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Time to Head for Mars?
NASA's Phoenix Mars probe touched down this weekend on the 47th anniversary of JFK’s "man on the moon" address to Congress. What will this mission mean for the future of human spaceflight initiatives?
Are we alone?
That has been one of the fundamental questions about the universe since humankind first realized that we live on only one planet in its vastness. And of course, the first places to look for the answer are the nearest planets that have any prospects for supporting life at all, since that’s a requisite condition for finding intelligent life. Hence the long fascination with Mars.
The latest robot emissary sent to resolve the old issue descended to the surface of the red planet on Sunday evening (US time). The descent was first violent, as it crashed into the thin, dry Martian atmosphere at a velocity sufficient to escape the planet’s gravity, and then gentle, with parachutes and rockets. It was a new spacecraft design, with a mission derived from two previous Martian mission failures.
One was the Mars Polar Lander, with which contact was mysteriously lost just before it was to enter the Martian atmosphere in 1999 on its way to the south Martian pole. Its companion explorer was the Mars Climate Orbiter, which was supposed to brush the top of the Martian atmosphere to slow it down into an orbit around the planet, whence it was to relay data from the lander back to earth while also monitoring the planet from a polar perspective at a constant sun angle. Instead, it flew into the atmosphere at a steep angle, destroying the spacecraft almost instantly from the rapid deceleration and heating for which it was not designed. Ignominiously, this was a result of confusion between metric and English units between NASA and its contractor.
The new spacecraft was designated Phoenix, as a symbol of its arising from those failures. Like another Greek myth, it is a hybrid of two spacecraft — a lander from a mission canceled after the MPL/MCO failures, and backup versions of many of the same instruments carried by MPL before its loss. It is now set to carry out their intended mission and — for the first time — explore the polar regions of the planet close up. However, while MPL was aimed at the southern hemisphere, Phoenix has landed on the plains of the Martian arctic regions, in the far north. But both polar regions are now known to have large quantities of water in the form of ice, so either will serve the purpose of the present mission, which is to determine if in the past there was water in liquid form, long thought to be required for life to develop and thrive.
Interestingly, it was the first “soft landing” on Mars in over three decades. The last time that NASA used retrorockets to perform final landing maneuvers on Mars was also the first — in the Viking program in 1976. The Mars Pathfinder and later rovers came hurtling down in a bouncing ball that gradually took away the energy of the fall, but such a scheme wouldn’t necessarily scale up well for a craft the size of Phoenix, which was anyway designed before the technique was proven. And landing gently is good practice for when we eventually send humans, who won’t take well to the bone-crushing and vertigo-inducing accelerations of a long superball ride absent major steps toward body modification.
The lander will carry a robotic arm with an ice pick, to chip away samples of the frozen soil. It also has a portable oven and laboratory to examine them for evidence of not just ice, but perhaps microbes, or at least organic chemicals which would be precursors for life, if that life is anything like we understand it on earth. It will have about three months to do so, before the Martian boreal winter sets in and the craft gets buried under ice, mostly dry ice, as the atmosphere itself (mostly carbon dioxide) freezes and solidifies around it. At this point the vehicle will be dead because its solar panels will be covered and unable to produce electricity, and it has only a twenty-four hour battery, which will drain over the winter to the point that it will be unable to “wake up” if and when the ice melts or sublimates. For those three months, unlike the popular Mars rovers, it will perform its experiments in a single location, lacking the ability to transport itself elsewhere. So, as is always the case, a failure to detect such signs won’t be indicative of their absence. It may have just been unlucky in landing spots. Mars is smaller than earth, but it is a very big planet nonetheless, and it’s all land and no sea. If life signs are scarce, the search for them may remain elusive, even with hundreds of probes. After all, how likely would it be to find a dinosaur fossil if the search was based on simply throwing a dart at a map, even of western Colorado?
This mission, like all Mars missions, is not just to answer pure science questions. It is also ostensibly a precursor to eventual human trips to Mars. The discovery that water is available in large quantities at the poles was encouraging to those who plan to “live off the land” there. But perhaps those who hope to one day be Martians themselves should also hope that Phoenix doesn’t find signs of life, at least current life. If it does, it’s not at all inconceivable that the planet would be put under quarantine from humanity so that we don’t contaminate it with our own life forms (this is a concern even for the robotic envoys, such as Phoenix, to the point that they are scrupulously sterilized prior to launch). Beyond that, for reasons having nothing to do with Mars, some say that we should hope that we are alone because to learn otherwise might be a bad omen for the human race.
