Friday, February 24, 2017

Astronomers discovered 7 earth-sized planets orbiting nearby star

Astronomers have discovered seven earth-sized planets orbiting same star which is 40 light-years away according to a study published on wednesday ( 22nd Feb 2017) in the journal of nature.  The discovery was announced at a news conference at NASA headquarters in Washington.  

This discovery which is outside of our solar system is a rare event because the planets have the winning combination of being similar to the size of Earth and being all temperate, meaning they could have water on their surfaces and potentially support life..

The seven planets were all found in a tight formation around an ultra cool dwarf star called TRAPPIST-1.  Some estimates indicate that they are rocky planets rather than being gaseous like Jupiter.   Three planets are in habitable zone of the star and may even have oceans on their surfaces.  These three planets are called as Trappist-1e, 1f and 1g.

The researchers believe that Trappist-1f is the best candidate for supporting life. It is little bit cooler than Earth but can be suitable with the right atmosphere and enough green house gases.

These planets are very close to each other and the star.   They are all within five times within a space five times smaller than the distance from Mercury to our Sun.  This proximity allows the researchers to make a study of the planets in depth as well, gaining insight about planetary systems other than our own.  The seven planets of Trappist-1 are compared with Mercury, Venus, Earth and Mars.

As we move away from the closest to the star to outwards,  the planets have respective orbits from one and half to nearly 13 Earth days.  The orbit of the farthest planet is still not known.   If you stand on surface of one of the planets, you would receive 200 times less light than you get from the Sun, but you would still receive just as much energy to keep you warm since the star is so close..   It would also afford some views, as the other planets would appear in the sky as big as the moon. 

If you stand on Trappist-1f,  the star would appear three times as big as the sun in our sky.  The researchers believe that because of red nature of the star, the light would be a salmon hue.  The researchers believe that the planets were formed together further from the star.  Then they would have moved into their current lineup.   Like our moon,  the researchers believe that the planets closest to the star are tidally locked.  This means that the planets always face one side to the star.  One side of the planet is night and other side always day;.

As per preliminary studies on climate,  the researchers believe that the three planets which are closest to the star may be too warm to support liquid water, while the outermost planet, Trappist-1h, is probably too distant and cold to support water on the surface.

Trappist-1 is a star which is half the temperature and a tenth of the mass of the Sun.  It is red, dim and just a bit larger than Jupiter.  But these tiny ultra cool stars are common in our galaxy.  By using a global network ground-based telescopes like TRAPPIST and space-based telescopes like Spitzer, the researchers continued looking toward the Trappist system and were able to determine the  orbits and orbital periods and distances of the planets from the star, their radius and their masses.  

The researchers are planning to define the atmosphere of each planet as well as determine whether they truly do have liquid water on their surface and search for life on these planets.  All this would happen in the next decade.  Even though 40 light years is not too distant, but it would take us millions of years to reach this star system.  But for research purpose, it is a close opportunity and the best target to search for life beyond our solar system.

James Webb Space Telescope will be launched i 2018 and positioned at a distance of 1 million miles from Earth with a view of the Universe.  It can observe large exoplanets and detect starlight filtered through their atmosphere.. They are also searching for similar star systems to conduct atmosphere research.  Four telescopes named SPECULOOS ( Search for habitable planets EClipsing ULtra-cOOl Stars) based in Chile will survey the southern sky for this purpose.  

This star system will probably outlive us because this type of star evolves so slowly.  When out Sun dies, TRAPPIST-1 will still be young star and will live for another trillion years.   After we are all gone, if there is another part of the Universe for life to carry on,  it may be in the TRAPPIST-1 system.

Thursday, February 16, 2017

ISRO successfully launches 104 satellites with PSLV-C37

The Indian Space Research Organisation made  history once again by successfully launching PSLV-C37 Rocket with 104 satellites on-board there by creating a record of the most number of satellites in a single launch.   This is the world record now..   

This is yet another feather in the ISRO's cap, which has also launched the cheapest mission to MARS named Mangalyaan.  The PSLV-C37 which was launched from Satish Dhawan Space Center at Sriharikota carried aboard the CARTOSAT-2Series satellite as well as 103 nano-satellites from various countries.  

