APOD: Curiosity Before Mars: Seven Minutes... (2012 Jul 31)

[APOD Robot]

Curiosity Before Mars: Seven Minutes of Terror

Explanation: Next week at this time, there may be an amazing new robotic explorer on Mars. Or there may be a new pile of junk. It all likely depends on many things going correctly in the minutes after the Mars Science Laboratory mission arrives at Mars and attempts to deploy the Curiosity rover from orbit. Arguably the most sophisticated landing yet attempted on the red planet, consecutive precision events will involve a heat shield, a parachute, several rocket maneuvers, and the automatic operation of an unusual device called a Sky Crane. These "Seven Minutes of Terror" -- depicted in the above dramatic video -- will begin on Monday, August 6 at about 5:24 am Universal time, which occurs on Sunday night, August 5 for western North Americans. If successful, the car-sized Curiosity rover will rest on the surface of Mars, soon to begin exploring Gale Crater to better determine the habitability of this seemingly barren world to life -- past, present, and future. Although multiple media outlets may cover this event, one way to watch these landing events unfold is on the NASA channel live on the web.

<< Previous APOD

This Day in APOD

Next APOD >>

[/b]

[Bert (NL)]

Sunday is 5 Aug, Monday is 6 Aug...

[ta152h0]

Caramba, vai ser muito bacana ! and I will eat all my vegetables for a month if you guys pull this off....

[Enginerrrrrrrrr]

Bert is right, the 5th is Sunday and the 6th is Monday. Either way I am ready to hear the exciting news on the landing! I am sure it will go off without a hitch

[hhm]

Please don't use AM and PM with Universal time.

[Ann]

This landing is going to be incredibly complicated. Surely past Mars landings have, for the most part, not been this "choreographed"?

Is this multi-step landing sequence an experiment and a detour from a simpler, more "normal" landing?

Does this complicated landing have any bearing on future manned missions to Mars? How hard will it be for future astronauts to land on Mars and survive the landing procedure?

Ann

[johnlbee]

There is some excellent information about the Curiosity mission and landing here:
http://www.jpl.nasa.gov/news/press_kits/MSLLanding.pdf and http://www.nasa.gov/mission_pages/msl/index.html

From the NASA press kit:

Two live feeds of video during key landing activities from mission control rooms at JPL will be carried on NASA TV and on http://www.ustream.tv between 8:30 and 11:00 p.m. PDT on Aug. 5 (11:30 p.m. Aug. 5 to 2:00 a.m. Aug. 6 EDT), and between 12:30 and 1:30 a.m. PDT on Aug. 6 (3:30 to 4:30 a.m. EDT). The NASA TV Public Channel and http://www.ustream.tv/nasajpl will carry a feed including commentary and interviews. The NASA TV Media Channel and http://www.ustream.tv/nasajpl2 will carry an uninterrupted, clean feed.

I am not sure what time this equates to in any one part of the world (or if the landing information from press kit is even the most current). Good luck staying tuned to the mission and robotic fingers crossed for the landing.

[inertnet]

This might help in translating UTC into your local time:

http://earthsky.org/astronomy-essentials/universal-time

[ronplu40@yahoo.com]

The 7 minute video was very cool. Good luck with the landing.
Ron

[nstahl]

Good luck indeed! I do think the term "from orbit" is seriously misleading. It will never be in orbit, it will be slamming into Mars's atmosphere and hopefully not into Mars. So "from space" would be an improvement.

[neufer]

Next week at this time, there may be an amazing new robotic explorer on Mars. Or there may be a new pile of junk.

[Indigo_Sunrise]

Sunday is 5 Aug, Monday is 6 Aug...

Bert is right, the 5th is Sunday and the 6th is Monday. Either way I am ready to hear the exciting news on the landing! I am sure it will go off without a hitch

It should be Sunday/Monday, according to this link.

Very cool!

[neufer]

Sunday is 5 Aug, Monday is 6 Aug...

Bert is right, the 5th is Sunday and the 6th is Monday. Either way I am ready to hear the exciting news on the landing! I am sure it will go off without a hitch

It should be Sunday/Monday, according to this link.

If it crashes just because they used the wrong calendar....

[petermauro]

This may be a stupid question: Why don't they use the previous landing technique:
A big balloon.

[neufer]

This may be a stupid question: Why don't they use the previous landing technique:
A big balloon.

