This is one invasion that everyone is delighted about! Man invaded Mars again, with the giant Mars Science Laboratory, Curiosity, the new Mars Rover, landing on Mars today. The whole payload managed to touchdown on the Red Planet, maneuvering itself with utmost perfection. Remember, all of this happened when Earth was blind to whatever was happening on Mars!
Touchdown and cheers
Things worked out like clockwork. The projected times all matched the real times to a few seconds! If you were watching the live stream from the NASA/JPL control room, you’d know the atmosphere in the room as each stage of the rover was accomplished.
There was a loud cheer when the parachute was deployed, a louder one when the back heat shield separated from the main body and the loudest was reserved for when the rover touched down and the magic words ‘Touchdown confirmed’ were spoken out. The almost childish celebrations that ensued involved people hugging each other, clapping frantically and many breaking down in tears. The scene was one of the most emotional ones you’ll ever see – a perfect antidote to the misrepresentation of science and scientists as emotionless entities.
Images and cheers
The next loud cheer occurred when the Odyssey spacecraft took a grainy 64×64 pixel image, just 4 KB in size, showing one of the wheels of Curiosity on the Martian surface. Odyssey soon sent a higher resolution picture, 256×256 pixel wide. The next image was that of the shadow of Curiosity on the surface of Mars. Never have such tiny images generated so much cheer – and tears!
Here is a video of the control room, showing that dramatic scenes.
The new Mars Rover, Curiosity, is poised to land on the Red Planet at 0524 GMT on 6th August. There have been no reported delays or corrections for tomorrow. The final path corrections were made today, and now Curiosity is out there on its own. From the time the Rover, called Mars Science Laboratory or MSL, enters the atmosphere to the time it touches down, the whole world will hold its breath. This is to so-called “seven minutes of terror”.
In this article, I’ll give you everything you need to know about the landing – the time, the place and more. Buckle up!
Landing: The Time!
If everything goes smoothly, Curiosity should touch down at 0731 CET (Central European Time) or 0531 GMT. I will take you through these seven minutes before they happen in this article. The times (all in GMT) given below are all expected times as given by ESA and NASA:
Time: T–6 min, 41 sec; 05:24:34 AM
At an altitude of 125 km, the Curiosity payload sheds two 75-kg tungsten weights. This reduces the weight, but it still can’t fly. Perhaps Allen Chen, JPL’s operations for entry, was paraphrasing Douglas Adams when he said “We’re flying like a brick”. The spacecraft’s internal gyroscopes have to all coordinate to keep the spacecraft aimed at the Gale Crater. The target is barely 20 km across.
Time: T–5 min, 26 sec;
The Earthly package is in free-fall. The atmospheric drag increases the surface temperature to about 21000C. Carbon tiles, specially made to handle such high temperatures, protect the precious load inside. Curiosity is nestled safely inside this package.
Time: T–2 min, 28 sec; 05:28:46 AM
The parachute deploys! It’s nearly 16 meters in diameter! The hearts of all the NASA and ESA engineers are in their mouths. The parachutes are one of the parts most likely to fail, even though that failure possibility is quoted at 1%. This will be a real test for the parachutes, since they have only cushioned drops for much lighter payloads. The altitude from ground is 11km and the payload is still travelling faster than sound at an estimated 425 m/s.
Time: T–2 min, 4 sec; 05:29:07 AM
The heat shield separates! The payload starts sensing the ground approaching. The current altitude is just 8 km and the payload is now moving at 125 – 130 m/s, still too fast to make a proper landing. Crucially, three radar antennas switch on and this is how it knows how far the ground is. The data is useful for the craft to adjust its actions. For the first time, the craft has eyes and its guidance system can kick in.
Time: T– 53 sec; 05:30:40 AM
The back-shell separates. Finally, the world gets a glimpse of the new Rover! The back-shell flies off with the parachute! Curiosity drops down towards the surface, cushioned by the thrust of eight retrorockets. The altitude is less than 2 km from the surface and the craft is moving at a speed of 80 m/s.
Time: T–20 sec; 05:31:17 AM
The sky crane is deployed! This is a complete transformation from previous landings by NASA. So why this sudden transformation? Simple – Curiosity is just too heavy. This calls for a new arrangement – the wheel suspension system can be used as a landing gear. The main craft, Curiosity, then drops down as a thread unspools from the sky crane. The craft gently drops down at a nice pace of 0.75 m/s.
