The Mars rovers Spirit and Opportunity are by far one the most successful mission we’ve ever had on another planet. Designed for a total mission time of only 90 days they have gone on to outlive that deadline numerous times over and if it weren’t for an insidious soil trap they’d both still be running today. Whilst Opportunity might still be running a good 7 years after it made planet fall that doesn’t mean that it’s capable of performing all the tasks we want to do and so NASA has been busy designing a replacement rover. It’s quite something to behold and it just recently hit a very important milestone.
The next rover’s official name (dubbed Curiosity in a contest to name it, much like its predecessors) is the Mars Science Laboratory and considering its payload that’s fairly apt. Compared to the Mars Exploration Rovers it’s quite the beast being 5 times more massive and carrying 10 times the scientific payload. To put that in perspective the MSL will be about the same size as the Mini Cooper, the MERs combined would only equal it in length. Such size does present some challenges for getting it down on Mars however, but the guys at NASA have devised a really ingenious way of making sure it arrives safely.
Many are familiar with the way that the MERs made their landing on Mars. They used a combination of aero-breaking (basically parachutes) combined with inflatable bags on the outside that allowed them to bounce over the surface until they landed safely. The MSL is just too heavy for that kind of landing to work so NASA has devised a multi-stage descent that utilizes aero-breaking, retrorockets and a crane system to drop it safely on the surface. I could try and explain it to you but its far more impressive to see in video:
Compared to the way the MERs landed this does seem like an extremely overcomplicated way of landing but given the constraints it’s the best option available. NASA is stepping into unknown territory here so until the landing is confirmed I can see everyone being on tenterhooks.
Keen observers would have noticed something different about the MSL when compared to its MER cousins, most notably the distinct lack of solar panels. The MSL gets all of its power from a radioisotope thermoelectric generator (RTG), the same device that’s powered Mars landers and the extremely long lived Voyager probes. These devices work by using the heat from radioactive decay of an element, usually enriched plutonium, and generating electricity via a thermocouple. The RTG on board Curiosity will generate around 125W of power when its launched, dropping to 100W only after 14 years in service. The mission time frame is slated for just under 2 earth years so the RTG is more than up to the job and there’s the tantalizing possibility that this particular rover could be working for a very long time to come.
The MSL’s payload is simply staggering so I won’t recreate it fully here but there are a few interesting pieces that I’d like to highlight. The first is the MastCam which is a high definition camera that will sit on top of Curosity’s mast. It’s able to take 1.92 megapixel images and 10fps 720p video in true colour, something that other rovers have had to fudge with their black and white cameras with colour filters. There’s also ChemCam which has an infrared laser capable of vaporizing rock at 7 meters then analysing the resulting plasma ball, which is just plain cool (lazers, IN SPACE!).
The milestone I was hinting at earlier was that the MSL has just been sealed up in its payload faring, ready for the trip to Mars:
With its launch window opening in less than two months, the Mars Science Laboratory was matched up with its heat shield at Kennedy Space Center’s Payload Hazardous Servicing Facility on Wednesday, Oct. 5.
The completed MSL rover, a.k.a. “Curiosity,” had already been fitted onto the “back shell powered descent vehicle” — a revolutionary landing mechanism that will first deploy parachutes to slow the capsule’s descent and then use rockets to hover above the Martian surface as it carefully lowers the one-ton rover down on cables before finally launching itself away to fall at a safe distance.
The launch is scheduled to happen between November 25th and December 18th this year with the rover reaching Mars sometime in August next year. After that it will begin its 1 martian year mission, which is just a hair under 700 earth days. With the rover being fitted into the fairing now it signals that NASA has quite a good shot at hitting that launch window, especially when they’re using the tried and true ATLAS V launch system.
Curiosity really is a testament to what NASA is capable of when they put their minds to it. Everything about the new rover is boundary pushing and I’m sure that much like its predecessors it’ll continue to serve NASA and humanity long after its initial mission is completed. It’s going to be agony waiting for the landing confirmation but we’ve got a year and a long trip through space before we have to start worrying about that.
Bar the shuttle there’s only been one mission in recent memory that has managed to capture the attention and imagination of nearly the entire world. That mission is the Mars Exploration Rovers, a pair of plucky little explorers that touched down on Mars almost 7 years ago today beginning a truly epic journey that lasted well past their expected lifetime. They also hold the crown of being conceived, built, launched and spending the better part of a decade on one of our closest neighbours in the universe in the time that it has taken Duke Nukem Forever to be developed. Their impact on the world and our understanding of the universe cannot be understated and it is with a sadden heart that I bring you this news today.
Even though they were, for all intents and purposes, identical twins Spirit always had the hardest time on our red sister. For the first couple years they were both chugging along quite well but in mid March 2006 Spirit’s front right wheel locked up and failed to respond. This meant that for most of its life Spirit was driving around backwards, dragging the dead wheel behind it. It was both a blessing and a curse to the little rover as the dragging meant it could image the crevices it was leaving behind, providing some insight that we weren’t expecting. There was a brief moment of excitement when the wheel began to respond again, but it soon stopped responding shortly after. The rear right wheel also suffered a similar fate several years later.
