donderdag 21 september 2017

New horizons? OSCAR:LITE project description

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Are you enthusiastic about space and technology?
Do you like challenges and team-work?
Have you ever heard about the OSCAR project?

We are now busy with preparations of its next generation experiment, OSCAR:LITE. Our focus will be the development of a more advanced diamond based magnetometer to test during a stratospheric flight in October 2018, in the framework of the REXUS/BEXUS program organized by ESA (European Space Agency), DLR (German Aerospace Center), SNSB (Swedish National Space Board).

We are putting together a core-team of highly skilled and highly motivated students. In particular, the following positions are still open:
  • Electronics responsible 
  • Mechanics responsible 
  • Software responsible 
... wanna know more? Then keep on reading! :)

Optical Sensors based on CARbon materials: Lightweight ITEration

- noting a product that is low in calories or low in any substance considered undesirable, as compared with a similar product 
- noting a version that is comparatively less extreme, bulky, complex etc., than the previous version 
- light, of little weight in proportion to bulk; of low specific gravity

What is the idea behind?
The idea is to build on top of the success of first OSCAR balloon flight and to utilize the gained experience and pass it to the next generations of students. The main goal is to promote interdisciplinarity, deepen cooperation between faculties and provide students with the unique opportunity to gain hands-on experience developing a project from the start to the end.

In the first OSCAR flight we launched an experiment focused on the degradation of organic solar cells in the stratosphere and on the construction of a prototype diamond based magnetometer with optical readout. The successful flight of the OSCAR project and the large amount of collected data served as a first confirmation that both organic-based solar cells and diamond magnetometers are suitable for aerospace applications, and suggest that further work in the field can lead to great technological advancement in the fields of energy-for-space and space-compasses. This project is going to be a successor to the diamond based magnetometer part of the OSCAR project.

With our first optical readout based prototype we revealed several limitations of this system, such as low readout speed, bulkiness, high power consumption, mechanical complexity and low long term stability caused by the optical components. Advances in field of photoelectric readout of magnetic resonance (PDMR – “the electric readout”) will allow us to fabricate a device which will overcome the aforementioned limitations, mainly reduction of mass, power consumption, complexity and will improve the sensitivity and system stability.

What are goals of this project?
Develop a miniaturized, portable and ultra sensitive diamond magnetometer based on the photoelectric readout of magnetic resonance [1] Demonstrate that the device can function as a magnetometer for aerospace applications (3d compass, device rotation, position corrections Verify device functions and limitations in near-space conditions for future use in cubeSat Measure and evaluate Earth’s magnetic field at various altitudes, compare with the data from previous flight, and publish the results (noise levels, acquisition speed, performance, …)

What is it about and how it works? (little bit of science and technology)
Optical sensors based on carbon materials offer high potential for future aerospace applications. The device under test within the OSCAR:LITE experiment is a prototype diamond magnetometer with electric readout. This technology is based on carbon materials with unique electro-magneto-optical properties. The following paragraphs will discuss the physical mechanism as well as the advantages and drawbacks of this technology.

The measurement of magnetic fields is crucial in many applications ranging from navigation to data storage. Recently, it was shown that defect color centers in synthetic diamond can be employed to detect magnetic fields with sub-picotesla resolution, opening up new possibilities in areas where high precision magnetic field measurements are required, such as navigation, quantum computing, metrology and sensing.
Figure 1: (left) Nitrogen-Vacancy (NV) center in the diamond crystal lattice (right) Zeeman splitting of NV-based magnetometer

The detection is based on nitrogen-vacancy (NV) centers which are present in the diamond crystal lattice (figure 1a). NV-based magnetometers are classically based on the optical detection of magnetic resonance (ODMR). In this technique, the NV centers are illuminated by a green laser light, promoting electrons from the ground to an excited state in the NV center. The radiative decay of these electrons (to the ground state) induces the emission of red light. The photo-luminescent (optical) transitions associated with the spin sublevels of the NV ground state present different brightness. The application of a microwave field with resonant frequency drives electrons from the |0> to the |±1> spin sublevels, and leads therefore to a drop of the luminescence intensity. The presence of an external magnetic field induces a splitting between NV |±1> spin sublevels (Zeeman effect), resulting in a splitting between the microwave resonant frequencies (Figure 1b). From this effect, it is possible to determine the magnitude of the magnetic field. This optical method was demonstrated in first OSCAR flight.

