WASHINGTON – On Aug. 5, 2012, after completing a nine-month, 354 million mile journey, mission controllers at NASA’s Jet Propulsion Laboratory will attempt to break the fall of a rover-carrying spacecraft traveling at about 13,000 miles per hour to zero and set down the rover in a Martian crater.
The landing sequence for the Mars rover Curiosity is called the “Seven Minutes of Terror.”
For the first time, NASA will use an untried descent and landing technique to lower Curiosity to the surface near Gale Crater using a sky crane. The entire landing sequence will be controlled by computers relying about 500,000 lines of code that will control no less than 76 rockets and thrusters.Mission managers won’t know whether it worked for 14 minutes, the time it takes a signal from Mars to travel back to Earth.
To the casual observer, using a sky crane to land on Mars may look crazy, but “it is the result of reasoned engineering thought,” argues JPL’s Adam Steltzner, chief engineer for the Mars Science Laboratory.
“If any one thing doesn’t work just right, it’s game over,” adds JPL’s Tom Rivellini.
Previous Martian landings used what amounted to air bags to break the fall of rovers. Curiosity is too big and heavy – about the size of an SUV – to use that landing method. Hence, JPL engineers came up with a system of braking rockets, a huge parachute and the sky crane to slow Curiosity’s fiery entry into the faint Martian atmosphere and gently deposit it in Gale Crater, which is suspected of harboring signs of Martian life.
The JPL engineers and scientists are sticking their necks way out on this mission, and that’s precisely the type of technological risk-taking that is needed to explore the solar system with our marvelous machines.
My guess is that the first manned mission to Mars will be a one-way trip. We simply lack the propulsion technology to break out of the Martian "gravity well" and return home. This is controversial, but probably the only way humans will get to the Red Planet until we figure out a better form of propulsion that doesn't require dragging along millions of tons of fuel for the return flight.
I think the simple answer is that Mars is much farther from Earth than the moon. The Apollo landings had the advantage of Houston being able to monitor telemetry, critical LM systems and fuel consumption in near-real time. Due to the distance and comms delays, a Mars landing must be autonomous, and hopefully the system is designed to interpret onboard radar and adjust the flight profile "on the fly."
*Not singling out DrQuine - this is a generic statement*
One thing I've learned over the years; when it comes to large design and engineering programs like this, I assume anything I may have "thought" of, so did they, and got there much faster than I would have. As with any endeavor, or simply our day to day jobs, when you have your nose in it 24/7 you see things others around you couldn't if they wanted to. I'm all for design reviews; they are a vital part of the engineering practice. But doesn't it burn your behind when someone asks "Did you think of xxx"? In your head your saying "Yes, and for xxx reasons I abandoned that idea. If you were as focused on this as I am you would not have asked that question". This is not to say I work in a bubble, or don't value others thoughts and ideas. Just the opposite; I think I'm pretty good at what I do, evaluate all reasonable options before coming to a decision. If I get "stuck" I'll ask for input. Certainly there is no way JPL could have explained every aspect of every decision they made in a short video (or even a video 30 hours long). Given the resources available to them (I'd love to have 1% of the computing power available to them for FEA) I have to imagine they've examined every past mission that we know about (and those we don't) to come to the decisions they did.
I understand the desire to get larger rovers to the surface, but if this requires controlled descent, rather than ballistic descent, then wouldn't it be prudent to first achieve some mundane infrastructure missions? Instrumentation and comms satellites have been sent, but why not a Mars global positioning system? I would think that would greatly simplify navigation, both for the entry vehicle and for the rover, as well as provide precise location of any interesting discoveries. Its cost would be amortized across many missions for decades.
One simple question was never addressed in this extraordinary story and challenge that is certainly attracting a record breaking volume of commentary. Why not build upon the manned lunar landing technology with a radar equipped control rather than a human pilot? Seems like a much lower risk solution for a comparable payload weight (the lunar lander weighed 16 tons but the moon has a lower gravitational force).
This is the most complicated automated high-reliability project I've ever heard of. I think it's great, and I wish them complete success.
This is why we shouldn't waste money on manned missions. In order to get a big science package to Mars, they're doing something incredibly risky.
If humans were sent, the whole project would be about keeping them alive. The project would take forever, and in the end, there'd be no room left over for actual science.
Space technology works because it is an assembly of simple components or other simple assemblies. Each assembly step is examined to ensure it does not create additional complexity in its components or other assemblies (loose coupling, encapsulation). Components are based on known provable or reliably simulated principles (= reusing prior art). Interfaces are designed and reused consistently, so that the parent design can be exhaustively tested and the benefits inherited by the child applications.
Can we learn from this? It _is_ rocket science, but it is mostly not complicated in the sense of magic, impenetrable black boxes.
On the other hand, a lot of the math IS complicated, in the flight vectors and even the reliability engineering statistics.
There are metric units, and there are obsolete units.
I was slightly perturbed to hear the parachute engineer still referring to "pounds-force".
I'm English, and we don't use "English" units, so why does anyone else?
If we take a look at Space-X and at this mission, we can see what I see as the future of space leadership for this country: Private industry refining orbital work into just another commercial business and NASA exploring, inventing and pushing the envelope.
David Patterson, known for his pioneering research that led to RAID, clusters and more, is part of a team at UC Berkeley that recently made its RISC-V processor architecture an open source hardware offering. We talk with Patterson and one of his colleagues behind the effort about the opportunities they see, what new kinds of designs they hope to enable and what it means for today’s commercial processor giants such as Intel, ARM and Imagination Technologies.