[amsat-bb] AMSAT-NA totally metric?
gregory.beat at comcast.net
Sat Jan 20 08:18:33 PST 2007
The news article below, leads to a question about the current Eagle project
as well as future AMSAT-NA projects.
All metric measurement based?
NASA boldly goes with Metric System (SI)
TOM SPEARS, CanWest News Service
Published: Friday, January 12, 2007
NASA has finally agreed to fly to the moon in metric - a move its
scientists have wanted ever since they mixed up kilometres with miles
and crashed an expensive spacecraft near Mars.
Space is an international business. And NASA says that only scientists
of the United States, Myanmar and Liberia still measure distance in
NASA's Vision for Space Exploration calls for returning astronauts to
the moon by 2020 and eventually setting up a manned lunar outpost.
This week, the agency announced it will make the lunar project a
NASA quotes a senior moon mission manager, Jeff Volosin, as saying: "I
think NASA has been seen as maybe a bit stubborn by other space
agencies in the past, so this was important as a gesture of our
willingness to be co-operative when it comes to the moon."
The change, announced after talks with space agencies from Canada and
14 other nations, could leave any space experts in Myanmar and Liberia
on their own. Canada, however, seems pleased.
"Space engineering is tough enough without continuously having to
remember all the conversion factors between various units," said Ben
Quine, a professor of space engineering at York University.
"So it's good news that they're joining us, and good news for
"All of our courses are taught in SI (metric measure, abbreviated from
the French Systeme international) so it will make it easier for our
graduates to get jobs south of the border."
A probe called Mars Climate Orbiter reached Mars in 1999, but entered
far too low in orbit and crashed on its first loop around the planet's
far side. NASA later said its engineers had messed up a conversion of
orbital information from metric to imperial units.
NASA started using metric measurements in some operations in 1990, but
much of its work - such as aspects of shuttle missions and the
International Space Station - continues in miles, pounds and gallons.
"My favorite imperial unit is the slug. The launch force of the
shuttle is measured in slugs," Quine said. (The slug is defined as the
mass that receives an acceleration of one foot per second per second
when a force of one pound is applied to it.)
Making the change won't be easy for the Americans, he noted.
"Everybody has to be careful with their units when they convert." But
he says it will make calculations easier in the long run. Everything
fits together by tens, hundreds and so on.
"The foot was based on the size of the foot of one of the kings of
England. I can't remember which one it is now. That's no way to run a
space program, based on the size of a dead king's foot."
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