UAE's Hope probe to Mars: How clouds and wind play role in rocket's launch

rocket. launch, UAE Hope probe to Mars

Weather conditions are often difficult to predict several days ahead, especially with the factors affecting rocket launches.

By Nidhal Guessoum

Published: Fri 17 Jul 2020, 6:37 AM

Last updated: Fri 17 Jul 2020, 12:43 PM

The historic launch of the UAE's Hope probe to Mars has been postponed twice due to adverse weather conditions. And since everyone, in the UAE and beyond, has wanted to understand what can rule out a launch, the Mohammad Bin Rashid Space Centre briefly referred to a few issues - unstable weather conditions; heavy clouds at the launch site; and frozen air layer in the atmosphere.
Let me try to explain, in layman's terms, why clouds, winds, low temperatures or other factors can stop a launch from taking place.
One might be surprised to learn that clouds, more specifically 'anvil clouds', can stop a mighty rocket from flying to space; after all, planes fly through clouds and rain every day. In fact, it is lightning that can constitute a major problem, and some types of clouds and air conditions are known to produce electricity in the air, which can then interfere or even shut off some of the rocket electronics, particularly its guidance systems. Icy particles greatly increase the electrification of clouds and the occurrence of lightning. And the flight of the rocket through clouds or cold air layers can often trigger lightning.
Meteorologists will red-flag a launch if thunder conditions exist within 10 or even 20km of the site.
Winds can push the rocket even slightly off course, necessitating corrections that the rocket (with its fuel) may not afford.
The air's temperature affects the performance of the rocket's engine and fuel tanks. Indeed, who can forget the explosion of the space shuttle in 1986, with seven astronauts on board, a disaster caused by the air being too cold for the solid rocket boosters' 'O rings' to seal the tanks properly. Moreover, the engines function best at specific temperature ranges. And finally, strong air turbulence can shake the rocket and its payload (the satellite or probe) and pull apart the fine instruments just slightly, but enough to ruin their performance upon arrival.
Weather conditions are often difficult to predict several days ahead, especially with the factors affecting rocket launches. Last May, the greatly awaited SpaceX launch of the Falcon 9 rocket carrying Nasa astronauts to the space station was scrapped just 17 minutes before the set time. Three days later, it took off successfully.
One space shuttle flight was famously postponed seven times and lifted off successfully on the eighth attempt. Needless to say, it is better to apply an abundance of cautious than to risk a disaster, with astronauts or expensive equipment on board. The Hope probe project is already a success, whether it launches this week, next week, or even two years from now.
(Dr Guessoum holds a PhD in Astrophysics from University of California, USA, and his teaching areas are physics and astronomy.)

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