Onwards to Uranus and Neptune! Options

[SFJCody]

As soon as MESSENGER gets to Mercury, the most poorly explored planets in the solar system will be Uranus and Neptune. Could this lead to a revival of interest in the ice giants and their retinue, in the same way that the existence of New Horizons is perhaps partly due to the Pluto stamp*?







*via Pluto Fast Flyby and later Pluto Kuiper Express

[Greg Hullender]

Uh, I hope they didn't plan to open the main antenna before firing the Centaur upper stage. :-)

Anyway, I've heard the switch away from the Centaur blamed for the antenna problems. (e.g. Carting the probe around for so long led the lubrication to dry out so the pins didn't release.) But I've heard other explanations too.

Biggest problem with the upper stage (based on reading "Taming Liquid Hydrogen: The Centaur Upper Stage Rocket 1958–2002") was that the shuttle couldn't actually lift the Centaur-G-Prime because the shuttle never achieved its originally planned lift capability. They were talking about throttling up to 109% instead of 104% for the Galileo and Ulysses launches. The astronaut crews were already calling Centaur "the Death Star" before Challenger exploded.

After Challenger, safety changes made the shuttle heavier, and any changes to the Centaur would have made it heavier too. If it was marginal before that, it was hopeless afterwards.

Anyway, the real problem wasn't failing to use the Centaur upper stage; it was using the Shuttle in the first place. Galileo should have been a Titan-Centaur launch, and I don't think there's much dispute over that now. Depending on the shuttle for launching unmanned probes turned out to be a huge mistake. It may have put us as much as 15 years behind where we'd otherwise have been.

But this is old news, long hashed over here. However, if you haven't read it, do have a look at "Taming Hydrogen." It's a great read.

--Greg

[Toma B]

Uh, I hope they didn't plan to open the main antenna before firing the Centaur upper stage.
--Greg

Why not?
Actually that's what I thought they were planing.....I really don't know...