Gaia/Hipparcos: project interviews
Hipparcos is the first time since Sputnik in 1957 that a major new development in space science has come from outside the United States.
Freeman Dyson (Infinite in All Directions, 1988)
Starting in 2021, I have been recording interviews with some of the people that played a part in shaping the developments of space astrometry.
These include some of the engineers and managers from the European Space Agency and its industrial teams involved in the Hipparcos and Gaia projects, some of the leading scientists, and just a few of the individuals at the forefront of ground-based astrometry in the years leading up to the move to space. Several others are planned.
Amongst these, it is interesting to hear that two senior people, with key roles in the development of Gaia, both initially considered that the measurement goals targeted by the mission were not achievable!
My thanks to all those who have taken part, and to Moby for the use of his unreleased track Morning Span in their introduction (https://mobygratis.com). The order below follows the date of the interview.
PPM, Hipparcos-Tycho, and Gaia
Ulrich Bastian (Haardt, Palatinate, Germany, 1951) started his long career in astrometry with his involvement in the ground-based activities of the Astronomisches Rechen-Institut (ARI, Heidelberg) in the early 1980s. He made leading contributions to the Hipparcos-Tycho project in the 1980s and 1990s and, since the earliest days of the Gaia mission 30 years ago, has played a central role in a number of critical activities, which continue to this day. We look back over this period of major advances in astrometry.
2 Nov 2023
Gaia: industrial system engineering: part 2
Frédéric Faye (Dijon, 1963) joins me for a second time. In an earlier conversation we talked about the earliest phases of the Gaia project in industry, 10 years or so before launch, and looked at the complexities that were lying ahead when he took over responsibility for the systems engineering in 2005. In this second part, Frédéric describes the organisation of his system engineering group, and some of the management and organisational challenges that his team had to deal with.
12 Jul 2023
Gaia: industrial system engineering: part 1
Frédéric Faye (Dijon, 1963) was the System Engineering Manager for the Gaia satellite. Within the industrial prime contractor team, Airbus Defence & Space, he was in charge of the satellite design, integration and verification, from 2005, all the way through to the in-orbit commissioning review that took place a few months after the successful spacecraft insertion around L2 in 2014. Today, we're talking about his central role in the design, manufacture, assembly, testing, and launch of Gaia.
12 Jul 2023
The Hipparcos mission
Lennart Lindegren (Svalöv, Sweden, 1950) joins me for a second time. In an earlier conversation we talked about the period leading up to the adoption of Hipparcos in 1980. Today (as in my second conversation with Erik Høg), we discuss the Hipparcos mission, from its acceptance in 1980 to its completion in 1997. We talk about his role in the mission development, and in the preparation for - and the analysis of - the data sent down from the satellite. We also talk about his memories of the satellite launch in 1989, and of finalising the Hipparcos Catalogue.
13 Oct 2022
Validation of the Gaia catalogue data releases
In the second of our two-part interview, Claus Fabricius talks about his activities after Hipparcos. With astrometry no longer supported financially in Denmark, Claus moved to the University of Barcelona in 2005, joining the active Gaia team there to work on the initial data treatment and on the photometry. Later, he took over responsibility for the validation of the successive versions of the Gaia Data Releases, and here he talks about the many tests that are made, pre-publication, on the astrometric and photometric results.
5 Sept 2022
Astrometry in Copenhagen pre-Hipparcos
Claus Fabricius (Copenhagen, 1954) spent the first part of his career at the Copenhagen University Observatory in Denmark, where he worked on one of the main instruments contributing to ground-based astrometry in the years preceding Hipparcos. In the first of this two-part interview, Claus talks about his involvement in the development and operation of the Brorfelde transit circle, later as the Carlsberg Automatic Meridian Circle in La Palma, and in the creation of the Tycho Catalogue and its associated initiatives.
5 Sept 2022
Gaia satellite operations: part 1
David Milligan (Blackpool, UK, 1971) joined ESA, at its operations centre, ESOC in Germany, in 2000. There, from 2008 to the end of 2020, he was the Spacecraft Operations Manager for Gaia, the leader of the team responsible for its operation, health, and safety. In the first of this two-part interview, David talks about the preparations for the satellite operations in the years leading up to launch, and the major tasks involved in sending it on its way to its intended L2 orbit, 1.5 million km from Earth.
7 Jul 2022
Gaia satellite operations: part 2
In the second of our two-part interview, David Milligan, Spacecraft Operations Manager for Gaia, describes the challenges involved in the spacecraft commissioning, including the problems of 'icing' and 'straylight'. And he talks about keeping the satellite operational and optimised over almost a decade, including optimisation to allow the downlink of significantly more data, and the various tiny effects that can be detected, including bubbles in the propulsion system, micro-meteorites, and the effects of sunspots.
7 Jul 2022
The design of the Gaia photometric system
Carme Jordi (Barcelona, 1958) is a senior research scientist at the University of Barcelona. She played a key part in designing the photometric measurements that could - and should - be made with Gaia, and played a key role in the preparation for the photometric data analysis. We talk about the scientific rationale for making photometric observations from the satellite itself, the considerations underlying the design of the photometric system, and how the photometric measurements compare with the original plans.
8 Jun 2022
Gaia... and beyond
Erik Høg (Lolland, Denmark, 1932) joins me for a third time. In our first conversation we talked about his early involvement in ground-based astrometry, and his part in getting Hipparcos optimised and adopted by ESA in the 1970s–1980s. In the second, we talked about his involvement in Hipparcos, from its acceptance in 1980 to completion in 1997, including his ideas for the Tycho experiment. Today, we talk about his contributions to Gaia [recorded 9 February]. Erik's transcripts are at https://arxiv.org/abs/2208.09332
2 Jun 2022