Nuclear power in the form of radioisotope thermoelectric generators (RTGs) has been used by space programs since the 1950s as an alternative to batteries, fuel cells, and solar panels. RTGs convert the heat generated by radioactive plutonium-238's decay into electrical energy via thermoelectric generators. They have been used to power spacecraft, landers, satellites and probes sent to locations where solar energy is unavailable, such as on the Apollo missions to the moon and on deep space probes. While RTGs do not produce nuclear waste like reactors, a radiological contamination risk remains if the radioactive material's containment is breached.

1. Nuclear Power in Space

2. In the 1950’ s space programs used…

3. lightweight batteries

4. fuel cells

5. And…

6. solar modules

7. to produce electricity

8. But missions started to become more difficult!

9. So…

10. The option was to use nuclear energy. NASA assembled the radioisotope thermoelectric generators. (RTG)

11. What is RTG ?

12. RTG is a generator that converts heat into electrical energy.

13. RTG uses the heat released by plutonium during its alpha decay. ( 238 Pu)

14. But how does this happen ?

15. Plutonium breaks down and as it decays it generates heat.

16. Then heat will be converted in electrical energy .

17. NASA use plutonium because it has a half-life of 87.74 years. When it decays it becomes 237 Np.

18. What is the structure of RPG?

19. It is made of a container full of radioactive material. As it decays it heats where thermoelectric generators are.

20. When was the first satellite with RTG launched?

21. It was sent in space in 1961 and it functioned for 15 years.

22. Spacecraft, landers, satellites, and probes are functioning thanks to RTG.

23. The missions Apollo 12-17 used RTG. RTG is used for navigational, meterological and for communications sattelites.

24. RTG is mostly used for probes far away from the sun where solar panels can’t receive light.

25. There are other space applications that use nuclear power.

26. There is another device that is used in spacecrafts, satellites and probes. It is called Radioisotope heater unit (RHU)

27. It uses radioactive material to produce the heat to activate electronic instruments that cannot work at cold temperatures.

28. Is RTG safe?

29. It’s safe because it doesn’t produce heat by nuclear fission so there isn’t the formation of nuclear waste

30. But . . .

31. A radiactive contamination may occur

32. It may happen that nuclear power will have to increase now that areospacial engineers are working for travel in the orbit for people.

33. http://www.absoluteastronomy.com/topics/Radioisotope_thermoelectric_generator http://en.wikipedia.org/wiki/Plutonium http:// www.wisegeek.com/what-is-a-radioisotope-thermoelectric-generator.htm http://www.qrg.northwestern.edu/projects/vss/docs/Power/1-what-are-rtgs.html Sources http://www2.jpl.nasa.gov/galileo/messenger/oldmess/RTG.html http://search.nasa.gov/search/search.jsp?nasaInclude=probes http://en.wikipedia.org/wiki/Radioisotope_heater_unit http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator#Safety