In a tiny room of his old high school, Dr. Rod Tennyson, aerospace engineer, is running an experiment with vinegar and baking soda.
Dr. Tennyson has designed protective coatings for spacecraft, and a kind of fiber-optic nerve system for airplane wings. Somewhere at home, he has an award for his part in saving the astronauts on Apollo 13. In July, Tennyson will fly to Mauritania, Africa, to speak with the ministers of 11 countries in the dry Sahel region about his plan to build a coast-to-coast pipeline full of water.
But two weeks ago, the emeritus professor was busy making tree-sale posters with students and fellow alumni in the cafeteria at Malvern Collegiate.
“Admittedly, it’s a very small thing,” he said. “But I’m hoping that it just might trickle out over time.”
That small thing is called the Sequester Project, which is all about planting trees.
Besides vinegar and baking soda, the latest Sequester Project experiment involves balloons, a set of clear plastic tubes, and 40 saplings of Norway spruce.
The goal, says Juliane Clemente, co-president of the school’s Environment Club, is to test how spruce trees grow in a high CO2 environment.
Her colleague Mary Ellen Abberger explained how, in a small room inside the school, students mix vinegar and baking soda to make CO2, which they capture in balloons and then release into tubes that keep the heavy gas around the spruce saplings.
With better evidence for how different tree species absorb CO2, Tennyson said, Canadians could coordinate a massive planting to reduce that greenhouse effect.
But as he well knows, the devil is in the details.
On April 13, 1970, Tennyson was in a morning staff meeting at the U of T Institute for Aerospace Studies (UTIAS).
That’s when a phone call came from Grumann Aerospace, the contractor that built the lunar modules for NASA’s Apollo program.
Apollo 13 had launched two days before, and was about 300,000 km from Earth. It was supposed to be NASA’s third landing on the moon.
But an oxygen tank exploded in the spacecraft’s supply module, crippling the astronauts’ navigation system and power supply.
Using sun- and star-tracking, the astronauts managed to plot an emergency course back to Earth.
Famously, they jury-rigged their lunar lander so it could support all three astronauts for four days though it was only designed for two and two – NASA’s famous “square peg in a round hole” problem.
But Hollywood forgot a critical scene in the film Apollo 13 – the one where Grumann asked Tennyson and four other UTIAS scientists to do critical calculations over the phone.
Before re-entry into Earth’s atmosphere, the astronauts had to climb into their heat-shielded command module, and jettison the lunar lander they had kept attached as their “lifeboat.”
“The biggest problem was, how do we separate from the lunar module, and yet retain our re-entry orbit so we don’t skip out of the Earth?” said Tennyson.
Too little explosive pressure, and the lunar module would come tumbling in after them. Too much, and they could blow open the command module’s seal. Either would be a deadly mistake.
Tennyson and the UTIAS team had about six hours to run the numbers, and no computers to help.
“Everything was done with a slide rule,” he said, laughing. “Have you seen a slide rule? It’s one notch higher than an abacus.”
Guided by the likes of senior engineer Bernard Etkin, a man who had what Tennyson called “enormous common sense” from 50 years’ experience, the team settled on what they thought was roughly right – 2.5 PSI – and phoned it in to Grumann.
They all worked under the impression that other teams were doing the same calculations at MIT, Caltech, and Harvard, as well as at NASA itself.
But when a congratulatory phone call came the next day, Tennyson said the people at Grumann added, “By the way, you were the only people we consulted.”
“I started to shake a bit because I’d thought, ‘What’s a couple of millimetres?’” he said, laughing. “All of us were really thinking there were other guys, a lot of them smarter than us.”
Tennyson said the great lesson of Apollo 13 is one he taught all the time to engineering students – it’s not the big-picture design, but the details that are out to get you.
A NASA review found the oxygen tank exploded mainly because a thermostatic control on its mixing fan had been set to the wrong voltage.
Since 2005, Tennyson has been working on his most big-picture task yet – a plan to build an 8,800 km, $14-billion water pipeline through 11 countries in Africa’s dry Sahel region, just below the Sahara Desert.
It would be supplied by twin desalination plants in Mauritania and Djibouti, on Africa’s western and eastern coasts.
“When you’re talking about these countries in the Sahel, there is no other option,” he said, noting that many aquifers in the region are deep and saline, and what little rainfall it normally gets has fallen off in an ongoing two-year drought.
“Sixty per cent of Mauritania is desert already, and it’s moving, predictably, every year.”
Tennyson had already done extensive work adapting fiber-optic sensor systems to oil and gas pipelines when he got inspired to design a water pipeline for the Sahel in 2005. He was watching the G8 summit on TV, and hearing world leaders pledge assistance to Africa at large.
By the time Tennyson heard about the Great Green Wall about two years ago, he had already given several papers showing the Trans-Africa Pipeline (TAP) project was technically and financially feasible. The Great Green Wall is an African Union plan to plant a line of trees on the southern edge of the Sahara.
In July, Tennyson will go to Mauritania in hope of finding a way to combine the two.
“This whole project, combined with the Pan-Africa Great Green Wall, is going to change the face of Africa,” he said. “This is going to be the largest humanitarian engineering project ever undertaken, as far as I can tell.”