No SRB problems, No Challenger Disaster

The POD is that in 1977, Morton Thiokol identifies the problems with SRB O-rings that led to the Challenger Disaster and fixes it, or sends NASA a strong warning not to fly in temperatures below, say, 45*F. NASA heeds this warning (or the SRBs are fixed) and thus the space shuttle Challenger is never lost. What are the results?
 
More launches with greater frequency. Probably more support for and earlier instigation of successor reusable systems too. Oh, and launches from Vandenberg as well.

Regards,
Frank
 
Without Challenger, the Shuttle does probably see a lot more flights. 1985 had seen 8 Shuttle flights, 1986 was to have seen 2 in January alone (Challenger being the second). There were if I recall right a number of DoD missions and other flights scheduled for Shuttle that were switched to other launchers because of the return-to-flight delays and safety concerns, some of those stick around and launches like them keep coming.

However, this rate was coming with compromises to safety, with schedule pressures being allowed to outweigh good working of problems. It's possible some kind of other event occurs--perhaps a re-entry tile failure like Columbia. If it doesn't, there's going to need to be more Shuttles. Probably the spare-parts Orbiter (Endeavor OTL, may get different name here) comes to be, and Enterprise may be fitted for flight. OTL it was studied, but Endeavor was cheaper. If the turnaround times and flight rates require more shuttles, then Alt-Endeavor and Enterprise may both see the flight line alongside Challenger, Discovery, Columbia, and Atlantis.

My guess is a continuation of the ramp up, construction and fitting of at least one additional Orbiter to relieve fleet pressures (probably Alt-Endeavor if only one). Eventually, sooner rather than later, a major disaster. However, in the mean time, several missions fly without the RtF delays: the Galileo Jupiter mission, the Ulysses solar study mission (both scheduled for 1986, IIRC), Hubble (on track for October 1986, still with bad optics undetected). Magellan may fly to Venus earlier--I can't find data on when it began construction, so it's 1989 launch may be the earliest it was available.
 
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Still have foam issues.

The second launch after Challenger apparently came close to a Columbia style incident.

It was a military mission and the break up would have occured over the Pacific, leading to all kinds of speculation.
 
One of the reasons why NASA pressured Thiokol into removing the "No Launch" recommendation on the night before the Challenger Disaster was because the new launch criteria would severely restrict the number of launches that the Shuttle could perform. This would have played havoc with NASA's schedule, as mentioned above 1986 was to have been the Shuttle's busiest year to date. In the late 1970's NASA was confidently predicting that the Shuttle would complete 500 missions by 1992, under a 45 degree restriction there is no way that schedule could have been achieved and perhaps Congress would have started asking questions about the entire viability of the Shuttle, the military hated the thing as they were being forced to give up their own fleets of expendable Titans and Atlas, one USAF general acidly remarked that the AIr Force needing to rely on NASA for access to space was like "SAC needing Pan Am to bomb Moscow!" If it was publicly known that the Shuttle couldn't fly as often as the military needed it to then questions as to "Is it really worth it?" would have followed.

The current Shuttle is nothing like the version NASA originally proposed in the late 1960's, which was for a 2 part vehicle with a booster stage and an Orbiter smaller than that which went into service. However Nixon insisted that it be used for launching and recovering military satellites which necessitated a "crossrange capability" which went that the Shuttle would be exposed to atmospheric heating during re-entry for far longer than Apollo or Gemini capsules were. This made the vehicle vulnerable to a Columbia type accident, the original concept wouldn't have been vulnerable to foam strikes.

http://en.wikipedia.org/wiki/Space_Shuttle_design_process

Perhaps if NASA had accepted the 45 degree limit in 1977 it would have been forced to be more realistic about the Shuttle's capabilities and wouldn't have over-promised the programme in the way that it did.
 
While there's no way the Shuttle as it exists can be profitable, a higher launch rate would lower costs somewhat. However, it would seem too high no matter what the actual cost, and there would eventually be a major accident, probably (as has been said) on reentry.

What if, with the Shuttle commercial program looking more successful, NASA succeeds in eliminating the ELV competition?
 
While there's no way the Shuttle as it exists can be profitable, a higher launch rate would lower costs somewhat. However, it would seem too high no matter what the actual cost, and there would eventually be a major accident, probably (as has been said) on reentry.

What if, with the Shuttle commercial program looking more successful, NASA succeeds in eliminating the ELV competition?

I don't see the USAF giving up entirely on ELVs, if only due to the constant need for ICBMs keeping the production lines open. Besides, the Titan IV still had greater GTO capability than Shuttle, because Shuttle didn't use the Centaur stage IOTL, and making a Shuttle orbiter capable of using Centaur would be...inadvisable, to say the least. One would need to cut a hole in the payload bay to run LH2 into the stage, and aborting a launch would be an utter nightmare as you have a Shuttle in an emergency situation with a payload bay full of LH2. Either smaller GTO satellites will be made, or Titan IV will remain in production.
 
Ironically if Challenger hadn't been destroyed then IIRC it's very next flight would have been the first use of Centaur on the Shuttle in order to send the Galileo probe to Jupiter.
 
Ironically if Challenger hadn't been destroyed then IIRC it's very next flight would have been the first use of Centaur on the Shuttle in order to send the Galileo probe to Jupiter.

Oh. Well, in that case, barring a Shuttle disaster in the 1980s and early 1990s, the ELV is demoted to ICBM entirely. Though, as I said earlier, the use of a Centaur opens up a whole new set of possible accidents for the Shuttle.

Another thing to note is that the USAF and/or NASA planned a test of using the Shuttle external tank as a space station, which was shelved after Challenger. So, we might have an earlier, and super-charged Space Station based on the Shuttle ET.
 
A decade of delays ...

IIRC, several ISS module shells were warehoused for the best part of a decade due to the shuttle mishaps. This really annoyed the ESA & European companies who'd built them, trading the modules for access to space. Oh, and the Japanese workshop module to finish off the ISS core was supposed to be on orbit in ~2001...
 
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