Aditya-L1 and further Indian missions to the Sun

Swesh

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RHU is used for heating, while RTG is used for generating electricity.....RHU is heater, while RTG is a generator
RHUs are small devices that use the decay of plutonium-238 to provide heat to keep spacecraft components and systems warm so that the equipment can survive long enough in the cold space environment to complete its mission. This heat is transferred to spacecraft structures, systems, and instruments directly, without moving parts or intervening electronic components.

By using RHUs, the spacecraft designer can allocate scarce spacecraft electrical power to operate the spacecraft systems and instruments. RHUs also provide the added benefit of reducing potential interference (electromagnetic interference) with instruments or electronics that might be generated by electrical heating systems.

RHU Montage
Radioisotope Heater Units have been critical for providing heat to keep some spacecraft warm enough to accomplish their missions, including the battery powered Galileo and Huygens probes and the two solar powered Mars Exploration Rovers.
An RHU contains a Pu-238 fuel pellet about the size of a pencil eraser and outputs about 1 Watt of heat. (The entire RHU is about the size of a C-cell battery.) Some missions employ just a few RHUs for extra heat, while others have dozens.
 

Swesh

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Like a steady campfire that warms intrepid
hikers in a remote forest, radioisotope heater
units (RHUs) help bring dependable heat to
wherever it’s needed for missions bound for
the coldest corners of the solar system.


The electronics and mechanical systems
used by modern spacecraft may need
assistance in maintaining their proper
operating temperatures, even when
toughened for space travel. For example,
the temperatures on Earth’s moon can swing
from +250 degrees Fahrenheit in sunlight to
-250 degrees in the dark within a matter of
minutes, and conditions in deep space are
often even colder
 

Swesh

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Radioisotope Thermoelectric Generators (RTGs) are lightweight, compact spacecraft power systems that are extraordinarily reliable.

RTGs provide electrical power using heat from the natural radioactive decay of plutonium-238, in the form of plutonium dioxide. The large difference in temperature between this hot fuel and the cold environment of space is applied across special solid-state metallic junctions called thermocouples, which generates an electrical current using no moving parts.
 

Swesh

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This is last update in RTG

ISRO, BARC join hands to develop nuclear engines for rockets
Updated - July 16, 2023 at 05:40 PM. | Chennai, July 16
To develop radio thermoelectric generators
BY M RAMESH

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| Photo Credit: JOTHI RAMALINGAM B
India’s space agency, ISRO, is jointly developing a nuclear-powered engine along with Bhabha Atomic Research Center (BARC), it is reliably learnt.

Chemical engines, such as those that power the thrusters in satellites, are fine up to a point, but if you want to send a spacecraft deep into space, such as into interplanetary missions, they will not do — neither can they carry that much fuel nor can they be solar powered because sunlight will not reach a solar panel at such long distances.

Hence, nuclear-powered engines. According to sources, ISRO-BARC are developing what are called Radio thermoelectric generators (RTGs). “The work has already begun and has been identified as a major task that has to be completed soon,” said the source.

The nuclear engines are not to be thought of as nuclear fission reactors that generate electricity. The RTGs use radioactive materials, such as Plutonium-238 or Strontium-90, which release heat as they decay.

Essentially, the engine contains two parts — the radioisotope heater unit (RHU) which generates heat — and the RTG, which converts the heat into electricity.

Thermocouple
This heat is transferred to a ‘thermocouple’ — a material that develops a voltage if there is a heat gradient across it. To put it in simple terms, think of it as a rod — if one end is hot and the other end is not, there will be a voltage across the rod (Seebeck Effect). The voltage can be harnessed to charge batteries that can provide motive force to a satellite. ISRO is targeting a 5W RTG, it is learnt.

“RTGs are independent of solar proximity and planetary alignment. This characteristic would help in minimising constraints like the ‘launch windows’ that the scientists have to operate within,” says Nitansha Bansal, a cyber security specialist with Columbia University, in an article for the Observer Research Foundation (ORF).

RTGs, however, are not entirely new. US spacecrafts such as the Voyager, Cassini and Curiosity have been powered by RTGs
 

Swesh

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This is last update in RTG

ISRO, BARC join hands to develop nuclear engines for rockets
Updated - July 16, 2023 at 05:40 PM. | Chennai, July 16
To develop radio thermoelectric generators
BY M RAMESH

comment COMMENTS
SHARE
READ LATER

| Photo Credit: JOTHI RAMALINGAM B
India’s space agency, ISRO, is jointly developing a nuclear-powered engine along with Bhabha Atomic Research Center (BARC), it is reliably learnt.

Chemical engines, such as those that power the thrusters in satellites, are fine up to a point, but if you want to send a spacecraft deep into space, such as into interplanetary missions, they will not do — neither can they carry that much fuel nor can they be solar powered because sunlight will not reach a solar panel at such long distances.

Hence, nuclear-powered engines. According to sources, ISRO-BARC are developing what are called Radio thermoelectric generators (RTGs). “The work has already begun and has been identified as a major task that has to be completed soon,” said the source.

The nuclear engines are not to be thought of as nuclear fission reactors that generate electricity. The RTGs use radioactive materials, such as Plutonium-238 or Strontium-90, which release heat as they decay.

Essentially, the engine contains two parts — the radioisotope heater unit (RHU) which generates heat — and the RTG, which converts the heat into electricity.

Thermocouple
This heat is transferred to a ‘thermocouple’ — a material that develops a voltage if there is a heat gradient across it. To put it in simple terms, think of it as a rod — if one end is hot and the other end is not, there will be a voltage across the rod (Seebeck Effect). The voltage can be harnessed to charge batteries that can provide motive force to a satellite. ISRO is targeting a 5W RTG, it is learnt.

“RTGs are independent of solar proximity and planetary alignment. This characteristic would help in minimising constraints like the ‘launch windows’ that the scientists have to operate within,” says Nitansha Bansal, a cyber security specialist with Columbia University, in an article for the Observer Research Foundation (ORF).

RTGs, however, are not entirely new. US spacecrafts such as the Voyager, Cassini and Curiosity have been powered by RTGs
 

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PSLV-C57/
🛰️
Aditya-L1 Mission: The launch of Aditya-L1, the first space-based Indian observatory to study the Sun
☀️
, is scheduled for
🗓️
September 2, 2023, at
🕛
11:50 Hrs. IST from Sriharikota. Citizens are invited to witness the launch from the Launch View Gallery at Sriharikota by registering here:
Commencement of registration will be announced there. https://isro.gov.in/Aditya_L1.html
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