The self-discharge rate for the batteries is <5% per month - not something the MER team should be concerned about.

The batteries are disconnected from the main power bus (electrically isolated) from the solar arrays during Deep Sleep. It is like pulling the plug out of the wall. You don't want to do that during the day, otherwise the batteries will not be charged. And assuming you decided to do such a thing, you would have to wait until solar array wake-up the next morning to come out of Deep Sleep...

A red dwarf's large convective zone (relative to its radiative zone) stores lots of magnetic energy, causing constant flaring and CMEs. A typical red dwarf flare makes the Sun's X-class flares look puny by comparison...

Original article at: http://dailyheadlines.uark.edu/10660.htm


University Relations
University of Arkansas

Contact:

Rick Ulrich
Professor
Ralph E. Martin Department of Chemical Engineering
College of Engineering
Deputy director, Arkansas Center for Space and Planetary Sciences
(479) 575-5645

Melissa Lutz Blouin
Director of science and research communications
University Relations
(479) 575-5555

FOR RELEASE: Thursday, April 26, 2007

Instruments to Dig Deep in Space

NASA awards University of Arkansas researchers an instrumentation grant to
build a probe for planetary rovers.

FAYETTEVILLE, Ark. - University of Arkansas researchers, in partnership with a local company will develop a probe for future planetary rovers that will help scientists study the history of the solar system by examining the properties of layers of material beneath the surface of the moon, Mars, comets and other planetary bodies.

Scientists at the Arkansas Center for Space and Planetary Sciences and officials of Space Photonics Inc. received a $403,000 grant from the Planetary Instrumentation Development branch of NASA, which will allow them to create an optical probe that can be used to determine the composition and amount of ice beneath the surface of a planetary body.

"Our intention is to deliver to NASA hardware that is ready for a mission," said Rick Ulrich, professor of chemical engineering and principal investigator for the project. This particular instrument will help researchers answer questions that have been around since planetary bodies were discovered.

"When we look out at these places, we only see the surface, and we wish we could see what lies beneath," Ulrich said. "Those layers contain the timeline of the solar system's history."

To examine the layers, the researchers will build an Optical Probe for Regolith Analysis, an instrument they refer to as OPRA.

The instrument will operate at the base of a rover, driving a spike into the soil. The spike, which may be anywhere from one to four feet long, will contain several dozen quartz windows along its length with fiber optic cables connected to an infrared spectrometer back in the rover, which will provide spectral analysis as a function of depth. Because all the electronics will be isolated in the rover, there will be no heat source to alter the possibly frigid interior of the planetary body.

"OPRA will analyze these layers without disturbing them," Ulrich said. "We'll get composition versus depth at every layer." The infrared spectrum will provide information on the kind of rock, its chemical composition, the amount of water in the rock and how the molecules are arranged. By looking at the compositions of different layers, the researchers can peel back time and look at the geologic history of the planetary body.

"NASA wants simple, robust and effective hardware, and OPRA is all three of these," Ulrich said. The public-private partnership with Space Photonics strengthens the university's ability to attract major instrumentation funding.

Space Photonics has served as a research and development company for the Department of Defense and for NASA and has reported recent product sales to Honeywell, Lockheed-Martin and Orbital Sciences.

"The relationship with the University of Arkansas has been key for us," said Matthew Leftwich, a senior development specialist and lead engineer at Space Photonics, a University-based start-up company. Space Photonics will develop the fiberoptic cable interface that will carry the infrared light signals to and from the alien soil, through the sub-surface probe. Infrared light sent to and reflected back from the alien soil into the probe's fiber-coupled interconnect system will deliver the data to the Fourier-transform infrared spectrometer for analysis.

"SPI will be collaborating with the OPRA design team to determine the optimal methods of fiber-to-quartz lens coupling and fiber routing throughout the OPRA probe," he said.

