[Space] NASA - Mars Exploration Rover MER-B "Opportunity" - Update Thread

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Opportunity Trajectory Adjusted for Mars Landing

16 January 2004

PASADENA, Calif. -- NASA's next robotic rover to attempt a landing on Mars -- Opportunity -- underwent a trajectory correction maneuver January 16.

Flight controllers here at the Jet Propulsion Laboratory (JPL) commanded the Opportunity spacecraft to finesse its path to more accurately enter Mars' atmosphere on Saturday, January 24.

Music played at misson control at JPL was "Carry On Wayward Son" by Kansas.

Opportunity is slated to drop onto Meridiani Planum, an area on Mars located on the opposite side of the planet from where Spirit is now parked.

As a twin to the Spirit Mars rover, Opportunity will land on January 24 about 9:05 pm Pacific Standard Time (PST).

The Trajectory Correction Maneuver more precisely aligned Opportunity for its dive toward the pre-picked landing point. Meridiani Planum is an intriguing locale on Mars where mineral deposits -- specifically hematite -- are suggestive that Mars had a wet past.

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Opportunity pre-landing press conference, ora su NASA TV!

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Opportunity Closes in on the Red Planet

By Leonard David
Senior Space Writer
posted: 04:00 pm ET
23 January 2004

PASADENA, Calif. -- Early Jan. 25, at about 12:05 a.m. EST, NASA's second Mars Exploration Rover -- Opportunity -- will arrive on Mars. It's headed for a region known as Meridiani Planum, halfway around the planet from where its sister robot, the Spirit rover now resides.

What Opportunity might find at that landing site could be the geological mother lode at Mars that scientists seek -- a type of mineral that cries out: "Water was here!" This site may well have been a suitable environment for microbial life.

PASADENA, Calif. -- Early Jan. 25, at about 12:05 a.m. EST, NASA's second Mars Exploration Rover -- Opportunity -- will arrive on Mars. It's headed for a region known as Meridiani Planum, halfway around the planet from where its sister robot, the Spirit rover now resides.

What Opportunity might find at that landing site could be the geological mother lode at Mars that scientists seek -- a type of mineral that cries out: "Water was here!" This site may well have been a suitable environment for microbial life.


Good dose of edginess

"I am almost as nervous as I was for Spirit," admitted Rob Manning, Mars Exploration Rover (MER) Entry, Descent and Landing Lead here at the Jet Propulsion Laboratory (JPL). "Even though Meridiani is an easier landing site in some respects…less winds, less slopes, and the rocks aren't as bad… I'm going to be almost as nervous," he told SPACE.com.

In reconstructing how Spirit made it down at Gusev Crater, Manning has reason to retain a good dose of edginess.

"We had a wild day in landing Spirit," Manning said. An unexpectedly large wind gust played havoc with the spacecraft's approach and touchdown at Gusev. That burst of wind pushed Spirit's parachute and other landing gear in a horizontal direction toward a crater.

An inertial measurement unit, computer software, special camera gear, and small rockets onboard Spirit worked in concert to counter what could have been a deadly drift into the walls of the crater -- "all within a handful of seconds," Manning noted.

"I don't know if we would have been toast. On the other hand, it's an experiment I don't think I would want to perform," Manning added.

Today, MER engineers at a press briefing here graphically demonstrated the close-call nature of flying 150 million miles (170 million kilometers) and screeching to a rocket-assisted airborne stop just 23 feet (7 meters) above Mars.

Once cut free from its parachute, retro-rocket engines, and long bridle, the set of airbags with the Spirit rover tucked inside fell onto the planet, bouncing 28 times across the martian landscape before coming to a full stop.

Using the Mars Global Surveyor orbiting Mars, Spirit's parachute, heat shield, airbag bounce marks, and the rover's stationary landing hardware have been imaged. The heat shield was found to have hit the side of the nearby crater that scientists want Spirit to hopefully visit -- reportedly now dubbed as "Bonneville".


