Meteorological Support for Space Operations Review and Recommendations (1988) / Chapter Skim
Currently Skimming:
SENSITIVITY OF THE SPACE PROGRAM TO WEATHER ELEMENTS
SENSITIVITY OF THE SPACE PROGRAM TO WEATHER ELEMENTS
Pages 9-19
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 9... ...
At 36.5 seconds into the flight, and again at 52 seconds, major atmospheric electrical disturbances occurred that were subsequently attributed to vehicle-triggered lightning. Temporary disruptions of normal operations included the loss of attitude reference by the inertial platform in the spacecraft, illumination of many warning lights and alarms in the crew compartment, disconnection of the electronic circuitry to three fuel cells, loss of communication, and disturbances to the timing system, clocks, and other instrumentation.
|
From page 10... ...
Space vehicle encounters with adverse weather conditions have been quite limited over the 30-year history of the space program, owing to a judicious selection of launch days, landing sites that usually favor benign weather environments, and the relatively short periods of time when the flight is in the weather-bearing layers of the atmosphere. The accumulated "exposure" time, amounting to a few minutes during each launch and up to an hour on manned reentry and landing, makes the total base of weather experience a few days at most.
|
From page 11... ...
A similar experience by NASA astronauts flying a NASA T-38A on February 24, 1987, in wintertime stratiform clouds near Los Alamitos Army Aviation Facility, California, shows that triggered lightning is pervasive. Since the avoidance and hardening options have practical limits that fall short of ensuring total weather "immunity" and since modification of the weather does not appear to be practical at this time, the panel advocates improving weather observing and forecasting capabilities.
|
From page 12... ...
This will also provide the background for the subsequent chapters, which will map a strategy for implementing an effective, state-of-the-science weather observing and forecasting system. WEATHER FACTORS IMPORTANT FOR SPACE OPERATIONS Weather elements influence all phases of space operations, from mission planning through actual launch, booster rocket recovery (in the case of the Space Shuttle)
|
From page 13... ...
could cause the vehicle to deviate from course or break apart. Aerodynamic loads, from wind shears comparable to the largest previously encountered during launch and from vehicle response maneuvers, may have contributed to the final failure of the O-ring seals.*
|
From page 14... ...
More obvious weather threats such as thunderstorm-related wind shears and lightning present an even greater risk to the spacecraft during the landing phase. Rescne and Recovery at Sea Booster rockets from the Space Shuttle normally fall into the sea and are recovered by ship.
|
From page 15... ...
Unfortunately, it appeared to the panel that there is only crude quantitative data regarding the risk posed by some weather hazards, such as the values of cloud electric fields that are capable of producing spacecraft-triggered lightning. One dangerous byproduct of inadequate information on weather element-risk relationships may be a tendency for the launch director to issue waivers of launch criteria when conditions seem to be marginal; on average, two waivers have been issued for each shuttle launch to date.
|
From page 16... ...
Most of the data needed for an effective climatology of this type do not yet exist and require obtaining data sets from new sensors. Among the data needed are the types and sizes of precipitation elements in various kinds of clouds, the electrical fields within and near detached anvils and a variety of other cloud types, the electric fields that are required to produce triggered lightning, and the magnitude of wind variations on a variety of time scales.
|
From page 17... ...
:1134-1140.) are needed that characterize the triggered lightning hazard, electric fields within and near a variety of cloud types, precipitation types and sizes, and short-term wind variability.
|
From page 18... ...
wedges of high wind speeds with strong vertical shears, such as illustrated in Figure 2, are typically associated with disturbed weather and may not have been adequately represented in a sample biased toward warm, fair weather occasions. An accelerated launch schedule will tend to require launches on some less-than-perfect occasions, and the present jimsphere pairs underestimate the wind shear hazard on those types of days.
|
From page 19... ...
It is especially critical that the data base include cases of clear skies immediately following cold front passage, where strong turbulent jet streaks are often found. The jmiHphere-pair data base should be expanded, especially during the whiter season, and should be supplemented by wind profiler data.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.