Posted on 12/28/2011 4:21:00 PM PST by smokingfrog
PASADENA — Two JPL-managed spacecraft designed to study the gravitational fluctuations of the moon and provide insight into the evolution of our space neighbor were hurtling closer to the moon today, and were expected to settle into orbit for the new year.
The Gravity Recovery and Interior Laboratory spacecraft were launched Sept. 10 from Cape Canaveral in Florida. The first craft, GRAIL-A was scheduled to begin orbiting the moon at 1:21 p.m. Saturday, while its twin, GRAIL-B, was expected to reach orbit at 2:05 p.m. Sunday.
"Our team may not get to partake in a traditional New Year's celebration, but I expected seeing our two spacecraft safely in lunar orbit should give us all the excitement and feeling of euphoria anyone in this line of work would ever need," said David Lehman, the GRAIL project manager at Jet Propulsion Laboratory in Pasadena.
The spacecraft took a much longer trajectory to the moon than NASA's Apollo missions, traveling 2.5 million miles and giving project managers time to monitor the performance of the craft and slowly power-up the primary science instrument aboard -- the Ultra Stable Oscillator.
The moon is roughly 250,000 miles from Earth.
Both craft will initially settle into elliptical, 11 1/2-hour orbits around the moon. Through a series of controlled burns, the craft will gradually drop down to within 34 miles of the moon, traveling in near-polar two-hour orbits.
In March, the craft will use radio signals to measure the distance between them while traveling through fluctuation gravitational areas, allowing scientists to create a high-resolution map of the moon's gravitational field.
(Excerpt) Read more at contracostatimes.com ...
As of this morning, GRAIL-A was about 65,850 miles from the moon, and traveling at about 745 mph. Its twin was 79,540 miles away and closing at a speed of 763 mph.
No doubt they will crash into each other.
The way these two spacecraft made it to the moon is just as fascinating as the mission itself. Yet you can’t find out much if anything about these “Belbruno Ballistic Trajectories”.
Where are you finding Grail mission news? The usual NASA or JPL sites aren’t current at all.
The Telecon page has the trajectory track I’ve been wanting to see. So they went towards the sun to be near that “magic” gravity point and then fell back towards the moon. Oh to see a movie of this track to see how it played out. Seeing it on a single frozen track like that is misleading.
The youtube video left out the most interesting part! That’s the part between leaving earth and arriving at the moon!
When the spacecraft were out at the point where the sun’s and earth’s gravity were of equal strength, just how easy is it to lure the spacecraft into that special route that would let them fall back towards the moon?
Ever read Edward Belbruno’s book “Fly Me to the Moon?” If not, please do.
I wonder if the instruments get turned off on the fae side when they are over all of those domed factories.
(a little tin hat humor.)
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