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Moment of truth approaches for India’s Mars Orbiter Mission

November 28, 2013

When everything is for the first time,achievements are incremental and there are very many critical “moments of truth” to meet and overcome. But now comes a very large “moment of truth” as ISRO prepares to inject the Mars Orbiter spacecraft into its Trans Mars Trajectory.

India’s Mars Orbiter (Mangalyaan) is currently in its final orbit around the earth and is scheduled to fire its 440 Newton liquid engine at 0049 hours IST on Sunday morning ( 1919 GMT Saturday 30th November).  It entered its final Earth orbit yesterday which has an orbital period of 5575 minutes (just under 4 days) and it should be approaching apogee later tonight (early hours of Friday morning) and the next engine burn will take place at perigee. Currently apogee is about 193,000 km from earth and perigee is around 350km.

The spacecraft must first be manoeuvred into the right attitude using its thrusters for the firing of its main engine which must then be fired to impart the correct change of velocity (delta-vee). Both, an incorrect attitude and/or an incorrect delta-vee are potential sources of error. Three mid-course corrections are planned  (the first on December 11th) but the margin of error allowable is still extremely small. Too low a velocity change could leave the craft in earth orbit or put it into a heliocentric orbit which does not get close enough to Mars. Too high a delta-vee would also put the craft into a heliocentric orbit which would eventually decay into the sun. I believe there is no chance of achieving a velocity high enough to escape the sun. And even if the velocity change is correct but the direction is too far in error then just another orbital path around the sun would result.

NDTV:“The trans-Mars injection- we are planning to depart on December 1, 2013 early hours of 00:49 hours IST and we are going to burn a liquid engine for duration of roughly 23 minutes which will impart an incremental velocity of 648 metres per second consuming a fuel of 198 kgs,” ISRO Scientific Secretary V Koteswara Rao told reporters in Bangalore.

K. Radhakrishnan, ISRO Chairman. (For the) trans-Mars injection and its insertion into the Martian orbit, the firing of the liquid engine is done in a closed loop mode. Here, a precision accelerometer is used to estimate the incremental velocity added as the liquid engine burns and when the accelerometer gives a feedback that the required incremental velocity added to the spacecraft has been achieved, the burning of the liquid engine is automatically terminated. So, minor variations in the performance of the liquid engine will not matter because we are cutting off its burning based on the delta-v that is achieved. That is why we call it closed loop of firing. … The spacecraft’s propulsion system, i.e., the 440 Newton liquid engine, will complete its first phase of operations on December 1. It has to be re-started for its operation on September 24 (2014).

MOM Trans Mars Injection ISRO

MOM Trans Mars Injection ISRO

ISRO: This voyage is achieved by a combination of navigation and propulsion technologies, governed by the gravity of Sun and Mars, and assisted by the 440 N Liquid engine. Further fine tuning of the trajectory is achieved using the Attitude and Orbit Control Thrusters during the Trajectory Correction maneuvers planned en route.

… on December 11, we plan to have one small firing for mid-course correction of the spacecraft. There may be one more mid-course correction during the helio-centric phase, and subsequently, a fortnight before the spacecraft’s arrival near Mars, there will be one more mid-course correction. So there will be three mid-course corrections between December 1, 2013 and September 24, 2014. 

Mangalyaan is eventually to be placed into a Martian orbit, with a periapsis height of 365 km, apoapsis height of 80,000 km and an orbital period of about 77 hours.

So on Saturday I shall have as many of my fingers crossed as I can manage. I suspect there will be many others doing the same across India.

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Political statues in India cost more than the Mars Orbiter Mission

November 24, 2013

A very critical moment for the Indian Mars Orbiter Mission (“Mangalyaan“) comes a week from today when the spacecraft’s engine has to be fired as it reaches perigee in its Earth orbit, to insert  it into  a trajectory to reach Mars some 10 months later.

The Mission has been criticised both in the West and in India (here and here for example) as being too expensive, too elitist and the wrong priority for a developing country like India. I think such criticism misses the point. “The Indian Mars Orbiter Mission is primarily a test of technology and capability and self-confidence and self-belief”. The cost pales in comparison with the spend on religious festivities and what other much less productive projects can cost. As an example of what frugal engineering can achieve, the inspiration and ingenuity it can foster is immeasurable.

