Saturday 12 September 2015

NASA’s Dirt-Scanning Satellite is Down to a Single Peeper


NASA’s - Soil Moisture Active Passive Satellite

Rocket mission to space is always a risky one and when things seem to go wrong, lethargy could lead to mishap. One such mission is the almost billion dollar Soil Moisture Active Passive – SMAP satellite that had lost one of its radar imagers a few months after coming online. SMAP’s sensors pair was intended to generate high resolution, extremely accurate maps of soil moisture, the core of the Earth’s water, energy as well as carbon cycles.

The blackened electric eye does not tend to blind the mission but does cause a hindrance to the satellite’s high definition mapping abilities and recently was announced by NASA that the extra eye was not coming back. SMAP had been launched by NASA in January to guard over the water which Earth stores in its soil where more than 97% of all the water on Earth is stored in the oceans.

The rest is sheltered up in ice caps and glaciers as of now and less than a single percent of all water on Earth seems to be in the form of soil moisture. However gallon for gallon, fraction of water seems to be of more importance than any other source on the face of the Earth which is due to the soil where the plants tend to grow.

Susceptible to Interference

The content of moisture in the soil regulates how many plants tend to grow in a certain area that controls how much carbon in absorbed out of the atmosphere. Moreover, when plants tend to absorb the carbon, they give out water vapour that provides the cool temperature on the Earth’s surface as it evaporates. The SMAP, after its winter launch tends to send soil moisture maps home in April.

 However towards July, something was incorrect with one of its paired sensors. Both the sensors were intended to collect data from the same slice of the RF spectrum but they use different systems. The `A’ in the SMAP, the active radar spring up energy from the Earth’s surface, taking the moisture readings centred on the return signature.

Dara Entekhabi, SMAP mission’s principal investigator and climate scientist at MIT informed that `the advantage is that it actually illuminates the surface having high spatial resolution, but is more susceptible to interference’.

Cause - Faulty Power Supply

The P in SMAP is the big cake pan shaped antenna that dangles off its side and as its name indicate, the passive microwave radiometer tends to sit back and gather the releases of the planet. It measures up a ton of data soil and can also see through clouds and tree cover though only views around 25 miles per pixel.

The active radar would have brought that resolution below to less than two miles but due to the active sensor affecting the big clock in the sky; the passive radiometer did everything on its own.Entekhabi has stated that the culprit was a faulty power supply and to amplify a signal, power was essential.

The failure could have been the result of faulty parts, a freak ion static occurrence or one of the several low probability events. The radar being unique was global mapping radar, producing a map every two to three days, according to Entekhabi and on a mission level, it crippled SMAP’s potentials in making high resolution maps and gather the data on how changes in soil moisture could affect long term climate.

The radar’s fleeting months of operation enabled NASA watch the climate change in real time, season vegetation changes, sea ice extent, and new bodies of water developed by melting permafrost. These maps are expected to be released later this month.

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