Satellites

News: QB50 and Space Debris Conference

Yesterday was a very long and a very busy day for me – I traveled to Europe to attend the 7th European Conference on Space Debris and we had two satellites launch into space as part of the QB50 mission.

QB50 is a European led mission that has about 35 CubeSats that have been launched to the international space station (ISS).  Each of the satellites, which are about 4 inches by 4 inches by 8 inches (like, really small), carries one of three different sensors that measure the space environment.  The Europeans provided the instrument and the launch, while each group provided the satellite.  University of Michigan build two satellites, called Atlantis and Columbia, that carry the FIPEX instrument.  FIPEX measures the atomic and molecular oxygen density in the thermosphere.  Oxygen is the main gas in the thermosphere, so, in effect, these satellites will measure the air density.  This is important for satellite orbit prediction and collision avoidance. Below is a picture of these two satellites with a bunch of the students, faculty, staff, and engineers that worked on them.

qb50_group_photo

On April 18, 2017, the satellites were taken up to the ISS on a normal resupply mission. They are in deployers called NanoRacks, which push the satellites out into space from the ISS. According to QB50 officials, this should happen in the first few weeks of May. The satellites will then turn on, deploy some drag panels, and start to communicate with the ground station at UM.  We will then command the FIPEX instrument to turn on and start to take data.

While the launch was happening, I was participating in the 7th European Conference on Space Debris.  This conference has about 350 people who are investigating all sorts of aspects of space debris: new techniques for discovering it, quantifying how much there is, and looking at ways of removing it, just to name a few.

A quick refresher on space debris: There are over 20,000 objects orbiting Earth that are about the size of a softball or larger. Since we have hundreds of active satellites, this debris cloud is a problem, since if a piece of debris hits an active satellite (or another piece of debris), it will destroy it and create even more debris. People talk about a Kessler Syndrome, which is basically where low Earth orbit becomes crowded with debris which leads to collisions, which leads to more debris, which leads to more collisions, etc.  This has the potential for running away and basically making low Earth orbit unusable.

I got to watch a talk by Kessler yesterday.  He is a retired NASA employee. Sort of cool to see such a talk.

So far, I have watched a bunch of talks on how to measure debris and some missions that are trying to raise money to remove debris.  Measuring the debris is very interesting, since you can sort of do this with a relatively inexpensive camera.  Just before sunrise and just after sunset, the ground is in darkness, but the sun is still shining on satellites. If you look up in the sky during these times, you can see this reflected light and observe the satellites. Which is pretty awesome.  If you take pictures with a camera, you can figure out the speed of the debris, which gives you its orbital characteristics and roughly how big the object is (from its brightness).  The better your camera, the smaller the debris you can see. I may try to do this with some students. It seems like a great project.

For the debris removal missions, there are a bunch of hurtles: (1) getting to space is very expensive, so it may cost so much to get the junk down, that it is not worth it; (2) rendezvousing with the debris is really hard, since it is quite difficult to automatically track and maneuver into position; (3) capturing the debris is hard, since it may be spinning and oddly shaped; and (4) deorbiting the debris is a challenge, since you have to rigidly attached the debris to some sort of thruster and then use a bunch of fuel to deorbit it.  This means that the missions are pretty expensive and have a LOT of technical hurtles to get over in order to be feasible.  But, they are pretty interesting to learn about!

 

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