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Gravity Probe B Takes Flight

An educator’s conference is held in conjunction with the launch from Vandenberg AFB

by Michelle Evans


Einstein came up with a relatively simple equation, and yet it has a profound impact on how we view our universe. His 1916 Theory of General Relativity has stood the test of time and passed everything thrown at it over the intervening years, but that doesn’t stop scientists from testing the limits to make sure that what we believe to be true is true. The nature of science always forces us to ask the next question. If something doesn’t fit, we don’t throw it out, we have to delve into new theories until we find the truth that is, not the truth we want to see.


One component of Einstein’s theory states that any massive object will warp the fabric of space, like dropping a large ball onto a stretched piece of rubber. A second component of the theory states that a massive rotating body such as Earth will actually grab the framework of space-time and drag that frame along with it. This “frame dragging” is sort of like riding a bicycle and having your pant leg caught in the sprocket gear. Of course in real space-time, the effect is extremely small and has never been able to be measured until now.


Thus enter the world of Gravity Probe B. Dr. Leonard Schiff of California’s Stanford University, first postulated 40 years ago that space warping (the geodetic effect) and frame dragging, would result if Einstein was correct. The problem has been that since that time, no one could build the instruments with the precision necessary to do the experimental measurements that would prove or disprove the theory. After four decades of work, that has finally changed.


Gravity Probe B is 21-feet long, nearly 9-feet in diameter, and has a mass of 6,820 pounds. The heart of GP-B is a 5.5-inch optical telescope that will lock onto the star IM Pegasi. Four ultra-precise, ping pong ball-sized gyroscopes will measure any changes in orientation caused by frame dragging and space warping. If the angles recorded by instruments connected to the gyroscopes measure the minute angles expected, then Einstein will be proven correct again. If the angles measured are not within the expected numbers, the universe as we know it will take a topsy-turvy turn because this will mean that what we thought was true, is not.


The gyros, the telescope, and the mounting block for these units are made of fused quartz. They will be unaffected by temperature extremes in space as the vehicle makes a polar orbit at 400 miles altitude over the two year testing period. The gyros are so precise that they are considered the most spherical objects ever made by humans. Our jagged Earth deviates from sea level by approximately ±30,000 feet. If these super-smooth gyros were enlarged to the size of our planet, the largest deviation would be only ±8 feet. What this precision means is that GP-B can measure angles as small as one-half milliarcsecond (see graphic at the bottom of page 4).


To get Gravity Probe B into orbit required a launch aboard a Delta 2 rocket and the polar orbit requirement meant the launch had to take place from Vandenberg Air Force Base on the central California coast. Problems with spacecraft development delayed the experiment many times, the most recent being last December. Finally, all was ready and a launch date was set for April 18. Then a last minute change forced a further one day delay. All of this is wearing enough on the nerves of the launch crew, however, in this case there were other important people scrambling to meet the changes in launch dates. The Endeavour Center, in association with Stanford University, NASA, Hancock College, and the California Space Authority, organized an Educator’s Launch Conference to coincide with the launch of Gravity Probe B. The conference was scheduled on April 18, with viewing of the launch the following morning from the VIP site.


From throughout California and even as far away as Minnesota and Australia, approximately 150 teachers came to participate. “The purpose of the conference is to share applied math and science with the teachers through curriculum and hands-on activities,” said Edmund Burke, OCSS member and president of the Endeavour Center.


One of the many others present was Pam Leestma, another member of OCSS and a teacher at Valley Christian School in Bellflower. She said, “I teach 2nd grade and most of what was shared at the conference was way over the heads of my students and sometimes me, except for this one fact, ‘If you can dream it, you can do it!’ This came through loud and clear and was very easy for me to take back to my classroom. I was most impressed with Dr. Francis Everett, who is the head scientist of the Gravity Probe B project. This has been a long journey for Dr. Everett and his team. Talk about perseverance. He had a dream and he went for it, even though it took 40 years.”


Don Scott, a former NASA educator. Don was also a key player in this conference. He made the presentation titled “Arte Scientia,” where he showed the attendees how Leonardo da Vinci’s concept of melding art and science is so important in our classrooms. His former boss at NASA was Garth Hull. Don told me that Garth served on the advisory committee that helped bring the conference together. Don said “I think it is okay to say — at least from my point of view — that Garth believes the launch conferences offer a wonderful opportunity for NASA to get science content information into the hands of teachers, and to allow teachers to interact with NASA scientists. This conference launches a new stage in the program, with a non-governmental organization running the program rather than NASA Education.”


“This will be one of many,” Burke pledged when asked about future conferences. This conference went extremely well and the enthusiasm present was well in evidence even when the original launch was scrubbed with just three minutes to go due to high-level winds. Some of the educators and guests had to go home, but they never felt short-changed by anything they experienced. Many were able to stay and watch the successful liftoff the following morning, April 20 at 09:57:24 PT.


“This is a chance to see a launch, and to me it’s mind boggling they can measure something like the space-time warp with a satellite. It surprises me they can make measurements that accurate,” said Jerald Jenson, a Tustin High School teacher.


Pam was one of the teachers unable to spend the extra day after the launch scrub on April 19. “I wanted to experience the thrill of the sound enveloping my being and feel my bones rattle like it is when I have seen my cousin (Dave Leestma) launch into space aboard the Space Shuttle. Edmund and his team had worked so hard up to this point and this was to be the frosting on the cake. As the minutes counted down with little time left, we heard on the speakers that the launch was scrubbed until the next day. I was disappointed since I would have to get back to my classroom the next morning and miss it, but it was a beautiful morning, the Sun was shining, I had met some very nice people, I had had a little break from teaching, and I was with my good friends, Marty Waldman, Edmund, and Space Cowboy Scott Hollister. I will just have to wait until next time for a Delta launch and that will be just fine with me!”


The launch was picture perfect, if a day late. The Educator’s Launch Conference was superb and will serve as the model for many more to come. Teaching science, math, and space exploration can find no better proponents than all those involved with this endeavor. Now we wait as the science team gathers their data over the next two years to find out if Einstein was correct or if our model of the universe will be replaced by something even more bizarre. Stay tuned.