NASA's Curiosity rover looks across a rock field in this raw picture from Mars taken Aug. 8, 2014. Credit: NASA/JPL-Caltech
This picture alone illustrates the challenge NASA has as it slowly moves the Curiosity rover across Mars to its mountainous destination. You can see rocks surrounding the rover on Sol 713 (on Aug. 8), which is a challenge because of the ongoing wear and tear on Curiosity’s aluminum wheels.
In mid-July, Curiosity crossed one of the most difficult stretches of terrain yet since NASA spotted the damage and took measures to mitigate further problems, which includes picking out the smoothest terrain possible for its rover — which just celebrated two years on the Red Planet.
“For about half of July, the rover team at NASA’s Jet Propulsion Laboratory in Pasadena, California, drove Curiosity across an area of hazardous sharp rocks on Mars called ‘Zabriskie Plateau’,” NASA wrote in a recent press release.
A closeup of Curiosity’s wheels on Mars on Aug. 9, 2014. Credit: NASA/JPL-Caltech
“Damage to Curiosity‘s aluminum wheels from driving across similar terrain last year prompted a change in route, with the plan of skirting such rock-studded terrain wherever feasible. The one-eighth mile (200 meters) across Zabriskie Plateau was one of the longest stretches without a suitable detour on the redesigned route toward the long-term science destination.”
The rover is planning to make its way up the slope of science destinations on Mount Sharp, which is about two miles (3 kilometers) away. NASA pointed out that an interim stop for the rover will take place less than a third of a mile away (500 meters).
“The wheels took some damage getting across Zabriskie Plateau, but it’s less than I expected from the amount of hard, sharp rocks embedded there,” added Jim Erickson, project manager for Curiosity at NASA’s Jet Propulsion Laboratory, in a statement.
A low view of the terrain taken by the Mars Curiosity rover in August 2014. Credit: NASA/JPL-Caltech
“The rover drivers showed that they’re up to the task of getting around the really bad rocks. There will still be rough patches ahead. We didn’t imagine prior to landing that we would see this kind of challenge to the vehicle, but we’re handling it.”
Curiosity has driven out of its landing ellipse and will continue the trek to the mountain, stopping to perform science along the way.
NASA plans to heavily borrow from Curiosity’s design for its next rover, called Mars 2020. The science instruments for that rover were selected last week. While Curiosity was made to seek potentially habitable environments in the past or present, Mars 2020 will have the capability to search for organic materials that could indicate precursors to life.
The Mars Curiosity rover leaves tracks in the sand in this picture taken Aug. 9, 2014. Credit: NASA/JPL-CaltechA shadow of Mars Curiosity lies across the surface in this picture taken Aug. 9, 2014. Credit: NASA/JPL-Caltech
An artist's conception of the European Space Agency's ExoMars rover, scheduled to launch in 2018. Credit: ESA
Scientists, start your engines. The next few weeks will see a flurry of proposals come for the European Space Agency’s first rover mission on the Red Planet in 2018.
The ExoMars mission will see a lander and rover touch Mars, and what’s neat about this particular mission is the rover has a drill on board that can burrow as far down as 6 feet (2 meters) — a first on that planet. This means the mission would be well-suited to look for organic molecules, especially in light of the stunning findings Mars Curiosity scientists recently presented about a possibly life-friendly ancient lake on Mars.
Here, in ESA’s words, are what the site must accomplish:
The site must be ancient (older than 3.6 Ga)—from Mars’ early, habitable period: Pre- to late-Noachian (Phyllosian), possibly extending into the Hesperian;
The site must show abundant morphological and mineralogical evidence for long-duration, or frequently reoccurring, aqueous activity;
The site must include numerous sedimentary rock outcrops;
The outcrops must be distributed over the landing ellipse to ensure that the rover can get to some of them (typical rover traverse range is a few km);
The site must have little dust coverage.
If you’re well-versed in Red Planet geology, we’d love to hear your idea for possible sites. Feel free to leave your thoughts in the comments. For more information about the mission requirements, you can check out the ESA page, which details what proposals must contain.
A still from a Mars Curiosity panorama stitched together from NASA images. Credit: Andrew Bodrov, from NASA/JPL-Caltech/MSSS images
Here’s a nice distraction to start off the day: pretend you’re playing in the sandbox of Mars alongside Curiosity. This new panorama shows the NASA Rover hanging out somewhat nearby Mount Sharp (Aeolis Mons), its ultimate destination for the two-year prime mission it’s currently on.
