Closing the Clamshell on a Martian Curiosity

In the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, sections of an Atlas V rocket payload fairing engulf NASA's Mars Science Laboratory (MSL) as they close in around it. The blocks on the interior of the fairing are components of the fairing acoustic protection (FAP) system, designed to protect the payload by dampening the sound created by the rocket during liftoff. Launch of MSL aboard a United Launch Alliance Atlas V rocket is planned for Nov. 25 from Space Launch Complex-41 on Cape Canaveral Air Force Station. Credit: NASA/Jim Grossmann

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Curiosity’s clamshell has been closed.

And it won’t open up again until a few minutes after she blasts off for the Red Planet in just a little more than 3 weeks from now on Nov. 25, 2011 – the day after Thanksgiving celebrations in America.

The two halves of the payload fairing serve to protect NASA’s next Mars rover during the thunderous ascent through Earth’s atmosphere atop the powerful Atlas V booster rocket that will propel her on a fantastic voyage of hundreds of millions of miles through interplanetary space.

Spacecraft technicians working inside the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center (KSC) in Florida have now sealed Curiosity and her aeroshell inside the payload fairing shroud. The fairing insulates the car sized robot from the intense impact of aerodynamic pressure and heating during ascent. At just the right moment it will peal open and be jettisoned like excess baggage after the rocket punches through the discernable atmosphere.

Clamshell-like payload fairing about to be closed around Curiosity at KSC. Credit: NASA/Jim Grossmann

The next trip Curiosity takes will be a few miles to the Launch Pad at Space Launch Complex 41 at adjacent Cape Canaveral Air Force Station. She will be gingerly loaded onto a truck for a sojourn in the dead of night.

Curiosity in front of one payload fairing shell. Credit: NASA/Jim Grossmann

“Curiosity will be placed onto the payload transporter on Tuesday and goes to Complex 41 on Wednesday, Nov. 2,” KSC spokesman George Diller told Universe Today. “The logo was applied to the fairing this weekend.”

At Pad 41, the payload will then be hoisted atop the United Launch Alliance Atlas V rocket and be bolted to the Centaur upper stage.

Installation of Curiosity’s MMRTG (Multi-Mission Radioisotope Thermoelectric Generator) power source is one of the very last jobs and occurs at the pad just in the very final days before liftoff for Mars.

The MMRTG will be installed through a small porthole in the payload fairing and the aeroshell (see photo below).

MMRTG power source will be installed on Curiosity through the porthole at right just days before Nov. 25 launch. Credit: NASA/Jim Grossmann

The plutonium dioxide based power source has more than 40 years of heritage in interplanetary exploration and will significantly enhance the driving range, scientific capability and working lifetime of the six wheeled rover compared to the solar powered rovers Spirit and Opportunity.

After a 10 month voyage, Curiosity is due to land at Gale Crater in August 2012 using the revolutionary sky crane powered descent vehicle for the first time on Mars.

Camera captures one last look at Curiosity before an Atlas V rocket payload fairing is secured around it. Credit: NASA/Jim Grossmann

Curiosity has 10 science instruments to search for evidence about whether Mars has had environments favorable for microbial life, including chemical ingredients for life. The unique rover will use a laser to look inside rocks and release the gasses so that its spectrometer can analyze and send the data back to Earth.

Technicians monitor Curiosity about to be engulfed by the two halves of the payload fairing. Credit: NASA/Jim Grossmann
Payload fairing sealed around Curiosity at the Payload Hazardous Servicing Facility at KSC. Credit: NASA/Jim Grossmann
Atlas V rocket at Launch Complex 41 at Cape Canaveral, Florida
An Atlas V rocket similar to this one utilized in August 2011 for NASA’s Juno Jupiter Orbiter will blast Curiosity to Mars on Nov. 25, 2011 from Florida. Credit: Ken Kremer

Phobos-Grunt, Earth’s other mission to Mars courtesy of Russia is due to blast off first from the Baikonur Cosmodrome on November 9, 2011.

