United States Current Affairs

US Scientists develop micropropulsion system based on liquid water

Engineers from Purdue University in US have designed and tested a micropropulsion system called a Film-Evaporation MEMS Tunable Array (FEMTA) thruster that uses liquid water as the propellant for orbital maneuvering of tiny satellites called CubeSats.


CubeSats are basically miniature satellites which typically weigh around two kilograms. In the future, they have potential to carry out tasks like imaging and remote-sensing currently performed by heavier satellites which are expensive to build and launch. CubeSats at present cannot totally replace their larger counterparts as they are incapable of changing orbit or performing complex manoeuvres as they donot have a propulsion system. If CubeSats would be having system would allow such tiny satellites to correct their orbit or maintain their altitude, thereby prolonging their operating life in space before becoming space debris.

Film-Evaporation MEMS Tunable Array (FEMTA)

The FEMTA system uses an innovative design of small thrusters that deliver bursts of water vapor to manoeuvre the spacecraft into different orbits. It uses pure water as the propellant since it is safe, green, easy to use and free from the risk of contaminating sensitive instruments by the backflow from plumes as in the case of thrusters using chemical propellants.

It uses capillaries thinner than human hair through which the propellant water can flow. Small heaters located near the ends of the capillaries turn the water into vapor, which, on escaping provides the thrust. The minuscule capillaries act like valves that can be turned on and off by activating the heaters. It is compact and not power hungry. The technology is said to be similar to the inkjet printer, which uses heaters that fire dots of ink of ink at the paper.


Scientists for first time edit genes of human embryos

Scientists from Oregon Health and Science University, US for first time have successfully edited genes of human embryos to correct defective DNA that cause inherited diseases.

They had used the CRISPR-Cas9 genome editing technology to alter human DNA in single-cell embryos, which allows specific sections of DNA to be altered or replaced.

Key Facts

In this experiment, scientists had used sperm donated from men who carried inherited disease mutations to demonstrate that the genes can be corrected. The one-celled embryos were created in the experiment, were never intended to be implanted into a womb and were only allowed to develop for a few days.

They had used a process called “germline engineering” in which genetically modified organisms pass changes to their offspring to eradicate inherited disease. It allowed so-called permanent germline changes to pass down to any offspring.

The research holds great potential to avoid many genetic diseases, but has raised fears of “designer babies”. It is also considered as a milestone in journey for giving birth to the first genetically modified humans.

CRISPR-Cas9 genome editing technology

CRISPR short form of clustered regularly interspaced short palindromic repeats. It allows scientists to selectively edit genome parts and replace them with new DNA stretches. CRISPR is a collection of DNA sequences that direct Cas9 where to cut and paste. Cas9 is an enzyme that can edit DNA, allowing the alteration of genetic patterns by genome modification. CRISPR-Cas9 technology has the potential to revolutionise the treatment of blood diseases, tumours and other genetic diseases.