Free «Landsat 7» Essay

Part 1

1. When was it launched?

On April 15, 1999 Landsat 7 was launched from Vandenberg Air Force Base, California (Parkinson, Ward, King., 2006).

2. What are the details of the orbit?

The orbit is circular and sun-synchronous type, polar, with a 98.2° inclination, at an altitude of 705km. The orbital period is 98.9 min and the cycle repeats every 16 days (Parkinson et al., 2006).

3. What kind of detectors does it have?

Landsat 7 has an Enhanced Thematic Mapper Plus (ETM+) which is “an 8-band imaging radiometer aimed at providing high spatial resolution, multispectral images of the sunlit land surface, using visible, near-infrared, shortwave infrared, and thermal infrared wavelength bands, along with a panchromatic band” (Parkinson et al., 2006, p. 178). Landsat 7 has also an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), MISR, and MODIS sensors.

4. What is the main scientific purpose of the mission?

• Sustain Landsat data continuity with the provision of imagery consistent in terms of acquisition geometry, spatial resolution, calibration, coverage and spectral characteristics, and calibration with previous Landsat imagery.

• Generate and continually update a global archive of substantially cloud-free sunlit land-mass imagery.

• Continue providing Landsat-type data to the U.S. and international users at the cost of satisfying user needs, and expand the application of such data for global change research and commercial use.

5. What are the main results?

The mission has produced and continues to update a global archive with considerably cloud-free, sunlit images. “The higher spatial resolution of ETM+ data from Landsat 7 allows researchers to determine the actual causes of observed land-cover changes. These changes have important implications, both for local habitability and the global cycling of carbon, nitrogen, and water” (Parkinson et al., 2006, p. 176). 

Part 2

4. Technological offshoot of the space program

One of the biggest issues with space flight is cost. There are two mitigating factors when considering the cost of space flight, one is the scientific knowledge that is gained and the other is the technological offshoots of space flight. Satellite communications, weather forecasting, earth observation satellites monitoring climate change, global positioning satellites that help planes navigate safely, the technological offshoots of space activities offer important benefits to all humankind (Stevenson, 2009). Many of the products and services people enjoy today are rooted in technology developed by National Aeronautics and Space Administration (NASA) in its pursuit to explore space.

“Scientists at NASA Langley Research Center have been researching and developing lasers for remote sensing (monitoring and measuring) of Earth's atmosphere since the technology was in its infancy” (Allen, 1996). NASA Langley's work in the laser technology development has found appliance in manufacturing and medicine. Engineers of NASA Langley were crucial in the development of a more efficient and reliable laser technology tool named the diode pump laser. In response to the industrial demand for the above mentioned laser, NASA Langleycollaborated with other organizations to remove the diode semi-conductor from the lab project and make it a product which is commercialized. NASA Langley has greatly contributed to the development of a more efficient laser used in medical operations such as arterial repairs and incisions.

5. What are the policy implications of these kinds of choices?

Sending humans into space is far more expensive than using robots. Since people need a bigger spacecraft with special conditions and recourses like air, environmental control systems, toilet facilities, food, water, etc. Since robots do not need all that to function, they are much more cost efficient. However, there are some advantages in sending people instead of robots in the outer space. Humans have a bigger range of task-solving abilities compared to the robot technology available today. People are able to reason and solve problems that may arise. Another important reason for sending people into space is colonization. Some people speculate on possible disasters that could destroy all humankind on the Earth, some say we will run out of resources at our current rate of consumption.

Stephen Hawking says “I don’t think the human race will survive the next thousand years, unless we spread into space. There are too many accidents that can befall life on a single planet. But I’m an optimist. We will reach out to the stars” (cited in Stevenson, 2009). Colonization is the obvious long term solution and the only way to learn how to survive in space or other planets is by sending humans out there.