Author Topic: Challenger STS-51L  (Read 86418 times)

Offline James Lowe1

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Re: Challenger STS-51L
« Reply #40 on: 12/10/2005 08:58 PM »
Quote
anik - 10/12/2005  9:48 AM

P.S.: Between Challenger (61-F) and Atlantis (61-G) launches were 5 days!

So we'd of had TWO orbiters in space at the same time??

Offline Mark Max Q

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Re: Challenger STS-51L
« Reply #41 on: 12/10/2005 11:15 PM »
Looks like it. I cannot think of any reason an Orbiter would be up there for less than five days. Wow.

Offline Spacely

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Re: Challenger STS-51L
« Reply #42 on: 12/11/2005 04:19 AM »
Does anybody know what the Jupiter ETA was for Galileo had it been launched in '86 with the Centaur stage?

Offline Ben E

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Re: Challenger STS-51L
« Reply #43 on: 12/11/2005 06:15 AM »
I think Galileo's Jupiter ETA would have been about two years later in 1988. It was pretty quick compared to IUS.

No, 61F and 61G wouldn't have been in orbit at the same time. I don't think the Mission Control, existing TDRS and tracking capabilities could have handled that. Both missions were scheduled as two-day missions, because the heavy Centaur and Ulysses/Galileo meant that consumables/equipment/supplies/crew number had to kept to a minimum. I wrote to Dave Hilmers about it back in 1991 and he told me that, ordinarily, four days is the shortest duration for a planned Shuttle mission but that these two in particular were shorter because of weight considerations.

Interestingly, they were also destined for the lowest Shuttle orbits of all time - 105 nautical miles, simply because Centaur was so heavy and they needed the SRB/orbiter performance to simply get it up there.

Have a look at my Death Stars article in Features on this site for a bit more info.




Offline SimonShuttle

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Re: Challenger STS-51L
« Reply #44 on: 12/11/2005 11:52 AM »
Ah that's interesting. Yikes, nothing like taking up heavy dangerous stuff in your payload!

http://www.nasaspaceflight.com/content/?id=3943

Offline psloss

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Re: Challenger STS-51L
« Reply #45 on: 12/11/2005 12:28 PM »
Another "fun" thing about the shuttle/Centaur flights is that they were for a long time planned to use 109% throttles on the main engines (for the heavy payload); I don't know where that stood at the time of the Challenger disaster, but I can imagine that John Young wasn't that confident in the results of the "full power level" ground testing at the time.  I think there were people worried the engines as much as the boosters at the time, perhaps more.

Offline Spacely

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Re: Challenger STS-51L
« Reply #46 on: 12/11/2005 06:27 PM »
After reading that article, I'm fairly certain that if Challenger didn't happen, a Centaur-related disaster would have. Let's also not forget that in a universe where the Challenger doesn't explode, all EELV rocket lines would eventually be shut down, and all payloads put on shuttles. With more payloads on more shuttles, and more shuttle flights, it really would have been only a matter of time.

On the other hand...

If that inevitable shuttle disaster didn't end up happening until, say, 1996, instead of 1986, there's a decent chance that 10+ years of 15 shuttle flights a year may have had us a couple new military-only shuttles and a pretty cool Space Station Freedom.

Of course, in that scenario, I have a feeling solar system exploration budgets would have been sliced and diced and we would not have anywhere close to the current Mars program, Cassini, or the robust "Discovery" class missions. It's all so hard to predict!

Offline Justin Space

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Re: Challenger STS-51L
« Reply #47 on: 12/11/2005 06:40 PM »
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Spacely - 11/12/2005  7:27 PM

If that inevitable shuttle disaster didn't end up happening until, say, 1996, instead of 1986, there's a decent chance that 10+ years of 15 shuttle flights a year may have had us a couple new military-only shuttles and a pretty cool Space Station Freedom.

Of course, in that scenario, I have a feeling solar system exploration budgets would have been sliced and diced and we would not have anywhere close to the current Mars program, Cassini, or the robust "Discovery" class missions. It's all so hard to predict!

One thing we couldn't of stopped was the cooling of the Cold War.

Heaven's forbid, but if it all kicks off with China - and they go big on space, then I have a feeling that would open up a few options.

Offline STS Tony

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Re: Challenger STS-51L
« Reply #48 on: 12/11/2005 07:56 PM »
Also prestige. It would be ironic if after beating the Red Machine of the Soviet Union to the Moon, we then lose to a weaker Russia to Mars.

