Starry Nights @ SFU: Space shuttle Discovery Reentry

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Re-entry of Space Shuttle Discovery, Tuesday April 20, 2010!

In the wee hours of Tuesday April 20 2010, the space shuttle Discovery re-entered the Earth's atmosphere on a rare "descending node" flight path, which took it just North of Vancouver, on its way to a successful landing at the Kennedy Space Centre in Florida.

This was the last chance to see the shuttle re-enter over continental North America (the usual trajectory coming from the South-West over Central America), with only three flights to go before the fleet is retired. It would have been a stunning sight, with the shuttle arcing high in the sky over the Lower Mainland, and at a distance of only 100km from Vancouver at closest approach.

I kept our members apprised of a rapidly changing situation with several email updates over the course of three days, including early morning postings on both the Monday (the original date for the landing) and Tuesday, as I watched live feeds from Mission Control, to prepare for the flyover, via NASA TV. (The feed through spacevidcast.com was especially good - thanks to Kenneth Lui for the link.) Unfortunately the greater Vancouver area was awash in cloud and rain on Tuesday morning, though happily, many members reported hearing the shuttle's sonic boom (its speed over BC would have been roughly Mach 22!). I received messages from as far away as the Kootenays! (More on all that below - be sure to checkout the email reports that I received, in the frame to the right!)

I would like to thank Prof. Ash Parameswaran of the School of Engineering Science for alerting me to this exciting event! We both saw a shuttle re-entry over Vancouver in the mid 1990s. That was a stunning sight, one of the most memorable celestial apparitions I have ever witnessed: on that occaison, the re-entering shuttle was an eerie, brilliant orange, and streaked very rapidly across the sky.

Discovery's STS-131 mission was originally scheduled for a landing in the morning of Monday April 19, but poor weather at Kennedy caused a postponement until the next day. The first landing attempt on Tuesday, which would have brought the shuttle over Vancouver just past 4AM, was also scrubbed, and we had to wait for a decision on the next landing attempt, which could have taken place either at Kennedy, or at Edwards Air Force Base in California (which would not have been a favourable path for sighting from Vancouver).

It was exciting that the landing was finally set for Kennedy, on what would have been for us the most favourable of all the possible re-entries, but unfortunately the cloud and rain in the greater Vancouver area did not let up. Nonetheless, many of our members reported the satisfaction of hearing the sonic boom created by the passing shuttle. I heard a single, extended and very deep boom that echoed off the houses on my street at 5:50AM, just over 4 minutes past the shuttle's closest approach. The shuttle actually creates a double sonic boom that can be made out if the trajectory is right, since it's big enough for distinct shock waves to be produced by both the leading and trailing edges of the spacecraft. However, a double boom was not resolved according to accounts by our members.

I was thrilled to get many email messages from members recounting their observations. This made for a very exciting communal expereince, despite not being able to see the fly-over. I hope you'll enjoy reading through these messages in the frame to the right. I've also included messages from members who saw the shuttle and the space station in orbit over Vancouver on Monday morning, in the orbit from which Discovery would have descended had it landed as originally scheduled.

Here for the record is some data on the shuttle's flight path as it would have been seen from Vancouver:

The shuttle would have been seen to rise to the North-West at 5:43:14AM.
It would have reached its highest point over the horizon to the North-East, at 5:45:33AM, at 47 degrees of altitude (half-way from the horizon to the point over-head!).
It would have been seen to set to the East at 5:47:35AM.
The shuttle was only 100 km away at closest approach!
Here's a PDF file with the trajectory over Vancouver for this reentry (thanks to a NASA calculator).

Starry-eyed
@ SFU since Nov. 2007