While the world is adjusting to a “new normality” and still trying to make the best out of a global pandemic due to Covid 19, we have seen nature take a breath after months of reduced human intervention. We now look at the much clearer sky and might ask ourselves how much we actually do know about the ensemble playing of nature and wildlife as planet earth and the universe. What is the bigger picture?
This is what the researchers of the Gaia mission have tried to find out more about. Launched in 2013 and originally scheduled for 5.5 years, European Space Agency’s Gaia mission is now in its extended phase. It is exploring the position and velocity of more than a billion stars, creating the largest and most precise 3D map of the Milky Way.
Its results influence practically every area of modern astrophysical research and, with over 1000 publications in one year, Gaia is one of the most productive science missions ever.
The mission celebrated great success and the team behind it has now won the ESA Team Award. The team involves several directorates alongside the science community and international institutional and industrial contributors, including Telespazio.
Thanks to its know-how in all phases of a space mission, Telespazio played an important role in Gaia with numerous experts in mission planning systems, flight control teams as well as with highly qualified space controllers.
We asked to our colleague Mark Clements, part of the Software Support Team of GAIA, as also David Milligan, Gaia Spacecraft Operations Manager for ESA, for their personal experience and insights of the mission.
Mark, what was the most exciting moment for you personally throughout the mission?
Well, I can say there have been several moments I would label as ‘exciting’ in the mission to date, but I guess the standout moment for me and probably also others was the Gaia launch itself.
This was a moment when the whole Gaia team was involved – myself as part of software support, the flight control team, the flight dynamics team, and many other persons from Telespazio and the European Space Operations Centre, ESOC. One can never foresee what problems can occur and when – even though many hours of Simulations campaign had been exercised prior to the launch in anticipation of possible problems. There was a definite buzz in the air from everyone concerned during launch – hoping that the Spacecraft launch was successful, and entering the required orbit.
And of course, we were a bit anxious that our small part in the ground systems held up during these critical moments!
That sounds thrilling! In a mission that aims at providing high accuracy positional and velocity measurements for about one billion stars and spectroscopy for about 150 million stars, there also must have been some challenges you faced.
Our work at Telespazio for Gaia, during the lifetime of this mission, requires the supervision of many different interrelated ground systems - often with specialised support teams and upgrade histories. Trying to harmonise all these systems into a reliable and working whole - enabling the Flight Control Team (and others) to do their job efficiently can be very challenging. There always seems to be an on-going system upgrade in work!
From Telespazio’s side, the experience and dedication to the people involved definitely contributed to help overcome this on-going challenge.
This image shows Gaia's all-sky view of the Milky Way based on measurements of almost 1.7 billion stars. ESA/Gaia/DPAC, CC BY-SA 3.0 IGO
As you already talk about how you overcame challenges, what did you learn during the mission that surprised you the most?
For me it would be the extraordinary degree of accuracy required in many different aspects of the mission and spacecraft. For example, the various timing accuracies required which even require taking into account relativistic effects, extremely accurate spacecraft attitude control, the detection and compensation of Spacecraft related effects – e.g. even able to detect the passing of sunspots on the Sun from unrelated Spacecraft measurements (!) - and the ability of the flight control team and mission scientists to compensate for all these. This results in the ability of the mission to construct the star catalogues containing the positions, and proper motion of 1 billion stars with hugely impressive accuracy.
The following question goes to David. As Gaia Spacecraft Operations Manager you had to coordinate teams from different international institutions, industry contributors as well as the science community. How difficult has this task been for you?
At ESA, we’re used to working across Europe and with a plethora of organisations. In general, there’s a lot of enthusiasm and everyone wants the mission to be a success, so regardless of the team you’re working in: When the goals are similar, we usually don’t face big problems.
And which role did Gaia’s Mission Data System and Software Support team play during the mission?
Our Mission Control System is the fundamental tool we use to monitor and control the spacecraft. All data from the spacecraft, both scientific and engineering, comes through the mission data systems, which is nice to think about when looking at the latest map or scientific result. Gaia was also the first to use some of the new mission data system functionalities that have come on-line in the recent years, such as the better telemetry visualisation of the EGOS user desktop or automated operations through MATIS. The software support team is very important in keeping the mission data systems in good shape and helping the Flight Control Team bring in new functionalities to improve the operations.
What are you most proud of as the Spacecraft Operations Manager of the Gaia mission?
If I had to pick one thing, then I’d say playing a key part in Gaia’s overall mission. Gaia’s scientific impact is phenomenal and is increasing with time, with a publication rate that is already one of the highest of any ESA mission. What we do in mission operations is a really important link in the overall chain that makes this possible.
To give an example, after the commissioning phase of the first six months of the mission it was clear that Gaia was capable of measuring many more stars than the 1 billion it was designed for. In a few weeks, we changed the operations concept so we could get all this data down – and without that the latest map releases would not contain the big increase from 1 to 1.7 billion stars that have been possible.
David Milligan, Head of the Gaia Spacecraft Operations Unit (OPS-OAG), at ESOC
In your opinion, Mark, what do you think made the team win this award? What do you think was especially good?
I think it is a combination of experience, but also dedication from the many teams involved – working together to achieve the impressive Gaia astronomical goals. Able to solve engineering challenges and always improving the spacecraft and ground systems – often it seems with original solutions to problems that may well have never happened before.
What is your opinion on how the team won this highly rated award, David?
As Mark also says, I think the winning of the award did not base on one single aspect. The Gaia mission has been a major effort over many years and the scientific impact is now clear and rising. To reach the extraordinary mapping precision and volume that Gaia does, means the full system (spacecraft, mission operations, science operations and data processing) is full of challenges and novel solutions that were needed to overcome those challenges. To take an example from mission operations, once flying we decided to add a third time correlation chain into our Mission Control System. This had to consider Einsteinian general relativistic effects due to gravitational and kinetic time dilation. Gaia is the first mission to do this at ESOC and it has allowed us to better monitor our accurate ground station and spacecraft atomic clock.
As you are still in the last phases of the mission: How have operations been affected by the Corona lockdown? And how could you make sure the teamwork is still strong in the missions you are leading?
Yes, like everyone else there’s been a big impact of the lockdown! We are, like many organisations, almost entirely working from home, with key tasks still done from ESOC, such as spacecraft commanding. With modern tools, and the adaptability and willingness of people, a lot can still be done. A simple thing we did in the Flight Control Team, right from day one, was to have a short 10-15 minute Skype first thing every day, with webcams on and coffees in hand, so we can see and talk to each other and keep a bit of social contact and promote teamwork. Beyond that it’s the professionalism and adaptability that keeps things running so well.