1. Astronomy facilities support many critical functions of space exploration and space science.
Did you know that many aspects of space exploration and space capabilities are dependent upon the role of ground-based astronomical observatories? Certain space assets require their three-dimensional position to be known to very high precision. The European Space Agency’s (ESA) Gaia satellite, launched in 2013, is observing over one billion stars in the Milky Way to determine their proper motions and positions. To achieve this astrometry data for target stars requires Gaia’s velocity to be known to within 2.5 millimetres per second, and its position in the sky to within 150 m – a significant challenge given that it operates at 1.5 Million kilometres from Earth! To overcome this challenge, the mission concept included a regular observing campaign by a network of optical ground-based telescopes, including ESO’s VLT Survey Telescope (VST) to determine with high precision Gaia’s location against background stars.
2. The best science requires both space and ground astronomy facilities.
Space and ground assets operate in a synergistic manner, based on each capability’s complementary strengths. In terms of astronomy and planetary science, space-based observatories are free from the optical disturbances and absorbing properties of Earth’s atmosphere and can view all wavelengths of light, yet it is usually either impossible or very costly to repair or change instrumentation once they are launched. Consequently, space observatories are generally higher cost and are subject to more stringent design-mission trade-offs. On the other hand, ground-based observatories rely on computer-controlled and laser-assisted adaptive optics systems to mitigate for the atmospheric turbulence, and cannot see all wavelengths, but their instrumentation packages can be rapidly and flexibly adjusted and maintained to meet new scientific requirements.
3.Astronomy is an important source of technology and capacity development for a global space economy.
The first way in which many potential scientists and explorers in developing countries experience exploration of the cosmos is through ground-based astronomy, often by using small commercially available telescopes, building and operating small ground-based observing facilities, or using publicly available archive data. This builds capacity, increases the visibility of space as a vehicle for development and often acts as a gateway to develop a national capability in space science. The International Astronomical Union’s Office for Development plays a key role in facilitating this goal. Many of the national delegates from developing countries sitting at the United Nations COPUOS are former astronomers, and the astronomy sector in the country is often one of the driving forces for establishing a space sector.
4. Astronomers may one day save humanity on Earth, and then the Moon.
From climate change to nuclear war, humankind faces many mostly self-inflicted threats, yet one from which we are completely free from blame is that posed by asteroids or comets, collectively termed near-earth objects (NEO). One only has to look at the highly cratered surface the Moon, which lacks the protective envelope of the atmosphere, to understand the problem. Earth will likely be impacted by at least one rocky / iron asteroid of 100 metres in size on the timescale of 10 millennia, causing devastating regional effects or global tsunamis. Yet given the incomplete knowledge about the local population of NEOs, we don't know exactly when such an impact could occur. Thankfully, due to the work of astronomers we can rest safely.
5. Astronomy has played—and continues to play—a foundational role in driving humankind’s passion for space exploration.
Humankind has looked to the heavens for millennia in search of meaning and understanding about how the Universe works. The endless frontier of the cosmos has spurred our curiosity to explore and to develop scientific methods to do so, with wide-ranging impacts on our society. Astronomy has given us essential knowledge about the fundamental forces of the Universe in addition to multiple technology spin-offs and a large body of skills and technologies in optics, detectors, radio receivers and communications, which are essential to space travel. There is no reason to doubt that further discoveries from the nature of the solar system's rocky bodies to a fundamental understanding of gravity, will contribute to further possibilities in exploring space. In turn, improved capabilities in space exploration will open the door to new possibilities in astronomical research. A robust human presence on the Moon, for example, would allow for amazing astronomy projects.