The PSLV-C37 took off at 09:20 AM IST ( 03:58 GMT ) on 15th FEbruary, 2017 and cruised at a speed of 27,000 Kms per hour ejecting all the 104 satellites into the orbit in 30 minutes time. The main payload of PSLV-C37 was 714 Kg satellite for earth observation and it was also loaded with 103 nano satellites weighing around 664 kilograms in total.  Three of the nano satellites are from India and the others are from countries including Israel, Kazakhstan, Netherlands, Switzerland, United Arab Emirates and 96 from USA.   Now India holds the record of launching the most number of satellites in one go, surpassing Russia which launched 39 satellites in a single mission in June, 2014.

The business of putting satellites into orbit for a fee is growing as phone, internet and other companies seek greater and more high-tech communications.  ISRO is competing with other international players for a greater share of the space market and is well known for its low-cost space programme.

The two solar arrays of Cartosat-2Series satellite were deployed automatically immediately after separation and the ISRO Telemetry, Tracking and Command Network at Bangalore took over the control of the satellite.  The satellite will be made operational to its final configuration very soon and it will provide remote sensing services using its panchromatic ( black and white ) and multispectral ( color ) cameras.  Out of the 103 satellites carried by PSLV-C37, two ISRO nano satellite-1 ( INS-1) weighing 8.4 Kg and INS-2 weighing 9.7 Kg are technology demonstration satellites from India.  The remaining satellites are from other countries - USA ( 96),  Netherlands ( 1), Switzerland ( 1), Israel (1), Kazakhistan (1) and UAE (1).   With today's launch, the total number of customer satellites launched by India has reached 180.

The list of satellites 104 is given below...

CartoSat-2D – ISRO, India (1)
CartoSat-2D is fifth in the series of CartoSat-2 remote-sensing satellites that capture and
send panchromatic and multispectral images of India from space. These images can be used
to monitor the coastal land use, urban and rural planning, road networks and water distribution
, and to identify natural and man-made features. Weighing 714 kilograms, ISRO’s CartoSat-2D
 is the heaviest satellite onboard the PSLV-C37 and accounts for more than half the 1,377
kilogram payload of the rocket.
INS-1A – ISRO, India (1)
ISRO Nano Satellite-1A is an 8.4-kilogram research satellite that will stay operational for six
months, and carry two science payloads. One is the Surface BRDF Radiometer (SBR) payload
that can be used measure the Bidirectional Reflectance Distribution Function (BRDF) of targets
on the Earth's surface and will be able to take readings of the sunlight reflected off different
surface features. The other is the Single Event Upset Monitor (SEUM), which can be used to
track Single Event Upsets that happen due to high energy radiation in space environment in
Commercial, Off-the-Shelf (COTS) electronic components.
INS-1B – ISRO, India (1)
ISRO Nano Satellite-1B aboard the new PSLV-C37 rocket is also a modular satellite similar to
the INS-1B, but weighs 9.7 kilogram. It is expected to remain operational for 6-12 months and
 also carries two science payloads: the Earth Exosphere Lyman Alpha Analyser (EELA) and
 Origami Camera payload from ISRO's Space Application Centre (SAC). EELA keeps track of
 terrestrial exospheric line-of-sight neutral atomic hydrogen Lyman Alpha flux and can give an
 estimate for the interplanetary hydrogen Lyman Alpha background flux by means of deep
space observations. The Origami Camera, on the other hand, is a remote sensing colour
camera that can take high-resolution pictures of the Earth with a small package.
Flock-3p – Plant Labs, United States of America (88)
ISRO’s PSLV-C37 will take Planet Labs’ 88 Flock-3p nano-satellites to space, bringing the total
number of Dove satellites in space to 100. The satellites will be able to capture images of the
entire Earth surface once a day and take pictures in line-scanner formation at mid-morning
 pass times to minimise shadows in the images they capture.
Lemur-2 – Spire Global, United States of America (8)
Eight Lemur-2 nano-satellites operated by Spire Global of the USA, each of which carries a
 meteorological payload that can determine the atmospheric pressure, humidity and temp-
erature using signals from GPS satellites in Earth’s atmosphere. These nano-satellites also
 carry a payload that allows them to monitor and send forward tracking data from seafaring
Al-Farabi-1 – Al-Farabi Kazakh National University, Kazakhstan (1)
The Al-Farabi-1 is a nano-satellite developed by students of the Kazakhstan’s Al-Farabi
Kazakh National University. It weighs 1.7 kilograms and will work on calculating uplink /
downlink and ADCS Mission algorithms and testing of self-made components.
BGUSat – Ben Gurion University, Israel (1)
A 3U CubeSat nano-satellite developed by Israel’s Ben Gurion University, BGUSat carries
 two imaging payloads, an experimental GPS receiver and an optical communication expe-
riment. It measures 10x10x30 centimetres and weighs 5 kilograms. The BGUSat’s cameras
can track climate phenomena and its guidance system enables the operators choose the
 areas to shoot and research through a dedicated ground station at BGU. 
Nayif-1 – Emirates Institution for Advanced Science and Technology (EIAST), UAE (1)
Students at UAE’s Emirates Institution for Advanced Science and Technology (EIAST) deve-
loped the Nayif-1 nano-satellite and will be used for educational purposes.
DIDO-2 – SpacePharma, Israel and Switzerland (1)
DIDO-2 is a microgravity research nano-satellite that can be used to conduct biochemical
and physical experiments in micro-gravity. It will serve pharmaceutical companies, as well as
 other organisations, and will be able to send back data to Earth-based researchers via the
 on-board microscope.
PEASS – PEASS Consortium, Netherlands, Germany, Belgium, and Israel (1)
PiezoElectric Assisted Smart Satellite Structure or PEASS is a nano-satellite that can be
 used to evaluate and qualify ‘smart structures’ which combine composite panels, piezo-
electric materials, and next-generation sensors.
The launch video is shown below..

