Monday, July 20, 2015

Celebrating Design (of Pluto)

While reading Kenneth Chang's piece in The New York Times, The Long, Strange Trip to Pluto, and How NASA nearly Missed It, I was struck by meticulous planning for the voyage of NASA's New Horizons spacecraft. More than once, writer Chang used the word "design" in his article. And more than a few times, I thought that any kind of planning and design—no matter the purpose—faces the same sort of challenges.

Yeah. "Doh." Obvious perception. But back to the former planet Pluto.

In 2000, a study by
Dr. Stamatios Krimigis, then the head of the space department at the Johns Hopkins Applied Physics Laboratory in Maryland and a member of a committee that advised NASA on missions to the outer planets," worked like crazy to devise a cost estimate; their quick study produced the "basic design that would turn into New Horizons.
When NASA requested proposals for a competition to design a new Pluto mission, Dr. Krimigis enlisted Dr. S. Alan Stern, the head of the Southwest Research Institute's space studies department in Boulder, Colorado. Their team perfected New Horizons—which won the competition after much butt-busting (and just a bit of rocket science).

The sprint to design, build and test the spacecraft met budgetary obstacles. Sending a spacecraft into space involves far greater work than a book design (another "Doh" here), but a particular paragraph reminded me of many of budget discussion for the work in my office:

"Managers of spacecraft missions often talk about the trade-offs between cost, schedule and risk. Too quick and too cheap greatly raise the chance of failure. 'We don't believe in that,' Dr. Krimigis said."

While constructing the New Horizons spacecraft, the team used proven technologies and kept the design to the essentials—with the exception of a digital radio receiver that would consume less power. At one point, the Department of Energy informed the New Horizons team it couldn't provide enough plutonium as a power source, but the design decision to use a less power-hungry digital receiver enabled New Horizons to proceed with reduced wattage.

The last and most dramatic use of one sort of design followed by another sort of design—planning—occurred shortly after the fabulous transmissions that have us all transfixed. Ten days before the Pluto flyby, the spacecraft fell silent. The reason?
. . . the spacecraft's computer had overloaded trying to do things at once—receive instructions for the flyby while compressing images in its memory banks. By design, the main computer entered what engineers call "Safe mode to avoid damage to the spacecraft, and the backup computer kicked in.  . . . An hour and a half later, the ground stations detected the signal from the backup computer.
A smart design to avoid overload damage (from multi-tasking, which the world has learned is not possible from this piece and articles other than Chang's) led to the use of the obviously-intelligent plan to have a backup. Kenneth Chang slyly noted that although "flinging a spacecraft to a rendezvous at the edge of the solar system is indeed rocket science but not groundbreaking rocket science." But I think the forethought and collaboration and design that has New Horizons transmitting astounding data about Pluto pretty much rocks.

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