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Reentry radiation is one of the key phenomena to take into account while designing an Entry Descent and Landing (EDL) phase for sample return and some gas/ice giants’ missions. In the case of an ablative thermal protective system (TPS), the physicochemical processes involved produce a large amount of dust and phenolic gases that can obstruct the optical path. The QubeSat for Atmospheric Research and Measurement on Ablation mission (5.2 kg CubeSat launched in December 2019) gave a low-cost opportunity to develop a dedicated payload named “Imbedded Nano-platform-size Emission Spectrometer” (INES) to study the radiation of a reentry plasma in the presence of an ablative heatshield (Cork P50 from Amorim™). The payload is able to measure both radiation and thickness evolution of the TPS at the same location. The paper presents a passive method to prevent any contamination of the optical path from the ablative TPS to be able to measure radiation for a wide range of mission profiles and heatshield locations.

In this article, a self-reconfiguring OrigamiSat concept is presented. The reconfiguration of the proposed OrigamiSat is triggered by combining the effect of 4D material (i.e. origami’s edges) and changes in the local surface optical properties (i.e., origami’s facets) to harness the solar radiation pressure acceleration. The proposed OrigamiSat uses the principle of solar sailing to enhance the effect of the Sun radiation to generate momentum on the Aluminised Kapton (Al-Kapton) origami surface by transitioning from mirror-like to diffusely reflecting optical properties of each individual facet. Numerical simulations have demonstrated that local changes in the optical properties can trigger reconfiguration. A minimum of 1-m edge size facet is required for a thick-origami to generate enough forces from the Sun radiation. The thick-origami pattern is 3D-printed directly on a thin Al-Kapton film (the solar sail substrate which is highly reflective). An elastic filament (thermoplastic polyurethane TPU) showed best performance when printing directly on the Al-Kapton and the Acrylonitrile Butadiene Styrene with carbon fiber reinforcement (ABS/cc) is added to augment the origami mechanical properties. The 4D material (shape memory polymer) is integrated only at specific edges to achieve self-deployment by applying heat. Two different folding mechanisms were studied: 1) the cartilage-like, where the hinge is made combining the TPU and the 4D material which make the mounts or valleys fully stretchable, and 2) the mechanical hinge, where simple hinges are made solely of ABS/cc. Numerical simulations have demonstrated that the cartilage-like hinge is the most suitable design for light-weight reconfigurable OrigamiSat when using the solar radiation pressure acceleration. We have used build-in electric board to heat up the 4D material and trigger the folding. We envisage embedding the heat wire within the 4D hinge in the future.

Quantifying the thermal response of a heat shield is a key step in the design of a spacecraft to ensure its survivability during atmospheric entry. Recession and swelling of the thermal protection material have a drastic effect on both the heat transfer within the vehicle and aerothermodynamic transients. Postflight analysis of reentry can be achieved after recovery on Earth, but it is more difficult for entries on other bodies of the solar system. A dedicated instrumentation is necessary to understand the evolution of the thermal protection material thickness during flight. This paper investigates the current limitations of the available measurement techniques. A low-mass passive solution is proposed to measure with high accuracy the phenomena of recession and swelling. The QubeSat for Aerothermodynamic Research and Measurements on Ablation (QARMAN) CubeSat mission provides a flight opportunity to develop a dedicated payload to quantify the recession and swelling of an ablative heat shield made of P50 cork from AmorimTM. In addition, this payload allows us to study the radiation of a reentry plasma in the presence of ablation products through the same optical path. The performance of the measurement technique and the integration of the instrument are discussed for the QARMAN platform, demonstrating its applicability to a space mission.

A mission scenario is proposed, where a large number of centimeter-scale femto-spacecraft are dispersed from a CubeSat piggyback payload on a future Mars mission. This swarm would deliver real-time massively parallel sensing throughout entry, descent, and landing with in-orbit measurements, atmospheric characterization during descent, and even surface science upon landing. Because few entry profiles exist at present for the in situ atmospheric modeling of Mars, a ChipSat swarm offers a promising tool for cost-effective atmospheric characterization that could lower risks for ongoing Mars exploration programs.

Future space ventures will likely require exploitation of near-Earth asteroid resources. Moreover, it can be envisaged that asteroids may host habitats in their interiors. In fact, a cavern inside an asteroid would be a natural radiation shield against cosmic radiation and may also serve as a confined environment for storage of mined material such as water ice or other processed volatiles such as propellants. To this end, this paper proposes to leverage the asteroid rotational self-energy to remove material from the asteroid interiors and create a spherical cavern, by means of the orbital siphon concept. The siphon is a chain of tether-connected payload masses (the asteroid material), which exploits the rotation of the asteroid for the delivery of mass from the asteroid to escape. Under certain conditions the siphon can be initiated to ensure self-sustained flow of mass from the asteroid to escape. A net orbital siphon effect is generated by connecting new payloads at the bottom of the chain while releasing the upper payloads. Key parameters are discussed, such as the required siphon dimension and the maximum size of the internal cavity that can be excavated, as a function of the asteroid rotational period. Moreover, assuming elastic material behaviour, a closed-form expression for the stress tensor is found and a failure criterion is used to identify regions in the asteroid interiors subjected to the larger stresses. It is shown that the conditions for failure are relaxed as the radius of the internal void increases.

International audience; We present a radiative heat flux probe capable of directly accessing a radiative boundary layer around an ablative sample. Unlike previous approaches that have suffered from pollution of the optical system by ablative species, our probe utilizes a system for preventing contamination of the optical system. We are therefore able to make measurements over a long period of time during testing in a plasma torch facility. The probe operates on a battery-powered system and can therefore be installed in facilities without optical access. It is designed for use under a wide variety of conditions within ground test facilities. Prototype tests of the probe were performed in our 50 kW plasma torch facility to study an equilibrium air flow around an ablative CBCF turning wedge and flat surface samples. Further tests of the probe were performed in the much larger plasmatron facility at VKI to demonstrate probe functionality.