Here is a video of the onboard camera where we can see all the events till seperation of all the satellites.

Saturday, December 10, 2016

Indian Resource mapping satellite RESOURCESAT-2A blasted off from Sriharikota by PSLV-C36 Rocket

Once again India's PSLV delivered to orbit on Wednesday ( 7th December, 2016) the country's third space mission dedicated to mapping of natural resources creating a record year for Indian launch hitory.  

The Resurcesat-2A was launched by India's PSLV rocket ( PSLV-C36) in its 38th flight successfully at 10:25 hrs IST on 7th December, 2016.  The satellite weighed 1235 Kg.  

The 36 hur count down began on monday and the ground crew filled the PSLV's second and fourth stages with liquid fuels.   The PSLV-C36 lifted off at 04:55 GMT and climbed through a heavy rain shower and low clouds from the First Launch Pad of Satish Dhawan Space Center with 1.7 million pounds of thrust. 

The first four of the 12 meter auxiliary motors ( strap-on motors ) burned out and jettisoned around 70 seconds after lift-off followed by release of the last pair of boosters at T+92 seconds.   The first stage of the rocket consumed the solid propellant by T+1 minute and 50 seconds giving way to the Rocket's hydrazine-burning second stage Vikas Engine around 74 kilometers above Earth for a firing which lasted about 2 and 1/2 minutes with 1,80,000 pounds of thrust.   The onboard computers began closed-loop guidance during the second stage burn and the rocket's 3.2 meter diameter payload fairing fell down from the rocket at T+150 seconds.  

The PSLV headed eastwards first and then turned south in a "dogleg" maneuver to avoid flying over Sri Lanka accelerating to orbital velocity over Indian Ocean.   Once the Vikas Engine ( second stage ) emptied its 42 metric tonne supply of hydrazine and nitrogen tetroxide propellants, the third stage ignited around T+4 minutes 23 seconds for nearly two minutes and then coasted off until separating from the Rocket's fourth stage at around T+ 8 minutes 41 seconds.  

The twin engine liquid fueled fourth stage took control  of the mission at T+ 8 minutes 51 seconds for an eight minute firing to obtain proper velocity to enter the targeted polar orbit.  Resourcesat-2A was separated at around 18 minutes after lift-off.  

The Resourcesat-2A will track agriculture, water resources, soil contamination and the growth of Indian cities.  This is a follow up for Resourcesat 1 and Resourcesat 2 launched earlier in 2003 and 2011.  The spacecraft was put into an orbit of 823 Kms high at an inclination of 98.7 degrees to equator.

