Space exploration is essentially a mixture of primarily planning and hard work coupled with more than a little luck. Of course luck, as the saying goes, happens when preparation meets opportunity.
In the case of the Herschel Space Observatory’s close encounter with the asteroid 2005 YU55, preparation made the opportunity. Orbiting one of the L2 points in the Earth's orbit, the European Space Agency’s Herschel operates across the far IR to submillimeter waveband. The 3.5-m telescope's primary objective is to study cooler astronomical objects with a range of instruments, including the Photoconductor Array Camera and Spectrometer (PACS). It is this instrument that it will train on the 2005 YU55 later today (November 10) at 14:55 GMT.
The path of the 400-m asteroid carried it a mere 325,000 km from Earth, inside the lunar orbit Earth. Once NASA's Goldstone Solar System Radar determined the asteroid’s exact orbit, the Herschel team was able to plan the observation details. The asteroid was positioned too close to the sun had closest approach to permit successful observations. Mission control had to wait until the configuration of the asteroid and the telescope made observations feasible.
Previously, the closest object observed by Herschel by 16,000,000 km distant. 2005 YU55 will be just 809,000 km away at the time of observation, retreating at a relative velocity of 13 km/s. The high speed forced project engineers to upgrade the observatory’s tracking software to ensure successful image capture. The PACS instrument will scan four lines parallel to the asteroid's track, then repeat a sequence 5 minutes later further along the asteroid's track. Keep an eye out for images to be released. If you can't wait, however, you can watch this image sequence gathered by Goldstone.
Speaking of opportunity meeting preparation, luck hasn't exactly been on the side of the Russian Space Agency (Roscosmos) this week. Tuesday, when it tried to send its Phobos-Grunt spacecraft on an ambitious mission to gather and return samples from the Martian moon of Phobos, propulsion problems stranded the probe in an elliptical low-Earth orbit. The plan had called for a pair of controlled burns designed to put the probe on a trajectory toward Mars—one to raise it to a 4000-km orbit, and the next to aim it at the red planet. Unfortunately, the upper stage of the booster rocket failed to execute either burn, leaving Phobos-Grunt in orbit, along with its companion, China's Yinghuo-1, the fledgling space program's first Mars satellite.
When program members reestablished connection with the probe, they discovered it had gone into safe shutdown mode. The theory is that the craft's inability to acquire the stars for navigation, perhaps because the detector saturation from Sun, cause it to abort the burns and raise its protective sidewall. In the probe’s current condition of minimal power draw, the command team believes it has as much as two weeks of time to salvage the project. Once they open the sidewall and reboot the craft, they’ll have to determine whether the glitch is software-based, in which case it could be repaired by a command upgrade, or whether it is hardware-based. If it's the latter, it could be a serious problem. According to the Roscosmos website, the Phobos-Grunt design is intended as a scalable platform slated to launch a variety of spacecraft from 2012 through 2016.
If the error does, indeed, prove fatal, it will represent the latest in a series of unsuccessful Mars missions for the Soviet/Russian space program, dating back to the 1960s. Even more sobering, it comes on the heels of slew of failed launches over the last year, most notably the August loss of a Progress 44 supply capsule destined for the International Space Station. The string of problems raised questions about the funding and prioritization of the space program, an ubiquitous problem as a time that governments around the world are concerned about cuts.
There is good news to report, however: After analysis revealed problem to be a clogged fuel line, repairs and test launches went off smoothly, leading to the successful launch of the Progress 45 resupply mission near the end of October (and given that it carried 2.8 tons of material, the crew is probably still unpacking it all). Plans call for sending up a new crew mid-to-late month.
Make no mistake about it, space exploration is a complex, challenging, expensive endeavor that requires full commitment. Done incompletely, it raises the concept of throwing good money after bad to a whole new level. Amid the ongoing budget wrangling, though, it's important to remember that space exploration is worth investing in, that done well, it can be successful and teaches surprising, delightful things about our world.
Whoops, typos from my always creative speech-recognition software. The trajectory of 2005 YU55 ran inside the moon's orbit. "The asteroid was positioned too close to the sun AT closest approach to permit successful observations." That is probably better restated as YU55's angular position relative to the sun at closest approach to Herschel led to detector saturation, so the team elected to wait until it had traveled further along its track. "Previously, the closest object observed by Herschel WAS 16,000,000 km distant." And yes, you're correct, there's only L2 point -- I was recalling the L4 and L5 Lagrangians -- clearly, too much time has passed since my last planetary dynamics class. My apologies for any confusion.
"inside the lunar orbit Earth"
"The asteroid was positioned too close to the sun had closest approach to permit successful observations."
"Previously, the closest object observed by Herschel by 16,000,000 km distant."
BTW - there is only ONE L2 point.
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