“The images for panorama [were] obtained by the rover’s 34-millimeter Mast Camera,” wrote Andrew Bodrov on a blog post describing his work. “The mosaic, which stretches about 30,000 pixels’ width, includes 101 images taken on Sol 437.”
Bodrov, who is from Estonia, frequently does space-related panoramas. We wrote about a couple of other Curiosity panoramas he did in March 2013, in February 2013 and August 2012.
Last year, he told Universe Today that he has used PTGui panoramic stitching software from New House Internet Services BV to accomplish the stunning views.
He also has a wealth of images from the Baikonur Cosmodrome, which is the launch site for Soyuz spacecraft missions.
“It’s very nice to see the achievements of humanity which allows you to see a picture of another world,” Bodrov said in 2012.
Artist's conception of NASA's Mars Reconnaissance Orbiter. Credit: NASA/JPL
Imagine being able to watch three months’ worth of high-definition space video sequentially — maybe real-time coverage on the International Space Station, or getting to watch the Mars Reconnaissance Orbiter zoom across the Red Planet over and over again. Well, that’s how much science data MRO itself has sent back in 10 years of operations, NASA said.
“The sheer volume is impressive, but of course what’s most important is what we are learning about our neighboring planet,” stated the Jet Propulsion Laboratory’s Rich Zurek, the project scientist for the Mars Reconnaissance Orbiter.
MRO has sent back 200 terabits, all told. It’s a wealth of science data on its own merits as it examined evidence of water, ancient volcanoes and other parts of the Red Planet’s history from above. The spacecraft, however, also serves as a relay for the NASA Curiosity and Opportunity rovers on the surface.
A crater imaged by the Mars Reconnaissance Orbiter’s HiRISE (High Resolution Imaging Science Experiment). Credit: NASA/JPL/University of Arizona
“Data gathered by the orbiter’s instruments and relayed from rovers are recorded onto the orbiter’s central memory. Each orbit around Mars takes the spacecraft about two hours. For part of each orbit, Mars itself usually blocks the communication path to Earth,” NASA stated.
“When Earth is in view, a Deep Space Network antenna on whichever part of Earth is turned toward Mars at that hour can be listening. Complex preparations coordinate scheduling the use of the network’s antennas by all deep-space missions — 32 of them this month. Mars Reconnaissance Orbiter typically gets several sessions every day.”
Once the Deep Space Network antennas in Spain, California and Australia pick up the data, JPL organizes them into their separate “products”, ranging from radar measurements from above to data picked up by a rover below. The information is then sent to various organizations around the world that have interests in the work.
MRO arrived at Mars in 2006 and its mission has been extended three times, with the latest one taking place in 2012. NASA also relays information from the planet using Mars Odyssey, which has been there since 2002.
A marshmellow-sized Pu-238 pellet awaits a space mission. (Credit: The Department of Energy).
The end of NASA’s plutonium shortage may be in sight. On Monday March 18th, NASA’s planetary science division head Jim Green announced that production of Plutonium-238 (Pu-238) by the United States Department of Energy (DOE) is currently in the test phases leading up to a restart of full scale production.
“By the end of the calendar year, we’ll have a complete plan from the Department of Energy on how they’ll be able to satisfy our requirement of 1.5 to 2 kilograms a year.” Green said at the 44th Lunar and Planetary Science Conference being held in Woodlands, Texas this past Monday.
This news comes none too soon. We’ve written previously on the impending Plutonium shortage and the consequences it has for future deep space exploration. Solar power is adequate in most cases when you explore the inner solar system, but when you venture out beyond the asteroid belt, you need nuclear power to do it.
Production of the isotope Pu-238 was a fortunate consequence of the Cold War. First produced by Glen Seaborg in 1940, the weapons grade isotope of plutonium (-239) is produced via bombarding neptunium (which itself is a decay product of uranium-238) with neutrons. Use the same target isotope of Neptunium-237 in a fast reactor, and Pu-238 is the result. Pu-238 produces 280x times the decay heat at 560 watts per kilogram versus weapons grade Pu-239 and is ideal as a compact source of energy for deep space exploration.
Since 1961, over 26 U.S. spacecraft have been launched carrying Multi-Mission Radioisotope Thermoelectric Generators (MMRTG, or formerly simply RTGs) as power sources and have explored every planet except Mercury. RTGs were used by the Apollo Lunar Surface Experiments Package (ALSEP) science payloads left on by the astronauts on the Moon, and Cassini, Mars Curiosity and New Horizons enroute to explore Pluto in July 2015 are all nuclear powered.
