What equipment did the Space Shuttle orbiters carry to support navigation during reentry?
Were there any differences between the individual orbiters in this regard?
3$\begingroup$ I think this should go in the Space Exploration Stack Exchange. $\endgroup$– user71659Apr 19, 2019 at 18:59
1$\begingroup$ If there is a "space-shuttle" tag in the Aviation forum then I would say it is appropriate here. $\endgroup$– Michael HallApr 19, 2019 at 19:06
2$\begingroup$ Navigation in space would be off topic here. If you're asking about navigating during approach and landing, it's on topic here, related to Was the Space Shuttle landing sequence executed manually or automatically? $\endgroup$– foootApr 19, 2019 at 19:50
1$\begingroup$ Do you have a reason for believing Columbia's navigational equipment was different? I gave a general answer below which discusses the orbiters collectively. $\endgroup$– Bret CopelandApr 19, 2019 at 20:07
2$\begingroup$ Also agree with @fooot. Since it was posted here on Aviation, I assume the question is in regards to navigating to the landing site, and I edited it to reflect that. I think it's on-topic. If the OP was asking about space navigation, they can ask a more specific question on Space SE. $\endgroup$– Bret CopelandApr 19, 2019 at 22:16
With the exception of GPS upgrades, I don't believe there were any substantial differences in navigational equipment between the various Space Shuttle Orbiters for most of their operational history.
Each space shuttle had:
- 3 Inertial Measurement Units
- 3 TACAN receivers* see GPS Upgrades
- 4 Barometric Altimeters
- 3 MSBLS Receivers
- 2 Radar Altimeters
- 2 Air Data Probes
- Star Tracker (on-orbit)
- Rendezvous Radar (on-orbit)
There is lots of information about the Shuttle's navigational equipment in the Shuttle Crew Operations Manual.
In the early 1990s, it appeared that TACANs were going to be phased out, so NASA began evaluating GPS as a possible replacement. Space Shuttle Endeavor was the first to have a single GPS receiver installed in 1993, followed by the other shuttles beginning sometime around 1996.
By 2002, each shuttle had 1 GPS and 3 TACAN receivers. The plan was to remove the TACAN receivers and install two additional GPS receivers - resulting in a 3-string GPS system. However, after the loss of Columbia in 2003, it was decided that the Space Shuttle Program would be discontinued in 2010 (later extended to 2011), and therefore it wasn't worth upgrading all three remaining shuttles. Only Endeavor was upgraded. Discovery and Atlantis continued to fly with 3 TACANs and 1 GPS for the remainder of the program.
You can read a lot more about the history of the GPS system here: Operational Use of GPS Navigation for Space Shuttle Entry.
$\begingroup$ thanks a lot :) $\endgroup$– NAYAB SApr 20, 2019 at 11:12
$\begingroup$ nasa.gov/centers/johnson/pdf/… , this link answers it all for me !!! thanks a lot! $\endgroup$– NAYAB SApr 20, 2019 at 15:48