Read Ken’s continuing features about Curiosity starting here:
Curiosity Buttoned Up for Martian Voyage in Search of Life’s Ingredients
Assembling Curiosity’s Rocket to Mars
Encapsulating Curiosity for Martian Flight Test
Dramatic New NASA Animation Depicts Next Mars Rover in Action

Read Ken’s continuing features about Russia’s Phobos-Grunt Mars mission here:
Russia Fuels Phobos-Grunt and sets Mars Launch for November 9
Phobos-Grunt and Yinghou-1 Arrive at Baikonur Launch Site to tight Mars Deadline
Phobos-Grunt: The Mission Poster
Daring Russian Sample Return mission to Martian Moon Phobos aims for November Liftoff

Curiosity Buttoned Up for Martian Voyage in Search of Life’s Ingredients

Curiosity Mars Science Laboratory (MSL)- all elements assembled into flight configuration in the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida. The top portion is the cruise stage attached to the aeroshell (containing the compact car-sized rover) with the heat shield on the bottom. Launch of MSL aboard a United Launch Alliance Atlas V rocket is scheduled for Nov. 25 from Space Launch Complex 41 on Cape Canaveral Air Force Station in Florida. Credit: NASA/Glenn Benson

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Take a good last, long look at the magnificent robot that is Curiosity, because she’s been all buttoned up for her long Martian voyage in search of the ingredients of life. After years of exhaustive work, the most technologically advanced surface robotic rover ever to be sent beyond Earth has been assembled into the flight configuration, a NASA spokesperson informed Universe Today.

The next time Curiosity opens her eyes she will have touched down at the foot of a layered mountain inside the planet’s Gale crater.

Curiosity Mars rover folded for flight and mated to the cruise stage. The cruise stage provides solar power, thrusters for navigation, and heat exchangers to the rover during its flight from Earth to Mars. Credit: NASA/Glenn Benson

Curiosity – NASA’s next Mars rover – is formally known as the Mars Science Laboratory (or MSL) and has entered the final stages of preflight processing.

After extensive quality assurance testing, Curiosity has been encapsulated for the final time inside the aeroshell that will be her home during the 10 month long interplanetary cruise to Mars. Furthermore, she’s been attached to the cruise stage that will guide her along the path from the home planet to the red planet.

Curiosity Mars Science Laboratory (MSL) assembled into flight configuration in the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center in Florida. The rover Curiosity has 10 science instruments designed to search for evidence on whether Mars has had environments favorable to microbial life, including chemical ingredients for life. Credit: NASA/Glenn Benson

The work to combine all the components into an integrated assembly was carried out inside the clean room facilities of the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center (KSC) in Florida.

The aeroshell is comprised of the heat shield and back shell.

The job of the aeroshell is to protect Curiosity from the intense heat of several thousand degrees F(C) generated by friction as the delicate assemblage smashes into the Martian atmosphere at about 13,200 MPH (5900 m/s) and plummets some 81 miles during the terrifying seven minute long entry, descent and landing (EDL) on the surface.

See Video animation below

The massive 2000 lb (900 kg) rover is folded up and mated to the back shell powered descent vehicle, known as the PDV or Sky Crane. The spacecraft is designed to steer itself through a series of S-curve maneuvers to slow the spacecraft’s descent through the Martian atmosphere.

In the final moments, the rocket powered Sky crane will lower the robot on tethers and then safely set Curiosity down onto the ground at a precise location inside the chosen landing site astride a layered mountain in Gale Crater believed to contain phyllosilicate clays and hydrated sulfate minerals that formed in liquid water.

The robot is the size of a compact car and measures three meters in length, roughly twice the size of the MER rovers; Spirit and Opportunity. It is equipped with 10 science instruments for a minimum two year expedition across Gale crater.

NASA's Curiosity Mars Science Laboratory Rover
Inside the Clean room at the Payload Hazardous Servicing Facility at the Kennedy Space Center.
The science payload weighs ten times more than any prior Mars rover mission. Curiosity will zap rocks with a laser and deftly maneuver her outstretched robotic arm to retrieve and analyze dozens of Martian soil samples. Credit: Ken Kremer

Curiosity will search for the ingredients of life including water and organic molecules and environmental conditions that could have been hospitable to sustaining Martian microbial life forms if they ever existed in the past or survived to the present through dramatic alterations in Mars climatic and geologic history.

Liftoff of the $2.5 Billion Curiosity rover is slated for Nov. 25 from Cape Canaveral Air Force Station in Florida on a United Launch Alliance Atlas V booster rocket. The launch window to Mars extends until Dec. 18.

This coming week, Curiosity will be encapsulated into the clamshell like payload fairing and the MSL logo will then be applied to the fairing, KSC spokesman George Diller told Universe Today. It will then be hoisted onto the payload transporter and carefully conveyed to Space Launch Complex 41 on Nov. 2, for mating atop the Atlas V rocket.

