Thrust From United States of America, joined Sep 2003, 2691 posts, RR: 9 Posted (3 years 8 months 3 weeks 6 days 10 hours ago) and read 4270 times:
Hi there. I've been observing videos of shuttle launches in the early 1980s, post-Challenger, and post-Columbia. I've noticed that earlier shuttle missions broke the speed of sound slightly later than the final shuttle missions, and also separated from the solid rocket boosters at lower speeds than the earlier shuttle missions. I know for a fact that the solid rocket boosters gained weight after the Challenger disaster due to the addition of a third o-ring, but I don't know how a much a difference that extra weight made. I also know the shuttle received numerous upgrades over the years, example, a glass cockpit over a traditional one, etc. I observed these changes by timing the clocks on the videos...obviously that is not the best way to do it, but I was hoping somebody on here could give me something that would tell me if my eyes are deceiving me or not. Thanks.
BigSaabowski From United States of America, joined Jul 2008, 169 posts, RR: 0
Reply 3, posted (3 years 8 months 3 weeks 6 days 5 hours ago) and read 4161 times:
You may be comparing apples to .....pears.
Many of the later missions were launched into high-inclination orbits (for the purpose of servicing the ISS), which have different energy requirements than a low-inclination orbit, and that alters the flight profile.
HaveBlue From United States of America, joined Jan 2004, 2152 posts, RR: 1
Reply 4, posted (3 years 8 months 3 weeks 6 days 4 hours ago) and read 4145 times:
Quoting Thrust (Thread starter): I've noticed that earlier shuttle missions broke the speed of sound slightly later than the final shuttle missions,
Quoting ZANL188 (Reply 1): By what means are you using the video to determine velocity?
Good question, as to how are you determining that? What immediately came to my mind was are you using the visible 'shockwave' seen as it ascends? You can and do see that wave at speeds well below actual supersonic depending on conditions, and whether you see it at all or not is largely affected by humidity in the air, which is often abundant in FL and makes for exciting 'supersonic looking' airshow pictures