Good News from Mars

Posted by Sam Churchill on

NASA’s rover communicated with ground controllers early this morning, sending back some data and giving hope that normal operations might resume. And the European Mars Express orbiter has confirmed the existence of water ice in the south polar cap of Mars. The craft also beamed back a detailed photo of a channel on the red planet that might have long ago been created by flowing water. The Mars orbiter doubles as the relay station for Beagle 2, which remains mum on Mars.

NASA’s rover had gone mostly silent Wednesday, returning only beeps to acknowledge it was alive. For unknown reasons, Spirit could not transmit data. Spirit communicated for 10 minutes initially and then later for 20 minutes more, for a total of a half-hour of data transmission.

The transmissions arrived during 90-minute window of opportunity after the rover woke in the Martian morning. Data was transmitted at a rate of either 10 bits per second or 120 — two separate NASA statements give differing numbers. Officials did not indicate whether the rate was normal or how optimistic they are based on the transmissions.

“The spacecraft sent limted data in a proper response to a ground command, and we’re planning for commanding further communication sessions later today,” said Mars Exploration Rover Project Manager Pete Theisinger at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

Engineers are still baffled.

Spirit can communicate with Earth directly via an onboard “X-band” system at 8.4 GHz or it can beam signals up to either of NASA’s two orbiting spacecraft using a 420 Mhz UHF antenna. There are four chances each day to reach the orbiters. NASA receives signals from spacecraft through its Deep Space Network (DSN) of tracking stations in Australia, Spain and California.

Direct Mars-to-Earth communications are reserved for critical Spirit mission data, such as rover health and engineering. It takes about 10 minutes for a radio message, moving at the speed of light, to travel between planets. Signals transmitted to NASA’s two Mars orbiters — MGS and Mars Odyssey — can be delayed as little as 90 minutes to as long as 24 hours because of the way each orbiter works and communicates with Earth.

The European Mars Express orbiter has confirmed the existence of water ice in the south polar cap of Mars (left). The craft also beamed back a detailed photo (above). The high-resolution stereo camera shows a channel that might have been carved by water long ago.

Scientists have long known that Mars’ south pole, contains carbon dioxide ice. In fact there appears to be a vast store of frozen water mostly buried under a blanket of carbon dioxide ice, commonly called dry ice.

Now Mars Express has made the first detection of a chemical signature of the water ice at the south pole. The infrared spectrometer confirmed the presence of water ice at the south pole. Officials said today they had essentially seen the vapors of water at the surface.

“You look at the picture, look at the fingerprint and say this is water ice,” said Allen Moorehouse of European Space Agency. “This is the first time it’s been detected on the ground. This is the first direct confirmation.”

Linux has an interview with Stewart Hall, principal developer of the Linux-based Mission Control Software and Mission Planning Software for the Beagle-2.

Q: Where is Linux used in the Beagle-2 Mars lander project? What kind of Linux are you using?

A: The Mission Control Software and Mission Planning Software runs on PCs using the SuSE 8.0 distribution of Linux, at the Lander Operations Control Centre (LOCC) (National Space Centre, Leicester, UK) and the Lander Operations Planning Centre (LOPC) (Open University, Milton Keynes, UK).

Q: What is the hardware platform like?

A: Custom built PCs. B2MCS and B2MPS run on four multi-redundant PCs with cold spare + Internet gateway PC + cold spare gateway PC: all running SuSE8.0. Two GHz single processors, 60GB SCSI hard disks, CD rewriter, Matrox G450 dual head graphics using Xinerama, 2 x 22inch Ilyama monitors each, USB, floppy, basic soundcard and loudspeakers (to play system alarms).

Q: What are the origins of SCOS?

A: ESA prefers the open-source, royalty-free software develoment approach. As a world leader in space software, SciSys has been a prime mover in the development of each generation of Mission Control Software including the VMS based MSSS [Multi-Satellite Support System] and SCOS1 and then the Solaris based SCOS2 and SCOS2000. With the recent evolution to support both Solaris and Linux, Sun and PC machines, SCOS2000 is now a major contentor in the Mission Control Software marketplace. It is currently ‘flying:’ Proba (PCLinux), Mars-Express (SunSolaris), Beagle-2 (PCLinux), Rosetta (SunSolaris), Smart-1 (SunSolaris) and Integral (SunSolaris).

Q: Why was Linux chosen over, say, Solaris as the platform for SCOS?

A: Sun workstations and servers are expensive compared with PCs of similar performance and reliability. The Solaris specific SCOS2000 component architecture requires COTS [Commercial Off The Shelf] libraries that attract licence fees. The ‘evolution’ to PCLinux was a deliberate policy to reduce future operating costs.

Q: What operating systems are actually used on the Beagle itself?

A: Like the B2MCS and B2MPS, the lander on-board software was written in our Bristol office. It runs on a tailored Ada run-time kernel (XGC) for the ERC32 processor [a radiation-tolerant SPARC V7 processor developed for space applications] rather than an OS due to restricted resource constraints and stringent reliability requirements. The on-board computer is a custom design and built in Bristol by S.E.A. systems of Frome, UK, and is specifically designed to withstand rigors of spaceflight, fit within a tiny space envelope (Beagle-2 is the size of a large car tire), and interface to the science instruments and A/D electronics.

Posted by Sam Churchill on Friday, January 23rd, 2004 at 2:14 am .

Leave a Reply