US space agency NASA has revealed that its hurricane tracking missions CYGNSS is on track with all eight spacecrafts in good shape.
The CYGNSS mission, which stands for Cyclone Global Navigation Satellite System, is the first in Earth Venture program that intends to provide scientists with advanced technology to see inside tropical storms and hurricanes like never before. The satellites in the CYGNSS constellation will be making frequent and accurate measurements of ocean surface winds in and near a hurricane’s inner core – a place which has been off the limits from space till date.
The satellites will enable scientists to take measurements of regions beneath the eyewall and intense inner rainbands and to do this the mission the mission will be using both direct and reflected signals from existing GPS satellites to obtain estimates of surface wind speed over the ocean. The direct signals pinpoint CYGNSS observatory positions, while the reflected signals respond to ocean surface roughness, from which wind speed is retrieved.
The mission has eight micro-satellites for measurement of wind speeds over Earth’s oceans, increasing the ability of scientists to understand and predict hurricanes. Each satellite will take information based on the signals from four GPS satellites.
CYGNSS is taking a novel approach to calculate wind speeds that both reduces the mission’s cost and gathers more data as well.
Typically, measuring wind speed over the oceans from space uses a technique called scatterometry. A radar instrument aboard a satellite sends a signal to the ground, and measures the signal strength reflected back to it. Building both sending and receiving capabilities into a single instrument, however, is more expensive than the method being used on CYGNSS.
The CYGNSS satellites will only receive signals broadcast to them from GPS satellites already orbiting the Earth and the reflection of the same satellite’s signal reflected from the earth. The CYGNSS satellites themselves will not broadcast. And according to Chris Ruf of the University of Michigan and the mission’s principal investigator, that will result in significant cost savings.
The use of eight satellites will also increase the area on Earth that can be measured. The instruments will be deployed separately around the planet, with successive satellites passing over the same region every 12 minutes. As the CYGNSS and GPS constellations move around the earth, the interaction of the two systems will result in a new image of wind speed over the entire tropics every few hours, compared to every few days for a single satellite.