JUAN IN SPACE

Radiation and charged particles in space can be harmful to electronics, thus design mitigations should come into play. There are several sources of these elements in space, and we list out three of the most common sources. Sun Activity  Sun is basically a giant thermonuclear fusion reactor. Not only does it emit the Ultraviolet (UV) rays that you dread at noon, it also expels plasma at high velocity in  he name of solar wind. There are also these gigantic bursts erupting on the Sun's surface called solar flares. Sunspots serve as indicator for significant disturbances on the Sun. You can visit this link of you wish to see long-term historical record of solar activity from 1700. Galactic Cosmic Rays This is similar to the Sun's solar wind and activities, but coming from distant stars. Cosmic Rays are composed of many different elements such as Hydrogen, Helium and Carbon, and cover a very wide range of energies. They have sufficient energy to penetrate very ...

Satellites can also be endangered due to the presence of other satellites, space junks, and natural materials such as dust, comets or meteoroids. These floating objects can potentially collide, and with their high velocity movement, the impact will be severe.  Once a satellite is no longer functioning, it becomes a space debris or space junk. And right now, there may be hundreds of thousands pieces of space junks floating around. With these realization and challenge, responsible use of space is being actively promoted. Some satellites incorporate de-orbit mechanisms to prevent them from being an unwanted junk. Space Environment Vibration and Shock Gravity   Atmosphere Vacuum   Space junks Radiation and charged particles

Space is popular for its near-vacuum characteristic. However, along with this environment are potential issues with the satellite: Out-gassing From Earth's surface to space, pressure drops very significantly. This change of pressure can cause trapped gasses to be released, and these can re-condense to cause contamination or degradation of certain materials. While this is usually not a big issue, it can still affect delicate sensors and chips.  The concern on out-gassing is heightened when there are people involved, such as in the case of the ISS. A satellite bound for an ISS orbit stays in ISS for a certain duration (usually about a month). Since there are people living in the ISS, the released gasses can cause threat to their health. Cold Welding Moving parts in satellites such as deployment mechanisms entail challenges not only in the aspect of launch (vibrations and shock) but also in terms of successful operations (deployment). In vacuum, cold welding occurs...

Atmosphere affects satellites residing at the Low-Earth Orbit in the following ways: Drag Drag is a force that causes a satellite to fall back to Earth faster, shortening its lifetime. At less than 600 km from the Earth's surface, drag varies depending on how the atmosphere expands or contracts due to variations in solar activity. The impact of drag on the satellite also depends on the satellite's speed, size, shape and orientation. For instance, deployable panels can make the drag more prominent, leading to satellite's shorter lifetime. Atomic Oxygen Radiation and charged particles c an cause O 2 molecules to split apart in space, creating atomic oxygen, O. In this form, metal oxidation leading to corrosion or rusting becomes more intense. This can cause degradation of exposed areas and create issues with interconnects on solar arrays and on optical surfaces. Space Environment Vibration and Shock Gravity   Atmosphere Vacuum   Space junks R...

Contrary to what some people think, there is gravity in space only that it gets weaker with distance. Gravity is responsible for keeping the moon and other satellites orbit the Earth. However, it is also gravity that causes satellites, especially those near the Earth's surface to 'fall back' to Earth.  Slowly, as the satellite moves in space, it constantly gets pulled back to Earth. This event is aggravated by atmospheric drag, which is discussed in the next article. The closer a satellite is to the Earth's surface, expect that it will have a shorter lifetime. With this knowledge, you normally would want to bring your satellite to a higher altitude if you want it to stay in space for a longer time. Gravity can also help determine the amount of propellant that the spacecraft needs to move between orbits.  Space Environment Vibration and Shock Gravity  Atmosphere Vacuum   Space junks Radiation and charged particles References: NASA: What is Micr...

If you already tried riding an airplane, probably the most unforgettable moments of the ride would be the take-off and landing. During such times, you normally experience uncomfortable movements. It's not a perfect analogy, but basically, your satellite also experiences such uncomfortable movements during launch -- vibration and shock Vibration are relatively long-duration movements that occur during launch. There are several types of vibration that are attributed to various phenomena: Quasi-Static Acceleration attributed to: - Acceleration of the launch vehicle during launch - Low frequency vibrations due to staging effects Sinusoidal Vibration attributed to: - Structural response of the launch vehicle Random Vibration attributed to: - Aerodynamic events - Combustion phenomena Shock are short duration but high impact movements that occur due to the following: - Separation of fairing - Separation of other satellites on launcher - Separation of...

The 24th Session of the Asia-Pacific Regional Space Agency Forum (APRSAF-24) will be held in Bengaluru, India on November 14-17, 2017. This event is a good opportunity to meet space agencies, companies, universities and many other space-faring groups. You can learn a lot from attending this event, and even possibly find collaborators.  Last year, APRSAF was held in Manila, Philippines from November 15 to 18, 2016.  For more information on this event, you can visit their website .

