the purpose may be used for positioning, eg, during rendezvous docking. The ascent module has to dock with orbiter very precisely, on the scale of centimeter, or millimeter.
>>> RF ranging. Minmum 2 antenna rods needed for ranging. 3 rods can make 3 measurements same time, to increase accuracy.
Upon successful capture of ascent module, the moon samples can then be transferred to re-entry capsule ( located inside the orbiter)
or it is a periscope( backup periscope bck-4), as in soyuz spacecraft ?
is it RF metrology antenna or FFRF (formation flying Radio Frequency) sensor in PRISMA
from France , Swedish Space Corp or CNES? the main purpose is for automatic rendezvous of two spacecrafts
If it is really a FFRF for rendezvous, why are they mounted on one side of spacecraft, rather than the "mating" side?
a high-gain antenna is particularly good at transmitting signals in a narrow beam whereas a low-gain antenna tends to send its signal in a much wider sweep of directions.
Because a low-gain antenna spreads its power out over a wider volume in space, the signal received by a ground station is weaker. This signal cannot carry as much information as a high-gain signal where the available power is concentrated to beam the signal accurately back to its target. Dish-shaped antennas are particularly good at focusing radio beams and so make excellent high-gain antennas.
Spacecraft always carry both high- and low-gain antennas. Although the high-gain antenna is used to return the majority of the data collected, if the spacecraft has to turn even a little, the high-gain signal could miss the Earth. The low-gain antenna does not suffer from such a problem because it transmits over a wider volume.
So even though they transmit and receive at slower rates, low-gain antennas are used to take over as back-ups when the high-gain antenna cannot be used. Spacecraft normally carry two of them on opposite sides. That way, they provide total coverage around the spacecraft.
Low-gain antennas are essential in critical situations. For example, if a spacecraft lost the ability to point itself, the low-gain antenna will always receive signals from Earth, allowing engineers to begin fixing the problem.
Question: adding 1/4 teaspoon of 10% phosphoric acid to 19 litres of water, what will be the pH? Let's go through the calculations step by step. Step 1. Convert mass ( or volume) of 10% phosphoric acid to mole per litre ( mol/L) The above calculation shows that 1/4 tsp of H3PO4 acid is 6.97e-5 mol/L Step 2. Input this value to BATE (or other app) to calculate pH The answer: pH = 4.16, ie too acidic !? If you use pipette instead of teaspoon, 1 drop = 0.05ml. So 1/4 TSP means roughly 25 drops If you actually aim for pH 5.6 (which is optimum pH for mashing), conc will be 2.51 e-6, or 1/100 tsp , 0.044 ml, roughly 1 drop Let's roll back a bit. From recipes of BarleyWine , summer rye , hefe Gordon Strong suggested to use 1/4 teaspoon of 10% phosphoric acid, which is targeting pH of 5.5..... Discussion on homebrewtalk forum. However using online BF water calc , Sparge pH would be 4.6. but he also added 1 tsp of CaCl2. 2H20. Mash pH change from 5.7 t...
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