It´s been a couple of weeks since we last wrote. Here is an update of what has happened in the project so far.
Last week we got the ADC card done. It is fairly dense, as can be seen in the picture below:
We have also done some tests in vacuum to see if the offset we’ve been having is due to static charging of the rotor when rotating in air. The result was a slightly lower offset (by about 10%), indicating that friction charging is not the main culprit. We have some other ideas, more on this in a later post.
We had a new rotor made in stainless steel. The reason is to try to avoid static charges sitting on the rotor, since aluminium oxide is an insulator. The hope is that a stainless rotor will prevent this, and so is part of our ongoing work with improving grounding.
One morning we also had a visit from SVT (Swedish Television) in our lab. They shot a short report for the evening news. You can read their story here (in Swedish).
On Thursday this week some of the students from the Umeå Lunar Venture crew are flying to Gothenburg to attend the Fysikdagarna conference at Chalmers University of Technology. Preparations for the trip are at full speed! We will write about the experience in a later post. Remember to subscribe via RSS and follow our Instagram and Facebook accounts for instant updates!
This week has gone by really fast maybe because it has been really busy and a we have had a lot to think about. Except being in the lab working on the instrument, a big project like this demands a lot of desk work. We have a lot of exciting events in the near future that claims some planning and organization, we will tell you more about them when it is getting closer.
This week we got new sensor amplifier cards plus some much-awaited instrument amplifiers with pin controllable gain (AD8253). With maximum amplification we get a nice, strong 600 mV signal for a field strength of around 300 V/m. With a reference voltage of 2.5 V and ADC noise around 5.5 µV (ADS1274) this means we should be able to measure fields up to 1.25 MV/m down to 2.75 mV/m (assuming no extra noise). In other words, 8½ digits of dynamic range.
We have also started experimenting with electroplating. Electroplating is the technique of coating one metal with a thin layer of another metal on-top of the first one. Mostly it is done to give the first, often cheaper metal, better characteristics to withstand oxides, or to give it other properties such as better electric conductivity or thermal insulating capabilities.. It has been used for a long time and primarily we get in contact with it in the auto industry. The big, shiny bumpers of older American cars is chrome-plated. This has been done on-top of a cheaper metal, iron, in order to give it and rustproof coating and, of course, for the design. We on the other hand is experimenting in coating our aluminum structure with copper and in the future nickle and gold. This has two purposes. One, we know that the shutter-plate of the sensor is covered by a layer of aluminum oxide and this is acting like an insulator and builds a static charge. This in turn is giving us an offset in the data from the sensor it self. Secondly, we need to gold coat the structure for thermal reasons.
As we wrote in a earlier post we attended ForskarFredag, an EU supported international event, this Friday. The event is targeted towards a younger audience. So this week have also been much about figuring out how to explain what we do in a rather simplified way. It was actually not as easy as you may think and demanded the group to summon all of our pedagogical skills and a bit of guesswork, but eventually we came up with a demonstration about static electricity. It contained a plastic box, styrofoam packaging peanuts and a Van Der Graaf generator. The setup was designed to show what happens to the dust on the lunar surface when it gets charged by the sun during the day and the cosmic radiation during the night. The plastic box was our mini moon and had a sheet of aluminum foil in the bottom to act as a “lunar-ground”. On-top of this we had the packaging peanuts as stand-in lunar dust. To get the peanuts to levitate we took the anode of the Van Der Graaf generator an placed it above the, now charged, peanuts and let them levitate. Once they touch the anode, they dissipate their charge and fall down towards the ground and gets recharged again. It seemed pretty appreciated by the children, and also by the adults. If you are following our Instagram account (@spacesciencesweden) you may already have seen some content from the evening. We had a couple from our PR team with us, whom were filming and took a lot of photos. A summary of the event will be up on the blog soon!
On the 30th of September it is time for the European researchers night! On this date, all around Europe, there will be activities and events dedicated to research and science. The goal is to show people that science and reasearch is fun!
Here in Sweden this night goes under the common name ForskarFredag and there is plenty of events happening all around the country. The local event for our hometown Umeå is arranged by Umeå University and Umevatoriet and will be an open house event for the public to attend and get inspired by science.
We will of course be there to tell you about the Umeå Lunar Venture project and to teach you a little bit more about the moon and the electric fields that we are exploring.
We hope to see you there!
Date & time:
As we wrote before we really want to engage students in the project. This week we started with an announcement about the opportunity to be involved in the project for students interested in either technology or physics. It gladly seems like we reached out and have got response from students who are interested in joining the team and the mission. Next week we can hopefully welcome some new faces to the project and therefore make the work more efficient.
A part from that this week has overall been about developing, programming and testing.
During the summer course some of the students in the electronics team developed a motor driver circuit to power and control the motors for the fieldmill. Unfortunately they could not finish the programing of the driver circuit. This week we have started to program the drivers and see how we configure them to power the motors in the fieldmil. To do this we have used a USB to I2C adapter since the chip uses I2C. But, we had a setback when the equipment to communicate from the computer to the chip failed and we don’t know why. But it is good to get these faults now so we can trace them to their source and fix it if it has something to do with our design.
On Monday we tested a new design of the fieldmill sensor with some updates. Preliminary results show some improvements to the signals. The main difference with this new design is that we can change the shunt-resistance to measure the current from the fieldmill.
The images below show the results of running the system with 1 MOhm vs 10 MOhm. The shapes of the curves agree nicely with the theory in the literature.
A part from all of this we also have started to prepare ourself for an upcoming event next week called Forskarfredag. We will describe this further in a upcoming blog post so stay updated!
It’s been a while since we last wrote, the blog has had a small break now that the summer course has ended. However, the project is not over and from now on we will update the blog at least once a week. We will try to keep you as updated as possible. Unfortunately, we cannot share everything with you since some of the information is classified.
Right now we have been having a lot of meetings about future events and the continuation of the project. The summer course has been very helpful for the project and we feel like we want to continue the collaboration with the students of Umeå University. According to them the summer course has really taught them a lot and many of them wants to keep being involved in the project, which of course we see as a big plus!
If you’ve been attentive you might’ve noticed that the project has appeared in some media outlets here in Sweden. This is something we feel really proud about and therefore we are going to make a page on our website with all the press related material. This will make it easier to keep track of what the press has to say about the project. For now, you’ll have to settle with the links below. (swedish)
As some of you may already know, TV4 Nyheterna visited us in the beginning of August. They did a report about our current mission, Umeå Lunar Venture. So if you’re eager to know more about it and listen to some of the fantastic people working on the project, watch this: