Astrobio Cubesat Satellite

MEO orbit and hosting a mini laboratory payload based on lab-on chip technology.

Hosting a mini laboratory payload based on lab-on chip technology. The objective of the project is to test an automatic laboratory based on lab-on-chip technology, able to provide a highly integrated in-situ multiparameter platform that uses immunoassay tests exploiting chemiluminescence detection. 

The perform the experiment, a paper-based later flow device will be used. The paper-based support will contain:

• biomolecules immobilized in specific test areas (i.e., enzyme in experiment 3, antibody in experiment 4, see the experiment list below);
• chemicals deposited in a non-permanent fashion and in a dry form in the initial part (starting area) of the microfluidic path (e.g., luminol and potassium ferricyanide): when the reagents-delivery-system provides a volume of a reagent or sample in the liquid form to the starting area, capillary forces will capture the liquid reagents and force them to flow along the paper-based microfluidic pathway. During the flow, liquid reagents will solubilize and transport along the path the deposited reagents, thus triggering specific reactions. As photon emission signals are recorded as a result of correct experiment execution, a photosensor will always be present in correspondence of each test area to detect the chemiluminescence reaction.

The experiments will aim at evaluating:

• the functional tests of the device (delivery of reagents, mixing of chemicals, detection of emitted photons, electronics, data storage and transmission);
• the stability of chemicals and biomolecules employed in the experiment and necessary for performing bioassays (e.g., immunoassays exploiting chemiluminescence detection) in space conditions for astrobiological investigations.

The satellite included the following subsystems:

• An aluminum-based structure, fully compliant with the standard of commercial and certified CubeSat deployers, with original design, to allow housing the peculiar hermetically sealed box, and multi-layer tungsten-reisin-aluminum shielding to reduce the to-tal radiation dose collected during the mission.
• An electric power system (EPS), consisting of Li-ion battery pack recharged through triple-junction solar cells, providing electric power (3V3, 5V, 7V) to each individual load by latching current limiters.
• A passive magnetic attitude control system aimed at maximizing the exposure of solar cells to solar radiation.
• A hermetically sealed box, thermally isolated from the ABCS structure, to guarantee the nominal pressure and thermal stability required by the payload. All the following subsystems, the EPS and the pri-mary payload were installed inside the box.
• A thermal control system obtained from (i) surface finishing of the hermetically sea box and insulating materials at the interface of the box with the ABCS structure (passive control) and (ii) modulated radio beaconing and resistive heaters (active control).
• ABACUS on-board computer (OBC) managing telecommands, satellite housekeeping, payload op-erations and data handling. The OBC also imple-mented error detection, isolation and self-healing, as well as a digipeater freely accessible and widely used by amateur radio operators.
• A telecommunication system based on a single UHF transceiver and custom design deployable antenna in turnstile configuration.

ABCS was deployed by Vega-C under nominal con-ditions on July 13th 2022 at 15.27 UTC. The early bea-cons received by Australian radio amateurs confirmed that the satellite status was nominal and, since they used the graphical user interface developed by SIA and freely de-livered through AMSAT community, all the data were suddenly stored on the ABCS mission database. As scheduled, 15 minutes after the deployment the OBC commanded the automatic execution of the experiments, that were performed every 15 minutes for a total of six experiments, each one lasting 10 minutes. To date, the operational phase of the mission can be considered concluded.

Although an anomaly that occurred during the execution of the experiments did not allow the observation of chemiluminescence, that would have provided a complete validation of the payload, the system architecture made it possible to verify which components operated nominally, thus allowing the validation of the lab-on-chip technology. It is worth noting here that this achievement was made possible by a series of subsystems, constituting the satellite bus, which due to the peculiar operating conditions of the payload and the unusual features of the space environment required significant design effort. The sys-tems description and their performance are discussed in the following sections.

Analysis of flight data demonstrated that the seal of the hermetically sealed box worked perfectly throughout the mission. A leak rate of less than 10−7 mbar · l/s was recorded, corresponding to the nominal value for gas-tight sealing. Furthermore, using the ideal gas law (pV = nRT ) it was shown that pressure changes corresponded to temperature changes inside the box, providing a second evidence that no leaks occurred during the mission.

On its smaller faces, ABCS hosts two arrays of 5 cu-bic corner reflectors (CCR), integrated to perform satellite laser ranging experiments (see Figure 5). Aiming at pro-viding useful information for attitude determination from satellite laser ranging, the CCR of each array are mounted with different relative orientation, therefore providing diffferent interference pattern when illuminated by the laser.

It was known that the probability of tracking a satellite equipped with small COTS CCR in such a high orbit is quite low and no laser ranging results have been obtained in the attempts made to date. However, since ABCS will orbit the Earth for several hundred years, new attempts will be made in the future, possibly relying on more pow-erful laser stations.

• ALPHA (ARCA)
• Astrobio Cubesat (ABCS)
• CELESTA
• GreenCube
• MTCube 2
• TRISAT-R