Science & Tech Current Affairs

Science & Technology Current Affairs 2019-2020 category comprises current affairs with all important national / international updates in science and tech and events for the year 2019-2020 for UPSC, States, Civil services, SSC and other competitive examinations of India and States.

Fact Box: What is Citrus greening?

Citrus greening or Huanglongbing is a deadly disease of citrus which greatly affects the production of the fruits in several parts of India.

Causing agents:

  • It is caused by motile bacteria, Candidatus Liberibacter


  • Yellowing of leaf veins and adjacent tissues
  • Premature defoliation
  • Dieback of twigs
  • Decay of feeder rootlets and lateral roots.
  • Infected fruits are small, lopsided with bitter taste, may fall prematurely

How does it spread?

  • In India the bacteria are spread by a vector- the Asian citrus psyllid (Diaphorina citri).
  • It is a sap-sucking, hemipteran bug in the family, Psyllidae.

How can it be controlled?

  • It can be managed by focus Integrated Pest Management (IPM) efforts using disease-free nursery trees, reducing infection sources (inoculum) by frequent surveys and diseased tree removal, and suppressing Asian citrus psyllid through area-wide management.

India-US collaborate on Space Solar Power Initiative

Working in the direction of realizing the idea of tapping solar energy from space and beaming it to earth to meet the energy needs of the future and mitigate climate change, India and a top US science body have forged an international organisation to develop space solar power. It was declared through a joint statement made by the two sides at the 2013 National Space Society’s International Space Development Conference (ISDC 2013).                        

The renowned scientist of India Abdul Kalam and Executive Committee Chairman of the National Space Society of US, Mark Hopkins announced to have a clear plan of action to market the idea of a livable planet Earth through space solar power to G8 or G20 nations within a year.

The vision will include specific mechanisms such as the Global Space Knowledge Platform, the International Virtual Laboratory, and the International Advisory Committee that Abdul Kalam has elaborated through discussion papers.

What is Space-based Solar Power?

  • Space-based solar power (SBSP) is an idea of collecting solar power in space (using an “SPS”, that is, a “solar power satellite” or a “satellite power system”) for use on Earth.
  • Research in this directions has been going on since the early 1970s.

How it differs from current solar power systems?

  • SBSP would differ from current solar collection methods in that the means used to collect energy would reside on an orbiting satellite instead of on Earth’s surface.

What are its benefits?

  • As the outer space lacks a diffusing atmosphere and nighttime such a system can have a higher collection rate and a longer collection period.
  • Part of the solar energy is lost on its way through the atmosphere by the effects of reflection and absorption.
  • Space-based solar power systems convert sunlight to microwaves outside the atmosphere, avoiding these losses, and the downtime (and cosine losses, for fixed flat-plate collectors) due to the Earth’s rotation.

What are the hurdles in its implementation?

Besides the cost of implementing such a system, SBSP also introduces several new hurdles, primarily the problem of transmitting energy from orbit to Earth’s surface for use. Since wires extending from Earth’s surface to an orbiting satellite are neither practical nor feasible with current technology, SBSP designs generally include the use of some manner of wireless power transmission. The collecting satellite would convert solar energy into electrical energy on board, powering a microwave transmitter or laser emitter, and focus its beam toward a collector (rectenna) on the Earth’s surface. Radiation and micrometeoroid damage could also become concerns for SBSP.