The PSLV-C36 launched on wednesday demonstrated several upgrades to the PSLV's avionics systems including the improved navigation system, a fiber-optic gyroscope, indigenously-produced computer processors and an automated fueling system to the fourth stage.  The streamlined automatic fuelling system saved one day in the launch preparations and also for a safe work environment for ground engineers to prepare the rocket.

Here is a video of PSLV-C36 Launch  ....

India's PSLV-C35 successfully places eight satellites into two different orbit in a single flight

Again Indian Space Research Organization has made history by placing eight satellites into two different orbits in a single mission using PSLV-C35 Rocket.  In its 37th flight ( PSLV-C35) india's Polar Satellite Launch Vehicle has successfully launched the 371 Kg SCATSAT-1 along with seven co-passenger satllites on 26th September, 2016 from its space port Satish Dhawan Space Center, Sriharikota  

This is the 36th consecutive successful flight of PSLV.  The total weight of the satellites is 675 Kg.  This is the first mission of PSLV to launch satellites into two different orbits and also this is the longest mission of PSLV till date and completed in 2 hours 15 minutes and 33 seconds after lift off.  

The PSLV-C35 lifted off at 09:12 hrs IST from the First Launch Pad of Satish Dhawan Space Center located at Sriharikota, Andhra Pradesh.  All the events like strap-on ignitions and separations, first stage separation, second stage ignition and separation, third stage ignition and separation, payload fairing separation, fourth stage ignition and cut-off took place as planned.  After 16 minutes and 56 seconds, the vehicle achieved a polar sun synchronous orbit of 724 Km with an inclination at an angle of 98.1 degrees to the equator and 37 seconds later the primary satellite SCATSAT-1 got separated.  

The two solar panels were deployed after separation of SCATSAT-1 and ISTRAC at Bangalore took the control of the satellite.  The satellite would provide weather related information using scatterometer payload.  The data would be useful in weather forecasting services as well as cyclone detection and tracking.  The PSLV mission continued after separation of SCATSAT-1 carrying the other 7 satellites.  The 4th stage coasted over the south pole and started ascending towards northern hemisphere.  After 1 hour 22 minutes 38 seconds after lift-off as the fourth stage was in North Pole region, the two engines of fourth stage were reignited and fired for 20 seconds.  Due to this firing, the rocket entered into an elliptical orbit of 725 Km  x  670 Km.   

The PSLV once again was coasting near south pole after 50 minutes, the engines were fired once again for 20 seconds.  This second firing made the fourth stage to enter into a circular orbit of 669 Km height inclined at 98.2 degrees to the equator.  After 37 seconds, the dual launch adopter was successfully separated from PSLV-C35 fourth stage.  30 seconds later, ALSat1N satellite got separated.  Following this, the NLS-19, PRATHAM, PISAT, ALSAT-1B, and Path finder-1 were separated in a pre determined sequence.

PRATHAm weighing 10 Kg and PISAT weighing 5.25 Kg  were made by Indian universities and academic institutions with the involvement of students of IIT Mumbai and PES University, Bangalore.   

Here is a video of PSLV-C35 Launch.....

Sunday, September 11, 2016

GSLV-F05 places India's Advanced Weather Satellite INSAT-3DR into orbit on 8th September, 2016

The Indian Space Research Organisation ( ISRO ) on thursday, 8th September, 2016 successfully placed its advanced weather satellite INSAT-3DR using the GSLV-F05 Launch Vehicle.

This is the maiden operational flight of the heavy-duty Rocket GSLV-F05 of India fitted with indigenous cryogenic upper stage.  The advanced weather satellite INSAT-3DR was successfully placed into the intended orbit by GSLV-F05 on thursday, 8th September, 2016 at exactly 16:50 hrs IST from the space port of India, Sriharikota.

The 49 meter GSLV-F05 lifted off from the second launch pad at Satish Dhawan Space Center, Sriharikota at 4:50 PM and injected the 2,211 Kg INSAT-3DR satellite into a Geosynchronous Transfer Orbit about 17 minutes later.  It was origninally scheduled to lift off at 4:10 PM IST but due to a delay in Cryo stage filling operations, it was rescheduled to 4:50 PM.