In any event, given the current budgetary, schedule and technical difficulties of NASA’s new manned spacecraft programs, Ares and Orion, and the uncertainty of the political support for them in the next administration, such a mission seems very far off right now. The Phoenix landed on the forty-seventh anniversary of JFK’s speech to Congress in which he declared a national goal of sending a man to the moon in that decade. George W. Bush made a similar announcement a little over four years ago, in which Mars was designated a destination for human explorers, but only in passing as part of (in reference to returning to the moon) “…and beyond.” So congratulations to JPL, but unless Phoenix finds Marvin, with plans for interplanetary conquest, including earth-shattering kabooms, don’t expect its successful landing to result in any new presidential speeches on human spaceflight initiatives.
Rand Simberg is a recovering aerospace engineer and a consultant in space commercialization, space tourism and Internet security. He offers occasionally biting commentary about infinity and beyond at his weblog, Transterrestrial Musings.
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16 Comments
1. Benson:Clarification requested. Isn’t the magnetic field of Mars so weak that a stay of just a few days would be dangerous?
How do the lunar and Martian environments compare, as regards the solar wind? Does the fact that people have been on the moon imply it’s safe to spend time on Mars? What little I could understand of the information I found tells me that the moon has some variable magnetic protection from the solar wind, but I could not come to any conclusion that helped me understand the Martian situation.
Too, I don’t understand the mention of escape velocity regarding the approach of the lander to the planet. Yes, the craft was going very fast and had to slow down, but…. ?? Isn’t the significance of escape velocity entirely a matter of trajectory, that is, of intent?
May 27, 2008 - 6:39 am 2. Concerned Citizen:Why waste the money sending people to Mars when you can establish a Lunar mining outpost for the same cost.
The moon is closer and there are useful minerals that can be mined, then shipped back to Earth. At least there is some chance for an economic return from this kind of mission. A trip to Mars is one big financial black hole for limited benefit.
If you’re searching for alien life, save the billions of $$ and go look in Area 51.
May 27, 2008 - 7:09 am 3. Ten:Given the trainwreck the US government has made of the US economy, I question NASA. I have a habit of questioning monopolies, collectives, state agencies, bureaucracies, and government itself.
So. What’s all this rubbish about a statist operation to somehow establish “outposts” in hard vacuum hundreds and hundreds of thousands of miles away for the obvious purpose of spending money we don’t have? (But could print!)
My vote? Close down NASA, yet another of the colossal, egotistical wastes of money devised by a bankrupt federal government — NASA was devised to beat the Soviets in a useless race for bragging rights. NASA is therefore obsolete.
Either that or have it prove profitability. Surely “shipping minerals back to Earth” can be made profitable, no?
May 27, 2008 - 7:16 am 4. Brett Bellmore:“Isn’t the significance of escape velocity entirely a matter of trajectory, that is, of intent?”
Not unless you’re planning on missing the planet. The escape velocity represents the lowest velocity you’d arrive at a planetary surface from a great distance, if you didn’t do any braking. Varying the trajectory can only result in additional increments of velocity, particularly in the case of Mars, which lacks satellites large enough to be useful for gravity well maneuvers.
May 27, 2008 - 7:18 am 5. Benson:I wish I understood your response, Brett, so I should shut up. But — I’d like to try one more time. If I’m leaving Mars, I do have to exceed escape velocity. But if the trajectory is exactly the opposite, meaning my intent is to arrive rather than take off, then my concern is to brake to a slow enough speed so the impact is tolerable. I ignore escape velocity, and merely adjust braking power as needed, so I reach zero velocity on touchdown. But because the robot lander can’t fine-tune its braking power as it descends, and because escape velocity is an expression of gravitational attraction, escape velocity must be taken into account when programming the landing. Have I got it now?
May 27, 2008 - 9:00 am 6. The Daily Links « The Four Part Land:[...] Time to Head for Mars? – What does the Phoenix offer to human spaceflight? [...]
May 27, 2008 - 10:00 am 7. Joe:Brenson, what goes up must come down. And it comes down just as fast as it went up. It works the same way even if the object never went up first.
A object falling from a long distance is going the same speed down as it would have to be going in the opposite direction to get up. The the phrase escape velocity tell you how fast you will be going when approaching a planetary body from a great distance.
