Star Talk: With Hubble in limbo, Endeavor is off to space station

Late last month, a malfunction occurred in the instrumentation of the Hubble Space Telescope. This failure was serious enough that NASA decided to delay its repair mission to the Hubble Telescope and proceed with its next space shuttle mission.

During the last weekend in September, the Hubble Space Telescope experienced an anomaly that affected its ability to store and transmit data from its scientific instruments to Earth.

As a result, the telescope’s servicing mission that was scheduled to be launched with the space shuttle Atlantis on Oct. 10 is now under review and has been postponed until an undecided date in 2009. NASA, rightly so, wants to investigate the problem and determine what change, if any, it could have for the Hubble’s final servicing mission.

There is a backup method for the data transmission system; however, to implement this option is a complex process because a number of modules used in managing the data must also be switched over. Of concern is that these units were last tested before installation in the Hubble, a time roughly 20 years ago.

An alternative that is under study would be to send replacement parts on the next Hubble servicing mission and install these components in the telescope. This would make the itinerary for the final repair mission more formidable than the five days of spacewalks that were already planned.

Testing of a replacement data-transmission unit would first need to be done at the Goddard Space Flight Center in Maryland and then delivered to the Kennedy Space Center in Florida. NASA estimates that this course of action will take at least until January.

Endeavor shuttle

The next space shuttle mission, STS-126, will be flown by Endeavor and will transport new equipment to the Space Station. The launch is scheduled for Nov. 14 at 7:55 p.m. Endeavor’s payload includes additional living quarters for the space station’s crew, equipment for the station’s life support system, spare hardware and a treadmill.

Endeavor’s crew will be on a 15-day flight that has four spacewalks on its timetable. These extra-vehicular activities are primarily targeted for repairing and servicing the main rotary joint of the station’s solar panels. This connection allows these energy cells to rotate and track the sun. Since 2007, one of these rotary joints has shown “anomalous behavior,” so its use has been minimized. To remedy the rotary joint issue, some of its bearings will be lubricated and others replaced.

This will be the 22nd trip into space for Endeavor and the 27th time a space shuttle has flown to the space station.

Mercury loop

On Oct. 6, the Messenger planetary probe looped around the closest planet to the sun, Mercury, for the second time this year. Early the next day, Messenger sent back dramatic images of a bright crater. This crater has such an extensive pattern of rays extending from it that they reach from the planet’s northern regions deep into its southern hemisphere.

Messenger was launched Aug. 3, 2004, on an almost 5 billion-mile journey that is taking it 15 times around the sun, once by Earth, twice by Venus and three times around Mercury. Most of these orbital loops have been completed. After a few more orbits around the sun and one more around Mercury next September, Messenger will complete its winding path and enter into permanent orbit around the planet in March 2011.

Messenger will be the first spacecraft to have such an orbit around Mercury, which is the smallest of the eight planets and, on average, 50 million miles from Earth. The probe’s multibillion-mile journey was necessary in order for the gravity of the sun and inner planets to guide Messenger into the correct flight path around Mercury. The probe must match Mercury’s speed and location so it can circle in a close planetary orbit. In addition, the initial flybys of Mercury allowed the spacecraft to gather important information essential to determining its permanent orbit.

Before the Messenger mission, Mariner 10 was only spacecraft to have photographed Mercury. Mariner 10 flew by Mercury three times in 1974 and 1975 but was only able to get images of less than half the planet.

November sky

Venus has been slowly gaining altitude in the southwest since its emergence into the evening sky in June. During that time, the glow of Venus was subdued because it was positioned very low in the twilight and, therefore, also difficult to find. But since mid-October, the goddess planet has shone above the sunset glow and its eye-catching brightness is easy to notice.

Meanwhile, Jupiter, the bright starlike object found in the south-southwest as the sky gets dark, is positioned farther toward the horizon each day. Consequently, with Venus getting higher in the evening sky and Jupiter getting lower, the two planets spend November slowly closing the intervening gap between each other.

That gap will be at its minimum on the last day of November, when Venus and Jupiter make a very close pairing, low in the early evening sky. It will be a stunning display; nevertheless, this remarkable view will be outdone the next evening when the crescent moon joins the two bright planets. These three celestial objects flanking one another in the southwestern sky will create a simply spectacular sight.

Richard Monda is an astronomer living the Capital Region.