Offline Ben E

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Re: Challenger STS-51L
« Reply #49 on: 12/11/2005 11:05 PM »
Sticking with the Challenger and Vandenberg themes, is there any reason why some military flights HAD to be launched from California? I know they were mostly headed for polar orbits and needed to head south, but what difference would it have made if they'd headed for the poles down the east (KSC) or west (Vandenberg) seaboards?

Picking up on an earlier comment about the inevitability of another disaster, certainly there was a high risk on the 61F and 61G launches. If the Centaur missions had just been Ulysses and Galileo, the odds might have been okay, but I believe Magellan was originally pencilled-in for a Centaur launch in 1988 and so too were a few polar-orbiting and DoD satellites out of Vandenberg. Plus, of course, there was the inherently dangerous Vandenberg site itself, which had already turned up potential problems with its flame trench, soundwaves reflecting off the surrounding mountains and those dodgy-sounding filament-wound SRBs.

I shudder to admit it, but even without 51L, I think a disaster was not far off.

Online DaveS

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Re: Challenger STS-51L
« Reply #50 on: 12/11/2005 11:22 PM »
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Ben E - 12/12/2005  1:05 AM
 but what difference would it have made if they'd headed for the poles down the east (KSC) or west (Vandenberg) seaboards?
Going south from KSC makes the flightpath cross inhabited land masses and if something goes wrong during ascent debris could fall on foreign soil and make the recovery and investigation much harder. Launching south  from Vandenberg avoids this as there's not much inhabited land masses in the flightpath. This why all polar orbit missions no matter if it is on the shuttle or on an conventional ELV launches from Vandenberg.
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Offline Super George

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Re: Challenger STS-51L
« Reply #51 on: 12/12/2005 07:43 PM »
Have I got this right be thinking a launch from KSC goes to the East, and the Vandenberg Shuttle missions would have gone to the West, as to the South is just rockets?

Offline psloss

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Re: Challenger STS-51L
« Reply #52 on: 12/12/2005 08:25 PM »
Perhaps someone here knows of a better reproduction than this, but it's still useful:
http://stsliftoff.com/Documents/newsref/bigimages/launch_sites_8.jpg

(I believe that STS-36 went to 62 degrees inclination from KSC with a dogleg maneuver, I'm assuming after the trajectory cleared populated areas during second stage...)

Offline Launch Fan

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Re: Challenger STS-51L
« Reply #53 on: 12/12/2005 10:59 PM »
And Discovery was going to have a new home in California? Reading the story about the Centuar launch, it seems to intimate this?

Offline Super George

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Re: Challenger STS-51L
« Reply #54 on: 12/12/2005 11:24 PM »
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psloss - 12/12/2005  3:25 PM

Perhaps someone here knows of a better reproduction than this, but it's still useful:
http://stsliftoff.com/Documents/newsref/bigimages/launch_sites_8.jpg

(I believe that STS-36 went to 62 degrees inclination from KSC with a dogleg maneuver, I'm assuming after the trajectory cleared populated areas during second stage...)

Thank you! Never seen any map like that before. Very cool :)

Offline ADC9

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Re: Challenger STS-51L
« Reply #55 on: 12/13/2005 12:09 AM »
Yes, very nice image. I wasn't actually aware they could launch Westerly?

Offline psloss

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Re: Challenger STS-51L
« Reply #56 on: 12/13/2005 12:53 AM »
Quote
Launch Fan - 12/12/2005  6:59 PM

And Discovery was going to have a new home in California? Reading the story about the Centuar launch, it seems to intimate this?
Yes...well, eventually.  If I recall correctly, for the first few Vandenberg missions the Orbiter Maintenance and Checkout Facility (OMCF) at North Vandenberg wasn't ready to fully process the orbiter, so I believe after each of the first few missions Discovery was going to go back to KSC for post-flight servicing and whatever work needed to be done there and then ferried to the OMCF at Vandenberg to finish processing and transport to Slick Six for pad processing.