 In 2015, it was demonstrated by our research group that the magnetic resonance of NV-centers in diamond can be measured by probing the photocurrent instead of the optical read-out[1]. This direct photo-electric read-out of NV centers, called photocurrent detection of magnetic resonance (PDMR), is based on the detection of charge carriers promoted to the conduction band of diamond by two-photon ionization of NV centers. Minima are detected in the measured photocurrent at resonant microwave frequencies, due to the spin-dependent ionization dynamics of NV centers. This detection technique only requires the fabrication of electrodes on the diamond chip by standard lithography and avoids the complexity of optical detection, allowing further miniaturization of the magnetometer. By using this technique the diamond sensor serves as its own detector.

As these devices are based on diamond, they exhibit a very strong radiation hardness, which makes them well suited for aerospace applications. Furthermore, due to their size they have a very small footprint, they are stable in a very broad temperature range and possess a high dynamic range combined with higher sensitivity compared to commercially available magnetic sensors based on the Giant Magneto Resistance effect (GMR) or Flux-gates. Characteristics of the diamond based magnetometry device enable sensing of the magnetic field in 3 dimensions. Another advantage of this device is the capability of simultaneously measuring the magnetic field and the temperature. All these features emphasize the potential of a diamond magnetometer for aerospace applications

What is the concept of this experiment?
The concept of the experiment (see figure 2) is to allocate a PDMR magnetometer on a boom, sticking out of the gondola to minimize the influence from and to other experiments. The payload box with electronics, providing communication and data transmission between ground station and the magnetometer sensor, will be on board of the gondola. concept.png

Figure 2: Experiment concept layout

What is a core-team and what are the responsibilities?

The main roles of core-team are:
  • overview of the project
  • effective distribution of task and responsibilities for task finalization
  • project planning, scheduling and task execution
  • resource management and overview of task progress
  • problem solving
  • attending reviews and events

Figure 3: Preliminary mind-map of responsibilities of each core-team member 

How is it with timing and workload?

Figure 4: Time overview of critical review points in the course of the project

Gantt chart in figure 4 demonstrates the workload of the project. Green marks represent days when results of acceptance/denial of the project are received. Yellow represents standard workload and Red represents critical steps and periods of time, when the workload or severity of task(s) peaks.

For example, (2) preparation of project proposal is a very critical part for invitation to selection workshop, or (12) Integration progress review preparations are when the amount of hands-on and experiment integration is increasing, or (14) Experiment acceptance review preparations: in the first OSCAR flight this was when majority of bugs, mistakes and interferences occurred, therefore this period is marked red, also because of its severity (final review == flight ticket). Also from past experience we concluded that the majority of peaks in workload in later stages could have been reduced by proper planning, increased focus in designing and better decisions during early stages (CDR, PDR).

What is plan in next few months?

How important is this project for future?
One of the aims of this project is to verify the viability of this device to be used in a cubeSat mission. The precision of this device combined with its small footprint can provide a perfect solution for this kind of applications. For example, in satellite missions for accurate altitude determination is essential to know how the satellite is oriented in the inertial space. To do so, low Earth orbit satellites can use a magnetometer to read the magnetic field of the Earth and compare it with a geomagnetic reference field (i.e. IGRF). For this it is necessary to know the position of the spacecraft at the exact moment (GPS, laser ranging or combined). Then, by taking the reference field in that position and comparing it with magnetometer readout, a rotational matrix can be calculated. In the next step the rotational matrix is used to determine the precise orientation of the satellite.

Do you want to join us?

Do you have a question?
Contact us!

[1] E. Bourgeois, A. Jarmola, P. Siyushev, M. Gulka, J. Hruby, F. Jelezko, D. Budker & M. Nesladek, Photoelectric detection of electron spin resonance of nitrogen-vacancy centres in diamond, Nature Communications 6, 8577 (2015)

dinsdag 10 januari 2017

Wrapping it up

Where has OSCAR been?
What have we been up to?

