Space vehicles | Insight best to deal with them. If the debris in question is a defunct satellite for example, ideally the vehicle would repair, refuel and reposition it as needed for it to continue in service. Safe de-orbiting or recycling would follow if the satellite could not be repaired. Orbital was also recently granted a Direct-to-Phase-II SBIR contract from the US Air Force to develop carboncarbon (C/C) composite manufacturing technology, with which C/C parts could be printed for American hypersonic craft. C/C consists of carbon fibre reinforcement in a matrix of graphite, and is best known as the material used in the nose cone and leading edges of the wings on the NASA Space Shuttle. Orbital notes however that it can also be used in rockets’ nozzle linings and various structural components, satellites’ chassis and antennas, aircraft brake discs and landing gear, other vehicles’ brakes and structural components, and hydrogen fuel cell powertrains. The Moon Further out from Earth, CubeSats and SmallSats are being used to gather information for the following generation of spacecraft. NASA’s recent Lunar Flashlight for instance was sent to the Moon to survey for surface water ice in craters on the lunar South Pole. The Flashlight is a 6U CubeSat, being just under 14 kg in launch mass. Although the mission was aborted earlier this year, the project still fulfilled aims that will contribute to future missions. For one, its propulsion system ran on a green monopropellant (a fuel that does not need a second tank of additional reactant). The propellant is known as Ascent (Advanced Spacecraft Energetic Non-Toxic) and was developed by AFRL’s Rocket Propulsion Division. It has been formulated to deliver a 50% increase in density-specific impulse over hydrazine monopropellants, which are considered to be among the state of the art. In addition to its performance advantages, Ascent decreases the handling hazards compared to hydrazine, and so requires fewer personnel and less equipment during its ground operations on Earth or wherever else it might be used. The custom-designed, Ascent-fuelled propulsion system was developed by NASA’s Marshall Spaceflight Center and Georgia Tech’s Space Systems Design Laboratory to deliver over 3000 Ns (Newton-seconds) of total impulse for the orbit insertion and attitude manoeuvres. Its design uses metal additive manufacturing, custom electronics and unique micro-fluidic components, fitting overall a 2.5U volume in a bay inside the 6U vehicle, with a total wet mass of just under 6 kg. The mission was aborted en route to the Moon owing to underperformance of three of the craft’s four thrusters. This has been attributed to debris buildups in some of the fuel lines. Despite that, NASA found that many components throughout the propulsion system exceeded performance expectations, and that its non-toxic alternative to hydrazine performed well in space. Also, its survey technology, consisting of a reflectometer equipped with four lasers (which emit NIR light in wavelengths absorbed by surface water ice), performed well in all tests during the mission, satisfying NASA that the payload design will detect Lunar surface ice if applied as such. Also demonstrated were NASA’s new Sphinx flight computer, developed by JPL as a low-power computing system capable of withstanding deep space radiation. Also, an upgraded Iris radio will enable future small spacecraft to rendezvous and land on Solar System bodies. Jupiter Larger satellite vehicles start coming into play when venturing to the largest bodies in the Solar System. The ESA’s Jupiter Icy Moons Explorer (Juice) for instance was launched earlier this year, and its mission is to perform observations of the gas giant and its three ocean-bearing moons (Europa, Callisto and Ganymede) using a range of remote sensing and geophysical instruments. Through this payload it will study the three moons, in particular the bodies of liquid water that are believed to exist beneath their icy surfaces. The results of those studies are expected to help gauge their potential for harbouring lifeforms. 71 Uncrewed Systems Technology | October/November 2023 The Lunar Flashlight mission demonstrated numerous technologies for water ice surveys on the Moon’s surface
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