Guardians against the galaxy: Tekapo couple honoured for planetary defence contributions

RNZ News

3 days ago

Pam Kilmartin and Alan Gilmore pictured with Mt John's 1-metre telescope in 2019.
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Supplied / Fraser Gunn
For 50 years Pam Kilmartin and Alan Gilmore have quietly worked to track asteroids that could pose a threat to Earth.
The couple, now in their 70s, had contributed detailed observations to international planetary defence programmes, using their vantage point in Tekapo and teamwork to swiftly gather unique data.
Their work saw them jointly awarded the New Zealand Order of Merit, although Kilmartin said she was "terrified" at the thought of receiving the honour.
"I don't really know how we came to get something like this. We have just been doing what we like for the last 50 years," she said.
"We kind of feel a bit guilty about being honoured for what is fun for us."
Kilmartin and Gilmore had discovered 41 asteroids, a comet and a nova - the latter two being "accidental" discoveries, Gilmore said.
The couple established a programme tracking near-Earth asteroids, initially from Wellington's Carter Observatory and later from the University of Canterbury's Mt John Observatory in 1980.
Kilmartin and Gilmore with Ned and their telescope at their home in Happy Valley, Wellington in 1979.
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In the 1980s, evidence was mounting that an asteroid impact had caused the extinction of the dinosaurs and astronomers around the world were becoming increasingly aware of the potential threat posed by near-earth objects.
Observatories around the world began tracking asteroids larger wider that 140 metres, within 20 times the moon's distance to Earth - that is, close enough to pose a collision risk.
Kilmartin and Gilmore saw a gap in global search efforts: "the absence of any such work in the Southern Hemisphere," Gilmore said.
Most of the discoveries were made by search programmes in Arizona and Hawaii, he explained.
"Because we're in the Southern Hemisphere, there is a there is a parallax effect, that is, we're looking at the asteroid from a slightly different direction. That enables them to triangulate, to get a distance measurement estimate for the asteroid, and that improves the orbit calculation very quickly. So our location in New Zealand is very helpful for this work," he said.
"The idea is to find these objects before they find us...to come up with technology that could divert it a little bit."
Such technology was put to the test in 2022 during NASA's DART mission, which
successfully knocked a stadium-sized asteroid off-course
.
With their sons Ned (Edmond) aged about 6 years old and Chris, about 1, at the University house in Lake Tekapo Village in 1983
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Kilmartin said her "vague" interest in astronomy was kindled in the small country town where she grew up, where "the stars were part of the scenery".
Later, she deepened that interest at the Auckland Astronomical Society, joining a group of women learning the art of photoelectric photometry - a process to measure the brightness of stars.
For Gilmore, the catalyst was seeing a shooting star while walking with his father one night in the 1950s.
He was further inspired by a "neat little book on practical astronomy" that he found at the Hutt Intermediate School library that taught him how to make a telescope.
By secondary school he was so adept at handling telescopes that he was invited to help test out possible sites for the University of Pennsylvania to set up a southern observation station in New Zealand.
The pair met at an astronomical conference in Christchurch and married in Wellington in 1974 while working at the Carter Observatory - Kilmartin as an information officer and Gilmore as a researcher.
It was then that they began working as a team, producing precise measurements that would put them on the international radar.
"What really got us on the international scene was Michael Clark at Mt John Observatory discovered a small comet. He sent photographic plates of the comet to the Carter Observatory and Pam and I got more photos of it, and we measured up those plates and we produced the first precise positions of that comet globally," Gilmore said.
The couple with their home telescope in Tekapo in 2020
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The pair see their teamwork as a secret weapon, which allows them to report observations potentially faster than any other astronomy group in the world, Gilmore said.
"We sort of share our skills back and forth," Kilmartin said.
"Like they say, the sum is greater than its parts...we can be reporting observations internationally, literally within minutes of making them, because there's two of us operating," Gilmore said.
"I'm controlling the telescope, selecting the next target and then operating the cameras that we have on the telescopes, that take many, many pictures. Pam drags those across to her laptop and runs a piece of software called Astrometrica which stacks the images so that we can find a particular asteroid. And then Astrometrica is able to measure the position of the asteroid and it produces the data in a format that we can then just simply paste into a website for the Minor Planet Centre in Cambridge, Massachusetts."
Gilmore twice served as president of the Royal Astronomical Society of New Zealand and edited its newsletter for 22 years, while Kilmartin was secretary for 18 years.
A NZ Post 'New Zealand Space Pioneers' stamp dedicated to the couple in 2019
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From 1996 until their retirement in 2014, Gilmore was also Mt John Observatory's resident superintendent, managing its day-to-day operation.
Gilmore had to learn to drive a tractor, while Kilmartin did "an awful lot of work shovelling snow off the paths and tracks", as well as hosting thousands of school children and visitors for tours.
Now living in Tekapo with a large telescope at home, Gilmore said the couple continued to host groups.
"We've tried to get involved with keeping our community involved and informed in astronomy," he said.
"We send out, for instance, sets of sky charts every month, e-mailing them out to about 400 addresses. Some of them are schools and so on that circulate them to pupils."
They said they were heartened by local growth in astro-tourism.
Astronomy will "enhance your life," Kilmartin said, whether as a hobby or a career.
More than a decade after their retirement, the pair continued making observations and sending data to the Minor Planet Centre.
Gilmore said the University of Canterbury still supported them as "sort of honorary research associates", allowing them to access telescope time.
"We just, for instance, worked until 1am this morning before clouds came in on one of the Mt John telescopes," he said.
"Our work continues to be useful. It's not in any way cutting edge work, but it's a very handy contribution to international astronomy."
Closer to Earth, champion of the country's plant science sector Alison Stewart has been recognised as a Dame Companion of the New Zealand Order of Merit.
The current Foundation for Arable Research chief executive said the honour was a "very pleasant surprise" and exciting recognition for her field.
"Plant science doesn't normally get profiled in this way," she said.
Stewart has dedicated a 40-year career to sustainable plant protection, soil biology and plant bio-technology.
Her work is credited for the commercialisation of biocontrol products used by New Zealand and overseas growers.
She has also pioneered sustainable farming practices to improve crop yields and quality while minimising environmental impacts.
Stewart said it had been gratifying work.
"When the commercial companies that I've worked with have got products out in the marketplace that are being used by growers in New Zealand to support their sustainable production practices - and those products came from research that my research team has done over the 40 years... gosh, that's really nice to see," she said.
Stewart was chief science officer at Marrone Bio Innovations in the US from 2013 to 2015, and general manager Forestry Science at Scion from 2015 to 2018.
She describes her career as "a collection of all the things that I love doing, wrapped up into the most amazing jobs."
Stewart said the recognition was not just about her.
"I see it very much as a shout out for all those plant scientists in the country who do an amazing job to look after our native flora and support the development of our plant food producers," she said.
"I think of the number of postgraduate students that I have supervised over the years. Seeing all of them go out to work in New Zealand companies - and they are now becoming leaders in their own right - I get a huge amount of satisfaction knowing that I contributed a little bit."