Chandrayaan and Apollo-11 are two different lunar missions that have different objectives, designs, and durations. Chandrayaan is India’s lunar mission, while Apollo-11 is the US’s lunar mission. Chandrayaan-40 days refers to the duration of Chandrayaan-1, India’s first lunar orbiter, which was launched in 2008. Apollo-11 3 days refers to the duration of the lunar landing and return of Apollo-11, the US’s first manned lunar mission, which was launched in 1969. Here are some of the main reasons why Chandrayaan-40 days and Apollo-11 3 days have different durations:
Objectives
- Chandrayaan-1’s main objective was to map and study the lunar surface and its mineralogy, geology, topography, and atmosphere. It carried 11 scientific instruments, including a Moon Impact Probe (MIP) that was released to crash on the lunar surface.
- Apollo-11’s main objective was to land two astronauts on the lunar surface and return them safely to Earth. It carried three modules: a command module (CM), a service module (SM), and a lunar module (LM). The LM had two parts: a descent stage and an ascent stage. The descent stage carried the landing gear, engine, and equipment, while the ascent stage carried the crew cabin, engine, and equipment.
Designs
- Chandrayaan-1’s design was based on a modified version of India’s Polar Satellite Launch Vehicle (PSLV) rocket. It had a mass of about 1.4 tons and a power of about 700 watts. It used a liquid apogee motor (LAM) to raise its orbit from an initial elliptical orbit of 250 km x 23,000 km to a final circular orbit of 100 km around the moon.
- Apollo-11’s design was based on a three-stage Saturn V rocket. It had a mass of about 45 tons and a power of about 60 kilowatts. It used a trans-lunar injection (TLI) burn to escape Earth’s orbit and enter a lunar orbit of about 110 km x 314 km. It also used a lunar orbit insertion (LOI) burn and a powered descent initiation (PDI) burn to land on the moon.
Durations
- Chandrayaan-1’s duration was about 40 days from launch to end of mission. It took about 18 days to reach its final lunar orbit after performing five orbit-raising maneuvers using its LAM. It operated for about 22 days in its final orbit before it lost contact with Earth due to a technical malfunction.
- Apollo-11’s duration was about 3 days from lunar orbit insertion to splashdown on Earth. It took about 3 days to reach its lunar orbit after performing a TLI burn. It operated for about 21 hours in its lunar orbit before landing on the moon. It stayed on the moon for about 21 hours before returning to its lunar orbit. It then performed a trans-Earth injection (TEI) burn to leave the lunar orbit and re-enter Earth’s atmosphere.
I hope this response helps you understand more about why Chandrayaan-40 days and Apollo-11 3 days have different durations. If you want to learn more about these missions, please click on the links below:
- [Chandrayaan-1]
- [Apollo-11]