Glue gun and duct tape

At the end of the day, Spirit's safe and sound landing comes down to one engineering rule of thumb: margin.

Margin equates to elbow room. There is a delicate balance between margins and how close-to-the-edge engineers feel is tolerable. But then add in the vagaries of the Mars environment, well, those uncertainties can give you a bad day.

"From what I see, we have a lot of margin. We are confident that we made the right design choices in our rover landing system to make it reliable," Manning said. "But you never know. If I could land a thousand of these things, then I could tell you. We're still in the infant stages of this stuff."

Lessons learned from getting Spirit down and dirty on Mars are being applied to the landing of Opportunity.

For example, Opportunity's parachute is to be deployed higher and five seconds earlier than planned over Meridiani Planum. Secondly, gas generators to inflate the airbag landing system have been tweaked to reduce their warm-up time during the plummet toward Mars' surface.

Opportunity's landing system is good to go, Manning said. "Our mission is not to do engineering, although it's fun, exciting, and a lot of work. It doesn't matter if you took a glue gun and duct tape to get to Mars. As long as you get there safely…and we get good science for the mission…that's the most important thing," he explained.


Colorful territory

At Meridiani Planum, the Opportunity rover becomes a stranger in a strange land.

"This site will truly be an alien landscape. It will not look like anywhere we have been before on Mars," said James Rice, a Mars Exploration Rover scientist from the Arizona State University in Tempe.

Rice said he expects Opportunity to drop into colorful territory, perhaps a deeper, darker reddish brown with splashes of gray.

"All that pesky bright dust that we are familiar with will be absent," Rice told SPACE.com. The chances of encountering fantastic layered sediments will be much higher in Meridiani than at Gusev Crater, he explained.

These layers may be visible in small mesas and buttes. Moreover, the landscape appears to have been stripped by the wind. There will also be far fewer rocks than at Gusev, roughly half the rock abundance seen in the images returned by Spirit, Rice said.

"We may also see dune forms and small impact craters depending on where we put down in the landing ellipse," Rice added.


Gray hematite

Opportunity's targeted landing area is an ellipse about 53 miles (85 kilometers) long and 6.8 miles (11 kilometers) wide.

This zone is within a large region near the planet's arbitrarily designated prime meridian, or line of zero longitude. "Planum" means plains. So the name suits the territory. Meridiani Planum is one of the smoothest, flattest places on Mars.

Meridiani Planum has been found to contain the detectable mineral signatures for coarse grained gray hematite - a type of iron oxide mineral. This type of hematite generally forms in water.

On Earth, gray hematite usually -- but not always - forms in association with liquid water. Some environmental conditions that can produce gray hematite, such as a lake or hot springs, could be quite hospitable to life. Others, such as hot lava, would not.

"I can't predict what we'll find at this time," said Ray Arvidson, Deputy Principal Investigator for the MER endeavor from Washington University in St. Louis. When hematite was first detected from Mars orbit, "it kind of called to us to go to it," he explained at a JPL press briefing here this morning.

Joy Crisp told SPACE.com that the hematite-laden site could have been a more favorable environment for life, than say an ice-covered lake discovered at Gusev Crater. "That's the whole issue. Was there little warm water niches where water hung around long enough…for life to get started," she said.


On course cruise

Like its twin on the other side of Mars, Opportunity will use a rock abrasion tool and two spectrometers attached to the rover's arm to resolve what martian environment produced the hematite at Meridiani Planum.

"I think we're going to see some very interesting terrain," said Steve Squyres, Principal Investigator for the MER program and a space scientist from Cornell University.

Mission planners decided Thursday to skip an optional trajectory correction maneuver (TCM #5) for Opportunity as it cruises toward Mars. There is still time to fine-tune the spacecraft's aim point within Meridiani Planum, moving Opportunity's landing zone to be within better range of terrain features of interest. A "go/no-go" decision on TCM #6 to tweak the spacecraft's landing spot is to be decided tonight.

Opportunity is right on course to land halfway around Mars from Spirit.

