When NASA’s new human-rated spacecraft swung around the Moon several times in November and December 2022, Canadians listened-in for its signal.
Canada’s involvement in NASA’s lunar ambitions is vast; it includes a lunar microrover and a Canadarm3 robotic arm, although its latest contribution is a trio of antennas to track the Moon mission.
“We used those antennas to track and measure Artemis on its way to the Moon by listening to their spaceship transmissions,” said Michel Doyon, the Canadian Space Agency’s manager of flight and system operations, in an interview with SkyNews.
Artemis 1 was a nearly month-long mission meant to test the readiness of the Orion spacecraft to carry humans, which Artemis 2 will do as early as 2024.
Natural Resources Canada (NRCan) runs three ground stations that normally track spacecraft signals in Earth’s orbit. They are situated around Gatineau, Québec; Prince Albert, Saskatchewan; and Inuvik, Québec. Prince Albert is the oldest of the set, having been built in 1972, and Inuvik the youngest in 2010. But all have been upgraded in the last few years, according to Doyon.
The CSA applied to NASA to supplement the normal tracking of the mission through the American agency’s large Deep Space Network (DSN), which includes three antennas spaced equally around the world to listen to missions all over the Solar System. In October 2022, the CSA was part of a select set of companies, agencies, and volunteers selected to help out.
“What we’re exploring is what is technically called one-way Doppler measurement,” said Doyon. “It gives us the [spacecraft] velocity, especially in the direction toward or away from the ground stations. By monitoring the [signal] frequency and shift, we can assess the velocity of the spacecraft.”
Though the Artemis 1 mission is complete, it will take several months to parse all the data from the antennas to see how well they performed. Early results showed promise; while Orion’s signal was not strong enough for the 13-metre dishes to watch it all the way to the Moon, the NRCan-CSA collaboration saw it as far as roughly 300,000 kilometres (around 80 per cent of the Earth-Moon distance).
“All this knowledge we learned from the experiments will be used to assess and improve how future phases of this collaboration could be performed,” said Doyon.
He also noted that DSN is busy with other missions, such as the newly launched James Webb Space Telescope, in which Canada is also a participant.
“NASA was benefitting from extra sources of information like us … it was really good for them,” said Doyon of the NRCan-CSA tracking capabilities. “We continuously learn.” The team “is really motivated to track it the best we can, to get the best results we can.”
This biweekly column by Canadian science and space journalist Elizabeth Howell focuses on a trending news topic in Canadian astronomy and space.