A few days ago, the Chinese National Space Administration launched its Tianwen-1 mission to Mars from its launch site in Hainan province. It is slated to hit the Red Planet in April 2021, when it will face the daunting task of launching a surface probe from its orbiting component, which will launch a rover once it has reached the surface. Like all of these missions, it is in constant contact with its field controllers, and as with any radio transmission floating through the ether, the radio pirate community has received its telemetry and has been analyzed by [r00t].
Immediately there is something interesting in the modulation scheme, instead of a carrier with modulation applied, there is an unmodulated main core carrier, and the data appears on a series of subcarriers. Is this a feature of being a space probe, the unmodulated carrier that makes it easier to find and track in deep space?
They quickly find the telemetry operator and decode their frames. It carries a series of data sets, including position data and instrumentation. From the positional data they can determine when the ship has made a change of course, and from the sensor data, such as the solar sensor, its movement can be deduced and plotted. It is a fascinating vision of the mission, and we are grateful for the analysis.
Mars is a notoriously difficult target for space probes, somewhere that multiple missions have failed for various reasons. We hope that the Tianwen-1 mission is finally successful and that in time the Chinese space people will show us in due course some of the fruits of their work. They’re not alone at launch this month, so we’ve got a ton of Mars-related stories to look forward to next year.
Header image: Tianwen-1 rover mockup. Pablo de León / CC BY-SA 3.0
