cheehh@jetson.uh.edu (05/28/90)
I was wondering why Columbia was being launched at night since the
payload is not a spy satellite bound for a 62 degree orbit to overfly
the USSR and nor is it an interplanetary probe requiring a precise
launch window available only at that particular time. And I was going to
pose that question to the gurus of sci.space but the May 21 AW&ST gave the
answer and I though I'd post it here in case anyone else was interested.
Apparently, the telescopes aboard Astro-1 will be at their best in
the "night" phases on the orbit. Also, they will be unable to function
while the shuttle is in the North Atlantic Anomaly (NAA). Hence, by
launching at that time of the night, they will get into an orbit where
most transitions through the NAA will be during the day. Hence, they
will not have to waste valuable observation time. Does anyone have
any comments/corrections about this?
--
-------------------------------------------------------------------------------
............. | Rikhit Arora
And, while with silent, lifting mind I've trod | cheehh@uhupvm1.bitnet
The high untrespassed sanctity of space, | cheehh@jane.uh.edu
Put out my hand, and touched the face of God. | ~~~~~~~~~~~~~~~~~~
-------------------------------------------------------------------------------henry@utzoo.uucp (Henry Spencer) (05/28/90)
In article <6282.266023d3@jetson.uh.edu> cheehh@jetson.uh.edu writes: > Apparently, the telescopes aboard Astro-1 will be at their best in >the "night" phases on the orbit. Also, they will be unable to function >while the shuttle is in the North Atlantic Anomaly (NAA)... > Does anyone have any comments/corrections about this? Just one: there is no North Atlantic Anomaly as far as I know. The reference is probably to the South Atlantic Anomaly, an area over the southern Atlantic where the inner Van Allen belt is unusually close to the Earth. It's a major nuisance to spacecraft with sensitive detectors. This fits with the night launch. From a northern launch site, a night launch into low-inclination orbit gives you an orbit with its northern end on the night side of the Earth and its southern end on the day side. -- As a user I'll take speed over| Henry Spencer at U of Toronto Zoology features any day. -A.Tanenbaum| uunet!attcan!utzoo!henry henry@zoo.toronto.edu
mosley@peyote.cactus.org (Bob Mosley III) (05/29/90)
...out of curiosity, what's the "North Atlantic Anomaly"? OM
thomas@mvac23.UUCP (Thomas Lapp) (05/29/90)
> Apparently, the telescopes aboard Astro-1 will be at their best in > the "night" phases on the orbit. Also, they will be unable to function > while the shuttle is in the North Atlantic Anomaly (NAA). Hence, by If this has been brought up before, please e-mail the response to me. Otherwise.... What is the NAA (North American Anomaly)? I've not seen it referred to before. - tom -- internet : mvac23!thomas@udel.edu or thomas%mvac23@udel.edu uucp : {ucbvax,mcvax,psuvax1,uunet}!udel!mvac23!thomas Europe Bitnet: THOMAS1@GRATHUN1 Location: Newark, DE, USA Quote : The only way to win thermonuclear war is not to play. -- The UUCP Mailer
clj@ksr.com (Chris Jones) (05/29/90)
In article <6282.266023d3@jetson.uh.edu>, cheehh@jetson writes: > > I was wondering why Columbia was being launched at night [...] > > Apparently, the telescopes aboard Astro-1 will be at their best in >the "night" phases on the orbit. Also, they will be unable to function >while the shuttle is in the North Atlantic Anomaly (NAA). That's South Atlantic Anamoly (SAA), a region where the inner Van Allen radiation belt is relatively close to the earth. > Does anyone have >any comments/corrections about this? Yup.