"We expect everything to work nominally on Opportunity," said Charles Elachi, Director of JPL. "But still you have the risk of any entry, descent and landing…it's always risky."

Editor's Note: Opportunity's landing is slated for 12:05 a.m. EST on Sunday, Jan. 25. That corresponds to 9:05 p.m. PST on Saturday, Jan. 24 in the mission control room at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

[Oaichehai]

ma non è che alla fine di ogni articolo in inglese si può fare un piccolo sunto in italiano o tutt'al più in spagnolo?
tanto per essere partecipe.......

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Originariamente inviato da Oaichehai
ma non è che alla fine di ogni articolo in inglese si può fare un piccolo sunto in italiano o tutt'al più in spagnolo?
tanto per essere partecipe.......

MER-B, il secondo rover (Opportunity) sta per arrivare sul pianeta rosso, pressapoco sul lato opposto di Spirit.

Ammarterà sulla pianura Meridiani (Meridiani Planum) sabato alle ore 9:05 pm PST (ora del pacifico), 12:05 am EST (ora della costa est) o, per noi, domenica mattina alle 6:05.

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Opportunity, due for Mars landing, gets its big chance

PASADENA, California (AFP) Jan 24, 2004

Opportunity, the second of two NASA rovers, is slated to land on Mars overnight Saturday as its troubled twin, Spirit, finds itself in a "critical state" on the Red Planet.
If all goes well, Opportunity should make its Martian landing at around 0505 GMT Sunday on the Meridiani Planum, described by NASA as one of the "smoothest, flattest places on Mars." That after Spirit, now plagued with communications troubles, arrived on Mars January 3 in the Gusev crater.

Opportunity scientist Joy Crisp said Meridiani "meets our criteria for a safe landing and is an excellent place for science."

NASA scientists are being extremely cautious.

Analysis of Spirit's descent through Mars's atmosphere for its landing at Gusev has contributed to a decision by flight controllers to program Opportunity to open its parachute higher than had been planned earlier, said the Jet Propulsion Laboratory's Wayne Lee, chief engineer for development of the rover's descent and landing systems.

The two golf-cart-sized solar-powered rovers were to study the dusty Martian surface's geological characteristics for three months, trying to determine if the planet ever had conditions that were conducive to life.

The European Space Agency (ESA) said final efforts to coax a call from Europe's lost Martian lander Beagle 2 would take place this weekend, but the chances of success are negligible. The British-built mini-lab was due to have landed on December 25 but has failed to radio home.

Theories that the Red Planet was once awash with water received dramatic backing, meanwhile, from data relayed to Earth from Europe's unmanned spacecraft Mars Express.

Initial results from Mars Express sketched an image of a planet whose surface was once sculpted by seas and glaciers and confirms indications that its South Pole is capped by frozen water, ESA said.

Spirit landed January 3 and had been functioning nearly perfectly until Wednesday, beaming back to Earth spectacular color photographs of the surface of the Red Planet. But communications were abruptly cut off Wednesday and were only partially restored on Friday.

NASA officials expressed concern that the problems could take weeks to sort out and may never be entirely resolved.

"The chances it will be perfect again are not good," Mars Exploration Rover project manager Pete Theisinger told reporters at NASA's Jet Propulsion Laboratory here. "We have got a long way to go with the patient in intensive care.

"It is still in a critical state, but stable," he said. "We don't know what's broken and the consequences. The flight software is not working properly.

"We should expect that we will not be restoring functionality to Spirit for a significant amount of time -- many days, perhaps a couple of weeks -- even under the very best of circumstances," Theisinger said.

Spirit suffered a "very serious anomaly" and stopped normal transmissions on Wednesday, but a signal was received on Friday from the solar-powered rover by one of the giant antennas of the international Deep Space Network near Madrid.

The transmission speed of 120 bits a second was well below the normal speed of 11,000 bits a second, but even the weak signal was welcomed after two days of worrying silence punctuated by an occasional meaningless "beep."

