In an earlier article for SpaceDaily (Guessing Games For Japan's "Information Gathering Satellite" Program, October 11, 2006) I set forth a case for the possible configuration of Japan's earlier spy satellite launch. This was a high-resolution optical satellite that lifted off in September. I suggested that this satellite would probably draw much of its components from the Advanced Land Observation Satellite, or ALOS, which performed a similar mission of observing the Earth beneath it.

The use of the basic "bus" for the ALOS satellite would save time and improve the potential reliability of the mission. Engineers don't like to re-invent the wheel. With this in mind, I would also suggest that ALOS is the father (or mother) of the radar spy satellite.

ALOS itself carried a synthetic aperture radar array, which folded out in a sequence of flat panels after launch. A high-resolution radar system could be a derivative of this. Add more panels, improve the electronics, and you've upgraded a civilian system to military-standard imaging. So the radar satellite is probably even closer in design to the original ALOS satellite than the previously launched optical satellite.

Given the apparent focus on radar imaging, it seems likely that there will be no high-resolution optical camera on this latest satellite. So we can ditch the complex optical scanners carried on ALOS without adding any other camera to replace them.

Radar is power-hungry, and ALOS itself carried a huge solar panel to feed its radar array and other sensors. A larger, more sensitive radar would probably require even more power. So there have probably been no cuts to the size of the solar panel on the radar bird. Contrast this to the optical satellite, which would presumably have lower power requirements than ALOS, and thus presumably carries a smaller solar panel.

Would the radar satellite have an even larger solar panel than ALOS? It's difficult to say. Even though the radar is drawing more power, there are no ALOS-style optical sensors to support. So some power loads have been cut. This could be enough to balance out the increase in demand for the radar. In any case, the mission could simply manage its power more judiciously.

The illustration appearing with this article represents a speculative mockup of the satellite, based on these principles. The illustration shows a large Synthetic Aperture Radar array dominating the spacecraft, while the solar panel remains of the same size.

What will the radar look at? Apart from being able to see in the dark, radar also has the ability to see underground. Japan's principal strategic worry at the moment is North Korea. In fact, the 1998 flight of a North Korean missile over Japanese airspace actually instigated Japan's spy satellite program. Since then, a salvo of missile tests and a nuclear explosion have only added to concerns.

North Korea is known to have a extensive array of underground facilities, including tunnels designed to carry troops under the Demilitarized Zone into South Korea. It's possible that this radar satellite could assist in monitoring North Korea's underground infrastructure, including caverns dug for nuclear testing.

How much are we likely to know for sure? Probably little to nothing. Japan has been quite cagey about disclosing any details of its Information Gathering Satellite program. No images taken from either an IGS optical or radar satellite have ever been released to the public. But it was interesting to observe the Japanese government making statements in the media prior to the North Korean nuclear test in October this year.

The government had no qualms about saying that satellite observations had revealed preparations for a test, even though no pictures were shown to back up these claims. Similar statements were made prior to the July 4 missile salvo. So Japan evidently feels confident to make statements based on the data from these satellites, even if the data itself remains concealed. It's also possible, but not proven, that their own views were reinforced by intelligence shared by the USA, presumably collected by their own satellites.

At the time of writing, the launch date for the next Information Gathering Satellite has not been announced. An announcement will probably be made just a few days before the actual flight. But it will be fun to watch the launch, or at least try! Will JAXA, Japan's space agency, turn its launch site Web cam away from the pad again?

Dr Morris Jones is a lecturer at Deakin University, Australia

Related Links
All about the technology of space and more

Memory Foam Mattress Review

SPACE MEDIA NETWORK PROMOTIONS Solar Energy Solutions Tempur-Pedic Mattress Comparison ... Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News