Then in 2009 Spirit became stuck in a soft patch of Mars soil. At the time it didn’t seem like a big of a deal, they’d been in similar situations before with both rovers and managed to free them successfully, but this one presented some major challenges. The soil was an insidious creation of mostly iron sulfate which has poor cohesion and is like quick sand to the rover’s wheels. NASA then spent 9 months testing various scenarios on earth in a desperate attempt to free the craft before the harsh martian winter before giving up and declaring Spirit a stationary research station.
With the rover stuck in the soil it was unable to orient its solar panels to a favourable angle in order to generate enough electricity to keep its components warm during Mars’ winter. This meant that once that time came it was likely that the rover’s electronics would be subjected to temperatures far below what it was designed to handle, likely killing it in the process. It’s the same problem that faced the Phoenix Lander and the unfortunate truth is that it didn’t survive the winter. Spirit went dark on March 22, 2010 and all attempts to contact it since then have been met silence. This means that the rover is no longer functioning, frozen in its final resting place.
Spirit may no longer be communicating with us but its mission lives on in its twin, Opportunity, and it’s future incarnation in the Mars Science Laboratory called Curiosity. There’s also the very real possibility that SpaceX will be launching a mission to Mars in the near future and that gives us the very real possibility that us humans could be meeting up with our robotic creations much sooner than we think. So while writing this article brought a tear to my eye I know that Spirit won’t be alone in the Martian soil for long and we’ll be seeing it again very soon.
So long Spirit.
You’d have to be under a rock for the past 6 years to not know of the great successes of the Mars rovers Spirit and Opportunity. Initially only designed for a maximum operation of 90 days they have shown what good engineering and a little bit of luck can do for you as they’ve been running almost non-stop since they landed. They haven’t been without their share of troubles however with both of them becoming stuck in Mars’ unusual terrain at one time or the other. More recently however Spirit has been stuck at a point called Troy, which basically amounts to a typical sand trap with a rock in the middle of it. Here’s a little background on the situation:
The rover drove into soft ground a couple of weeks ago, and when it tried to get out, its wheels slipped and it moved only a couple of inches.
The Spirit has been stuck before, and mission managers have been assiduously driving it around potential hazards. But they did not see the soft spot, which was hidden under a veneer of normal-looking soil.
“It is quite serious,” said John Callas, the project manager for the Spirit and the Opportunity, its twin rover on the other side of Mars.
Steven W. Squyres, the principal investigator of the rover mission, said the material looked like ferric sulfate salt, which had previously been encountered. “From a rover mobility standpoint, it is insidious stuff,” he said. “This stuff has very little cohesion. What this means is that it’s very tough for the rover wheels to get a grip on it.”
Following the rover’s situation over at the NASA Free Spirit website shows that this initial report was indeed true. They began extraction attempts well over a month ago and progress has been extremely slow. If you have a look at any of the pictures over at their site you’ll see why, it’s pretty much wheel deep on all sides bar one which means it has very little traction. Compounded with the fact that the wheels weren’t really designed with this kind of surface in mind (the wheels would’ve been a lot larger and wider if they tried to compensate for this kind of terrain) we’re in for a long an arduous extraction process. Opportunity took about 3 months to extract itself out of a lesser situation, and had all of its wheels working.
Still it seems that despite its difficult situation the rover team is making the best of it. The rovers don’t really spend much time in any one spot and they rarely get themselves into a situation where they’re digging more than an inch into the martian soil. As it turns out all this wheel spinning has managed to break through the thin top crust and liberate some of the deeper down soil, with some very interesting results:
Spirit broke through a dark reddish-brown crusty surface that was an inch or so thick, exposing loose, sandy material. As the rover tried to break free, its wheels began to churn the soil, uncovering even more sandy material, bearing “a higher concentration of sulfate that seen anywhere else on Mars,” Arvidson said.
“Sulfates are minerals just beneath the surface that shout to us that they were formed in steam vents or hydrothermal pools, since hot water associated with these systems has sulfur in it,” he explained. “These deposits are evidence of water-charged explosive volcanism. Such areas could have once supported life.”
“Also, the robot found that the top of the sulfate material is crusty,” Arvidson added. “Ancient sulfates probably formed this crust as they were processed by variations in climate associated with changes in Mars’ orbit over millions of years.”
That’s pretty exciting stuff right there and it just adds more credence to the theory that Mars was once a potential home to life and could quite possibly have been quite similar to our own blue marbel. It’s discoveries like these that have influenced projects such as the Mars Science Laboratory, which will answer these questions with much greater detail.
It’s not all bad news for Spirit however, they recently gave all wheels a diagnostic test to see what their condition was like. Although it was a long shot they decided to include the supposedly dead wheel a go as well, figuring that it was a long shot but could pay off big should it respond. To everyone’s surprise it did and whilst it’s not 100% conclusive that the wheel is ready, willing and able it does mean there’s a small glimmer of hope on the horizon for extracting Spirit out of Troy before it freezes to death in the martian winter.
Maybe we’ll see some traction (snicker) in the new year 🙂