Plutonium powered RTGs are the only technology that we have currently in use that can carry out deep space exploration. NASA’s Juno spacecraft will be the first to reach Jupiter in 2016 without the use of a nuclear-powered RTG, but it will need to employ 3 enormous 2.7 x 8.9 metre solar panels to do it.
The plutonium power source inside the Mars Science Laboratory’s MMRTG during assembly at the Idaho National Laboratory. (Credit: Department of Energy/Idaho National Laboratory image under a Creative Commons Generic Attribution 2.0 License).
The problem is, plutonium production in the U.S. ceased in 1988 with the end of the Cold War. How much Plutonium-238 NASA and the DOE has stockpiled is classified, but it has been speculated that it has at most enough for one more large Flag Ship class mission and perhaps a small Scout class mission. Plus, once weapons grade plutonium-239 is manufactured, there’s no re-processing it the desired Pu-238 isotope. The plutonium that currently powers Curiosity across the surface of Mars was bought from the Russians, and that source ended in 2010. New Horizons is equipped with a spare MMRTG that was built for Cassini, which was launched in 1999.
Technicians handle an RTG at the Payload Hazardous Servicing Facility at the Kennedy Space Center for the Cassini spacecraft. (Credit: NASA).
As an added bonus, plutonium powered missions often exceed expectations as well. For example, the Voyager 1 & 2 spacecraft had an original mission duration of five years and are now expected to continue well into their fifth decade of operation. Mars Curiosity doesn’t suffer from the issues of “dusty solar panels” that plagued Spirit and Opportunity and can operate through the long Martian winter. Incidentally, while the Spirit and Opportunity rovers were not nuclear powered, they did employ tiny pellets of plutonium oxide in their joints to stay warm, as well as radioactive curium to provide neutron sources in their spectrometers. It’s even quite possible that any alien intelligence stumbles upon the five spacecraft escaping our solar system (Pioneer 10 & 11, Voyagers 1 & 2, and New Horizons) could conceivably date their departure from Earth by measuring the decay of their plutonium power source. (Pu-238 has a half life of 87.7 years and eventually decays after transitioning through a long series of daughter isotopes into lead-206).
New Horizons in the Payload Hazardous Servicing Facility at the Kennedy Space Center. Note the RTG (black) protruding from the spacecraft. (Credit: NASA/Uwe W.)
The current production run of Pu-238 will be carried out at the Oak Ridge National Laboratory (ORNL) using its High Flux Isotope Reactor (HFIR). “Old” Pu-238 can also be revived by adding newly manufactured Pu-238 to it.
“For every 1 kilogram, we really revive two kilograms of the older plutonium by mixing it… it’s a critical part of our process to be able to utilize our existing supply at the energy density we want it,” Green told a recent Mars exploration planning committee.
Still, full target production of 1.5 kilograms per year may be some time off. For context, the Mars rover Curiosity utilizes 4.8 kilograms of Pu-238, and New Horizons contains 11 kilograms. No missions to the outer planets have left Earth since the launch of Curiosity in November 2011, and the next mission likely to sport an RTG is the proposed Mars 2020 rover. Ideas on the drawing board such as a Titan lake lander and a Jupiter Icy Moons mission would all be nuclear powered.
Engineers perform a fit check of the MMRTG on Curiosity at the Kennedy Space Center. The final installation of the MMRTG occurred the evening prior to launch. (Credit: NASA/Cory Huston).
Along with new plutonium production, NASA plans to have two new RTGs dubbed Advanced Stirling Radioisotope Generators (ASRGs) available by 2016. While more efficient, the ASRG may not always be the device of choice. For example, Curiosity uses its MMRTG waste heat to keep instruments warm via Freon circulation. Curiosity also had to vent waste heat produced by the 110-watt generator while cooped up in its aero shell enroute to Mars.
Cutaway diagram of the Advanced Stirling Radioisotope Generator. (Credit: DOE/NASA).
And of course, there are the added precautions that come with launching a nuclear payload. The President of the United States had to sign off on the launch of Curiosity from the Florida Space Coast. The launch of Cassini, New Horizons, and Curiosity all drew a scattering of protesters, as does anything nuclear related. Never mind that coal fired power plants produce radioactive polonium, radon and thorium as an undesired by-product daily.