The PHL-Microsat Program bagged the best paper award for their entry: Development of Deployable Antennas for Diwata-2 Microsatellite's Amateur Radio Payload during the COMNETSAT 2017 .  COMNETSAT is an IEEE sponsored International Conference on Communication, Networks and Satellite. The event is held annually and this year, it was held at Semarang, Indonesia. Image Courtesy of Ms. Salvatus Congratulations to the team!

We've mentioned in our previous article that Diwata-1 took an ISS orbit while Diwata-2 will be launched to a Sun-synchronous orbit. We've also mentioned that Agila-1 and Agila-2 were previously positioned to a certain degree of orbital slot.  But what are these things called orbit? Do I need to know these things? Why should I care? Orbit is the path followed by a satellite. You are probably aware that the moon orbits the Earth -- and moon is a natural satellite! There are several types of orbits, and each has their pros and cons. Let us take a look at some of the most common satellite orbits. Low Earth Orbit (LEO) Satellites in this orbit resides from 180 km to 3000 km from the Earth's surface. Due to its closeness to the surface, this orbit is easily accessible and launch opportunities are common, keeping the launch cost low. This orbit is popular for remote sensing applications since small and relatively less powerful cameras can work well from this dist...

Some satellites have an elliptical orbit. For these types of orbit, there are two commonly used terms: Apogee - This is the point at which the satellite is furthest from the Earth Perigee - This is the point at which the satellite is closest to the Earth   The terms apogee and perigee are specific to Earth. When the reference point is the Sun, these points are instead called aphelion and perihelion. The general term that describes these point is called apsis, and for any reference objects, the points are called apoapsis or apocenter and periapsis or pericenter. One important note is that the satellite travels more slowly at apogee than at any other point in orbit. Thus, when viewed from the Earth's surface, the satellite takes a long time to traverse the sky providing the user with a longer access or link time.

Just a year after acquiring Agila-1 , the Philippines acquired its second satellite, Agila-2. However, compared with Agila-1, Agila-2 is designed for a Philippine company and is not acquired while already in orbit. Agila-2 is a telecommunications satellite built by Space Systems/Loral (SS/L) for Mabuhay Satellite Corporation. It was launched to space from Xichang Satellite Launch Center via the Chang Zheng 3B rocket on August 19, 1997 (17:50 UTC) and was positioned at the 146°E longitude orbital slot. The mass varies from sources, but according to Gunter's Space, its launch mass is 3775 kg while its dry mass is 1800 kg (Wikipedia reports 2,820 kg launch mass). Agila-2 is claimed to be the most powerful telecommunications satellite in the entire Asia-Pacific region, and one of the most efficient in the industry. It carries 24 C-band, 24 Ku-band, and 6 extended C-band transponders, making it the satellite with the largest number of active transponders compared to any oth...

I am not sure how many of you is aware of this, but Diwata-1 is not the Philippines' first satellite. In 1996, Mabuhay Satellite Corporation under PLDT acquired Palapa B2-P, an Indonesian satellite that has been in space since March 20, 1987. From there, it was renamed to Agila-1 and became the Philippines' first satellite acquired while in orbit. Palapa B2-P was launched from Cape Canaveral aboard the Delta-3920 PAM-D rocket. It has a mass of 692 kg at the beginning of its life. It is a telecommunications satellite operating in the C-band - receiving from 5.925 GHz to 6.415 GHz and transmitting from 3.7 GHz to 4.2 GHz. Until the acquisition on 1996, it occupies the 113°E orbital slot. On August of the said year, it moved to its new orbital slot at 144°E. The Philippine's possession of the satellite was not long however, since it was deorbited 1998 - only more than a year after it was acquired. References: Gunter's Space Page: Palapa B1, B2, B2P, B2R, B4 ...

Everyone has their own mission in life, even a satellite. Well, harsh as it may sound but strictly speaking, a satellite exists only for the purpose of fulfilling its mission. And honestly, without a good mission, it is hard to get funding support for development and launch. Today, we will take a look at some common satellite mission categories. These categories also serve as satellite's classification by function which I mentioned in my previous post. Hopefully, this article will help us recognize the benefits of having a satellite. I mentioned before that space gives us opportunities to solve our problems, and these are some problems that satellite solve. I'm also actually paving the path for the sensitive topic of space economy and politics which I've been trying so hard to avoid, but well, we will get there. Haha. For now, here are your satellite missions. Communications Communication satellites dominate the space market. If you’ve watched NBA Live on your t...

There are many ways to classify satellites. These categories can be by function , by type of orbit or by mass. We will discuss satellite's functions and orbit in our next articles but for now, we will focus on satellite's classification by mass. Satellite's mass has direct impact on its cost, its development cycle and its launcher. The larger the satellite, the bigger is the development cost. This is because larger satellites carries more equipment such as redundancy modules, propellant, and more solar panels. Also, since it has more components and the lifetime and reliability expectation is higher, design reviews and tests conducted are also more than smaller satellites. Finally, larger satellites occupy larger space in the rocket, entailing higher launch cost. The names of the categories by mass is not an official convention. We can still, however use it for generic purposes: Large satellite - 1000 kg Medium-sized satellite - 500 kg to 1000 kg Small satellites...