The INSAT-3DR has a mission life of 10 years and will provide service continuity to earlier meterological satellites and further augment the capability to provide various meteorological, search and rescue services.    This is the 10th GSLV flight and assumes significance because this is the first operational flight of GSLV fitted with Indian Cryo stage.  Earlier GSLV launches were under developmental phase.  GSLV-F05 marked a hat-trick of success for the indigenously developed Cryo stage after GSLV-D5 ( January, 2014) and GSLV-D6 ( August, 2015 ) missions which launched GSAT-14 and GSAT-6 satellites into space.

The orbit raising operations from Master Control Facility at Hasan were also successful.  INSAT-3DR would supplement the services of INSAT-3D launched from French Guiana on 26th July, 2013.  The payloads of this satellite are Imager, Sounder, Data-Relay Transponder and Satellite aided search and rescue transponder.  The images would generate the images of Earth every 26 minutes and provide information about various parameters, sea surface temperature, snow cover, cloud motion winds.  The sounder would provide informatio about temperature and humidity.  The data relay transponder will be used for receiving meteorological, hydrological and coeanographic data.  The satellite aided search and rescue transponder would pick up and relay alert signals originating from distress beacon of maritime, aviation, among others.

Here is a video of the live launch.....

India successfully tests its ScramJet Engine technology - ATV D02

An ATV rocket, fitted with two scramjet engines, lifts off from the Satish Dhawan Space Centre (SDSC) in Sriharikota on Aug. 28, 2016.In an attempt to make the rockets lighter and carry heavier payloads, ISRO has planned to flight test the air-breathing rocket which will use atmospheric oxygen as fuel.  Air breathing engines use atmospheric oxygen and burn it with the stored on-board fuel to generate the upward thrust.  Conventional rockets carry both oxygen and fuel on board.

ISRO on 28th August, 2016 has successfully tested a pair of its scramjet engines - an air breathing ramjet in which combustion takes in a super sonic air flow.  The engines were tested during a sub-orbital flight of Advanced Technology Vehicle ( ATV D02).

The total weight of the ATV rocket was 3270 Kgs and is based on Rohini-560 lifted off from Satish Dhawan Space Center, Sriharikota at 06:00 AM IST on 28th August, 2016.  The total flight duration lasted about 5 minutes is the India's first experimental mission of the scramjet engine technology to develop indigenous air-breathing propulsion system..

During the flight, ISRO has tested the scramjet engines for five seconds.  Once the second stage reached the desired conditions for start-up of the engine, the scramjet engines ignited and worked for about 5 seconds.  The total mission of ATV-D02 ended with a planned touch down of the rocket in Bay of Bengal at about 320 Kilometers from Sriharikota.  All the tests were conducted successfully as per ISRO statement.

The scramjet engines which use atmospheric oxygen can cut the costs of rocket launches by reducing the amount of oxidizer needed to be carried along with the fuel.  With this flight,  India became the fourth country in the world to flight test a scramjet engine.  This launch marks an important mile stone in Indian space programme.

The mission which was earlier scheduled in July, 2016 was delayed due to the disappearance of Indian Air Force AN 32 plane on July 22, 2016 as many ships and aircrafts were patrolling the sea looking for the missing plane and people.

Here is a video about ATV-D02 Mission.

Saturday, July 23, 2016

What is the speed at which Earth is moving?

We all feel that we are standing still on Earth.  We do not feel any movement in our surrounding areas.  But if we see at the sky, we can find evidence that we are moving.  

Some of the earliest astronomers proposed that Earth is at the center of everything and Sun rotated around us which caused sun rise and sun set - the same for movement of moon as well as planets.  This theory is not correct because some times a planet would back up in the sky before resuming its forward direction.. We know that this motion called retrograde motion - happens when Earth is "catching up" with another planet in its orbit.  If we take example Mars orbits farther from sun than Earth.  At one point in respective orbits of Earth and Mars, we catch up to the Mars and pass it by.  As we pass it by, the planet moves backwards in the sky.  Then it moves forward again as we have passed.

We know that it takes 365 days for Earth to orbit around Sun.  If we look at a close-up star in summer and look at it again in winter,  its position in the sky changes because we are at a different point in the orbit.  We see the star from different vantage points.  With simple calculations, using parallax, we can figure out the distance to the star.  Now let us see how fast are we moving..

