Page 207 - Intro to Space Sciences Spacecraft Applications

Introduction to Space Sciences and Spacecraft Applications
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Table 8-10
United States Launch Vehicles*
Launch Lift-off Low-orbit
Weight (Ibs) Thrust (Ibs) Payload (Ibs)
Delta 426,000 63 1,100 6,000
Atlas 292,600 37 8,000 11,200
Titan 15 19,600 2,920,000 34,050
Shuttle 4,500,000 6,425,000 65,000
*Typical perJormances of the mast common US. launch vehicles are given.

upper stage is a separate rocket which is usually separated from the space-
craft after use.
An important point is that if an upper stage is required, it usually sub-
tracts from the available weight and space for the payload in the launch
vehicle. (Because launch vehicles are multistage rockets, some of the final
stages may be capable of delivering the payload into the desired orbit with-
out the use of an additional upper stage.) Some common upper stages are
the liquid-fueled Centaur (used to send the Viking and Voyager probes
away from the earth), and the solid-fueled Payload Assist Module (PAM)
and Inertial Upper Stage (IUS), both capable of use from the space shuttle.

Ground Sites

Ground sites consist of the spacecraft control facilities, which monitor and
task the system in orbit, and the receiving sites to which the spacecraft may
transmit information for dissemination and use. These are many and varied
and depend on the operator of the spacecraft. At the receiving sites, infor-
mation is collected and put into a form suitable for dissemination to the users.
On the ground is also the most important component of a complete
space system: the system user. In many cases, the user drives the system
design and later operation, as indicated in Table 8- 11 which illustrates the
generic personality of communication, navigation, remote sensing, and
planetary systems. In many instances, the user only accesses the informa-
tion for whatever purpose the spacecraft was designed in the first place.
The task force commander at sea only knows that he has instant access to
his units, via the satellite communications link, and knows his and others’
positions accurately due to the availability of satellite navigation. Weath-
er information in his area of operations is provided by weather processing