Uncrewed Systems Technology 046

61 Space vehicles | Insight The heat shield is 5.03 m in diameter, and will shed severe heat away from the crew module (the reusable portion of Orion) as the spacecraft returns to Earth at roughly 40,200 kph and enduring temperatures of around 2760 º C. The heat shield’s outer surface is built from 186 billets of an ablative material called Avcoat, which is an epoxy novolac resin with special additives in a fibreglass honeycomb matrix; it is a variant of the material used on the Apollo mission capsules. It is bonded to a titanium skeleton and a composite skin to enable its shape and structural support for the crew module during descent, during which the Avcoat burns off in a controlled fashion to transmit heat from the module. Furthermore, after the Orion separates from the SLS’ stages, 10 uncrewed CubeSats will be deployed for carrying out experiments and technology demonstrations as part of studies of the Moon, asteroids and the deep space radiation environment. Each CubeSat weighs a maximum of 13.6 kg and carries its own propulsion and navigation systems alongside its research instrumentation. The Orion’s stage adapter contains a secondary payload deployment system to separate and launch the CubeSats, with mounting brackets for COTS dispensers, cable harnesses, a vibration isolation system and an avionics unit. After separation from the Orion, and after the spacecraft is a safe distance away, the deployment system’s avionics unit will send signals to release the payloads at pre-scheduled times to allow their orbital research to begin. Mars Further out in the Solar System, NASA’s uncrewed systems are continuing to reach research milestones. In September this year for instance, a paper was published detailing how the InSight lander measured seismic and acoustic waves from four space rock impacts on the Martian surface a year earlier. It also detailed how the Mars Reconnaissance Orbiter flew over the estimated impact sites to confirm their location and capture colour close-ups of the craters. Meanwhile, the Perseverance rover (with mapping support from the Discovery UAV) has recently collected four rock-core samples from within an ancient former river delta in the Jezero Crater, an area long identified by scientists as potentially holding signs of ancient microbial life, and which means the UGV has now collected 12 scientifically compelling rock samples from the planet’s surface. While autonomous capabilities are improving all the time, operators still need to be capable of tracking uncrewed vehicles and intervening, if necessary, all in real time. At present, the comms between Earth and Mars take 5 to 20 minutes, and even if that became much shorter as a result of Martian colonisation, the absence of numerous comms satellites or any GNSS on Mars could render UAV- and UGV-based exploration a slow and arduous affair. Skypersonic, however, which is based in Michigan and has a European office in Italy, has been running simulated trials of uncrewed Mars exploration missions using a combination of its autonomous vehicles and its very low latency data link technology. It signed a 5-year contract with NASA in 2021 to provide UAV and rover software, hardware and support to NASA’s simulated Mars mission, with the simulation being performed on Mt Etna owing to its rocky and chaotic geography bearing close similarities with Martian terrain (see Video Systems focus in this issue, page 38). The mission will consist of crew members living and working in a 1700 sq ft 3D-printed module called Mars Dune Alpha. It will simulate many of the challenges of a mission on Mars, including monitoring and operating UAVs and UGVs thousands of kilometres away without access to GNSS or magnetic compasses (given the absence of a magnetic field on Mars). “Our Long Range Real-Time Remote Piloting System enables the UAV or rover and its operator to be located separately, anywhere on a world, but the comms and control are performed with extremely low latency using a simple 5G connection, and we don’t use GPS or any other satnav, which is what drew Uncrewed Systems Technology | October/November 2022 The Mars simulation tests on Mt Etna also make use of a rover UGV made by Skypersonic (Courtesy of Skypersonic)