The Meridiani Planum, where Opportunity is supposed to touch down, is a zone of grey hematite, an iron oxide. Scientists plan to use research instruments on Opportunity to determine whether the grey hematite layer comes from sediments of a former ocean, from volcanic deposits altered by hot water or from other ancient environmental conditions.

NASA engineers plan to ask Spirit to provide further information about its condition in an effort to work out why the rover fell silent on its 19th day on the Red Planet.

The breakdown came just as the rover was to begin searching for signs that there may have been water on Mars that could have sustained life.

The 820-million-dollar Spirit and Opportunity project is the most ambitious ever to Mars.

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Per chi vuole vedere in diretta l'arrivo di Opportunity:

NASA TV

January 24, Saturday
- 3-4 p.m. - Opportunity Landing Update - JPL
- 5-6 p.m. MER Briefing - JPL
- 7-8 p.m. - Briefing: "Fireside Chat" with Administrator O'Keefe and JPL Director Dr. Charles Elachi - JPL
- 10:30 p.m. - Opportunity Mission Coverage and Commentary - JPL

ore EST, che per noi si traduce in:

Sabato 24/1

- 21:00-22:00 - Opportunity Landing Update - JPL
- 23:00-00:00 - MER Briefing - JPL

Domenica 25/1

- 01:00-02:00 - Briefing: "Fireside Chat" with Administrator O'Keefe and JPL Director Dr. Charles Elachi - JPL
- 04:30 p.m. - Opportunity Mission Coverage and Commentary - JPL

ARRIVO: DOMENICA 25 GENNAIO 2004, ORE 06:05

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2345 GMT (6:45 p.m. EST)

Louis D'Amario, the Mars Exploration Rover navigation team chief, says Opportunity remains on course for arrival on the plains of Meridiani tonight at about 12:05 a.m. EST (Earth Receive Time) after a seven-month, 280-million voyage.

The cigar-shaped landing zone is 46 miles long and 4 miles wide, which is 0.001 percent of the martian surface, he said.

To guide Opportunity to its landing site, controllers had the chance to perform five Trajectory Correction Maneuvers, plus one contingency burn. But just three were needed.

"We managed to target Opportunity to the desired atmospheric entry point, which will bring us to the desired landing point, using only three Trajectory Correction Maneuvers in that 280 million mile trip from Earth to Mars.

"If you remember back to the Spirit (pre-landing) press conference, I used the analogy to playing a very long hole in golf. For Spirit, only used four shots -- four Trajectory Correction Maneuvers -- so we got a birdie. But for Opportunity we only used three, so we got an eagle. We did even better!"

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0035 GMT (7:35 p.m. EST Sat.)

The in-coming Opportunity rover is getting ever closer to Mars. Time to touchdown is now just four-and-a-half hours away.

Before the fiery entry into the Martian atmosphere can occur, the ring-shaped cruise stage must be jettisoned from the descent module containing the Opportunity rover. This is scheduled for 11:44:46 p.m. EST.

Entry interface occurs at 11:59:46 p.m. EST as the spacecraft punches into the upper fringes of the atmosphere about 128 kilometers above the planet's surface while traveling 5.4 kilometers per second (12,000 miles per hour). The protective heat shield is designed to withstand the 2,600-degree F temperature expected from the friction of falling through the atmosphere. Peak heating will happen around 12:01:28 a.m. at an altitude of 42.6 kilometers.

With about two minutes left in the descent, at 12:03:49 a.m. and 8.9 kilometers above the ground, the craft's parachute will be deployed.

Based upon the reconstruction of data gathered during Spirit's descent and weather reports about the atmosphere above Meridiani Planum, engineers have decided to have Opportunity open its parachute slightly earlier than Spirit did.

At 12:04:19 a.m. and an altitude of 5.8 kilometers, the bottom half of the aeroshell descent module is jettisoned, exposing the lander. The top half of the shell, still riding the parachute, will lower the lander on a small tether.

