Landsat 5
The current mission director for Landsat 5 (Steve) gave a talk today at lunch in the Pickford Theater, which was really way more interesting than one would think.
Here is the deal. Since about 1970, the US Government has been putting Landsat satellites into orbit about the Earth, where they loop round and round, taking photos of the ground from several hunderds kilometers up, and relaying them back to Sioux Falls, SD, or a ground station in Columbia, MD. These are shared internationally, and the 2.6 million photos are available FOR FREE at the NASA website, which is darned convenient for anyone who wants to see a photo of the same place on the Earth at the same time of day at about 16-day intervals for 40 years. According to Steve, this is devilishly useful to how policies that impact land usage are working, how waterways are changing, glaciers receding, etc.
http://landsatlook.usgs.gov/
Landsat 5 is 705 km up, and after its launch in March of 1984 under the plan for a 3 year life, is still in orbit. With some tinkering, it has remained in service, dutifully snappy photos from above us all for 29 years. (This is literally a Guiness Book of World Records record for live orbiting stuff.)
One of its back-up gyros has finally failed, and this is apparently the last straw for safety reasons - a 2 and quarter ton piece of space junk, if its guidance totally failed, could take out other satelites. This year they are working to do maneuvers to run out its hydrazine fuel tanks so it doesn't fall with that auxiliary tank full of N3H4 or whatever onto someone. A backup, Landsat 7 is on orbit and ready to take over once they can get the damn thing empty. It has the auxiliary fuel because the plan in 1984 was for a polar orbit space shuttle, which would pick it up after three years and ferry it back down, and it needed the extra fuel for safe transition to the much lower orbit this polar shuttle would have, but, haha, no shuttle was ever built.
I was able to ask a reasonable technical question afterwards at the Q&A because at some point my father had been rambling on about Skymap and how it was used by satellites for attitude adjustment in case of tumble or just needing to tweak an orbit. Must call Dad and tell him.
EDIT: Pop says he worked on Landsat 1 and 2, but expressed admiration that 5 had stayed flying so long. He asked me if Steve were a sawed off redhead, and I had to tell him that no matter what Steve's original haircolor had been, it was gray now. Steve Covington, that was his name. I couldn't think of it. Maybe next phone call.
Here is the deal. Since about 1970, the US Government has been putting Landsat satellites into orbit about the Earth, where they loop round and round, taking photos of the ground from several hunderds kilometers up, and relaying them back to Sioux Falls, SD, or a ground station in Columbia, MD. These are shared internationally, and the 2.6 million photos are available FOR FREE at the NASA website, which is darned convenient for anyone who wants to see a photo of the same place on the Earth at the same time of day at about 16-day intervals for 40 years. According to Steve, this is devilishly useful to how policies that impact land usage are working, how waterways are changing, glaciers receding, etc.
http://landsatlook.usgs.gov/
Landsat 5 is 705 km up, and after its launch in March of 1984 under the plan for a 3 year life, is still in orbit. With some tinkering, it has remained in service, dutifully snappy photos from above us all for 29 years. (This is literally a Guiness Book of World Records record for live orbiting stuff.)
One of its back-up gyros has finally failed, and this is apparently the last straw for safety reasons - a 2 and quarter ton piece of space junk, if its guidance totally failed, could take out other satelites. This year they are working to do maneuvers to run out its hydrazine fuel tanks so it doesn't fall with that auxiliary tank full of N3H4 or whatever onto someone. A backup, Landsat 7 is on orbit and ready to take over once they can get the damn thing empty. It has the auxiliary fuel because the plan in 1984 was for a polar orbit space shuttle, which would pick it up after three years and ferry it back down, and it needed the extra fuel for safe transition to the much lower orbit this polar shuttle would have, but, haha, no shuttle was ever built.
I was able to ask a reasonable technical question afterwards at the Q&A because at some point my father had been rambling on about Skymap and how it was used by satellites for attitude adjustment in case of tumble or just needing to tweak an orbit. Must call Dad and tell him.
EDIT: Pop says he worked on Landsat 1 and 2, but expressed admiration that 5 had stayed flying so long. He asked me if Steve were a sawed off redhead, and I had to tell him that no matter what Steve's original haircolor had been, it was gray now. Steve Covington, that was his name. I couldn't think of it. Maybe next phone call.