The three UCHII regions associated with the G34.26+0.15 high-mass star formation complex in Aquila are described, giving evidence for envelope infall, protostellar outflows, expanding ionized gas, and associated molecular hot core chemistry. The prototypical ‘cometary’ UCHII region ‘C’ in G34.26 is one focus, where the interface between ionized hydrogen (HII) and hot molecular core (HMC) gas is well observed and a rich hot core chemistry both detected and modelled in detail. Uncertainties in CH3CN formation, and the displacement of its peak emission from dust and NH3 peaks, are raised in relation to possible photodissociation in the hot core close to the UCHII-C feature.

At least 14 space agencies have identified ‘in situ resource utilization’ as a necessary capability for long-duration missions, including crewed missions to the Moon, Mars and deep space. Attention is focused on the potential production of rocket fuel from ice and water-bearing minerals. If fuel can be sourced in space, it will not need to be lifted, at great expense, from Earth’s surface. But while the mining of asteroids and other celestial bodies offers benefits, it will also create risks. Mining that is motivated purely by resource extraction could overlook or even destroy important scientific information, while physical interactions with an asteroid could alter its trajectory and, in some circumstances, potentially create a human-caused Earth impact risk. There are presently two competing efforts to develop widely agreed rules on space mining. The first is an industry-friendly effort in which the United States is engaging in bilateral negotiations with dozens of states, encouraging them to sign the non-binding Artemis Accords. The second is a multilateral effort that fully considers the interests of non-spacefaring states and is taking place in the United Nations Committee on the Peaceful Uses of Outer Space.

The global governance regime for space is grounded in six decades of co-operation between the Soviet Union and then Russia on the one hand, and the United States and its allies on the other.

But continued co-operation is not guaranteed. Following the Russian invasion of Ukraine, some elements of international space co-operation broke down immediately. Other elements, such as the International Space Station, notably continued. More worrying, perhaps, is the heavy reliance of Russian and Ukrainian forces on satellites, including, in the case of Ukraine, satellites owned and operated by private companies. This raises challenging issues of international law, including whether these private satellites are legal targets. It also raises the question of how far Russia might go in this regard. What if it decided to target SpaceX’s Starlink mega-constellation?

Sagittarius (Sgr) B2 is the most massive star-forming region in the Galaxy and the canonical HMSFR with probably the richest source of molecules detected to date, not least in the number of COMs recorded. The consequences of a variable and higher-than-standard cosmic ionization rates in this region close to the Galactic centre are discussed. They are seen to have a complex effect on COMs chemistries, offering both an unusual test bed for chemical evolution theory, while not being conditions representative of more widely observed HMSF cores. The particular case of cyanides and isocyanides stands out, and modelling that uses enhanced but extinction-dependent CR ionization rate brings best agreement between model results and observations. Nonetheless, the modelled column densities of some species are much lower than observed, and the physical structure profile of the regions appears to be responsible.

The massive giant molecular cloud (GMC) complex Westerhout 43 (W43) and its subcores are considered, in particular G29.96. HMSF is evident in clusters and the impact of disk winds and outflows on the observable chemistry made clear. Modelling of the hot core COMs abundances matches observations for many key species observed in both this and other Galactic sources. The interaction between an HII region and an associated hot dense core is exemplified in G29.96, in spite of the evident complexity of physical conditions in the surrounding region. As in all studies made through the lens of molecular emission, astronomers are able to probe the physical conditions through trace chemical emissions.

Humanity’s ascent into space began in 1929 when the German Army tested its first rocket, the A-1. But while militaries have always accounted for a large portion of human space activity, their use of the space environment has been constrained by a mutual self-interest in preserving access to it for communications, navigation, reconnaissance, weather forecasting, arms control verification and early warning. In 1962, the ‘Starfish Prime’ nuclear test demonstrated that nuclear explosions in space pose a major and indiscriminate threat to satellites. This prompted the United States and the Soviet Union to negotiate the 1963 Limited Test Ban Treaty, which prohibits nuclear tests in space. This chapter addresses such tensions between the expansion of military capabilities in space and the need to keep space free of direct conflict. The chapter highlights the growing need for a treaty to ban the testing of ‘kinetic’ anti-satellite weapons, i.e. weapons that rely on violent impacts to destroy a satellite and thus create space debris. Although Russia tested such a weapon in November 2021, the very next month the United Nations General Assembly created an ‘Open Ended Working Group on Reducing Space Threats through Norms, Rules and Principles of Responsible Behaviours’. The chapter concludes with an examination of the potentially destabilising effects of an imminent extension of military activities to cis-lunar space, the region between Earth and the Moon, including special Moon–Earth orbits.

Some 66 billion years ago, a cataclysmic collision between the Earth and an asteroid ten to 15 kilometres in diameter caused the extinction of the non-avian dinosaurs. In 1908, an asteroid 50 to 70 metres in diameter levelled over 2,000 square kilometres of forest in Siberia, while in 2013 an asteroid 19 metres in diameter produced a shockwave over Chelyabinsk, Russia, sending over a thousand people to the hospital. The field of ‘planetary defence’ involves the detection, characterisation, risk assessment and, if necessary, deflection of asteroids and comets that have the potential to strike Earth. Yet there has been a lack of high-level diplomacy on this issue. In particular, the low probability of a major Earth impact happening in our lifetime makes planetary defence a low priority for political leaders, despite the existential consequences of impacts and their eventual certainty of occurring. There is also a shortage of widely agreed international law, including on the potential use of nuclear explosive devices for deflecting asteroids. Most importantly, there is a lack of agreement on who is responsible for vetting the science, assessing the risks and making decisions if Earth were faced with an actual impact threat. Is it the United Nations Security Council that decides? What if a Security Council decision is blocked by one of its veto-holding permanent members? Would a state that acted unilaterally be excused any illegality because of the necessity of its actions, according to the international law on ‘state responsibility’?

The G24.78+0.08 source is examined as a multiple core and sub-core complex in which both ultra- and hyper-compact HII locations are identified, along with outflows, accretion disks, and hot cores. Molecular emission lines as well as radio recombination lines (RRLs) and free–free emission offer evidence for thermal, pressure, and dynamical (including infall and rotation) kinematics. Molecular line signatures trace HII/hot core interactions, and also enable estimates of the physical parameters of HMSF accretion disks (such as density, temperature, mass, and radius).

The unusual HMSFR Orion Becklin-Neuberger (Orion BN/KL) at the heart of the Orion Molecular Cloud-1 (OMC-1) is examined, with its associated explosive outflow of gas and dust. Its four well-studied features are the Hot Core, Compact Ridge, Plateau, and Extended Ridge. These sources offer much evidence for the sequential chemical processing of shocked molecular cloud material and indicate just how violent the dynamic processes associated with HMSFRs can be.