To test the instrument, the researchers will build a large sandbox-like structure that will contain a Mars soil simulant, clay or other materials that might be found on planetary bodies. They will use this and other means to test the instrument, trying to determine the force necessary to penetrate the ground, how the windows should be positioned and how many times the probe can be used before the material begins to wear. They also will compile a library of spectral results from the different materials.

"We envision that this will work on Mars, the Moon, comets and asteroids," Ulrich said. At the end of the project, the probe will be ready for NASA to consider for a mission, and it could be in space in 4 to 6 years.

Ulrich credits the work of the W.M. Keck Laboratory for Space Simulation and the multidisciplinary nature of the team for the success of the proposal - the researchers have expertise in materials science, geology, engineering, chemical engineering, fiber optics and space science. The team includes Ulrich; Larry Roe, professor of mechanical engineering; space center director Derek Sears, who holds the W.M. Keck Professor of Space and Planetary Sciences; Vincent Chevrier, a postdoctoral fellow in space and planetary sciences; and Leftwich with Space Photonics.

The Arkansas Center for Space and Planetary Sciences is a joint center in the J. William Fulbright College of Arts and Sciences and the College of Engineering.

For information, please see http://spacecenter.uark.edu.

Space Photonics develops, markets and sells optical networking systems and components specifically designed to address the reliability and bandwidth limitations of military and commercial aircraft and spacecraft.

For information, please see http://www.spacephotonics.com.

Latest HST release presents animations of Saturn and its rings:

http://hubblesite.org/newscenter/archive/releases/2007/13/

The return to Side 1 operations for SBC was recently approved, and today ACS/SBC performed its first observations (of Jupiter and Saturn's auroras in the UV) since the Side 2 failure earlier this month.

From STScI ops notes:

"The first SBC images (science and calibration) were acquired today
(Day 051). All the telemetry indicates normal conditions. The first
internal flats and dark frames are consistent with those pre-dating
the ACS Side 2 failure. There may be a small degradation in
sensitivity (on the order of 1% or less at the shortest wavelengths).
More sensitivity data will be acquired in the coming week."

It looks like the puzzling driving as seen around Sol 1078 - 1082 may have been due to the live testing of the Field D* autonav software:

http://www.cmu.edu/news/archive/2007/Febru...13_rovers.shtml

Yes, I listened in and also recorded it too, but the output was so loud (peaking at +12 dB!) that it was badly distorted.

However, I made some notes during the briefing:

Total loss of Side B electronics (fuse blown)

ACS is now running on Side A electronics in order to maintain thermal control

WFC and HRC cannot be restored on Side A since the Side A CCD Electronics Box stopped working in June 2006 (and the reason why ACS was switched to Side B)

SBC has separate power supply and likely will be restored in mid-Feb in order to support New Horizons (SBC was regularly monitoring Jupiter and Saturn's auroral activity in the FUV)

SM4 is still targeted for Sep 2008 and will not be brought forward by this issue

SM4 will not repair ACS since the electronics control box is difficult for the astronauts to access (they would have to remove the NICMOS cryocooler control system, power off other systems etc. to reach ACS electronics) - that would take two days out of the five available - not worth deleting other tasks to do that - besides the new instrument WFC3 will largely replace ACS capability

SM4 team will take heed of any review board recommendations concerning power supply issues that may affect WFC3 and COS in the same way

Loss of capability after SM4:

ACS WFC was optimized for far-red (600-900 nm) - WFC3 is better in the UV but poorer in the far-red - WFC3 would have to double exposure times to reach same depth as ACS/WFC UDF - however interest in far-red studies is waning amongst astronomy community (interest is now in Near-IR high-z studies)

HRC coronagraph most flexible and powerful ever used on HST - SM4 hope to restore STIS which has good coronagraph for protoplanetary disk studies - but not as good as HRC which opened up a whole new field of study

I've uploaded an audio recording of the press briefing for anyone who missed it:
http://www.cafesociety.uk.com/other/New-Horizons-Jupiter.mp3
(right-click on the link and select "Save Target As..." to download.

Perhaps one of these days NASA will create a searchable archive of NASA TV briefings (well I can dream...) :--)