Manoj KumarPatairiya writes in the New York Times:

If the Mars Orbiter successfully reaches the vicinity of the planet in September 2014, after 300 days’ journey into deep space, it will make India the first Asian country and the fourth in the world to reach the red planet. …. The mission has, however, started an intense debate. While its supporters trumpet its incredibly low cost of around $75 million (a fraction of the cost of a similar American expedition), critics question the logic behind spending any amount when India is dealing with such deep-rooted problems as widespread hunger, poverty and corruption. ……. 

But U. R. Rao, a former chairman of the Indian Space Research Organization, compared the $75 million spent on the mission to the amount Indians spend on Diwali crackers for one day: “For going all the way to Mars, just one-tenth of the money is being spent. So, why are they shouting?”

Part of the reason the mission is so much less expensive is that it is able to take advantage of existing deep space communications systems and navigation support from NASA. But India is becoming known for its low-cost innovations in many diverse fields, including health care, renewable energy, sanitation, mobile technology and tablet computers. Indian scientists like to share this anecdote: “Americans spent millions to develop a pen that will not leak in space, whereas Russians used a pencil!”

The cost of the Indian Mars mission is about $75 million and just to put it into perspective:

  • Mayawati’s park in Noida was constructed at the cost of $130 million, and has 24 huge statues of elephants, and one of herself.
  • the total cost to build the Narendra Modi sponsored “Statue of Unity” is estimated to be about $340 million

Politicians will of course argue that the “feel-good” effects generated by such monuments to themselves or their heroes are well worth the cost!

If the MOM succeeds in its main objectives, there is even a case for using the window that is coming in 2018 to attempt a manned trip around Mars and back in 501 days.

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MOM turns its camera on Earth while preparing for critical insertion into Mars trajectory

November 21, 2013

While the MOM spacecraft “Mangalyaan” is in orbit around Earth, its systems and scientific instruments are being tested to prepare for the critical burn at 0036 IST on 1st December (1906 GMT 30th November) to inject it into a Mars trajectory. The colour camera has been turned on Earth during testing and ISRO has released this photograph.

This image was taken yesterday at around 1350 hrs (IST) from a height of almost 70,000 km above earth and has a spatial resolution of 3.5 km.

Earth from MOM 20131120 image ISRO

Earth from MOM 20131120 image ISRO

The spacecraft’s engine has so far been fired as follows:

  • first orbit-raising manoeuvre 416 seconds
  • second orbit raising manoeuvre 570.6 seconds
  • third orbit raising manoeuvre 707 seconds
  • fourth orbit-raising manoeuvre (time not specified, firing curtailed inadvertently)
  • fourth supplementary orbit raising manoeuvre 303.8 seconds
  • fifth orbit raising manoeuvre 243.5 seconds

The next critical burn (the seventh) has to to use the 440 Newton liquid engine again to impart a delta-v of nearly 648 m/s and the engine will have its longest burn time of 1,351 seconds. Three mid course corrections on the spacecraft’s journey to Mars are planned for and the fuel carried has to also cater for finally braking to enter into Mars orbit.

The Hindu carries a long, fascinating interview with  K. Radhakrishnan, ISRO Chairman. The article is a little unusual in its length and technical detail which most Indian newspapers would fight shy of! Some selected extracts below but the entire interview is worth reading:

After the Polar Satellite Launch Vehicle (PSLV-C25) put India’s Mars Orbiter into a perfect earth-bound orbit on November 5, it has been a smooth journey so far for the spacecraft. The Indian Space Research Organisation (ISRO) boosted the Mars Orbiter’s apogee in six complex manoeuvres executed between November 7 and 16. ISRO did this by giving commands from the ground to the spacecraft’s propulsion system, called 440 Newton engine, to fire. A crucial event of the trans-Mars injection of the spacecraft will take place on December 1 by a prolonged firing of the 440 Newton engine.

…. Till now, we have completed six manoeuvres including a supplementary one. Currently, the spacecraft’s apogee is 1,92,915 km. 

