A marvelous, mini-cooper sized mobile laboratory named Curiosity is on its way to our closest neighbor in the solar system! Launched on Friday, November 25, this is the largest rover yet to make its way to the surface of Mars. At a weight of one ton, it is about five times bigger than the very successful Spirit and Opportunity Mars Exploration Rovers that landed on the Martian Surface in 2004.
The differences do not end at size, though. When Curiosity lands in early August 2012, it will do so in a way entirely different from the “airbag” method deployed in 2004. Rather than bounce and tumble to a stop, Curiosity’s lander will deploy and discard the usual heat shield and parachute, and then will lower the mobile unit gently to the ground via a reverse-thrusting Sky Crane, which will then detach and fly away to a crash landing.
Also, given the large size of the rover and the complex instrumentation on board, Curiosity cannot simply rely upon the solar panel “wings” that were employed in the 2004 Mars Exploration Rovers. Curiosity will be packing a Plutonium-fueled Multi-Mission Radioisotope Thermoelectric Generator. The power supplied by the 32 marshmallow-sized pellets of Plutonium will power two on-board computers as well as mass spectrometers, gas chromatographs, spectrometers, and a series of mobility and safety systems.
As it roams around the Gale Crater, the mission of the Mars Science Laboratory is deeply embedded in the collective science fiction imagination: habitability of the planet’s surface. By studying climate, weather, mineralogy, and searching for bio-signatures of possible former Martian life, the Rover’s findings will be part of planning for a human mission to Mars.
So while the high technology on board (including the sky crane and a big honking infrared LASER) is certainly thrilling, the more exciting prospects revolve around how we will send ourselves. As with all rover missions, the rover carries signatures including that of the President, Clara Ma, the fourteen-year-old girl who won the contest to name the rover two years ago, and the millions of micro-signatures from NASA fans who signed up online.
Think you’ve got the right stuff for a human mission to Mars? Why not apply for the Astronaut Candidate program (science teachers welcome), but hurry, since applications close shortly after the new year.
Read about the design process for the Mars Science Laboratory here.
Where my lady cosmonauts at? “…men should lead the way to distant planets and carry women there in their strong hands.” ?!?!? ‘Scuse me?
Dear Ms. Wortel,
I’m writing to you concerning your 2007 article in the American Journal of Physics (with Malin and Semon) titled “Two examples of circular motion for introductory courses in relativity.” I am particularly interested in Section VI on Thomas precession. In that section, you state: “It is important to remember that Thomas rotation and Thomas precession are observed by the traveling twin and not by the Earth twin…” Most other authors say just the opposite! I would like to submit that both views are right, depending on the perspective. To explain, consider the simplest explanation of Thomas precession ascribed to the late E.M. Purcell, in which an observer (the “traveler”) travels around a regular polygon of N sides, i.e., an N-gon. Purcell’s approach is described in the appendix to Richard Muller’s “Thomas precession: Where is the torque?” in AJP, vol. 60 (4), 1992, pp. 313-317. In this approach, Lorentz contraction of the “straight-ahead” component of the next leg of the N-gon requires the traveler to turn not through an angle of (2pi)/N, but through (2pi)*gamma/N, where gamma is 1/(1 – v^2/c^2)^1/2 and is always greater than 1. The scenario involves an “inertial bar” which points along the direction of travel along the starting leg of the N-gon. The properties of this inertial bar are such that when the traveler turns through an angle, the bar’s orientation changes with respect to the traveler by this angle. True, when the traveler turns through an angle of 2pi, its direction of travel is again aligned with the direction of the bar, and only in this sense is Thomas precession not observed by the traveler. But it takes an angle of 2pi*gamma for the traveler to get back to the starting point, because N turns, each of 2pi*gamma/N, must be made. When this point in the trip is reached, the traveler is back at the starting point, and in this sense the rod is not aligned with the direction of travel. Indeed, the rod is angled at precisely the value given by Thomas precession, i.e., the traveler does observe it, as does the laboratory (or stay-at-home) observer.
I found Muller’s article most fascinating, especially his explanation of how a real physical torque causes the precession for a gyroscope. But he says nothing about torque on the inertial bar, and I will query him on it.
I would be interested in your response. I will e-mail the above remarks to Drs. Malin and Semon also.
Sincerely yours,
Frank Munley
Associate Prof. emeritus, Roanoke College
Ms. Wortel,
My apologies–I overlooked the fact that your paper uses Purcell’s argument. But I still believe your conclusion is wrong about the absence of Thomas precession in the lab frame. I should add that I am writing to you on your blog because I don’t have an e-mail address for you. And I have written to Drs. Malin and Semon concerning my question. One final note: I enjoyed reading your blog above on “Curiosity.”
–Frank Munley