Hot answers tagged

133

I believe the discovery was made by orbiting satellite, but I'm not sure which one. That is not the case. Look at the author affiliation for the article to which you linked. The three authors of that paper were from the British Antarctic Survey. These scientists were part of a larger expedition to Antarctica. They pointed a cheap instrument (extremely cheap ...


36

I think you got it wrong: R-7 launches sometimes are also postponed due to weather. Just to name few examples: 18 December 2018, 9 March 2018, 22 April 2016 - Kouru; March 22, 2016 - Baikonur, 2 october 2011 - Plesetsk. These are just few examples of Soyuz launches delayed to weather conditions. R-7 is actually not especially structurally strong, it's a bad ...


33

Part of this is also discussed in the How can Mars have dust storms with such a thin atmosphere? thread, but yes it would be abrasive, and direct evidence for this can be appreciated in all kinds of aeolian formations on the Martian surface, like the dunes of the Nili Patera region or the ones in the Lyot Crater, just to name a few of the most well know ...


29

There is a huge difference between the US and Russian launchers, in terms of tolerance for weather. Additionally, different launchers have different tolerances. The Russians launch from Baikanour, which is kind crazy weather wise, and cold, and snow, and other weather is much more common, so they designed from the get go for weather tolerance. It probably ...


29

Note: This answer is based on a source from 2001. It provides a lot of background as a historical overview, but it does not take into account recent changes in the program. Please review the end of Organic Marble's answer for a fuller perspective. Initially, it began as a temporary program. In the late 1950s, the US military needed accurate and timely ...


28

This question is based on several serious misconceptions. R-7 launches never get postponed due to weather. Actually, they do. "The launch of the Soyuz 2-1A modernized carrier rocket, scheduled for Wednesday evening, has been put off again, this time due to bad weather conditions at an altitude of more than 11 kilometers," the source said. The only ICBMs ...


25

Short answer: Yes. Mars is not windy enough to properly wave most flags. Long answer: In storm conditions, a flag constructed out of a very light material would be able to properly wave. If we take a standard flag, say 3'x5' that's made of 200g Nylon $\ell= 1.5$ meters $h_f = 0.9$ meters $W = A * 0.2 * g_{Mars}$, $W = 1$ Newton Going off the calculations ...


23

The Iridium 7 mission, Jul 25, 2018 gives a partial practical answer. Throughout the webcast John Innsbruker reminded everyone that conditions for landing in the Pacific for the JRTI (Just Read The Instructions) ASDS were the worst they have ever tried to land in. Yet they continued the launch when they had a back up launch window 23:55 hours later. This ...


20

Are launch windows to Mars avoided if they result in landings during dust storm season? No. It's pretty well known that the gusts of wind on Mars are relatively harmless to a person standing on Mars (one of the big things the movie The Martian got wrong). Even though winds on Mars could reach up to 130 km/h, the atmosphere is very thin and thus does not ...


19

Certainly a reasonable question. A possibly useful mental model is to spin a bucket of water in some form. Initially only the surface layers will spin but each layer transfers motion to the next layer in and eventually the entity of the mass is spinning in a steady state. Similarly with the atmosphere over geologic time scales the atmosphere is spinning with ...


18

Mostly a product of two environmental factors, I would wager: Lack of in-air humidity or liquid water on the ground keeping dust fine grained and not sticking together to form larger mass particles, and Relatively low surface gravity of roughly 1:2.6 when compared to the sea-level gravity on the Earth keeping them suspended in atmosphere for longer periods ...


18

The specific needs of the military may not be served by civilian weather satellites. Specifically, the DMSP started as a classified program that supported the Corona spy satellite program. Its purpose was to predict cloud cover over foreign countries so that the expendable film in the Corona satellites would not be used up taking pictures of the tops of ...


18

The orbiters were not allowed to fly through precipitation on landing for the following reasons: The orbiter is not to encounter precipitation on any approach due to decreased visibility, damage to the TPS, and the potential for triggered lightning. Undesirable aspects of thunderstorms include rain (TPS, structure), hail (TPS, structure, control), severe ...


16

It's mainly just bad luck. There is really only one relatively common weather condition that you don't want to launch a rocket into and that's a thunderstorm. Granted, high winds can also be problematic. And it should go without saying that you don't want to launch during a hurricane or tornado. Rockets are perfectly capable of launching directly into a ...