Philip Sloss

Offline GregM

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Re: Challenger STS-51L
« Reply #57 on: 12/13/2005 04:02 AM »
If memory serves me correctly, Discovery was paid for by the DOD. One must remember at the time that this was the Reagan years. The military was riding very high, and had a seemingly limitless hi-tech future (and budget). The cold war was at it’s modern hi-tech peak, not to mention peak tensions. DOD had many of their people installed in key NASA positions , despite the fact that NASA was supposed to be a civilian agency. I believe in fact that the person running the shuttle program at the time was an active-duty Air Force General by the name of Jim Abramson. There were many in the DOD who were still bitter about repeated attempts to form a separate DOD manned spaceflight program in the 60’s ending in cancellation. Two “blue” DOD manned space programs, the Dyna-Soar and MOL were cancelled well into the program’s developments in the 60’s. A “Blue” astronaut corps had been selected and trained (I believe that Abramson was one of those astronauts), launch systems were being developed (based on Titan 3), spacecraft were being developed, launch facilities were being built (slick 6). The programs kept getting cancelled prior to a first flight however.

Now with the shuttle, the DOD was going to get between one quarter and one third of all shuttle flights eventually. The dream of some in the DOD to have a separate manned space program of their own was finally going to happen. To support this effort, there was again  going to be a separate DOD astronaut corps, a dedicated DOD shuttle orbiter, a dedicated DOD shuttle launch, landing, and orbiter processing facility, and a separate DOD mission control room at JSC in Houston. In essence, it was going to be a completely separate DOD  shuttle program operating independently within the existing NASA program. Most of the flights would be polar-orbit flights operating out of VAFB – flying black NSC stuff and SDI stuff (such as Teal Ruby), with occasional blue payloads requiring geosynchronous orbits still launching out of KSC. The DOD poured billions and billions into the “Blue Shuttle” program as it was called at the time. The program was so prestigious that the Secretary of the Air Force, Pete Alderich, was to fly as a crew member on the first or second Vandenburg blue shuttle flight. The Soviet development of Buran was a direct response to the Blue Shuttle program.

As for the Centaur upper stage, the only application that NASA really had for it was for launching the "flagship” interplanetary probes – of which there were very few (maybe 4 in 10 years). Most Centaur flights, had they gone on successfully, would have ultimately been on blue shuttle flights.

Of course with 51-L, it all fell apart. The anti-manned spaceflight faction within the DOD correctly saw the event as the opportunity to get the DOD out of the shuttle business, which it did. There were still serious technical and safety challenges at the VAFB shuttle complex (slick 6) that required rectification prior to a launch, and the Centaur program was always on less than a solid technical footing. The problems may have been eventually solved – but at yet greater cost than the huge outlay already spent by the federal government on the projects.

When the return to flight came in 1988, NASA flew the DOD payloads that were specifically designed for the shuttle out of KSC instead of Vandenburg as originally intended, with some compromises to the payloads designed for polar orbits. With that, the DOD’s expensive flirtation with manned spaceflight ended (at least as far as we know – there may well be black programs today that for all practical purposes are spaceflight programs).

If things had gone differently however, and there was no Challenger mishap, and the Blue Shuttle program got up and running successfully - we would have a VERY different space program today.

Offline Rocket Guy

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Re: Challenger STS-51L
« Reply #58 on: 12/13/2005 04:24 AM »
Quote
psloss - 12/12/2005  4:25 PM

Perhaps someone here knows of a better reproduction than this, but it's still useful:
http://stsliftoff.com/Documents/newsref/bigimages/launch_sites_8.jpg

(I believe that STS-36 went to 62 degrees inclination from KSC with a dogleg maneuver, I'm assuming after the trajectory cleared populated areas during second stage...)

I don't know who made that map but it is totally inaccurate. 28 is more southerly than 39. 39 degress goes NE. Second, those SRB impact lines are WAY WAY too far out!

Offline Rocket Guy

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Re: Challenger STS-51L
« Reply #59 on: 12/13/2005 04:27 AM »
Quote
ADC9 - 12/12/2005  8:09 PM

Yes, very nice image. I wasn't actually aware they could launch Westerly?

You can launch westerly, but in this case we are referring to sun-sync orbits which are more than 90 degrees (south southwest)...from 91 up to about 105 degrees.

While the Shuttle could not do it, they can launch westerly with the right rocket and small payload. It's all a matter of having enough fuel and thrust to push a payload into orbit with the Earth's rotational speed subtracted instead of added.

Edit: misspelled westerly 'weatherly'

Most polar orbits are retrograde by a few degrees, by the way.

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