In the early hours of December 1, around 00.36 hours, we have the trans-Mars injection of our Mars spacecraft. On that day, we are going to use the 440 Newton liquid engine again to impart a delta-v, that is, an incremental velocity of nearly 648 metres a second to the spacecraft and the engine will burn for 1,351 seconds. It is crucial in the sense that we need to give the exact velocity required to take the spacecraft from the earth-orbit, passing through the sphere of influence of the earth which extends up to 9.25 lakh km from the earth, cruise through the long helio-centric phase, then get into the sphere of influence of Mars, and on its arrival near Mars on September 24, 2014, it has to be put into 376 km plus or minus 50 km above Mars at that point of time. On the same day, the next crucial operation of the spacecraft’s Mars orbit insertion has to take place. When this running of the 440 Newton liquid engine takes place on December 1, we also have eight numbers of 22 Newton control thrusters firing. 

There are two tasks for them. One is the spacecraft’s attitude control. Secondly, if it is required, they will aid the 440 Newton thrusters to augment its thrust-level. Both the functions will be performed and the Mars spacecraft will then be moving towards the helio-centric orbit. Then on December 11, we plan to have one small firing for mid-course correction of the spacecraft. There may be one more mid-course correction during the helio-centric phase, and subsequently, a fortnight before the spacecraft’s arrival near Mars, there will be one more mid-course correction. So there will be three mid-course corrections between December 1, 2013 and September 24, 2014. 

With the velocity imparted to the spacecraft on December 1, 2013, we will have an estimate of its expected position on September 24, 2014. We will be continuously tracking the spacecraft and if there are deviations vis-à-vis the end goal, we will make the corrections. So December 1 will be a crucial operation. The spacecraft’s propulsion system, i.e., the 440 Newton liquid engine, will complete its first phase of operations on December 1. It has to be re-started for its operation on September 24. There is thus a long gap. 

How confident are you that you can re-start the 440 Newton engine after it has hibernated in deep space for about 300 days during the spacecraft’s voyage? 

We have been using the 440 Newton engine for our Geo-synchronous Satellite – GSAT- missions where the spacecraft’s orbit has to be raised about a week after its launch. In the case of Chandrayaan-1, we had to restart the operation after a fortnight. For that, we had qualified the liquid engine in 2008 to restart after one month. 

During the last two years, considering the specific requirements of our Mars Orbiter Mission for re-starting the spacecraft’s 440 Newton engine after it has idled for about 300 days, we had done these two actions. One is we have provided a set of parallel circuits for the propellants’ flow-lines and also provided redundancy in the form of a latch-valve. So what essentially happens is that one portion of the fluid circuit will be closed after December 1. The parallel path will be energised for the operation in September 2014. 

……. In the spacecraft’s orbit-raising manoeuvres, during its trans-Mars injection and its insertion into the Martian orbit, the firing of the liquid engine is done in a closed loop mode. Here, a precision accelerometer is used to estimate the incremental velocity added as the liquid engine burns and when the accelerometer gives a feedback that the required incremental velocity added to the spacecraft has been achieved, the burning of the liquid engine is automatically terminated. So, minor variations in the performance of the liquid engine will not matter because we are cutting off its burning based on the delta-v that is achieved. That is why we call it closed loop of firing. …… 

Up to (925,000) km from the Earth, the spacecraft will be in the sphere of influence of the Earth. Subsequently, it will be moving into the helio-centric phase of its flight. It is a long one, where you have to look at the influence of other planets and the Moon and then the solar radiation pressure acting on the spacecraft. That pressure varies with respect to time because the geometry of the sun and the spacecraft matters here. This is something we have not done so far and this helio-centric phase of the flight is new to us. 

In Chandrayaan-1, we had travelled up to (400,000) km, which was well within the sphere of influence of the Earth. But here for the first time, we are moving out of the sphere of influence of the earth. So how the spacecraft will behave during the helio-centric flight of 680 million km along the arc is new to us. Then the spacecraft gets into the sphere of influence of Mars which is nearly six lakh km from Mars. 

From our understanding of the Mars gravity model, the influence of the atmosphere of Mars, the influence of the two satellites of Mars and the solar radiation pressure there on the spacecraft are very important. This is also a new thing that we are attempting. 

So the navigation of the Mars spacecraft from the orbit of the Earth to the orbit of Mars, passing through all these three phases, is a new knowledge that we are acquiring and validating during the next 300 and odd days.