baalke@mars.jpl.nasa.gov (Ron Baalke) (05/29/90)
In article <780@peyote.cactus.org> mosley@peyote.cactus.org (Bob Mosley III) writes: > >...out of curiosity, what's the "North Atlantic Anomaly"? > The North Atlantic Anomaly is the region where the Van Allen belt interferes with radio transmissions in the upper atmosphere. The space shuttle will stop their communications with Earth when passing through this region. There is a corresponding South Pacific Anomaly on the other side of the globe. _ _____ _ | | | __ \ | | Ron Baalke | baalke@mars.jpl.nasa.gov | | | |__) | | | Jet Propulsion Lab | baalke@jems.jpl.nasa.gov ___| | | ___/ | |___ M/S 301-355 | |_____/ |_| |_____| Pasadena, CA 91109 |
dieter@rwthinf.UUCP (Dieter Kreuer) (05/29/90)
In article <1990May28.153022.20010@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > This fits with the night launch. From a northern launch site, a night > launch into low-inclination orbit gives you an orbit with its northern > end on the night side of the Earth and its southern end on the day side. > -- For how long is this orientation of the orbit stable (it is certainly perturbed by Sun, Moon, atmospheric deceleration, revolution of Earth around Sun etc.)? I don't doubt that it will be stable for the whole STS-35 mission, I'm just curious about how big these impacts might be. |============================================================================== | . . . . _____ . . . * .| Dieter Kreuer | | . * . . / O \ . + . . | Lehrstuhl Informatik IV | | . . +. * |\ O O /| . * . | RWTH Aachen | | ____________ | \___//| . ____________ | Ahornstr. 55 | | /_/_/_/_/_/_/__| |___|/|___/_/_/_/_/_/_/ . | D-5100 Aachen | | /_/_/_/_/_/_/ . | |___|/| /_/_/_/_/_/_/ | F.R.Germany | | . . . \ |___|//. . +. . | | | .* . \|___|/ . * : . | Phone: +49-241-804523 | | . * . /. \ .* =============| Fax: +49-241-806295 | | . +. . . / . \. . / E-Mail: dieter@informatik.rwth-aachen.de | | . . / .+ \. / dieter@rwthinf.uucp | |==============================================================================
cheehh@jetson.uh.edu (05/30/90)
In article <649@ksr.UUCP>, clj@ksr.com (Chris Jones) writes: > > That's South Atlantic Anamoly (SAA), a region where the inner Van Allen > radiation belt is relatively close to the earth. OK OK, I goofed. My placement of the anomaly was anomalous. It's the South Atlantic Anomaly!! Regardless of where the anomaly lies, GO COLUMBIA!! ^^^^^ -- ------------------------------------------------------------------------------- ............. | Rikhit Arora And, while with silent, lifting mind I've trod | cheehh@uhupvm1.bitnet The high untrespassed sanctity of space, | cheehh@jane.uh.edu Put out my hand, and touched the face of God. | ~~~~~~~~~~~~~~~~~~ -------------------------------------------------------------------------------
tneff@bfmny0.BFM.COM (Tom Neff) (05/30/90)
In article <18224@well.sf.ca.us> yosef@well.sf.ca.us (Joseph Silva) writes: >Also, how do I post an original message using this darn 'rn' program? From the 'rn' manpage: [ options at the 'What next? [npq]' prompt ] f Submit a followup article. If on a nonexistent article such as the "End of newsgroup" pseudo- article (which you can get to with a '$' command), posts an original article (basenote). Reminder for all users: READ THE DOCUMENTATION for your news and mail software before posting. If you don't have them, ask your sysadmin.
yosef@well.sf.ca.us (Joseph Silva) (05/30/90)
I've heard on the radio (on the way to work...) that the Shuttle Destrorys part (i think .25% was stated) of the Ozone layer each time it is launched. Is this true? Is it cumulative? Also, how do I post an original message using this darn 'rn' program?
henry@utzoo.uucp (Henry Spencer) (06/01/90)
In article <2939@rwthinf.UUCP> dieter@rwthinf.UUCP (Dieter Kreuer) writes: >> This fits with the night launch. From a northern launch site, a night >> launch into low-inclination orbit gives you an orbit with its northern >> end on the night side of the Earth and its southern end on the day side. > >For how long is this orientation of the orbit stable (it is certainly >perturbed by Sun, Moon, atmospheric deceleration, revolution of Earth >around Sun etc.)? ... The major perturbing factor, actually, is the Earth's equatorial bulge. Because of that bulge, the Earth's gravitational field is not (quite) that of a point mass. This produces various effects; in particular, the plane of the orbit rotates slowly around the Earth's axis. The rate of rotation depends on orbital altitude and inclination (for circular orbits; I think it's messier yet for elliptical ones). This is generally on a time scale of months, not days. I can dig up the formula if people are interested. -- As a user I'll take speed over| Henry Spencer at U of Toronto Zoology features any day. -A.Tanenbaum| uunet!attcan!utzoo!henry henry@zoo.toronto.edu