16

Lightning and wind are the primary weather concerns that preclude rocket launch. A rocket's control system needs to compensate for lots of un-modeled or difficult to model factors. For example, uncertainty in mass properties, engine performance, mechanical alignments, errors in inertial measurement units (IMU), gyroscopes, GPS, etc. If any of these errors ...


16

To quickly summarise the answer: Nimbus 7 was the satellite involved - but it wasn't first. The ozone hole did not substantially materialise before the early-1980s - in retrospect the decline was visible, as this graph shows, but the catastrophic drop hadn't happened yet. Nimbus 7 was the first satellite (I think?) to carry an ozone spectrophotometer, which ...


14

I can provide details only for the Space Shuttle. 1) Up to 155,000 feet - the approximate altitude of SRB separation - the end of first stage flight. Here are example wind plots (from here) [Note the error on the Y axis label - it should be meters, not km] a. Jet stream winds and associated wind shear b. Sinusoidal variation in wind with altitude c. ...


14

The lower atmosphere must rotate with the earth because of friction---at least the very bottom of it. That is true, but only at the very, very bottom of the Earth's atmosphere, perhaps the last few millimeters. There are winds, after all. The trade winds and the prevailing westerlies (along with the discovery of how to beat against the wind) resulted in the ...


13

What are the complications which would occur during a rocket launch when it rains? In addition to the issues raised by geoffc, another is that rain (or rather the rain clouds) obscure visibility of the rocket. Two key goals of launching from a US-based launch site are that the launch should not present a hazard to the US public at large, and perhaps even ...


12

Structural strength is not the only factor in rockets dealing with weather, they are already designed to withstand many Gs of acceleration carrying tons of explosive fuel. Flying through a cloud isn't going to hurt them. Although there delays due to winds launches are postponed because of weather for several other reasons, including: Wind: High winds could ...


11

Why are rocket launches so sensitive to weather? It could make the difference between an O-ring failing, or not. In the Challenger disaster.. Disintegration of the vehicle began after an O-ring seal in its right solid rocket booster (SRB) failed at liftoff. The O-ring failure caused a breach in the SRB joint it sealed, allowing pressurized hot gas from ...


11

Lightning has been observed in Mars. However, this is 'dry' lightning, unrelated to precipitation. This was described in the paper Emission of non-thermal microwave radiation by a Martian dust storm by Christopher Ruf and others.


11

There are no horse latitudes on Venus, only equatorial doldrums and polar fronts / collars. Convection driven Hadley cells on Venus stretch to ±60° in latitude from the intertropical convergence zone to North and South polar collars, so no subtropical latitudes high pressure areas. From Wikipedia on Atmosphere of Venus - Circulation: This is quite a bit ...


11

This is a bit tricky to answer, as we don't have perfect global weather from Mars. But as can be seen from the images at this site, it will be a low lying area near the the equator. If I had to venture, I would say the sourthern part of Syrtis Major, but I haven't seen a high enough detailed graph to definitively answer this question.


11

From a mechanical, engineering view, having a brush on a robotic arm to clean the solar panel is more favorable, than rotating the panel. Having a current transfer between the rotating solar panel and the standing probe is highly problematic and would cause likely more problems, than the dust itself. Note, although that dust played a role in the end of life ...


10

There are a number of ways. Basically, you can either get a global record, or a record from a spacecraft. Curiosity provides us with the clearest cut version, available from its website. Mars Climate Sounder, on MRO, shows daily maps of the temperature as recorded from MRO. That data isn't readily available, but can be found from the Planetary Data System.


10

The answer is that the solar radiation heats the thin atmosphere of Mars but hot air rises up and it also lift its small dust (since Mars has low surface gravity of 3.711 $m/s^2$ they are almost weightless) and dust-storms begin to form, swirling at great speeds due to the thin atmosphere probably due to formation of different pressure in the atmosphere (...


10

HURCON levels range from I to V and are properly defined by the USAF. The KSC uses these levels as well, as outlined by the "KENNEDY SPACE CENTER AND CAPE CANAVERAL AIR FORCE STATION CONSOLIDATED COMPREHENSIVE EMERGENCY MANAGEMENT PLAN (CCEMP)". The plan establishes that both the space center and air force base are subject to very similar threats and ...


9

The Space Review has an entire article devoted to such failures. I've also found a few other. Missions where wind was, or was almost, a failure, include the following: Atlas Centaur AC-67 FLTSATCOM 6- Weather was go until a last minute weather balloon was launched, not according to plan. The balloon found the winds were unacceptable for launch a mere 15 ...


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