Updated: 07 Mar 2005

TERSS News Bulletins

MODIS Direct Broadcast is On

This real-time data stream carries the data from all 36 spectral bands for the entire MODIS field of view (2330 km) whenever MODIS can be seen from a ground station.

The data stream is "free to air" (similar to NOAA AVHRR) but requires a suitably configured X-band groundstation such as the ACRES-operated ground stations at Alice Springs and Hobart (TERSS) for reception.

ACRES has been working quickly over the last couple of months to prepare its systems for MODIS reception. NASA granted a number of test passes during April and ACRES staff were delighted that a MODIS pass was successfully acquired at Alice Springs on the first attempt, Wednesday 12 April. A few days later, MODIS passes were successfully acquired at TERSS, underlining the value of maintaining identical reception systems at both sites.

In the meantime, CSIRO Marine Research division had been working on implementing the MODIS processing system elements obtained from NASA and the University of Wisconsin and integrating these with the reception system at the TERRS facility. On Wednesday 19 April we were delighted to see the first Australian MODIS scene processed through this system (see image, above). This made Australia one of the first countries in the world to successfully receive and process a MODIS scene from the direct broadcast mode.

Over the next few months, ACRES and CSIRO Marine Research will work towards a fully operational MODIS production system capable of routinely generating MODIS products in near real time. This will involve a significant effort as the NASA supplied software is still under development. We hope to include MODIS metadata and browse in the ACRES digital catalogue by 1 July 2000. In the meantime, acquisitions will continue wherever possible at both Australian groundstations. At present, reception opportunities are limited because the direct broadcast mode is switched off whenever the Terra satellite is within range of the NASA Deep Space Network. Due to the presence of the Deep Space Network station at Tidbinbilla ACT, MODIS direct broadcast acquisitions over eastern Australia have not yet been possible. NASA hopes that the issues with the Deep Space Network will be resolved over the next few months so that the volume of MODIS direct broadcast can be increased to an acceptable level.

For more information on MODIS Direct Broadcast, go to the MODIS website.

Up in the air at TERSS

Laurie McLauchlan, ACRES technician, is up in the air in a cherry picker in the photo at left, performing maintenance on the TERSS antenna on a hill at Droughty Point, Hobart Tasmania.

Both Laurie and Warren Serone, Station Manager of the ACRES Data Acquisition Facility at Alice Springs, recently spent 12 days in Hobart working on the TERSS equipment to keep it functioning at optimum level. Periodic maintenance of all receiving equipment is essential to avoid breakdowns.

One of the key tasks, for this particular TERSS visit, was to reinstall the original feed mechanism of the antenna. This equipment had been previously removed for repair.

This photo shows that taking the antenna apart is no problem for Laurie. Over time, deposits build up in areas which are only accessible by dismantling the overstructure. Items such as birds' nests and wind-blown debris can interfere with reception and must be removed from time to time.