DeepEarthScience

Last week, components of the TUDelft satellite tracking station were delivered. This includes a radio, amplifiers, Software Defined Radio (SDR), a GPS-based clock and other cool electronics. We are now planning the integration of all the components in the existing ground station, which is used for the data downlink and command uplink of the Delfi-C3 and Delfi-n3Xt (both student designed and built satellites currently orbiting Earth). But how does this tracking (you speak of) works? It starts with capturing and recording the communications signal of the satellite, which is transmitted continuously (if the Sun shines on the solar cells to produce energy). This is where all the fancy and complicated electronics play a role. (However, I am not an expert in this, so I will only explain the physics behind it). The high frequency (145.870 MHz) electromagnetic signal is down-converted to a signal that can be made digital, such that a computer can process it. First we put the signal throug...

It is many weeks since my last blog post, my humble apologies! I was very engaged with my work. I was teaching students the wonders of Planetary Sciences, which is a difficult task, because 80 percent of them just wants to build satellites (damn you engineerings, wanting to built stuff). However I do not complain because this year's group is really participating and some of the students even want to do some science (mate). In one of their last assignments they had to work with ballistic trajectories (calculating planetary geysers and volcanic exit velocities). This particular subject gave me inspiration for a new blog post, so there you go. Ballistic trajectories always interested the minds of many young boys (and might a say girls) and I have a great story about it, but I was always hesitant to write it in my blog. Some would say (me being one of them) that guns are bad (but can be modeled very well with ballistic trajectory theory)! Still my fascination for modeling and scie...

As a scientist, your are expected to be at the boundary of the current knowledge in your field. You should know which state-of-the-art methods are used. The newest findings should be know to you. And more importantly, you should know what is still unknown. As a PhD candidate, you are learning to become a self-sustainable researcher. Therefore, a PhD candidate should, in the end, be at the boundary of the current knowledge of his subject and maintain that knowledge. So how do you keep up with the fast expanding frontier of knowledge in your field? My trick to stay at the boundary of the current knowledge is to keep an eye on the most important journals in my field. You can do this even if you are not subscribed to the journals. Every journal has an RSS feed (I know this is an ancient tool, but it works so why don't use it), that gives information on the latest publications of the journal. Most of the cases, it releases the abstracts of the latest accepted articles. Jour...

A few weeks ago the second TUDelft satellite (Delfi-n3Xt) was successfully launched into an orbit around Earth. In space, yes! This satellite was designed and built by students of my university. However, their other 5-year-old satellite (Delfi-C3) is still flying and communicating its data towards Earth. A student, a colleague and I are using this old satellite to test our idea for a new satellite-orbit determination-project. I always like to call it: "Listening to the sound of satellites" (see previous posts).  During the launch event I was thinking that it would be cool to capture both satellites' transmission in one observation using the VHF antennas. So I ask the ground station operator (the student), if this was possible. After a few days he send me this figure: He found a day that both satellites were visible from the TUDelft ground station. The red line is the orbit track of the Delfi-n3Xt (new one). The green cross is the location of the TUDelft ground...

At the end of a week full of science, I had a touristic trip into the woodlands of Muir. Together with a geologist I met in San Francisco, I traveled to the forest with the large trees seen in the very famous bike chase scene in Star Wars on the second moon of Endor. It was a great trip and I can recommend it to anybody visiting the City of Fog. The Muir Woods are situated in a valley, where the climate is much different than the surrounding mountain lands. So a geologist and a geophysicist could not resist to climb a mountain to the top (I say mountain, but they were large hills, except when I said that the giftshop woman gave me angry eyes). We decided to follow the Hillside trail, followed by the Ben Johnson trail. These trails gave us a good view of the forest and let us examine some really nice rock outcrops of the mountain. And on one of them I found this rock: It is a greenish rock, which according to the geologist, could be serpentinite or an olivine containing r...

It all started with a delay of four hours. Being on our route for over an hour (above Scotland), the intercom of the airplane (a MD11 type of aircraft) sounded: "This is your captain speaking and I have some bad news." There was a technical problem that could not be fixed in San Francisco, so it was decided to fly back to the airport Schiphol, Amsterdam. I was just finishing my first beverage. One of my colleagues told me that he had several experiences like this with MD11 aircrafts. They are old and should be taken out of service. But for now we got a different MD11 that would take us to San Francisco. Four hours later than originally planned, we arrived in the Fog City (it was a clear day). However, at the gate after the pilot had shut down the engines, the ground personnel tried to connect the power cables such that the doors could be open. Only this was not working, so 350 already a bit weary passengers were stuck inside the aircraft. And no power means no air-conditioni...

This morning I got up earlier today to attend the Delfi-n3Xt launch event in our faculty. Delfi-n3Xt is a nano-satellite (the size of a milk carton) which is built by students and staff of our faculty. Launch events are always exciting, because you don't know what will happen. But after two stressful hours we got the confirmation, "Nano-sat number 7 successfully deployed." This was followed by some cheerful cheers. However, was it turned on? This blog started with some post about listening to satellites using the ground station on top of EWI (faculty of electronic engineering, mathematics and computer sciences). This ground station is mostly set up by a student which I assist in teaching him to track satellites. So this gives me the opportunity to get the telemetry data of the Delfi-n3Xt quite fast. It's good to be a teacher :). The next figure will show the satellite's first sounds in space: Click on the figure to get a larger view. In the bottom left...