Mars Exploration Rover Mission

JPL ^ | 1-3-04 | JPL

[bonesmccoy]

Mission Timeline: Entry, Descent, and Landing

The entry, descent, and landing (EDL) phase begins when the spacecraft reaches the Mars atmospheric entry interface point (3522.2 kilometers or about 2,113 miles from the center of Mars) and ends with the lander on the surface of Mars in a safe state.

The rovers will arrive during the latter half of the northern winter/southern summer on Mars. Rover A will land at approximately 2:00 p.m. local time on Mars (with Earth set an hour after landing), whereas Rover B will land at around 1:15 p.m. local time on Mars (with Earth set as long as two-and-a-half hours after landing). That means that both rovers will land in the Martian afternoon while the Earth is still in view, allowing the Earth to receive the landing signal if the lander is on the base petal.

Entry, descent, and landing for the Mars Exploration Rover mission is an adaptation of the Mars Pathfinder method:

An aeroshell and a parachute decelerate the lander through the Martian atmosphere.

Prior to surface impact, retro-rockets are fired to slow the lander´s speed of descent, and airbags are inflated to cushion the lander at surface impact.

After its initial impact, the lander bounces along the Martian surface until it rolls to a stop.

The airbags are then deflated and retracted, and the lander petals and rover egress aids are deployed.

Once the petals have opened, the rover deploys its solar arrays, and places the system in a safe state. Communications during entry, descent, and landing will occur through a pair of low-gain antennas, one mounted on the backshell and the other on the rover itself. About 36 ten-second radio tones will be transmitted to Earth during descent through the atmosphere, which takes approximately six minutes. These tones are coded to indicate the accomplishment of critical steps in the entry, descent,and landing timeline. [More on these tones in the communications section]

A step-by-step guide to everything that will happen will be provided prior to entry, descent, and landing.

[LibertyAndJusticeForAll]

Thanks for posting!

[bonesmccoy]

you're welcome... will post more info and monitor the JPL info over the next 24 hours.

If JPL pulls this stunning achievement off, they will be the greatest robotics team on Earth.

[NormsRevenge]

I hear ya.. There is no guaranteed anything at this point in space exploration, especially when it comes to Mars, it would seem.

Even the simplest spacecraft face huge odds when the time to deploy and perform arrive.

The use of air bags has worked, before.. Here's to another success tonight.

I hope Beagle2 is located and able to be contatced and salvaged, I think the MARS Express is supposed to be attempting to locate and contact Beagle2.

It has 4 or 5 time windows when it will be in a position to scan that area where Beagle2 should have landed.

[bonesmccoy]

um... if landing is 8:30 PM PST, that's NOT 5:30 EST...it's 11:30 PM EST.

[bonesmccoy]

I was watching the NASA MER press conference from six months ago. If the facts remain true, there is a capability for different international spacecraft to "network" autonomously.

If Beagle 2 actually made it to the surface, they should hear from the vehicle.

The different international teams were working out comm protocols to permit data exchange and relay from surface vehicles through international orbiting spacecraft.

[blam]

"um... if landing is 8:30 PM PST, that's NOT 5:30 EST...it's 11:30 PM EST."

Right. Something is wrong with the time. Fox News just said 5:35PM EST for the landing. Does anyone know what's up? Is Fox News wrong?

[Howlin]

Well, see how deficient I am in math........LOL.

Thanks again!

[bonesmccoy]

Here's clarification of the exact predicted landing time

America's Spirit Is Ready to Rock-n-Roll Martian Style Saturday Night

In a perfect world, or in this case two perfect worlds -- Earth and Mars, the first of NASA's two robot geologists will bounce over rocks and roll to a safe stop on the martian surface shortly after 8:35 p.m. PST this Saturday, January 3, 2004.

