# Tag Info

112

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 ...

27

What is the name of this line or this area? line A term for the line that's perfectly usable for this purpose is "horizon". The horizon, the line line separating the land from the sky, would be the green line in your image. Anything closer than the horizon will be visible to the spacecraft. area Note also that even though the area appears to have ...

21

What is the name of this line or this area? Typically, the part of the earth's surface that a satellite can view at any moment is known as its footprint, a term frequently used for remote sensing satellites and communications satellites. SE's answer about the horizon applies if the satellite is viewing the entire visible portion of the globe at once. As ...

17

It was a secondary payload launched along with the first operational Transit navigation satellite (Transit 5BN-1) and was named, mundanely enough, Transit 5E-1. Mission goals were Measure omnidirectional flux of protons and electrons above certain threshold energies in order to determine the temporal variations in the radiation environment. Verify ...

15

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

Zenit flights continued until 1994 http://www.zarya.info/Diaries/Zenit/Zenitindex.php

13

The visual acuity of a healthy human eye is about 1 arcminute (a full circle is 360°, 1 ° is divided into 60 arcminutes). A football with a diameter of 220 mm at a distance of about 775 m subtends an angle of 1 arcminute. Or a tiny object of 0.2908 mm at a distance of 1 m. The Earth diameter is 12742 km. So the distance is 43,8 million km or 0.293 AU as @...

12

The earliest mention of the northern lights that I was able to find is the memories of the Voskhod-1 crew. «Наибольшее впечатление на всех нас произвело полярное сияние, которое нам удалось наблюдать в районе Антарктиды за несколько минут перед выходом из тени. Картина была такая: горизонт, затем тёмное небо, затем верхний слой яркости, подсвеченной луной, ...

10

Your comment on this answer has, I think, led me to understand what you are really asking about. What I am saying is that, presuming the inclination to be ZERO (Plane of orbit parallel to the equatorial plane), the entire plane keeps shifting from pole to pole - parallel to the equatorial plane. You want to move the orbit like this: If that is the right ...

8

Inclination changes are very expensive in terms of delta V/fuel. To do a 90 degree plane change you are thrusting against your current ~7 kilometer a second velocity to bring it to zero and also adding thrust to get a ~7 kilometer per second velocity in the new orbital plane. This is more than it took to get into orbit in the first place, and would require a ...

7

Although a little vexing, the GIF below and the answer it comes from shows that even fixed orbit will eventually pass over all places on a body that rotates underneath it that are at any latitude smaller than the inclination. That being said you have to choose an altitude that spread them out evenly so that you don't have to wait a very long time. That being ...

5

NICER, on the ISS, uses a combination of passive damping and active control to achieve pointing within 66 arc seconds of the target 99% of the time. As far as I know, no ISS astronomical payload has achieved better pointing than this. The NICER ISS payload consists of an X-ray timing instrument (XTI) as well as supporting hardware that points the XTI at ...

5

Short version: you have to read the Algorithm Theoretical Basis Documents (ATBD), conveniently collected at https://clasp-research.engin.umich.edu/missions/cygnss/data-products.php . All of them. They are too long (143 pages in total, by my count) to do them justice here, but I will try to give you a whirlwind tour. At the most basic, the satellite ...

3

Ozone depletion first came up as a publicly visible issue around 1976. Up to that time, almost nobody was aware that ozone was an issue at all, so there hadn't been a big push to build satellites to observe it. Even when ozone depletion did become known, some greeted it with skepticism (especially people making money off of selling aerosols, of course). For ...

3

The choice of an inclination of 51.7° for Salyut 6 (and all other space stations with Russian contribution) is straight forward: It's the lowest inclination that can be reached from Baikonur without crossing the border of China during launch. The low inclination allows for the largest possible payloads due to the additional boost from Earth rotation. All ...

2

I am not sure what you mean by "ocean roughness", but the CYGNSS products are wind speed and Mean Square Slope (MSS). You can read the retrieval algorithms here (pag 47) and here (page 5) respectively.

2

There’s a 2017 federal “Sources Sought” for launch services for TROPICS. The relevant part is: Therefore, 6 to 8 TROPICS CubeSats will be placed in a constellation formation as described in the three scenarios included in the attached document. All of the CubeSats are identical and must be placed into their operational orbit within 60-days (first ...

2

ICESAT-2 The POD team developed the ICESat-2 orbit with the initial requirements of: (1) a 92°inclination orbit for coverage of polar ice and sea ice while still producing orbit-crossings for altimeter cross-over observations, (2) a frozen orbit to limit altitude variation at any given latitude in order to maintain beam pattern geometry on the surface, (3) ...

2

Space-Track has only tracked the object intermittently. They are not, in general, a reliable source for high-flying objects with orbital periods of about two days or more. I am not entirely sure why. Radar is poorly suited to such tracking (effectiveness drops off as the fourth power of distance, instead of inverse-square as it does for optical ...

1

The answer is that the two telescopes have different focal lengths and that focal length and mirror size are parameters that can be independently adjusted (there are obviously other tradeoffs to do with resolution and focal ratio). Here's a description of why. Here is a rather terrible diagram of a simplified Newtonian reflector – I've simplified it just by ...

1

In this answer dimensionless gravitational multipolar moments for the Earth are given. It is noted there that after the quadrupolar contributions $J_2, J_{2,2}$ (but not $J_{2,1}$) the next largest multipoles are $J_3, J_4, J_{3,1}$; all of the latter are similar in magnitude to each other and three orders of magnitude smaller than the quadrupolar terms but ...

1

The TIROS Technical Control Center (TTCC) performed the usual spacecraft control center functions: monitoring and control of its assigned spacecraft. Monitoring: TTCC was assigned the primary responsibility for processing telemetry data and evaluating attitude and spacecraft status.....Computer processing of telemetry data ...

1

The location is Masjid AL Haram in Makkah Saudi Arabia and The bright light is coming from one of the high beam light installed over Abraj al Bait(Makkah Clock Tower) From Wikipedia's Abraj Al Bait; Features: On special occasions such as new year, 16 bands of vertical lights shoot 10 km (6.2 mi) up into the sky.

Only top voted, non community-wiki answers of a minimum length are eligible