much less poisonous. It’s an ancient dune (or maybe a ripple) on Mars, that once stretched ~285 m (935 ft) from lower left to middle right. Since then it’s been nearly rewritten twice. The first time, a different wind direction made smaller ripples (the millipede’s “feet”) that nearly erased the original shape. The second time, a cluster of craters formed, punching holes in the millipede. Maybe it was martian pest control. (HiIRSE ESP_034942_1615, NASA/JPL/Univ. of Arizona).

ICE Spacecraft Signal Detection from the Allen Telescope Array

Jon Richards, The SETI Institute


The ICE spacecraft (see below) has recently approached Earth close enough to be detectable at the Allen Telescope Array (ATA). We have successfully detected the ICE spacecraft carrier signal using the SonATA (SETI on the ATA) signal detection equipment and will share the details here.

icee-nasa-100x128The technical community has been all abuzz about the return of the ICE spacecraft, formerly named the International Earth-Sun Explorer-3 (ISEE-3). It was launched in 1978 to study Earth’s magnetosphere and its interaction with the solar wind. The ICE spacecraft has been far away and out of contact for a long time and it is now quickly approaching earth once again. NASA has said it no longer has the equipment to communicate with the spacecraft. Radio enthusiasts around the world are trying to figure out a way to contact it and tell it to start dumping any data it may have gathered. The Bochum Observatory in Germany has been able to detect the ICE spacecraft with their 20 meter dish. Others are sure to follow.

Why We Observe Spacecraft

The Center for SETI Research at The SETI Institute operates a SETI signal detection program using the Allen Telescope Array located at the Hat Creek Radio Observatory, near Lassen Volcanic National Park in Northern California. For 12 hours every day, various stars, and now exoplanets discovered by the Kepler Mission and groundbased telescopes, are observed in an effort to detect any radio signal between 1 GHz and 10 GHz that may be from an extraterrestrial technological civilization.

On a regular basis we validate our system by pointing the 42 dishes of our telescope towards a known spacecraft to test if the system automatically detects a signal. If the signal is detected then we know the system is functioning properly. We like to observe a spacecraft that has weak signals and we commonly use Voyager1 which is very weak. Recently we have added the ICE spacecraft to the list of spacecraft we observe.


On March 10, 2014 we pointed towards the ICE spacecraft, tuned to its carrier signal frequency of 2217.5 MHz, and let the system do its thing. The ICE spacecraft signal was immediately detected. It was very weak, but strong enough for our SETI detector to recognize easily.


Signal Report

Frequency: 2217.519941667 MHz
Drift Rate: -0.17 Hz/sec
Signal width: 5.56 Hz

The system creates these images called “waterfall” plots with time on the y axis, frequency on the x axis. This representation allows us to readily see signals as lines or other shapes depending on the characteristics of the signal. You can see the ICE spacecraft signal as a fuzzy line, easier to see if you squint. The fuzziness may be evidence of oscillator degradation or of possible data transmission. The displacement away from 2217.5 MHz is the result of a Doppler shift due to the motion of the spacecraft relative to the array. The slope of the detected signal is a ‘Doppler drift’ due to relative acceleration between the spacecraft and Earth, as our planet rotates.

On March 14, 2014 we were able to detect the ICE spacecraft again

icee3-signal-mar-14-2014Signal Report

Frequency: 2217.520738889 MHz
Drift Rate: -0.09 Hz/sec
Signal width: 5.56 Hz

Future Detections

We will be using the detection of the ICE spacecraft as a system test for at least the next year, or until it becomes too weak for us to detect.

The ICE spacecraft is now just over 0.3 AU from Earth (about 45 million km). It is approaching Earth and will be closest on August 09, 2014. At closest approach the signal should be 10,000 times stronger than it is now.


Here is an zoom-in of the closest approach, this time with distance in km.


More Info



Ribbons on Mars


A piece of Mars: Bet you didn’t know there were ribbons on Mars. Long, sweeping, velvety lines, delicately frayed at the ends. These are actually ancient ripples, formed by a wind blowing from right to left. Stripes on the ripples and on the ground between them show the ancient ripple interiors, exposed by erosion. The long ripple in left center is 175 m (574 ft) long. (HiRISE ESP_016136_1525, NASA/JPL/Univ. of Arizona)

Lighting effects

ESP_034922_1385_1.0xA piece of Mars: It’s winter in the southern hemisphere, and dunes like these are covered in bright white CO2 frost. The sun is near the horizon (shining from the top of the image), so it creates stark shadows. That can make doing science tough, but it’s the best way to show off the beauty of the dunes. Can you tell which way is up here, which way is down, and when you’re looking at a inherent change in the surface color vs. sun and shadows? (ESP_034922_1385, NASA/JPL/Univ. of Arizona)


ESP_034909_1755_0.5xA piece of Mars: What is this big swoosh? It’s a big dark dune. The dark/light striping across it is found in all of the dunes in this area, but what is it? We’re probably seeing the inside of the dune: the wind may so strong here that it erodes the highest point of the dune, showing off the interior structure. (HiRISE ESP_034909_1744, NASA/JPL/Univ. of Arizona)

There’s ripples and then there’s ripples

ESP_034801_1300_1.0xA piece of Mars: On the floor of a crater in the southern midlatitudes, there’s a field of ripples. But wait, there are big ones that are very sinuous and small ones that are not. Why? Both are ripples, but they’re different kinds of ripples. The smaller ones (~3 m, or ~10 ft) are probably made entirely of sand, while the larger ones (~15 m, or 50 ft) are older and they’re probably made of a mixture of different grain sizes. (ESP_034801_1300, NASA/JPL/Univ. of Arizona).