The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

270 MECO (main engine cutoff)
recorder, and a parallel computer system. MDS-1 was
launched by a NASDA (National Space Development
Agency) H-2A rocket on February 4, 2002, into a geostationary
transfer orbit (500 × 35,696 km × 28.5°).
MECO (main engine cutoff)
The time at which the main engines of a launch vehicle,
or launch vehicle stage, are commanded to stop firing.
MECO typically involves a sequence of events, including
throttling back the engines before actual cutoff. For
example, the MECO sequence for the Space Shuttle
begins about 10 seconds before cutoff. About three seconds
later, the Space Shuttle Main Engines (SSMEs) are
commanded to begin throttling back at intervals of 10%
thrust per second until they reach a thrust of 65% of
rated power, called minimum power. Minimum power is
maintained for just under seven seconds, then the
SSMEs shut down.
Mentor
A fourth-generation ELINT (electronic intelligence)
satellite launched for the CIA. See also Mercury-
ELINT, SB-WASS, and Trumpet.
Mercury Seven The Project Mercury
astronauts: front row, left to right, Walter
Schirra, Donald Slayton, John Glenn,
and Scott Carpenter; back row, Alan
Shepard, Virgil Grissom, and Gordon
Cooper. NASA
MEO (medium Earth orbit)
An orbit that is intermediate in altitude between that of
LEO (low Earth orbit) and GSO (geostationary orbit) at
35,900 km.
Mercury, Project
See article, pages 271–275.
Mercury Seven
The original group of seven American astronauts selected
on April 9, 1959, for the Mercury program. It included
Scott Carpenter, Gordon Cooper, John Glenn, Virgil
Grissom, Walter Schirra, Alan Shepard, and Donald
“Deke” Slayton. All but Slayton actually flew a Mercury
mission. The maximum age for candidate Mercury astronauts
was set at 40, the maximum height at 5 ft. 11 in.
(1.80 m), and the maximum weight at 180 lb. (81.6 kg).
The first check of military test pilot records revealed that
508 test pilots met the basic astronaut requirements.
With suggestions from commanding officers, this list was
first cut to 110 and then, with the help of trainers and
instructors who had brought these men up to flight
(continued on page 275)