Mars Science Laboratory Aeroshell with Curiosity enclosed inside. Credit: NASA

Read Ken’s continuing features about Curiosity starting here:
Assembling Curiosity’s Rocket to Mars
Encapsulating Curiosity for Martian Flight Test
Dramatic New NASA Animation Depicts Next Mars Rover in Action

Read Ken’s features about Russia’s upcoming Phobos-Grunt, Earth’s other 2011 Mars mission here::
Phobos-Grunt and Yinghou-1 Arrive at Baikonur Launch Site to tight Mars Deadline
Phobos-Grunt: The Mission Poster
Daring Russian Sample Return mission to Martian Moon Phobos aims for November Liftoff

Assembling Curiosity’s Rocket to Mars

The first stage of the Atlas V rocket for NASA's Mars Science Laboratory (MSL) mission is lifted into an upright position for placement inside the Vertical Integration Facility at Space Launch Complex 41 on Cape Canaveral Air Force Station. A United Launch Alliance Atlas V-541 configuration will be used to loft MSL into space. NASA/Jim Grossmann

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Assembly of the powerful Atlas V booster that will rocket NASA’s Curiosity Mars Science Laboratory rover to Mars is nearly complete. The Atlas V is taking shape inside the Vertical Integration Facility at Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida.

The rocket is built by United Launch Alliance under contract to NASA as part of NASA’s Launch Services Program to loft science satellites on expendable rockets.

At Launch Complex 41 at Cape Canaveral Air Force Station in Florida, workers guide an overhead crane as it lifts the Centaur upper stage for the United Launch Alliance Atlas V in the Vertical Integration Facility (VIF). Once in position, it will be attached to the Atlas V booster stage, already at the pad. Credit: NASA/Jim Grossmann

The Atlas V configuration for Curiosity is similar to the one used for Juno except that it employs one less solid rocket motor in a designation known as Atlas 541.

4 indicates a total of four solid rocket motors are attached to the base of the first stage vs. five solids for Juno. 5 indicates a five meter diameter payload fairing. 1 indicates use of a single engine Centaur upper stage.

Blastoff of Curiosity remains on schedule for Nov. 25, 2011, the day after the Thanksgiving holiday in the U.S. The launch window for a favorable orbital alignment to Mars remains open until Dec. 18 after which the mission would face a 26 month delay at a cost likely to be in the hundreds of millions of dollars.

Curiosity is set to touchdown on Mars at Gale Crater between August 6 & August 20, 2012. The compact car sized rover is equipped with 10 science instruments that will search for signs of habitats that could potentially support martian microbial life, past or present if it ever existed.

At the Vertical Integration Facility (VIF) at Launch Complex 41 at Cape Canaveral Air Force Station in Florida, the Centaur upper stage for the United Launch Alliance Atlas V is in position in the Vertical Integration Facility (VIF). It then will be attached to the Atlas V booster stage, already at the pad. The Atlas V is slated to launch NASA's Mars Science Laboratory (MSL) mission - the compact car-sized Curiosity Mars rover. Credit: NASA
With a unique view taken from inside Vertical Integration Facility (VIF) at Launch Complex 41 at Cape Canaveral Air Force Station in Florida, an overhead crane lifts the Centaur upper stage for the United Launch Alliance Atlas V. Once in position in the VIF it will be attached to the Atlas V booster stage, already at the pad. NASA/Jim Grossmann
Workers guide an overhead crane as it lifts the Centaur upper stage for the United Launch Alliance Atlas V into the Vertical Integration Facility (VIF). NASA/Jim Grossmann
An overhead crane lifts the Centaur upper stage for the Atlas V. NASA/Jim Grossmann
The final solid rocket motor (SRM) hangs in an upright position for mating to a United Launch Alliance Atlas V rocket. NASA/Jim Grossmann
A crane lifts the 106.5-foot-long first stage of the Atlas V rocket for NASA's Mars Science Laboratory (MSL) mission through the open door of the Vertical Integration Facility at Space Launch Complex 41. Credit: NASA/Cory Huston
Curiosity Mars Science Laboratory Rover - inside the Cleanroom at KSC. Credit: Ken Kremer

Meanwhile NASA’s Opportunity Mars rover is nearing 8 continuous years of Exploration and Discovery around the Meridiani Planum region of the Red Planet.