Read the whole article.

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Smooth MAVEN launch followed by flawless insertion into Mars trajectory

November 18, 2013

A very smooth launch by NASA and lift-off exactly as planned.

And with the power of the Atlas V, just 52 minutes 42 seconds after launch MAVEN had separated from the launch vehicle and had been inserted into a Hohmann Transfer Orbit and on trajectory to reach Mars on 22nd September 2014.

NASA:

At 1:28 p.m. EST, NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft began its 10-month journey to Mars orbit, launching aboard a United Launch Alliance Atlas V rocket from Cape Canaveral Air Force Station in Florida. MAVEN will take critical measurements of the Martian upper atmosphere to help scientists understand climate change over the Red Planet’s history.

The Centaur’s single RL-10A-4-2 engine ended its second burn on time. The next major milestone is the release of NASA’s MAVEN spacecraft.

Separation! Maven is now on its own.

Very smooth and absolutely flawless.

In the meantime the Indian Mars Orbiter Mission’s Mangalyaan has another 13 days in Earth orbit in its current orbit (193,000 km apogee) before one more burn of its motors puts it also into a Hohmann Transfer Orbit which should get it to Mars orbit on 24th September 2014. Spacecraft systems – most being operated for the first (or second) time – will be tested while in earth orbit.

The “poor man’s route” to Mars!

And India and ISRO have some 49 years of US NASA Mars missions to catch up to.

And while NASA is showing live feed of the launch, ISRO’s web-site is down – presumably because it could not handle the traffic. The FB page seems fine.

isro down 20131118

isro down 20131118

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Alternate paths to Mars: NASA’s MAVEN compared to India’s MOM

November 16, 2013

Update! 18th November 2013. The launch of MAVEN – in about 1 hour from now – can be seen live on NASA TV.

The Indian Mars Orbiter Mission is primarily a test of technology and capability and self-confidence and self-belief.

With a very limited budget.

The scientific investigations of the planet and the Martian atmosphere are only a secondary or even a tertiary objective. For the Indian mission everything is virtually for the first time. For NASA and the US, the MAVEN mission which is due to launch on Monday 18th November is the 15th Mission to Mars. The first mission (Mariner 3) failed and the second mission, Mariner 4, launched in November 1964 was the first to reach Mars. In the 49 years since there have been a few failures (Mariner 8 in 1971, Mars Observer 1992, Mars Climate Orbiter in 1998 and the Mars Polar lander/Deep Space2 in 1999) and some spectacular successes for NASA with the Mars Global Surveyor in 1996 , the Phoenix Mars Lander in 2007 and the Mars Rover in 2011.

Many Mars missions have failed. Between 1960 and 1971 the Russians (USSR) failed in 11 attempts to send a spacecraft to the vicinity of Mars. The 12th attempt with M-71 in 1971 succeeded in orbiting Mars. Of eight further attempts by Russia, 4 failed to reach Mars. The Japanese Nozomi failed while cruising. Two European missions led to one orbiter (but a failed landing) and one flyby.

On the surface they may both seem to be similar in that both are attempting to get a spacecraft into orbit around Mars. But the missions are, in reality, quite different. MOM is essentially a first-time test of technology and capability whereas MAVEN is primarily a scientific mission utilising the deployment of now well proven US technology. Technology development on the one hand and a scientific investigation on the other.

1. NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) is a space probe designed to study the Martian atmosphere while orbiting Mars. India’s Mars Orbiter Mission (MOM – “Mangalyaan”) is a space probe designed to explore Mars’ surface features, morphology, mineralogy and Martian atmosphere using indigenous scientific instruments while orbiting Mars.

2. MAVEN is expected to have a budget of about $672 million. MOM has a budget of about $70 million.

3. The Atlas 5 rocket to be used to launch MAVEN has the capability to lift about 7,000 kg directly into a Geostationary transfer orbit (GTO). This allows MAVEN (2500 kg) to be injected directly into a Trans-Mars trajectory from launch.

The PSLV to be used for MOM can lift about 1300 kg into a GTO. With the MOM having a mass of 1337 kg, it becomes necessary for a  launch first into earth orbit and then a multi-step transition  through ever increasing earth orbits and finally into a Trans-Mars trajectory.