How fast is the Earth spinning?

The spin of Earth is constant  but the actual speed depends on what latitude you are located. The circumference of Earth is roughly 40,070 kilometers ( around the equator ).  if we estimate that a day is 24 hours long,  we get a speed of Earth at Equator as 1.670 Kms per hour.   This is the fastest speed because we will not be moving at this speed at other latitudes.

If we move half way up the globe to 45 degrees in latitude ( either north or south ), we can calculate the speed by using the cosine of the latitude.  The cosine of 45 degrees is 0.707, the spin speed at 45 degrees latitude is roughly 0.707 X 1.67 = 1.18 Kms per hour.  This speed decreases as we move either towards north or south poles.  When you reach north or south poles, the speed is very very slow.  -  It takes entire day to spin in place.

The space agencies try to take advantage of the Earth's spin.  If they want to send humans to International Space Station, the preferred location to do so is close to Equator.  This is the reason space shuttles are launched from Florida.  By doing so and launching in the same direction of Earth's spin, the rockets get a speed boost to help them fly into space.  Now let us see how fast are we orbiting the Sun?

How fast is the Earth spinning?

The spin of the Earth is not only the motion we have in space.  The Earth also rotates around sun at a speed of about 1,07,000 Kms per hour.  We can calculate this also with the help of mathematics.

The earth takes about 365 days to orbit the Sun and the orbit is an Ellipse. To make the maths simpler,  let us assume that it is a circle..So the orbit of Earth is the circumference of a circle.  The distance of Earth from sun is  14,95,97,870 Kilometers, this is called as Angstrom Unit.   The circumference of Earth is equal to  2 x π x r,  so in one year, Earth travels about 940 million kilometers.  We know that the speed is equal to distance travelled by the time taken,  Earth's speed in our orbit around Sun is calculated by dividing 940 million kilometers by 365.25 days and dividing that results by 24 gives us the speed in Kilometers per hour...  Earth travels about 2.6 million kilometers in a day or 1,07,226 Kms per hour ( 29.785 Kms per second)..

The Sun and Galaxies also move.....

Do you know that the Sun has an orbit of its own in the Milky Way Galaxy.  The Sun is about 25,000 light years from the center of Milky Way Galaxy.  and the Milky Way is thought to be about 1,00,000 light years across.  We are thought to be about half way out from the center according to Stanford University.  The sun and solar system appear to be moving at 200 Kms per second or an average speed of 8,28,000 Kms per hour.  Even at this rapid speed, the solar system takes about 230 million years to travel all the way around Milky Way Galaxy.

Our Galaxy also moves in space relative to other galaxies.  In 4 billion years, our galaxy would collide with its nearest neighbour, the Andromeda Galaxy.  The two are rushing towards each other at about 112 Kms per second.   So everything in the universe is in motion.

What happ ens if Earth stops rotating.....

what would happen if the process was more gradual?  This is a more likely scenario over billions of years because Sun and Moon are tugging on Earth's spin.  This would give plenty of time for the humans, animals and trees to get used to the change. By laws of physics, the slowest spinning speed of Earth would be one revolution every 365 days..This situation is called as "Sun Synchronous" and would force one side of our planet to always face the Sun and other side to permanently face away.  Our moon is already in Earth-synchronous rotation where one side of moon is always facing us.

There would be other effects if the Earth completely stopped spinning.  As per NASA, the magnetic field would disappear because it is thought to be generated due to spin. We would lose out colourful auroras, and the Van Allen radiation belts surrounding our planet would probably disappear too.  Then Earth would be naked against the fury of the Sun.  Every time the Sun sends a coronal mass ejection towards Earth, it would hit the surface and bathe everything in the radiation.

Another effect : most spots on Earth would have day light for half a year and nights for other half.  The surface temperature during the day would change depending on the latitude you are in.  The Equator would be hotter than it is now because the Sun rays directly fall on it.  There will not be sun rise and sun set at poles.  The sun simply would just move up and down in the sky during the year according to the orbit and tilt.  .This long term temperature gradient would change the atmosphere wind circulation pattern.  The air would move from equator to the poles rather than in wind systems parallel to equator like they are now.