Pioneer Spacecraft First Into The Asteroid Belt Options

[Guest_PhilCo126_*]

Launch Pioneer 10 ( 02 March 1972 )
Pioneer 10 entered the Asteroidbelt in July 1972 and emerged in February 1973 ... passing safely as we know ... during 7 months ... Jupiter Flyby in November 1973.
So we had Jovian flyby 7 months after passing Asteroid belt!


Launch Pioneer 11 ( 05 April 1973 )
Pioneer 11 entered the Asteroidbelt in March 1974 and emerged in ??? ( September 1974 ) ... encountered Jupiter in December 1974.
Already 3 months after it cleared the Asteroid belt ?
( went on for flyby of Saturn in August 1979 )

Does someone have exact dates for both Pioneers' milestones ?


Best regards,
Philip

[Guest_BruceMoomaw_*]

Yep -- that's the backup. NASA briefly considered using it for a Jupiter orbiter or an out-of-ecliptic solar orbiter -- that is, as an earlier Ulysses (for which it would have required almost no modification). All those plans vanished, along with so many other interesting space science proposals, into the Shuttle's bottomless and pointless (except for pork enthusiasts) maw. Going to the Museum and seeing it, the third Voyager, the third Viking lander, and the Mariner 10 backup all hanging on the walls (or, in Viking's case, sitting on the floor) and gathering dust is enough to make one think of "Ozymandias".

[dvandorn]

...Going to the Museum and seeing it, the third Voyager, the third Viking lander, and the Mariner 10 backup all hanging on the walls (or, in Viking's case, sitting on the floor) and gathering dust is enough to make one think of "Ozymandias".

"I am become death, the destroyer of worlds"? Surely that's a touch melodramatic, Bruce?

Backup spacecraft are built primarily to ensure that the prime mission will be accomplished -- it's sometimes more wasteful to lose an entire mission than to build a spare spacecraft you can use if the primary one (or, more likely, its booster) fails. Indeed, how many times has a backup spacecraft actually been flown later, on a different mission? I know it's happened a few times, but the majority of backup spacecraft only ever serve the function they were built for -- to back up the primary, and be retired to a museum (or, more often, scrapped) if the primary works properly.

I don't think it's fair to get upset at NASA for failing to fly every backup spacecraft ever built. In most cases, I'm just happy that the primaries were flown. After all, the MERs came awfully close to becoming museum pieces, and they weren't no backups!

Personally, I'd prefer to see missions continue in pairs. We've seen the impact of losing single-spacecraft missions, in whole (MCO, MPL) or in part (Galileo). You have to wait years, sometimes decades, for the primary mission to be re-attempted. Sometimes both spacecraft in a paired mission work, and you get fabulous returns, a la the MERs, Voyagers and Pioneers. But had the Mariner 64 or 71 missions been single-probe flights, backups might not have been ready to fly within the same launch opportunities after the losses of Mariners 3 and 8.

I think it's *always* better to see a third spacecraft in a museum, along with displays of the results of the *two* flight vehicles that completed their missions. Seeing a backup vehicle from a mission that failed in a museum -- now *that* is a tragedy.

-the other Doug

[odave]

I think he was thinking more along the lines of "Look upon my works, ye Mighty, and despair"

I agree with Other Doug: Given that the science return from those missions is certainly a net positive, the feeling for me would be "wouldn't it have been great if", rather than despair.