There are no stupid question, just stupid answers; e.g.,

[b][color=#0000FF]NASA engineers test the Mars Pathfinder airbag landing system on simulated Martian terrain[/color][/b]

---

<<The first use of airbags for landing were Luna 9 and Luna 13, which landed on the Moon in 1966 and returned panoramic images. The Mars Pathfinder lander employed an innovative airbag landing system, supplemented with aerobraking, parachute, and solid rocket landing thrusters. This prototype successfully tested the concept, and the two Mars Exploration Rover Mission landers employed similar landing systems. The Beagle 2 Mars lander also tried to use airbags for landing, but the landing was unsuccessful for reasons which are not entirely known. Landing a large mass on Mars is a difficult challenge. The atmosphere is thick enough to prevent rockets being used to provide significant deceleration, as flying into the plume at supersonic speed is notoriously unstable. Also, the atmosphere is too thin for parachutes and aerobraking alone to be effective. Although some previous missions have used airbags to cushion the shock of landing, the MSL [at 5 times the mass of Spirit or Opportunity] is too large for this to be an option.>>

Galileo Says Size Matters. Elephants and Jell-o Agree.
By Ryan | Published: September 2, 2010

<<In 1638 Galileo Galilei published the Square-Cube Law. Frankly, it’s not particularly clever as scientific discoveries go. It’s an observation that big things are bigger than small things. However, the particular way in which objects scale does create a few interesting implications. I’m going to explain the concept using Jell-o. Alright, so imagine a perfect cube of that fruity lime-flavoured gelatin dessert sitting on a plate. Let’s say the cube is 1 inch in all directions. But, seeing as how there’s always room for Jell-o, you say you want “twice as much”. So, you would be expecting a cube that is two inches tall. Twice as much, right?

Not so! It may be twice as tall, and twice as wide, but the other measurements of size have more than doubled. The surface area has been squared, and the volume has been cubed. (hence Square-Cube Law) So, going by the volume, you actually have eight times more Jell-o in a 2-inch-sized serving as you do in a 1-inch-sized serving. A serving 4 inches across would contain 64 times as much Jell-o! This exponential growth puts a hard limit on how big your Jell-o serving can get before it overwhelms the structural integrity of gelatin. As the volume increases, so does the weight of all that Jell-o pushing down on the bottom-most layer. (the mass is growing faster than the footprint, so the pressure increases) If you visualize this growing cube on your dinner table, you can picture it begin to bulge and eventually crush itself into a gooey mess.

This same law puts a limit on the size of land animals. It explains why ants can walk around on spindly little legs while lifting 50 times their body weight, compared to elephants with their tree-trunk sized feet who would strain to lift a quarter of their mass. It also affects more than the size of animals. Elephants are practically naked (compared to most other fuzzy-haired mammals) because they have significantly more inside (volume) relative to their outside (surface area) and have a much harder time cooling down their body temperatures. Maximizing the surface area for cooling also explains the big floppy ears and wrinkly skin, which can expel more heat than a smooth surface. It also explains why the Nazis failed when trying to build a massive tank, and why our giant friend Robert Wadlow needed leg braces to walk. Oh, and why an elephant might die if it could only jump, while a mouse could safely fall off a building. And lastly, if not to beat a dead horse, it explains why Goliath probably wasn’t ten feet tall.>>

[petermauro]

Thanks, good explanation

[FloridaMike]

If it crashes just because they used the wrong calendar....

Hopefully, no metric calendars have been used in the planning of THIS mission.

[richard schumacher]

Very professional looking. Where is the video that shows an engineering test article dropping away from a parachute, hovering on rocket power, and winching a rover to the ground?

Putting the rover under a dust cover for a propulsive landing would have been more reliable.

[johnlbee]

This may be a stupid question: Why don't they use the previous landing technique:
A big balloon.

When it hits the top of Mars atmosphere the craft will be travelling 13,200 mph. 7 minutes later 900 kg of rover will be at standstill on the surface (in one piece or very many). I guess for the weight of the craft balloon landing would not be feasible.

[orin stepanek]

Hopefully; come Monday, we can say: 'job well done'!

[RJN]

Sunday is 5 Aug, Monday is 6 Aug...

Yes. Oops. Fixed. Thanks! - RJN

[Keyman]

Wow. Just...wow!

[Jim Leff]

This landing is going to be incredibly complicated. Surely past Mars landings have, for the most part, not been this "choreographed"?
Is this multi-step landing sequence an experiment and a detour from a simpler, more "normal" landing?

The previous rovers, Spirit and Intrepid, were "bounced" onto the surface in protective airbags. That won't work for Curiosity because it's much bigger/heavier (in order to accommodate the instruments necessary to help solve many new questions raised by the previous rovers' experiments).

The bouncing wasn't exactly "normal", either. The problem is that the Martian atmosphere is too thin to do a thorough braking job, so we need to get creative in how we land spacecraft coming in at over 12,000 mph.

Does this complicated landing have any bearing on future manned missions to Mars? How hard will it be for future astronauts to land on Mars and survive the landing procedure?

A huge issue is the 15 minute signal delay from Mars, which requires unmanned spacecraft to be completely self-sufficient in these tricky landings. With human pilots making real-time adjustments, there would presumably be much more flexibility and less need for contrived Rube Goldbergian mechanisms. As-is, we're stuck, as nstahl says, with "slamming it into Mars's atmosphere and hopefully not into Mars."

[Ann]

Thanks for that fine explanation, Jim!

Ann

[rstevenson]

I'm curious as to why they didn't use aerobraking for this mission. Yes, it can take a while, perhaps six months of repeated passes, but it would greatly slow the craft and result in, I assume, a gentler approach to landing.

Rob