After the launch campaign, the project is not over. Our experiment collected plenty of data, and this data needs to be analysed in order to make use of it and valorise our year-long efforts.
This tedious part of the work has already started, but it's not over yet! We have almost two hundred thousands curves to analyse for the solar cells, and a few hundred sweeps for the magnetometer.

Besides, like all projects, the documentation has to be kept up to date and accurate. Which means we have been busy issueing the last version of our Student Experiment Document, containing all final details on the flight and on the experiment.

In the meantime, since we did fly on a stratospheric balloon, we also got quite some attention from our university in the form of a UHasselt video story!
This can be viewed on our YouTube channel, together with other outreach-related videos from the past months.

donderdag 13 oktober 2016

BX23 flight day

[Photo credits of the aurora before the BX23 flight: Michael Becker]

The day BX 23 took off, we had a count down starting at 3:30 AM.
All teams gathered at the dome (massive construction where gondolas are assembled) to finalize preparations and run the usual last tests before launch.
Things are tense until the very last minute, and the four hours countdown can easily last five hours and a half.
But nobody would ever complain: we are there, and our sweat and tears of the last year are about to fly!
Less than one hour before the final lift-off, the late access team comes back, after removing the covers from our solar panels. This is the last we could see OSCAR up close before the launch.
The last full three quarters of hour, the whole bunch of the BEXUS campaign participants stayed at the entrance of the dome, super excited while they witnessed a perfectly nominal balloon inflation and lift-off.
After nearly five hours, the cut-off sequence was initiated. We managed to gather a huge amount of good data until our battery dried out, shortly before the descending.
Less than 24 hours later, we could meet our experiments again, when the recovery team brought our gondola back. You can imagine our surprise when we saw that OSCAR's frames withstood the fall (through some tree branches, even!).
More info and many more photos will follow!
For now: Thank you!
ThanX to all those who supported and helped us during this intense year of preparation! It was worth every minute of work!

donderdag 6 oktober 2016

Campaign week process

After 5 days of work, OSCAR is ready and fixed on the gondola!
The last few days have been very very tiring, with a lot of mounting and testing to do, and the occasional ghost hunt for to resolve problems that were never really there... We troubleshot so much in the last month, that we cannot believe that we do not have anything else to fix!

Make sure to keep an eye on our facebook page to follow our adventures :) In the meantime, we will take as many pictures and videos of our countdown and launch as possible! Like this we can report back soon and show you the payback of an entire year of work.

zaterdag 1 oktober 2016

Campaign week has started!

After roughly one year of work, our team has finally made it to the end!
We packed the rest of our experiment in an awesome BRAVIA 55' TV box (just to make sure airport staff will treat it as gently as possible) and got on the plane.
As soon as we landed in Kiruna, we could find again (almost) all the other teams members!
Get in for a group selfie, everyone!
Of course, first thing to do in the evening/night/early morning of our arrival is not sleep... We need to get used to heavy schedules, so: let us re-mount SAM-V3! Remember the awkwardly large magnetometer we once buried in the snow during training week? Well, he came with us once again, but needed some new tweaks, which J&J worked on till too late.

The North of Sweden looks different without the piles of snow. We left a white mass of land in February, to find a green forest! That means a whole new set of activities possible for our free time!
... but will we even have any?
For now, we are busy assembling all components back, fixing last minute changes, and trouble shooting for the last time.
Keep tuned, as we will try to share our progress as frequently as possible in between the rest of the campaign preparations!

woensdag 21 september 2016

There it goes...

OSCAR finally left UHasselt, in a very heavy and sturdy wooden box.

... bye bye, baby Aury!

See you in Kiruna!

dinsdag 20 september 2016

S.U.Z.Y. meets OSCAR

Our experiment passed its last review, and is finally ready to fly.
With this news, a lot of local news channels and science enthusiasts got really interested in us, and that's how we ended up not only on the local TV channel TV Limburg and in the national news paper Het Laatste Nieuws...

... but also tagged on Stijn Meuris' photo!

It was quite something to meet the man who sang about lovely satellite S.U.Z.Y, spinning quietly above the Earth and watching us from a distance.

Tot binnenkort, S.U.Z.Y!