Read Ken’s continuing features about Curiosity and Opportunity starting here:
Encapsulating Curiosity for Martian Flight Test
Dramatic New NASA Animation Depicts Next Mars Rover in Action
Opportunity spotted Exploring vast Endeavour Crater from Mars Orbit
Twin Towers 9/11 Tribute by Opportunity Mars RoverNASA Robot arrives at ‘New’ Landing Site holding Clues to Ancient Water Flow on Mars
Opportunity Arrives at Huge Martian Crater with Superb Science and Scenic Outlook
Opportunity Snaps Gorgeous Vistas nearing the Foothills of Giant Endeavour Crater
Opportunity Rover Heads for Spirit Point to Honor Dead Martian Sister; Science Team Tributes

Encapsulating Curiosity for Martian Flight Test

NASA’s Curiosity Mars Science Laboratory Rover inside the entry aeroshell. At the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, the "back shell powered descent vehicle" configuration, containing NASA's Mars Science Laboratory rover, Curiosity, is being placed on the spacecraft's heat shield. Credit: NASA/JPL-Caltech

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With just over 6 weeks to go until the liftoff of Curiosity – NASA’s next Mars rover – prelaunch processing at the Kennedy Space Center (KSC) in Florida is rapidly entering the home stretch. Technicians placed the folded rover inside the complete aeroshell to match the Martian entry configuration components together and conduct preflight testing of the integrated assembly at the Payload Hazardous Servicing Facility at KSC. The aeroshell is comprised of the heat shield and back shell and encapsulates Curiosity during the long voyage to Mars.

The job of the aeroshell is to protect the Curiosity Mars Science Laboratory (MSL) from the intense heat of several thousand degrees F(C) generated by friction as the delicate assemblage smashes into the Martian atmosphere during the terrifying entry and descent to the surface.

Curiosity Mars Science Laboratory Rover - inside the Cleanroom at KSC. Credit: Ken Kremer

The rover itself has been mated to the back shell powered descent vehicle, known as the PDV or sky crane. The rocket powered descent stage (PDV) is designed to maneuver through the Martian atmosphere, slow the descent and safely set Curiosity down onto the surface at a precise location inside the chosen landing site of Gale Crater.

Technicians still have several more weeks of hardware testing and planetary protection checks ahead before NASA’s minivan sized Martian robot is encapsulated inside the aeroshell for the final time.

Rotating Curiosity's Back Shell Powered Descent Vehicle
At the Payload Hazardous Servicing Facility at the Kennedy Space Center in Florida, the "back shell powered descent vehicle" configuration of NASA's Mars Science Laboratory is being rotated for final closeout actions. At this time Curiosity and its rocket-powered descent stage have already been integrated, and are now encapsulated inside the spacecraft's back shell. The configuration of rover integrated with the descent stage is the "powered descent vehicle." The back shell, a protective cover, carries the parachute and several other components used during descent. The yellow disks visible at the top of the configuration are the descent stage's radar antennas that will be used to calculate the rover's descent speed and altitude. Credit: NASA/JPL-Caltech

Another major task still to be completed is mating the aeroshell to the cruise stage and then fueling of the cruise stage, which guides MSL from the Earth to Mars, according to Guy Webster, press spokesman for NASA’s Jet Propulsion Laboratory which manages the MSL project for NASA.

The launch of the $2.5 Billion Curiosity rover atop an Atlas V rocket is slated for Nov. 25, the day after Thanksgiving, and the launch window extends until Dec. 18. Arrival at Gale crater is set for August 2012.

Curiosity is by far the most scientifically advanced surface robotic rover ever sent beyond Earth and will search for environmental conditions that could have been favorable to support Martian microbial life forms if they ever existed in the past or present.

Final Closeout Actions for Curiosity's Heat Shield and Back Shell
At the Payload Hazardous Servicing Facility at NASA's Kennedy Space Center in Florida, the "back shell powered descent vehicle" configuration, containing NASA's Mars Science Laboratory rover, Curiosity, is being rotated for final closeout actions. The flat, circular object in the foreground of the image is the spacecraft's heat shield. The heat shield and the back shell will together form an encapsulating aeroshell that will protect the rover from the intense heat and friction that will be generated as the flight system descends through the Martian atmosphere.Credit: NASA/JPL-Caltech

