|
Author
|
Topic: STS-1 ET separation
|
Mary13
Member Posts: 24
From: Vienna, Austria, Europe
Registered: Mar 2007
|
posted 04-12-2007 03:48 PM
  
Hi!
Today STS-1 launch is 26 years ago. I reviewed some photos of the launch and I noticed that on a photo of the ET after separation the tank is full of stains and looks really terrible. What caused that?
The text under the picture:
S81-30509 (12 April 1981) --- During the STS-1 launch sequence and orbital insertion, the external tank (ET) is jettisoned from the Space Shuttle Columbia, as photographed by a camera in the umbilical bay. http://www.jsc.nasa.gov/jscfeatures/articles/000000503.html Can anybody help me to find an answer? |
KSCartist
Member Posts: 2896
From: Titusville, FL USA
Registered: Feb 2005
|
posted 04-12-2007 03:52 PM
From what I understand those "stains" are from the SRB separation motors.Tim |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
|
posted 04-12-2007 03:57 PM
Indeed, you can see similar marks on more recent tanks (the linked example is from STS-114). The stains might be more visible on STS-1 (and STS-2) due to the white paint applied over its insulation. |
spacecraft films
Member Posts: 802
From: Columbus, OH USA
Registered: Jun 2002
|
posted 04-12-2007 04:06 PM
The blackened areas are from interference heating during ascent (those that aren't clearly from the separation motors). If you'll note, they are in areas which receive the highest aerodynamic heating, as the stack increases velocity through the atmosphere. Highest areas of heating are at the top (naturally) and around the orbiter struts, where the airflow is disturbed and temperatures are highest (including around the areas where the tips of the SRBs are disturbing the airflow as well).Our "Liftoff" DVD set has the onboard footage of the STS-1 jettison (as will our Space Shuttles: First Flights set coming later this year) and gives some great views of where this interference heating occurs, but virtually any of the footage of a jettisoned ET will show it. Mark |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
|
posted 04-12-2007 04:08 PM
Edit: Mark beat me to it.It is both, however. The SRB separation motors caused the black black areas. But some of it is also from atmospheric heating, which is the dark 'charcoal powder' look evident at the top of the tank there. The friction of going through the upper atmosphere at tremendous speed can char areas, especially towards the front. In fact, the SRB exhaust plume also chars the aft come during ascent, so that is another contributor. |
Mary13
Member Posts: 24
From: Vienna, Austria, Europe
Registered: Mar 2007
|
posted 04-12-2007 04:57 PM
Thanks for your quick answers and the very helpful information. I also suspected that with the friction, but I didn't expect that to be so clearly visible.
Could you explain the thing with the SRB separation motors? How do they cause the black areas? |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
|
posted 04-12-2007 06:17 PM
On the nosecone and the aft skirts of the shuttle's SRBs are small solid motors that fire at the same time the SRBs are jettisoned. This is done in order to ensure the SRBs pull away from and behind the shuttle. As they pull away, the exhaust hits the sides of the ET.On the same note, on STS-112 when they debuted the ET cam, the separation motor exhaust hit the lens and obscured the view from SRB separation onward. This was corrected a bit for the flights of 114 and since. |
advertisement