Path: utzoo!attcan!uunet!aplcen!haven!udel!burdvax!techpubs
From: techpubs@PRC.Unisys.COM (Technical Pub. Vince Short)
Newsgroups: sci.space.shuttle
Subject: Gallileo vs Ulysses orbits to Jupiter
Message-ID: <15004@burdvax.PRC.Unisys.COM>
Date: 17 Sep 90 19:16:47 GMT
References: <1990Sep16.013630.22643@news.arc.nasa.gov>
Organization: Unisys Corporation, Paoli Research Center; Paoli, PA
Lines: 30

In the STS-41 press kit, we find that:

". . .  After being deployed from Discovery . . .  a two-stage Inertial 
Upper Stage and a single-stage Payload Assist Module will boost Ulysses 
on a trajectory that will take it to Jupiter in 16 months.  . . ."

This is a direct transfer orbit to Jupiter.  

My question: if this can be done for Ulysses (direct transfer orbit 
to Jupiter), why couldn't it have been done for Gallileo which 
was sent to Jupiter via a complex Venus-Earth-Earth gravity assist orbit.

Gallileo was launched via Atlantis during mission STS-34 in October 1989. 
However, it only used an Inertial Upper Stage (IUS) without the "assist" 
of a Payload Assist Module (PAM) after the IUS burns.  

Why no PAM on Gallileo? Is Gallileo so much heavier than Ulysses? Anyone 
have any numbers (masses, delta v's, etc) for the craft and their orbits? 
Was there just no way to attach a PAM between the IUS and Gallileo? 
Or what? 


                                                                            
                                         Joseph M. Fedock                   
                                         Technical Publications             
                                         Unisys Corporation                 
                                         DS/EISG/VFL            
                                         Paoli, PA 19301                    
                                         (215) 648-2495                     
                                         techpubs@burdvax.PRC.Unisys.COM