Watch for my upcoming report from inside the cleanroom with Curiosity.
Read Ken’s continuing features about Curiosity and Opportunity starting here:
Opportunity spotted Exploring vast Endeavour Crater from Mars Orbit
Twin Towers 9/11 Tribute by Opportunity Mars RoverNASA Robot arrives at ‘New’ Landing Site holding Clues to Ancient Water Flow on Mars
Opportunity Arrives at Huge Martian Crater with Superb Science and Scenic Outlook
Opportunity Snaps Gorgeous Vistas nearing the Foothills of Giant Endeavour Crater
Dramatic New NASA Animation Depicts Next Mars Rover in Action
Opportunity Rover Heads for Spirit Point to Honor Dead Martian Sister; Science Team Tributes

Dramatic New NASA Animation Depicts Next Mars Rover in Action

NASA's Mars Science Laboratory Curiosity rover. Curiosity is a mobile robot for investigating Mars' past or present ability to sustain microbial life. Curiosity is being tested in preparation for launch in the fall of 2011. The mast, or rover's "head," rises to about 2.1 meters (6.9 feet) above ground level, about as tall as a basketball player. This mast supports two remote-sensing instruments: the Mast Camera, or "eyes," for stereo color viewing of surrounding terrain and material collected by the arm; and, the ChemCam instrument, which is a laser that vaporizes material from rocks up to about 9 meters (30 feet) away and determines what elements the rocks are made of. Credit: NASA/JPL-Caltech. New NASA High Resolution Curiosity Animations below

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NASA’s next Mars rover, the Curiosity Mars Science Laboratory, will soon embark on a quantum leap in humankind’s scientific exploration of the Martian surface -the most Earthlike planet in our Solar System.

To get a birds eye understanding of Curiosity’s magnificent capabilities, check out the dramatic new high resolution animation below which depicts NASA’s next Mars rover traversing tantalizing terrain for clues to whether Martian microbial life may have existed, evolved and been sustained in past or present times.


The new action packed animation is 11 minutes in length. It depicts sequences starting with Earth departure, smashing through the Martian atmosphere, the nail biting terror of the never before used rocket-backpack sky crane landing system and then progressing through the assorted science instrument capabilities that Curiosity will bring to bear during its minimum two year expedition across hitherto unseen and unexplored Martian landscapes, mountains and craters.

Curiosity is equipped with 10 science instruments. The three meter long robot is five times the weight of any previous Mars rover.

Those who closely follow the adventures of NASA’s Spirit and Opportunity rovers, like myself, will quickly recognize several of the panoramic scenes which have been included to give a realistic feeling of vistas to expect from the car sized Curiosity rover.

Here is a shorter 4 minute animation with expert narration


Along the way you’ll experience Curiosity zapping rocks with a laser, deftly maneuvering her robotic arm and camera mast and retrieving and analyzing Martian soil samples.

“It is a treat for the 2,000 or more people who have worked on the Mars Science Laboratory during the past eight years to watch these action scenes of the hardware the project has developed and assembled,” said Mars Science Laboratory Project Manager Pete Theisinger at NASA’s Jet Propulsion Laboratory, Pasadena, Calif, in a NASA statement. “The animation also provides an exciting view of this mission for any fan of adventure and exploration.”

Curiosity - The Next Mars Rover analyzes Martian rocks
Curiosity rover examines a rock on Mars with a set of tools at the end of the rover's arm, which extends about 2 meters (7 feet). Two instruments on the arm can study rocks up close. Also, a drill can collect sample material from inside of rocks and a scoop can pick up samples of soil. The arm can sieve the samples and deliver fine powder to instruments inside the rover for thorough analysis. Credit: NASA/JPL-Caltech

Curiosity was flown this week from her birthplace at NASA’s Jet Propulsion Laboratory in California to her future launch site in Florida aboard a C-17 military cargo transport aircraft.

She arrived at the Shuttle Landing Facility (SLF) at the Kennedy Space Center on June 22. The SLF is the same landing strip where I watched the STS-135 crew arrive for NASA’s final shuttle mission just days earlier days for their final launch countdown training.

NASA has scheduled Curiosity to blast off for the red planet on Nov. 25, 2011 from Cape Canaveral Air Force Station aboard an Atlas V rocket. Curiosity will touchdown in August 2012 at a landing site that will be announced soon by Ed Weiler, NASA Associate Administrator for the Science Mission Directorate in Washington, D.C.