NASA's twin rovers, named Spirit and Opportunity, have been cruising through the frigid temperatures of space toward Mars for seven months, traveling about 300 million miles. Spirits of the engineers and scientists who have worked on this mission for the last three years will likely heat up around 7:04 p.m. PST when the Spirit spacecraft rotates to face its heat shield forward for final approach. The first step the rover will take in shedding more than half of the spacecraft it has been traveling in should occur at 8:14 p.m. PST, when the entry vehicle is scheduled to separate from the cruise stage. The rover should come screaming into the Martian atmosphere going 12,000 mph at 8:29 p.m. PST.

During the next six terrifying yet thrilling minutes, Spirit will jettison its heat shield, deploy its airbags, fire its retro rockets, cut loose its backshell and parachute, and bounce against the martian surface at 8:35 p.m. PST. The rover, protected by a lander structure and airbags, could bounce up to five stories high and rock and roll as far as 1 kilometer (0.6 mile) across the martian ground before it completes its grand finale stop before 8:45 p.m. PST.

Through the sequence of events this Saturday, Spirit will initially communicate with Earth through a series of simple tones -- imagine the harmonic tones in the movie Close Encounters of the Third Kind, but with a different melody and a much slower tempo. The Deep Space Network antennas on Earth could hear from Spirit Saturday night, but may not receive the first signal from a healthy spacecraft until Sunday evening. Within the first 24 hours, Spirit will have several chances to communicate with Earth both directly to the Deep Space Network and through NASA's Mars Global Surveyor orbiter and NASA's Odyssey orbiter. Both orbiters currently collect science at Mars and cruise above the martian surface at 400 km (250 miles), and they will each fly over Spirit's landing site, Gusev Crater, throughout the mission.

To watch Spirit's rover team and mission controllers live during the landing events from Jet Propulsion Laboratory in Pasadena, California, please tune into NASA TV, beginning at 6:45 p.m. PST.

[bonesmccoy]

Yes. FNC is wrong.

It's 8:30 PM EST...5:30 PM PST.

See above.

Please tell Fox News to cover it live.

[timpad]

JPL's site says 8:35 PM PST, so 11:35 PM EST, 10:35 PM Central

[rs79bm]

8:35 PM PST = 11:35 PM EST

[bonesmccoy]

correction... now I'm confused by the thread... it's as in the post above... 8:30 PM PST. 11:30 PM EST.

It looks like there will not be confirmation of safe landing for about 24 hours (when signals and comm is established)

[rs79bm]

JPL gives the following landing: 8:35 PM PST = 11:35 PM EST.

[blam]

"correction... now I'm confused by the thread... it's as in the post above... 8:30 PM PST. 11:30 PM EST."

"It looks like there will not be confirmation of safe landing for about 24 hours (when signals and comm is established)"

Thanks. Watching the news at the above time will not verify a success or failure of the mission, correct?

[Phil V.]

Has anybody here been following THIS ONE . . . NASA Spacecraft Makes Great Catch...Heads for Touchdown January 1, 2004 . . . Team Stardust, NASA's first dedicated sample return mission to a comet, passed a huge milestone today by successfully navigating through the particle and gas-laden coma around comet Wild 2 (pronounced "Vilt-2"). During the hazardous traverse, the spacecraft flew within about 230 kilometers (143 miles) of the comet, catching samples of comet particles and scoring detailed pictures of Wild 2's pockmarked surface.

[Antoninus]

Wow, can't wait. Fingers are crossed that they'll be able to pull it off.

[bonesmccoy]

Thanks...you are correct.

great video on NASA TV right now showing animation of the landing sequence and deployment

This mission has been wanted for 30 years.

The photos will be superb.

Earth sets about one hour after landing. So, if they can't get an immediate signal out, it will be a while.

The Mars Observer spacecraft is flying over the area and may be able to relay signals. I'll be the JPL engineers have rigged a way to relay through the orbital spacecraft.

Mars rotates once on it's axis every 1.03 Earth days.

So, the timing of when we'll hear that the landing is successful may be Sunday night.

[Pete'sWife]

"I can see the American Flag off in the distance!!!"

[blam]

"NASA Spacecraft Makes Great Catch...Heads for Touchdown January 1, 2004 . . . Team Stardust."

The retrieved samples will not return to earth until 1-15-2006.

[glock rocks]

LOL!