Now it is possible to approach a planetary body at a speed greater than escape velocity, how because it is so difficult to make a object to go at great velocities, with rockets. It isn’t going to be happening in any normal planetary probe encounter.
May 27, 2008 - 10:53 am 8. Rand Simberg:Sorry for the confusion. I was simply trying to convey how fast the probe was approaching (which is Mars escape velocity, for the reasons that Joe states). Technically, of course, it was only escape *speed* (scalar), not escape velocity (which is a vector), because escape velocity would require a vector pointing in some direction that didn’t impact the planet or its atmosphere…
May 27, 2008 - 2:00 pm 9. Benson:Boy, it IS time for me to shut up!! There is so much here that makes no sense to me at all…. Never mind what offends and confuses me about these explanations; assuming I’m an average college graduate, I’d say this suggests that the education of the average person is dismally deficient in basic science, eh? That can’t be good. My ignorance is not just something I’m ashamed of — it concerns me that many others may be just as clueless as I am (but don’t feel comfortable admitting it)!
May 28, 2008 - 4:05 am 10. IcePilot:Mars is the ultimate dead end. The human race isn’t getting into space until someone figures out how to make a buck up there (other than communications satellites). Ask yourself this question – What will be produced on Mars and sold for a profit on Earth? We need to get away from the idea that we need to go to a PLACE, like Mars or the Moon, and understand that once you get into space, you are there! Unlimited, free solar energy, 24 hrs a day; unlimited resources in the earth-crossing asteroids and no gravity (90% of the Golden Gate bridge serves no purpose other than to counteract gravity). We can build structures, factories and whole industries that will turn our 3 trillion dollar economy into a 30 or 300 trillion dollar economy. That’s what it will take to convert third-world countries into efficient, 21st century societies. Read G.K. O’Neill on solar power satellites and J.S. Lewis on “Mining the Sky”. To get a pound into high Earth orbit (delta-v = 10 km/s) costs NASA $10K. Starting from there, the round trip delta-v to: Mars=10.5 km/s, Moon=4.7 km/s, asteroid 1982DB=0.12 km/s.
Do the math.
Although I will concede that the Helium-3 on the Moon is worth going after. It’s the perfect fusion fuel.
May 28, 2008 - 8:33 pm 11. IcePilot:For info on how to get off this planet: http://www.permanent.com/index.htm.
May 28, 2008 - 8:47 pm 12. DWMF:Also, the book “Moonrush, Improving Life on Earth w/the Moon’s Resources”, by Dennis Wingo, lays out how to get back to the Moon (in a permanent way) for less than 5 billion dollars – a tenth of what it will cost NASA.
IcePilot said: Ask yourself this question – What will be produced on Mars and sold for a profit on Earth?
OK. Not specifically Mars – but mining metals in the asteroid belt. A station on the North Pole of Mars would be a good base of operations – or maybe a space station in Mars orbit.
I fancy a series of probes exploring the asteroid belt, called Prospector.
May 29, 2008 - 4:17 am 13. chefgodzilla:Mars sounds great………..for liberals. It’s dark, cold, and desolate – just how they want the rest of us to be.
May 30, 2008 - 6:46 am 14. Fat Jolly Penguin:“Clarification requested. Isn’t the magnetic field of Mars so weak that a stay of just a few days would be dangerous?
Mars doesn’t have a magnetic field, but differing patterns of magnetic rock in its soil have shown that it did at one point. The solution to this is to develop some form of shielding system to protect the explorers; even what was used on the lunar missions wouldn’t be strong enough, since it didn’t entirely protect those astronauts from solar radiation.
Mars sounds great………..for liberals. It’s dark, cold, and desolate – just how they want the rest of us to be.
Ooh, you are evil. I like!
May 30, 2008 - 7:45 am 15. Pajamas Media » The Biggest ‘Non-Discovery’ On Mars in History:[...] they did that would be the biggest find in the history of space science to date). And as I’ve noted previously, prospective Martians currently living on earth should hope that they don’t, lest the planet [...]
Aug 2, 2008 - 6:49 am 16. Nikola:In the early seventies in one of the Moon misions an astronaut that was walking about on the moon’s surface shouted ¡Water!¡Water!.I remember that because it was clearly heard through the familiar radios set. Never more afterwars neither NASA nor the media said anything about that important fact. I sent a mail to NASA’s site inquiring about that event but they didn’t clear the case at all.
Aug 26, 2008 - 6:43 am