Activation of the radar altimeter occurs at 5.4 kilometers above the surface at 12:04:24 a.m. The descent imaging camera system initiates at 12:05:07 a.m. at an altitude of two kilometers.

The impact-cushioning airbags surrounding the lander will inflate at 12:05:31 a.m., followed a half-second later by ignition of retro rockets on the upper shell to bring the descent speed to zero. The tether will be cut about 12 meters above the surface at 12:05:34 a.m.

The first moment of touchdown -- starting a series of bounces -- is targeted for 12:05:37 a.m. EST (0505:37 GMT).

The spacecraft is expected to bounce and roll for several minutes before coming to rest.

Mission Control hopes to receive communication "tones" from the rover throughout the entry, descent and landing.

We will be posting updates on this page all evening!

[Oaichehai]

grande Giofx!!!

peccato che per quell'ora starò ronfando.....

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Originariamente inviato da GioFX
Per chi vuole vedere in diretta l'arrivo di Opportunity:

NASA TV

January 24, Saturday
- 3-4 p.m. - Opportunity Landing Update - JPL
- 5-6 p.m. MER Briefing - JPL
- 7-8 p.m. - Briefing: "Fireside Chat" with Administrator O'Keefe and JPL Director Dr. Charles Elachi - JPL
- 10:30 p.m. - Opportunity Mission Coverage and Commentary - JPL

ore EST, che per noi si traduce in:

Sabato 24/1

- 21:00-22:00 - Opportunity Landing Update - JPL
- 23:00-00:00 - MER Briefing - JPL

Domenica 25/1

- 01:00-02:00 - Briefing: "Fireside Chat" with Administrator O'Keefe and JPL Director Dr. Charles Elachi - JPL
- 04:30 p.m. - Opportunity Mission Coverage and Commentary - JPL

ARRIVO: DOMENICA 25 GENNAIO 2004, ORE 06:05

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0235 GMT (9:35 p.m. EST Sat.)

As Opportunity's landing nears and engineers continue to examine Spirit's trouble, here are some words from NASA's space science chief Ed Weiler:

"I appreciate that by now you realize that landing on Mars is really tough and operating on Mars is even tougher, as we found out. We warned you of that three weeks ago (at Spirit's landing).

"Some of you and probably some of us have gotten used to success after success after success. But as we've have seen, exploration is a roller coaster. We've had the early ups and now we've had a down. It seems like we're back going up again. However, I can absolutely guarantee you there will be more downs and there will be more ups with both Opportunity and Spirit.

"However, what the last few days has proven to me is that we have got the absolute best team on Earth operating these (rovers)."

Traveling from NASA Headquarters in Washington to the Jet Propulsion Laboratory for tonight's landing, Weiler thought he'd find a dark mood at JPL mission control given the ailing Spirit.

"I came here expecting to be literally at a funeral. I arrived here yesterday at 3 o'clock and things were looking pretty grim. But already last night things were looking a little bit better and then things got a lot better early this morning. There is a lesson in that."

This morning controllers were able to narrow the search for Spirit's ailment, giving officials renewed hope that the rover can resume its exploration of Gusev Crater in a couple of weeks.

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0325 GMT (10:25 p.m. EST Sat.)

An assessment poll of flight controllers has been performed in advance of Opportunity making its turn to the atmospheric-entry orientation. No significant issues were reported with the spacecraft, the Deep Space Network tracking system or Mars Global Surveyor orbiter that will be used to receive data from Opportunity during landing.

The turn is expected to begin at 10:34 p.m. EST.

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0335 GMT (10:35 p.m. EST Sat.)

Opportunity's landing is now 90 minutes away as NASA attempts to put its second Mars Exploration Rover on the surface of the Red Planet.

Although Spirit's landing was completely successful, giving confidence that tonight's descent of Opportunity will have a positive outcome, project manager Pete Theisinger cautions that nothing is assured when traveling to another planet with complex machines.