Time: T–0 sec; 05:31:37 AM
Landing: The Place
The site of the touchdown is Gale Crater. The crater is 154 km wide, but the target area is just 20 km. The High Resolution Stereo Camera (HRSC) on the Mars Express spacecraft has just sent back a very interesting picture of the landing area. The image is a false colour image as shown below:
The image suggests the presence of water-based minerals, which might form the basis of life. The lower elevated areas are shown in purple and this forms the target landing area. But don’t miss out on the elevation right in the middle – it’s called Mount Sharp and rises to 5.5 km above the crater floor. Scientists want the rover to land closest to this mountain, as the geologic features there are “very interesting”. The rover will land in the depression, scour around for interesting geologic artifacts and then trudge towards the elevation.
The Eyes and Ears of Curiosity
Meanwhile, the Mars Express will be eyes and ears of the Mars Science Laboratory. The Mars Express Lander Communication (MELACOM) will be switched on at 0205 GMT on 6th August, long before the touchdown.
M-Ex starts recording
Radio signals transmitted by the Mars Rover will be recorded by the Mars Express starting from 05:09 to 05:37 GMT. (For CET times, just add two hours.) This is when the MELACOM receiver switches off and the Mars Express starts off from the dark area of Mars to point at Earth.
M-Ex starts transmitting
The Mars Express starts transmitting recorded signals back to Earth at 06:10 AM (GMT). The data will be transmitted for over 40 minutes with the transmitter shutting down at about 06:42 AM. The only thing left to do for ESA is to transfer the data to NASA.
The Final Words
We’ll be there with you when the massive Mars Rover, weighing in at 900 kg, touches down on the surface. The leaps made have not only been in terms of the technology packed in the machine, but also in the new ways devised to land a very heavy craft precisely on the surface of another planet. The unexpected hurdle came in the form of the black out for the “seven minutes of terror”, during which Curiosity will land, but NASA will be completely blind to it.
So what can go wrong? Charles Bolden, NASA administrator, has a very simple answer – “All sorts of things can go wrong”.
What about all the simulations of worst-case scenarios, rigorous testing of each part and lessons learnt from previous missions? Shouldn’t they be enough? Steven lee, mission’s control systems manager, working in JPL has the perfect closing line:
Probably the overall biggest risk is our lack of imagination.
Europe is all set to launch the Galileo satellites its answer to the US GPS and Russian GLONASS on Friday, 21st October. The launch was supposed to have taken place early today (i.e. on 20th October), but unforeseen situations forced the launch to be shifted the next day. The satellites, a joint venture between European Space Agency and Roscosmos, will be launched using the Russian Soyuz rockets, marking the first use of Soyuz to launch a non-Russian payload.
Self-Reliance is the Keyword
The Galileo system will free up the European nations from their reliance on American technology for a reliable tracking system. The US GPS is available to all, but it can be discontinued or restricted in times of war. If not completely barred, the precision of the service might also be curtailed by the US. The US GPS is ultimately controlled mainly by the US military, which holds very high priority in the policy making corridors of America. Galileo will free Europe of all such constraints.
Galileo will provide both high precision and low precision services. The low precision facilities will be open to all. The high-precision facilities will be used primarily by the military.
Features of Galileo
Navigational and Search-And-Rescue facilities
The Galileo system has some really great features, as compared to the US GPS and the Russian GLONASS. It will be an array of 30 satellites (27 active ones and 3 spares) all in an orbit about 23,000 km above the Earth’s surface. The navigational precision of Galileo is rumored to be better than the US GPS, though the exact numbers are not yet known. Galileo will also be able to do Search-And-Rescue (SAR) operations. Users can send distress calls along with their positions via the Galileo system to emergency agencies. Galileo has the additional facility of user feedback it will tell the user whether the rescue team has been deployed or not and what their location might be.
Time measurement facility
Galileo will fly up with four high precision atomic clocks of two types. The first type is a hydrogen based maser clock, which is accurate to 0.45 ns in 12 hours (i.e. it slows down by 0.45 nanoseconds in 12 hours!!). the clock uses the super-stable 1.4 GHz hydrogen atom transition line to measure time. The second type of clocks – Rubidium clocks – serves as back-up. The Rubidium clock is accurate to within 1.8 ns over 12 hours. Ultra-precise time measurement is one of the fundamental necessities of a proper positional and navigational system.
Friction with Big Brother: Did the US plan to shoot Galileo down?
The US apparently planned to even shoot the Galileo satellites using missiles, since it feared that the facility might be used for military purposes against it. Tempers have cooled down and, with ESA declaring that the satellites won’t be used for spying, the US has no problem with the launch of the Galileo systems.
Named after the first real scientist, Galileo Galilee, the satellites aim to do what the great man always wanted to teach self-reliance in the matter of knowledge and thought.