An RTG (in the foreground on the pallet) left on the Moon by astronauts during Apollo 14. (Credit: NASA/Alan Shepard).
Said launches aren’t without hazards, albeit with risks that can be mitigated and managed. One of the most notorious space-related nuclear accidents occurred early in the U.S. space program with the loss of an RTG-equipped Transit-5BN-3 satellite off of the coast of Madagascar shortly after launch in 1964. And when Apollo 13 had to abort and return to Earth, the astronauts were directed to ditch the Aquarius Landing Module along with its nuclear-powered science experiments meant for the surface of the Moon in the Pacific Ocean near the island of Fiji. (They don’t tell you that in the movie) One wonders if it would be cost effective to “resurrect” this RTG from the ocean floor for a future space mission. On previous nuclear-equipped launches such as New Horizons, NASA placed the chance of a “launch accident that could release plutonium” at 350-to-1 against Even then, the shielded RTG is “over-engineered” to survive an explosion and impact with the water.
But the risks are worth the gain in terms of new solar system discoveries. In a brave new future of space exploration, the restart of plutonium production for peaceful purposes gives us hope. To paraphrase Carl Sagan, space travel is one of the best uses of nuclear fission that we can think of!
Curiosity's risky landing built on lessons learned from the mistakes of past missions, according to NASA. Credit: NASA
Mars is a graveyard; a spot where many a spacecraft slammed into the surface or perhaps, burned up in the atmosphere. This added drama to the Mars Curiosity rover landing last August.
Roger Gibbs, deputy manager for NASA’s Mars Exploration Program at the Jet Propulsion Laboratory, shared how NASA implemented “lessons learned” from Mars 6 (which died on this day in 1974) and other failed Mars missions when creating Curiosity’s game plan. We’ll get more into Curiosity in a moment, but here are the basic principles NASA uses.
Vigorous peer review. NASA wants its Mars teams to be close-knit. From working together and designing a challenging mission together, they form a common language that will serve them well during the challenging landing and mission. But that same closeness can lead to blind spots, so NASA undertakes regular peer reviews with scientists outside of the mission and sometimes even outside of the country. “The peers will come in. They are not vested in this. They haven’t become too engaged in that culture. They will ask pressing questions, and sometimes obnoxious and challenging questions,” Gibbs said.
Building for unknown dangers. Mars is an alien environment to NASA, not just because it’s outside of Earth but also because it has risks we may not know of. In the early days, some spacecraft miscalculated and grazed the atmosphere because we didn’t understand how much the thin gases expand in space, Gibbs said. So the engineers need to recalibrate the computer models with the latest information. “We model the atmosphere of Mars and say, what’s the density, what are the winds and speeds, how fast to change if a dust storm happens and the atmosphere warms up, and how much the atmosphere rises or”blooms.”
The Mars Polar Lander, which crashed and failed on Mars. Credit: NASA
Verifying and validating. Those words sound similar, but in NASA parlance they have entirely different meanings. Verification means they are making sure the design is meeting what they intend to meet. If NASA wants a change in velocity of 1,000 meters per second, for example, as the spacecraft inserts itself into orbit, it designs a system that can meet those specifications with fuel, thrusters and mass. The validation comes next. “It’s asking if 1,000 meters is the right number,” Gibbs said. “It’s a distinction that is sometimes lost on people, but it’s important.”
So how did this process help Curiosity? Well, this especially came to play when the team was designing the so-called “seven minutes of terror” — those final moments before the rover touched the ground. The team not only used parachutes, but also a device called a “sky crane” that used rockets and a sort of cable that lowered the rover carefully to the surface.
Imagine the measurements that must have taken, taking into account how different the Mars environment is from Earth. To gain understanding, the team reviewed again all the past mishap reports from failed Mars missions, such as the Mars Polar Lander and the European Space Agency’s Beagle 2.
Then, according to Gibbs, they spent “a lot of effort” on doing the verification and validation. Curiosity’s landing would be extremely difficult to model, but the team threw every bit of data they had in there.
The NASA team threw in every bit of data they could to model the Mars Curiosity landing. Credit: NASA
They created an atmospheric model of Mars, modelled the trajectory of the incoming spacecraft, and tried to figure out how the various systems would respond to the environment. Next, they tried to tweak the variables to see how far they could change without posing a danger to the mission.
“There’s a paranoia where the folks will ask, did we do it to the best of our knowledge,” Gibbs acknowledged. “What is it that we’re missing?”