Curiosity rover traverses new Martian terrain in search of habitats for microbial life. Credit: NASA/JPL-Caltech

Read my prior features about Curiosity
Packing a Mars Rover for the Trip to Florida; Time Lapse Video
Test Roving NASA’s Curiosity on Earth
Curiosity Mars Rover Almost Complete
Curiosity Rover Testing in Harsh Mars-like Environment

Packing a Mars Rover for the Trip to Florida

Check out this way cool time-lapse movie of NASA’s Curiosity Mars rover as its being packed up for her trip to Florida.

The video covers a 4 day period from June 13 to 17 and is condensed to just 1 minute. Watch the JPL engineers and technicians prepare Curiosity and the descent stage for shipping to the Kennedy Space Center in Florida and place it inside a large protective shipping container. Continue reading “Packing a Mars Rover for the Trip to Florida”

Watch a Mars Rover Under Construction – LIVE!

If you are tired of the drama of your favorite reality TV show, it might be time to switch things up a bit. The most recent reality show, available ad free on the internet, features a spunky robot and a huge cast of characters. The spunky robot is Curiosity, the name of the Mars Science Laboratory rover. The characters are all wearing white clean room “bunny suits,” so it will be difficult to tell them apart. Surely, if you spend enough time watching you’ll be able to discern who’s who.

In all seriousness, you can watch the construction of Curiosity live via Ustream. The NASA/JPL team that is constructing the rover will be at work between 8 a.m. to 11:00 p.m. PDT Monday through Friday. Otherwise, things will be a little quiet. The camera looks out onto a pretty active part of the clean room, but they may move the rover outside of the view of the camera. Some of the busy periods will be archived at the bottom of the Ustream feed, so if you end up watching during a quiet period, take a look at those while you’re waiting for the next work period to start up.

For more on the rover and its mission, visit the mission page or see our story on Universe Today from September, “5 Things about the Next Mars Rover“.

Source: JPL

Astronomy Without A Telescope – Solar Or RTG?

The 'edge of the envelope' solar powered Juno mission - scheduled for launch in 2011.

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It used to be the case that if you wanted to send a spacecraft mission out past the asteroid belt, you’d need a chunk of plutonium-238 to generate electric power – like for Pioneers 10 and 11, Voyagers 1 and 2, Galileo, Cassini, even Ulysses which just did a big loop out and back to get a new angle on the Sun – and now New Horizons on its way to Pluto.

But in 2011, the Juno mission to Jupiter is scheduled for launch – the first outer planet exploration mission to be powered by solar panels. And also scheduled for 2011, in another break with tradition – Curiosity, the Mars Science Laboratory will be the first Mars rover to be powered by a plutonium-238 radioisotope thermoelectric generator – or RTG.

I mean OK, the Viking landers had RTGs, but they weren’t rovers. And the rovers (including Sojourner) had radioisotope heaters, but they weren’t RTGs.

So, solar or RTG – what’s best? Some commentators have suggested that NASA’s decision to power Juno with solar is a pragmatic one – seeking to conserve a dwindling supply of RTGs – which have a bit of a PR problem due to the plutonium.

However, if it works, why not push the limits of solar? Although some of our longest functioning probes (like the 33 year old Voyagers) are RTG powered, their long-term survival is largely a result of them operating far away from the harsh radiation of the inner solar system – where things are more likely to break down before they run out of power. That said, since Juno will lead a perilous life flying close to Jupiter’s own substantial radiation, longevity may not be a key feature of its mission.

Perhaps RTG power has more utility. It should enable Curiosity to go on roving throughout the Martian winter – and perhaps manage a range of analytical, processing and data transmission tasks at night, unlike the previous rovers.

With respect to power output, Juno’s solar panels would allegedly produce a whopping 18 kilowatts in Earth orbit, but will only manage 400 watts in Jupiter orbit. If correct, this is still on par with the output of a standard RTG unit – although a large spacecraft like Cassini can stack several RTG units together to generate up to 1 kilowatt.

So, some pros and cons there. Nonetheless, there is a point – which we might position beyond Jupiter’s orbit now – where solar power just isn’t going to cut it and RTGs still look like the only option.

Left image: a plutonium-238 ceramic pellet glowing red hot, like most concentrated ceramicised radioisotopes will do. Credit: Los Alamos National Laboratory. Right image: the Apollo 14 ALSEP RTG, almost identical to Apollo 13's RTG which re-entered Earth's atmosphere with the demise of the Aquarius lunar module. Credit: NASA

RTGs take advantage of the heat generated by a chunk of radioactive material (generally plutonium 238 in a ceramic form), surrounding it with thermocouples which use the thermal gradient between the heat source and the cooler outer surface of the RTG unit to generate current.