4. MAVEN is due to launch on an Atlas 5 rocket at 1:28 p.m. EST (1828 GMT) on Monday (Nov. 18) from Florida’s Cape Canaveral Air Force Station. Within one hour of launch MAVEN will be in a Hohmann Transfer Orbit with periapsis at Earth’s orbit and apoapsis at the distance of the orbit of Mars. MAVEN should reach Mars orbit on 22nd September 2014.

MAVEN trajectory - NASA-LASP-JPL

MAVEN trajectory – NASA-LASP-JPL

Because of the relatively low payload capability of the PSLV for an interplanetary mission MOM will spend more than four weeks in earth orbit and has to be equipped with radiation shielding to endure the numerous passages through earth’s radiation Belts. MOM has fired its Liquid Motor six times – always when passing perigee to gradually increase the apogee of the orbit to work its way up to departing Earth orbit in a fuel-efficient manner. The sixth (including one correction) firing yesterday placed the spacecraft in a 600 by approx 193,000 kilometer orbit around Earth and sets up the proper perigee passage for the final engine burn that puts the vehicle onto its Trans-Martian Trajectory using s standard Hohmann Transfer Orbit on 30th November/ 1st December. MOM should reach Mars orbit on 24th September 2014 (2 days after MAVEN).

mangalyaan trajectory

mangalyaan trajectory

5. MAVEN’s body has a cubical shape of about 2.3 m x 2.3 m x 2 m high, spans a total of 11.4 m with its solar panels deployed and has a lift-off mass of  2,454 kg (including fuel) and has a dry payload of 903 kg.

Mangalyaan’s body is a cuboid measuring about 1.5 m per side, a span of 4.2 m with solar panels deployed and an initial mass of 1337 kg of which 852 kg is fuel.

MAVEN - MOM (NASA- ISRO)

MAVEN – MOM (NASA- ISRO)

6. MAVEN is carrying 8 main, highly sophisticated instruments. Neutral Gas and Ion Mass Spectrometer, Imaging Ultraviolet Spectrograph, Magnetometer, Solar Wind Electron Analyzer, SupraThermal And Thermal Ion Composition, Langmuir Probe and Waves antenna, Solar Energetic Particles, Solar Wind Ion Analyzer

Mangalyaan is carrying a camera, two spectrometers, a radiometer and a photometer. Together, they have a weight of about 15 kg.

7. MAVEN is targeting a science orbit of 150 by 6,200 Kilometers at an inclination of 75 degrees. It will perform measurements from a highly elliptical orbit around Mars over a period of one Earth year, with five “deep dips” at 150 km minimum altitude to sample the upper atmosphere.

Mangalyaan will be much further out and targets an operational orbit of 365 by 80,000 Kilometers with an inclination of 150 degrees and a duration of 76.72 hours from where it will perform its science mission. The MOM mission in Mars orbit is open-ended and is expected to last about 160 days.

8. MAVEN’s science phase features regular communication sessions. The spacecraft points its High Gain Antenna at Earth for high data rate communications twice per week with the exact timing depending on Deep Space Network visibility. Those comm sessions take place on Tuesday and Friday and have a duration of eight hours during which at least five hours of Earth pointing are required to downlink all science data and housekeeping telemetry. 

Mangalyaan is equipped with a 2.2-meter diameter High Gain Antenna which is a parabolic X-Band reflector antenna that is used for data downlink and command uplink. Science data and spacecraft telemetry is stored in two 16Gb Solid State Recorders aboard the vehicle for downlink during regular communications sessions. Low and Medium Gain Antennas are used for low-bandwidth communications such as command uplink and systems telemetry downlink.

As missions go, MAVEN represents a Mercedes “S” class to the Volkswagen that is MOM.

Mangalyaan - MOM (ISRO)

Mangalyaan – MOM (ISRO)

Sources: 

http://www.spaceflight101.com/

http://www.spaceflight101.com/mars-orbiter-mission.html

http://www.spaceflight101.com/maven-mission-profile.html

http://www.nasa.gov/missions/index.html#.UodLu8SkoYE

http://www.space.com/

http://www.isro.org/mars/home.aspx

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Posted in Engineering, India, Science, Space, US | 10 Comments »

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