"I think you need to understand what the Spirit has proven and what is has not proven. The design of the two vehicles are identical but they are separate vehicles. So the Spirit has proven the design -- this entry, descent and landing system can work. But it has not established the integrity of Opportunity," Theisinger says.

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0336 GMT (10:36 p.m. EST Sat.)

The turn to entry attitude is underway. This rotation will orient the spacecraft such that the heat shield is facing the atmosphere. Prior to this time, Opportunity was flying with its cruise stage solar panels pointed at the Sun and communications antenna in line with Earth.


0337 GMT (10:37 p.m. EST Sat.)

Opportunity is currently 10,880 miles from Mars, traveling at 7,683 miles per hour.


0345 GMT (10:45 p.m. EST Sat.)

The rover's turn appears to be largely complete at this time, Mission Control reports.


0354 GMT (10:54 p.m. EST Sat.)

Opportunity is currently 8,268 miles from Mars, traveling at 7,758 miles per hour. The craft's speed will continue to increase as the Martian gravity pulls Opportunity to the planet.


0400 GMT (11:00 p.m. EST Sat.)

Landing of Opportunity in the Meridiani Planum region of Mars is now just one hour away!

Meridiani Planum is considered one of the smoothest, flattest places on the Red Planet.


0412 GMT (11:12 p.m. EST Sat.)

The turn to entry attitude has been verified complete. The pointing error is 0.37 degrees, which is well within margin.

This turn was a critical event prior to Opportunity making the fiery plunge into the atmosphere by reorienting to put the heat shield facing the planet. Had the turn not occurred, the craft would burn up during entry.


0414 GMT (11:14 p.m. EST Sat.)

Heaters are being activated to condition solid rockets used by gas generators aboard the lander. The generators inflate the impact-cushioning airbags moments before touchdown.


0415 GMT (11:15 p.m. EST Sat.)

The spacecraft is 5,522 miles above Mars, traveling at a velocity of 8,094 miles per hour.

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0431 GMT (11:31 p.m. EST Sat.)

Opportunity is currently 3,334 miles from Mars, traveling at 8,817 miles per hour.

Mission Control confirms that the gas generator heaters are active.

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0453 GMT (11:53 p.m. EST Sat.)

Opportunity is cocooned with its descent module called the aeroshell. The aeroshell which has two parts -- a heat shield that faces forward and a backshell.

Here is an overview:

The system for getting each rover safely through Mars' atmosphere and onto the surface relies on an aeroshell, a parachute and airbags. The aeroshell has two parts: a heat shield that faces forward and a backshell. Both are based on designs used successfully by NASA's Viking Mars landers in 1976 and Mars Pathfinder in 1997.

The parachute is attached to the backshell and opens to about 15 meters (49 feet) in diameter. The parachute design was tested under simulated martian conditions in a large wind tunnel at NASA's Ames Research Center near Sunnyvale, Calif.

The backshell carries a deceleration meter used to determine the right moment for deploying the parachute. Solid-fuel rockets mounted on the underside of the shell reduce vertical velocity and any excessive horizontal velocity just before landing.

The airbags, based on Pathfinder's design, cushion the impact of the lander on the surface. Each of the four faces of the folded-up lander is equipped with an envelope of six airbags stitched together. Explosive gas generators rapidly inflate the airbags to a pressure of about 6900 Pascal (one pound per square inch). Each airbag has double bladders to support impact pressure and, to protect the bladders from sharp rocks, six layers of a special cloth woven from polymer fiber that is five times stronger than steel. The fiber material, Vectran, is used in the strings of archery bows and tennis racquets.

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0459 GMT (11:59 p.m. EST Sat.)

ENTRY INTERFACE. Opportunity's "six minutes of terror" has begun as it makes a fiery descent into the Martian atmosphere, slowing from 12,000 miles per hour to zero in the next six minutes.


0500 GMT (12:00 a.m. EST)

Opportunity is 73 miles above the planet, traveling at 12,187 miles per hour, 441 miles uprange from the landing site.