In response to any OMG it’s radioactive concerns, remember that RTGs travelled with the Apollo 12-17 crews to power their lunar surface experiment packages – including the one on Apollo 13 – which was returned unused to Earth with the lunar module Aquarius – the crew’s life boat until just before re-entry. Allegedly, NASA tested the waters where the remains of Aquarius ended up and found no trace of plutonium contamination – much as expected. It’s unlikely that its heat tested container was damaged on re-entry and its integrity was guaranteed for ten plutonium-238 half-lives, that is 900 years.

In any case, the most dangerous thing you can do with plutonium is to concentrate it. In the unlikely event that an RTG disintegrates on Earth re-entry and its plutonium is somehow dispersed across the planet – well, good. The bigger worry would be that it somehow stays together as a pellet and plonks into your beer without you noticing. Cheers.

Curiosity Rover Takes First Test Drive

Even though there were no wheelies or skid marks, it was an exciting day for the teams working on the next Mars rover. The Mars Curiosity rover (or the Mars Science Laboratory) took its first short drive in the JPL clean room where it is being built. This video was captured from live broadcast on July 23, 2010. Cheers and commentary provided by mission team members who watched the event from a viewing gallery above the clean room floor. In this clip the rover drives backward for the first time.

Launch Dates Narrowed for Mars Science Lab

This artist's concept from an animation depicts Curiosity, the rover to be launched in 2011 by NASA's Mars Science Laboratory, as it is being lowered by the mission's rocket-powered descent stage during a critical moment of the "sky crane" landing in 2012. Image Credit: NASA/JPL-Caltech

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Mission planners have narrowed the field for possible launch dates for NASA’s next generation rover to Mars, the Mars Science Laboratory, nicknamed Curiosity. Taking into account orbital mechanics, planetary alignment, and communications issues, MSL’s launch will occur between Nov. 25 and Dec. 18, 2011, with landing will taking place between Aug. 6 and Aug. 20, 2012. The actual landing site is still being decided, between four different locations on Mars (read about the four sites here.)

“The key factor was a choice between different strategies for sending communications during the critical moments before and during touchdown,” said Michael Watkins, mission manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “The shorter trajectory is optimal for keeping both orbiters in view of Curiosity all the way to touchdown on the surface of Mars. The longer trajectory allows direct communication to Earth all the way to touchdown.”

Landing on Mars is always very difficult, and NASA has put a high priority on communication during Mars landings, especially after a landing failure in 1999. Therefore, the flight schedule allows for favorable positions for the Mars Odyssey and the Mars Reconnaissance Orbiter, currently orbiting Mars, which can both obtain information during descent and landing of MSL.

The simplicity of direct-to-Earth communication from Curiosity during landing has appeal to mission planners, but the direct-to-Earth option allows a communication rate equivalent to only about 1 bit per second, while the relay option allows about 8,000 bits or more per second.

“It is important to capture high-quality telemetry to allow us to learn what happens during the entry, descent and landing, which is arguably the most challenging part of the mission,” said Fuk Li, manager of NASA’s Mars Exploration Program at JPL. “The trajectory we have selected maximizes the amount of information we will learn to mitigate any problems.”

Curiosity will use several innovations during entry, descent and landing in order to hit a relatively small target area on the surface and set down a rover too heavy for the cushioning air bags used in earlier Mars rover landings. MSL will use employ of the largest parachutes ever used in a space mission to land a car-sized rover on the Red Planet. Most interesting is the final phase of landing, where a “sky-crane,” a rocket-powered descent stage will lower Curiosity on a tether for a wheels-down landing directly onto the surface.

Even though Curiosity won’t be communicating directly with Earth at touchdown, data about the landing will reach Earth promptly. Odyssey will be in view of both Earth and Curiosity, in position to immediately forward to Earth the data stream it is receiving during the touchdown. Odyssey performed this type of “bent-pipe” relay during the May 25, 2008, arrival of NASA’s Phoenix Mars Lander.

Curiosity will rove extensively on Mars, carrying an analytical laboratory and other instruments to examine a carefully selected landing area. It will investigate whether conditions there have favored development of microbial life and its preservation in the rock record. Plans call for the mission to operate on Mars for a full Martian year, which is equivalent to two Earth years.

More information about NASA’s Mars Science Laboratory.

Source: JPL