If Curiosity had failed, NASA would have opened an inquiry board to figure out what had happened. These boards produce final reports that can be downloaded by anyone. Then, the agency would have tried to prevent the same situation from happening the next time a rover landed.
“It’s a lot easier to learn from someone else’s bad experience, by reading the report understanding the root cause,” Gibbs said.
To space Tweeps, Twitter is so much more than just a news service. It’s a community, a spot where everyone can showcase their interests and form professional bonds with each other.
The most prominent space-themed Twitter accounts of 2012 somehow transcended their original purpose, too. A NASA Mars Curiosity account ended up hobnobbing with comedian Steve Martin, and a space-station-passing service suddenly found itself in bit of a Twitter controversy.
Here are 10 of some of the most memorable Twitter accounts from this year. Yes, there’s a lot of Mars reflected here, but the entities quoted below explore all over the Universe.
@astro_andre
Dutch astronaut André Kuipers spent the first half of 2012 orbiting Earth. From his perch aboard the International Space Station, he participated in the historic SpaceX docking in May and finished 50 experiments. But rather than dwell on these achievements, he spent his tweeting time in space showing his gorgeous pictures of Earth. Maybe that old Apollo phrase about going to space and discovering Earth still has resonance today.
@BadAstronomer
Phil Plait is a good scientist-cum-journalist to follow in general, because his tweets constantly show his love of the universe. (“Embiggen!” he would perhaps shout at this point.) What made him stand out in 2012, though, was his willingness to use his immense Internet fame to showcase the work of others, such as his frequent Tweeting and posting of great space images and timelapse videos, or helping to ‘kickstart’ new projects and help them get off the ground, such as the Uwingu astronomy startup. He shows that Twitter most definitely has altruistic use.
@chrislintott
Chris Lintott demonstrated how to handle a situation when a close, beloved colleague passes away. The co-presenter of The Sky At Night was among the first official voices giving word of Sir Patrick Moore‘s death, and he retweeted messages of remembrance from colleagues and ordinary people. Nicely done, during what was a difficult time.
@claratma
Hard to believe Clara Ma is a mere 15 years old when reading tweets like this. The Kansas-based teenager named the Mars Curiosity rover. This year, she has been graciously fielding interview requests from journalists, and messages of support from NASA employees, ever since the rover made it to Mars in August.
@Cmdr_Hadfield
OK, I’ll admit my bias here: I’m Canadian. I’ve been watching Canadian astronaut Chris Hadfield since he was selected 20 years ago. But in the Twittersphere, he’s made an impact. My fellow journalists publicly speak about his work, with respect. His tweets showing his astronaut training are favourited and retweeted by people all over the world. And as the first Canadian to command the International Space Station next year, Hadfield will be a force to watch in 2013.
@MarsCuriosity
Three NASA employees are behind the “hive mind” of @MarsCuriosity. The official feed for the Curiosity mission skyrocketed to fame in 2012, receiving tweets from celebrities ranging from Britney Spears to the aforementioned Steve Martin. In this case, happily, “official” doesn’t always mean “staid.” The Twitter account has been a bevy of jokes and cheerful updates in between the standard scientific results.
@NASAVoyager
At 35 years and counting, the two NASA Voyager spacecraft have ventured into the newer field of social media. The accounts received more attention as Voyager 1 reached the edge of our solar system in 2012. It’s hard to summarize solar and interstellar physics in just 140 characters, but this official NASA account does it quite well.
@SarcasticRover
Nothing says pop culture as seeing your catchphrase — “Let’s Do a Science!” — repeated ad nauseum by planetary scientists on Twitter. The brainchild of Jason Filiatrault, this account is a parody of the official Mars Curiosity Twitter and depicts a rover angrily making its way around Mars after being ordered there by unfeeling humans. Besides wry observations of Martian life, the rover broadcasts its point of view on recent discoveries in a unique way.
@SpaceX
Not often that a corporate account uses four exclamation marks in a row, but the space geeks would argue this is justified. SpaceX made headlines and history in 2012 when the Dragon spacecraft berthed with the International Space Station — a first for a private spacecraft. SpaceX’s Twitter not only broadcasts mission news, but also seeks out mentions of the company and adds commentary.
@twisst
Just before the International Space Station passes by overhead, @twisst gives you a heads-up that you’ll be able to see it. This popular account’s service was briefly shut down in 2012 due to Twitter’s concerns about the duplicate accounts required to make the service work. But a few tweaks later, @twisst returned — to the delight of its thousands of followers.
