If many heads are better than one, the same concept can be applied for satellites. A new MIT study shows that a big satellite can be no match for a group of "three to eight small, shoebox-sized satellites" in accuracy. Due to their multiple angles, they tend to have extremely meticulous measurements too.
Calculating how correctly one orbiting satellite with nine sensors is able to measure albedo, or "the amount of light reflected from Earth," experts compared them with NASA Goddard's Cloud Absorption Radiometer, which is able to gather information from thousands of different angles at one spot. With a larger number of satellites in the cluster, the measurements too were more accurate.
"We confirm the applicability of using small satellite formation flight for multi-angular earth observation to retrieve global, narrow band, narrow field-of-view albedo," explain the experts.
"The Earth does not reflect equally in all directions," said research leader Sreeja Nag. "If you don't get these multiple angles, you might under or overestimate how much it's reflecting, if you have to extrapolate from just one direction."
Moreover, a group of satellites act as support systems for each other if one fails, which is not what happens when one huge satellite flops in isolation.
With accurate measurements, it is easier to fight climate change and also calculate long-term trends and projections better.
Nag said: "Total outgoing radiation is actually one of the biggest uncertainties in climate change, because it is a complex function of where on Earth you are, what season it is, what time of day it is, and it's very difficult to ascertain how much heat leaves the Earth...If we can estimate the reflectance of different surface types, globally, frequently, and more accurately, which a cluster of satellites would let you do, then at least you've solved one part of the climate puzzle."
Even though it would be expensive, Nag feels that they should be used when "satellites need to hold a strict formation."
Experts hope that by 2026 the plan could fall in place. "Our team fully expects that a demonstration mission of this type could be flown within the next decade," said Oli de Weck, a professor with MIT's Department of Aeronautics and Astronautics.
The findings will be published in Acta Astronautica's September-October issue.
